Full text of "Radio Electronics (May 1986)"

HOW TO MAKE
KIRLIAN PHOTOGRAPHS



$1.95 MAY 1986

IN CANADA i'i.btl



ECHNOLOGY - VIDEO - STEREO - COMPUTERS - SERVICE

WILD THIS ^

CRATCH FILTER —

et rid of unwanted
licks and pops
rom your LP's.

UILD A



GERNSBACK




une in to a new
vorld of informatio

REQUENCY COUNTERS^

■tow to get the most from your counter.

WILD A CAPACITOR LEAKAGE

^ow to test capacitors the right way,

IEW SENSOR TECHNOLOGY

ntegrated sensors offer a new way to
Yiake physical measurements.

\ REVOLUTION IN
ELECTRONICS PACKAGING

Jet ready for surface -mount technology.

PLUS:




* Ask R-E * Satellite TV * ComputerDicbst

* PC Service * Robotics

* Antique Radios * New Ideas



TPL^ 2236100MHZ

Cr\ OSCILLOSCOPE



THE ANSWER

BY ANY MEASURE



100 MHz scope, counter, timer,
multimeter: All one integrated system,



100 MHz dual

time base scope,
3.5 ns risetime;
sweeps from 0.5 s
to 5 ns/div; alter-
nate sweep; ±2%
vertical/ horizon! a I
accuracy; vert-
ical sensitivity to
2 mV/div @
90 MHz.



9-digit fluores-
cent display.

Digitally accurate
readouts accom-
pany the CRT
waveform. Error
messages and
prompts also
appear on the
display.



Dc volts and ac
coupled true
RMS volts. Mea-
sured through the
Ch 1 scope input.



Gated measure-
ments. Use the
scope's intensified
marker to measure
frequency, period,
width and to count
events within
specified portions
of the signat.



Auto- ranged,
auto-averaged

counter/ timer.
Frequency, period,
width, delay time,
A -time, plus total-
ize to more than
8 million events
— with 7 digits
plus exponent
displayed,



Auto-ranged
DMM. Use floating
DMM side inputs
with up to 5000-
count resolution.
Get precise read-
outs of average dc
and true RMS volt-
age. Measure
resistance from
milliohms to
gigohms.




Now make measurements
faster, easier, with greater
accuracy and user confidence.

The Tek 2236 makes gated coun-
ter measurements, temperature,
time, frequency, resistance and
voltage measurements push-
button easy. You see results con-
currently on the 9-digit numeric
readout and CRT display.

Its complete trigger system
includes pushbutton trigger view,
plus peak-to- peak auto, TV
line, TV field, single sweep and
normal modes.



At just $2650? the 2236
includes the industry's first 3-year
warranty on all parts and labor,
including the CRT.

Integrated measurement
system. 3-year warranty. 1 5-
day return policy. And expert
advice. One free call gets
it all! You can order, or obtain lit-
erature, through the Tek National
Marketing Center. Technical per-
sonnel, expert in scope applica-
tions, can answer your questions
and expedite delivery. Direct
orders include probes, operating



manual, 15-day return policy, full
warranty and worldwide service
back-up.

Order toll-free:
1-800-426-2200
Extension 57

In Oregon call collect;
(503) 627-9000 Ext. 57
Or write Tektronix, Inc.
P.O. Box 1700
Beaverton, OR 97075



Tektronix

COMMfTTED TO ? XCE UENCE



Copyright k>1984. Tektronix, Inc. All rights reserved TTA-324-1. 'US Domestic price F O B Beauerion. Oregon Pncesubiect to change

CIRCLE 262 ON FREE INFORMATION CARD



May '86



Electronics

Electronics publishers since 1908



Vol, 57 No. 5



BUILD THIS 46 CLICK AND POP FILTER FOR YOUR STEREO

Get rid of scratches from your LP's

electronically. Joe Gorin
51 CAPACITOR-LEAKGE TESTER

Now you can test capacitors the right way.

Gary McClellan
67 TELETEXT DECODER

Decode World System Teletext signals and

find out what you've been missing from TV.

|. Daniel G if ford
75 PC SERVICE

Use the direct-etch foil patterns to make

circuit boards for your teletext decoder and

capacitor- leakage tester.



TECHNOLOGY 10 VIDEO NEWS

A review of the fast-changing video scene.

David Lachenbruch
43 HOW TO MAKE KIRLIAN PHOTOGRAPHS

Investigate this controversial photographic

process yourself. (You don't even need a

camera!) John lovine
59 A REVOLUTION IN IC PACKAGING

Get ready for surface-mount technology.

TJ Byers
63 MAKING MEASUREMENTS WITH IC's

New integrated sensors promise a revolution

in measurement technology. Harry L. Trietley
71 ALL ABOUT FREQUENCY COUNTERS

Part 2. This month we look at some rather

sophisticated applications for your counter.

Vaughn D. Martin
80 SATELLITE TV

An update on satellite scrambling.

Bob Cooper, Jr.
83 ROBOTICS

A look at Heath's Hero 2000. Mark J. Robillard



CIRCUITS AND
COMPONENTS



32 NEW IDEAS

Ignition cutoff switch

88 DESIGNER'S NOTEBOOK
Schmitt triggers.
Robert Grossblatt

89 STATE OF SOLID STATE
New op-amp IC's.
Robert F. Scott



RADIO

85 ANTIQUE RADIOS

Contributions from SWL's.
Richard D. Fitch

90 COMMUNICATIONS
CORNER
Fiber optics. Herb Friedman



COMPUTERS

Following COMPUTER DIGEST

page86 Upgrading your Sinclair,
Home remote control.



EQUIPMENT
REPORTS

22 Triplett 6500 Cable Tester
26 Regency MX- 7000 Scanner

DEPARTMENTS

118 Advertising and Sales Offices

118 Advertising Index

6 Ask R-E

120 Free Information Card

1 2 Letters

95 Market Center

38 New Products

4 What's News



ANNUAL INDEX
JANUARY—DECEMBER 1985

A 4-page brochure containing the 1 985 An-
nual Index is available for those who need
one. To get your free copy, send a stamped
self-addressed envelope, (legal size) to:

Radio-Electronics

Annual Index

500-B Bi-County Boulevard

Farmingdale, NY 1 1 735

Any requests postmarked on or before July
31 are free. After that date there is a 50c fee.
Questions and comments about anything
other than the Index that are included with
your request cannot be handled. Send them
separately to our Editorial Offices.



Radio-Electronics, (ISSN 0033-7i62) May 1966. Published monthly by Gerrtsback Publications, Inc , 500-B Bi-County Boulevard, Farmingdale, NY 11735 Second-Class Postage paid at

Farmingdale. NY and additional mailing olfices. Second-Class mail registration No. 9242 authorized at Toronto, Canada. One-year subscription rale U.S.A. and possessions $15,97. Canada

$20.97, all clher countries $23.47. Subscription orders payable in US funds only, international postal money order or check drawn en a U.S.A. bank. Single copies 51.95. ? 1966 by Qernsback

Publications. Inc. All rights reserved. Printed In U.S.A.

POSTMASTER: Please send address changes to RADIO-ELECTRONICS, Subscription Dept.. Box 2520, Boulder, CO 80322.

A stamped self-addressed envelope must accom pany all submitted manuscripts and/or artwork or photog raphs if 1 heir return is d esi red should they be rejected. We disc lai m any res pons i h il ity lor ; h e

loss or damage of manuscripts and/or artwork or photographs while in our possession or otherwise.



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Cover 1



Can a conventional LP ever sound like a
compact disc? Well, not exactly, but if you
build this click and pop filter for your hi-fi,
you can make your LP's sound almost as
noise-free! The filter lets you rid your LP's of click
by scratches in the vinyl. Yet it still lets you enjoy
range as recorded.

This month, we'll give you the full circuit detail
theory of operation. We'll conclude the article
complete construction details. Turn to page 46.




s and pops caused
the full frequency

s and describe the
next month with



Next Month



THE JUNE ISSUE IS
ON SALE MAY 1

A SPECIAL SECTION ON LASERS

After we introduce you to lasers, we'll show you how
to build a helium-neon laser for yourself!

BUILD AN FET STEREO-AMPLIFIER

This high-quality 100-watt-per-channel amplifier is
just what you need to upgrade your stereo system.

BUILD A 30-VOLT, 1-AMP POWER SUPPLY

Complete your electronics workbench with this ad-
justable supply.

HOW THE TELEPHONE WORKS

We'll solve some of the mysteries of telephone hard-
ware and the telephone system.



As a service to readers, Radio-Electronics publishes available plans or information relating to newsworthy products, techniques
and scientdic and technological developments. Because of possible variances in Ihe quality and condition of materials and
workmanship used by readers. Radio-Electronics disclaims any responsibility lor Ihe sale and proper lunclioning of reader-buill
projects based upon or Irom plans or Information published in this magazine.

Since some of the equipment and circuitry described In RADIO-ELECTRONICS may relate to or be covered by U.S. patents.
RADIO-ELECTRONICS disclaims any liability for the infringement ol such patents by Ihe making, using, or selling of any such
equipment or circuitry, and suggests that anyone interested in such projects consult a patent attorney.



Electronics

Hugo Gernsback 11884-1967) founder
M. Harvey Gernsback,
editor-in-chief, emeritus



Larry Sleekier, EHF, CtT, publisher

EDITORIAL DEPARTMENT
Larry Sleekier, editor-in-chief
Art Kleiman, editorial director
Brian C. Fenton, managing editor
Carl Laron, W82SLR, associate editor
Jeffrey K. Holtzman,

assistant technical editor
Robert A. Young, assistant editor
Julian S. Martin, editorial associate
Byron G. Wels, editorial associate
M. Harvey Gernsback,

contributing editor
lack Darr, CtT, service editor
Robert F. Scott,

semiconductor editor
Herb Friedman,

communications editor
Bob Cooper, Jr. satellite-TV editor
Robert Grossblall, circuits editor
David Lachenbruch,

contributing editor
Richard D. Fitch,

contributing editor
Mark |. Robi I lard, robotics editor
Ten Scaduto, editorial assistant
ludilh Kaplan, editorial assistant

PRODUCTION DEPARTMENT
Ruby M. Vee, production director
Robert A. W. Lowndes,
editorial production
Andre Duzanl, technical illustrator
Karen Tucker, advertising production
Geoffrey S. Weil, production traffic

CIRCULATION DEPARTMENT
lacqueline P. Cheeseboro,

circulation director
Wendy Alanko,

circulation analyst
Theresa Lombardo,

circulation assistant

Cover photo by Robert Lewis

Typography by Mates Graphics

Radio -Electronics, Gemsback Publica-
tions. Inc., Executive Offices, 500-B Bi-
County Blvd., Farmingdale, NV 11735,
516-293-3000

Radio-Electronics is indexed in
Applied Science & Technology Index
and Readers Guide to Periodical Liter-
ature.

Microfilm & Microfiche editions are
available. Contact circulation depart-
ment for details.

Advertising Sales Offices listed
on page 110.



m



m3f:




NEW!

Lower Price

Scanners

Communications Electronics"
the world's largest distributorof radio
scanners, introduces new lower prices
to celebrate our 15th anniversary.

Regencyl MX7000-EA

List price S699.95/CE price S399. 95/SPECIAL
10- Band, SO Channel ? Crystalleaa ? AC/ DC

Frequency range: 25-550 MHz. continuous coverage
and 800 MHz. to 1.3 GHz. continuous coverage.
The Regency MX7000 scanner lets you monitor
military, F.B.I., Space Satellites, Police and Fire
Departments, Drug Enforcement Agencies, Defense
Department, Aeronautical AM band, Aero Navigation
Band, Fish & Game, Immigration, Paramedics,
Amateur Radio, Justice Department, State Depart-
ment, plus thousands of other radio frequencies
most scanners can't pick up. The Regency MX7Q00
is the perfect scanner for intelligence agencies that
need to monitor Ihe new 800 MHz. cellular telephone
band. The MX7000. now at a special price from CE.

Regency? Z60-EA

List price $299. 95/CE price $179. 95/SPECIAL
8- Band, 60 Channel ? No-crystal scanner
Bands: 30-50, 8B-10B, 1 18-136. 1 44-1 74, 440-51 2 MHz.

The Regency Z60 covers all the public service
bands plus aircraft and FM music for a total of
eight bands. The Z60 also features an alarm
clock and priority control as well as AC/DC
operation. Order today.

Regency? Z45-EA

List price S259.95/CE price $1 59. 95/SPECIAL
7-Band, 45 Channel ? No-crystal scanner

Bands. 30-50, (7S-T36, 144-174, 440-512 MHz.
The Regency Z45 is very similar to the Z60 model
listed above however it does not have the commer-
cial FM broadcast band. The Z45, now at a
special price from Communications Electronics.

Regency? RH250B-EA

List price S613.00/CE price $329. 95/SPECIAL
10 Channel ? 25 Wolt Transceiver ? Priority

The Regency RH250 Bis a ten-chan nelVHF land
mobile transceiver designed to cover any fre-
quency between 150 to 162 MHz. Since this
radio is synthesized, no expensive crystals are
needed to store up to ten frequencies without
battery backup. All radios come with CTCSS tone
and scanning capabilities. A monitor and
night/day switch is also standard. This trans-
ceiver even has a priority function. The RH250
makes an ideal radio for any police or fire
department volunteer because of its low cost
and high performance. A UHF version of the
same radio called the RU1 SOB covers450-482
MHz. but the cost is S449. 95. Toget technician
programming instructions, order a service man-
ual from CE with your radio system.

NEW! Bearcat? 50XL-EA

List price S1 99. 95/CE price S1 14.95/SPECIAL
10- Band, 10 Channel ? Handheld scanner

Sands: 29.7-54, 136-174, 406-512 MHz
The Uniden Bearcat 50 XL is an economical,
hand-held scanner with 10 channels covering
ten frequency bands. 1 1 featu res a keyboard lock
switch to prevent accidental entry and more.
Also order part # BP50 which is a rechargeable
battery pack for $14,95, a plug-in wall charger,
part # AD1 00 for$ 1 4,95, a carrying case part #
VC001 for $14.95 and also order optional
cigarette lighter cable part # PS001 for$14.95.




NEW! Regency? XL1 56- EA

List price S239.95/CE price SI 29. 95/SPECIAL
6 -Band, 10 Channel e No-cry s tal Scanner
Search * Lockout * Priority * AC/DC

Bands: 30-50, 144-174, 440-512 MHz.
Cover your choice of over 15,000 frequencies
on 10 channels at the touch of your finger.
Display messages. Externa! speaker jack. Tele-
scoping antenna. External antenna jack. AC/DC.

NEW! Regency? R1 060- EA

List price S149.95/CEprice$92.95/SPECIAL
6- Band, 10 Channel * Crystalless * AC only

Bands: 30-50, 144-174, 440-512 MHz

Now you can enjoy computerized scanner ver-
satility at a price that's less than some crystal
units. The Regency R1060 lets you in on all the
action of police, fire, weather, and emergency
calls. You'll even hear mobile telephones.

Bearcat? DX1 000- E A

LiStprtce$649.95/CEprice$349.95/SPECIAL
Frequency range 10 KHz to 30 MHz.
The Bearcat DX1QO0 shortwave radio makes tuning in
London as easy as dialing a phone. It features PLL
synthesized accuracy, two time zone 24-hour digital
quartz clock and a built-in timer to wake you to your
favorite shortwave station. It can be programmed to
activate peripheral equipment like a tape recorder to
record up to five different broadcasts, any frequency,
any mode, while you are asleep or at work. It will receive
AM. LSS P USB. CW and FM broadcasts.

There's never been an easier way to hear whet Ihe
world has to say. With the Bearcat DX1 000 shortwave
receiver, you now have direct access to the world.

NEW! Regency HX1200-EA

List price S369. 95/CE price S21 4. 95/SPECIAL
8- Bund, 45 Channel ? No Crystal scanner
Search * Lockout ? Priority ? Scan delay
Sidelit liquid crystal display ? EAROM Memory
New Direct Channel Access Feature
Bands: 30-50. 118-136, M4-174, 40B-420. 440-512 MHz.
The new handheld Regency HX1 200 scanner is
fully keyboard programmable for the ultimate in
versatility. You can scan up to 45 channels at the
same time including the AM aircraft band. The LCD
display is even sidelit for night use. Order
MA-256-EA rapid Charge drop-in battery charger
for ?84.95 plus ?3.00 shipping/handling. Includes
wall charger, carrying case, belt clip, flexible
antenna and nicad battery.

NEW! Bearcat? 100XL-EA

List price S349.95/CE price S203. 95/SPECIAL
9- Band, 16 Channel * Priority * Scan Delay
Search ? Limit ? Hold ? Lockout * AC/ DC

Frequency range: 30-50, 113-174, 406-512 MHz.
The world's first no-crystal handheld scanner now has
a LCD channel display with backlight for low light use
an d a ire raft band coverag e at t he same low price. Size is
1 W % 7Vj" x Vh" The Bearcat 1 00XL has wide frequency
coverage that includes all public service bands (Low,
High, UHF and "T" bands), the AM aircraft band, the 2-
meter and 70 cm. amateur bands, plus military and
federal government frequencies. Wow.. .wh at ascanner!
Included In our low CE price is a sturdy carrying case,
earphone, battery charger/ AC adapter, six AA ni-cad
batteries and flexible antenna. Order your scanner now.

Bearcat? 210XW-EA

List price $339. 95/CE price S209. 95/SPECIAL
8- Band, 20 Channel ? No- crystal scanner
Automatic Weather ■ Search/Scan ? AC/DC
Frequency range: 30-50, 136-174, 406-512 MHz.
The new Bearcat 21 OXWis an advanced third generation
scanner with great performance at a low CE price.

NEW! Bearcat 1 45XL-EA

List price $1 79 .95/CE price S1 02. 95/ SPECIAL
10 Band, 1B channel ? AC/DC * Instant Weather

Frequency range: 29-54. 136-174, 420-512 MHz.
The Bearcat 1 45XL makes a great firsl scanner. Its low

cost an d h igh perto rma n ce I et s you hea r a 1 1 the act io n wit h
Ihe touch of a key. Order your scanner from CE today,

TEST ANY SCANNER

Test any scanner purchased from Communications
Electronics 1 " for 31 days before you decide to keep it. II for
any reason you are not completely satisfied, return it in
original condition with all parts in 31 days, for a prompt
refund (less shipping/handling charges and rebate credits).



Regency

MX7OO0




NEW! Bearcat? 800XLT-EA

List price S499. 95/CE price S31 7.95
12-Band, 40 Channel ? No-crystal scanner
Priority control * Search/Scan * AC/DC

Bands: 29-54, 11S-174, 406-512, 806-912 MHz.
The Uniden 8O0XLT receives 40 channels in two banks.
Scans 1 5 channels per second. Size9Vi" xAWx 12*4."
OTHER RADIOS AND ACCESSORIES

Panasonic RF-2600-EA Shortwave receiver SI 79.95

RD95-EA (Jmden Remote mount Radar Detector. . . S1 28.95

RD5S-EA Uniden Visor mount Radar Detector S98.9S

ROSEA Uniden" Passport" size Radar Detector .. 5239.95
BC 2 1 0XW-EA Bearcar20 channel scanner SALE. . . S 209.95

BC-WA-EA Bearcat Weather Alert- 549.95

0X1 000- EA Bearcat shortwave receiver SALE. .5349.95
PC22-EA Uniden remote mount CB transceiver. . . . ?99.95
PC55-EA Uniden mobile mount CB transceiver. . 559 95
R1 060-EA Regency 1 channel scanner SALE — ?92.35

MX30UO-EA Regency 30 channel scanner S1 93.95

XL15S-EA Regency 10 channel scanner SALE... S12B.95
UC1 02-EAflegency VHF2 ch. 1 Watt 1 ran sceiver . . . S1 24.95
RH250 B-EA Regency 1 ch. 25 Watt VH Ftrans. . . 5329,95
RHeoo B- E A Regency i - - 60 Wall VH F trans S454 55
R U1 50 B- EA Regency 1 channel U H F transceiver , 5449.95
RPH410-EA 50 ch handheld no-crystal Irans.. ...S399.95
LC10-E A Carrying case forRPH4i0 Iransceiver .534.95
MAI 81 - EA Ni-cad ballery pack for RPH4 10 trans. . . S34.95
PI 405- EA Re genc/5 amp regulated powersupply . . . 569.95
P141 2-EA Regency 12 amp re?. power supply. . . S1 S4.95
BC10-EA Battery charger lor Recency RPH410 ...584.95
MA25SEA Drop-in charger lor H XI 000 S HX1 200 . . SS4.95

MA257-EA Cigerelle lighter cord lor HX1 20O 519.95

MA91 7-EA Ni-Cad battery pack lor HX1 200 534.95

EC1 0-EA Programming tool for Regency RPH41 . . . S24.95
SMRH250-EA Service man. for Regency RH250 ... 524 95
SMRU150-EAServiceman.forRegencyRU150 . , .S24.95
SMRPH41 0- EA Service man. [or Regency RPH41 .524.95
SMHX70O0-EA Sva man for MX70O0 f. MX5000 , . S 1 9.95
S M M X3000- E A Service m an. for Regency M X3000 . 519.95

B-4-EA 12 V AAA Ni-Cao batteries (set of four) 59.95

FB- E-EA Frequency Dlrecloryfor Eastern U.S A .... 51 2.95
FB-W- E A Frequency Directory for Western U.S- A,. . . S 1 2.95
TSG-EATopSecret" Registry of U.S. Gov! Freq. . .514.95

TiC-EA Techniques lor Intercepting Comm... 514.95

RRF- EA Railroad frequency directory SI 0.95

C I ?- E A Cove rl I nt ell ig enct, Elec t. Eav esd rop pi ng . . . 5 1 4 . 95
ASO-EA Magnet mount mobile scanner antenna. . . ?35.00

A7C-EA Base slalion scanner antenna 535.00

USAM M-EA Mag mount VH F/U HFanl. w/ 1 2 1 cable . . , S39.95
USAK-EAW holemounlVHF/UHFant.w/17'caole . . .535.00

USATLM-EATrunklipmounlVHF/UHFantenna ?35.00

Add 53.00 sh i ppmg tot al I a ccesson es ordered at i he sam e t ime.

Add SI 2.00 shipping per shortwave receiver.

Add 57.00 shipping per scanner and 53.00 per antenna

BUY WITH CONFIDENCE

To get the fastest delivery from CEof any scanner,
send or phone your order directly to our Scanner
Distribution Center" Michigan residents please add 4%
sales tax or supply your tax LD. number. Written pur-
chase orders are accepted from approved government
ag en cies an d most we 1 1 rat ed firms a t a 1 0% s u re h a rg e
for net 10 billing. All sales are subject to availability.
acceptance and verification. Ail sales on accessories
are final. Prices, terms and specifications are subject to
change without notice. All prices are in U.S. dollars. Out
of stoc k it e m s wit I be pi aced on bac ko rde r a utom at ical I y
unless CE is instructed differently, A S5.00 additional
handling lee will be charged for all orders with a
merchandise total under SS0.00, Shipments are F.O.B.
Ann Arbor, Michigan. NoCOD's, Most products that we
sell have a manufacturer's warranty. Free copies of
warranties on these products are available prior to
purchase by writing to CE. Non-certified checks require
bank clearance.

Mail orders to: Communications Electron-
ics!" Box 1045, Ann Arbor, Michigan 48106
U.S.A. Add $7,00 per scanner for U. P. S. ground
shipping and handling in the continental U.S.A.
For Canada, Puerto Rico, Hawaii, Alaska, or
APO/FPO delivery, shipping charges are three
times continental U.S. rates. If you have a Visa
or MasterCard, you may call and place a credit
card order. Order toll-free in the U.S. Dial
800-USA-SCAN. In Canada, order toll-free by
calling 800-221-3475. Telex CE anytime, dial
810-223-2422. If you are outside the U.S. or in
Michigan dial 313-973-8888, Order today.
Scanner Distribution Center" and CE logos are trade-
marks of Communications Electronics Inc.
t Bearcat is a registered trademark of Uniden Corporation.
J Regency is a registered trademark of Regency Electronics
Inc. AO*040tS6-EA

Copyright 1966 Communications Electronics Inc.

For credit card orders call

1-800-USA-SCAN



c



COMMUNICATIONS
ELECTRONICS INC.



I



Consumer Products Division |

P O. Box 1045 D Ann Arbor. Michigan 46 1 06-1045 U.S. A
Call 80O-USA-SCAN oroutslde U.S.A. 31 3-973-6888



CIRCLE 79 ON FREE INFORMATION CAHD



WHAT'S N EWS



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AES prints new standards
for audio measurements

The S4 Committee of the Audio
Engineering Society {AES} has now
been accredited by the American
Standards Institute for the de-
velopment and publication of
standards in the audio engineer-
ing field. As a result, AES has pub-
lished five ANSI-approved stan-
dards:

AES2-1984 (ANSI S4.26-1984), Rec-
ommended practice for specifica-
tion of loudspeaker components
used in professional audio and
sound reinforcement;
AES5-1984 (ANSI S4. 28-1984). AES
recommended practice for profes-
sional digital audio applications
employing pulse-code modula-
tion — preferred sampling fre-
quencies;

AES7-1982 (ANSI S4.6-1982). Meth-
od of measuring recorded flux of
magnetic sound records at medi-
um wavelengths;



AES6-1982 (ANSI S4.3-1982), Meth-
od for measurement of weighted
peak flutter of sound recording
and reproducing sound equip-
ment;

AES3-1985 (ANSI S4.40-1985). AES
recommended practice for digital
audio engineering — serial trans-
mission format for linearly repre-
sented digital audio data.

Those documents are available
at $15 each from the Audio Engi-
neering Society, 80 East 42nd St.,
New York, NY 101 65.

Video cassette recorders
making record increases

Over 11 million VCR's have been
purchased in 1985, a 55 percent
gain over 1984, according to Step-
hen Stepnes of RCA Consumer
Electronics. By 1988, he says, there
will be 50 million VCR's in Amer-
ican homes.

The proportion of high-fidelity
table-model stereo VCR's is also



New capacitor used as energy storage device



"A new energy-storage device
that never needs replacement" is
the way its man ufactu rer descri bes
the Maxcap Double-/.ayer Ca-
pacitor (DLC), a unit with up to 500
times the energy density of an alu-
minum electrolytic capacitor of




THE SOHIO MAXCAP 1 farad capacitor.



similar dimensions.lt is intended
to replace batteries in applications
requiring low drain, such as
CMOS RAMS, microprocessors,
and timers.

The secret of the new capacitor
is the electrode material : activated
carbon, which can have a surface
area of 1,000 square meters per
gram. The working voltage is low,
necessitating the double-layer
principle, in which up to six acti-
vated-carbon, liquid-electrolyte
units may be stacked to reach the
5-volt rating of the capacitor illus-
trated.

An ideal application is as backup
for CMOS RAM memories, where
the capacitor is kept charged dur-
ing normal operation and where in
case of failure "a thimble-sized
Maxcap can back up CMOS mem-
ories for weeks."



increasing. Those comprised
about 10 percent of the total VCR
market in 1985 — up from 5 percent
in 1984 — and will rise to more than
14 percent in 1986, according to
Stepnes.

Justice Dept cracks down
on interference

The Department of Justice has
filed suits against two CB oper-
ators and one commercial compa-
ny in Philadelphia for sums
total ling more than $4,000. In addi-
tion the suits seek court orders
mandating that the violators com-
ply with FCC regulations.

F.C. Roberson was operating a
CB radio that caused interference
to numerous residents of a Phila-
delphia neighborhood. The
equipment appeared to be operat-
ing far over the four-watt legal lim-
it. Roberson repeatedly refused to
allow FCC inspection of the radio,
thereby accumulating fines total-
ling $900. The suit seeks payment
of the fines, and a court order di-
recting Roberson to permit in-
spection of his equipment and to
operate it at legal power levels.

Henry O. Jackson was using his
CB radio at an estimated power
level of 47 watts, interfering with
local television reception over a
period of several months. A fine of
$750 was levied against him. The
suit seeks payment of the $750,
and a court order directing Jack-
son to bring his equipment within
FCC guidelines.

The Department of Justice has
also filed suit against Comp-Art,
Inc., for unlawfully interfering
with TV reception with a comput-
er. The interference occurred over
a period of 18 months. Fines of
$3,000 were accumulated. The suit
seeks payment of the fines and a
court order directing Comp-Art to
shield or otherwise modify its
computer so that it will not inter-
fere with local TV reception. R-E



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PEST-REPELLER QUESTIONS

We thank the many readers who
responded to the article "Ultra-
sonic Pest Repellers" that ap-
peared in the July 1985 issue of
Radio-Electronics. We will attempt
to answer some of the more com-
mon questions below. We es-
pecially want to thank readers
Parke 5. Barnard of New Haven,
CT, and Harold J. Read of Grove
City, FL, for sending copies of the
article "Bug Zappers that Don't"
that appeared in the July/August
1985 issue of Science magazine.
? 1. How can I modify one of the
circuits to attract mosquitoes to fly
into an electric bug killer? Many fly-
ing insects are attracted to it, but
mosquitoes seem to ignore it. — S. E.,
Sacramento, CA.

Personally, I'm not convinced
that mosquitoes ignore the UV
lights found in typical electric bug
killers. During the last week or so,
during a particularly heavy infesta-
tion of mosquitoes, I've studied
the operation of the bug killer at
close range. Mosquitoes don't
seem to be lured to the UV light as
easily as other flying insects, but
they are attracted nonetheless.
Mosquitos are small, compared
with the size of the charged grid,
so many are able to fly in to and
out of the charged area without
harm.

One researcher on bug killers
claims that mosquitos are not easi-
ly attracted to the UV light source
in most bug killers, and that a UV
I i g ht of 80 to 1 00 watts i s needed f o r
the killer to be effective in attract-
ing mosquitos.

Recently I read the article "Build
a Better Mosquito Trap" in Home
Mechanix, August 1985. The au-
thor suggested that mosquitoes
are attracted to man and animals



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CRYSTAL DR
CERAMIC
ULTRASONIC
TRANSDUCER
FIG. 1



by odor, moisture, and heat, and
he proposed using a candle to heat
and thereby evaporate water from
a small container placed near the
bug killer. As I recall, the author
also suggested adding a drop or
two of some chemical to create an
enticing odor.

? 2. I'm looking for a good tweeter
to use in my electronic pest repeller.
Radio Shack's piezoelectric tweeter
only responds to about 30 kHz. Your
circuits oscillate as high as 65 kHz,
so it doesn't appear that the Radio
Shack unit will work. — S. Z.,
Brooklyn, NY; J. S,, Taunton, MA;
and J. NL, Morristown, NJ.

There is a lot more to the acous-
tic output and frequency response
of a loudspeaker than you'll find in
a Radio Shack catalog. Speakers
are usually rated to reproduce ei-
ther speech or music. Frequency
response is often quoted in terms
of the low- and high-frequency
points where response drops to a
specific — and often unspecified —
level. In fact, even the manufac-
turer's performance curves don't
tell the full story unless you are
also given a full run-down on all
test conditions.

A speaker's response is gener-
ally tested by applying a constant
voltage of a varying frequency in
series with a resistance that repre-
sents the equivalent source resis-
tance of the driving amplifier. As
the speaker's impedance in-
creases, the voice-coil current and
acoustic output decrease. By ap-



plying constant power across a
band of frequencies, acoustic
power output will be much higher
at high frequencies than at, say,
400 Hz.

There are a number of mail-
order suppliers that sell inexpen-
sive speakers and tweeters suit-
able for use in the pest repeller.
Among them are MCM Elec-
tronics, 856 Congress Park Drive,
Centerville, OH 45459, and
McGee Electronics, 1901 McGee
St., Kansas City, MO 64108. The
latest MCM catalog lists dome-
type tweeters ranging in price
from $4.50 to around $26.00, and
piezoelectric tweeters made by
Motorola ranging from $7.00 to
$11.00.

? 3. In an attempt to get rid of some
pesty black ants, I built the "French"
circuit in Fig. 2 of "Ultrasonic Pest
Repellers;" that circuit uses a 4011. 1
finished construction, but I can't tell
whether my circuit is oscillating. The
4011 is a delicate CMOS IC, so I'm
afraid I may have zapped it. To test
my circuit, we caught several ants,
placed them in a pail, and aimed the
tweeter at them. They scampered
around like crazy, so I think the de-
vice is working — but I'd like to be
sure. Can you suggest a method of
testing it? Incidentally, the sche-
matic specified 560 pF capacitors,
but I used 680 pF units. I suppose
that that altered the frequency.
Could the values of those capacitors
be a problem? — ), W. D., Corning,
NY.

By using a 680-pF capacitor the
frequency will be a little lower, but
still within the effective ultrasonic
range. You can measure frequency
with a scope or a frequency coun-
ter. Shown in Fig. 1 is a simply way
to use a scope to measure both
frequency and amplitude.



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? 4. Can you supply the names of
firms selling low-cost pest repellers
like the one shown in Fig. 1 of "Ultra-
sonic Pest Repellers?"— C. C. D.,
Hesperia, CA; E. T., Wilkes Barre,
PA; W. V., Clifton, Park, NY; and ).
M., Santa Barbara, CA.

A number of firms advertise
electronic pest repellers. We can
endorse neither products nor
manufacturers, so — buyer be-
ware.

Bently's, Box 31445 San Fran-
cisco, CA 94131; Hanover Square,
Building No. 51, Hanover, PA
17333; Bug-A-Way, Phone (800)
222-0354, or Drawer M, Columbia,
SC 29250; The Shelburne Co., 110
Painters Mill Rd., Owings Mill, MD
21117; Fina Merchandise Center,
6310 North Western Ave., Chicago,
IL 60659.

? 5. 1 want to build a pest repeller to
use outdoors in order to get rid of
bees, gnats, flies, etc. Can you
help? — J. A., Forest Hills, NY.

I understand that ultrasonic de-
vices have been used outdoors ex-
perimentally. They use special
transducers and they have much
higher power than the repellers
described in our story. In some
outdoor units sounds in the audi-
ble range are emitted, so the de-
vices are not practical for use
around people. However, they do
have some agricultural applica-
tions. You may be able to get more
information on outdoor pest re-
pellers from AV-Alarm Corp., 675-
D Conger St., Eugene, OR 97402.

? 6. After breadboard ing the circuit
in Fig. T of Ultrasonic Pest Repellers,
I removed the modulating voltage
that is applied to pin 5 of the 555
from the junction of R3 and R4. I
measured the un-swept frequency at
about 50.5 kHz. How can I measure
the overall sweep range? — R. S.,
Creve Coeur, MD.

Here's one way. Use a scope or
multimeter to measure the peak-
to-peak value of the modulating
voltage at the junction of R3 and
R4. Rig up a DC power supply
whose output is equal or higher
than the peak value of the modu-
lating voltage — a couple of 9- volt
batteries in series should suffice.

Connect a potentiometer across
the batteries and connect the
wiper to pin 5 of the 555. Vary the
voltage from zero to the maximum
p-p sweep voltage mesured ear-



lier, and monitor the 555's output
with a frequency counter. Then re-
verse the polarity of the supply
and measure the frequency swing
in the opposite direction.
? 7. I buiit the circuit in Fig. 1 of
Ultrasonic Pest Repellers and it
works, except that it emits a high-
pitched tone that drives some people
from the room. What can I do to
eliminate that tone? — F. C, Winter
Haven, FL.

Evidently, the low end of the
sweep frequency is audible and
annoying to some people. You can
eliminate that annoyance by rais-
ing the 555's base frequency of os-
cillation. Do that by decreasing the
value of CI. Try values of 910, 820,
or even 750 pF.

SIMPLE POWER SUPPLY
I need a power supply that delivers
plus and minus nine volts to replace
two nine-volt batteries in a project
I'm building. Do you have a suitable
design? — N. J. S-, Greensboro, NC

117
VAC




VCT



-0+9V



C2
100 nF, 16V



GROUND

O



— 0-9V



FIG. 2

A ±9-volt supply is shown in Fig.
2. The rectifier circuit is actually
two separate full-wave rectifiers
fed from the secondary of the
transformer. One full-wave rec-
tifier is composed of diodes D1
and D2, which develop +9 volts,
and the other is composed of D3
and D4, which develop -9 volts.

Each diode of each diode pair
rectifies 6.3 volts AC (half the sec-
ondary voltage) and charges the
associated filter capacitor to the
peak value of the AC waveform, 6.3
x 1.414 = 8.9 volts. Each diode
should have a PIV (Peak /nverse
Voltage) rating that is at least twice
the peak voltage from the trans-
former, 2 x 8.9 = 18 volts. The
1N4001 has a PIV of 50 volts. R-E



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Video

News




DAVID LACHBNBB.UCH

CONTRIBUTING EDITOR



O

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LXJ

6

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CC

10



? Competition for 8mm. The camcorder wars
are heating up, as JVC has completely
miniaturized its VHS-C system, tripled its
recording time to a full hour by adding an EP
speed, and added a CCD pickup to compete with
the new 8mm-video camcorders. (You'll recall
that VHS-C is JVC's miniature VHS format, VHS-C
cassettes can be played back by a standard VHS
deck through the use of an adapter.) JVC's new
little wonder is a complete record-and-playbaek
unit with electronic viewfinder, autofocus, and
power zoom; it weighs 2.9 pounds without
cassette or battery. The comparable Sony Video 8
camcorder weighs 4.5 pounds, Sony's little 8mm
Handycam weighs only 2.2. pounds, but it doesn't
play back, and lacks zoom and autofocus.

? Pocket-TV* grows up. The first major TV
brand to introduce a mini set with a color LCD
screen is Panasonic, whose Pocket Watch uses a
3-inch color LCD. It has an audio-video input for
use with a VCR and a pop-up screen with a
backlight for night viewing. Its suggested list
price is $300. Sharp and Toshiba are also
expected to enter the color LCD fold. Meanwhile,
some manufacturers are planning some not-so-
mini LCD color sets. Citizen has shown a 10,6-
inch set and Casio both 6- and 12-inch versions.

? All networks now in stereo. With CBS
joining the fold in February, all four major
television broadcast- networks now are
broadcasting at least some programs in stereo,
and some 250 TV stations are equipped to pass
those programs through to viewers. The EIA
estimates that some 240,000 TV sets with built-in
stereo reception capability were sold in 1984 and
1,500,000 in 1985. The manufacturer's group
forecasts that 2,800,000 will be sold this year.
Those figures don't include the sales of other
devices that can also receive stereo telecasts,
such as stereo-equipped VCR's.

? 1985 records. Americans bought a record
17,261,312 color TV-sets in 1985, including
265,645 projection-TV systems. That total was up



6 percent from 1984, when the previous record
was set. They also bought 11,853,188 home VCR's,
an increase of 55.6 percent from 1984.

? Hade in the U.S_A_ Two major components,
formerly made only abroad, will soon be
manufactured in the US. RCA says it will make
giant 35- inch direct-view color-picture tubes,
with production quantities due in 1988.
Mitsubishi currently is the only manufacturer
making tubes of that size, and they are just
starting production on their giant tube.

Also, ITT is planning to manufacture IC sets for
digital TV sets in the U.S. Previously, they were
available only from ITT's plant in Germany. ITT
hopes that the availability of domestically
manufactured IC's will encourage American
manufacturers to make digital sets. Although U.S.
set makers have developed sets using the ITT IC's,
none has actually gone into production. Digital
sets are being made in Germany and Japan.

? Update. Here's the latest word on a couple of
items reported in this space lately: Last February,
we reported that Eastman Kodak would market a
video-image printer that could make prints from
any video source. That project was put in limbo
as a result of the court ruling that Kodak was
infringing on Polaroid's instant-photography
patents. The color printer was designed to use
the Kodak instant film now banned by the court.
However, Kodak still plans to test-market a
companion product — the video floppy disc, which
can record or play back up to 50 TV fields.

We originally reported here that General
Electric will end its manufacture of color-TV sets
and instead buy them from Matsushita Electric.
Since that report, GE has agreed to purchase
RCA The two events are unrelated. Even though
GE is expected eventually to own RCA and its TV-
manufacturing facilities, it still plans to buy its
sets from Matsushita, which will build a special
plant in Mexico for the purpose. Both companies
say that they will continue to market sets under
their own brand names in two separate
marketing organizations after the merger. R-E





Check out the # 1 source
for technical

RCA.



I ? ?



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Covers Magnavox, Panasonic,
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I llustrations and descriptions.



RCA offers a wide range of literature highlighting our exact replacement parts.
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Replacement Parts for RCA Video
Cassette Recorder Instruments — Helps
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Cross- Reference — Relates RCA's manu-
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Fill in information at left and mail entire page to:
RCA Distributor and Special Products Division
2000 Clements Bridge Road
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Attn: Sales Promotion Services

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Letters



CHALLENGE TO THE VCR AND
CABLE-TV INDUSTRY

I challenge the video and cable-
TV industries to establish a stan-
dard logic interface for connecting
a leased Pay-TV decoder to a sub-
scriber's VCR. The channel selec-
tion programmed into the VCR's
memory timer would tune the de-
coder, which would then deliver
the baseband video and audio sig-
nals to the VCR.

Think of the advantages: 1. Sin-
gle-point control of channel selec-
tion. 2. Elimination of moving
parts in the decoder. 3. No need
for selector switches or splitters.
4. Better-quality signal due to
baseband connection. 5. Simple
option to tape one channel and
watch another. 6. VCR's with re-
mote controls would have full con-
trol.

The technology exists today,
since most VCR's and many cable
decoders use digital channel se-
lection already, if a simple LSTTL
logic interface could be agreed
upon, one of cable subscribers'
most common beefs wouid be sat-
isfied.

ERICG. LEMMON
Lompoc, CA

DIGITAL TV CIRCUITS

Recent articles have appeared
discussing the various TV formats
such as PAL, SECAM, NTSC, ad-
vances like HDTV, new PBS pro-
posed formats such as MAC, and
associated signal-handling meth-
ods. It seems to me that the TV
designers are spending a lot of en-
ergy in the wrong direction. I refer
mainly to the domestic TV receiver
designs using analog methods. Let
me explain briefly, and perhaps
spark some thought.

If the received broadcast signal






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were digitized right out of the first
IF filter, then the format could be
transparent to the display system
used. Indeed, the display could be
scanless, mapping the data extrac-
ted from the signal only as neces-
sary to create the picture; and it
would be void of the many inter-
ferences caused by relationships
between various frequency com-
ponents in the normal scan and
signal elements.

The processor would discover
the transmission format, the re-
lated color and audio signals, pro-
cess the data and feed it to the
output devices. Thus the TV re-
ceiver could be updated easily
(with ROM perhaps) to process
any new formats and features.

The technology is here today.
Why aren't such TV's on the mar-
ket? Maybe they are, and just not
advertised. How about an article
on digital TV circuits? I don't mean
digital control, I mean real full-
scope digital TV from the IF out.

I enjoy Radio-Electronics!
GENE SIMMONS
Riyadh, Saudi Arabia

A HAPPY NEW SUBSCRIBER

I am a new subscriber to your
magazine and just wanted to let
you know what a great surprise
your magazine is for me. For years
I subscribed to Popular Elec-
tronics, which became Computers
& Electronics, and then became
extinct. My interest has always
been in the digital electronics
area, and I thought that Popular
Electronics was the only magazine
that covered the subject. I knew
that your magazine existed, but I
had always assumed it was strictly
forthose interested in analog elec-
tronics. Well, at the demise of
Popular Electronics I began to look



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for an alternative; a friend assured
me that my assumptions were
wrong and that Radio Electronics
was for me — and the rest is history.

I am up to my third issue and I
haven't been disappointed yet. As
a matter of fact, I'm quite pSeased
and excited. I have a great interest
in home-control system design
and I'm planning some experi-
ments using the Commodore-64
as the development and control
processor, with additional hard-
ware and software that I have de-
signed. I'm looking foward to
building the Printer Buffer and
EPROM Burner covered in your
August and September 1985 is-
sues. I am hoping to download
custom software to EPROM's to be
used in my control system. Could
you recommend kits for making
circuit boards from the foil pat-
terns that are included in your arti-
cles? I designed circuit boards in
college, but the process was te-
dious, and it involved very expen-
sive equipment. I would greatly
appreciate any information you
could send me on PC-board de-
sign and construction. Is it possi-
ble that you will do something on
that subject in a future issue?
THOMAS F. DUN [CAN
Plymouth, NH

We may do an article on that
subject, Tom, but to tide you over,
you might check the December
1982, January 1983, and February
1983 issues of Radio-Electronics for
an excellent three-part article by
Robert Grossblatt on that subject.
A shorter treatment by the same
author appears in the September
and October 1985 issues of Radio-
Electronics. In addition, we have a
reprint of several articles on de-
signing and etching PC boards
available. See the reprint order
form elsewhere in this issue. — Edi-
tor

RESTORING AN OLD MARCONI

I am trying to restore an old Mar-
coni TV set (TV 500 chassis) to its
original working condition, but 1
am unable to find a schematic or
repair manual from the usual
sources. The chassis appears to
have a problem in the horizontal
phase detector circuit, which is a
type I have not encountered be-
fore. I would appreciate any help
you or your readers could give me



in locating information about that

chassis.

P.C. DODD

18 Lakeland Cres.,

Scarborough, Ontario,

Canada MIC 213

SMALL LOW-COST PROJECTS

I have been enjoying Radio Elec-
tronics for about a year now, and I
find it to be a worthwhile and en-
joyable expenditure of time and
money. I read with interest the flap
about Radio-Electronics's turning
into another computer magazine,
and I think you are doing rather
well on that subject. Ignoring
computers at this time would as
ludicrous as leaving out TV be-
cause this is a "radio" magazine;
but I hope you continue to stick to
computer "electronics" and leave
the software to someone else.

My reason for writing, however,
concerns some of the projects
you've published lately. While the
$2500 IBM look-alike ("PC Com-
patible Computer," July, 1985)
would be great to build, and was
fun to read, and while a $200 see-
in-the-dark doo-hickey ("See-ln-
The-Dark Viewer", August, 1985)
would be fun for a few weeks, how
practical is it really, and how many
of your thousands of readers have
hundreds of bucks to spend on
that type of "tinkering?"

I think I speak for a number of
people who would like to see
some small, low-cost, beginners'
projects for those of us who are
still new at this. One suggestion
would be tuning and construction
of garage door-opener transmit-
ters and receivers. I have two or
three of each, but none match.
Building a 12-volt transmitter to
permanently mount under the
hood and match to your existing
receiver would be a great little
project. Home security seems to
be pretty popular right now, also. I
don't believe that projects have to
be on the cutting edge of tech-
nology to be useful and timely.
TROY B. LAMINACK
Dumas, Texas

Troy, we sympathize with you,
and that's why we created Hands-
on Electronics, our sister publica-
tion. We like your garage-door-
opener idea; get busy, designers!
And, by the way, for an interesting



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approach to a complete home-se-
curity system, see the December,
1985, and January, 1986 issues of
Radio-Electronics. — Editor

INTERESTED IN OLD-TIME RADIO
EQUIPMENT

Since Radio-Electronics readers
are interested in old-time radio
equipment and pioneers like
Tesla, Marconi, DeForest, and
Armstrong, 1 have a request. Does
anyone anyone know where to
borrow, rent, or buy an Alexander-
son Alternator that could be made
to work?

How those things operate fasci-
nates me, so any written material
on the subject would be welcome.
If my understanding is correct,
one could get one of those things
on the air with little more than a
big carbon microphone, and with-
out vacuum tubes. Is that so?

The Alexanderson is a relatively
unknown item from radio history,
and as such it would make a good
display at the Tesla "Unconven-
tion" here in California next July.
The attendees will definitely be in-
terested in that type of demonstra-
tion.

PETE LEFFERTS
1640 Decker Ave.
San Martin, CA 95046.

COMB FILTERS FOR YOUR TV

In Neil W. Heckt's August, 1985
article, "Comb Filters for your TV,"
Mr. Heckt derives 3,579,485 Hz. as
the chrominance subcarrier (S.C.)
frequency. As you can see from the
FCC's Rules and Regulations,
Section 73.682, paragraph five:

The chrominance subcarrier fre-
quency is 63/88 times precisely 5
MHz (3.57954545... MHz). The tol-
erance is ±10 Hz and the rate of
frequency drift must not exceed
0.1 Hz per second (cycles per sec-
ond squared)

The chrominance subcarrier is
the only numberthat is specifically
enumerated (3,579,545 Hz.) and all
other values are derived from it,
not the other way around.

If Mr. Heckt is just using the fig-
ures in his article for the sake of
clarity in his explanation, he
should indicate that usage.
ARBY SCHUMAN
Megazap Telemetry Systems

You are indeed correct regard-
ing the derivation of the horizon-



tal-scanning frequency from the
specified color-burst frequency
rather than the other way around
as I stated in my article.

The relationship of horizontal,
vertical, and color burst frequen-
cies, rather than their exact values,
is the most important aspect of the
spectral nature of the NTSC signal;
those relationships define how to
separate chrominance from lumi-
nance information.

I simplified the values of the fre-
quencies and their derivation, and
I concentrated on their rela-
tionship, most important of which
is that the color burst flag is 455/2
times the horizontal sampling fre-
quency (i.e., CBF=(455/2)HSF

You are correct in pointing out
that the inverse mathematical rela-
tionship is specified by the FCC,
(i.e., HSF=(2/455)CBF, and that
the actual CBF =3.57954545 MHz.
—Neil W. Heckt

THANKS FOR THE HELP

My recent request for help in
your magazine resulted in three
responses, one of which was a
complete owner's manual for the
Sansui AM/FM receiver 1 was hav-
ing trouble with! Another re-
sponse was a full-page typed letter
describing practical approaches to
trouble-shooting and fault loca-
tion in the absence of a schematic.

Now 1 need an address where I
can obtain operating instructions
for a DORO 311 telephone-answer-
ing machine manufactured for
Dictran International by Victor Co.
of Japan.
M. MCDANIEL
940 Temple ST.
San Diego, CA 92106

CORRECTION
Sharp-eyed reader Chris
Bassett, of the Bronx, NY, called
my attention to an error that crept
into the text of my article, "All
About Multipath Distortion" in the
October, 1985 issue of Radio-Elec-
tronics. On page 76, in the center
column between the first and sec-
ond paragraphs, the formula for
horizontal spacing (H) is given as
(X/2) sin 9. The parentheses were
wrongly placed; the formula
should be:



H = \/(2 sin 9)
BOB SCOTT
Darlington, SC



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pair, power cord, and multi-con-
ductor shielded cable (although in
high-density, multi-conductor ca-
bles, the range may be somewhat
restricted due to high inter-con-
ductor capacitance).

Measurements are displayed on
a 4-digit LCD readout. Annun-
ciators on the readout indicate
whether a cable fault is a short or
open, and whether the displayed
distance is in meters or feet.

The cable to be measured is con-
nected to the unit via a front-panel



BNC jack. If more convenient, the
cable can be connected via bind-
ing posts if the included binding-
post-to-BNC adapter is used.

In most ways, the unit is very
easy to use; we'll get to the excep-
tion in a moment. All operation is
controlled via four front-panel
controls. Three pushbuttons are
used to turn the unit on or off; set
the measurement units, either
meters or feet, and to set the
range, either short (15-600 feet) or
long (600-6000 feet).



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With our ACE 109 and t!8 blue bread-
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AP Products 100 series breadboards
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more expensive circuit evaluators. The
spring terminals have mechanically in-
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modate most DIPs and discrete compo-
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The ACE 109 has two terminals for sepa-
rate voltages plus a ground connection.
The larger ACE ffl offers the same three
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which can be used for clocking or
another voltage. The bookplates are
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s^*/^y^



The fourth control, a pushbut-
ton counter, requires a bit more
explanation. It is used to select the
cable's NVP (Normal Velocity of
Propagation). That quantity is
equal to the reciprocal of the
square root o f the cable's dielectri c
constant (1/V dielectric constant ,
and is different for different types
of cables. For instance, coax using
a polyethylene dielectric usually
has an NVP of 66. Often, the NVP
can be found in or derived from
the cable's data sheets. If not, the
value must be determined experi-
mentally. That's the exception that
was referred to previously.

To find the NVP of the cable to
be tested, a 15- or 30-foot length of
the same cable must be connected
to the 6500. Then, at an ambient
temperature of 23°C <±5°C), dif-
ferent settings of the NVP switch
are tried until the readout displays
15 or 30 feet (depending on the
length of the test cable). Once the
NVP of the cable is determined, it
should definitely be written down
for future reference.

Housed in a black high-impact
plastic stand with bale-type han-
dle, the 6500 is powered by 6 C-
sized nickel-cadmium batteries.
Also included is an AC adapter/
battery-charger, and car-cigarette-
lighter adapter.

The manual that accompanies
the unit is a bit sketchy and slop-
pily done. It provides a fair expla-
nation of how the unit is used, and
gives some specifications, but
does little else. Notably, there is
no schematic, theory of operation,
or similar information.

At a list price of $550, this is not a
product aimed at the hobbyist
market. But if you are involved
with the installation, mainte-
nance, or repair of cables, the time
and aggravation that the 6500 can
save you is well worth its cost. R-E



24



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A very special computer &
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Challenge. Knowledge. Achievement. Enjoy-
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CIRCLE 86 ON FREE INFORMATION CARD



CL-787R1



Regency MX-7000
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A top-of-the-line scanner
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90










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WHEN WAS THE LAST TIME YOU TOOK A

close look at a scanner? Granted,
they've been around long enough
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some of the new ones, like the
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a closer look; those units feature
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The MX-7000 is a micro-
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section features continuous
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MHz and 1.1 GHz. Among the
scanner's more unusual features
are memory retention for up to a
week without battery backup, and
adjustable bandwidth. Other fea-
tures include a 20-channel memo-
ry, dual scanning speeds, and a
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A powerful package

The MX-7000's technology is
packed in a case that measures just
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weighs a light 2.4 pounds. A nice
touch is the slanted front panel.
That design places the front panel,
with its membrane keyboard and
LCD readout, at a convenient an-
gle for viewing and use. The front
pane) also sports a power switch;
volume control; squelch control;
display-tight switch, which allows
you to illuminate the readout in
less-than-optimum lighting condi-
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when activated locks out the key-
pad to prevent accidental entries.

The keypad is used to select op-
erating modes as well as frequen-
cies. The available modes include
scan, search, frequency lockout,
priority and clock. Further, the up-
per and lower search-limits, re-
ceiver bandwidth, scan delay, scan
speed, time of day (for the clock),
and memory selection are set
using the keypad.

The selectable bandwidth is an
especially useful feature as it helps
ensure clean, clear reception. On
scanners that use fixed band-
widths, distortion and adjacent-



channel interference are common
problems, especially when
monitoring narrow-bandwidth FM
transmissions. With the MX-7000,
if you are listening to an area of the
spectrum where most communi-
cation is done using5-kHz narrow-
band FM, you can program the
scanner for a 5-kHz bandwidths.
Other available bandwidths are
12.5 and 25 kHz.

The unit offers 20 memory-loca-
tions, or channels; those are pre-
programmed for some of the most
popular listening frequencies.
However not all frequencies are
equally popular in all areas. To



Add a Little Technology
to Your Library.



Solid-State Relay Handbook with
Applications

Anthony Bishop

This comprehensive reference work on solid-state relays
is what electronics technicians, engineers, and hobbyists
have heen waiting for. Bishop treats SSRs on a wide range
of technical levels, from a I filarial approach on the basics
to discussing techniques of installation and designing
interface logic signals with power bads. Its up-lu-lhe-
minute coverage of the use and application of SSRs
discusses improvements in speed and reliability Readers
will find particularly useful ihe applications of SSRs with
microprocessor- based equipment for industrial machine*
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A key feature is the separate chapter on testing
equipment and procedures.
No, Z2^"S, SI9.9t



Handbook of Electronics
Tables and Formulas
(6tb Edition)

Staff of Howard Vi\ Sams
This useful handbook contains
the updated information you
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The new edition contains computer
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equations and formulas. The easy-tu-
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sy nitidis and codes, service and installa-
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formulas you would expect to find in this reference
standard for ihe Industry, New formulas include power
units, graphical reactance relations, power triangle, and
decihels/voliage/power diagram Among the new
constants are standard potentiometer lapers and the
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IC OP-AMP Cookbook (3rd Edition)
flfolter Jung

llohhyists and design engineers will be especially pleased
at I his new edition of the industry reference standard on
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No 22453, sik.9t



Understanding Digital Logic Circuits

Robert G. Middleion

Designed for ihe service technician engaged in radio,
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painlessly expands the technician's expertise into digital
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Send s i oo for Sams hook catalog (product No. 903*091
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Nj.u'. .'. i ?■ VIjiI Mil". I .■;■■ u.ll: |.j-.nu!l!M IImMAI * SB** & Cu
Iiil lh|H t)\\ * i -((|i i ■??,-?[ in "ihE Mni-[ ? fimluii3|Nihv l\ itijliM



Regency




MX-7000




OVERALL

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EASE

OF USE
















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^


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change the frequency stored in
one of the channels is not difficult,
but the procedure is more compli-
cated than with most other scan-
ners. It involves three different
keying sequences, selecting the
programming mode (narrowband
FM, wideband FM, or AM), fre-
quency, and channel.

On the rear panel of the scanner
are found the power, antenna, and
external-speaker connectors. The
unit requires 13.8-volts DC. For
fixed use, that power is provided
by the included wall-plug power
supply.

Rather than the traditional
Motorola connector used by most
scanners, the antenna connector
on this unit is a BNC type. The
advantage of that type of con-
nector is that it is more secure.

Though the unit features its own
built-in speaker, a connector is
provided if you wish to use an ex-
ternal unit. Note that for best per-
formance only eight-ohm speak-
ers should be used.

Also , a 1 0-d B atten uato r i s switch
selectable from the rear panel.
That allows you to deal with signal-
overload problems, such as those
that occur when you are near a
powerful transmitter.

As to specifications, they are im-
pressive for a unit of this type. For
starters, receiver sensitivity is 1.0
H.V at 12 dB SI NAD on the narrow-
band-FM setting and 1.5 \lV at 12
dB SINAD on the wideband-FM
setting. On AM, the sensitivity is
1.5|xVat10dBS/N.

Selectivity is 7.5 kHz at 6 dB
down for narrowband FM; 50 kHz
at 6 dB down for wideband FM,
and 5 kHz at 6 dB down for AM.

Image and spurious-signal re-
jection is better than 50 dB down,
while intermodulation rejection is
better than 50 dB down.

The instruction manual is com-



28



C.O.M.B. BREAKS THE
SATELLITE TV PRICE BARRIER!

KLM 8-ft. SATELLITE



HIGH PERFORMANCE! TOP NAME BRAND!



MWM^Ll^*^




COMPLETE,
PERFECTLY
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? Designed for do-it-
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? Fully programmable lo-
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? Automatic push-
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of each satellite!

? Includes 120 feet
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? Superior quality
throughout!



It opens up a vast new world of TV entertainment! MORE
sports! MORE movies! MORE of
watch! And it provides superior



everything you like to
reception capabilities!



The KLM &-ft. Satellite TV Receiver system picks up
signals from more than a dozen communications

satellites in the sky. This opens up over 100 channels
of TV viewing, with a multitude of programs. And the
KLM system provides outstanding reception capa-
bilities throughout the entire 48 states!

PERFECT FOfl SPORTS FANS! Enjoy much more sports
action and thrills than ever before! You'll literally he "in
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HUGE VARIETY OF ENTERTAINMENT. Watch popular new

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PLUS, there are entertaining and educational channels
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growing LARGER and LARGER!

IDEAL FOR RURAL AREAS! II TV reception is poor or the
variety is very limited where you live, you're in for a
HUGE DELIGHT! With the KLM system, reception is as
good as in a big city. And the variety is huge!



GREAT FOR URBAN AND SUBURBAN AREAS! With the KLM
system, you can still pick up all your usual local
stations. PLUS, you get greatly expanded selection
from all the satellite channels. There's a huge world of
viewing pleasure in store for you. Up to 100 or more TV
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00-IT-YOUBSELF INSTALLATION! You don't have to be an
electronics "whiz" to install the KLM system.
Components come pre- assembled, except for the 8-ft.
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AN EXCELLENT VALUEI Don't be fooled by someone
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One year limited factory
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san". *i9oo.oo



ENTIRE
SYSTEM

Closeout
Price



$




hem H-l 159-5958-004

F.OB Milwaukee Wise, metro area

Shipping weight: appro*. 155 lbs.



FREE WITH YOUR ORDER. Current issue of SATELLITE ORBIT magazine! PLUS money-
saving subscription offer of 15issues for the price of 12. Each issue packed with over 200 pages
of monthly listings for thousands of satellite TV programs to select from.



ABOUT THE MANUFACTURER

KLM introduced the FIRST satellite TV
receiver system for consumers! They
designed the FIRST programmable
receiver. KLM is one of the largest in
the industry and is a leader in advanced
technology. Because they are con-
centrating efforts on new designs,
KLM has allowed us to offer a quantity
of these current 8-ft. models to the
public at an unusually low price! It's a
tremendous value!



INCLUDES ALL THIS, TOO!




SKY EYE X BLOCK RECEIVER!

Uncomplicated, easy operation ! Fast fingertip selection of
channel, polarity, audio tuna. Relative signal strength
meter lets you hit station right on the button. Separate
AFC on/off selector allows precision tuning, even of
weak channels.

INCLUDES blockdown converter (an expensive
option on competitor's models). This splits signals so 2 TV
sets in your home can "tune in" on 2 different channels of
same satellite at same time. However, you need another
receiver (available from regular KLM dealers] for the
second TV set.



HORIZON TO
HORIZON MOUNT

This special mount delivers 180°
range for maximum degree of
"dish" rotation for access to TV
satellites in western hemisphere.
120 feet of cable also included.





Fully Programmable AIMER IV
REMOTE "DISH" POSITIONER

Microprocessor controlled for pushbutton access to �4
pre-programmed satellite locations. Six presets for
favorite satellites. Automatically positions "dish" and
channel skew (polarity). Battery backup for three-month
memory retention in case of power failure of for un-
plugging system during vacations;. Parental Lockout
prevents children from viewing restricted channels,

HOW TO SELECT A PROPER SITE

Stand in your yard, look due South and side to side. You
should have an unobstructed view of ihe sky. Tree
branches and power lines diminish quality of reception.



Credit ■: ard customers can
order by phone, 24 hours

a day. 7 days a wee*.

Toil-Free: 1-800-328-0609

Your check is welcome!

No delays in orders paid by check.

Sales outside continental U.S. are subject lo special

conditions. Please call or write to inquire.

C.O.M.B. Direct Marketing Corp. Item H-1159

14605 28th Ave. N,/ Minneapolis, MN 55441-3397

Send KLM S-ft, Receiver Systemls) Item H-1159-

5958-004 at $999 each. I will pay shipping charge to
driver upon delivery. (Minnesota residents add 6% sales
tajt Allow 3-4 weeks for delivery. Sorry, no C.O.D orders.,
D My check or money order is enclosed (No delays in
processing orders paid by check, thanks to Tele Check i
Charge to my; D MasterCard^ □ VISA? *
Acct No Exp. 1



PLEASE PRINT CLEARLY

Name

Address ,

City



Phone L_



Sign Here



C.O.M.B.

DIRECT MARKETING CORP.

Authorized liquidator

14605 28th AVENUE NORTH
MINNEAPOLIS. MN 55441-3397



>
<

ID
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5>



29



R-E Engineering Admart B



Rates: Ads are 2W" x 2W. One insertion S825. Six insertions $800 each. Twelve

rtions S775 each. Closing date same as regular rate card. Send order with

ittance to Engineering Admart, Radio Electronics Magazine, 500-B Bi-County

Farmingdale, NY 11735. Direct telephone inquiries to Arline Fishman, area

code-516-293-3000. Only 190% Engineering ads are accepted for this Admart.




CALL NOW
AND

RESERVE
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Call 516-293-3000 to reserve space. Ask

for Arline Fishman. Limited number of
pages available. Mail materials to:
Engineering Admart, RADIO-ELEC-
TRONICS, 5O0-B Bi-County Blvd., Farm-
ingdale, NY 11735.





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Wl - 1.1 lb 2I10V/1.24A
2I21V/0.MA


125 10 S22.CH
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25.10 22.00
36. 10 3!C0


S 19.60
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IS OVA 2XS.SV/7.KA
DD- 1.9" 2S12V/S.MA
H ■ 1 ?" 2i1!?/4.O0A
Wl ■ 2.2 lb 2.18V 3 330
2x2*V/2.?A
220V/0J5A


J32 20 527.50
32.20 27.50
32.20 27.50
32.20 27.50
32.20 27.50
32.20 27.50


S24 45

24.45
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LINEAR IC EQUIVALENTS
& PIN CONNECTIONS



Linear IC

Equivalent*
and Pin
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Shows equivalents & pin connections of a
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postpaid in USA. ELECTRONIC TECH-
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AND

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? Fast reader service cycle.

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Call 516-293-3000 to reserve space. Ask
for Arline Fishman. Limited number of
pages available. Mail materials to:
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plete and covers the major fea-
tures of the scanner completely. It
also touches on the major specifi-
cations. Overall, it's well done.

As to the price, at a suggested
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not cheap. Even with discounting,
it's cost will likely limit the
MX-7000's appeal to only the most
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for those serious scanner enthusi-
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With its extended frequency
coverage and its ability to tailor
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WE'RE FIGHTING FOR YOUR LIFE



2 SIMPLE

SOLUTIONS TO
227000




RCA's SK Series Replacement Guide (SKG202D) is
your one source for over 206,000 solid state replace-
ments using 2,500 SK and KH types. Integrated circuits,
thyristors, rectifiers, transistors, microprocessors —
RCA has them all.

Likewise, RCA's Industrial MRO Guide (1K7862)
lists over 4,000 devices that replace more than
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Together, these RCA Guides provide fast, easy
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SK Replacement
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31






New Ideas



Simple circuit foils car thieves



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IF YOU LIVE IN A HIGH-CRIME AREA AND

operate an automobile, you're
probably afraid that someday your
car will be stolen. Well, so was I —
until 1 built and installed the igni-
tion cutoff circuit described here.
Since then I sleep much easier.
And the circuit has another bene-
fit: Many insurance companies
will reduce your rates if you install
a cutoff circuit like mine.

What my circuit does is give you
manual control over the voltage
that goes to your car's coil. If 12
volts doesn't reach the coil, it
won't be able to provide the high
voltage that fires the spark plugs.
The starter will still work, so a
would-be car thief will probably
think that there's something
wrong with your car — and he'll
leave it alone.

How it works

As shown in Fig, 1, the heart of
the circuit is a 4PDT relay and a
hidden pushbutton switch. That
switch, the relay's coil, and the ig-
nition switch are all wired in se-
ries, so both switches must be
closed simultaneously to energize
the relay. And since the coil cur-
rent flows through the relay's con-
tacts, the relay must be energized
or current wo n't get thro ugh to the
coil.

The relay has four sets of con-
tacts and all four are used. The
lowest set of contacts functions as
a latch so you don't have to keep
your finger on S2 continuously to
keep coil current flowing. Those
contacts simply keep S2's termi-
nals shorted after the relay has
been energized; that short en-
sures that the relay will remain en-
ergized until the ignition switch is
opened.

Working upward, the next set of
contacts is used to provide visual
indication of what's happening.
After closing the ignition switch



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SWTCH

FIG. 1

LED1 turns on, but the relay is un-
energized, so the car won't start.
But when the relay is energized by
pressing S2, LED2 lights up to indi-
cate that you should be able to
start the car now.

The upper two sets of relay con-
tacts are simply wired in parallel to
provide plenty of current-carrying
ability for the coil-energizing
pulses.

Construction

The circuit can be wired up on a
scrap piece of perf board. None of
the parts are critical; just be sure
that the relay you use can carry the
required coil current. Rather than
use two LED's, I used a single two-
color device. That way I only had
to drill one hole. Be sure to wire a
diode across the coil of the relay,
and in the orientation shown.

To install the ignition cut-off cir-
cuit you'll have to cut several wires
in your car's electrical system and
splice in leads to your circuit
board. You'll have to cut the 12-volt
ignition-switch wire and the 12-
volt coil-supply wire. When you
connect your patches to the circuit
board, make sure to use wire that
is at least as large as the wires you
just cut. And make sure to make
good connections — electrically
and mechanically — to the coil
wires. — Ronald L Goers.



NEW IDEAS

This column is devoted to new ideas, cir-
cuits, device applications, construction tech-
niques, helpful hints, etc.

All published entries, upon publication, will
earn $25. In addition, for U.S. residents only.
Panavise will donate their model 333 — The
Rapid Assembly Circuit Board Holder, having
a retail price of $39.95. It features an eight-
position rotating adjustment, indexing at 45-
degree increments, and six positive lock posi-
tions in the vertical plane, giving you a full ten-
inch height adjustment for comfortable work-
ing.




I agree to the above terms, and grant
Radio-Electronics Magazine the right to
publish my idea and to subsequently re-
publish my idea in collections or compilations
of reprints of similar articles. I declare that the
attached idea is my own original material and
that its publication does not violate any other
copyright. I also declare that this material has
not been previously published.



Title of Idea



Signature



Print Name



Date



Street



City State

Mail your idea along with Ihis coupon
lo: New Ideas Radio-Electronics,
5DD-E Bl-County Blvd.,
Farmlngdale, NY 11735



Zip



32



TM



Super Disk

Diskettes

Now... Diskettes you can
swear by, not swear at.

Lucky for you, the diskette buyer, there are many diskette
brands to choose from. Some brands are good, some not
asgood, and some you wouldn't thinkof trusting with even
one byte of your valuable data. Sadly, some manufacturers
have put their profit motive ahead of creating quality
products. This has resulted in an abundance of lowquality
but rather expensive diskettes in the marketplace.

A NEW COMPANY WAS NEEDED AND STARTED

Fortunately, other people in the diskette industry recognized
that making ultra-high quality diskettes required the best and
newest manufacturing equipment as well as the best people
to operate this equipment. Since most manufacturers seemed
satisfied to give you only the everyday quality now available,
an assemblage of quality conscious individuals decided to
start a new company to give you a new and better diskette.
They called this product the Super Disk diskette, and you're
going to love them. Now you have a product you can swear by,
not swear at.

HOWTHEY MADE THE BEST DISKETTES EVEN BETTER

The management of Super Disk diskettes then hired all the
top brains in the diskette industry to make the Super Disk
product Then these top bananas (sometimes called floppy
freaks) created a new standard of diskette quality and
reliability. To learn the "manufacturing secrets" of the top
diskette makers, they've also hired the remaining "magnetic
media moguls" from competitors around the world. Then all
these world class, top-dollar engineers, physicists, research
scientists and production experts(if they've missed you, send
in your resume to Super Disk) were given one directive.. .to
pool all their manufacturing know-how and create a new,
better diskette.

HOW SUPER DISK DISKETTES ARE MANUFACTURED

The Super Disk crew then assembled the newest, totally
quality monitored, automated production line in the industry.
Since the manufacturing equipment at Super Disk is new, it's
easy for St/per Disk to consistently make better diskettes.
You can always be assured of ultra-tight tolerances and
superb dependability when you use Super Disk diskettes. If
all this manufacturing mumbo-jumbo doesn't impress you,
we're sure that at least one of these other benefits from using
Super Disk diskettes will:

1 . TOTAL SURFACE TESTING ■ For maximum reliability, and to lessen the likelihood of
disk errors, all diskettes must be 'orally surface tested. At Super Dish eaoh diskette is
1 O0% surface tested. Super Disk is so picky in [heir testing, they even test Ihe Iracks lhat
are in between the regular tracks.

2. COMPLETE LINE OF PRODUCTS - For a diskette to be useful to you and your
computer, it musl be compatabie physically. Super Disk has an entire line of Svinch
and 3Vincn diskettes for your computer.

3. SPECIALLY LUBRICATED DISK- Super Disk uses a special oxide lubricant which Is
added to Ihe base media in Ihe production ol their diskettes. This gives you a better disk
drive head to media contact and longer head and disk life.

4. HIGH TEMPERATURE/LOW-MARRING JACKET- A unique high temperature and
low-marring vinyl Jacket allows use of their product where other diskettes won't work. This
special jacket is more rigid than other diskettes and helps eliminate dust on the jacket.

5. REINFORCED HUB RINGS - Standard on all 48 TPI Super Disk mini-disks. 10
strengthen the cenler hub hole. This increases the life of the disk to save you money and
increase overall diskette reliability.

6. DISK DURABILITY - Super Disk diskettes will beat all industry standards lor reliability
since they will give you more than 75% of ihe original signal amplitude remaining even
after an average (Weibul B-50) o!30 million passes. They are compatible wilh all industry
specifications as established by ANSI, ECMA, ISO. IBM and JIS.

7. CUSTOM E R ORi ENTED PACKAGING - All Super Drsd disks are packaged 1 disks to
a carton and 10 cartons to a case. The economybulkpack is packaged 1 00 disks to a case
without envelopes or labeis.

8. LIFETIME WARRANTY- If all else tails, remember, all disks made by Super Drsk Inc.,
have a lifetime warranty. It any Super Disk diskette fails to meet factory specifications.
Super Disk Inc. will replace them under the terms of the Super Disk warranty.

9. SUPERB VALUE - With Super Disk's automated pfoduclron line, high-quality, error-
free disks are yours without the high cost.

Order toll free 800-USA-DISK



NOW.. .NAME BRAND QUALITY AT SUPER CE PRICES

Now, you can buy Super Disk brand diskettes directly from Communi-
cations Electronics at prices less than "unbranded" generic diskettes.
Your data is valuable, so why take chances using a diskette that could
be so unreliable that the manufacturer refuses to put their name on it.
To save you even more, we also offer Super Disk bulk product where
1 00 diskettes are packed in the same box without envelopes or labels.
Since we save packaging costs, these savings are passed on to you.
518" diskette envelopes are also available from us. These super strong
and tear resistant envelopes are only $10.00 per pack of 100. Use
order # CV-5 for a 100 pack of 5'A" diskette envelopes.

390 per disk
Quantity One

Our diskettes are packed 1 disks to a carton and 1 cartons to a case.
The economy bulk pack is packaged 100 disks to a case without
envelopes or labels. For best value, you should order in increments of
100 diskettes. Almost all diskettes are immediately available from
Super Disk. With our efficient warehouse facilities, your order is
normally shipped in less than a day.

Super Disk
SAVE ON SUPER DISK" DISKETTES price

Product Description Part * per disc {?)

5'A" SSSD Soft Sector w/Hub Ring

514" Same as above, but bulk pack w/o envelope

5'A" SSDD Soft Sector w/Hub Ring

5Vj" Same as above, but bulk pack w/o envelope

5'A" DSDD Soft Sector w/Hub Ring

5V Same as above, but bulk pack w/o envelope

5V4 DSQD Soft Sector (96 TPI)

5W" Same as above, but bulk pack w/o envelope

5V.' DSHD for IBM PC/AT- bulk pack

3W SSDD (1 35 TPI) - bu Ik pack

3'A DSDD (135 TPI) -bulk pack

SSSD.= Single Sided Single Density; SSDD = Single Sided Double Density;
DSDD = Double SidedDouble Density: DSQD= DoubleSidedQuadDensity;
DSHD = Double Sided High Density; TPI = Tracks per inch.

BUY YOUR DISKETTES FROM CEWJTH CONFIDENCE

To g et th e f ast est d e I ive ry of yo u r d isket t e s, phone you r ord er d irect ly to o u r
order desk and charge it to your credit card. Written purchase orders are
accepted from approved government agencies and most well rated firms at
a 10"% surcharge for net 10 billing. For maximum savings, your order should
be prepaid. All sales are subject to availabil ity. acceptance and verification.
All sales are final. All prices are in U.S. dollars Prices, terms and speci-
fications are subject lo change without notice. Out of stock items may be
placed on backorder or substituted for equivalent product unless we are
instructed differently. A $5.00 additional handling fee will be charged for all
orders with a merchandise total underSSO.00. All shipments are F.O.B. CE
warehouse in Ann Arbor, Michigan. NoCOD's Non-certified checks require
bank clearance. Michigan residents add 4% sales tax or supply your tax ID
number and reason for tax exemption.

For sh Ipping charges add S6. 00 per 1 00 diskettes and/or any fraction of
1 00 5''4-inchor3V3-inch diskettes for U.P.S. ground shipping and handling in
the continental U.S. For 1,000 or more disks shipped to the continental U.S..
shipping charges are S4.00 per hundred diskettes. UPS 2nd day air rates
are three times continental U.S. rates. For Canada, Puerto Rico. Hawaii,
Alaska, or APO/FPO delivery, shipping is ffiree times the continental U.S. rate.

Mail orders to: Communications Electronics Inc., Box
1045, Ann Arbor, Michigan 48106-1045 U.S.A. If you have a
Visa or Master Card, you may call and place a credit card
order. Order toll-free in the U.S. Dial 800-USA-DISK. In
Canada, order toll-free by calling 800-CA1-D1SK. If you are
outside the U.S. or in Michigan dial 313-973-8888. Telex
anytime 81 0-223-2422, Order your Super Disk diskettes now.



6431 -FA


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6437- FA


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6461 -FA


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6487- FA


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Copyright ? 1986 Communications Electronics Inc.



Ad #040136- FA



Htf^^bb Mini Flr>pp v OKI.
^^^^^^|Lif?li(n? Warranty


■ mmm 1 1 i i 1 " i M




Super
Disk


W



Now

390

a disk



CIRCLE 79 ON FREE INFORMATION CARD



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34



CIE MAKES THE

WORLD OF

ELECTRONICS

YOURS.



TW oday's world is the world of electronics.
To be part of it, you need the right kind of
training, the kind you get from Cleveland
Institute of Electronics, the kind that can take you
to a fast growing career in business, aerospace,
medicine, science, government, communica-
tions, and more.

Specialized training.

You learn best from a specialist, and that's CIE.
We're the leader in teaching electronics through
independent study, we teach only electronics and
we've been doing it for over 50 years. You can put
that experience to work for you just like more than
25,000 CIE students are currently doing all
around the world.

Practical training.

You learn best with practical training, so CLE's
Auto- Programmed? lessons are designed to take
you step-by-step, principle-by-principle. You also
get valuable hands-on experience at every stage
with sophisticated electronics tools CIE-designed
for teaching. Our 4K RAM Microprocessor
Training Laboratory, for example, trains you
to work with a broad range of computers in a
way that working with a single, stock computer
simply can't.

Personalized training.

You learn best with flexible training, so we let you
choose from a broad range of courses. You start



with what you know, a little or a lot, and you go
wherever you want, as far as you want. With CIE,
you can even earn your Associate in Applied
Science Degree in Electronics Engineering
Technology. Of course, you set your own pace,
and, if you ever have questions or problems, our
instructors are only a toll-free phone call away.

The first step is yours.

To find out more, mail in the coupon below. Or, if
you prefer, call toll-free 1-800-321-2155 (in Ohio,
1-800-523-9109). We'll send a copy of CIE's
school catalog and a complete package of enroll-
ment information. For your convenience, we'll
try to have a representative contact you to answer
your questions.



C^b Cleveland Institute of Electronics
I hn 1776 East I7i h Si . C Icvc la nd . Ohio 441 14

YES! I want to get started. Send me my CIE school catalog including
details about the Associate Degree Program. 1 am most interested in:
Z computer repair C television/high fidelity service

□ telecommunications □ medical electronics

□ robotics/automation G broadcast engineering

P other

Prim Name



Addrcy
Cil>_



Apt.



Slaic.



Zip.



Age.



Area Codc/Ptwne No, .



Checkbox for G.I. Bulletin on Educational Benefits
□ Veteran □ Active Duty MAIL TODAY!

OR CALL TOLL FREE

1-800-327-2155

fin Ohio, J -800-523-91 09)

RE-36



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37



New Products




CIRCLE 21 ON FREE INFORMATION CARD



SOFTWARE PACKAGES link the
Tektronix model 7854 Digital Stor-
age Oscilloscope and the model
7D20 Programmable Digitizer
(shown) to IBM and Hewlett Pack-
ard computers. The software pack-
ages are designated the 7854/HP
Series 200, the 7D20/HP Series 200,
and the 7D20/IBM PCtime and am-
plitude measurement software.

With the 7854/HP Series 200 soft-
ware, laboratories can build pro-
grams and issue commands to the
7854 from the computer. Programs
can be stored in the computer
memory or on disk. Like the other
HP program, up to six waveforms
can be shown simultaneously in
different colors on the HP 9836C.
The program is priced at $950.00.

With the 7D20/HP Series 200
software, laboratories can use the
computer to store front-panel set-
ups on the 7D20. When needed,
the setups can be recalled for au-
tomatic waveform acquisition or
other test and measurement func-
tions. The software for the HP
computers is written in HP BASIC



3.0. The programs are written in
modules, enabling users to break
out subroutines, such as the func-
tions necessary for propagation-
delay measurements, and append
them to their own programs. The
package is priced at $950.00.

The TekMap 7D20/HP IBM PC
time and amplitude measurement
software operates with autorang-
ing routines that automatically set
up the 7D20 for positive or nega-
tive edge triggering, or for several
repetitions of a signal for period
measurements. Hence users can
avoid spending time finding op-
timal settings. Calculating func-
tions for waveform analysis in-
clude adding, subtracting, multi-
pying, dividing, offsetting, inte-
grating, differentiating, or
smoothing test and measurement
data.

The menu-driven software runs
on MS-DOS 2.1 or higher. It is writ-
ten in C and executes all functions
quickly. It is priced at $450.00.—
Tektronix, Inc., P.O. Box 500,
Beaverton, OR 97077.



ANTENNA SWITCH, the model

MFj-1701, has six positions that en-
able the user to switch antennas
with the turn of a knob. It has
SO-239 connectors and there is
negligible insertion loss, as well as
low VSWR and low crosstalk be-
tween adjacent outlets. All unused
terminals are automatically
grounded for static/lightning/RF
protection.




CIRCLE 22 ON FREE INFORMATION CARD

The model MFj-1701 can be used
with 52- to 75-ohm systems, and it
can be mounted with equal ease
on a desk or on a wall. In addition,
it handles 2000 watts SSB, 1000 CW.
It is priced at $29.95, plus $5.00
shipping and handling. — MFJ En-
terprises, Inc., P.O. Box 494, Mis-
sissippi State, MS 39762.

DIGITAL MULTIMETER, model
4800, can measure DC and AC volt-
age and current, resistance, fre-
quency (channel A, 10 Hz to 100




CIRCLE 23 ON FREE INFORMATION CARD



MHz; channel B, 10 Hz to 1000
KHz), period, dBm, diode test,
continuity test and temperature
(with K-type thermocouple). Also



38



ELENCO PRODUCTS AT DISCOUNT PRICES!





-






? -



-



20 MHz DUAL TRACE OSCILLOSCOPE
$329 MO-1251



35 MHz DUAL TRACE OSCILLOSCOPE

$545 MO-1252



Top quality scopes at a very reasonable price. Contains all the desirable features. Etenco's 2 year guarantee
assures you of continuous service. Two 1x, 10x probes, diagrams and manual included. Write for specifications.




MULTI METER with

CAPACITANCE and

transistor tester



s,



65



Model
CM-1500




TRUE RMS 4V4
DIGIT MULTIMETER



135



Model
M-7000



Reads Volts, Ohms,
Current, Capacitors
Transistors & Diodes



GF-8016 Function Generator
with Freq, Counter

$

? Sine, Square, Triangle,
?Pulse, Ramp, .2 to 2 MHz

? Frequency .1 thru 10 MHz

GF 8015 without Freq. Meter 169



.05% DC Accuracy
.1 % Resistance
with Freq. Counter
& Deluxe Case






3V2 DIGIT
MULTIMETER



! 25



Model
M-1600



1% DC Accuracy
1% Resistance
Reads 10A DC




Triple Power Supply XP-660

" " $1 4950

0-20V @ 1A

O-20V @ 1A

5V @ 5A

Fully Regulated, Short Circuit Protected with 2
Limit Cont. 3 Separate Supplies.

3 Amp Power Supply XP-650

$11950

0-40V @ 1.5A
0-20V @ 3A



POWER BLOX

The Power Supply For Breadboarding



Wh-



%



■i 495



$



995



pro-






Fully regulated, short circut protected current
limit control



Now a Power Supply for your Bread Blocks. Snaps in
to existing units. Fully regulated and short circuit pro
tsctsd

12V @ .3A, 5V @ 1A, -5V @ .5A

?22 .95 for Both, Power Blox & Breadboard



DIGITAL LCR METER

Model LC-1 800 * . m 0%

Measures: Inductors 3>1 f\ M
Capacitors, Resistors I ^W

Inductors .1^Hto200H
Capacitor. 1 P/ to 200^/
Resistor .01Qto20MQ
Ranges 6 Ind, 7 cap, 7 res




C&S SALES, 8744 W. North Ter. Niles, IL 60648

800-292-7711 (312)459-9040 3HEI VmM BACK GUARANTEE ASK FO,

2 Year Limited Guarantee! Add 5% for Postage ($10 max.), IL Res., 7% Tax



SB



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BACK GUARANTEE



CIRCLE 266 ON FREE INFORMATION CARD



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included are comparative, data
hold, peak hold, relative, and
auto-ranging functions. The 5-dig-
it LCD display indicates pushbut-
ton-selected functions and low
line voltage and overrange condi-
tions.

The mode! 4800 provides multi-
ple-fuse overload protection and
recessed lead jacks. Accessories
include: power cable, spare fuses,
signal cable, alligator test leads,
and a comprehensive instruction
manual. Optional accessories in-
clude various K-type thermocou-



ples, bench "hold" probe, and 10-
amp measurement probe.

The model 4800 is priced at
$600.00.— Triplet! Corporation,
One Triplett Drive, Bluffton, OH
45817.

REMOTE-PROGRAMMABLE VCR,

the model VR4100, is designed to
deliver sharper pictures, more nat-
ural colors, and less video noise.
Its features include a 14-day, eight-
event timer that can be pro-
grammed, using an onscreen dis-
play, with the VCR's infrared



How to service and repair your

television, VCR, and home

computer.

Sams PHOTOFACT and COMPUTERFACTS



For 40 years Sams PHOTOFACT has been the preferred source for television
service data. Today. Sams is the preferred source for VCR, computer, and
computer peripheral service data. Why? Because Sams service data is
accurate, reliable, provided in a consistent format, arid available at a very
reasonable price. With more than 150,000 different models, you can depend
on Sams (o have the service data you need.

Sams works from actual production models, disassembling each unit and
testing each board. Every component location, every circuit track, and every
waveform is checked and rechecked. Sams exclusive time-saving features let
you do repairs quickly, without guessing:

? CAD-Generated Schematics — our computer-aided design system
gives you clear, readable data in Sams Standard Notation format.

? GridTrace? — a "roadmap" grid in our circuit board photos for easy
parts location and identification.

? CirculTrace 3 —helps to pinpoint circuit location saving tracking time.

? Troubleshooting Tips — solve problems without trial and error.

? Easy-Read Waveforms — clear reproductions of actual waveform
photos show you exactly what your test waveform should look like,

? Replacement Parts Cross References — save costly and time-
consuming trial and error.

At $9.95 for PHOTOFACT and $19.95 or $39.95 for COMPUTERFACTS

you get all the data you need to service your equipment.



To order call

800-428-SAMS

Ask for operator 807

In Indiana call 317-287-5566



sms-




Here's just a few of the brands covered:
PHOTOFACT COMPUTERFACTS



Curtis-Mathes


Amdek


Magnavox


Apple


Panasonic


Commodore


RCA


Epson


Sears


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1



I



IT



8830 N. Milwaukee Niles, IL 60648




-?0-Sf



IK



IHaKv

Kirlian
Photograph



:



wis an



JOHN I0V1NE







In this article we explore the mysteries

ol Kirlian photography and show you how you can

investigate the phenomenon yourself!



LABORING IN RELATIVE OBSCURITY, Sl-.YMON Klkl.lAN (l>RO-

nounced keer-lee-an) began his work in electrophotography in

1939. Over 40 years later, that work is still the source of much
speculation and controversy. That's because it bus been claimed
that Kirlian was able to use auras lh;it surround the subjects in his
electrophotographs to detect illness in plants anil animals hefore
any other outward symptoms were visible. True or not. those
claims sparked a ureal deal of interest in the (ield of elec-
trophotography: so much so that electrophotography is today
commonly called Kirlian photography.

What is it?

In Kirlian photography a high-frequency, high-voltage source
is used to produce images on photographic Him. It does so
without the benefit of a camera, lenses, or light, so it can, in
some ways, be likened to X-ray photography.

The only thing that is known lor certain about the Kirlian auras
is that they exist. The nature of those auras is the subject of much



conjecture.

Many of the theories used to explain the effect read like



excerpts from a science- fiction novel. One theory is that all
substances, and in particular living organic matter, contain and
are surrounded by what can be described as a matter-energy
held. When a high-frequency, high-voltage charge is introduced
in that field, it becomes, or behaves like, a superconductive
plasma. The laws of physics lhat govern such a plasma are
complex, involving an extended form of l-jiistien's Theory of
Relativity. The aura that surrounds objects in Kirlian pho-
tographs then might be that plasma.

Whatever the nature of the auras, Kirlian photography is



getting some serious attention in some very serious places. And
the U.S. government has even gotten into the act— one of the
leaders in the investigation of the Kirlian aura was the Bio-
chemistry Laboratory at the Naval Air Development Center, in
Warminster PA. (Unfortunately, that unit is now disbanded).

While a great deal of research has already been done on the
subject, a great deal more still needs to be done before we'll
know for certain what Kirlian auras are. and whether or not they
can be useful in some applications. Nonetheless, those images
have been used experimentally as diagnostic tools in medicine



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DC

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and for non-destructive testing of mate-
rials in engineering.

One interesting aspect of Kirlian pho-
tography is that while all objects appear to
have a Kirlian "aura," the aura of inani-
mate objects appears to he constant over
time, while living creatures give off an
aura that is time-varying. In humans,
emotional stress, illness, and consump-
tion of alcohol or drugs all appear to have
an effect on the aura.

One of the U.S. government's studies
in the area involved using the Kirlian aura
to ascertain the physical and mental health
of military personnel, and to determine
their level of fatigue. That was done by
measuring the diameter of the Kirlian
aura, or corona, at the fingertip. At the
end of the test, the results were analyzed
and two statistically valid conclusions
could be drawn. One was that the corona
of those suffering physical stress (exer-
cise) was larger in diameter than the test
average; the other was that those suffering
mental stress (fatigue, etc.) had Kirlian
coronas that were smaller in diameter than
the test average.

While the results of that test were inter-
esting, there is still not enough data to hail
Kirlian photography as a "fool-proof" di-
agnostic tool . Although other si mi lar tests
have been reported, the results have been
incomplete. For instance, in one study,
the fingertip coronas of 120 adult humans
were photographed. Of the sample, 20%
had a corona diameter that was markedly
below the average. Of those, 50% it was
later determined suffered from some sort
of medical problem.

There are several obvious Raws with
that study. For one, no report was made on
the health of the 80% whose corona diam-
eter was not reduced; it would have been
informative to know what percent if any of
those also suffered from some medical
problem. Also, no follow-up appears to
been done on those whose corona diame-
ters were decreased and who had no ascer-
tainable medical problems. It would have
been interesting to see how many of those
later developed some type of difficulty,
and in what time frame following the ex-
periment.

One of the most dramatic experiments
in Kirlian photography, and one of the
ones that has garnered the most attention,
is the so-called phantom leaf experiment.
In that experiment, a small part (approx-
imately 2% to 10% of the total surface are)
is cut off. Kirlian photographs subse-
quently taken will sometimes show the
energy pattern or aura of the missing sec-
tion. The reason for that is unknown, and
the subject of much speculation, but al-
though the effect is exceptionally rare, it
has been demonstrated enough times to
prove its existence. There have even been
studies attempting to correlate the ancient
art of accupuncture and the auras seen in
Kirlian photographs.




FIG. 1— YOU CAN MAKE YOUR OWN Kirlian photographs using this circuit. Coil L1 is an automotive
Ignition coil that can be obtained cheaply from almost any automotive junkyard.

Making your own

There are probably quite a few doubters
still out there. To those we offer the fol-
lowing challenge: Why not build your
own Kirlian photography unit and prove
or disprove the existence of the effect to
yourself? In the balance of this article we
will present a simple set-up that will allow
you to do just that. Although the equip-
ment is not on a par with those used in
research labs, it is still more than suffi-
cient to provide startling results. The color
photographs that accompany this article,
showing the Kirlian aura of some com-
mon leaves, were produced using the ap-
paratus described.

The circuit for the set-up is shown in
Fig. I . The heart of the circuit is a simple
oscillator whose output is fed to a stan-
dard 12-volt, three -terminal automotive
ignition coil, LI.

Construction is straightforward, and
the circuit is simple enough that a PC
board is not required, although one can be
used if you wish. Note that the transistors
can get pretty hot, so they should be ade-
quately heat sinked. The only other point
that merits special mention is that if a
metal chassis is used, special care should
be taken to isolate the circuit from the
chassis. Otherwise a serious shock hazard
could exist.

To further minimize the potential for
shock, the ignition coil, LI, should be
housed in its own non-conductive chassis.
One suitable chassis is shown in Fig. 2. It
is fashioned from a cardboard tube, such
as those large rolls of gift-wrap paper
come on; the ends are circular pieces of
plexiglass.

Figure 3 shows the construction details
of the coil chassis. The ignition coil is
mounted by simply gluing it to one side of




FIG. 2— THE "CABINET" for L1 can be fashioned
from a cardboard tube. The endcaps can be
made of plexiglass.

the tube so that the high- voltage terminal
will protrude slightly when the end caps
are installed. A ground lead is provided by
soldering a wire to the body of the coi l : the
other end is terminated in a case-mounted
binding post. Note that the inputs from the
main part of the circuit enter the coil chas-
sis from the rear and are routed along the
body of the coil through a length of plastic
tubing. That tubing is used to insulate the
leads from the body of the coil. Although
the coil could be hard- wired to the bal-
ance of the circuit, the use of plugs and
sockets allows for greater convenience.
Further, the use of the polarized con-
nectors mentioned in the parts list elimi-
nates the guess work when reconnecting
the circuit.
Three-terminal ignition coils can beob-



44




FIG. 3— THE AUTOMOTIVE IGNITION COIL is mounted Inside its cabinet by gluing it to one side. Make
the ground connection by soldering a wire to the side of the coil housing and connecting the other end
to the cabinet-mounted binding post.



SPECIMEN



.010 INCH

TRANSPARENT

PLASTIC




COPPER CLAD BOARD
(SEE TEXT!



I

+V



FIG. 4— THE SPECIMEN TO BE PHO-
TOGRAPHED should be sandwiched between
two sheets of thin (.010-inch) transparent plas-
tic.

tained from any automotive supplier. A
much cheaper alternative is to pay your
local automotive junkyard a visit, A coil
can be obtained there for as little as $5.00.
Just about any 12- volt, three-terminal ig-
nition coil will work, so get the least ex-
pensive one you can.

There is nothing particularly exotic
about the parts required and most can be
obtained from your local supplier. With
some careful shopping, total cost should
not exceed $60 . 00 or so . If you have a well
stocked junk box, that cost can be reduced
further. If you wish, complete kits, as well
as wired and tested units can be purchased
from the supplier mentioned in the Parts
List.

The set-up used in making a Kirlian
photograph is shown in Fig. 4. The bot-
tom plate is made from a single-sided
piece of copper-clad PC-board material.
The board should measure at least 4x5
inches so that standard 4- x 5 -inch sheet
film can be accommodated; more on the
film in a moment. That plate is placed
inside a thin, transparent plastic bag, cop-
per side up, the bag is taped to prevent



PARTS LIST



R1 — 25,000 ohms, potentiometer
C1— 220 u.F, 35 volts, electrolytic
C2— .022 u.F, polyester film
Q1— TIP3055 NPN transistor
Q2— MJE34 PNP transistor
BR1 — 1.5-amp, 50 PIV full-wave bridge
rectifier (Radio-Shack 276-1151 or
equivalent)
NE1— neon-lamp assembly (Radio-
Shack 272-704 or equivalent)
S1, S2— SPST pushbutton switch
T1 — 11 7- volt primary, 25-volt 450- m A sec-
ondary (Radio-Shack 273-1366 or
equivalent)
L'1— three -terminal, 12- volt, automotive ig-
nition coil
Miscellaneous: Case; case for ignition
coil; perforated construction board, PC
board, or prototyping board; single-sided
copper-clad board; polarized plugs (Ra-
dio-Shack 274-201 or equivalent); polar-
ized sockets (Radio-Shack 274-202 or
equivalent); heat sinks for transistors;
strain relief; power cord; knob for R1 ; wire;
solder, etc.

A kit of all parts, including connectors,
cords, cases, and prototyping board
(no PC board is available) is available
from Images Co., PO Box 313, South
Richmond Hill Station, Jamaica, NY
11419. The cost is S90.00. A wired and
tested version is available for $125.00.
Add $2.50 for shipping and handling.
NY residents add 8'/?% sales tax.

slippage, and a piece of the photographic
film is placed upon it. If the specimen to
be "photographed" is inanimate, such as
a plant leaf or a piece of metal, it should
be grounded (connected to the ground ter-
minal on the coil chassis) for best results
(see the important note that follows). In
any event, the specimen is placed between
two sheets of thin (.010-inch) transparent



plastic, and the "sandwich" is then
placed on the film. The copper-clad board
is connected to the high-voltage terminal
of LI via a length of wire.

Important! Never, never ground a
living creature, including yourself.
Doing so can subject that "specimen" to a
very nasty shock. When dealing wilh liv-
ing creatures, take special care to prevent
any contact with ground.

One note about the ignition coil's high-
voltage terminal: To the uninitiated, the
location of that terminal may not be appar-
ent at first glance. It is located within the
tube- like protuberance at the top of the
coil housing. When the coil is used in its
normal application, a heavy-gauge spark-
plug wire is placed in the opening at the
top of the tube so that it contacts the termi-
nal inside; the wire is held in place by
friction. For our application, the lead
from the copper-clad board must be
placed within the terminal opening such
that a sure contact with the high-voltage
terminal is maintained at all times.

You will note from Fig. 1 that the circuit
uses two on/off switches, SI and S2.
Switch SI is the unit's main power switch;
when it is in the on position, power is
supplied to the neon lamp, NE1, and the
circuit is placed in the stand-by mode.
The neon lamp does more than give a
visual indication of the state of the unit.
Since we will be working with pho-
tographic film, the circuit must be used in
a relatively dark, light-tight room. Ob-
viously, that can present problems in
using the unit (you can't use what you
can't see). If the controls are clustered




FIG. 5— TO MAKE THEM EASIER TO FIND in the
dark, cluster the unit's operating controls
around NE1.



about the lamp (as shown in fig. 5), the
lamp gives off just enough light to make
identification of the controls possible in a
dark room without adversely affecting the
film. Switch S2, the discharge switch,
is used to control the operation of the
balance of the circuit.

To make a Kirlian photograph, turn on

the unit using SI , turnout the lights, place ^

the film and the specimen on the electrode -<

as discussed previously, and make the ex- ?

continued on page 94 o>



45



m






Click and Pop

^ Filter for your

STEREO




JOE GORIN



By eliminating unwanted pops, clicks and other

surface noise, this inexpensive scratch filter brings you to new heights of audio realism!



THE PROLIFERATION OF D1GITALLY-MAS-

tered record albums might make you think
that surface noise is a dead issue.
However, even the best modem pressings
contain some amount of noise, and, even
with scrupulous care, all vinyl recordings
deteriorate with age.

You might think that you could avoid
the surface-noise problem by buying only
compact discs (CD's), which suffer none
of the problems endemic to vinyl record-
ings: hiss, rumble, clicks, and pops.
However, many new recordings are un-
available on CD, and thousands of al-
ready-released recordings may never be
re-issued on CD. So, if you're after the
utmost in high-fidelity sound reproduc-
tion, you'll want to build our scratch elim-
inator. It's easy to assemble, and it
requires no alignment. Just plug it in and
give your ears a treat!

Why it works

Since commonly-available stereo
equipment easily achieves distortion lev-
els below 0.1%, you might think that
chopping up a musical signal to delete an
occasional scratch would be foolish be-
cause of the distortion it would add.
However, we have found that even the sim-
plest scratch filters produce a notable im-
provement in sound quality. The reason is
simply that the human ear responds slow-
ly to fast-changing audio signals. One in-
dication of that slowness is the fact that
even the best magnetic tape has numerous
dropouts of a greater duration than most



scratch deletions — and tape dropouts are
seldom noticeable. So deleting a scratch
in the midst of a complex musical passage
is easily done with no noticeable effect.

The real problem is this; What happens
when a large musical transient (like a
cymbal crash or closely-miked plucked
strings) occurs? Wouldn't it be deleted
and thereby take the "bite" out of the
transient? The answer is no, given the
right design. High-energy musical tran-
sients might trigger the detector, but the
deletion should be inaudible because the
transient usually lasts at least 50 ms,
whereas the deletion lasts foronly 0.5-1 .0
ms. The ear can't react that fast, so the
deletion is inaudible.

The human hearing system reacts to
transient signals according to a parameter
called the "pitch recognition interval."
For most frequencies, that interval is
about 10 ms. If a signal lasts much less
than 10 ms.it sounds pitchless or atonal —
you cannot identify its tone. So all very
short signals sound like clicks. Musical
instruments are designed to make pleas-
ing sounds, so they have decay times long
enough to get them through the pitch rec-
ognition interval. So even if you delete a
fraction of a tone at the beginning of a
transient, the tone will still sound natural.

You may find it interesting to know that
one commercially-available scratch filter
uses the "click" effect to mislead the lis-
tener intentionally. That filter has an in-
vert button that is used to "evaluate" the
unit. In invert mode, only the shortened



deletion intervals are passed on to the
speakers, rather than the source signal.
The listener is impressed by all the click-
ing, but he really has no way of knowing
whether it's triggered by high-energy mu-
sical transients or by surface noise.

The point is that pops and clicks can be
eliminated, so the question is, how? The
answer is somewhat complicated, so let's
step back for a moment and examine other
ways of cleaning up the sound of vinyl
disks.

Noise-reduction techniques

Essentially, there are three methods of
improving the quality of any pho-
nographic recording:

? Noise filter/expander

? Rumble filter

? Scratch filter

A noise filter serves to remove broad-
band, high-frequency noise, and an ex-
pander helps restore the original dynamic
range with which most music is per-
formed, if not recorded. The theory be-
hind those signal processors was covered
in depth in the author's articles in the
January and February, 19S1 issues of Ra-
dio-Electronics; the March and April is-
sues of that same year carry a two-part
construction story that details building a
noise filter/expander.

A rumble filter removes subsonic sig-
nals (less than 20 Hz), and combines
somewhat higher frequencies (ranging
from 100 Hz to 200 Hz) into a monaural
signal. Doing that reduces noise without



46



reducing intelligible program material.
For more information on rumble filters,
consult the author's article in the
November, 1981 issue of Radio-Elec-
tronics. That article describes con-
struction of a rumble filter. Kits for both
the noise filter/expander and the rumble
filter are still available from the source
mentioned at the end of this article.

Of the three phonographic noise- reduc-
tion techniques the first is probably the
most useful for discriminating au-
diophiles. The second is good for au-
diophiles whose systems have extended
bass response and who have already elim-
inated most noise with a noise filter. Last,
a scratch filter can help reduce unwanted
noise from any phono system, and it will
be particularly useful to people with large
collections of old records. With that under
our belts, let's find out how to build a
scratch filter.

Circuit operation

As the block diagram in Fig. 1 shows,
the basic idea behind a scratch eliminator
is simple. By delaying the input signal for
a short time (about 40 microseconds), the
detector can "see" a scratch before it




FIG. 1— THE ESSENCE OF THE FILTER is the
delay unit that allows the deleter to remove high-
energy transients like pops, clicks, and
scratches before they have a chance to reach
your ears.

reaches your amplifier. The detector acti-
vates a switch that prevents the input sig-
nal from passing through to the output.
The switch remains open for the short
time that the scratch is present, usually
100-200 microseconds, but sometimes as
much as a millisecond, or even more. And
rather than leaving a '"hole" in the output
sound, it would be nice if the deletercould
substitute the signal that would have been
there, had there been no scratch.
From an engineering point of view, it's



easy to design the delay unit. The delay
unit's function is simply to delay all fre-
quencies of interest by 40 microseconds
or more. In the process, it should not
change the amplitude of any frequency
beneath 20 kHz (the limit of human hear-
ing). The circuit may, however, reduce the
level of higher frequencies. Delay is ac-
complished by phase-shifting the input
signal and sending it through a low-pass
filter.

As shown in Fig. 2, the first three op-
amps in each channel, along with their
associated passive components, perform
the low- pass filtering and phase shifting.
We'll talk about the right channel, but
bear in mind the fact that the left channel
functions identically. Incidentally, corre-
sponding components in the left and right
channels are numbered offset by a value of
100. For example, R101 in the right chan-
nel corresponds to R201 in the left.

Capacitors CI01, C102, and
C104-C106 and associated resistors
provide low-pass filtering. They pass the
audio signal, provide some phase shift,
and attenuate ultrasonic signals. In addi-
tion. C10! and C105 add controlled
amounts of positive feedback to help re-



PARTS LIST



All resistors ' 4-watt, 5% unless noted.
R1-R4, R11, R12, R26, R54, R102, R103,

R11S, R202, R203, R218— 22,000

ohms
R5, R107, R207— 2400 ohms
R6— 7500 Ohms
R7, R24—4700 ohms
R8, R9, R14, R43, R44, R50. R51, R114,

R115, R214, R215, R301-R 304— 1000

ohms
R10, R34, R35— 150,000 ohms
R13— 150 ohms
R15— 1200 ohms
R16, R39, R56, R104. R204, R305,

R306— 2200 ohms
R17, R18, R25, R29. R30, R37, R38—

10,000 ohms
R19 — 4.7 megohms

R20, R57. R59, R121, R221— 560 ohms
R21— 470 Ohms
R22, R106. R206— 1800 ohms
R23— 68,000 ohms
R27. R60— 180,000 ohms
R28— 3300 ohms
R31— 330,000 ohms
R32— 220 ohms
R33— 15,000 ohms
R36— 470,000 ohms
R40, R49, R62-R100, R123-R200,

R223-R300— not used
R41, R46— 39.000 ohms
R42— 22 megohms

R45— 100,000 ohms, linear potentiome-
ter
R47, R101, R201— 100,000 Ohms
R48, R61, R122. R222— 270,000 ohms
R52, R116. R216— 36,000 ohms



R53, R58, R111, R117, R211. R217— 6200

ohms
R55, R119, R21 9— 91.000 ohms
R105, R205— 100 ohms
R108, R208— 2700 ohms
R109, R209— 3000 ohms
R110, R210— 12,000 ohms
R112, R120, R212. R220— 33,000 ohms
R113, R213— 8200 ohms
R307, R308— 22 ohms
Capacitors
CI. C15. C16— 0.0033 pF, 10%, polyester

film
C2, C5, C20, C22, C107-C109,

C207-C209— O.001 pF, 10%, polyester

film
C3, C4. C8, C24, C111. C113, C211, C213,

C305, C306, C308— 10 p.F, 25 volts,

aluminum electrolytic
C6, C7. C14, C18, C103, C203— 0.033 p.F,

10%, polyester film
C9 — 3.3 (iF, 35 volts, aluminum elec-
trolytic
C10-C12, C301— 0.1 p.F, 10%. polyester

film
C13, C17, C23, C25. C26, C110, C112,

C210, C212— 0.01 pF, 10%, polyester

film
C19, C21— 680 pF, 10%, ceramic disc
C27— see text
C28-C100, C114-C200. C214-C300—

not used
C101 . C201— 330 pF, 10%, ceramic disc
C102. C106, C202, C206— 220 pF, 10%,

ceramic disc
C104, C204— 0.0047 p,F, 10%, polyester

film



C105, C205— 0.022 |aF, 10%, polyester
film

C302— 1000 p.F, 35 volts, aluminum elec-
trolytic

C303, C304— 1000 p,F, 25 volts, alumi-
num electrolytic

C307, C309 — 0.1 p-F, ceramic disc

Semiconductors

IC1-IC3, IC5— RC4136, quad op-amp

1C4— LM301A. op-amp

IC6— LM393, op-amp

IC7, IC8— 4016, quad analog switch

Q1, Q2— 2N3904, NPN transistor

D1-D10— 1N4148, switching diode

D301-D304 — 1N4002, power diode

LED1— standard LED

Other components

J1-J8— RCA Phono Jacks

SI, S2— DPDT toggle Switch

Note — The following parts are avail-
able from Symmetric Sound Systems,
Inc., 856 Lynn Rose Ct, Santa Rosa,
CA 95404, (707) 546-3895: Complete
Kit (No. PS-1) S79.95; PC Board (No.
PS-1PC) $12.00; Ail semiconductors
(No. PS-1SC) $13.00: All resistors and
capacitors (No. PS-1RC) $16.00; Trans-
former (No. PS-1XF) S7.50; Chassis,
endpanels, switches, hardware, jacks
and instructions (No. PS-1ETC) $42.50.
Free UPS shipping in U.S. with check;
MasterCard and Visa orders must add
shipping. PS-ISC, PS-1RC and
PS-1 ETC will not be available after Jan-
uary 31, 1987. California residents
must add appropriate sales tax.



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FIG. 2— THE CIRCUIT OF THE SCRATCH FILTER is shown here. Note that components numbered from
0-99 refer to the detector circuit, 100-199 refer to the right channel delay/delete section, and 200-299
refer to the teft channel. The triangular symbols here provide a separate "ground" reference for the
detector circuit.



+ 10dB









A














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i


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so no r


70










TIME-(ls a FREQUENCY-KHZ

s B b

FIG. 3— TIME- AND FREQUENCY-DOMAIN responses of the Filter are shown here. Note that the circuit
doesn't respond before at least 40 |is have passed, and that output is flat {within to dB) to 20 kHz,



spotise. Further, the network formed by
C107 and C108 functions as an "all-pass"
network that provides lots of phase shift
with little change in amplitude.

Our circuit was simultaneously com-
puter-optimized for both its frequency-do-



main response, which is flat to 20 kHz,
and its time-domain response: no reaction
to a triangular, scratch-like pulse for at
least 40 microseconds. Figure 3-a shows
the time-domain response curve, and Fig.
3-h shows the frequency-domain response



curve. The latter is presented with both
ideal and actual curves; you can see that
the actual output is flat within Vi dB all the
way to 20 kHz.

Scratch deleter

The deleter has a somewhat more diffi-
cult task to accomplish than the delay/
phase-shift network. In addition to com-
pletely blanking out the scratches found
by the detector, it should replace the de-
leted signal with a signal that sounds as
little as possible like a scratch, and as
much as possible like the original pro-
gram material, had there been no scratch.
Since the circuit can't know what that
signal was, it must predict it.

Actually, the deleter's first job is ac-
complished in the input circuitry dis-
cussed above. A 75-microsecond pre-
emphasis is provided by R104, R105 and
CI 03. That pre-emphasis boosts audio
signals above the corner frequency of



48



2122 Hz. Explaining the need for that pre-
emphasis requires a lengthy digression.

The RIAA curve

In order to optimize signal-to-noise
ratio, phonograph sound-reproduction
systems are designed to operate with pre-
emphasis at the recording end and de-
emphasis at the playback end. The play-
back response used in your phono pre-
amplifier is the RIAA (/? ecord /ndustry of
America Association) curve shown in Fig.
4. That curve is designed to respond cor-



rectly to the output of a magnetic car-
tridge. Most high-quality cartridges are
magnetic, and the output of a magnetic
cartridge is a voltage that is proportional
to the velocity of the stylus.

Since higher frequencies have higher
velocities for the same amplitude, a ve-
locity transducer effectively imparts a 6-
dB /octave treble boost over the entire
bandwidth. The resulting signal is shown
in Fig. 5. Because of that treble boost, the
circuit stores energy and releases it slow-
ly. If a pulse of displacement (change in



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FIG. A — THE RIAA DE-EMPHASIS curve necessary for processing signals from standard magnetic























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FREQUENCY-Hz
FIG. 5— OUTPUT OF A STANDARD MAGNETIC CARTRIDGE increases at a rate of 6 dB/octaveover the
audio frequency range.



































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FREuUEMCY-Hz
FIG. 6— OUTPUT OF A MAGNETIC CARTRIDGE SHIFTS when the stylus encounters a deformation in
the vinyl surface.



position from center) occurs on the rec-
ord, as shown in Fig, 7-a, the response
exhibits a settling tail that decays expo-
nentially with a time-constant of 75 mi-
croseconds. The breakpoint in the curve is
at the reciprocal of 2ji x 75 microse-
conds, or 2122 Hz.

Because of that settling time, deleting a
scratch can be tricky. If the deletion time
isn't long enough, some scratch energy
may pass through as noise. But if the
deletion time is too long, a distracting
audible "hole" would be created.

Our solution is to pre-emphasize the
signal before it reaches the deleter. Doing
that would cause an input signal like that
shown in in Fig. 7-a to appear as in Fig.
1-b. A pulse (or scratch) input would ap-
pear as in Fig. 1-c. Observe that, although
the pulse is larger, it is now constrained to
a much shorter period of time.

Pre-emphasis is desirable for another
reason besides the elimination of settling
tails. The treble boost caused by pre-em-
phasis reduces the number of scratch-pre-
diction errors in the deleter.

The deleter

The deleter is the last op-amp stage in
each channel (IC3-a). Its operation is con-
trolled by the two analog switches IC7-a
and IC8-a, The op-amp in conjunction
with R116 and C109 forms an integrator.
When the switches close, R114 and 115
apply negative feedback to the integrator.
The result is a filter with a de-emphasis
comer at the desired 2122Hz.

If that were the entire circuit, when a
deletion occurred, the charge stored by
feedback capacitor CI 09 would cause it to
act as a sample-and-hold circuit, which
works well for short deletions during low-
frequency waveforms. However, several
components are added to the deleter that
improve its operation in two different
ways.

First, just before the deletion begins,
capacitor CI 12 stores the input waveform
by charging to the voltage at R 116. Then,
when the deletion begins, switch lC7-a
opens. That prevents the signal from the
previous stage from getting to lC3-a, so
the voltage across CI 12 is fed through to
the output, and that keeps the output at a
level approximately equal to the level just
before the scratch.

That improves low-frequency perfor-
mance, but it doesn't help high frequen-
cies at all. However, that's OK, because,
even though low-frequency signals mask
deletion-errors poorly, high-frequency
signals mask deletion well.

To prevent CI 12 from storing high-fre-
quency signals, RI 17 limits the charge
that can build up on CU2. If that charge
extended over more than a fraction of a
cycle, it could cause severe errors in ihe
deleter. When a deletion occurs, R 1 18 and
switch ICS-a discharge CI 12 rapidly so
that the slope estimated by CI 12 isn't



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TIME
FIG. 7— EXPONENTIAL DECAY of an Input Sig-
nal (a) is lengthened by pre-emphasls (o). Addi-
tional p re-emphasis increases the amplitude,
but decreases the duration of a scratch (c).

over-corrected. Capacitor CI 11 prevents
IC3's outputs from causing switching
transients when IC8-a changes state. Re-
sistor R119 does the same thing for the
leakage currents in the switch.

The second means by which the deleter
is improved is through the combination of
R122 and CI 10. If the deletion lasts long
enough, the sample-and-hold and slope-
extension techniques become ineffective.
We guard against that condition by using
C110 to store the long-term average of the
input signal. So, after a long deletion,
C110 re-charges CI 09 to that average volt-
age, and that prevents the audible "holes"
mentioned above from marring the output
signal.

Glitch cancellation

The combination of sample-and-hold-
ing, slope extension, and long-term-aver-
age circuits makes most deleter errors
inaudible. However, there is another
source of error: the signal required to turn
the switches off and on. Although that
signal is 14- volts p-p, ideally the error at
the integrator output is less than I mV, a
ratio of "14.000/1. Since C109 is 1000 pF,



the capacitor that couples the switching
waveform intoC109 must be 1000/14,000,
or about 0,07 pF — a very small amount.
That's achieved by circuit and layout
matching.

Circuit matching works by using lC3-c
and associated components to duplicate
the deleter stage. We call the duplicate the
"example" circuit. When the switches
change state, they inject transients into
the example circuit. Then lC3-d com-
pares the output of the example circuit to
ground, and it injects the opposite signal
into ihe "glitch injection" terminal of the
example circuit, the non-inverting input
(pin 13) of IC3-c. That forces the output
back to zero volts via negative feedback.
The glitch output is also connected to the
non-inverting inputs of each channel's de-
leter circuit, and that cancels glitches
there too.

Performance is also increased by using
matched parts (they're matched in that
they're fabricated on the same 1C chip) for
the switches and op-amps in the deleter
and example circuits. In addition, great
effort has been expended toward making
the layout of each channel identical. Fur-
ther, we added guard traces between sen-
sitive IC pins, and the legs of some critical
resistors are specially formed to match
each channel's pickup of the switching
signals.

The detector

The detector circuitry consists of three
parts: a differential amplifier and filter, a
full- wave detector with ALC (Automatic
Level Control), and a comparator with
masking-threshold setting. Note that the
detector circuit's ground is raised above
the main chassis ground by R308 to mini-
mize noise pick-up.

"The differential amplifier is formed by
[Cl-d. It is used to detect scratches, which
are 180° out of phase between the two
channels. The reason they're out of phase
is that the surface of a disk that has had
vinyl removed causes a negative-going
pulse in one channel, and a positive-going
pulse in the other. Hence ICl-d is config-
ured to respond to the difference between
the two channels. Next, CI, C2, R5, and
R6 form a high-pass filter that passes only
the highest audible frequencies, as well as
any ultrasonic signals.

The reason for passing the high audible
frequencies is that, although the energy in
most scratches rolls off slowly above 10
kHz, the energy in music rolls off much
more rapidly, but that roll -off starts at a
lower frequency. Thus, the "noise-to-sig-
nal" ratio is higher in the ultrasonic fre-
quency region. Also, the vinyl that
normally contacts the stylus damps the
mechanical resonance of the stylus. But
during a scratch, that resonance (usually
at 20-30 kHz) is excited, and damping
decreases because the stylus loses contact
with the groove.



The full-wave detector (with ALC) is
composed of QI, Q2, IC4, IC5-cand IC5-
d. The base of Ql is biased at the detector
reference, so the currents flowing through
Ql and Q2 is controlled by the voltage
applied from lC5-d. Hence, those devices
form a current-controlled attenuator
whose output is fed to IC4, an LM301A
op -amp.

Normally the LM301 requires 30 pF of
capacitance between pins 1 and 8 for sta-
bility. That capacitance completes an in-
ternal negative-feedback loop that rolls
off the gain at high frequencies and keeps
the op-amp stable.

There is, however, internal positive
feedback due to the capacitance between
pins 5 and 6. That capacitance subtracts
from the capacitance that exists between
pins 1 and 8.

Wc want to use a very small stabilizing
capacitor — 0.3 pF, implemented with PC
traces — so we must reduce that positive-
feedback capacitance by clipping pin 5 of
the op-amp. That results in a op-amp with
a 100-MHz gain-bandwidth product.

The LM301 amplifies the signal by a
factor of 150. Positive half-cycles flow
through Dl , and negative half-cycles flow
through D2; those signals arc then applied
to IC5-c. another differential amplifier.
The signal from Dl is fed to the non-
inverting input, and the signal from D2 is
fed to the inverting input. Since both
positive and negative half-cycles appear at
IC5-c's output as positive- going, IC5-C is
a full -wave rectifier.

The ALC loop is closed by IC5-d and
associated components. Resistor R21
provides a 100-mV voltage reference. Re-
sistors R24, R25. and capacitor C9 con-
figure IC5-d as an integrator, so if IC5-c"s
output averages more than 100 mV, the
integrator goes negative. That increases
the current through Ql and Q2, so the
signal level is reduced via negative feed-
back. Because the voltage-current rela-
tionship is exponential, the ALC loop has
a bandwidth (or readjustment rate) that is
independent of signal level.

The human ear's sensitivity to scratch-
type noise varies with signal level; it is the
job of the ALC loop to simulate that varia-
tion. That makes the front-panel sen-
sitivity adjustment less critical.

The comparator, lC6-a, is the last sub-
section of the detector. Recall that the
output of IC5-c is the level-controlled,
full- wave- rectified, high-frequency ver-
sion of the difference between the right
and left channels. If we compared the
junction of R22 and R23 to ground, the
comparator would register a scratch any
time the level there exceeded five times its
recent average level, so additional circuit-
ry is necessary.

That's all we have room for now. Next
time, we'll finish up our look at the detec-
tor circuit and show you how to build our
filter. R-E



50




Capacitor
Leakage Tester



GARY McCLELLAN



Find the leaky capacitors that many testers miss with this easy-to-build leakage checker. You
can use it to test cables, appliance insulation, and high-voltage diodes, too!



THOSli NEW DIGITAL CAPACITANCE TliST-

ers make capacitor checking quick and
easy, but they have shortcomings. For in-
stance, does the following sound familiar
to you?

You are troubleshooting a piece of
equipment and replace some defective ca-
pacitors with units from the junk box.
After hours of additional troubleshooting
you discover that those replacement ca-
pacitors are no good after all, even though
they checked out OK on your tester. That's
because they are leaky, and your meter is
one of the many that has no leakage-test
function. That "missing feature" wound
up costing you much time and aggrava-
tion.

Or perhaps you just bought some elec-
trolytic capacitors from your dealer, in-
stalled them, and watched as the power-
supply fuse blew. You later find that the
cause was those "new" capacitors; they
had become leaky after sitting on your
dealer's shelf for the better part of a de-
cade. If you had only known, those capac-
itors could have been rejuvinated with a
shot of current from the proper source.
Instead, you have a blown fuse and some
fried capacitors.



Assuming it does everything else well,
don't trash your capacitance tester just
because it doesn't have a leakage-test
function. Instead, supplement it with the
leakage tester described here. Our tester
checks the all-important leakage param-
eter quickly and easily, weeding out de-
fective capacitors that otherwise test
good, it can also brings those elderly
"new" capacitors back to life fast.

Besides checking capacitor leakage,
the circuit has many other uses on the
bench and in the field. For example, use it
to test insulation resistances on power
tools and appliances. If you find just one
tool or appliance with a dangerous fault
before it finds you. you'll be very glad you
took the time to build and use the circuit.
You can also test suspected lossy cables,
as well as high- voltage diodes, rectifiers,
neon lamps, and other high-voltage com-
ponents that are often difficult to trou-
bleshoot with conventional DMM's.

And in a pinch the circuit can serve as a
regulated power supply. The output volt-
age spans 3 to 100 volts, which may make
the project useful for temporarily power-
ing devices drawing under 10 mA or so.

The circuit is easy to build and is fairly



inexpensive, too. A small PC board holds
the active components, including two
IC's, three transistors, and some diodes,
while the remaining switches and a meter
mount on the cabinet. Parts costs will run
about $45.00 or so, depending upon how
well you can shop or scrounge for them.
The PC board, and a few harder- to-get
components, are available from the
source mentioned in the Parts List.

How it works

The project is basically a regulated DC
power supply with a metering circuit to
indicate leakage current. Refer to the-
block diagram in Fig. 1 for details.

There are several noteworthy features of
which you should be aware. First, a novel
power supply design permits the unit to
charge test capacitors with a constant cur-
rent source. That means they charge fast-
er, saving you testing lime, particularly
for large capacitors. In addition, an ana-
log meter is used for leakage -current mea-
surements. That allows you to see the
charging action and monitor the leakage
current easier than with a digital meter.
And analog meters are generally much
cheaper than digital ones!



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51



From McGraw-Hill . . . the professionals' publisher



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52



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E33801



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55



g

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o

LU

I

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■ m



PARTS LIST









\L TESTED
*T* CAPACITQfl



I

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S1-bi

°!S?tt*!!Si| check



Ml

LO-IQMA
METEH




FIG. 1— THIS BLOCK DIAGRAM makes it easier to see how our little leakage tester works.



In operation, 9 volts from a pi tig -in
transformer passes through switch Sl-a
and is rectified by diodes DI-D4. If field
operation is required, it is possible to sub-
stitute a 12-volt battery for the plug-in
transformer. The switch is a DPST unit
that selects either power on or capacitor
discharge. From the rectifier, the output
is filtered by capacitor CI, and is then
used to power the rest of the circuitry.

Part of the power output is fed to IC3, a
positive voltage regulator, which is used
to provide a stable 1.2 volt reference for
ICI. That ensures that the output voltage
will be stable regardless of how much
voltage is used to power the project.

Op-amp ICI serves as an error ampli-
fier. Its job is to ensure that the voltage
applied to the capacitor under test is regu-
lated. It does that by "sampling" the volt-
age at capacitor C5 through the range
switch. The range switch is nothing more
than a resistive attenuator network reduc-
ing the output voltage to about 1.2. The
op-amp simply adjusts the power supply
until its minus (inverting) input equals 1.2
volts. That regulates the output voltage.

Transistor Ql serves as a control ele-
ment for the rest of the power supply.
Since the op-amp can't provide enough
current to do the job directly, a Darlington
power- transistor is used here to boost the
current. Resistor R6 limits current to the
rest of the circuitry, preventing trans-
former damage.

Moving on, the DC output from capaci-
tor CI powers IC2, which is a CMOS
programmable one-shot wired as a 100-
Hz oscillator with complimentary out-
puts. The outputs from IC2 alternately
drive transistors Q2 and Q3 , which serve



as switches. They alternately switch each
side of the transformer Tl winding to
ground, generating current pulses.

Transformer Tl performs two pur-
poses. First it steps up the current pulses
so thai they can be rectified. Second, un-
der heavy load (as from a charging capaci-
tor) it saturates, limiting the output
current to the capacitor to about 20 mA.
That forms a constant-current type power
supply, which is especially effective in
charging test capacitors.

The output from transformer Tl is rec-
tified by diodes D7 to D10 and filtered by
capacitor C5. From that point the DC out-
put feeds back to the range switch, which
is used along with op-amp ICI to set the
output voltage. The DC output also drives
the test capacitor, which is connected to
the project through binding posts.

Meter Ml is included in the minus leg
of the test capacitor for monitoring the
charging and discharging currents. Note
that resistor R12 and switch Sl-b are in-
cluded to discharge the test capacitor
when the power is turned off.

That takes care of the basics. Now turn
to the schematic diagram of Fig. 2 for
some details on the finer points of the
circuitry. You should be able to identify
the parts we just discussed on the sche-
matic diagram.

First let's look at the error amplifier,
ICI. Basically, that amplifier is set up as
an inverting, gain-of-100 unit. Resistors
R3 and R5 set the gain value. Although
that practice is rather unusual for a power
supply (R5 is usually not included), the
reduced gain is necessary to permit stable
operation when testing very large capaci-
tors (say 15,000 u,F), Diode D5 serves as



A! I resistors Vi-watt, 5%, unless other-
wise noted
Ri— 8200 ohms

R2— 5000 ohms, potentiometer, PC
mount (Circuit Specialists 32JQ305 ot
equal)
R3— 100,000 ohms
R4— 270 ohms
R5— 10 megohms
R6— 10 ohms, 2 watts
R7— 2200 ohms
R8— 1 megohm
R9, R10— 10,000 ohms
R11— 18,200 ohms, Va-watt, 1%, metal-
film
R12— 100 ohms. 2 watts
R13— 10 ohms
R14 — 6B ohms

R15— 30,1 00 ohms, '/B-watt, 1%, metal film
R16— 40,200 ohms, H>-watt. 1%, metal

film
R1 7— 49,900 ohms, H-watt, 1%. metal

film
R18, R1 9— 100,000 ohms, W-watt, 1%,

metal film
R20— 150,000 ohms, Ms-watt, 1%, metal

film
R21, R22— 249.000 ohms, tt-watt, 1%,

metal film
Capacitors

CI— 1000 (j,F, 16 volts, axial leads, elec-
trolytic
C2, C6— 0.1 u.F, 50 volts, polyester
C3— 0.001 u.F, 50 volts, polyester
C4— 100 (xF, 16 volts, radial leads, elec-
trolytic
C5 — 2u.F, 450 volts, axial leads, elec-
trolytic
Semiconductors
ICI— LF356N op-amp (National)
IC2— 4047 CMOS one-shot (RCA)
IC3— LM317LE adjustable voltage reg-
ulator (National)
Q1-Q3— TIP120 NPN Darlington (Radio

Shack 276-2068 or equivalent)
D1-D4, D7-D12— 1N4004 rectifier di-
odes, 400 PIV, 1 amp
D5 — 1N4148 silicon signal diode
D6 — not used
Other components
M1— 1-mA DC meter
S1— DPST miniature toggle switch
S2— 12-position, 1-pole rotary switch (Ra-
dio Shack 275-1385 or equivalent)
S3 — SPST normally-closed pushbutton

switch
T1— 117 volts/12.6 volts, 1.2 amps, center

tapped (see text)
T2— 11 7- volts/9 volts, 300 mA, wall-plug

transformer
Miscellaneous: PC board, plastic case
(Radio Shack 270-627 or equivalent),
knob, hookup wire, 4-40 hardware, press-
on decats, etc.

An etched and drilled PC board plus all
1% resistors listed above and voltage
reference IC3 are available for $17.50
postpaid from: Mendakota Products,
PO Box 2296, 1001 W. Imperial Hwy? La
Habra, CA 90631. When ordering re-
quest part LCI and enclose a check or
money order for the appropriate
amount. California residents include
6% sales tax. Sorry no COD's or credit
card purchases.



56



117V AC



DISCHARGE




?SEE TEXT



FIG, 2— THE CIRCUIT of our leakage tester is seen in greater detail In this schematic diagram.




overload protection, preventing excessive
voltage from range switch S2 from
damaging IC1. That condition might oc-
cur if you were to switch rapidly from 100
volts to 3 volts. And finally, capacitor C2
provides some AC feedback, insuring sta-
ble operation over a wide range of capaci-
tor loads.

Moving on, let's look at IC2. Resistor
R8 and capacitor C3 set the operating
frequency to 100 Hz. That frequency,
while not critical, was chosen to prevent
"beats" with the 60 Hz power line and
permits increased output from trans-
former TL

And finally, let's look at the metering
circuit. Diodes DII and DI2 are included
to protect the meter from harmful over-
loads, especially when a large capacitor is
being discharged. A 10-mA current shunt
consisting of resistors R 13 and RI4 is also
included for measuring currents in non
capacitor- testing applications. That shunt
can be selected via pushbutton switch S3.

So much for the theory. Now why not
get started building your project?

Construction

We'll describe assembly shortly, but
first a few words about obtaining the parts.
The circuit uses no exotic parts, and most



should be available from Circuit Spe-
cialists (PO Box 3047, Scottsdale, AZ
85257), Radio-Shack, or your favorite
electronics parts supplier. If you order the
PC board from the supplier listed in the
Parts List, you will also get the harder-to-
rind 1% resistors and voltage regulator. If
you have trouble locating some items, try
the suppliers that advertise in the back
pages of this magazine. If after all of that
you are still having difficulty locating a
particular part, mail two first class stamps
and a self addressed, stamped envelope to
the PC-board supplier mentioned in the
Parts List for assistance.

A word about Tl: The board was de-
signed to accommodate a transformer that
was available from a parts supplier that
had nationwide outlets. Since then,
however, the transformer has been discon-
tinued by that supplier. Fortunately, any
1 2. 6- volt, 1.2-amp center-tapped trans-
former will do line, although it likely will
have to be mounted off the board.

Substitutions for other parts are also
acceptable, providing they are equal or
better in quality than the parts specified.

For the sake of both convenience and
safety, you should use a PC board. If desir-
ed, you can buy one form the supplier
listed in the Parts List, or else make one



from the artwork provided in the PC-ser-
vice section, found elsewhere in this mag-
azine.

Once you have assembled the parts and
obtained or made the PC board, you can
start construction. Refer to Fig. 3 for de-
tails as we discuss assembly.

Start by placing the board in front of
you with the foil side down. Then install a
100 u.F capacitor at C4 along the lop left-
hand corner.

Continue by installing a wire jumper
below C4. If you have been able to obtain
a transformer that will fit on the board (see
the preceding discussion), install it next.
Otherwise, that transformer will have to
be mounted off- the- board; in that event
the wiring between the transformer and
the board will be the among the last steps
in the construction process.

Next, install 1N4004 diodes at D7 to
D10 as shown. After that, install a 2-p,F
capacitor at C5, and a 100-ohm resistor at
R12.

Finish up the top half of the board by
installing a 18. 2K (usually marked 1822F)
resistor at R 11, then a 10-ohm unit at R13.
Also install a 68-ohm resistor at RI4 and
two 1N4004 diodes at Dl) and D12.

Move back to the left edge of the board
and continue assembly. Install TIP120



S
>
<

to

CD



57



BP1 BP2



Ml



Msu, svy^_




SEE
TEXT



R1S R16 R17 RIB R19 RZD R21 R22
FIG, 3— FOR SAFETY, this project requires a PC board. Here we see the parts-placement diagram for
the board shown in our PC Service section.



transistors at Q3 to Ql first. Note that the
leads are bent back 90 degrees, allowing
the transistors to be mounted with the
metal tabs flush against the board. Then
install I OK resistors at RIO and R9.

Continue by cutting a short length of
insulated wire and installing it between
Q2 and Ql . Position the wire so it doesn't
touch the transistors. Then install a 2.2K
resistor at R7 and a lO-ohni unit at R6.

Install a 14-pin IC socket at iC2. then
an 8-pin unit at IC1. Do not install those
IC's until laier. Next, install a O.QOl-u-F
capacitor at C3 and a I -megohm resistor
at R8, After that, install a 270-ohm re-
sistor at R4, a 0, !-u,F capacitor at C6, and
anLM317LEatIC3.

Finish the board by installing a 1N4148
diode at D5 and a 0. 1-p.F capacitor at C2.
Then install a 10-megohm resistor at R5
and a I00K unit at R3. Next install a 5K
potentiometer at R2. If the single-turn
unit specified in the parts list is used,
position the potentiometer with the ad-
justment screw next to the board edge.
Trie additional pads have been provided
around R2 so that a -Mi-inch, multi-turn
potentiometer (Radio-Shack 271-343 or
equivalent) can be used if desired. After
R2 is in place, install an 8.2K resistor at
Rl and the 1000-u,F capacitor at CI . Com-
co plete your work by installing IN4004 di-
^ odes at Dl to D4.

O Check your work carefully, especially
pE diode and capacitor polarities before con-
Jr] tinuing. fix any mistakes now, because
rjj they will be harder to correct later.
O Refer to Fig. 4 to see the construction
g details for S2 and its associated resistors,
cc Note that it is easier to wire the switch



now than later when it is installed on the
front panel. You might find assembly easi-
er if you clamp the switch's shaft in a vise
before starting work.



R18



RiT



R!9



R15



j*s\ n


c


>


tjt<X y° * *


' H


fl21/0<r ^-?




C^R22






REAR VIEW OF -
SWTCH St


i


r "



TO BOARD



; UNUSED POSITION






FIG. 4— RESISTORS R15-R22 are mounted on
the rear of S2 as shown. Be sure to tie any
unused switch positions to R15.

Wire the resistors on the back of switch
S2 as shown. Note that most l% resistors
arc marked in code: for instance, Rl5
would typically appear as "3012F."

When the resistors are wired in place,
use a piece of bare wire to connect any
unused terminals to R15 as shown. That
prevents dangerously high voltages from
appearing at the output terminals if S2 is
set to an unused position. Finish the
switch wiring by attaching 6-inch leads.

Set the board and switch aside for a
moment and prepare the chassis. Note



that the PC-board (and Tl if required)
mounts inside of the chassis, while every-
thing else goes on the front panel .

Place the board in the bottom of the
box, against the top side. Drill three
mounting holes for the board, plus a 1/4
inch hole in the top side for the power
cord. Drill another 1/4 inch hole in the
bottom side for access to pot R2. If Tl is
mounted of f-lhe-board , drill mounting
holes as appropriate for the unit you are
using.

Complete the mechanical work by in-
stalling the switches, binding posts, and
meter on the front panel. Connect the
switches to the appropriate points on the
board.

When done, check your work carefully
and correct any errors. Install the board in
the box using 4-40 X I -inch screws and
nuts. Use a nut as a spacer between the
board and box on each screw. If Tl is to be
mounted off-the-board, install it in the
chassis and wire the transformer to the
appropriate points on the board. Feed the
power cord (from T2) through the hole
that has been drilled for it and connect the
cord to the appropriate pads on the board.

Finish up the assembly by installing a
CD4047 at IC2 and an LF356 at IC1.

Checkout

Now we get to try the project out. Plug
transformer T2 into a nearby AC outlet.
Then set SI to the discharge position and
likewise set S2 to the I00-volt position.
Set your DMM to its 200-volt DC range
and connect it to the binding posts (BPI
and BP2).

Flip SI to the check position and the
DMM will read somewhere between 85
and 120 volts. If so, the project works and
you can go to the calibration.

If you are having problems, disconnect
the power and discharge capacitor C5
with a jumper wire. Then check over your
wiring for errors. Remember — when
troubleshooting, always discharge C5
after turning the power off; that can pre-
vent a dangerous shock.

Calibration

Calibration is easy to perform, first set
S) to discharge, and then set S2 to the
1 00- volt range. Then set your DMM to
its 200-volt DC range and connect it
across the binding posts. Flip SI to the
check position and adjust R2 until the
DMM reads 100 volts.

Tn be on the safe side, you should
check the output voltage for each position
of S2; it should be within 2% of the panel
value. If not, the 1% resistor associated
with that position should be checked.

Using the project

Danger, high voltage! This project can

provide a dangerous electrical shock if

misused. Avoid a harmful shock by using

continued on page 94



58



A Revolution in IC Packaging

We're in the midst of a revolution now — a packaging revolution!
Find out what it's all about, and get a glimpse of what lies ahead.



TJ BYERS



WHAT IS IT ABOUT ELECTRONICS THAT

fascinates so many people so deeply?
There are probably as many answers to
that question as there are people to answer
it, but no one could deny that pan of our
fascination is due to the rapid rate at
which innovations are thrust upon the
marketplace.

The problem is that today's innovations
soon become tomorrow's commonplaces.
Consumers quickly learn to take new
products for granted, so that what was
once superfluous soon becomes neces-
sary. And as users master the use of those
now-necessary products, their needs be-
come more sophisticated, In order to meet
those needs, electronic circuits must be-
come more complicated. Hence designers
find it increasingly difficult to fit the com-
ponents that are required into the space
that is allotted for those components. The
space problem is particularly acute in the
computer industry where standardized
card sizes and limited numbers of expan-
sion slots set artificial limits on expan-
dability.

In order to alleviate space problems de-
signers are constantly on the lookout for
ways of cramming more circuitry into the
same — or even less- — space. The first ma-
jor breakthrough occurred in the late
1940's when the transistor was invented.
The second breakthrough occurred in the
early 1960 's when the integrated circuit
was invented. We're in the midst of the
third stage right now; it comes in two
parts: VLSI (Very iLarge Scale /ntegra-
tion) and SMT (Surface Mount Tech-
nology).

VLSI refers to the design and manufac-
ture of IC's that contain great numbers of
transistors and other circuit elements.
SMT refers to extra-small components
(resistors, capacitors, transistors, IC's —
in fact, most components) that are sol-
dered to the surface of a PC board — but
with no legs penetrating to the opposite
side of the board! We won't discuss VLSI
any further in this article, but we will
discuss various SMT packages, how to
mount them to PC boards, and how to
troubleshoot and repair PC boards built
with SMT devices.



DIP vs. SMT

The success of the semiconductor in-
dustry is due, in great part, to the stan-
dardization of the DIP (Dual /nline
Package) IC. Basically, a DIP is a rec-
tangular block of plastic, ceramic, or
other material that encapsulates the sil-
icon chip on which the actual circuit ele-
ments are etched. Access to the chip is via
metal leads that protrude from both sides
of the case at intervals of 0. 100 inch. That
spacing arose from the need to have a lead
strong enough to withstand the rigors of
automatic insertion machinery.

The DIP has served the industry well,
but as the encapsulated circuitry has be-
come more complex, the package has
become larger. The problem is not
the size of the silicon chip; it's
that highly complex IC's
need more connections to
the outside world.



Since lead spacing is a fixed quantity, the
package grows larger while the chip itself
increases very little. We end up with a
very small chip in a very large container.

SMT to the rescue

IC's packaged in the SMT manner have
legs spaced on 50-mil (0.050-inch) cen-
ters, and that alone allows us to reduce the
size of an SMT package from 30 to 60
percent over a comparable DIP device.
This means that more IC's can fit in the
same amount of PC board space. In fact,
we might mount two or three IC's in the
space formerly occupied by one. Further,
using standard packaging techniques, sur-
face-mount assemblies can approach the
density of hybrid circuits, which are the
most densely-packed assemblies cur-
rently in production. And SMT assem-
blies can be repaired, whereas hybrids
cannot.

The advantages of SMT IC's become
apparent when they are used with double-
sided PC boards. Using surface-mounting
techniques, it is possible to have two com-
pletely different circuits on one PC
board — one on each side. That, of course,
is impossible with through-hole tech-
nology. The equivalent of two cards
can now occupy the space of
one, and signals can be




59



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passed from one circuit to the other using
jumpers from one side of the board to the
other, and that reduces outside wiring re-
quirements. And since the legs of an SMT
device don't penetrate the PC board,
boards are both cheaper to manufacture
and more reliable in operation.

Types of SMT devices

There are, basically, three different
types of surface-mounted IC's: the SOIC
(Small Outline /ntegrated Circuit), the
PLCC (Elastic leaded Chip Carrier), and
the LCCC (headless Ceramic Chip Car-
rier). See Fig. 1 to get an idea how each
looks in comparison with a standard DIP
package.

The SOIC is probably the most popular
SMT package; it was developed in Europe
in the mid 1970's for use in electronic
watches. The SOIC resembles a small
DIP with its leads bent out gull-wing style
and spaced at 50-mil intervals. The gull-
wing design permits the tips of the leads
to lay flat on the surface of the PC board: it
also allows easy access to those leads for
troubleshooting and repair. The SOIC
comes in 8-, 14-, 16-, 20-, 24-, and 28-pin
packages, and it can be handled by the
same automatic insertion equipment that
is used for DIP packages. That makes




LCCC LEAOLESS CERAMIC
CHIP CARRIER

FIG. 1— THE THREE MAIN TYPES OF SMT DE-
VICE are shown beneath a standard DIP device.
The drawing is not to scale.



SOIC the preferred choice when several
packaging technologies are used on the
same PC board.

The PLCC

The leads of a PLCC package are
formed in a way that is similar to the way
SOIC leads are formed. The difference is
that the leads are rolled up under the
molded plastic body in a ./-like shape.
Tucking the leads beneath the package
reduces the size of the IC; that allows
greater component density, and it also
provides protection from lead-handling
damage. But the tucked-in leads are hard-
er to get at. so PC boards are harder to
troubleshoot and repair.

The PLCC's biggest advantage over the
SOIC is that a PLCC can have leads on all
four sides. To understand how important
that can be, consider this: The DIP pack-
age grows disproportionately larger than
the chip it houses because of the addi-
tional width required to route intercon-
necting wires from the silicon die to the
outside world. The more leads a DIP con-
tains, the wider it must be to avoid the
possibility of two leads shorting together.
Four-sided carriers help alleviate that
problem by connecting leads to the pre-
viously unused ends of the package.
PLCC's have another advantage in that
they can be socketed, but SOlC's cannot.

PLCC's are available in IS-, 20-, 28-,
44-, 52-, 68-, and 84-pin packages;
they're footprint-compatible with
LCCC's, discussed below; and they con-
form to J ED EC (Joint Electronic Devices
Engineering Council) standards. PLCC's
currently cost about the same as standard
plastic DIP's.

LCCC's

The third major type of SMT IC burst
upon the scene in the early I970's. The
most notable feature of the LCCC is that it
has no leads; rather, metallic contacts are
molded into its ceramic body. Like the
PLCC. the LCCC can have from 20 to 84
contacts on all four sides. LCCC's are the
most rugged members of the SMT family,
and that explains their preference by the
military. An LCCC device mounted on a
PC board is shown in Fig. 2, and an LCCC
with its "hat" off is shown in Fig. 3.

There is one problem with LCCC's. An
LCCC must be bonded to its circuit board
rigidly. Although that is desirable me-
chanically, it creates thermal problems.
All things in nature — circuit boards and
IC's are no exception — change in size as
temperature changes, and different mate-
rials have different coefficients of expan-
sion. That is, some things expand more
than others for the same change in tem-
perature. For example, the ceramic of an
LCCC and the glass cpoxy of typical PC
boards have different coefficients of ex-
pansion. The shearing force that develops
because of those different amounts of ex-



IBlpjPi








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FIG. 2— NEW IC'S OFTEN COME IN SMT FORM,
but the bulk of many circuit boards will continue
to be DIP IC's.



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FIG. 3— THE GUTS OF AN LCCC DEVICE reveal
the closely-spaced wires that connect the chip
to the outside world.

pansion can cause solder bonds to snap. In
comparison, SOIC and PLCC packages
aren't affected by thermal expansion be-
cause the stress is absorbed by their re-
silient metal legs.

The problem of thermal expansion has
plagued the LCCC since its introduction,
and it's the major reason why the LCCC
has had so little impact on the commercial
market. Only by using expensive, ther-
mally-compensated PC boards, made
with such exotic materials as Invar, are
LCCC's really practical.

To avoid thermal expansion problems,
an LCCC can be mounted in a socket.
Sockets, however, have problems of their
own, and actually defeat some of the ad-
vantages gained by the LCCC package.

Now that we've got an idea of the dif-
ferent kinds of SMT IC packages that are
available, let's take a look at how we can
use them.

Using SMT IC's

Since SMT devices are soldered di-
rectly to PC boards with no additional
mechanical support, special handling is
required. First, you must realize that the
only mechanical bond between the device
and the board is the solder connection
itself. Consequently, the solder joints
must be not only electrically sound, but
mechanically strong.

Unfortunately, only the SOIC, with its



60



gull- wing design, lends itself well to con-
ventional soldering methods. Both the
PLCC and the LCCC packages have their
solder contacts tucked under the body of
the device where they are relatively inac-
cessible.

Manufacturers have overcome that
obstacle by using techniques like reflow
soldering. In that process both the pads on
the PC board and the leads of the SMT
device are pre-tinned. Next, a flux is ap-
plied to the solder pads on the PC board;
that flux contains a quantity of granulated
solder (85-90% by weight) that is held in
suspension by the thick flux paste.

The 1C is aligned with the solder pads
and pressed into place. The entire assem-
bly — -PC board, components, and all — is
then heated to a temperature where the
solder melts and the flux evaporates. At
that temperature, the solder on the leads
of the device, the solder on the PC pads,
and the solder in the paste flow together
and become one. Cooling the assembly
solidifies the molten solder, and that
forms a connection that is (hopefully)
electrically and mechanically sound.

Several methods of heating are cur-
rently in use, including infra-red, vapor
phase, and convection. With minor ad-
justments, conventional wave- solder ma-
chines can also be used for SMT
components, but those components must
be glued to the PC board prior to immer-
sion.

Part alignment, of course, is critical to
the success of reflow soldering. With no
leads projecting through holes in the PC
board to secure them in place, leads and
solder pads can become misaligned.
Manufacturers try to counter that problem
by adding an adhesive compound to the
flux so that the part is held tightly in place
until the reflow process heats the flux to
the point of evaporation. Most types of
flux adhesive are hardened using ultra-
violet light, but some permit air drying.

Of the three major types of SMT pack-
ages, the LCCC is the most forgiving of
misalignment. In fact, as much as 25%
misalignment is permitted because the
surface tension of the molten solder al-
lows the LCCC to align itself with the PC
board's solder pads. SOIC and PLCC de-
vices are not so forgiving. Unless the er-
ror is very small, any misalignment in
parts of those types could be disastrous.
How can we correct such errors?

SMT troubleshooting

It is estimated that, by 1990. 70 percent
of all electronic equipment throughout the
world will be manufactured with SMT
devices. Consequently, the hobbyist as
well as the service technician will soon be
faced with a whole new set of fabrication
and repair problems.

Size is one such problem. SMT pins arc
spaced 50 mils apart, so troubleshooting
with standard test probes will be like knit-



ting with telephone poles! The narrow
width of an SMT lead makes it difficult to
get a probe into the test area, and it makes
it easy for the probe to slip and to short
adjacent pins. The result of such a slip
could be devastating to the circuit.

The actual mounting technique itself is
the source of another problem. Often,
much of the interconnecting circuitry —
the etched copper traces — lies buried be-
neath the SMT components. That makes
it hard to perform standard signal tracing.
The problem is compounded further by
high component density, which leaves few
traces between components exposed.

One way of getting at LCCC leads is
with an 1C test clip, like the one shown in
Fig. 4. Since the contacts in the clip are
precisely spaced and rigidly fixed, the
danger of shorting pins together is re-
duced. Unfortunately, you need a dif-
ferent test clip for each package size. One
thing that could help the IC test-clip
crunch is to place strategic test points on
the PC board in easily-accessible places.




FIG. 4— QUAD CUP FROM POMONA attaches to
a 68-pin PLCC and allows the user easy access
to the closely-spaced leads of the device.

Test equipment will also be affected by
increased use of SMT devices. For exam-
ple, we'll need equipment with faster
clock speeds and faster rise times. The
reason is that, by reducing the size of
components, and thereby shortening the
signal paths between them, rise and fall
times become sharper, and clock rates can
increase. You'll find that test equipment
that worked well with DIP devices can't
monitor the faster events of SMT units.

SMT repair procedures

Tracking down a bad SMT device will
be difficult, but it will be even more diffi-
cult to remove that device and mount a
new one in its place. One useful tool for
SMT removal, the heated collet, is shown
in this story's opening photo.

A heated collet is quite similar to a
desoldering tool used to remove DIP de-
vices. A DIP-desolderer is a bar of metal
that makes contact with, and thereby
heats, all pins of a device at the same
time. After the solder melts, the part can
be removed from the board easily.

SMT soldering collets work somewhat
differently than DIP desoldering tools.



First, the collet clamps around the device
itself, rather than contacting the through-
hole pads of the PC board. So a separate
collet is required for each package size. In
addition, the collet must heat the entire
SMT device, along with the pads on the
board, so precise heat regulation is re-
quired in order to avoid destroying a heat-
sensitive part. And that, of course, results
in an expensive tool.

A heated collet can also be used to
attach a replacement device. However, the
PC board and the SMT devcice must be
prepared for reflow soldering.

Begin by removing excess solder from
the pads on the PC board. Braided solder
wick works well for that chore. After the
pad is completely clean, apply a dab of
reflow soldering flux to each pad. Only
reflow flux (which contains solder) can be
used; conventional flux compounds will
not work. The amount of flux that is re-
quired varies from brand to brand, so you
should read the directions that come with
the product. Most surface-mounted de-
vices are pre-tinned, but you should make
sure that your device is properly tinned
before trying to mount it. If necessary, tin
the leads of the new component. In any
case, tarnished leads should be thor-
oughly cleaned and freshly tinned.

Now align the part with the solder pads,
taking careful notice of pin orientation.
Although at room temperature many re-
flow fluxes are sticky enough to prevent an
SMT device from moving, as the flux is
heated, the device may begin to creep.
Therefore, you should glue the part in
place with a quick-setting adhesive (from
a hot-glue gun, for example) to keep
things aligned. You must be extremely
careful to align the leads with the solder
pads perfectly before the glue sets — other-
wise you may have a real problem!

After the glue has set, apply the heating
collet to the replacement IC. Within a few
seconds the flux should vaporize and pro-
duce a small puff of smoke. Keep the
collet pressed against the IC for a second
or two longer and then release it. This
ensures that the solder from all three
sources will flow together smoothly.
Don't heat an SMT device for more than
about 10 seconds or the device may be
damaged. You can remove excess flux
from the board with denatured alcohol .

Removing an SOIC device is easier be-
cause the gull-wing leg design allows the
legs to be accessed individually with a
low-powered soldering iron. The problem
is that, even though SOIC devices are easy
to replace, the industry tends to use PLCC
devices more often because they have a
smaller footprint, and because they are
easier for automatic insertion equipment
to handle.

As we mentioned above, IC's aren't the ^
only devices that come in SMT packages. ■<
Let's take a look now at how several other S
devices are packaged . an



61



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One-megabit DRAM

The semiconductor industry is on the
verge of perfecting a i-megabit Dynamic
Random Ac cess Memory iC, so manufac-
turers are designing an appropriate pack-
age. To arrive at a standard, manufac-
turers are looking beyond just package
design. Trends indicate that sales of both
256K DRAM's and one-megabit
DRAM's could be the largest the semi-
conductor industry has ever seen. So the
configuration arrived at now will affect
Future DRAM designs considerably.

The problem is simply that the standard
DRAM package, which has satisfied
memory needs for ten years now. has run
out of space. When that package was cre-
ated, it had more pins than were needed.
But as memory chips grew in size, more
and more of those pins were used, and the
256K DRAM has claimed the last pin.

In addition to running out of pins, de-
signers also want to take advantage of the
benefits provided by SMT packaging.
One design that is receiving critical re-
view is the Small Outline ./-lead, or SOJ.
surface-mounted package that Texas In-
struments has proposed: it is shown in
Fig. 5.




FIG. 5— TI'S PROPOSED ONE-MEGABIT DRAM
allows an SMT bypass capacitor to be mounted
beneath the IC.

Calling on its years of surface-mount
experience, Tl has introduced an iC car-
rier that is a radical departure from main-
stream PLCC designs. TI's SOJ device is
a 26-pin package in a 300 x 675 mil
(width x length) configuration. Since the
IC uses only 20 pins, TI reasoned, six pins
could be removed — from the middle of
the carrier. TI thought thai, by removing
the pins from the center of the carrier,
there would be space to mount a decoup-
ling capacitor beneath the IC, as well as to
provide room for routing PC traces.

The concept quickly gained wide ap-
proval, and the outline has been accepted
by JEDEC (Joint Electronic Devices En-
gineering Council) as the standard config-
uration for one-megabit DRAM's. The
only factor that remains to be decided is
the final size of the SOJ device.

Surface-mounted transistors

Two standard packages, the TO-236/
SOT-23 and the TO-243/SOT-89, already



exist for surface-mounted transistors and
diodes. The TO-xxx is the designation
used in North America, and the SOT-xx is
used in Europe. The designations mean
the same thing, but SOT is the popularly-
accepted nomenclature both in the U.S.
and abroad. TO is the acronym for tran-
sistor Out line, and SOT for Small-Out line
Transistor.

Originally designed for use in hybrid-
circuit construction. SOT packages are
normally used to house small-signal tran-
sistors: the package can dissipate up to
200 mW in free air. The performance of
SOT devices is equal to that of con-
ventionally-packaged ones.

As shown in Fig. 6. the SOT-23 pack-
age has three leads, two on one side, and



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FIG. 6— THE SOT-23 TRANSISTOR package Is
only about 0.25-inch on a side.

the third in the center of the opposite side.
The leads are formed in gull-wing fashion
similar to the SOIC. The SOT-23, includ-
ing leads, is about '/io-inch on a side —
that's about 1/3 the size of an ant!

Other SMT devices

New SMT configurations are intro-
duced often. For example, the SOS pack-
age shown in Fig. 7 is actually about 0.25-
inch on a side, but it is functionally equiv-




a



W- ^



FIG. 7— THE SOS IC PACKAGE Is also about
0.25-Inch on a side and It contains the equiv-
alent of a 78LD5 regulator.

alent to a 78L05 voltage regulator. In ad-
dition, components other than semicon-
ductors are becoming available in SMT
configurations. For example, the devices

shown in Fig. 8 are surface-mount trim-
mer resistors manufactured by Noble




FIG. 8— TRIMMER RESISTORS also come in
SMT form; each device is about 4 mm on a side.

U.S.A. (151 Stanley Street, Elk Grove
Village, IL 60007). The "chip trimmer"
devices can operate at temperatures rang-
ing from - 30°C to + 100°C, and they can
handle 200 mW of power at 20 volts. They
measure about 4 mm on a side, and
they're about 2 mm thick.

SMT in the real world

To get an idea of how SMT devices may
be used, take a look at Fig. 9. Shown there
isa!2SK x eight-bit static RAM module:




FIG. 9— STATIC RAM MODULE built with SMT
devices uses less power than comparable dy-
namic RAM's.

overall dimensions of the device are less
than 1" x 5". There are eight 8K X S-bit
static RAM's and a custom decoder IC
mounted on one side of the module, and
eight more RAM's and four 10 u,F bypass
capacitors mounted on the other side.

According to the manufacturer (Ad-
vanced Electronic Packaging, 2159 Bay
Street, Los Angeles, CA 90021). the mod-
ule uses 500 times less power bit-for-bit
than a conventional 256K x one-bit dy-
namic RAM.

Conclusions

The watchword in electronics these
days is SMT, and what SMT stands for is
increased utility that uses less power and
that occupies less space. For example,
one company is marketing 20-megabyte
disk drives for the IBM PC. The complete
disk controller electronics, as well as the
drive itself, is mounted on a single stan-
dard-sized plug-in expansion card.

The increased utility that SMT brings,
however, goes hand-in-hand with new
problems in manufacturing and trou-
bleshooting. So new tools and techniques
will be needed to keep up with SMT. R-E



62



TPfflM^T



Making Measurements with IC's

New IC sensors are revolutionizing the way industry gathers information. In this article we learn
about the kinds of devices currently available, and what shape future sensors are likely to take.



HARRY L. TRIETLEY

WE ALL KNOW HOW SEMICONDUCTOR

technology lias revolutionized elec-
tronics. In one generation we have gone
from hand-wired assemblies using vac-
uum tubes to entire computers mass-pro-
duced on silicon wafers by largely-
automated processes. That revolution has
transformed industries, and, indeed, the
economy of the world. Needless to say,
the effects have also been felt in the fields
of consumer and hobby electronics.

The electronics industry is now in the
early stages of a similar revolution in sen-
sor manufacture. At present, most devices
that measure such variables as tem-
perature, pressure, force, and chemical
composition are assembled from discrete
components, and often require machin-
ing, hand assembly, soldering, welding,
gluing, epoxying, etc. Now, however,
new techniques for the creation of me-
chanical microstructures and chemically-
sensitive devices in silicon are changing
all that. Integrated silicon devices measur-
ing temperature, strain, pressure, and vid-
eo images already are available from
several manufacturers. University and
laboratory research is progressing on
electrochemical and other complex sens-
ing devices. In this article we'll take a
look at today's sensor products, the re-
search that is being done in the field, and
what form future sensors might take.

Temperature sensors

The drop across a forward -biased P-N
junction (diode or base-emitter junction)
is about 0.7 volts ai 25°C. As temperature
rises, that voltage drop decreases by about
-2millivoIts/°C. Because of that, diodes
and transistors are sometimes used as
temperature sensors, especially in com-
pensation applications where absolute ac-
curacy is not important. The exact
temperature sensitivity depends on the
semiconductor's doping, the junction's
geometry and current density, and resis-
tances in series with the junction. Those
characteristics vary from device to device.
Manufacturers do not normally control or
test for exact temperature coefficient.

Temperature sensor IC's having con-
trolled characteristics are available: they
are generally housed in conventional tran-
sistor or IC packages. Several different
families exist, each with its own unique
circuitry and output. Fig. 1 shows the



schematic of one device, an Analog De-
vices AD590. In that IC, two identical
transistors, Q9 and Ql I , are connected so
that the ratio between their two collector
currents is fixed. For a ratio r, the dif-
ference between their base-emitter volt-
ages will be proportional to absolute
temperature, T. More specifically, the dif-
ference will be (kT/q)(ln r), where k is
Boltzman's constant, q is the electron
charge and (In r) is the natural logarithm
of the current ratio.

That voltage is converted to a current by
R5 and R6, which are low-temperature-
coefficient thin-film resistors that are



laser-trimmed for proper calibration at
25°C. The collector current of Q10 tracks
those of Q9 and Ql 1 . Transistor Ql 1 sup-
plies all the leakage and substrate current
used by the rest of the circuit. That forces
the entire current to be proportional to the
absolute temperature. The AD590 is a
two-terminal device, inserted in series
with any DC supply between 4 and 30
volts, regulating the series current to be
equal to lp,A/ D K, where °K is the Kelvin
temperature (1°K equals 1°C plus 273. 15.)
The operating range for temperature-
sensor IC's is similar to that of other IC's,
generally - 55 to + 150°C. Although lin-




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FIG. 1— IN THIS IC TEMPER ATURE SENSOR, the
ADS90, the ratio of the base-emttter voltages of
Q9 arid 011 Is proportional to the absolute tem-
perature.

ear, their accuracies and stabilities do not
yet equal those of other temperature sen-
sors. Remember, however, that those de-
vices have only recently been developed
and their performance is likely to improve
with continuing research.

Strain gages

Strain gages respond to mechanical
stress, changing their resistances as they
are stretched or compressed. Bonded to
metal or other slightly elastic surfaces,
they are often used to measure mechanical
force, weight, or tension. Lengths of
doped silicon (that is, silicon resistors)
undergo noticeable resistance changes
when they are stressed, mainly because
distortion of their crystal lattice structure
changes both the concentration and the
mobility of their charge carriers (electrons
or holes).

Strain gages increase (p-rype) or de-
crease (n-type) in resistance as they are
stretched. Strain gages may typically be
stretched or compressed up to 0.5% of
their original length, at which point they
will undergo resistance changes of be-
tween 25% and 100% depending on their
doping.

A multiple strain gage, perhaps config-
ured as a strain-gage bridge as shown in
Fig. 2-fl, may be diffused into silicon
structures. Two such structures are shown
in Fig. 2; Fig. 2-a shows a diaphragm
while Fig. 2-b shows a beam. The di-
aphragm is used to measure pressure, as
we shall see shortly, while the beam is
used to measure force.

Unfortunately, silicon resistors are af-
fected by temperature as well as strain. (In
fact, they are also sold as positive-tem-
perature-coefficient thermistors.) With-
out some sort of compensation, normal



ambient temperature fluctuations can
cause significant measurement errors.
Also, even at a constant temperature, their
sensitivity and calibration will vary from
unit to unit. Those effects can be compen-
sated for by using fixed resistors and con-
necting the gage or gages as a Wheatstone
bridge. The value of those fixed resistors
is determined by measuring the bridge's
behavior at two or more temperatures.
That information is then fed to a comput-
erized circuit model to calculate the fixed
bridge-resistor values. The resulting cir-
cuit generally looks somewhat like the
one shown in Fig. 3, Those measurements
and calculations are beyond the ca-
pabilities of most experimenters and
many production facilities; however, man-
ufacturers of the devices (especially inte-
grated devices such as those in Fig. 2) can
supply the calculated values for each indi-
vidual device.

Pressure sensors

Integrated-circuit pressure sensors are
made by etching a thin membrane in sil-




^=litx








icon. A strain-gage bridge is diffused into
the membrane and protected by a grown
layer of silicon oxide as shown in Fig. 4.
The cavity behind the diaphragm is cov-
ered by a Pyrex or silicon backing-plate.
Barometers or absolute pressure sensors
are created by evacuating and sealing the
cavity, while gage-pressure or differen-
tial-pressure devices include an opening
through the back plate.

Integrated pressure sensors are most
often mounted in transistor-type hous-
ings. Absolute pressure sensors have a
single hole or connection tube; gage- or
differential-pressure devices include a
second opening. Manufacturers offer as-
semblies designed for more rugged ap-
plications, including industrial assem-
blies in which the IC is protected from
corrosive fluids by stainless-steel di-
aphragms.




FIG. 2— A STRAIN GAGE BRIDGE (a) can be
defused into a silicon diaphragm to measure
pressure (b) or Into a beam to measure force (c).



FIG. 3— FIXED RESISTORS can be added to a
silicon strain-gage bridge to adjust Its sen-
sitivity and minimize its drift with temperature.

Let's look at some typical transducer
specifications. Pressure ranges run from 5
to 5,000 psi, with full-scale sensitivities
between 50 and 300 mV. Sensitivity toler-
ances may be ±25 or 50% of nominal,
with zero-offset tolerances adding an-
other several percent. It is up to the user to
calibrate his readout circuitry to match
each particular sensor. With some devices
it is also necessary to add temperature-
compensating resistors using values com-
puted by the manufacturer as mentioned
earlier. Some manufacturers do supply
calibrated assemblies including elec-
tronics; those, however, are not mono-
lithic ICs.

Acceleration

To simplify things somewhat, accelera-
tion may be measured by attaching a mass
to a spring or other elastic device. When
the opposite end of the spring is acceler-
ated, the spring stretches or is com-
pressed. The change in length (strain) is
proportional to the rate of acceleration.

The basic concept, as applied to an in-
tegrated semiconductor-accelerometer, is
shown in Fig. 5. A thin cantilever beam is
etched into the silicon crystal, using an
anisotropic etchant, which dissolves the
silicon well in certain direction but poorly
in others, to etch a cavity under the beam.



64



A mass is attached to the unsupported end
of the cantilever, either by etching so as to
leave a mass of silicon or by adding a
heavy electroplated layer of gold. The de-
vice is sealed with a protective glass top
cover. Typical dimensions of an experi-
mental device reported by Stanford Uni-
versity are 2- x 3- x 0.6-mm. The
cantilever itself is 15p,m thick.

When the device is accelerated perpen-
dicularly to the cantilever, the beam Hex-
es, its displacement being proportional to
the acceleration. Displacement may be
measured by diffusing a strain gage into
the cantilever or by depositing a
piezoelectric material on it.

Note that the device discussed here is
experimental; as far as the author is aware,
no commercial 1C accelerometer devices
are available at this time.

Ha 1 1 -effect sensors

A Hall-effect device (the Hall effect
was first demonstrated by E. F. Hall in
1879) measures magnetic -field strength by
deflecting moving electrical charges in a
semiconductor. The amount of deflection
of that moving charge is proportional to
the field's strength.

The concept behind the Hall-effect de-
vice is shown in Fig. 6. Electrons flowing
in an n-type semiconductor are deflected
by the magnetic field at right angles to the
direction of the current. That causes them
to drift to the right, inducing an electric
field between the sides of the semiconduc-
tor as shown. The electric field's force
opposes the magnetic deflection, produc-
ing a balanced condition. As a result, the
induced voltage is proportional to both the
current and the strength of the magnetic
field. A similar effect occurs in p-type
semiconductors; however, the induced
electric field's polarity is opposite that
shown in Fig. 6.

Several companies, including Sprague
and Texas Instruments, offer commercial
devices based on the Hall effect, usually
integrating analog or digital signal-con-
ditioning circuitry with the sensor.

Digital-output devices are used in con-
junction with permanent magnets as prox-
imity switches and mechanical limit-
sensors, and may replace mechanical rni-
croswitches in many applications. They
are useful in keyboards (the magnet is in
the switch cap) and other control devices,
having no contacts to wear or bounce.
Other applications are as diverse as pin-
ball detectors and ignition switches.

Analog-output Hall-effect devices are
used to measure magnetic flux or to sense
movement of a permanent magnet. The
latter, of course, allows movement to be
translated into an electrical signal. A Hall
device also can serve as the secondary of a
DC transformer to allow the isolated mea-
surement of DC currents. Let's explain
further: A winding on a transformer core
produces a field proportional to its cur-





ETCHEQ SILICON
DIAPHRAGM



VENT OPENING
(GAGE PRESSURE
ONLY)



FIG. +— AN INTEGRATED PRESSURE SENSOR is created in silicon by etching a thin membrane, then
diffusing four strain gages in It. The sensor Is completed by sealing It with a backing of Pyrex or
silicon.



MONOLYTMC
SILICON BLOCK




FIG. 5— A COMPLETE ACCELEROMETER can
be etched from a single, monolithic crystal of
silicon. A strain gage diffused Into the cantilever
beam detects the flexing of the beam as the
device is accelerated or vibrated.

rent; the Hall effect sensor is used to mea-
sure the field directly, and the DC current
indirectly. In the case of large currents
{say, 30 amps or more) the primary can be
a single wire inserted through the center of
the core.

Image detectors

TV and image detectors are large-scale
photodiode arrays, integrated with
switching and shift register circuitry that
scans the diodes and produces a serial
output. Array sizes run from single-line
devices of 64 to 4,096 diodes, to matrix
arrays of up to 256 x 256 (65,536 di-
odes). Applications include optical
character-recognition, single-line arrays
used in the wands that scan prices and
inventory codes at checkout registers,
robotics, and other industrial applica-
tions, and TV. Arrays are available that
detect infrared. X-rays, and visible light.

Photodiode arrays are usually housed
in 1C packages with ground and polished
glass windows. Two single-line arrays,
and their associated circuitry, are shown
in Fig. 7. In Fig. 7-a, the diode charges
are transferred to a charge-coupled device
(CCD) analog shift-register (a bucket-bri-
gade device) and then clocked sequen-
tially to the output. The circuit of Fig. 1-b
clocks a pulse through a digital shift-regi-




FIG. 6— IN HALL-EFFECT SENSORS, the pres-
ence of a magnetic field deflects moving elec-
trical charges, Inducing an electrical field and
hence a voltage.

ster to connect one diode at a time to the
output line. Matrix arrays, of course, use
two-dimensional switching arrays.

Tile sensing elements are diffused-
junction pn diodes, which convert light to
an electric charge. The charge builds up
(integrates) as long as the diode sees any
light; the total charge is dumped when
each diode is connected to the CCD or
output line. The longer the time between
frames the more charge builds up. Thus,
there is a tradeoff between speed and sen-
sitivity. Clock frequencies of I to 5 MHz
are common, and devices with speeds of
10 MHz are available.

Gas chromatograph

Probably the most complex IC sensing
device to be designed to date is a gas
chromatograph. The gas chromatograph
is a device that is used to separate and
identify the contents of a sample of a gas-
eous mixture. S

In a gas chromatograph, the sample to <
be analyzed is injected at the head of a ?
long, thin capillary column. It is then §



65



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flushed through the column by an inert
carrier gas. As it travels, the sample con-
stituents are absorbed onto the surface of
the capillary, which is usually coated with
a material that aids in that process. Once
the sample passes, however, the carrier
gas flushes the absorbed materials from
the capillary, carrying them out the end of
the column. Because different substances
are absorbed and released by the capillary
tube at different rates, that action sepa-
rates the gas sample into its component
parts. The output of the tube is monitored
to determine the time it takes for each
component of the sample to pass through
the tube. That information can be ana-
lyzed and used to identify the contents of
the gas.

Several different techniques are used to
monitor the tube's output; the method of
monitoring is a matter of choice, and
largely depends on the application. One
common monitoring method detects
changes in thermal conductivity (cooling
rate) as the composition of the gas stream
changes. By measuring the change in
cooling rate at the time each substance
emerges from the capillary, it is possible
to analyze both the types and the amounts
of the constituents of the gas.

An experimental integrated chro-
matograph developed at Stanford Univer-
sity is shown in Fig. 8. Most notable is the
capillary, a 1.5-meter long column etched
in silicon. Two long spiral grooves are
etched side-by-side and joined at the cen-
ter, creating a capillary that winds into the
center and then back out again. The cap-
illary is lined with an absorptive material
such as silicon oil and bonded under a





DETECTOR
CHIP



FIG. 8— AN EXPERIMENTAL GAS CHROMATOGRAPH IC Integrates a 1.5-meter long capillary column.
Input and exhaust ports, valve seats, and a thermal gas detector on a single 5-centimeter diameter
silicon wafer.



FIG. 7— THE OUTPUTS of an integrated pho-
todiode array can be clocked into an analog
CCD shift- register and shifted out (a), or scan-
ned sequentially using analog switches and a
digital shift register(b).



plate of glass. The entire device is built on
a single silicon wafer that is 5 centimeters
in diameter.

The device is not completely mono-
lithic. The necessary valve seats, inlets,
and outlets are etched in the silicon, but
the valves themselves are implemented
using miniature solenoids, plungers, and
diaphragms. The thermal detector is a
small thin-film resistor supported on a
thermally-isolated Pyrex glass mem-
brane.

Although the Stanford device is not
commercially available, Microsensor
Technology Inc. (Fremont, CA) has de-
veloped a similar silicon mechanism.
Their device does not incorporate the cap-
illary column, but it contains most of the
Stanford chromatograph's other features.
It is not available as a component, but is
built into a gas analyzer sold by Microsen-
sor Technology.

Future possibilities

Integrated transducers are in their in-
fancy. Potential advantages include size,
reliability, and mechanical ruggedness,
but perhaps most important is cost. The
cost of measurement electronics has been
dropping steadily due to advances in mi-
croelectronics and microprocessors, but
transducer costs have not kept pace. Re-
searchers are working to develop inte-
grated sensors capable of high- volume
automated production. Leading research
institutions include Stanford University,
Case Western Reserve, the University of
Pennsylvania's Moore School of Engi-
neering, Delft University of Technology
in the Netherlands, and several Japanese



research laboratories.

IC temperature-sensors presently have
much looser accuracy specifications than
resistance thermometers, precision ther-
mistors, or thermocouples. (Selected pre-
cision devices are available, but they are
very expensive.) It is reasonable to expect
better precision at lower prices in the fu-
ture.

Experimental pressure and accelera-
tion transducers have been built using
variable capacitance to detect motion.
The basic diaphragm and cantilever beam
designs of those devices are like those
described earlier, but the strain gages are
eliminated and replaced with metallized
surfaces that form the plates of variable
capacitors.

Because both the plates and their move-
ments are very small, the capacitance
changes generated within such a trans-
ducer are small compared to the shunt
capacitances of even the shortest external
connections. Successful commercial ca-
pacitance-type sensors will require mea-
surement circuitry to be integrated on the
same chip, something no manufacturer
has yet introduced.

It should be expected that, as reliable
sensors are developed, active circuitry
will be integrated with them. That not
only will provide signal conditioning and
amplification, but also will allow sensor
shortcomings such as nonlinearity and
calibration errors to be compensated for
by burning the appropriate data into an
on- board PROM, making user calibration
a thing of the past. Once it becomes prac-
tical to integrate sensors with their pro-
cessing circuitry, the possibilities will be
endless. R-E



66




Teletext Dec

Build this World System Teletext
decoder and tune in to a whole
new world of information.



J. DANIEL GIFFORD



Part 2



LAST MONTH, WE DE-

scribed what teletext is
and how it's broadcast and received. We
also described most of the decoder circuit
that we're building. But before we get to
construction details, we still have a couple
of circuit sections to look at: the RGB-to-
NTSC encoder and the video switch.

The RGB -to-composite- video decoder
is shown in Fig. 10. Although the R, G, B,
Y, and blanking outputs of the SAA5050
TROM (of the Mullard teietext module)
could be connected directly to an RGB
monitor for display, that's not particularly
practical because it makes TV/teletext
switching impossible. Therefore, the out-
puts of the module are routed to IC4, a
Motorola MCI 377 RGB-NTSC encoder
IC, That 1C combines the module's out-
puts into a standard NTSC composite-
color video signal. The RGB-NTSC en-
coder is the most complex portion of the
circuitry outside the module, but IC4
makes it a good deal simpler than it might
otherwise be.

To allow remote switching between
TV, teletext, and text-over-TV (mix)
modes, the original video signal from the
video buffer is sent to a video switch
along with the output from the MC1377.
That video switch is built around IC5, a
4066 quad analog switch, as shown in
Fig. 11. The switch is controlled by the Y



and blanking outputs from the TROM,
and by the module's picture on (pon)
signal, which is high when the TV picture
is to be displayed and low when teletext
only is to be displayed . Two of the gates in
1C3, a 74HCOO quad nand gate IC, are
used to invert the blanking and pon
signals; only the inverted blanking signal
(IE) is used, but both pon and pon are
used to obtain alternate switching.

The third nand gate in IC3 is used as
the active element in the MC1377's os-
cillator, and the fourth is not used.

The output of the video switch is sent to
the video output buffer, the output of
which is available at the video out jack,
J3. That signal, along with the output of
the audio buffer, is used to drive the Astec
UM 1285-8 video RF modulator. Switch
S2 is used to set the modulator's output on
Channel 3 or 4.

The power and channel -select switches
are the only controls on the decoder itself.
All other functions are controlled by the
remote handset. That makes this teletext
decoder easy to build.

Building the decoder

Building the decoder is reasonably easy
because the decoder itself is a pre-
assembled module. The Mullard
VM6780-2 teletext decoder module, as
discussed last month, performs almost all



A complete parts list appeared in Parti
of this article (April, 1986).

A kit of parts (No. K-6315), Including PC
board, case, and all parts— except
those for the wireless remote control
circuit, (a wired remote control unit is
substituted)— is available for SI 99.00
plus $10.00 shipping from Dick Smith
Electronics, Inc., P.O. Box 6021, Red-
wood City, CA 94063; 300-332-5373 (or-
ders) 415-368-8844 (inquiries). The
following parts are also available sepa-
rately: Case (No. H-2507). $12.95;
Transformer Tl (No. M2155), S5.95; PC
board (H-7001) $29.95; IC1 (No. Z-6900),
$12.95; 1C4 (No. Z-2500), $1,90; XTAL1
(K-6031), $1.19; L1 (No. L-0521), $1.50;
L2 (No. L-0520), $4.95.

A complete kit of parts for the infrared
remote control (No. K-3425) is available
for $34.95 plus S2.75 shipping.

California residents must add 6.5%
sales tax. Orders outside U.S. must in-
clude U.S. funds and add 15% of mer-
chandise total for shipping.



of the work of decoding teletext signals.
As we've seen, it requires only the addi-
tion of a power supply, a remote-control
circuit, video and audio input buffers, an
RGB-composite-video encoder, and a
video switch and output buffer to form a
complete set-top decoder. We will build
that outlying circuitry on a main board,
and connect it to the module using four
ribbon cables. We should note here that
there is a third board required by the de-
coder: the remote-control receiver pre-
amp. Of course, we cannot forget the
handheld remote control either. However,
we will not present construction details
for the handheld unit that was shown sche-
matically last month in Fig. 8.



>



CD
00
01



67




FIG. 10— THE HGB-TO-NTSC composite-video encoder is the most complex circuit outside the Mullard
module. IC4 combines the separate R G, B. and Y signals into a standard composite signal. The .After
Hours Sync ( A HS ) output from the module allows the decoder to operate even if the television station
goes off the air.



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The first step in building the decoder is
to make or buy printed-circuit boards.
The foil patterns for the main board and
the remote-control receiver preamp board
are shown in "PC Service." A parts-
placemeni diagram for both boards is
shown in Fig. 12.

Once you have the boards, you should
start by mounting the 22 jumpers on the
main board. Use 22-gauge bus wire and
keep the jumpers tight and flat against the
board. Next, mount all of the resistors,
and then all of the capacitors, using care
to orient the polarized electrolytic and
tantalum rypes correctly.

Mount the four 1N4001 diodes D1-D4,
the 1N4735 zener diode D5 , and the elev-
en transistors, again making certain that
the devices are oriented properly. Install
the 5 IC sockets (but not the IC's). Finally,
solder in the 400-nanosecond delay line
L2 , the chroma coil LI , and the 3.58 MHz
crystal.

Install the RF modulator on the board.
It should be a tight fit; if necessary, twist
the lugs to hold it in place. Solder all four
lugs to the ground plane. Solder the three
input leads closest to the edge of the PC



board (video in, +v, and audio in) in
place, leaving the fourth lead (Channel
Select) free for the moment.

Bolt the power supply transformer Tl to
the PC board, with the primary lugs to-
ward the edge of the board and a ground
lug under the rearmost nut. The three
short angled PC traces behind the trans-
former, with their six pads, are to simplify
AC power connections. The three pads
along the edge of the board are for the
incoming power cord; the other three are
for the connections to the transformer and
the power switch on the front panel.

Solder a short length of 18-gauge wire
from the center of these three pads to the
solder lug under the transformer's mount-
ing bolt. Solder another piece from the
innermost pad to the closest transformer
primary lug. Solder a 6" piece of 18-
gauge wire to the other primary lug, and a
10" piece to the last PC pad. "These two
wires will go to the power switch SI.

The three PC pads behind the four
1 N4001 rectifier diodes are for the second-
ary AC hookup. Connect the innermost of
these pads to the 15 volt tap of the trans-
former, the center pad to the 7 .5 volt tap,



and the last to the volt tap. Solder two 6"
pieces of 22 gauge wire to the and 7.5
volt taps: Those wires will go to S l's inter-
nal lamp.

Now it's time to prepare the remote-
control preamp board. There are a couple
of tricky things about assembling the
board. First, you'll have to be sure that the
LED and the photodiode will be visible
from the front of the decoder. So don't
install them until you're sure about how
you'll mount the board inside the decoder
case. Second, the preamp board needs to
be shielded. So after you install the com-
ponents and the wires that will conneci
the preamp board to the main board, in-
stall four PC terminal posts at the comers
of the circuitry. Bend a piece of tin into a
U shape and solder il to the posts so that it
covers the components on the board. Then
mount a flat tin piece to the bottom of the
board.

Follow the parts placement diagram
(Fig. 12) and wire the channel select
switch, S2, the power cord, the power
switch and the input and output jacks. Be
sure to use coaxial cable for the jacks.

Finally, prepare the four ribbon cables



68




FIG. 11— THE VIDEO SWITCH Is used to select, for display, either a regular TV signal (TVVID) or the
decoded teletext display (TTVID), or a combination of the two for Mix mode. Mote that both RF and
composite video outputs are available.



the supply voltages at the IC pins (note
that the SAA5010/5012 will not have a 12
volt supply until the Mullard module is
connected.) If you have a frequency coun-
ter, check the operation of the MC1377's
oscillator at pin 18 oral pin 8 of IC3. If all
supply voltages are correct and none of
the IC's heats up, the Mullard module can
now be installed.

WARNING: The decoder module is
very expensive and it is subject to static-
discharge damage. Leave it in its protec-
tive sleeve until it is ready for installation,
and handle it only while wearing an anti-
static wrist strap. Thoroughly discharge
all capacitors on the PC board before con-
necting the ribbon cables.

The Mullard module is mounted to the
main board using three bolts and three 'A-
inch spacers. (The mounting holes are not
shown on the parts-placement diagram
because we chose to show the parts-place-
ment diagram for the remote-control re-
ceiver preamp where the module is
usually mounted.) Put the module in place
on the four bolts and secure it with wash-
ers and nuts. Then attach the four cables.
Be sure that the wires from PL1 through
PL4 are connected correctly — the wire
from pin 1 as marked on the parts-place-
ment diagram should go to pin 1 as
marked on the module, and so on.

Power up the decoder again. If any of
the module's IC's gets more than slightly
warm (particularly the two 21I4L2's) shut



to connect the module to the board by
cutting three pieces of 10-conductor rib-
bon cable and separating them to form one
cable each with 4, 6, 9, and 10 conduc-
tors. Separate the conductors at one end
of each about 1" and strip each conductor
1/4 inch.

Solder the two regulators IC6 and IC7
in place, leaving as much of their leads as
possible above the board-only about. 1/16
inch should protrude from the bottom,
just enough for a secure solder joint. At-
tach heats inks and bend the regulators
into position, parallel to the PC board.

Put the four 1/2 inch machine screws
used to mount the Mullard module in
place and secure them with a drop of su-
perglue. Make certain that they remain
straight while the glue sets.

The PC board is now complete. After
checking all of the solder work for bridges
and incomplete joints, the PC board may
be installed in the case bottom, along with
the rear panel. Secure the AC power cord
with a strain relief.

Testing and final assembly

Plug the decoder in and turn it on; the
lamp in SI should light up. Check the
power supply voltages at the regulators'
outputs: they should be within 5% of 5
and 12 volts. Check the voltage at the
power lead of the RF modulator (the only
lead without a plastic insulator): it should





TELETEXT TUNING GUIDE




Service


Station


City


Eiectra


WKRC, Channel 12


Cincinnati, OH


Infotext


WHA, Channel 21


Madison, Wl




WHLA, Channel 31


La Crosse, Wl




WHRM, Channel 20


Wausau, Wl




WHWC, Channel 28


Menomonie, Wl




WLEF, Channel 36


Park Falls, Wl




WMVS, Channel 10


Milwaukee, Wl




WMVT, Channel 36


Milwaukee, Wl




WPNE, Channel 38


Green Bay, Wl


Keyfax


WFLD, Channel 32


Chicago, IL


Metrotext


KTTV, Channel 1 1


Los Angeles, CA



The following services are available on the Galaxy 1 and Satcom 3 satellites, as
well as on any cable-TV system carrying WTBS, SPN, or the Discovery Channel:



Service

Eiectra

Cabletext
Infotext

be within 0.3 volts of 6 volts. Turn the
decoder off and discharge the power sup-
ply capacitors by shorting the regulators*
inputs to ground.

Install the remaining IC's in their sock-
ets, making certain that they are oriented
correctly and that their pins seat properly.
Be careful when handling the (Cs: All but
the MC1377 are MOS devices and arc
subject to static-discharge damage.

Power up the decoder again and check




Channel/Transponder
WTBS/Galaxy 1 TR18 (page 100)
SPN'Satcom 3 TRO
WTBS/Galaxy 1 TR18 (page 201)
SPN/Satcom 3 TR6
TDC/Galaxy 1 TR22 (page 100)



the power off at once, disconnect the
module, and trace the problem on the PC
board. If everything checks out (it is nor-
mal for the two regulator ICs to get quite
warm), you're finished building the tele-
text decoder.



2
>

for the -<



Aligning the decoder

The decoder can be adjusted
most part, without a teletext signal. In
fact, the preliminary adjustments are easi-



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CONNECTIONS TO

REMOTE CONTROL RCVH



FIG. 12 — PARTS PLACEMENT DIAGRAMS for the main board and the remote- control receiver preamp
board. Note that the preamp board Is shown In the area where the Milliard module Is to be mounted.
The preamp board Is mounted at the front of the case so it can "see" the signals from the handheld
remote control and so that you can see LED3.



er with a non-teletext TV broadcast.

Connect the decoder's audio in and
video in inputs to the outputs of the tuner,
satellite receiver, or VCR, and connect
the RF output to the TV's antenna input.
(Even if you will normally be using the
decoder's composite outputs, connect it
via the RF output for adjustment pur-
poses.) Plug in the remote controller and
turn the decoder on.

Set the TV to Channel 3 or 4, and set
the channel select switch on the de-
coder accordingly. Set the tuner to a
strong station, preferably one without a
teletext signal.

Using a Me-inch screwdriver, adjust the
tuning slug in the hole closest to the mod-
ulator's input leads until the best picture is
obtained. Then adjust the modulator bias
control R51 (near the modulator) until the
image is at its best. Some cross adjust-



ment of those two controls may be neces-
sary to obtain the best picture. Adjust the
other tuning slug of the modulator until
the best sound is obtained. Slight adjust-
ments of the TV's fine tuning, color, and
contrast settings may be needed, but pic-
ture and sound should now be perfect.

Press the TT button on the handset.
After a brief delay, a blank screen should
appear, with "P100" in the upper left cor-
ner should. The TV's horizontal hold con-
trol may have to be adjusted slightly.

If the characters are sharply defined, no
further adjustments of the picture are nec-
essary. If the figures are not sharp, press
mix to get text-over-TV mode and repeat
the previous adjustments until both the
text and TV image are sharp.

Return to the teletext (tt) mode again,
and set the tuner to a teletext-broadcasting
station. The "P!00" should almost in-



stantly be joined on the top line by a 6-
digit clock, the day and date, and other
characters. If the top line data does not
appear or is scrambled, use a small screw-
driver to carefully adjust the tall silver coil
on the Mullard module. When the line
appears correctly, stop adjusting.

When the top line appears, it should be
followed almost immediately by the title
page of the teletext service. If you're
lucky, the page will appear without any
errors. More likely, there will be
scrambled lines or random characters
scattered through the page. Wait for a
minute or so to see if the garbage clears
away by itself. If not, adjust the module
coil again, a fraction of a tum at a time,
until the image clears. Wait for 10-15 sec-
onds between adjustments to give the title
page time to come around in the data loop.
continued on page 102



70



]7f^?>



All About FREQUENCY COUNTERS




VAUGHN D. MARTIN



Part 2



USING A FREQUENCY

counter to measure
frequency is simple, but how about using
one to measure phase or risetime? This
month we'll start out by seeing how those
measurements may be made.

Measuring phase

A frequency counter can be used to
measure the phase difference between two
equal-frequency signals. Actually, we
just make a special measurement of
period (time), and then calculate phase
from that time.

Note, in Fig, 15, the values T and Tcb; T
is simply the period of either signal, and
T<|> is the time difference between suc-
cessive positive-going zero crossings of
each signal. You may measure the period
of T in the conventional manner. To mea-
sure T<)>, set the frequency counter up to
operate in the stop/start time-interval
mode. The slop and start triggers should
be AC-coupled and set for a level of 0-
volts DC. The input signals should have
the greatest possible amplitude.

When you have values of T and T<j), you
can calculate the phase difference (c(>) be-
tween the two signals from this equation:

<]> (degrees) = (T4>/T) x 360



PERIOO OF REFERENCE

— T —




REFERENCE PHASE
UNKNOWN PHASE



"COUNTER STOPS COUNTING

1 COUNTER STARTS COUNTING

FIG. 15— THE PHASE DIFFERENCE between
two equal-frequency signals may be measured
with a frequency counter that has adjustable
start- and stop-trigger levels.

Measuring risetime

As shown in Fig. 16, you can use a
frequency counter (in the period mode
again) to measure the risetime (T R ) of a
squarewave or other digital signal. Just set
the start and stop trigger-level controls
to respond at 10% and 90%. respectively,
of the maximum voltage (V M ) of your
signal. For example, standard TTL gates
have a (nominal) high output voltage of
2.4 volts. Measure the risetime by setting
the start control to trigger at 0.24 volts
and the stop control to trigger at 2,16
volts.



Now let's look at some sophisticated
frequency counters and accessories.

The reciprocal counter

The reciprocal frequency counter dif-
fers from the ordinary frequency counter
in that it uses separate registers to ac-
cumulate time- and event-counts. The
contents of those registers are then pro-
cessed to provide outputs that represent
either period or frequency. A simplified
block diagram of a reciprocal frequency
counter, Hewlett-Packard's model
HP5345A, is shown in Fig 17, It works




>

-RISETIME MAY ALSO BE measured "<
with a frequency counter that has adjustable ,5
start- and stop-trigger levels. §>



71



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INPUT 1


INPUT CHANNEL A


— ?-








TIME COUNTER










SWITCHING

AND
MAIN GATE




ARITHMETIC
CIRCUITS














INPUT 2


INPUT CHANNEL B






EVENT COUNTER


■ — *-












ll








"




IDMHz

CRYSTAL

OSCILLATOR




500 MHz
CLOCK




CQUNTEH
DISPLAY



FIG. 17— THE RECIPROCAL FREQUENCY COUNTER provides separate input channels for measuring
time and events.



like this: As long as the main gate is open,
the event counter accumulates pulses from
the external source while the time counter
accumulates pulses from the internal
clock.

Some reciprocal counters allow count-
ing to be externally armed, as shown in
Fig. I8. External arming could be useful,
for example, in measuring the frequency
of a pulsed-RF signal, as shown in Fig.

19. By setting the measurement-time con-
trol to the width of the RF burst, an accu-
rate frequency measurement of the burst
could be made.

In a reciprocal counter, time- interval
measurements are made by counting the
number of pulses between independent
START and stop inputs, as shown in Fig.

20. The resolution is determined by the
frequency of the timebase oscillator. For
example, a 10-MHz clock could provide a
1/10 7 , or 100-nanosecond, resolution.

Some reciprocal counters use direct
gating, as shown in Fig. 2l-o, but direct
gating can cause an unacceptable bias by
shortening the clock pulses, as shown in
Fig. 21-6. Note that part of the clock pulse
is shortened when the gate is opened, and
that part of the clock is also shortened
when the gate is closed.

r rhe solution is to use synchronous gat-
ing, as shown in Fig. 22-a. As shown in
Fig. 22-6, that gating scheme allows the
correct number of pulses to pass through
the main gate and be counted. With the
direct gating circuit above, three pulses
would be counted, but here two pulses
would be counted.

Trigger problems

In typical frequency counters the input
circuitry is optimized for frequency
counting by detecting zero crossings.
That makes it difficult to measure
risetimes, propagation delays, and low-
periodic-rate pulses because of the limited
trigger-level range used (typically one volt
or less). At best the LEVEL control varies
the center of the hysteresis band, and at
worst it is offset by several tens of milli-
volts. Figure 23 illustrates how the time
interval actually measured can be dis-
torted by improper triggering.

Sometimes you can compensate for the



FROM INPUT
AMP-TRIGGER



COUNTING
REGISTER



MM mi



MAIN
GATE



ARMING
GATE



COUNTED

CLOCK

INPUT



_TL



ARMING
FLIP-FLOP



EXTERNAL
ARMING

PULSE



FIG. 18— INPUT-ARMING CIRCUITRY IS USED IN
a reciprocal counter for specialized measure-
ments, as shown in Fig. 19.



INPUT

signal"



INITIATES DIRECT MEASUREMENT
DF INPUT PULSED RF SIGNAL



4ft



EXTERNALLY
APPLIED
ARMING
TRIGGER



WIDTH DETERMINED BY
MEASURFMFNT TIME CONTROLS



u



GATE
START/
STOP
OUTPUT



FIG. 19— MEASURE PULSED RF ACCURATELY
by using start and stop pulses to limit counting
to the width of the burst.



GATE OPENS



GATE CLOSES




_TL



CL0CK iiiiuiiiiuiiii iiiinmiiiiiiim

ACCUMU LATE ID H1IH11

CLOCK PULSES



ACCUMULATED
COUNT



FIG. 20— INDEPENDENT START AND STOP
pulses allow a reciprocal frequency counter to
measure time interval accurately.



ambiguity in the trigger point by using
"hysteresis compensation." in which a
DC voltage equal to Vi the hysteresis band
is added to (in the case of a positive-going
signal) or subtracted from (in the case of a
negative-going signal) the selected trigger
level or reference voltage.

Rather than hysteresis compensation,
the lime-interval probe solves the prob-
lem of trigger-level ambiguity by using an
automatic calibration scheme. The user
grounds the probe to be calibrated and
then presses a front panel switch. That
causes the reference voltage V R to de-
crease in a stair-step fashion in one-mV
steps until the device triggers. For nega-
tive slope calibralion, that voltage in-
creases.

The system then uses that value of V R
to adjust itself so that the actual trigger
voltage corresponds to the trigger level
selected by the user. Recalibration. when
slopes or probes change, assures constant
triggering accuracy. Any trigger voltage
from -9.99 volts to +9.99 volts may
also be selected, in ten-mV steps, by set-
ting front-panel thumbwheel switches.

The time-interval probe has other ad-
vantages including high input impedance
(one megohm) and low input capacitance
(10 pF). Ordinary high -impedance probes
have about 40 pF of capacitance, and, at
high frequencies, delays through the
probe, cable, and circuitry can cause an
inaccurate determination of time interval.

For example. Hewlett-Packard's
HP5363B uses two DAC's (DigitaJ-
to-j4nalog Converters) for setting trigger
level, and for self calibration. The main
DAC. controlled by a thumbwheel
switch, supplies the +9.99 to -9.99V
trigger level voltages. The offset DAC,
used to compensate for residual offset
voltages in the two probes, is initially off-
set from the main DAC by + 75 mV. and it
may vary from +75 mV to -75 mV in
one-millivolt steps.

When calibrating for a positive slope,
the lhvel calibrate switch clears both
DAC's. then internal calibration circuits
sweep the offset DAC's voltage output
from + 75 mV downward in one-millivolt
steps until the input channel just switches.
That voltage is stored digitally and then it
is added to the thumbwheel-controlled
DAC to give the true trigger voltage used
for subsequent measurements. When cal-
ibrating for a negative slope, the process
is similar except that the offset DAC starts
from -75 mV and scans upward.

Visual trigger indication

A scope marker gives us a visual in-
dication of the actual voltage at which a
frequency counter triggers. We will ex-
amine three types of markers: dot. gate,
and squarewave markers.

The dot marker is a 100-ns pulse initi-
ated by an input channel's triggering. For
example, the dots on the waveform shown



72




FIG. 21— DIRECT GATING (a) can cause count-
ing errors (b).



ARMING
FLIP-FLOP



GATE
CONTROL
FUP-FLOP



START-*
STOP-*

CLOCK —



*■ D



pCLK



COUNTED
SIGNAL



GATE




START



STOP



ARMINR I

FLIP-FLOP

clock -n_n_rLrLn_n_n_
j 1



_n_n_



GATE_
CONTROL
COUNTEO^
SIGNAL



FIG. 22— SYNCHRONOUS GATING (a) elimi-
nates counting errors (b) suffered by direct gat-
ing (see Fig. 21).




SELECTED

TRIGGER
LEVEL, V?



I MEASURED
■*- TtME -
INTERVAL

FIG. 23— TIME-INTERVAL MEASUREMENTS
can be distorted by improper triggering.



START POSITIVE SLOPE

TRIGGERSAT +0.7 VOLTE




STOPNEGATIVE SLOPE
-0.5 VOLTS




4 WX-A^V-A


/ W v v


*7WV^A A A


w 7v V V V


-^WVA^ A


w ^vA/ V v7^


m AAA^^


ov / V V V V



START MARKER TRIGGERS
ON POSITIVE SLOPE



_ STOP MARKER TRIGGERS
ON NEGATIVE SLOPE



COMBINED MARKERS



■ GATE MARKER FOR ABOVE CONDITIONS



0.5 ms

b

FIG. 24 — DOT- AND GATE-MARKERS provide visual indication of trigger level. At a ere shown the
trigger levels that produce the dot-marker outputs shown in the upper four traces at b. At c is shown
the trigger range that is displayed In the gate-marker trace at the bottom of b.




FIG. 25— THE HETERODYNE DOWN-CONVERTER is one way of measuring the frequency of micro-
wave signals as high as 20 GHz.



in Fig. 24-fl indicate the stop- and start-
trigger levels. That puise is used to inten-
sity-modulate a scope, so it appears as a
bright dot on the screen of the scope, as
shown in the upper trace of fig. 24-fc.

The gate marker is similar to the dot
marker, but it provides continuous output
between the start and stop trigger
pulses. The fuzzy portion of the waveform
in Fig. 24-f indicates that the same input-
voltage range will trigger the gate marker
as triggered the dot marker in Fig. 24-a.
Its appearance on the scope would resem-
ble the lower trace in Fig. 24-6.



The squarewave marker usually ap-
pears as an inverted replica of the Schmitt-
trigger output of the frequency counter. It
may be viewed on a multi-trace scope
along with the input signal to verify that
the input circuitry is triggering properly.

Microwave frequency counters

To understand how microwave frequen-
cy counters work, recall that a frequency
counter has a gate that regulates the flow
of counting pulses. The switching speed
of common gates is limited to signals far
short of the microwave region (for our



purposes, about 3 Ghz). So how can we
measure 10-GHz signals? Basically, there
are four methods of measuring the fre-
quency of a microwave signal: 1 ) Prescai-
ing, which is effective to about 1.5 GHz;
2) Heterodyne down-conversion, good to
20 GHz; 3) Transfer-oscillator tech-
niques, good to 23 GHz; 4) Harmonic-
heterodyne converters, which seem to
yield reliable results as high as 40 GHz.
Prescciling, as we discussed earlier in
this article, is accomplished by inserting a
divider ahead of the frequency counter's
input. To compensate for a division by n,



>

3



73



SAMPLER




VIDEO
AMP



FROM TIMEBASE I
I



PHASE
DETECTOR



Vamp



video

AMP 2



1



REFERENCE
OSCILLATOR



QUADRATURE
DETECTOR



r* MIXER



r-3 y~-



COUNTING
REGISTER



MAIN
GATE



MAIN GATE
FLIP-FLOP



DISPLAY



TIMEBASE
DIVIDERS



N COUNTER



FIG. 26 — THE TRANSFER OSCILLATOR can measure microwave Signals as high as 23 GHz.



INPUT

o



SAMPLER




VIDEO AMP



-i — *■

I
l



SCHMITT

TRIGGER



E>3



BAND-PASS

FILTER



SYNTHESIZER



I



SIGNAL I

DETECTOR I



77



TIMEBASE
OSCILLATOR




COUNTING
REGISTER



DISPLAY



^>



AA



v



PROCESSOR



FIG. 27— THE HARMONIC-HETERODYNE CONVERTER is a hybrid of the two circuits shown in Fig. 26
and Fig. 27. It can measure frequencies as high as 40 GHz.

TABLE 3— MICROWAVE CONVERTERS





Characteristic


Heterodyne

converter


Transfer oscillator


Harmonic
heterodyne

converter




Frequency Range


20 GHz


23 GHz


40 GHz




Measurement Speed


1 50 ms acquisition

1/R gate


150 ms acquisition
fi'R gate


350 ms acquisition
1/R gate




Accuracy


Timebase limited


Timebase limited


Timebase limited


CO


Sensitivity/
Dynamic Range


30 dBm/35-50 dB


-35dBnV40dB


- 30 dBm'35-50 dB


o

z
o


Signal-to-Noise
Ratio


40 dB


20 dB


20 dB


o

LU


FM Tolerance


30-40 MHz
peak- peak


1-10 MHz
peak-peak


10-50 MHz
peak-peak


til


AM Tolerance


Less than 50%


Greater than 90%


Greater than 90%


o
□
<


Amplitude
Discrimination


4-30 dB


2-10 dB


2-10 dB



the counter can either leave its gate open n
times as long, or it can multiply the gate
register's contents by n.

Heterodyne down-conversion entails
mixing the incoming microwave signal
with the output of a high-stability os-
cillator. Doing that yields a difference fre-
quency that is within the usual 500-MHz
frequency-counter bandwidth. The basic
process is illustrated in Fig. 25. The time-
base oscillator is fed not only to the main
gate flip-flop, as in the basic frequency
counter, but to a frequency-multiplier that
generates a "comb line" of signals spaced
at regular intervals out to the maximum
range of the frequency counter.

One line of the comb is selected by the
microwave filter and directed to the mixer.
What emerges from the mixer is a video
signal that is equal to the difference be-
tween the two input signals. That signal is
then amplified and sent to the counter
circuit. The display shows the sum of the
video and the input frequencies. The sig-
nal detector serves to detect the correct
comb-line value.

The transfer-oscillator technique
phase-locks a low-frequency oscillator to
the incoming microwave signal, as shown
in Fig. 26. The low- frequency oscillator
can be measured in a conventional man-
ner, so the microwave frequency can be
determined from the harmonic rela-
tionship between the input signal and the
low-frequency oscillator. After lock is
achieved, the input frequency can be cal-
culated:

F x = nFi - Fifi
The harmonic-heterodyne converter is
a hybrid of the two techniques just dis-
cussed. A block diagram is shown in Fig.
27. The harmonic- heterodyne converter
acquires microwave signals in a manner
similar to the transfer oscillator, but it
measures frequency in a manner similar to
the heterodyne converter. Frequency is
determined by the processor's multiply-
ing the synthesizer frequency by n and
adding the result to the video frequency.
The input frequency can be calculated as:

Fx = nF s + F| F

As you can see, that is similar to the
way the heterodyne converter works, in
that the nth harmonic of a stable oscillator
is mixed with the input to produce a video
difference frequency.

Most microwave frequency counters
can measure frequency- modulated sig-
nals, but the heterodyne converter and
harmonic-heterodyne frequency counters
have a distinct advantage in making that
measurement, as shown in Table 3. Also
shown in that table is the fact that the
heterodyne converter has a limited toler-
ance to AM due to its AGC circuitry. The
transfer oscillator and harmonic-hetero-
dyne converters do not suffer that limita-
tion, and they can measure a carrier at
- 10 dBm with 95% modulation. R-E



74



PC Service



One of the most difficult tasks in build-
ing any construction project featured in
Radio-Electronics is making the PC
board using just the foil pattern provided
with the article. Well, we're doing some-
thing about it.

We've moved all the foil patterns to this
new section where they're printed by
themselves, full sized, with nothing on the
back side of the page. What that means
for you is that the printed page can be
used directly to produce PC boards!



Note: The patterns provided can be
used directly only for direct positive pho-
toresist methods.

In order to produce a board directly from
the magazine page, remove the page and
carefully inspect it under a strong light
and/or on a light table. Look for breaks in
the traces, bridges between traces, and in
general, all the kinds of things you look for
in the final etched board. You can clean up
the published artwork the same way you
clean up you own artwork. Drafting tape



and graphic aids can fix incomplete traces
and doughnuts, and you can use a hobby
knife to get rid of bridges and dirt.

An optional step, once you're satisfied
that the artwork is clean, is to take a little
bit of mineral oil and carefully wipe it
across the back of the artwork. That helps
make the paper transluscent. Don't get
any on the front side of the paper (the side
with the pattern) because you'll con-
taminate the sensitized surface of the
copper blank. After the oil has "dried" a




-4-3/16 INCHES-



BUILD OUR LITTLE LEAKAGE CHECKER and find the leaky capacitors that have been
eluding your capacitor tester. The pattern for the PC board is shown here; the story begins on
page 51.



1



75






PC Service



bit— patting with a paper towel will help
speed up the process — place the pattern
front side down on the sensitized copper
blank, and make the exposure. You'll
probably have to use a longer exposure
time than you are probably used to.

We can't tell you exactly how long an
exposure time you will need but, as a start-
ing point, figure that there's a 50 percent



increase in exposure time over litho-
graphic film. But you'll have to experiment
to find the best method for you. And once
you find it, stick with it. Don't forget the
"three C's" of making PC boards— care,
cleanliness, and consistency.

Finally, we would like to hear how you
make out using our method. Write and tell
us of your successes, and failures, and



what techniques work best for you. Ad-
dress your letters to:



Radio-Electronics
Department PCB

500-B Bi-County Blvd.

Farmingdale, NY 11735



■3

z

a
x

-U

_i

6

5

I



76



-I—

HUH! !




-3-1/16 INCHES



THE REMOTE CONTROL PRE AMP BOARD for the teletext decoder Is
shown here Cull size mirror image.



PC Service







PC Service









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□

78



Electronics 0Tr]M°/^






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2
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1

79



Satellite TV



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Scrambling update

IT FINALLY HAPPENED. ALL SIGNALS

transmitted by HBO and sister ser-
vice Cinemax after midnight, Janu-
ary 15th will be scrambled. Gone
forever is the free programming
enjoyed by more than 1.5 million
satellite-dish owners since TVRO
became popular in the late 1970's.
Good riddance.

When satellite dishes began to
sprout up all over America some
seven years ago, you could count
on HBO to provide the best uncut,
un-interrupted display of late-run
movies of all the cable services. So
the ability to receive HBO was jus-
tification enough for the purchase
a TVRO system. The sentence "I
have a dish" was almost always fol-
lowed by "And I get HBO."

In theory, anyone who wishes to
continue receiving HBO can do so
by adding a descrambler to his or
her present system. The de-
scrambler is shown in Fig. 1; it is
called Videocipher, and it was de-
signed by the Linkabit division of
M/A-Com, During 1985, HBO
provided, free of charge, more
than 10,000 Videocipher de-
scramblers to authorized affiliates.
And for home viewers, several
less-complicated versions of Vid-
eocipher have been introduced.

The devices are available in two
models: the VC2000E and the
VC2000E/B. You can purchase a de-
scrambler for under $400, and, for
an extra charge, sign up for HBO,
Cinemax or both. You can sign up
by calling (800) 845-2748 and giving
the operator your Videocipher se-
rial number and a VISA or Master-
Card number. Or you may contact
a local distributor.

If you sign up for descrambling

* Editor-in-chief, Coop's Satellite Digest




FIG. 1



directly from HBO, it will cost you
$12.95 per month for either HBO
or Cinemax, or $19.95 per month
for both. However, it seems that
you can get the same service from
a local distributor for as little as
$12.95 per month for both ser-
vices.



TVRO dealer "Starter Kit"
available

Bob Cooper's CSD Magazine has ar-
ranged with a number of TVRO equip-
ment suppliers to provide a single-
package of material that will help intro-
duce you to the world of TVRO dealership.
A short booklet written by Bob Cooper
describes the start-up pitfalls to be avoid-
ed by any would-be TVRO dealer, in addi-
tion, product data and pricing sheets from
prominent suppliers in the field are in-
cluded. That package of material is free of
charge and is supplied to firms or individu-
als in the electronics service business as
an introduction to the 1984/85 world of
selling TVRO systems retail.

You may obtain your TVRO Dealer
Starter Kit free of charge by writing on
company letterhead, or by enclosing a
business card with your request. Address
your inquiries to: TVRO STARTER KIT,
P.O. Box 100858, Fort Lauderdale. FL
33310. That kit not available to individuals
not involved in some form of electronics
sales and service.




BOB COOPER, JR.

SATELLITE TV EDITOR



How they work

The VC2000E descrambler ac-
cepts a 70-MHz signal from a TVRO
receiver (which must have a
straight-through 70-MHz connec-
tion). The descrambler demodu-
lates the 70-MHz signal and then
recovers the descrambling codes
from the baseband video. The dig-
itally-encrypted audio signal is
also recovered from the baseband
video. The descrambler can prop-
erly decode fairly "sloppy" input
signals.

The VC2000E/B is not so forgiv-
ing. That unit performs the same
decoding, but it uses the base-
band video signal rather than the
70-MHz IF signal. The VC2000E/B
requires a relatively pure base-
band signal. The signal must have
little phase shift and group delay;
other video parameters are equal-
ly tight. The problem is that few
currently-available receivers can
readily supply signals of that sort.

There is no difference in price
between the two units, even
though the VC2000E is more com-
plex, uses more parts, and costs
more to build than the VC2000E/B.
Unfortunately, the VC2000E was
not made available at the same
time as the VC2000E/B, and the
marketplace is confused about
why only some receivers work
with the descramblers initially
made available.

Problems

HBO had promised that, when
full-time scrambling began, sup-
pliers would have an adequate
supply of descramblers in the dis-
tribution pipeline. Unfortunately,
they didn't.

In fact, fewer than 1,000 de-



ed



scramblers (all VC200QE/B's) were
actually in distributor's hands on
January 15th. Inaddition,thosede-
scramblers worked with few re-
ceivers. HBO blamed its supplier,
M/A-Com, for the snafu, and M/A-
Com refused to answer desperate
queries from either users or sup-
pliers. All things considered,
scrambling did not get off to a very
good start.

In fact, M/A-Com has provided
no hard information on the de-
scrambler product for over a year.
Meanwhile, HBO was advertising
their scrambling plans for months,
and they advised TVRO owners to
contact their local M/A-Com dis-
tributors for additional informa-
tion and to order descramblers.
HBO's failure to provide dis-
tributors and dealers with any in-
formation has left luckless TVRO
owners with nothing. And HBO
had originally promised that
things would get off to a smoother
start.

So the TVRO industry is in-
censed by the lack of concern
shown by both HBO and M/A-Com
about the scrambling switch-over.
Congressional hearings requested
by SPACE (the Society for Private
And Commercial farth stations,
the industry trade association) are
scheduled to occur around the
time you read this report. At stake
here is the way consumers (i.e.
TVRO owners) are to be treated by
cable programmers. Those pro-
grammers, to date, have shown
considerable reluctance to deal
with TVRO owners at all.

Bootleg descramblers

The truth is that bootleg de-
scramblers are already on the
market. However, the ones I have
seen so far recover only the video
portion of the transmission. That's
no great trick, since the Vid-
eocipher system merely inverts
the polarity of the baseband video
signals and retards the sync signal.
That's similar to the way that many
of the terrestrial (subscription TV)
systems scramble their signals.
That system does not pose much
of a obstacle to someone deter-
mined to unscramble a transmis-
sion. So far so good.

Audio recovery, however, is an-
other matter. It's difficult for the
following reasons. Audio is sent



digitally. That fact alone prevents
use of a simple demodulator.
Next, the digital pulse sequence is
varied using a key that is transmit-
ted with the digital audio. The key
itself is also encrypted ; it's part of a
master key that is burned in a
custom set of IC's inside each Vid-
eocipher. The balance of the mas-
ter key is transmitted with the
signal. The key/master-key infor-
mation is changed several times
per minute, so unlocking the key
sequence at any point in time only



provides the user with momentary
audio recovery. Hence it seems
unlikely that a simple method of
recovering Videocipher audio will
be developed soon.

Another point is that if M/A-Com
has its way, eventually all cable-TV
transmissions will use the same
scrambling technique. In that
scheme, every descrambler is ad-
dressable by the program supplier
who can lock and unlock individu-
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81



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all channels delivered to a home
would be equipped with a com-
bination converter/decoder with
cable-operator control over which
homes receive which services.
That addressable system is the pay-
TV delivery system of the future,
and it's operating now in the satel-
lite portion of the pay-TV distribu-
tion system.

Other problems

When HBO began scrambling
there were some bugs. Early home
subscribers discovered several
things:

? It was impossible to subscribe
to just HBO; consumers received
Cinemax whether they wanted it
or not. However, if a subscriber
had not ordered Cinemax, HBO
decided not to charge for that ser-
vice in that situation.

? The HBO descrambler also de-
coded test transmissions from it's
competitor, Showtime, as well as a
new scrambled Pay-Per-View first-
run movie service carried on satel-
lite.

Those unintentional freebies
were caused by a malfunctioning
addressing computer in HBO's
master control system.

And you might find it interesting
to know that there are fail-safe rou-
tines built into the M/A-Com sys-
tem in the event of a major
equipment failure. For example,
suppose the whole addressing
portion failed at the satellite up-
link. All descramblers in the sys-
tem — there could be millions of
them — turn off, so only scrambled
audio and video would be re-
ceived. HBO could then reactivate
all decoders in the system en mas-
se using a special "open" com-
mand. Then, as the addressing
computer was repaired, individual
descramblers could be re-ad-
dressed and the appropriate ser-
vices enabled or disabled.

In sum, 1986 is going to be a
shake-down year for an exciting
new technology. There have been
glitches in the system already, but
none appear to be sufficiently se-
rious to cause the system to be
abandoned at this late date. Show-
time and The Movie Channel are
scheduled to begin scrambling in
late spring or early summer. We'll
keep you up to date about what
happens. R-E



82



Robotics



Heath's new Hero




MARKJ. ROBILLARD,

ROBOTICS EDITOR



THE HEATH COMPANY (BENTON HAR-

bor, Ml 49022) has finally released
the latest member of its family of
Hero robots. The new addition,
Hero 2000, is shown in Fig. 1; he
differs significantly from his pred-
ecessors. For one thing, Hero2000
is 32.4 inches tall and weighs about
78 pounds — considerably greater
than Hero 1. The additional size
and weight makes Hero 2000 much
more powerful than Hero 1; let's
get an idea of what that power con-
sists of.

Mechanical features

Hero 2000's ability to move is
provided by a two-wheel drive sys-
tem that uses several casters for
balance. Each drive motor is cou-
pled via optical feedback into a
closed-loop system that provides
precise control. It's interesting to
note that, if the robot is moved
from a rest position, it immediately
attempts to return to the point of
origin.

Heath can supply an optional
arm for Hero 2000, and it's simply
exquisite. Forget you ever laid
eyes on Hero Ts arm. The new one
is as precise as anything currently
available. It's driven by the same
closed-loop system that is used in
all the robot's joints. The driving
mechanism is a combination of
chains and cables. Although the
arm can lift only one pound, it can
do so even with the arm fully ex-
tended. The weight limitation is
due more to safety factors than
technical ones; Heath has re-
stricted Hero 2000's weight-lifting
ability in order to reduce the pos-
sibility of accident. For example, if
the arm were too strong, a child's
(or adult's!) finger could be se-
vered in the robot's elbow joint if it



were accidentally inserted there.
Heath should be commended for
showing such a responsible engi-
neering decision.




FIG. i



The gripper is composed of two
parallel jaws. However, removable
finger pieces are provided, and
that allows custom grips to be in-
serted. Heath intends to provide a
variety of fingers in their training
courses. In addition, there is a
unique touch/force-sensing
mechanism built into the gripper.
In fact, it's so special, that Heath
has patented it.

Hero 2000's head does not rotate
(unlike Hero Vs head). Instead, the
entire torso, from the waist up, ro-
tates. That gives the arm another
degree of freedom. A hex keypad
is mounted in the head for manual
entry of data or commands; also,
you can move the robot by press-
ing direction keys in the head.
There is a "status indicator" area of
the head that has eight user-de-



finable LED's. They can be used to
show the progress of your pro-
gram, to add "personality" to your
robot, etc.

The internal gel-cell battery can
be recharged using a clever
charger that Hero 2000 can find on
its own. The recharging hardware
is provided with the basic robot,
but the software will be sold sepa-
rately.

Inside the torso rests the heart
of the system. As shown in Fig. 2,
there is a twelve-slot 5100-like
motherboard. It is through that
bus that all the electronics of the
robot communicate. Even the CPU
card is plugged in the bus, so it is
conceivable that you could use a
different microprocessor to con-
trol your Hero 2000 than the one
supplied. In the basic system only
three of those slots are used, and
that leaves nine to play with!




FIG. 2



Robot brains

The main microprocessor is an
8088— the same as in the IBM PC.
Is the Hero 2000 IBM compatible?
Heath officials are reluctant to an-
swer that question, but I got a
glimpse of a Hero 2000 running a
system that printed out "MS-
continued on page 84



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84




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DOS." That brings up another
thing. Hero 2000 will be offered
with an optional disk drive. The
controller will support four drives,
but only two can fit in the torso.

Helping out the 8088 are 11—
that's right, 11—8042 eight-bit slave
microprocessors. They perform
the tasks of servo control and sen-
sor management. Most auxiliary
tasks are distributed among those
processors, and that gives the 8088
time to do the really complex tasks
like those involved in artificial in-
telligence. In addition, the Hero
2000's built-in 24K of battery-
backed-up CMOS RAM can be ex-
panded to as much as 576K!

The sensor compliment is as fol-
lows. There are two Polaroid-like
ultrasonic rangers on board. (See
the "Robotics" columns in the
November and December 1985 is-
sues of Radio-Electronics for a dis-
cussion of ultrasonic rangers.)
They're "intelligent" through use
of the 8042 's. The main ranger is



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located on the robot's head. It is
connected to a stepper motor that
can rotate it 360°. The second sen-
sor is located on the front of the
base.

Integrally mounted with the ul-
trasonic sensor on the Hero2000's
head is a light sensor. It too can
measure light levels in a 360° area.
A sound-level detector can mea-
sure ambient sound within the
range of normal human hearing. A
temperature sensor can measure
temperatures from 60°F to 90°F.

Voice communication is vastly
improved tn the new Hero. The
new voice synthesizer is abso-
lutely amazing. They have a demo
that makes the robot appear to
breathe! You've got to hear it to
believe it!

You can communicate with the
robot in two different ways. There
is a built-in bi-directional RF link,
and an RS-232C port on the CPU
card. A portable console that in-
cludes a full QWERTY keyboard
and a two-line 40-character LCD
display is used to talk with Hero
2000 via the RF link. You can use
that remote terminal to program
the robot just as if you were typing
at a directly-connected terminal.
There is also an RS-232C port on
the console so that a different
computer can communicate with
the Hero 2000 via the RF link.

Programming Hero 2000 is a
dream. The robot comes with a
full-featured implementation of
BASIC that includes statements
and functions that allow easy con-
trol of the robot's motion and sen-
sors. One nice feature of Hero
BASIC is that it allows interrupt
control. In addition, you can call
machine-language subroutines for
those times when BASIC is just not
fast enough.

Conclusions

Now that you're all excited,
here's the bad news. A kit that in-
cludes everything mentioned
above except a disk drive goes for
just under $3000. I hope that didn't
spoil your enthusiasm. Actually,
several kits are offered starting as
low as $1999.95. To find out
whether the Hero 2000 is really
worth it, I suggest that you visit
your nearest Heath store and ask
for a demonstration. I'm sure
you'll be impressed. R-E



Antique

Radios



Contributions by hams and SWL's



COLLECTING ANTIQUE RADIOS IS A FAS-

cinating hobby for everyone.
Younger collectors, to whom an
"antique" radio is a set from the
1950's, can learn much about the
history of radio, and more senior
collectors can appreciate the
amount of change the radio indus-
try has gone through in less than a
century. So, for the benefit of our
younger readers, we'll discuss
equipment from their era occa-
sionally. Today, for example, our
antique of the month is an inter-
esting set from the195G's; after dis-
cussing it we'll go on to talk about
how ham operators and SWL's in-
fluenced the development of ra-
dio.

The antique of the month

The Belmont Model 5-D-128 Se-
ries A, shown in Fig. 1, is our (to-
be-restored) antique of the
month. As you can see, the case
style of that radio is considerably
different than that of the radios we
usually display here. But its varia-
ble tuning control and five push-
buttons for automatic station
selection make the Belmont an in-
teresting relic of its period.

Hams and SWL's

We can't discuss antique radio
without mentioning amateur radio
and shortwave listening. Senior
readers of this column are well
aware of the importance of the
connections between the de-
veloping radio industry and hams
and SWL's. Hams were commu-
nicating via the airwaves well be-
fore the 1920's; they used spark-
gap transmitters for that com-
munication. The U.S. Navy had to




FIG. 1



exercise considerable control over
those devices.

During the war (WWI), all ama-
teur radio transmitting and experi-
menting had to be suspended. But
after the war ended, radio re-
turned to its pre-war status. And
that's when things really began to
mushroom. Again, during WWII
radio experimenting was forbid-
den, but afterwards a new surge of
growth brought things to a higher
level than ever before.

In the early period, there was
some discussion about whether
listening devices should be li-
censed. Finally licensing require-
ments were dropped after it was
decided that receiving antennas
didn't interfere with other radio
signals. That turned out to be a
good decision; otherwise there
would have been few listeners for
KDKA's famous broadcasts — or for
anything else.

While everyone is familiar with
the way hams help out in a time of
emergency, their contributions to




RICHARD D. FITCH

CONTRIBUTING EDITOR



the advancement of radio are
often overlooked. The number of
amateur radio operators con-
tinued increasing through the
1940's when their ranks grew to
some 50,000. That number in-
cludes only the licensed oper-
ators; you might multiply that
number several times to include
all those who just listened to
shortwave signals. The reason is
that, while amateur radio was sus-
pended during WWII, shortwave
listening became even more pop-
u I a r.

By the 40's, most commercially-
sold receivers had shortwave
bands. Many of us recall picking
up heart-rending messages from
foreign countries on our home ra-
dios during the war years. An oper-
ator would beg for help in broken
English, and then his signal would
fade as enemy troops overran his
area.

Amateur radio resumed, more
popular than ever, when hostilities
ceased. However, shortwave lis-
tening didn't fare so well; the lis-
tening public soon found other
interests including Hi-Fi and ster-
eo, FM radio, CB, and television,
of course.

Returning to the early 1920's, in-
terest in receiving shortwave also
faded after the end of the first
World War. There were enough
regular broadcast stations on the
air to keep the listener occupied,
although the shortwave bands
were still busy for those inclined to
listen. By the late 1920's, few new
receivers (most of which had elab- s
orate, artistic cabinets) could re- ^
ceive a shortwave band without ?
some sort of adapter. Aesthetic §>



considerations were put to good
use later on in the 30's, when intri-
cate turning dials marked the
shortwave (and other) bands.
Those dials were surely a selling
point for the radio salesmen of the
thirties.

However, after six or seven years
of listening to regularly-scheduled
broadcasts, people's interest in
shortwave began to revive. Alert
manufacturers then began to offer
shortwave adapters, sometimes in
kit form, that allowed shortwave
signals to be received on broad-
cast-band radios. At first, band se-
lection was accomplished by
plugging in different coils, rather
than by rotating a switch.

Early radio enthusiasts usually
made whatever parts they could,
and that included winding their
own coils. Perhaps they bought
the coil form and the wire, but a
pre-wound coil was seldom pur-
chased. Some built coils out of old
tube bases and sockets. Or the
cardboard cover from a flashlight
battery could be used as a coil
form.

Sometimes it wasn't clear which
coil you needed. Frequency as-



signments were varied often. In
the early days, the Department of
Commerce assigned those bands.
Later it was the duty of the Federal
Radio Commission, which came to
life in 1927.

Band scrambling

At the end of 1921, entertain-
ment programs (music shows, for
example) were consigned to 360
meters, and public service reports
to 485 meters. A year later, "high-
powered" stations (over 500 watts)
were assigned to one band, and a
year later, they were re-assigned to
375-545 meters. Low-powered sta-
tions were placed on the 230-300
meter band.

Later, because of overcrowding,
a problem developed at the low
end of the dial. Broadcast stations
there had to monitor nearby fre-
quencies for emergency messages
from ships and planes. If anything
was detected, the station had to
stop transmitting until that fre-
quency was clear. By 1925 the
broadcast band was extended to
200 meters. That gave it a total
range of 200-545 meters.

Since most receivers sold in the



late 20's could receive the broad-
cast band only, adapter kits and
plans were plentiful. However,
many of those adapters didn't
meet expectations. Some simply
didn't bring in the desired signals,
and others worked, but only with
certain radios. Disappointment in
those adapters surely led to loss of
interest in shortwave listening.

A manufactured set (or even a
suitable kit) that covered both the
broadcast band and various short-
wave bands was needed. A radio
made by National Co., of Maiden,
Massachusetts, was one which
met that need.

The Thrill Box

National's receiver tuned the
entire 15-550 meter range, which
included the most often listened
to shortwave bands, as well as the
broadcast band. Complete battery
operation was recommended for
that early (about 1929) four-tube
receiver. The tubes include a 222, a
200A, a 240, and a 171A.

Working backwards from the
output stage, first comes the 171A,
a power tube. The loudspeaker is
connected directly to the plate cir-



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CONTENTS



Vol. 3 No. 5



May 1986



7 Using A TI-99/4A Keyboard On A Sinclair ZX-81

All it takes is a little simple modification, some fancywork with your
soldering iron, and you've got it cold. Robert Grossblatt

11 Your Commodore-64 Can Remote Control your Home.

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15 Computer-Designed Power Supply Components

Cut-and-try becomes a thing of the past as you feed the parameters
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3 Editorial

4 Letters

4 Computer Products






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\7


34


22


14


10


34


2T


IS


20


+0


26


16


11


?


27


17


22


44


20


18


1*


40


31


1?


23


50


32


20


26


32


13


21


28


56


3*


22


If


5S


37


23


zo


60


3f


24


SI


64


41


25


33


66


42


2&


34


68


4*


17


34


72


M


28


37


74


4B


IV


3B


7i


4V



See Page 15



ON THE COVER

Here's the completed Remote Controller to automate your home.
We imposed on the author to get his photographed and he
couldn't wait to get it installed once again! For additional
information, see page 11.



COMING NEXT MONTH

It's "alphabet soup" time, with a story on GPI8, the General Purpose
Interface Buss, and then we've got a story on LAN, Local Area
Networking. To round out the issue, you'll be reading a most-
interesting piece on what can happen when lightning strikes, as far
as your computer equipment is concerned. It happened to one of
our authors! Of course, you'll also enjoy all of the regular
departments, including our Editorial, the Letters Column, and the
latest in Computer Products,




2 ComputerDigest — MAY 1986



EDITORIAL



Who are you fooling?



■There are some basic, fundamental tenets in engineering that we are
forced to live with. The first of these, is that you "don't get something for
nothing." Whatever you gain must be paid for with a sacrifice elsewhere. In
computer design, for example, if you want the miniaturization offered by a
liquid crystal display you can't at the same time, have the easy readibility of
a cathode ray tube. And if you want low cost you'll usually give up several
nice little options that you might also like to have. After all, these things do
cost money and somebody has to pay the piper.

A friend of mine called last night to tell me that his new hard disk system
was now installed and working. From his enthusiasm, as he read the display
there was no question that he was delighted with the seemingly unlimited
workspace he had attained. And the numbers were indeed impressive.
Even with his operating systems on the disk, there was still more than ample
room left for at least a year's worth of work, and I knowth\s guy really cranks
it out. Frankly it left me feeling a trifle envious. It also made me think. The
more convenience you build into your system, the less effort you have to
exert. Unfortunately, our own "Murphy's Law" that you don't get something
for nothing, was working here too. Hard disk systems cost. There are other
things we'd like to add to our own system. Things have to be prioritized.

Frankly I'm as much a sucker for a bargain as anybody else. Offer me a
"deal," and you've probably got me hooked. But in retrospect, there sre few
deals that are worthwhile, and these come far between. You want to buy
the most for your money the seller wants to give as little as possible to
improve his own profit picture. Nobody is in business on an altruistic basis.
You know how much you've got to spend; the seller knows what he has to
offer He may show you something with fewer of the "extras" that will save
you some bucks, and you probably figured to add the extras later on.

That's why we figured out a new version of the Law... "Buy the best you
can afford and make your first expense your last,"



j/flsfrr



?




Byron G. Wels
Editor



Computer Digest is published monthly as an insert in Radio- Eleclronics magazine by Gernsback Publications,
Inc., 500-B Bi-Counly Blvd., Farmingdale. NY 11735 Second-Class Postage Paid at New York* NY. and
additional mailing offices. Copyright G 19B6 Gernsback Publications, Inc. All rights reserved. Printed in USA.

A stamped self-add ressed envelope must accompany all submitted manuscripts and or artwork or photographs if
their return is desired should they be rejected. We disclaim any responsibility for the loss or damage of
manuscripts and/or artwork or photographs while in our possession or otherwise.



Computer
Digest



M. Harvey Gernsback,
editor-in-chief, emeritus



Larry Steckler, EHF, CET

publishers editor in chief
Art Kleiman, editorial director
Byron G. Wels, editor
Brian C. Fenton, managing editor
Carl Laron, associate editor
Robert A. Young, assistant editor
Ruby M. Yee, production director
Karen Tucker,

production advertising
Robert A. W. Lowndes,

production associate
Geoffrey. 5. Weil,

production assistant
Andre Duzant, technical illustrator
Jacqueline P. Cheeseboro

circulation director
Arline R. Fishman,

advertising director






Computer Digest
Gernsback Publications, Inc.
Executive offices
500-B Bi-County Blvd.,
Farmingdale, NY 11735
516-293-3000
President-. Larry Steckler
Vice President: Cathy Steckler

ADVERTISING SALES 516-293-3000

Larry Steckler
Publisher

NATIONAL SALES

Joe Shere

1507 Bonnie Doone Terrace

Corona Del Mar, CA 92625

714-760-8697



MAY 1986 — ComputerDigest 3



LETTERS

More Plus 4

I just acquired a Commodore
Plus 4 and can't seem to set any
information at all on the unit. Can
anybody out there help me?
— RK., Rowayton, CI

F.K., we've gotten a lot of mail
on this. It seems that somebody's
pushing these units at a low price
on TV We've done a bit of digging
around, and suggest that you write
to ETT Book Club, Department CD,
P.O. Box 240, Massapequa Park, NX
11762. Send 'em $6.50 plus $1.00
shipping and handling, and they'll
send you a book on programming
the Plus 4 and C-16.



Thank YOU T.J. We appreciate the
kind words.



Moving

I see from your last issue that
you've moved or are moving. Will this
have any effect on my
subscription? — S. L, Taos, N.M.

No, 5. L By the time you read these
words, the move will have been
accomplished. Since it's the nature of
a magazine to work ahead, we're well
backed-up with ready-to-go material,
so your issues will continue as though
nothing happened.



Valuable tool

I just wanted to write and say that I
count ComputerDigest Magazine as

one of my more valuable tools. I save
every issue and refer to them
constantly Thanks for the good job! —
T J., Oklahoma City OK.



Dilletante?

It seems that interest in
electronics comes in waves. First it
was hi-fi, then stereo, followed by
the CB craze. After that it was
computers, and as suddenly
interest shifted to satellite.
Magazines suddenly burst out to
cater to those interests, the



electronic shops stock up for
them, and as suddenly, they die
out. From where you sit, can you
tell me what's coming next?
— P.I, Princeton, NJ.

Wish I could, PJ. I'd be laying
out a new magazine right now! But
I don 't have a crystal ball either
Incidently, you can eliminate
computers from your list of "drop-
outs. " Because the computer has
such enormous practical value to
so many it isn't just a passing fad.
We're here to stay!

Help?

Can anybody help with a service
manual or schematic for a
Commodore SX-64? (Not a C-64). I'll
pay any reasonable fee for this
information. It's not available from
Commodore or Sams.- — R S., Boynton
Beach, FL.

if you can help, write to Paul
Schultz, 9535 tistow Terrace, Boynton
Beach, FL 33437.



COMPUTER PRODUCTS

For more details use the free information card inside the back cover



TOUCH SCREEN, is a 19-inch capaa-

tive touch screen, designed for OEM's
and systems integrators, The
MicroTouch Screen comes fabricated
in the standard spherical shape to fit
most 19-inch monitors, or in cylindrical
form to fit the line of 19-inch Sony
monitors. It more than doubles the
display area of the 13-inch screen,
providing better visibility greater visual
impact, and more touch area to ma-
nipulative data.

The MicroTouch Screen allows users
to interact with the computer intu-
itively by simply touching images on




CIRCLE 11 ON FREE INFORMATION CARD



the CRT screen. The screen operates by
automatically sensing the location of a
capacitive coupling when it is
touched by a finger or conductive
stylus. Constructed of solid glass with
a resistive coating bonded to its sur-
face, the screen is virtually impervious
to damage under normal conditions,
and will not distort the display image.
The MicroTouch Screen is priced at
$1395.00 for single units.— Micro-
touch Systems, Inc., 400 West
Cummings Park, Wobum, MA 01801.

TALKING MODEM, the Intelligent Talk-
ins Terminal, lets the user receive
modem-transmitted data verbally, just
as if he or she were listening to a
telegram on the phone. The user can
also receive information the ordinary
way: text-on-screen or printed. The
Intelligent Tdlking Terminal enunciates
data transmitted over phone lines —
even if transmitted at high baud
rates — and talks in clear, understand-
able speech.
With a talking modem, one can now



INTELLIGENT
TALKING
TERMINAL


A


tA




?~- — -







CIRCLE 12 ON FREE INFORMATION CARD

read and hear stock market quotes or
the latest business news. It can also be
tapped into a wide range of other
library data bases for educational,
research, and reference materials, fi-
nancial information, or news updates.
The Intelligent Tdlking Terminal has a
suggested retail price of $29.95. —
Welwyn Currah, 104 W Fourth Street,
Royal Oak, Ml 48067.



4 ComputerDigest — may 1966



SOFTWARE REVIEW



WORD FINDER— An Electronic Thesaurus.



■Depending on how it's used, a word can be dud or
exciting, or even take on a different meaning. And the
repeated use of words can turn even the most-exciting
thoughts into eyelid-closers.

Because of this, one of the most-important tools a
writer has, is a "thesaurus" which is a collection of
words arranged according to the ideas they are meant
to express. The author looks up the word he is
considering and the thesaurus suggests synonyms. For
example, if you want to avoid using the word "impair"
four times in a short sentence, a thesaurus will suggest
such words as "damage," "hurt," "harm," "injure," "mar,"
"prejudice," "tarnish," and perhaps a handful of others
if the thesaurus is sufficiently large.

Writers find it difficult to create text at lightning
speed on a word processor and then have to stop and
go through the pages of a thesaurus to locate a suitable
synonym. To meet the pace of the electronic age, the
electronic thesaurus was created which allows the user
to call up synonyms from the word processing
program. One of the best we've seen, and the easiest
to use, is WORD FINDER, designed for use with
WordStar, WordStar 2000, Multimate, Word Perfect,
pfsWRITE, Microsoft Word, and Easy Writer 2. We
tested the WordStar version because WordStar remains
the most-popular word processor.

WORD FINDER consists of a 30K control program
which is loaded into RAM prior to the word processor
and a 90,000 word dictionary that requires 157K of disk
storage. In a two-drive system, the thesaurus' dictionary
must be on the same disk as the word processor If
you're using WordStar either MailMerge or the spelling
checker can't be on the same disk. If you want direct
access of the thesaurus, a spelling checker and
MailMerge, the best arrangement is a hard disk or a
RAMdisk for the thesaurus' dictionary

The program responds to 9000 keywords which can
call up an average of ten synonyms each: It means you
may get anywhere from one to 50 synonyms for each
keyword.

WORD FINDER works at "lightning" speed whether
running from a hard disk, a floppy or a RAMdisk. To use
the thesaurus while composing a document, you mark



a word by placing the cursor on any character and
press a control key (which you can pre-program).
WORD FINDER creates a window on the screen with a
list of synonyms. If a suitable synonym is displayed, you
move the cursor in the window to the synonym, press
RETURN: The synonym substitutes for the marked word,
the window vanishes and the word processing display
is restored to full size. If there is no direct synonym the
window displays the alphabetically-closest spelling of
30 words and the selection process is repeated, only
this time it's for the words in the window, you can call
up the synonyms for any of the 30 words, and pressing
the RETURN key installs the selected synonym into the
word processing text. Even if the window doesn't
show the desired word or a close synonym there's a
good chance that something in the window will
suggest precisely what's needed. In this instance, you
simply type it into the word processing text.

Obviously, a 90,000 word thesaurus is not equal to a
printed version, but WORD FINDER is done well: We
had few omissions for commonly-used words. While
you might have to refer to a printed version, there is no
question that WORD FINDER ts a major enhancement for
a personal computer's word processor

Although WORD FINDER can be installed only
once — for your particular word processor — the
working program isn't protected and you can make as
many copies as you like; you simply cannot reinstall the
program for another word processor WORD FINDER
automatically determines whether your monitor is color
or monochrome from the computer's monitor adapter
bit and sets itself accordingly However, if you are
driving a monochrome monitor from a color adapter's
composite video output the program will assume
you're using a color monitor and key on the color
adapter, and the display will appear as garbage. If this
happens, run the DOS's MODE BW80 before you load
WORD FINDER.

WORD FINDER is priced at $129.95 for both POMS-
DOS and CP/M computers. It is available direct from
Writing Consultants, 11 Creek Bend Drive, Fairport, NY
14450. If you have any questions, phone them at 1(716)
377-01 30.^<D^



MAY 1986 — ComputerDigest 5



R-E Books Admart



CONFIDENTIAL
FREQUENCY LIST,
6th Edition



Frequency
List



|r> M.ftftr FEW";*



Latest available infor-
mation on the most
interesting communi-
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wave bands. Includes
SLB's, Phonetic Al-
phabet Stations,
Numbers Stations,
Military, Police, FBI,
Government Agencies and more. 304
pages, 6 x 9 inches. Get your own copy
for $15.95 plus $1 postage in USA. ELEC-
TRONIC TECHNOLOGY TODAY INC., PO
Box 240, Massapequa Park NY 11762-
0240.




CIRCLE 284 ON FREE INFORMATION CARD




CALL NOW
AND

RESERVE
YOUR SPACE



? 6 x rate $800.00 per each insertion.

? Reaches 229,044 readers.

? Fast reader service cycle.

? Short lead time for the placement of
ads.

Call 516-293-3000 to reserve space. Ask
for Ariine Fishman. Limited number of
pages available. Mail materials to;
Books Admart, RADIO-ELECTRONICS,
500-B Bi-County Blvd., Farmingdale, NY
11735.



Rates: Ads are 2Vr x 2%". One insertion $825, Six insertions $800 each. Twelve

insertions $775 each. Closing date same as regular rate card. Send order with

remittance to Books Admart, Radio Electronics Magazine, 500-B Bi-County Blvd.,

[Farmingdale, NY 11735. Direct telephone inquiries to Ariine Fishman, area

[ code-516-293-3000. Only 100% Book ads are accepted for this Admart



ELECTRONIC SCIENCE
PROJECTS



Electronic

S?ri*ncfl

Projects



\J\j w



Soft cover; 12 projects, each one with a
strong scientific flavor. Projects range
from a color-temperature meter to an os-
cilloscope with a solid-state display to an
infrared laser, $5.75 plus $1 postage in
USA. Electronic Technology Today Inc.,
PO Box 240, Massapequa Park, NY
11762-0240.



CIRCLE 284 ON FREE INFORMATION CARD



LINEAR IC EQUIVALENTS
& PIN CONNECTIONS



Linear IC

Equivalents
and Pin
Connection*




Shows equivalents & pin connections of a
popular user-oriented selection of Euro-
pean, American and Japanese liner IC.'s
320 pages, 8 x 10 inches. $13.50
postpaid in USA. ELECTRONIC TECH-
NOLOGY TODAY INC., P0 Box 240, Mas-
sapequa Park, New York 11762-0240.



CIRCLE 284 ON FREE INFORMATION CARD



25 SIMPLE AMATEUR
BAND ANTENNAS




umiiiour Band



^Y




Simple and inexpensive to build; yet per-
form well. Dipoles, beam, triangle and
even a mini-rhombic made from 4TV
masts and about 400 feet of wire. In-
cludes dimension tables to help you spot
an antenna on a particular frequency.
$5.00 plus $1 postage in USA. Electronic
Technology Inc. PO Box 240, Massape-
qua Park, NY 11762-0240.



32

ELECTRONIC

POWER SUPPLY

PROJECTS

Soft cover; 291 pages
of practical DC circuit
applications forawide
variety of hobby and
experimental pur-
poses! Circuits range
from the very simple
(like a half-wave sup-
ply) to more advanced
units (like a 12-volt in-
verter). $10.95 plus S1 postage in USA.
ELECTRONIC TECHNOLOGY TODAY
INC., P0 Box 240, Massapequa Park,
NY 11762-0240.







CIRCLE 284 ON FREE INFORMATION CARD



WHITE'S RADIO LOG




An up-to-date directory of North Amer-
ican AM, FM and TV stations including
special section on world-wide shortwave
stations. 136 pages, 5/a x TO inches,
soft cover. $4.95 plus 31 postage in USA.
ELECTRONIC TECHNOLOGY TODAY
INC., PO Box 240, Massapequa Park,
NY 11762-0240.



CIRCLE 284 ON FREE INFORMATION CARD



103 PROJECTS FOR

ELECTRONICS

EXPERIMENTERS



103

PROJECTS FOR

ELECTRONICS

EXPERMENTERS



Soft cover; 308 pages
of practical, proven
plans for the elec-
tronics hob-
byist... circuits, con-
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synthesizers, op-
toelectronics, power
supplies and more.
Written and designed
by Forrest M. Minis,
postage in USA. ELECTRONIC TECH
N0L0GY TODAY INC., PD Box 240, Mas-
sapequa Park, NY 11762-0240.




$11.50 plus $1



CIRCLE 284 ON FREE INFORMATION CARD



CIRCLE 284 ON FREE INFORMATION CARD





W/AUB ?W fi

?1MB




You push the middle key down,
and the signals go round and round,
whoa-ho-ho-ho, ho-ho.



Robert Grosblatt

■The Sinclair ZX-80 and ZX-81 got more people
hooked on computers than any machine ever made.
For under a hundred bucks you could connect it to a
iy power it up, and find out what computers were
about. If you were interested you moved to a bigger
machine. If not, it was worth it to satisfy your curiosity

Even though technology has increased, prices have
decreased, and the lowly Sinclair is no more, the fact
remains that it's still a powerful machine. Now that it's
available on the surplus market for under twenty bucks,
what was a good deal has become a bargain.

The bigsest drawback to the Sinclair is the
membrane keyboard. Not only is it a pain to use but,
unless you're gentle with it, it breaks. Replacing the
keyboard is a good idea but it seems ridiculous to
spend some $50 on a keyboard for a twenty dollar
computer Well, things are looking better.

When Texas Instruments dropped the T1-99/4A, a
huge inventory of keyboards were dumped on the
surplus market. Modifying them for use on the Sinclair
is easy...easier, in fact, than adapting some of the more
expensive keyboards. In order to understand what has
to be done, let's take a look at the Sinclair

The Sinclair

Both the Sinclair and the Tl use a simple matrix-type
keyboard. This means that each key returns a unique
row and column code every time the computer looks
at the keyboard to find out which key was pressed.
Unfortunately these keyboard codes have nothing to
do with standard ASCII. However, Tl's oddball
keycodes are so close to Sinclair's oddball codes that
it only requires minor keyboard surgery to make them
the same.



Sinclair


Keyboard Horizontal Grouping Showing




Connector Numbers


#8 1


2 3 4 5


6 7 8 9 #6


#7 a


WERT


Y U 1 P #4


#5 A


S D F G


H J K L ENT #2


#3 SHFT


Z X C V


B N M . SPC #1



Sinclair Keyboard Vertical Grouping Showing
Connector Numbers



#9


#10


#n


#72


#75


#13


#12


#11


#70 #5


1


2


3


4


5


6


1


8


9


Q


W


E


R


T


Y


U


1


P


A


S


D


F


G


H


J


K


L ENT


SHFT


Z


X


C


V


B


N


M


. SPC



Tl Keyboard Horizontal Grouping Showing
Connector Numbers



#9 LCK FCTN 12 3 4 5
#6 CNRL Q W E R T

#73 SHFT A S D F G

#5 ZXCVB



6 7 8 9 #14

Y U 1 P ENT #15

H J K L ; SPC #12

N M , . / = #11



Tl Keyboard Vertical Grouping Showing
Connector Numbers

#70 #4 #8 #3 #2 #7 #7 #7 #7 #2 #3 #8 #4
LCK FCTN 12 3 4 5 6 7 8 9

CTRL QWERTYU I OP ENT
SHFT ASDFGHJKL;SPC
ZXCVBNM, . / =

FIG. 1— COMPARING THE LAYOUTS of the two keyboards.
Both have eight horizontal sections but the Tl has two extra
vertical sections.



MAY 1986 — ComputerDigest 7



In Figure 1 you can compare the layout of the two
keyboards. The first thing you should notice is that
while both keyboards have eight horizontal sections,
the Tl has two extra vertical sections. One of them,
#10, is for 'Alpha Lock" and the other, #4, contains
most of the operator keys. Figure 2 shows you how
these section numbers relate to the connectors going
from the keyboard to the computer's motherboard.

There are a couple of ways to go about adapting the
Tl keyboard to the Sinclair The most elegant is to
design some circuitry that converts Tl code to Sinclair
code. Put the translation tables in an EPROM and the
circuit does everything for you. This lets you add
goodies like auto repeat, macros, and function keys.
After all, the Tl keyboard has seven extra keys to play
around with. The disadvantage is that you have to
design circuitry, build a board, and burn EPROMs.

The easiest way is to do a bit of cutting and pasting
to the Tl board to make it put out the codes the
Sinclair expects to see. Most of the extra keys will go to
waste but it's less work. Especially since the two
keyboards have really si mi liar arrangements to start
with. Figure 3 is a list of the changes that have to be
made to the Tl keyboard. There are fourteen keys that
have to be moved. The Alpha Lock" key a push on -
push off switch, can be isolated and put in parallel
with the "Shift" key to give a quick and dirty Shift lock.

Unfortunately, the rest of the Tl's extra keys won't do
anything at all. They can't be used for extra characters
because the ZX-81 won't recognize any additional
keycodes All you can do is put them in parallel with



Sinclair Keyboard Connectors Viewed from the
Back of the Keyboard



12 3 4 5 6 7 8



9 10 11 12 13



Vertical
Connectors



Horizontal
Connectors



Tl Keyboard Connectors Viewed from the Back
of the Keyboard

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15



Horizontal Connectors = 5, 6, 9, 11, 12, 13, 14, 15
Vertical Connectors = 1, 2, 3, 4, 7, 8, 10

FIG. 2— HOW THE SECTION NUMBERS relate to the con-
nectors from the keyboard to the computer's motherboard.



other keys to make the keyboard more convenient to
use. Once you've made these changes to the Tl
keyboard all that's left is making the connections to the
ZX-81 motherboard.

Turn the ZX-81 upside down and locate the five
screws that hold the case together Three of them are
located under the rubber feet as shown in Figure 4.
Once the case is open, lift out the mother board by
removing the two retaining screws, pull the two
keyboard connectors from their sockets and tape them
out of the way on the underside of the case. Solder 12-



Cut and Paste Guide for Adapting the Tl Keyboard at




the Sinclair


Key


Original Location


New Location


B


Horizontal #15


Horizontal #1)


SPC


Horizontal #12


Horizontal #11


SHFT


Horizontal #13


Horizontal #5


ENT


Horizontal #15


Horizontal #12


LOCK


Horizontal #9


Horizontal #11


Z


Vertical #8


Vertical #3


X


Vertical #3


Vertical #2


c


Vertical #2


Vertical #1


V


Vertical #1


Vertical #7


N


Vertical #7


Vertical #1


M


Vertical #1


Vertical #2


ENT


Vertical #4


Vertical #8


SPC


Vertical #4


Vertical #8


SHFT


Vertical #4


Vertical #8


LOCK


Vertical #10


Vertical #8



Tl Keyboard to ZX-81 Motherboard Connection Guide



T1


ZX-81


Keyboard


Motherboard


1


12


2


11


3


10


4


NOT USED


5


3


6


7


7


13


8


9


9


8


10


NOT USED


11


1


12


2


13


5


14


6


15


4



FIG. 3— A LIST OF CHANGES to be made in the Tl keyboard. A
total of fourteen keys have to be moved.



8 ComputerDigest — may 1986







Sinclair Keyboard Keycodes



FIG. 4 — TURN THE ZX-81 upside-down and you'll see the five
screws that hold the case together.

inch lengths of hookup wire to each of the thirteen
keyboard connectors on the bottom of the
motherboard. You can remove the original keyboard
connectors but it's easier to lap solder directly to the
motherboard. The same is true of the Tl keyboard.

As you can see from Figure 5, I used male and
female DB-25 connectors to connect the Tl keyboard to
the Sinclair motherboard but you can connect them
directly together. Since the ZX-81 motherboard is
smaller than the keyboard, you can get rid of the case
and put the whole thing together in a small utility case.
If so, use an aluminum case and connect the case to
the housing around the RF modulator The Sinclair has a
problem with RF and you'll have trouble with the video
if you use a plastic box.

I can't show you exactly how to do the surgery on
the keyboard. Tl used several manufacturers to make
the boards and though all the keyboards are
functionally the same, the traces are different from
manufacturer to manufacturer: As long as you identify
the switches on the printed circuit board you should
have no trouble altering it to use on the Sinclair

When you finish, don't throw away the old Sinclair
keyboard. You can cut out the key tops with a hobby
knife and glue them to the tops of the keys on the Tl
keyboard, A new keyboard is nicer if the keys are
properly labeled.




Key Location Pressed


Keycode


Register


None


FF


L


Horizontal #1


7F


L


Horizontal #2


BF


L


Horizontal #3


FE


L


Horizontal #4


DF


L


Horizontal #5


FD


L


Horizontal #6


EF


L


Horizontal #7


FB


L


Horizontal #8


F7


L


None


FF


H


Vertical #9


FD


H


Vertical #10


FB


H


Vertical #11


F7


H


Vertical #12


H




Vertical #13


DF


H



FIG. 5— MALE AND FEMALE DB-25 connectors connect the Tl
keyboard to the Sinclair motherboard.



If the SHIFT key is pressed with another key bit is reset
to in the H register so that FF = FE, FD = FC, F7 = FB, etc.

FIG. 6— HERE ARE THE CODES put out by the Sinclair key-
board. This will be of great help if you're building translation
circuitry.

Translation circuitry

If you're set on building translation circuitry you'll
find Figure 6 helpful. I've listed the codes put out by
the Sinclair keyboard. The keyboard scannins routine in
the Sinclair ROM (located at 022B hex) returns with the
keycode in the Z-80's HL register. The key's row
(horizontal) location is stored in L and the column
(vertical) location is stored in H. Once the computer
has the complete keycode, it uses a routine located at
07 BD hex to translate the code into the character it
represents. The lookup table is stored from 007E to
O0CB hex.

Building circuitry to do the job means bringing
power and ground out from the motherboard. Since
the data bus has to be 13 bits wide, you'll have to think
about the 8 bit limitation of the EPROM. There are two
ways of handling the problem. Vbu can use two
locations in the EPROM to store each keycode and let
your circuit clock the data out in order or use two
EPROMs to widen the bus to 16 bits. This last approach
is easier and even though it means burning two
EPROMs it will cut the circuitry needed down to a
much more managable size.

The Sinclair is a great first computer and a good
choice for a dedicated controller Once you get your
software straight, you can burn the program into an
EPROM and replace the ZX-81's 2k RAM chip with the
EPROM. Although I've been skimpy on the details of
designing the EPROM circuitry needed to do a nifty
keyboard adaptation, if there's enough interest I can
deal with it much more thoroughly in a separate
article.-^CD^



MAY1986 — Comp u te r Di g est 9



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10 ComputerDigest — MAY1986



REMOTE POWER
CONTROLLER
FOR YOUR
COMMODORE-64

Couple a wireless remote and your
computer Instant automation!

Chandler Sowden



■One of the useful things a home computer can do is
control things around the house. Unfortunately this
usually involves stringing control wires from the
computer to the device being controlled.

Enter the home wireless remote control system, as
manufactured and sold by BSR and Radio Shack. With
this system, lights and appliances can be controlled
(manually) from a central location without wires.

How it works



The wireless remote modules respond to a pulse



PULSES

FROM

COMPUTER



-TU-LTL.



TO AC

TOWER



%'



TIME

OUT



-TLTLTL



DSC



OPTICAL
ISOLATORS



WAVE
SHAPING




TIMING SIGNAL
TO COMPUTER

FIG. 1— BLOCK DIAGRAM reveals simplicity of the circuit.
Opto- isolators keep AC out of the computer.

coded 125KHz signal placed on the AC power line.
The pulses occur in groups of three and are
synchronized to the power line. As shown in Figure 1,
the device consists of a 60 Hz wave shaping circuit, an



PULSE




FIG. 2 — SCHEMATIC DIAGRAM is simptified because circuit uses computer software to provide
many of the necessary functions. Refer to text for in-depth explanation.



MAY 1986 — ComputerDigest 11




FIG. 3— HERE'S THE FOIL PAT-
TERN for those of our readers who
desire to do their own circuit-board
etching.



FIG. 4— ...AND WHEN YOU'VE GOT
THE BOARD etched, here's where
alt the parts go.



?" n




hi ■




oscillator, a time-out circuit, and optical isolators to
keep AC line power out of the computer Machine
language software in the computer first looks at the 60
Hz square wave from the device. This input changes at
each zero crossing of the AC power line voltage. The
computer then either outputs a group of three pulses
or waits until the next zero crossing, depending on the
code to be transmitted. These pulse groups go through
the optical isolator and time-out circuit and are applied
to the oscillator, which places corresponding bursts of
125 KHz on the power line. The grouping of pulses is
controlled by the machine language software, and
depends on the house code, unit code, etc., to be
transmitted. The time-out circuit is to prevent a
software hang-up from leaving the oscillator on. If the
pulse output from the computer stays high for 2
seconds or more, the oscillator is switched off until the
output returns to zero.

The circuit

The circuit is shown in Figure 2. When the computer
sends a high logic level signal on the PULSE input,
transistor Q1 turns on, which turns on optical isolator
IC2 and transistor Q4. This triggers the monostable side
of ICI, whose output then releases the RESET input (pin
10) of the astable side, allowing it to oscillate. Its 125
KHz output is amplified by Q5 and then applied to the
AC power line through capacitor C4, When the PULSE



input goes low, IC2 turns off and the monostable is
reset through resistor R6, thus shutting off the 125 KHz
output. If the PULSE input remains high for some reason,
the monostable times out after about 2 seconds and
shuts off the oscillator: Returning the PULSE input to low
then restores normal operation.

Assembly

The power controller can be easily assembled using
point-to-point wiring or a printed circuit board. A foil
layout is shown in Figure 3, and component placement
in Figure 4. Note that the optical isolators are mounted

FIG. 7— PROGRAM LISTING.

1 REM ESR PDWER CONTROLLER PROGRAM

2 REM FOR COMMODORE 64

3 REM WRITTEN BY G.C. 5DWDEN 6/14/B5
10 LET P=PEEK (56577 >

20 FOR 1=1 TO 20

30 IF PEEK (565771 - .-P THEN GO TD 100

40 NEXT I

50 PRINT "POWER CONTROLLER IS NOT PLUGGED IN"

60 END

100 POKE 56579. 1

102 GOSUB 109

104 BO TO 600

10? RESTORE

HO FOR A=49152 TO 49336

120 READ D

130 POKE A.D

140 NEXT A

142 RETURN

145 REM BSR

150 DATA 169,2,141,42,192



12 ComputerDigest — may 1986




160 DATA 32,47,192,173,43,192

170 DATA 141,44,172,32,68,192

180 DATA 173,45,192,208,3,32,74,172

190 DATA 173,46,172,141,44,172,32,68

200 DATA 192,206,42,192,208,222,96,0,0

210 DATA 0,105,0,0,171

220 REM SC

230 DATA 32,74,172,167,3

240 DATA 141,67,192,32,120,192

250 DATA 206,67, 172, 209, 24B, 32, 74, 172

260 DATA 96, O

270 REM BITS

280 DATA 169,8,141,93,192,14,44,192

290 DATA 144,6,32,120,172,76,87,172

3O0 DATA 32,94,192,206,93,192,208,237

310 DATA 96,0

320 REM TZ

330 DATA 169,0,141,117,172,206,117,172

340 DATA 208,251

350 DATA 173,1,221,141,117,172

360 DATA 173,1,221,205,119,192,240,248

370 DATA 96,0

3 BO REM Tl

390 DATA 169.3,141,160,192,173,161,172

400 DATA 7,1.141,1,221,162,186,202

410 DATA 208,253,173,161,192,141,1,221

420 DATA 167,183,141,162,192

430 DATA 206,162,172,208,251

440 DATA 206,160,192,208,222,96,0,0,0

450 REM UNIT CODES

460 DATA 105,169,89,153,86,150,102,166

470 DATA 106, 170,90, 154,55, 149, 101,165

4S0 DATA 179,181,173,171,205,203

600 LET N=100

610 DIM T(N>,U(N>,FtN) ,S*(16)

620 FOR 1=1 TO N

630 READ TtI),U!I),F(I)

635 IF Tfl)>2357 THEN 80 TO 1000

640 NEXT I

650 DATA 1201, 1, 1

651 DATA 1202,1,2

999 DATA 9779,0,0

1000 LET C*="A"

1010 PRINT "TIMEIHHMM) "

102O INPUT T*

1030 LET TI*=T*+"00"

104O LET T*=LEFT*(TI*,4?

1O60 LET HS=LEFT*(T*,2>

1070 LET M*=RIGHT*(T*,2)

1090 LET T1=VAL(T*>

1100 FOR 1=1 TO N

1105 IF T(I)>2357 THEN GO TO 1160

1110 IF T(IK>T1 THEN GO TO 1150

1120 LET U1=U(I)

1130 LET F1=F(I >

1140 GOBUB BOOO

11SO NEXT I

1160 GOBUB 7000

1170 LET TO*=LEFT*(TI*,4>

1180 IF PEEK (197)064 THEN 60 TO 1220

1190 IF T*=TO* THEN GO TO 1170

1200 LET T*=TO*

1210 GO TO 1O60

1220 IF PEEK (197)064 THEN GO TO 1220

1230 INPUT D*

1240 INPUT "TYPE DEVICE NUMBER: ";U1

1250 IF U1=0 THEN END

1260 INPUT "FUNCTION? (TYPE 1 FDR ON, 2 FDR DFF)";F1

1270 GOSUB BOOO

1280 GO TO 1160

7000 PRINT " tCLR) "

7010 PRINT H*; ": ";M?

7020 PRINT

703O PRINT "DEVICE NUMBER AND STATUS:"

7040 PRINT

7050 FQR K=l TO 16

7060 PRINT S?(K) ,

7065 NEXT K

7070 PRINT

70S0 PRINT "PRESS RETURN FOR MANUAL CONTROL"

7070 RETURN

BOOO LET Sl*=" OFF"

803O IF Fl=l THEN LET Sl*=" ON "

8040 LET S*(U1)=STR*(U1)+Si?

8050 GOBUB 9000

8060 RETURN

7000 GOBUB 109

9002 POKE 49195, PEEK ( 47250+ASC IC*> )

900B POKE 47198, PEEK (493 14+U1)

9010 POKE 49197,1

9020 SYS 49152

9030 FOR J=l TO 10



7031 NEXT J

9032 IF Fl<5 THEN GO TO 90EO

9034 LET F2=2* (F1-10Q*INT(F1/100) )

7036 LET F1=INT(F1/100>

9040 POKE 47153, F2

9050 POKE 49198, PEEK (49330+F1)

9060 POKE 47197, O

9070 SYS 49152

9075 POKE 47153,2

70BO PRINT U1.F1

9082 FOR J=l TO 200

90B4 NEXT J

9090 RETURN



TOP OF CONNECTOR



PIN1




pin:

PINE



GND "SYNC"



FIG. 5— WIRING FOR THE CONNECTOR is shown above.
Provide good mechanical connections for all leads and then
carefully solder.



LINE
CORD



7/32"



■1/4"

T



7/1B"



-7/8"-



7/32"



FIG. 6— DIMENSIONS ARE PROVIDED here for openings in
the connector. See text for additional explanation.



facing opposite directions. You'll have to cut openings
for the AC cord and the computer card-edge
connector The connector mounts on the side of the
box, and it than plugs into the Commodore User Port.

After the components are in place, install the power
cord. Solder hookup wire to the card-edge connector,
as shown in figure 5. Cut a rectangular opening in the




FIG. 8— THE CIRCUIT BOARD completely wired, ready for

installation in the box.



MAY 1986 — ComputerDigest 13




FIG. 9— POWER CONTROLLER installed in the box with the
connector attached. Note that only four of the 24 pins are
used.




FIG. 11— THIS ILLUSTRATES the power controller connected
to the computer. Be sure the connector location is such that
the box does not cover the opening for the cassette interface.



plastic box for the card-edge connector, as shown in
Figure 6.

Using a volt-ohmmeter, measure the resistance
between a blade on the power plug and the
connector contacts. There should be no continuity
between the power plug and any contact on the
connector Next, plug the unit into a wall outlet and
CAREFULLY measure the DC voltage at the output of the
bridge rectifier. It should be about 8 volts. Be careful,
because most of the components have power line
voltage on them.

The software

Type the software in from the listing given in Figure 7.
Double check the listing, especially the DATA
statements. Save the program on tape or disk before
you run the program.

The program is designed as a clock-time controller,
but it also allows manual control of the remote
modules from the computer keyboard. The program
allows up to 100 on or off operations in a day, but this
could be changed by changing line 600. The desired
on/off times are in DATA statements is: (line number)
DATA time, unit, code where "code" is a 1 for on, 2 for
off. In the program, line 650 means 'At 12:01 (24 hour
time), turn unit 1, ON (code D," while line 651 says 'At
12:02, turn unit 1, OFF (code 2)."

The "house code" for the power controller is set at
line 1000. Sixteen different house codes are pro/ided,




FIG. 10— POWER CONTROLLER plugs into the user port at
the rear of the cabinet.



in case your neighbor uses a similar system.

Take a remote module, set it to House Code 'A" and
unit code "1." Plug it in and plug a lamp into it. Run the
program. It will then ask for the time. Type in the time in
4-digit, 24-hour format, then return. The program will
clear the screen, print a heading, then a line which asks
you to "press return for manual control." Press RETURN.
It will say "type device number,-" type 1 (and return); it

PARTS LIST
Semiconductors

BR1 — 1 ampere, 50V. bridge rectifier

IC1— LM556 dual timer

IC2, IC3— TIL111 {or similar) optical isolator

Q1-Q4— 2N3904 or similar transistor

Q5— TIP31 transistor

Resistors

(All resistors Viwatt unless otherwise indicated)

R1— 10,000-ohm

R2 — 4700-ohm

R3— 150-ohm

R4 — 470-ohm

R5— 15,000-ohm

R6-R8, R10— 1000-ohm

R9 — 1-megohm

R11— 6800-ohm

R12 — 10,000-ohm Vs watt potentiometer

R13— 220-ohm

R14— 100,000-ohm

R15— 10-ohm, 2 watts

Capacitors

(All capacitors at least 16V.)

C1— .0047 p. F,

C2— 3.3u.R C3— 470pF

C4— .22u.F.

C5— 1000H-E

Miscellaneous parts and equipment

F1 — Va a. fuse (see text)

J1 — Card-edge connector, Texas Instruments No.

H411121-12 (available from Digi-Key Corp., P. O. Box

577, Thief River Falls, MN 56701-9988)
T1— 6.3V 300mA transformer
Line cord, box, etc,

will ask "Function? (Type 1 for on, 2 for off)." Type 1
(and return). The lamp should turn on. If it doesn't, try
checking the house and unit codes, then check the
program for typos. If that doesn't help, then try
tweaking potentiometer R12. -^CD^



14 ComputerDigest — MAY 1986



COMPUTERIZED
POWER SUPPLY

COMPONENT
SELECTION



Let your computer choose
your power-supply components.



Jack Cunkelman

■As critical as a power supply may be, it seems to be
the last thing to be considered. Only after a project is
working, using the bench supply do we think about
the power supply and how we are going to fit it into
the enclosure. This is where this program comes into
play It will make component selection faster and easier

A power supply can consist of a battery or a
transformer/rectifier assembly to power it from 120 volt
AC sources. The linear type of power supply seems to
be the most popular transformer/rectifier combination
and that is what we will deal with here.

There are only a few ways to obtain DC power from
AC sources using linear power supplys. One of the
following three circuits are used by most
experimenters: full wave bridge, full wave-center
tapped, and full wave bridge -center tapped. We will
limit ourselves to these three circuits.

Once the program is running there are two options
available, output to the screen or output to a printer.
The printer output will generate a list of component
rating values for various power supply voltages and
configurations.

The screen option treats the transformer as the
variable element. Plugging in the values from those
transformers in your "junk box" will enable you to
quickly determine if they can be used or not. The
screen display also deals with current ratings. A entry
when a question is asked will return you to the menu.
A entry on the menu will stop the program.

All ratings are conservative for cool running, reliable
operation. If you cannot find components with the
exact rating, always step up to the next highest rated
component available.





FULL WAVE


BR I DOE






CAPACITOR


INPUT FILTER


TRANSFORMER


DC


DIODE


CAPACITOR


VOLTASE<RMS>


VOLTS


PIV


VOLTAGE


3


A


12


7


6


B


16


10


7


9


18


11


B


10


20


13


9


12


24


15


10


13


26


16


11


14


28


IB


12


16


32


20


13


17


34


22


14


IS


36


23


IS


20


40


26


16


21


42


27


17


22


44


28


IB


24


48


31


19


25


30


32


20


26


52


33


21


28


56


36


22


29


58


37


23


30


60


39


24


32


64


41


29


33


66


42


26


34


68


44


27


36


72


46


28


37


74


48


29


3B


76


49


30


40


80


32


31


41


82


53


32


43


86


35


33


44


BS


57


34


45


90


58


35


47


94


61


36


48


96


62


37


49


9B


63


39


51


102


66


39


32


104


67


40


53


106


68


41


55


110


71


42


56


112


72


43


57


114


74


44


59


11B


76


43


60


120


78


46


61


122


79


47


63


126


81


48


64


12S


83


49


65


130


84


50


67


134


B7


= 1


68


136


SB


52


69


13B


B9


53


71


142


92


54


72


144


93


53


73


146


94



POWER SUPPLY SPECIFICATION PR



10 CLS

20 REM

OGRAM

30 REM BY JACK CUNKELMAN

40 REM JUNE 19B3

50 INPUT "DO YOU WANT SCREEN DISPLAY

(S) OR PRINTER OUTPUT CP)"jD$
60 IF D*-"S" THEN BO
IF D*-"P" THEN 500
PRINT "INPUT ERROR" i GOTO 50
CLS
PR I NT "POWER SUPPLY TYPE"

FULL WAVE BRIDGE (1) "
FULL WAVE CENTER TAP (



70
75

BO
B5

90 PRINT"
100 PRINT"
2) "

110 PRINT"
R TAP <3> "
120 PRINT"
FILTERING'
130 INPUT"
TO QUIT" j T
135 IF T-0 THEN END
140 ON T GOTO 1000,2000,3000
150 GOTO BO
500 CLS
510 PRINT "THE PRINTER OPTION



FULL WAVE BRIDGE CENTE



ALL USING CAPACITOR INPUT



SELECT TYPE 1



3 OR



PRINTS



MAY 19B6 — ComputerDigest 15



A TABLE OF VALUES FOR VARIOUS
TRANSFORMERS"
520 PRINT "TYPE OF CIRCUITi "
330 PRINT" FULL WAVE BRIDGE (1)"
340 PRINT" FULL WAVE CENTER TAP (

550 PRINT" FULL WAVE BRIDGE CENTE

R TAP (3)"

560 PRINT" ALL USING CAPACITOR INPUT

FILTERING"
570 INPUT" SELECT TYPE 1,2,3 DR

TO QUIT" j T
580 IF T-0 THEN END
590 ON T GOTO 1500,2500,3500
1000 CLS

1010 PRINT"FULL WAVE BRIDGE , CAPACI
TOR INPUT FILTER"

1020 INPUT "TRANSFORMER RMS VOLTAGE")
V

1025 IF V-0 THEN SO

1030 INPUT "TRANSFORMER CURRENT RAT IN
G CAMPS) "iC

1040 RV-INT((V*.95*1.414)+.04)
1050 DV=INT(2*RV)
1060 CV?INTU.3*RV)
1070 OC - INT(C/1.8*10)
1080 GOSUB 5000

1090 PRINT V|TAB(21)RV(TAB(31)DViTAB
(41)CV|TAB<52)0C/10
1100 GOTO 1010
1500 CLS

1510 INPUT"MINIMUM TRANSFORMER VOLTA
GE"|M

1522 T*-"FULL WAVE BRIDGE"
1524 GOSUB 6000
1530 FOR V ■ M TO M+50
1340 RV-INT((V*.95*1.414)+.04>
1550 DV-INT(2*RV)
1560 CV-INT(1.3*RV>

15B0 LPRINT TAB (8) V; TAB (20) RV) TAB (31
>DV(TAB(41)CV
1590 NEXT V
1600 GOTO 500
2000 CLS
2010 PRINT"FULL WAVE CENTER TAPPED ,

CAPACITOR INPUT FILTER"
2020 INPUT "TRANSFORMER RMS VOLTAGE (
ENTIRE SECONDARY) "| V
2025 IF V-0 THEN 80

2030 INPUT "TRANSFORMER CURRENT RAT IN
G (AMPS)"*C

2040 RV-INTC (V*. 95*1. 414)+. 04)/2
2050 DV-INT(4*RV)
2060 CV-INT(1.3*RV)
2070 DV-INT(4*RV>
2075 0C-INT(C/1.2*10)
2080 GOSUB 5000

2090 PRINT VjTAB(2i)RVjTAB(31)DV|TAB
(41)CV f TAB(52)0C/10
2110 GOTO 2010
2500 CLS

2510 INPUT "MINIMUN TRANSFORMER VOLTA
GE (ENTIRE SECONDARY) " j M
2320 T*?"FULL WAVE CENTER TAP"



2524 GOSUB 6000

2530 FOR V - M TO M+50

2540 RV-INTC(V*. 93*1. 414)+. 04J/2

2550 DV-INT(4*RV)

2560 CV-INT(1.3*RV)

2580 LPRINT TAB (8) Vi TAB (20) RV) TAB (31

)DViTAB(41)CV

2590 NEXT V

2600 GOTO 500

3000 CLS

3010 PRINT "FULL WAVE BRIDGE CENTER

TAP, CAPACITOR INPUT FILTER"

3020 INPUT "TRANSFORMER RMS VOLTAGE (

ENTIRE SECONDARY) "|V

3023 IF V-0 THEN 80

3030 INPUT "TRANSFORMER CURRENT RATI

NG (AMPS)")C

3040 RV -INT( tV*. 95*1. 414)+. 04) /2

3050 DV - INT(4*RV)

3060 CV -INT(1.3*RV)

3070 OC -INT( (C/1.8)/2*10)

3080 GOSUB 3000

3090 PRINTVjTAB(lS) "+/-"RVj TAB (31 ) DV

jTAB(41)CV[TAB(49) "+/-"0C/10

3100 GOTO 3010

3500 CLS

3510 INPUT"MINIMUM TRANSFORMER VOLTA

BE (ENTIRE SECONDARY) " j M

3520 T*-"FULL WAVE BRIDGE CENTER TAP

II

3525 GOSUB 6000

3530 FOR V - M TO M+30

3540 RV - INT< (V*. 95*1. 414)+. 04)/2

3550 DV - INT(4*RV)

3560 CV - INT(1.3*RV)

3380 LPRINT TAB (8) Vj TAB ( 19) "+/-"RVj T

AB(31)DV[TAB(41)CV

3590 NEXT V

3600 GOTO 500

3000 PR I NT " TRANSFORMER " ) TAB < 20 ) " DC

"| TAB (30) "DIODE" (TAB (40) "CAPACITOR" |

TAB (32) " DC "

5010 PR I NT " VOLTAGE ( RMS > " ) TAB ( 20 ) " VOL

TS" | TAB (30)" PIV "i TAB (40) "VOLTAGE"p

TAB (51) "CURRENT (AMPS) "

5020 RETURN

6000 LPRINT1LPRINT1LPRINT

6005 LPRINT TAB (20) T*

6010 LPRINT TAB (20) "CAPACITOR INPUT

FILTER"
6015 LPRINT

6020 LPRINTTAB(S) "TRANSFORMER" 1 TAB (
20)" DC "j TAB (30) "DIODE"TAB (40) "CAPA
CI TOR"

6030 LPRINTTAB (5) "VOLTAGE (RMS) " ) TAB
(20) "VOLTS" j TAB (30)" PIV " ( TAB(40)"V
OLTAGE"
6035 LPRINT
6040 RETURN

The biggest variable seems to be the transformer and
how it is rated. I have always been within 10% of the
desired output value using the transformer's published

ratings.^O^



16 ComputerOigest — MAY 1986



cuit of that tube, A dynamic speak-
er probably gave the best audio
output.

Next comes the 240, a high-mu
(high-amplification) tube func-
tioning as the first audio stage. The
200A is a sensitive detector, and
the 222 is a screen-grid RF ampli-
fier. The tuning coi! is connected
directly to the grid cap of that
tube, and the plate circuit has a
special tuned circuit to increase
efficiency. There was also a dial
lamp across the filament circuit,
and a small switch on the tuning
capacitor to cut out the larger sec-
tion when tuning a high-frequency
(shortwave) signal.

That's one of the early Thrill
Boxes, but there were half a dozen
variations sold in different config-
urations. If a Thrill Box was pur-
chased pre-assembled, it included
a certificate guaranteeing that it
would bring in foreign stations.
Unassembled, it cost about $30,
and that included a metal cabinet.
Of course, early kits seldom in-
cluded tubes or an output device
(headphones or speaker), so the
inclusion of the metal cabinet was
a plus. By following the enclosed



instructions, the hobbyist of that
era could have the receiver as-
sembled and operating in about
two hours.

As the 1930's wore on, interest in
shortwave listening increased.
Around 1940, most home radios
had shortwave listening bands,
and band-switching had most re-
placed piug-in coils. What were
people listening to on all those ra-
dios?

Besides the hams, anyone who
needed instantaneous communi-
cations was on the shortwave
bands: ship captains, airplane pi-
lots, and police, to name a few.
Even the regular broadcast stations
transmitted on the shortwave
bands. One well-known broadcast
(by KDKA) was received by the
Byrd Expedition in 1929. It was sent
via shortwaves a distance greater
than 20,000 miles to Little America,
Antarctica. It was even possible to
pick up the audio portion of some
early TV transmissions. An an-
nouncer would interrupt occa-
sionally to explain what was going
on for those who were receiving
only the audio portion of the
broadcast.



Many governments started
transmitting on the shortwave
bands. The U. S. led the way with
over a dozen stations. And, unlike
many foreign countries, the U. S.
continually encouraged the
growth of Amateur Radio.

One thing that fascinated many
SWL's was the reception of Morse
code. Code could be received on
all bands, including the regular
broadcast band. Many broadcasts
were worthwhile copying for any-
one who was able to, and many
listeners who never became hams
were nevertheless expert at receiv-
ing code. Learning code was itself
a hobby. A code practice oscillator
(CPO) could be built from plans or
kits; pre-assembled units could
also be purchased.

Winding up

That's about all for now; next
month we'll discuss the Grunow
table model Type 5 with the tele-
dial, an automatic tuner that re-
sembles a telephone dial.

I hope to present the much im-
proved and expanded tube sub-
stitution chart soon. Thanks to all
who sent information. R-E




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>

-<



8

00



87



to
o

z
o
tr

H

o

_J



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<

68



designer's

Notebook



Schmitt triggers

ONE OF THE MAIN ADVANTAGES DIGITAL

has over analog electronics is the
ease with which signals can be
processed. After you've captured a
signal, you can do just about any-
thing you want with it. But it's
often a problem in digital (and in
analog) circuits to capture the sig-
nal in the first place.

The nice, logical circuit ele-
ments on the PC board want nice,
clean input signals. And a clean
input signal can be hard to come
by. Often a signal from the "real
world" must be conditioned be-
fore it can be handled by the elec-
tronics on your board. If the signal
is dirty, it's a safe bet that even the
world's best-designed circuit will
take one look, turn up its elec-
tronic nose, and refuse to deal
with it.

Probably the best, and simplest,
way to condition a signal is to use a
Schmitt trigger. All logic families
(TTL, LSTTL, CMOS, HCMOS,
etc.) have a collection of SchmiU
trigger IC's in several different gate
configurations. In Table 1 we list
several popular, off-the-shelf de-
vices. They're very easy to use, but
sometimes you don't have room
for another IC on a PC board, or



TABLE 1 —


SCHMITT TRIGGERS


IC


Type


Description


4093


CMOS


Quad 2-lnput NAND Gate


4584


CMOS


Hex Inverter


40106


CMOS


Hex Inverter


74C14


CMOS


Hex Inverter


7413


TTL


Quad 2-lnput NAND Gate


7414


TTL


Hex Inverter



cost considerations prevent you
from adding another IC, and so
on. So what you can do is build
your own Schmitt trigger using an



unused gate (and there's almost al-
ways one of those on a board).

Rolling your own

The circuit shown in Fig. 1 illus-




FIG. i



trates one way of converting a
standard non-inverting gate into a
Schmitt trigger. To understand
how it works, assume that we're
working with a CMOS gate, and
that its input (and its output) are
both low. What happens when we
bring the input high? If R1 weren't
connected to the input, the gate
would change state at Vi V cc , the
normal CMOS trip point.

However, with the resistors con-
nected, as the input begins to go
positive, the output of the gate re-
mains low. The resistors function
as a voltage divider that keeps the
voltage at the gate's input lower
than the actual input voltage. The
inverter will only change state
when the voltage at its input is
equal to half the supply voltage.
The two resistors make that trip
voltage greater than half the sup-
ply voltage.

When the gate finally changes
state, its output goes high, and
that output voltage will be higher
than the gate's input voltage.
When that happens, the voltage
divider helps pull the gate's input
high. So, if you think for a mo-




ROBERT CROSSBLATT

CIRCUITS EDITOR

ment, you'll realize that what
we've just described are the two
basic characteristics of a Schmitt
trigger — hysteresis and snap ac-
tion.

The same sort of dynamics occur
when the circuit goes the other
way. The circuit's trip point will be
less than Vi V cc by the amount of
hysteresis generated by the re-
sistors.

One advantage of designing
your own Schmitt trigger is that
you can play around with the val-
ues of the resistors and thereby
create a Schmitt trigger with just as
much hysteresis as you want. The
range of hysteresis, H, you get is
controlled by the supply voltage as
well as by the values of the re-
sistors:

H = (R1/R2)V CC

There are limits to the values the
resistors can have. You'll get no
Schmitt-trigger action at all if Rl's
value is very small compared with
R2's value, or if the resistors are
inadvertently switched. A sensible
limit for the values of the resistors
is about 200K for R2, and a max-
imum R1:R2 ratio of 5:1.

Since the circuit is so easy to rig
up, the best approach to finding
the right resistor values for a par-
ticular application is probably the
empirical one. Breadboard the cir-
cuit and then experiment with val-
ues for the two resistors. Just keep
those values within the limits just
mentioned. You could also create
a chart of the amount of hysteresis
produced by different combina-
tions of resistors. Keep it handy so
you can use it to build a custom
Schmitt trigger whenever the
need arises. R-E



State Of
Solid State



New op-amps

THE OP-AMP IS STILL ONE OF THE MOST

widely used linear IC's. The OP-41
op-amp from PMI (Precision
Monolithics, Inc., P.O. Box 58020,
Santa Clara, CA 95052) is a new
device that features a cascode FET-
input stage that has a CMRR (Com-
mon-Mode Rejection Ratio) of
greater than 100 dB. The OP-41 also
has improved linearity, and sta-
bilized bias current with changing
common-mode voltage.

The OP-41 consumes only 750
uA and it has a power-supply rejec-
tion ratio of 25 n-V/V. Those factors
make the OP-41 ideal for use in
battery-powered systems. Slew
rate is symmetrical, and, despite
the device's low current drain, is a
respectable 1.3 V/jj,s. Offset volt-
age has been reduced to less than
500 (jiV so external nulling is un-
necessary in many applications.

Other features include a max-
imum bias current of five pA, and a



guaranteed gain of 1 million into a
2K load. Linearity is good in both
high- and low-gain configurations.
As a voltage follower, the CMRR
effects dominate linearity, and, in
high-gain service, open-loop gain
dominates linearity.

Further, the OP-41 recovers
rapidly from signal overload. Fol-
lowing saturation at the positive
supply, the output recovers in only
6 (jls, and recovery from a negative
overdrive takes only 100 ns.

The superior performance
characteristics of the OP-41 make it
an excellent output amplifier for a
CMOS DAC (Digital-to-Analog
Converter). The OP-41 's low, stable
bias current would make it an ex-
cellent choice as a photodiode
amplifier in medical applications.
At unity gain, the output can drive
250 pF without oscillating.

The OP-41's superior charac-
teristics and a pin-out that is iden-



02
LM113



'?-



Ql-a
1/2MAT-B2EH



RI2 *?V
j R4



-NW






R5
2K 2K



INPUTO-



C1 "-f C2
ICQpF -± 2pF



,,Q3
2N2222




IpA

SI

RANGE



IDpA



lOOpA
1/<A



IQliA



R6
5110

1%
>R7

^sun

T 154

R8

5110

IK
?-R9
^?5110

1%

R10

5HO

1%



ai-b

Ml MAT-OZEH



1 OD.uA



> R11

:*5tio

'1?




FIG. 1



ROBERT F. SCOTT,

SEMICONDUCTOR EDITOR

tical to the industry-standard 741
make it simple for the designer to
up-grade an existing low-power
bipolar/JFET design.

An 11-page data sheet contains
performance curves for various
characteristics including bias cur-
rent vs. temperature, bias current
vs. common-mode voltage, supply
current vs. supply voltage, and
power-supply rejection vs. fre-
quency. Also included in the data
sheet are circuits for testing and
measuring performance charac-
teristics.

In addition, several applications
diagrams, including a high-Q
notch filter, a current-to-voltage
converter, and an amplifier for
piezoelectric transducers, are in-
cluded. But perhaps the most in-
teresting and useful application is
the low-current ammeter shown
here in Fig. 1. The circuit can mea-
sure current as low as a few pA and
as high as 100 u.A in six switch
ranges.

Unlike many low-current am-
meters, the one shown here does
not require high-value precision
resistors. As you can see, the desir-
ed range is selected from a tap on a
voltage divider made up of six 1%
(or better) 511-ohm resistors. The
ammeter's accuracy is 1% or better
over most of its range; accuracy
depends on the decade resistors
(R6-R11) and on the OP-41 's input
bias current.

Any good ammeter should
cause very little voltage drop
across its input terminals. The volt-
age drop across the input of the
OP-41 is less than 500 \lV, so that s
makes it effective as a low-current <
metering device. g

The circuit works as follows. §



89



Communications
Corner




Fiber-optic communications



IT S HARD TO STAY ON TOP OF THINGS

in consumer communications be-
cause we often find out that tomor-
row came yesterday. In other
words, we discover that tech-
nology we thought would take
several years to become econom-
ically competitive has actually
been available in ordinary con-
sumer appliances for years.

Fiber optics is just such a tech-
nology. It's been around for some
time in high-technology hard-
ware, and many news magazines
and newspapers have discussed
how it is used for interstate tele-
phone circuits buried in railroad
rights-of-way, in computerized
telephone-switching equipment,
and in Teleport, the super-duper
satellite-communications center
being built in New York City.

But those are very sophisticated
applications, so I assumed that I
could delay getting involved in yet
another new technology until it
became available in common, ev-
eryday hardware. Unfortunately,
fiber optics came in the basement
window while 1 was watching the
front door.

I discovered that my pocket
camera, my flashlight, and even
my home photocopier all use fiber
optics as a low-cost way to move
information from one point to an-
other. The key fact is that, while
fiber-optic technology is expen-
sive for mega-buck industrial
g uses, it often turns out to be an
z inexpensive way to do things in
? consumer hardware. To illustrate
o the savings made possible by fiber
ij optics, think about those home
a copiers. For a few hundred dollars
q you can get a copier that turns out
cc copies equal to those produced by



90



units costing well over $1000 only a
few years ago.

Naturally I was interested to see
how that feat was achieved. I
found that, instead of an expen-
sive camera and lens mechanism,
the copier uses fiber-optic fila-
ments to move the image from the
original to the copy. In a way, the
only difference between the cop-
ier and fancy telecommunications
gear is that the signal ends up on
paper rather than in an electronic
circuit.

So I thought that, if the tech-
nology was now low-cost enough
to be used in a home copier, it
must also be available in con-
ventional communication equip-
ment. Sure enough, seek and ye
shall find. Buried in the weeks
mail — under the copier's man-
uals — were computer-supply cata-
logs listing moderately-priced fi-
ber-optic modem for personal



-^CDG^







SBfSS



AMP



H>?=<na>*



PHOTO-
DETECTOR



HERB FRIEDMAN

COMMUNICATIONS EDITOR

computers. A fiber-optic modem
can couple a PC into a fiber-optic
communications cable; they
transmit data by light beam rather
than by electric current.

The reason why fiber optics can
serve equally well in desk-copier
and desk-computer applications is
that the fiber cable is really just a
means of conveying a signal from
one point to another. But unlike
wire, fiber-optic cable is wide-
band, essentially lossless, and
100% free of induced ground-loop
current. In addition, fiber-optic ca-
ble causes no interference to adja-
cent circuits. Here's an example of
the power of fiber optics: a single
fiber thread about the thickness of
a human hair can simultaneously
carry as many as 8000 multiplexed
telephone conversations.

How it's done

In actual use the fiber is a thin,
flexible filament that is usually
bundled with other filaments to
provide both physical strength and
multiple signal paths. The ends of
the fiber filament are ground flat
so its field-of-view is effectively
the diameter of the fiber, and that
makes it insensitive to illumination
that doesn't originate "head on."

As shown in Fig. 1-a, the fiber
cable carries an image of the input
illumination from one end of the
cable to the other almost loss-free.
However, that doesn't mean that if
we shine a 100-watt light bulb on
one end we'll get an image of the
bulb at the other (as shown in Fig.
1-5). Rather, the filament transmits
only the light that falls directly on
the filament; and of that light, es-
sentially 100% is delivered at the
output. The reason for that high



efficiency is that there is no inter-
nal toss due to heat, nor external
loss caused by spill outside of the
filament. All the light is contained
within the filament, and that per-
mits, two adjacent filaments to car-
ry independent signals without
interfering with each other.

A big problem in many elec-
trically-wired communications cir-
cuits is that of ground loops,
which are caused by circuit
grounds that are not true "earth"
grounds. In general, circuit
grounds are rarely true earth
grounds; hence there is a poten-
tial difference between grounds at
different points in a circuit, and
that can cause current to flow in
conventional cable-shields that
are grounded on both ends. The
current flowing between those
grounds often induces "hum" and
"hash" in the internal signal wires.
The fiber-optic filament is not sub-
ject to ground loops because fiber-
optic circuits use no shields or
ground wires; It's all done with
light.

A basic fiber-optic communica-
tions circuit is shown in Fig. 1-c.
The input signal is coupled into
the fiber filament by a light source
driven by an amplifier. At the re-
ceiving end, the fiber filament
points at a photo detector whose
output current (or voltage) is pro-
portional to the illumination from
the filament.

When the signal is analog — con-
tinuously variable across a range of
voltage — both the transmitter and
the detector must have a linear re-
sponse. Otherwise, the input sig-
nal could be digitized so that the
fiber-optic system would handle
only two states; on and off.

For example, in a fiber-optic
modem the computer drives a
small lamp that shines on the end
of a fiber filament. At the receiver
the filament shines directly on a
phototransistor, thereby coupling
the digital signal directly into the
receiving computer without the
need for a lot of complex analog
hardware.

Fiber-optic communications
hardware is still relatively esoteric
and expensive. But since it can be
used in home copiers, pocket
cameras, and flashlights, it won't
be long before we'll all be commu-
nicating by beams of light. R-E



STATE OF SOLID STATE



continued from page 89



Transistor Q1-a is in the op-amp's
feedback loop. That causes the
transistor's collector current to
equal the input current. Hence its
base-emitter voltage is propor-
tional to the log of the input cur-
rent. That logarithmic output
drives the emitter of Q1-b; that
transistor performs an antilog
function to provide linear output
for meter M1. The output of Q1-b is
scaled according to the position of
range switch S1.

The voltage across the divider
string (R6-R11) is stabilized by an
LM113 voltage reference diode.
That voltage is fed to the voltage
divider through a 2N2222 tran-
sistor configured as a diode, then
through calibration pot-
entiometer R4, and R5. The output
of the LM113 varies with absolute
temperature; that provides tem-
perature compensation.

To calibrate the circuit, potenti-
ometer R4 is adjusted for full-scale
deflection of the meter when a 1
|uA current is applied to the circuit.
That provides maximum accuracy
over all six ranges.

Micropower voltage regulator

The LP2950 micropower voltage
regulator is a recent addition to
National Semiconductor's line of
low-dropout regulators. The
LP2950 features a quiescent cur-
rent of only 75 ^.A and a dropout
voltage that is as low as 40 mv un-
der a light load. One advantage of
the LP2950 regulator is that its
quiescent current increases very
little under most conditions, and it
even stays low when battery volt-
age drops.

The LP2950 is available in 3-pin
and 8-pin versions. The former is a
5-volt, 100-mA regulator with a
temperature coefficient of SO
ppm/°C. Load and line regulation
are typically within 0.05%.

The output voltage of the 8-pin
version can be programmed from
1.24 to 29 volts with the addition of
an external pair of resistors. And,
by shorting pinsTand 2, the LP2950
becomes a 5-volt regulator. The 8-
pin version has several other inter-
esting features including an error



output to warn of low output volt-
age and a shutdown input that
permits the user to switch the reg-
ulator on and off using logic-level
drivers (a TTL gate, for example).
Both versions feature short-cir-
cuit protection and thermal shut-
down, and both require a 1-a.F
capacitor on the output pin for sta-
bility. The LP2950 costs $1.08 in lots
of 100 or more. — National Semicon-
ductor, 2900 Semiconductor Drive,
Santa Clara, CA 95051.

Eight-switch JFET array

The Sil800 from Siliconix is a
hybrid array of eight N-Channel,
high-speed JFET switches in a her-
metically-sealed package. It is de-
signed for 64K core-memory
circuits as a sense/drive switch for
military and industrial applica-
tions.

Each switch features high
switching speed (less than five ns),
low on-resistance (seven ohms),
high continuous drain current (400
mA), high maximum power dis-
sipation (300 mW), and a minimum
gate-source voltage of -25 volts.

The 16-pin flat package mea-
sures 0.285 x 0.44 inch (not in-
cluding leads), and it can operate
over the full military temperature
range. Unit cost of the.SilSOO is
$24.96 in 1000-piece lots.— Sil-
iconix Inc., 2201 Laurelwood Road,
Santa Clara, CA 95054.

Circuit design handbook

Circuit Ideas For Linear IC's is a
new 34-page handbook that offers
102 practical circuits using linear
IC's and MOSFET's. Each circuit
uses one or more of each type of
device.

The handbook is divided into
nine sections of industrial and
consumer applications. Among
them are sections on timing, mea-
surement, modulation, power
control, data conversion, commu-
nications, and alarm/monitoring.
Several indexes are provided; one
lists each circuit and the devices it
uses. A second index is arranged
by device number, the page on
which the circuit appears, and
RCA's data-sheet number.

A full schematic of each circuit
idea is shown along with a brief s
circuit description. For a free copy >
write to RCA Solid State, P.O. Box -
2900, Somerville, NJ 08876. R-E §



91



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KIRLIAN



continued from page 45



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posure using S2. As a guideline, start
with an exposure time of about 10-15 sec-
onds, but it is likely that you will have to
do a lot of trial -and-error experimentation
with both exposure time and oscillator
frequency, which is adjusted using Rl.
before you will obtain results that you are
satisfied with.

The author has had good success with
two types of film: Kodak 61 1 R Ektachrome




FIG. 6— ALTHOUGH THE RESULTS are not visu-
ally striking, Kodalith film is easy to work with.
Here is a Kirlian aura captured on that film.



and Kodalith 2556 or the film, type 3.

The Ektachrome film will give you
spectacular color transparencies, such as
the ones that accompany this article.
However, it can be difficult to work with (a
dark room is absolutely required) and to
develop. Unless you have a photographic
darkroom and are equipped for develop-
ing that type of film, you will probably
want to take it to a professional .

Kodalith 2556 ortho film, type 3 is a
high-contrast, black-and-white graphic
arts film that may be familiar to those who
use the photographic method to make
their own PC-board masks. The results are
less spectacular, as shown in Fig, 6, but
that film's light requirements are less ex-
acting (a photographic safelight can be
left on when handling the unexposed film
or making exposures) and the processing
procedure is much simpler, requiring just
three basic chemicals. The author has had
success finding the right exposure time
and frequency using the Kodalith, and
then turning to the Ektachrome for the
final exposure. fl-E



LEAKAGE TESTER



continued from page 58



it only for the test purposes intended, and
discharge tested capacitors with a screw-
driver when finished. In addition, use of
this project is recommended by tech-
nically qualified personnel only.

Now that that's out of the way, the unit
is a cinch to use. Let's look at some typ-
ical applications for the project:

Testing capacitors is easy. If applica-
ble, remove the suspect unit from the cir-
cuit first, as any external leakage can
cause a good capacitor to test leaky. Set S I
to the discharge position. Then set S2 to
the working voltage of the capacitor, If the
voltage is greater than the project can
provide, use the 1 00- volt position.

Then use insulated clips to connect the
capacitor to the project.

Flip SI to the check position. The
meter needle will "kick" upscale and
drop to zero for a good capacitor. If desir-
ed, press S3 for more sensitivity: that will
give you 0-1 mA readings instead of the
nominal 0-10 mA readings.

Note that the meter needle may kick
upscale many times before settling down.
That indicates that the capacitor has ex-
cessive leakage at the test voltage and
requires "fonning," That is a common
situation with capacitors that are used at a
voltage far lower than the working volt-
age, like, say, a 50-volt pan in a 12 volt
circuit. That is not a fault of the project.
However, if the meter doesn't slop kicking
after several minutes, the capacitor isn't
forming and should be replaced.

When the testing is finished, return SI
to the discharge position. The meter will
read negative, indicating discharge.
When the needle returns to zero, remove
the capacitor.

So how much leakage should a good
capacitor have? There is no simple an-
swer, as it depends upon the capacitor type
and circuit requirements. However, here
are a few rules of thumb you can use.

Paper, mica, polyester, and tantalum
capacitors should display no leakage.
Electrolytic capacitors up to 50 jxF should
show less than 25 u.A of leakage current.
Electrolytic capacitors from 51 |xF to 500
p.F should show less than 50 u-A leakage.
Electrolytic capacitors from 501 p.F to

1.000 p.F should show less than 100 u,A
leakage. Electrolytic capacitors from

1.001 u.F to 20,000 u.F should show less
than 500 u,A leakage.

Another use for the project is fonning
new capacitors. Understand that elec-
trolytic capacitors chemically deteriorate
when they sit unused. The capacitor's
electrolytic film, essential to capacitor
operation, deteriorates, causing very high
leakage currents. If you apply a voltage to
the capacitor, the film can reform. But if
that voltage is too high, that is, close to



the device's rating, the film may not be
able to form fast enough. So the capacitor
will consume power, get hot, and possibly
explode. Here's how to solve that problem:
Set SI to the discharge position and
S2 to the 3-volt position . Then use insu-
lated clips to connect the capacitor.

Flip SI to the check position and note
the meter reading. When the meter reads
minimum current, change S2 to the 6-
volt position. Continue increasing the
voltage until the working voltage is reach-
ed. Discard any capacitor that takes over
five minutes to form, or still has high
leakage when checked at its working volt-
age.

Appliance safety is easy to check.
Here's how: Set SI to discharge and S2
to 100-voi.TS. Assuming the device to be
tested uses a three- wire power cord, use
an insulated clip lead to connect the "hot"
side of the power cord to the positive bind-
ing post. After that, connect the ground
lead of the power cord to the negative
binding post. The return or common side
of the power cord is unconnected. If the
appliance does not use a three-wire power
cord, connect the negative binding post to
any exposed case screws or other metal
surfaces on the unit to be tested.

To test, flip SI to the check position.
Press S3 for more meter sensitivity. The
meter must read under 50 u.A. For higher
readings repairs are indicated.

Cables may be easily checked for leak-
age problems. Simply perform the checks
the same way you did for appliance leak-
age. Remember to always connect the
positive binding post to the center con-
ductor and the negative binding post to the
shield; that prevents a shock hazard.

If you need more sensitivity when per-
forming leakage testing, try using your
DMM if it has a 200-u.A DC range. Sim-
ply set it to the 200-u.A range and connect
it in series with the positive binding post
and the cable under test. That technique
works great for other applications, except
testing high- value capacitors. With those,
when you switch to discharge, the cur-
rent from the capacitor passes through the
DMM, overloading it.

Another use for the project is quickly
checking those special high voltage di-
odes used in TV sets and microwave
ovens. Usually a DMM can't check those
components because it can't supply-
enough voltage to turn on the device.

To test the diode, set SI to discharge
and S2 to 100- volts. Then remove the
diode from the circuit and connect it to the
project's bind ing posts. Flip SI to chixk
and note the reading. Then return SI to
discharge and reverse the diode. Flip SI
to check again and note the reading. With
most silicon diodes we expect a full-scale
reading when the diode is connected one
way and zero when it is reversed. With
selinium diodes, the difference should be
at least 100 to 1. R-E



94



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ings, diagrams and photos. We show you how to troubleshoot
and repair video -cassette recorders and TV sets, how to handle
house calls and shop repairs lor almost any make of television or
VCR. Tools are induced with your course so you can get
"hands-on" practice as you follow your lessons step by step.
Send lor free fads about the exciting opportunities in TV7VCR
Repair and lind out how you can start making money in this
reatcareer MAIL COUPON TODAY



ri






Quality Microwave TV Antennas



Mum-Channel 1.9 to 2,1 GHz
I 40dB Gain True Parabolic 20 Inch Dish
^^M Complete System $84.95 (Shipping hid.)

H Dealerships. Qty. Pricing. He placement Parti

I PfillHus-TBCli Electronics

&**r?- P.O. BOX M77Z - fHoetlllt. HZ B5067
lifetime 1602)947-7700 |S3.(M Credit ill phone ardersl)

WARRANTY MlslnCinf ? Vtsi ? COD'S



SCHOOL OF TV/VCfl REPAIR, Oepl DE04S

Scranlon. Pen nsylvania 1 85 1 5
Please send me lull information and color brochure on how I can ■
learn TV/VCR Repair at home in my spare time. I understand I
there is no obligation and no salesman will visit me.

Name. Age ■

Address ?



City/Slate/Zip. —
Phone ( )_



FOR SALE



ELECTRONIC surveillance: Amazing books reveal
secret techniques used by professionals,A.T.I.S.,
1107 50th St. Fennville, Ml 49408.

CABLE-TV f 1 1 ters for e I i m i nation of u nd esirable sig-
nals. (50 rJB. notch) channels available: 2 through 8;
14(A) through 22 (I). Send $20, each. Money back
guarantee. Quantity discounts. CATV. Box 17621,

Plantation, FL 33318.

ELECTRON TUBES— radio, TV & industrial
types— huge inventory. Call toll free (800) 221-5802
or write Box ESC TRANSLETERONIC, INC, 1365
39th St., Brooklyn, NY 11218. (718) 633-2800

CB'ERS only: antennas, radios, modulators,
voice scramblers frequency expanders, modifica-
tions, goody boxes, professional repairs, much
more! Free catalog. PRESIDENT C,B SALES, 101
W. Adams-12, Long Beach, CA 90805. (213)
631-3552.



BUGGED? Wiretapped? Find out fast. Counter-
measures equipment catalog $1. CAPRI ELEC-
TRONICS, mute 1R, Canon. G A 30520.

WANTED: Western Electric, RCA, Mcintosh, Mar-
antz, Levinson, Tannoy, Dynaco, Altec, JBL. tubes
speakers, amplifiers, (713) 728-4343 MAURY 11 122
Atwell, Houston, TX 77096.

DESCR AMBLER manuals, sinswave, gated pulse,
SSAVI, $4.00 each, all three $10.00. DNF, 6690 7
Mile, S. Lyon, Ml 48178.

ASSORTMENT #103 - consisting of Toko
coils 144LY-120K, 520 HN-3000023, BKAN-
K5552AXX (2); PCB; transistors 2N3904 (2),
BFQ85 (Sub); IC's 7812, 74123,
MC1330A1P; Diodes 1N914, 1N5231B. Only
$25.00. Coils (only) S8.00/SET AC Adapter
$6.00. Free shipping. MC/Visa/COD. Toll
free 1-800-821-5226 Ext. 426 (orders). JIM
RHODES, INC, 1025 Ransome Lane, King-
sport, 1H 37660.

TUBES, name brands, new 80% off list, KIRBY.
298 West Carmel Drive, C arm el IN 46032.

TUBES, new, unused. Send self-addressed, stamp-
ed envelope for list. FALA ELECTRONICS, Box
1376-2, Milwaukee, Wl 53201

CORDLESS copy phone interference? We've got
the answer. Have a radar speeding ticket? We can
help. Home phone extension in your car? You can
have it. 50-page color catalog airmailed $3.00.
DBE, P.O. Drawer G, Waikiki, HI 96830.



OLDTIME radio programs on high quality tapes.
Comedy! Adventure! music! Free catalogue, Carl F,
Froelich, Heritage Farm, New Freedom, PA 17349.

TV tunable notch fillers, free brochure D.K VIDEO,
Box J^6025, Margate, FL 33063. (305) 752-9202.

LIGHT chaser, color organ controller, rope lights,
triggerable neon power supply. DESIGN SPECIAL-
TY, Box 1995, Huntington Beach, C A 92647.

TUBES: "Oldies", latest. Parts, components, sche-
matics. SASE, for list. STEINMETZ ELEC-
TRONICS, 7519 Maplewood Ave., R.E., Hammond,
IN 46324. ___

LINEAR PARTS, TUBES, TRANSISTORS - MRF
454 516, MRF455 $12, MRF477 $11 , MRF492 $18.
Catalog. RFPC Box 700, San Marcos, CA 92069.
(619) 744-0728.

D ESC RAMBLERS for downconverters. High gain.
Send S2.00. RB ELECTRONICS. P.O Box 643,
Kalamazoo, Ml 49005.

CONVERTER descrambler schematic, service
manuals, cable and satellite, Mew Oak cable de-
scrambler $35.00, Varisync units ?45.00, no Colo-
rado sales, call (303) 634-6666 for special wants,
POUDEROSA COMPANY, 2408-A East Platte,
Colorado Springs, CO 80909.

RESTRICTED technical information: Electronic
surveillance, Schematic, Locksmithing, Covert sci-
ences. Hacking, etc. huge selection. Free bro-
chure: MENTOR-Z, 135-53 No. Blvd., Flushing,
NY 11354.

INDIVIDUAL photofact-folders #1 to #1400. $3.00
postpaid. LOEB, 414 Chestnut Lane, East Meadow,
NY 11554.



CB MODIFICATIONS



Increase channels, range, privacy! We specialize
in frequency expanders, speech processors, FM
converters, PLL & slider Wicks, how-to books,
plans, kits. Expert mail-in repairs & conversions.
16-page catalog $2. Our 11th yearl



CBC INTEflNATIONAL, P.O. BOX 31500RE.
PHOENIX. AZ 85046



CO
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O

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96



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ICRO
RflT



1 5 Pin H?d*r I Mating Sock?.
V?rt MT/PC

.1 56" Cantors .,, . . ? 5/1 Op

JumboGrecnLED's l5Sl.ilMSS.Cio

3.30Q|iF 35V AXIAL-1 V2'v flfl u Mich 2'.95

Colli For Radio El?c'? F??- 04 TV
Project. Toko n'ST-1. T-2. L-1 !12uH)
& L-2 (.071 uH) C a i mi l./ii.- Sot Ot All

4 Colli 8.50

MCI 330— Prime IMoto) ... 2/1.00

BFQ'85 Transistor 1.50

Disc Gaps .001 u(. .. 20/t.O0

74123-PrimelNa!) 3/1.00

470ul 35V (Radial). 371.00

470ul 1 6V (Axiail . . 4/ 1 00

2N3904. .. 10/100

2N3906 10/t.00

1N914 40/1-00

1IM4148 40/1-00

1N5S316I5 IVZenerOiOrM 5/1.00

VollageBegulaloralPnmeTO-220) ... 7605.
7B 1 2 . 7824 , 7905. 79 1 2- M IK or Ma[ch-3/ 1 00
Mica Insulators For TO- 220 Pku . 20/1.00
Voltage Reg's [Unmarked, 60% Prime} May
Include Positive/ Neg ? Adjust .. IS/1.00
78 LOS Vol! aga Rag I D M 1 06 , TO- 92] .20/1 .00

PN2222A 20/1.00

2N3055 SO

Logic Probe [Pencil Type) . 18.95

Logic Pulscr (Pencil Type) 18.95

Zanem nj-Sai). 1NJ735AS 1N4719A . 30 SI
Relay-SPST 12V Coil. Normally Closed

Conlaels Open Wkun Energized 95

Ecgeeard Conn 15 30 Pin 156" Clrs 65

6 32 Screw. I n S1and Oil Terminal . . 20S1

Lto3(]9K IMC7305CKI Reqolelor 75

1 5 C?nt (, 1 5) Per IC 74LSXX
74LS02 74LS32 74LS1SS

74LS08 74LS74 74LS174

74LSIO 74LS36 74LS257

74LS20 74LS153 74LS273

20 Cent (.20) Pur IC CMOS
4001 8. 401 1 B. 4050B. 4051 B

MCB38(CTU ." .10/1.00

auk irjnv Mylar Cap IAXI 20 51

2ri6Epiom... . 1.45

2732 Eprom 1.95

2764 Eprom ....2.4S

271 28 EPROM 4,95

250K Oram 1 50ns Prime Hitachi lldeal For
Mac Upgrades & Expansion Projects). .4.95

S243 (I/O Expander IC) W/Soeoa. 2.SS

U DN 6 1 1 8 c uisplay ur-ver I C- Specs) 85

UDN6128 ... ... 95

UCN 41 1 SB-Osc/Freg Oiy Clock iOSeecs-5/i

2N3643lNPN10-92iPla5lic. 1081

LM339 . .45

LM380{ULN22BOI.... 45

555 Timers (TT) 4/1.00

NtE556(DualT>mer,Moto F . . .80

741 Op Amp 4 1.00

LMi310rUnmarked. Tesled Pr.mel .. .50



\ BOS Central Ave, /

\ WMtkH NJ. 07000/

\ (201)654-8008 /

LM390O .45

AM/FM Radio IC 1*2204 W/sbecs-Mobbyl

15/1 00

IC Socket!

a PIW 07 14 PIN/. 13 16 PIN/. 15

18 FIN/ 17 20 PIN/ .19 22 PIN/ .21

24 PIN/ .22 28 PIN/ .24 40 PIN/ .39

7SegmentOisplay(.3'Commoncatn). 15
7 Segm ent Display ( 6 ' Com mon Annt . . .65

Tn Stale LEO 5. .3/1.00

Jumbo Red LEDs-DiNused Lens. Prime (Tl] All
irxj".Pnma 1SS1. 100S6. 1.000SS7.50

LED Mounting Clip* a Rings... ... 15/1.00

.tuF 200V Mylar Film IAX| IS SI

UON7180 tSegment Driver IC Data! 65

Dip Switch- 12 Position. 2/100

Dip Switch-B Position 4/1.00

Keyboard Push Botlon Tops 30/1 .00

Audio Cable 30 Feel/1 .00

22AWGWire 50 Feel/ 100

27AWT3Wire 50 Peel/ 1 00

Mini Lubricator fo LiibricantJ ..1.00

Molex PinsfT Pin/Strip! 1 0O/S2.50O/S4.1 K/I6

MC145B (Dual 741) 4/1.00

ULN2274 (Dual Audio Power AMP 75

Rolary Swilcn (5 Posit?on, 5A l25V)-3/1,00
Giant Alpha Numeric Display 1-1/2 X 2'
7X5 (35 Tolal) Red LED Malrix/Specs-4.95
11 LED ear Graph Dliptiy-2-3/4". Reel
LED'a (Specify Red Grn.Amb) Specs . . - 2.69
SflvmAmpl 71 Tipped Transformw-Can Be
Wired For| 7.5V.9V. 1 5V. 1 8V] Reg Shpg . . 8.95
WallPlugTrans!ormer-24V525mA. .1.50

S3V 1.2ATranslormer.. ., 1.20

12V Center Tap Transformer 2.95

SAMP 200V Bridge. Ckiick Oisconnect (01) .95

1N4007 20/100

1N5059 (200V 1 Amp) : 15/1.00

1 N5060 (400V 1 AmpJ 10/1.00

Zener Diodes-20V1W .... 30/100
Zener Diodes- 1 3V 1 W Glass. . . . 30/1 00

2560.0KC Crystal .50

3579545ColorBurslCrys(alr HO 18).. .50

1 Mhi Crystal 1 .95

6.0 Mhl Crystal ... 1 ,95

TO-5 HeatSinksiBern) lO/l 00

TC-ISHeatSinks(Bern) 101/1.00

Super Sub-Mini Ceramic Caps (All 10oV)
,0015uf 100Vf1S2] . . . .30/100

0022uf 100VI182) . 30/100

0027 uf 100V 272,.. . 30/1.00

J5033ut10OVl332l 30/1.00

0039u( 100V1392I. . 30/1.00

005,. 1 100V (552 1 ., ..10 1.00

0082ur 100VI822) 30/1.00

4.7ut 40V Lytic (Radian 20/1.00

47ul 25V Lytic I Radial) . 10/100

lOOOul 1B5V Twist Lock 1.00

3200 ul 50V I Ideal For Power Supplies)- 1.00
5600 ut 25 V (Comp Grade 3-5/B" X 1 )-3/ 1 .00

. 1 uf 50V Monohlhics 10/1.00

.01 ufSOVMonolithics 20/1.00



Chip Caps-Sel o! 4. 2 Each 2.7 1 3. 3 pf- 1.00

33uf 100V Dip Mylar 10/1.00

IN4004 Oiodes 30/1 .00

Fots-1 Meg, Linear Taper .5/1.00

Motion Defector Bds( I nc IC-82) . . . 7/10.00
MotDet(ICOnly.(JLN2232?3/S2-2O/t0.00

Project Box/Lid For Detector 1.95

Miniature Speaker For Deteclor .85

Extensive Gonslruction Article For Del. $1

TV Knots. 1 5/1 .00

Ammeter (r>15 A.C. Amperes) 4.95

volt/OHM Meier MVMNT (0-1 K OHM.

0-300V) 2.95

6V Miniature Gear Mold/. . -.: 50

RFChokes-l.Suh. B.2uh, 1 2uh. 22uh-10/ 1 .00
40 Pin Flat Cabte Socket Connector/Hood .40
SOPinFlalCableSocket Connector'Hood .50
14 Pin Dip Header Plug Mate I3M) . . . 3.'1.0D

Mixed Connector Assl 10/1 .00

I.5AMP50V Bridge H3I. TO-5 Pkg). . ..50
25A MP 200V Bndgel Solder Lug Term). .. 1.50
Zenith TV Replacement IC Special SI Each
221-42. 221-43. 221-45. 221 -4B. 221-69,
221-79, 221-87, 221-96, 221-1 04, 221 - 1 05.
221-106.221-140

2SD900(Horii Output W/Damper Uiode)-2.95
2SC1172B1To5hib-HorizOurputTrans)-l.95
Winegard48ay8owtieUHFAnlenna-19.50
IC Storage (Bug) Box (Holds) 30 ECs-2 25
Precision (Murfi-Tutn) Trim Pots (Copal).
100 OHM, 50O OHM, IK, 2K, 5K, 10K,20r1;
50K, 1O0K, 200K. 500K. I M-,65 Each-3/I2
PlhwPT-10V Hor Mt(SJn S leTum| Trimmer
lOOOhm. 1K 5K. 10K 25K 50K. 10OK. 20TJK.
500K 1M 25 Each

Mixed Coil Ass't .10/1-00

Suizers 3/1 .00

Chip Resistor (SB X) 20/1.00

ChioResiSIOr(470K) 20/1.00

Chip Cap (330pll 20/1.00

36 PIN Rt. Angle Header Connector 50

MRF90 1 ( Hoboy Grade^O* Grxso) . . . 1 Ofl .00
IC Ass' I ( Hobby Grade.SomeMarked)-30/51



20Cent(.20)74SCXX
Series Special

* Octal I ntvrlic* Circuit!

* Equivalent To 74USXX S*n*s

? Low Power ISO-CMOS T*crinolcgy

? Short Propagation Daisy

* Improved Kola* Margin*

? High Current, Si nk/Source Capability
74SC137-. OiB I nven^d Decoder. Latched
74SCt3fi-i Of S Inverted Decoder
74SC139-1 Of 4 Inverted Decoder
74SC237-1 O- 8 Non-Inverted. Lalched
74&C23S 1 01 S Nor.- Inverted
74SC239-1 OM N o n- inve rted
74SC?40-Oclal Buflei/Lme Dfiver-lnv
74SC24 1 -Oclal Burier/Line Dnver-N/I

74 SC2 4 d -Octal BuIfer^Lme DnverN, 1 !
74SC24S-Octai Bus TTartsceiver-Nonl
74SC37 3 Transcalent Latch- Non^lnv



?4SC3r4-DType Flip-Flop. Nan/liw
74SC533-Tran3parar,i Latch- Inverted
74SC534-DType Flip-Flop, Inverted
74SC540-Octal SuTfei/Line Oriver-lnv
74SC54 1 -Octal BulFer/Lme Driver- Hf I
74SC563-Tranaparenl Latch, Inverted
74SC564-D Type Flip-Flop, Inverted
74SC573-Transparen1 LalCh. Non/lnv
74SCS74-D Type Flip-Flop. Non^lnv
Data Book For All Above #"s 2 50



Cypher IV Mkcro-Controtler Kit $129.50

? 4 MHl. G-Bit IVltcro processor"
(NAT 1 NS8073J

? Corilroi Basic imarpreter On-Chip

? Ay(o-S(art Op-station a; Power On

? Fas) 1 6-Bii MuHipiy And Divide

■ RS-232, Supports CRT i Serial Link

? 24 9 1- Directional I/O Lines L&255Ah

? RAM MemorWK Expandable TojGK
? Eprom Memory' Expandable To ^cK

? Built In Eprom Programmer

? PaffiCenlroni)(| Prinler interface
?Optional Real-Time Clock W/ Back up



Pay TV Hardware inatalletion KH Blow Out
As Low Aa*2.S5 ^ S3 50 Shipping Per Unit
All Kils Conlain 5 F Conneclors. 300 to 75

OHM Balun 300 OHM TerrnmaJ Block 2 F1

75 OH M Patch Cord 2 Ft 300 OH M Twm L ead.

Nyton Cable Ties, And UHF Antenna

Modal #41 24-*2;95 Indiides AH 01

The Above Pius 25 Feel Coaxial Cable And

Mounling Hardware For indoor Wall'Ceilmo

Installation

Model V4BSO-32.95 Includes AM Ot

The Above Plus 25 Feet Coaxial Cable And

AlEractive Expandable Pole/U-BoM For

Easy indoor Installation

Modal *4845 S395 Includes All 01

The Above Plus 65 Feel Coaxial Cable And

AH Necessary U'Boii Hardware



model 70s Digital Mu.timeter



DC Vf.in-a-i 10Ql>V !.'■ 1Q00V

AC vol I*.;* KlOtiV to 730V ?C4 Q*.

OCCunfcil O.lnAtoKW *0 I W3

AC Cj'icnl 0,1 PA to 10A ** ■

Hi l..- R.inlanci Q.1Q loJOMU

CjpacilancB 1pF tit 10 Uf"

Dtedt t?si letrwtrd vom^a Ht*tln v
mnilabfx tMllitg



UHF-TV PREAMP

4As leatured in Hadho Eleclronics March/
kAay articles. 1i932 p

7'<:.\ inexpensive antenna mountitd pre-
amp can add mom than 25 dB of gar'n to
yout system. Lots ot satisfwi customers
and repeat orders tor this high :,??.?.,:.:■,- hit,
which inciuttes at! component parts, PC
BD. Casa. Power Suppty and Balun S34.50
AssemttiQtJ Version .157.50



Ttnei: MICRO-MAflT accepts Visa MC am, terephope COUs Mjiwhjih cfder SlO.OO Shippirna-
U S orrjers, 12 00. Canada and other countries 13.50 (irtcLudes ins). Shibpinrj rate adjusted where
applicable NJ resirjenrs add 0% sales tax

MICIO-HUT ? 501 CEKTHAl ME,, WESTFIELD. NJ 07090 * (?1) I6M00I



CIRCLE 272 ON FREE INFORMATION CARD



WRITE FOR



SPEAKER & ELECTRONICS CATALOG

1001 BARGAINS IN SPEAKERS

toll free 1-800-346-2433 tor ordering only,
1901 MCGEE STREET KANSAS CITY, MO 64106

RESISTORS v, W, Vi W 5% C.F. 3 cents 1% Metal-
films. custom wirewounds, capacitors and other
components, JR INDUSTRIES, 5S34-H

Swancreek, Toledo, OH 43614,

CATALOG: Electronic components at budge! prices
for students, hobbyists and industry. Send $2.00 P
& H (refundable) BUDGET ELECTRONICS. Box
1477, Moreno Valley, CA 9233B.

TEST equipment, reconditioned. For sale. S1 .25 tor
catalog. W&LTER'S, 2697 Nickel, San Pablo, CA
94806 (415) 724-0587,

SOLAR ELECTRIC PANELS from $250! Inverters,
95% efficient. GIL ELECTRONICS, P.O. Box 1628,
Soquel, CA 95073.

RESISTORS .01. 2N3904 .05, 1N4148 .02, more.
Flyer, 2 stamps. DIGIMATION, Box 1479,

Cuilowhee, NC 28723.

PARTS, IC's, Transistors, Capacitors, Resistors,
Solar Cells, Plans, Kits, More. GIL ELECTRONICS
Box 1628. Soquel, CA 95073.

ELECTRONICS Bonanza large lot excessed equip-
ment closed circuit TV, medical/scientific, computer
testing, groung-to-air communication, navigation
aid apparatus, many miscellaneous items,
HAROLD GARRETT OKC OK call for complete list
(405)6B6-O031.

MINIATURE FM Transmitter, size of postage stamp.
Up to 1 mile range. Kit $24.95 includes PC board
and all board mounted parts. Catalog $1.00 refun-
dable with order. (CA residents add 6.5%) CAS
ELECTRONICS. 1553-J Amar Road Suite 457.
West Covins, CA 91792. __

WHOLESALE MATV/CATV Equipments, antenna,
accessories, cartridges, radios, speakers, cables
(718) 897-0509 DAWR, 58-12 110 St. Flushing, NY
11375.

OP AMPS - Lowest prices for popular types. Send
for list. ELAN TECHNOLOGY, RD1 Box 546, Ring-
oes, NJ 08551.

35-70% Savings-Bargain catalog for 39 cents
stamp. APEX ELECTRONICS MOD, 8909 San Fer-
nando Sun Valley, CA 91352.

RECTIFIERS, Parts (or automotive battery charges,
A&E EQUIPMENT, 4617 Highway Jacksonville, FL
32205 (904) 388-2953.

DESCRAMBLER - Complete Zenith SSAVI-1 sys-
tem (can't be disabled) $150.00, WATSON, 342
Franklin Framingham, MA 01701.

LASERS and nightvision surplus components, free
catalog, M.J. NEAL COMPANY, 6672 Mallard Cl?
Orient, OH 43146.

CB tune-up manual volume II. Specific adjustments
and modifications for peaking all popular CB's.
Covers over 1300 radios $19.95, Visa, Mastercard
to: THOMAS PUBLISHING, 127 Westwood Paris,
IL 61944.

ELECTROLYT1CS 10,000 (iF 70WVDC individually
tested $3.50-$12/4 add $1.00 postage per order.
C.L. MARCH. 3010 BriarwOOd, Hornlake, MS
38637,

SCIENTIFIC Atlanta stand alone descrambler
priced under $100. Details $2. DIGiTEK, Box 195,
Levittown, PA 19059

R A D A R Jamme r- $1 95 .00 i nterface for rad ar detect ,
optional Visa, Mastercard, COD. Qua nitity discount
V-G ELECTRONIC, 2724 Bonnie Drive Cincinnati,
Ohio.

CABLE and SUBSCRIPTION TV secret manual.
Build your own DESCRAMBLERS, converters. In-
structions, schematics for sinewave. inband/oul-
band. Gated sync. SSAV1-(HBO, Showtime,
Cinemax, UHF, etc.) Send $8,95 to
CABLETRONICS, Box 30502R, Bethesda, MD
20814,

"CABLE converters, satellite receivers, de-
scramblers, & other audio/video equipment.
Federal sales law enforced. CEB, Box 16305,
Davenport, IA 52806, (319) 322-6668."



CABLE-TV




BONANZA!



ITEM



RCA 36 CHANNEL CONVERTER (CH. 3 OUTPUT ONLY)



PIONEER WIRELESS CONVERTER (OUR BEST BUY)



LCC-58 WIRELESS CONVERTER



JERROLD 450 WIRELESS CONVERTER (CH. 3 OUTPUT ONLY)



SB ADD-ON UNIT



BRAND NEW — TRIMODE UNIT FOR JERROLDS



MINICODE (N-12)



MINICODE (N-12) VARISYNC



MINfCODE VARISYNC W/AUTO ON-OFF



M-35 B (CH. 3 OUTPUT ONLY)



M-35 B W/AUTO ON-OFF (CALL FOR AVAILABILITY)



MLD-1 200-3 (CALL IF CH, 2 OUTPUT)



INTERFERENCE FILTERS — CH, 3



JERROLD 400 OR 450 REMOTE CONTROLLER



ZENITH SSAVI CABLE READY (OEALER PRICE BASED ON 6 UNITS)



SINGLE
UNIT
PRICE



29.95



88.95



92.95



105.95



DEALER

10- UNIT
PRICE



1 8.00 ea,



72.00 ea



76.00 ea



90.00 ea



109.95 58.00 ea



Call for specifics



109.95



119.95



1 79.95



139.95



199.95



109.95



24,95



29 95



225.00



58.00 ea



62.00 ea



115.00 ea



70.00 ea



125.00 ea



58.00 ea



14.00 ea.



1 8,00 ea.



1 85.00 ea



SPECIFY CHANNEL 2 or 3 OUTPUT



Other products available — Please Call



Quantity


Item


Output
Channel


Price
Each


TOTAL
PRICE






























































California Penal Code 8593- D forbids us


SUBTOTAL




from shipping any cable descrambling unit
to anyone residing in the stale of California.

Prices subject to change without notice.


Shipping Add'

$3.00 per unit




COD & Credit
Cards — Add 5%




PLEASE PRINT


TOTAL





Name



Address
State



.City.



D Cashier's Check

Accl #

Signature



. Zip

□ Money Order



. Phone Number ( )

□ COD O Visa
Exp. Dale



□ Mastercard



FOR OUR RECORDS:

DECLARATION OF AUTHORIZED USE — I. the undersigned, do hereby declare under
penalty ot perjury that all products purchased, now and in the future, will only be used on cable
TV systems with proper authorisation trom local officials or cable company officials in
accordance with all applicable federal and state laws.



Pacific Cable Company, Inc.

7325Yz RESEDA BLVD., DEPT. #R-4- RESEDA, CA 91335
(818)716-5914 ? No Collect Calls ? (818)716-5140



IMPORTANT: WHEN CALLING FOR INFORMATION

Please have the make and model # ol the equipment used in your area. Thank You



>

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to

CO



97



Saratoga Electronics




ORDER TOLL FREE



800-621-0854
arf.245



DYNAMIC RAMS



4164 - 150NS
41256 - 1501VS



I.C's



M58725

9114EPC

74S374

74S280

8237A-S



EPROMS



2716 - 450NS
2732A-450NS
2764 - 4 SONS
2764 - 250NS
27256 - 300NS



SI. 25
S3. 25



S1.49
S.90
S.39
S.39

83.50



82.95
82.25

S3.00
83.75
86.75



PC/AT COMPATIBLE
SYSTEM BOARD

$895

* 1 Megabyte Installed



DRIVES



MIT 4853 QLiAD/DS 96 TPI

ViHT. 869.95

TM848-2 8" DS/DD VbHT. 899.95

SEAGATE 20MB VsHT. S375.00

QUANTUM 40MB FULL HT. 8795.00

HARD DISK CONTROLLER

(OMTI 5510) 8139.00



PC/XT COMPATIBLE
SYSTEM BOARD

* 256/640 KB ?/?. bios a r.?

$160



Ask About Our PC/XT
System Kit

S895



?25 MINIMUM ORDER
PRICES SUBJECT TO CHANGE



12380 SARATOGA - SUNNYVALE ROAD

SARATOGA, CA 95070

(408) 446 - 4949



TI-99/4A software/hardware bargains. Hard to find
items. Huge selection. Fast service. Free catalog.
DYNA, Box 690 HicKsvitle, NY 11801.



A SINGER'S DREAM!



REMOVES VOCALS FROM RECORDS!

Now You can sing with the world's best bands!
The Thompson Vocal Eliminator can remove
most or virtually all of a lead vocal from a standard
stereo record and leave the background!

Write or call for a free brochure and demo record.

L"l Sound, Dept. R I, P.O. Box 338,
Stone Mountain. GA 300S6 (404)493-1258



PLANS AND KITS

CATALOG: Hobby/broadcating/1750 Meters/Ham/
CB: Transmitters, amplifiers, antennas, scramblers,
bugging devices, more! PANAXIS. Box 130-F5 Par-
adise, CA 95969. ^^__^_

CABLE TV CONVERTERS: Jerrold products
include "New Jerrold TRi-MODE", SB-3.
Hamlin, Oak VN-12, M-35-B, Zenith, and
more. UHF deluxe II Kits. (Quantity dis-
counts) 60 day warranty. Service convert-
ers sold here. For fast service COD orders
accepted. Send S.A.S.E. (60 cents
postage) or call for Info. (312) 537-4408.
HIGGINS ELECTRONICS 5143-K W. Di-
versey, Chicago, IL 60639. No Illinois or-
ders accepted.

HI-FI speaker kits, auto speaker systems and
speaker components (rom the world's finest man-
ufacturers. For beginners and audiophiles. Free lit-
erature, A&S SPEAKERS, Box 7462R. Denver, CO
80207 (303) 399-8609.

fl' DISH $69 fabrication cost. Polar mount, attrac-
tive, easy construction. Stock hardware items used.
COMPLETE instructions, plans, fabrication, assem-
bly, setup, drawings, photos. $14. 95 Plus $2,00
shipping. DIRIJODISH. Box 212 Lowell. NC 28098.

FREE catalog 99-cent kits — audio, video, TV com-
puter parts. ALLKIT. 434 W. 4th St., West llsip, NY
11795.

CRYSTAL radio sets, plans, parts, kits, catalog
$1.00 . MIDCO, 660 North Dixie Highway, Hol-
lywood. FL 33020.

PROJECTION TV. ..Convert your TV to projecl 7
Foot picture... Results comparable to $2,500 proj-
ectors.. .total Cost less than $30.00. ..Plans and 8"
Lens $19. .95. .Illustrated information FREE. MAC-
ROCOMA-GI, Washington Crossings, PA 18977.
Creditcard orders 24 Hours [215) 736-3979.

FILTER DESIGNER KIT a variable gain state varia-
ble filter. May be reconfigured to build most of the
circuits in Don Lancaster s book 'Active Filter Cook-
book". Send for free brochure, KEY ELEC-
TRONICS, Box 1, Red Key, IN 47373.

DESCRAMBLER plans, New design decodes
gated sync suppressed signals — newest pilotless
method. Circuit boards, most parts from Radio
Shack. Detailed theory, drawings, schematics, in-
structions S14.95 plus $2.00 shipping. DIRIJO
CORP., Box 212, Lowell, NC 28098.

FREE EVALUATION

and ADVISORY SERVICE




A HON PROFIT
ORGANIZATION



For prslmlDfiil Blictronlc Itchniclmt
by prestigious non-profit organization.
Earn University Degree (Bachelors or
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given for previous schooling and
professional experience Upgrade your
earning power Free Details'
CONTINENTAL EDUCATION ASSOCIATES
Fjt Bon 1197 - Ctumpltln NT 12816119;



C-54 interface boards, plans and software. Control
robotics, ultrasonic security, appliances, phone an-
swering, and mote, with ease you never thought
possible. Put your computer to work! Send SASEto
BYTEX, 189 Western Avenue Lynn, MA O1902

MASTERCARD AND VISA are now accepted
for payment of your advertising. Simply
complete the form on the first page of the
Market Center and we will bill.

SATELLITE TV

SUPER LNA kits, dxtvpreamps, microwave compo-
nents, ir detectors. LSI. Box 7553, Jackson. MS
39204.

DESIGN and build Satellite dish antennas, easily,
economically, illustrated manual, $9.95, DNF, 6690
7 Mile, S. Lyon, Ml 48178.

STEREO TV ADAPTER KIT Easily converts any
TV/VCR to receive the new stereo TV sound. Con-
tains all parts PCS and instructions to build a quality
stereo decoder. For additional information send
SASE to SOKOLOWSKf— Box 150, Elmont, NY
11003

DO-IT-YOURSELF complete 10' Satellite System
$1143.00 UPS shippable. Easy to understand in-
structions. MIKE'S SATELLITE & ELECTRONICS.
605 E Willow, Duncan, OK 73533 1-405-255-2234.

E-Z Satellite Kit" computer print-out of your loca-
tion, compass, angle finder $19.95 Free catalog,
Mastercard/Visa IN-X-SALES. Box 45, niton, NH
03276 (603)286-3082. __^_

55 DEGREE LNA's! Brand name! Improve your Sat-
ellite System! Convert block systems to Ku-Band.
Replacement LNB's. Discount pricing:LNA. 201 E
Southern Suite 100A, Tempe, AZ 85282.

BUILD YOUR OWN SATELLITE TV RECEIVING
SYSTEM AND SAVE! Instruction manuals, sche-
matics, circuit board, parts kits! Send stamped
envelope for complete product listing: XANDI,
Box 25647, Dept. 21A, Tempe AZ 85282.

CABLE TV SECRETS-the outlaw publication the
cable companies tried to ban. HBO, Movie Chann-
nel. Showtime, descramblers, converters, etc. sup-
pliers list included. $8.95. CABLE FACTS, Box 711-

R, Palaskala, OH 43062.

SATELLITE systems $449 catalog $2. Also: KU
band systems. STARLINK, INC., 2603-16R Artie,
Huntsville. AL. 35805.



PAY TV and Satellite Descrambling.



73 pages of theory and schematics (or all major sys-
tems. Fantasy and Amk-D schematics included. Wosl
compleie reference available on satellite scrambling
?12.95, MDS Handbook $10. Slungun schematics $5.

Satellite systems under ?600.. ?11 95. Printed circuits.
kits catalog ?1.



SHDJIKI ELECTRONICS CORP. I327R Niagara Slreel

Niagara fails Wi M303 COD s 716-284-Z163



REEL-TO-REEL TAPES

AMP EX professional series open reel tape. 1 800-0 r
2400-feet on 7-inch reels. Used once. Case of 40.
$45 00. 10 1/2 x 3600 feet and cassettes available.
MasterCard Visa. VALTECH ELECTRONICS, Box
6-RE, Richboro, PA 18954. (215) 322-4866.

EFROM PROGRAMMING

HOBBYISTS: Pretested EPROMs sold with your
programming installed. Program listing provide.
Fast Service. Write or call: "ROMULUS MICRO-
CONTROL, Box 8669. Rockville, MD 20856; (301)
540-8863.

ALARMS/HOME PROTECTION

BURGLARIZED? Professional Quality Infrared Mo-
tion Detector Kits. Easy Installation. Wireless
Equipment available. REFUNDABLE Catalog
$1,25. GTECH SECURITY RE-1. 11221 Inter-
state-10. New Orleans, LA 70128.



INVENTORS



INVENTORS! Can you proli
AMERICAN INVENTO



from your idea? Call
RS CORPORATION for free
information. Over a decade of service.
1-800-338-5656. In Massachusetts call (413)

568-3753.



98



CIRCLE 261 ON FREE INFORMATION CARD



*Q U ^1^SC0^ PW f FAST ?*?f .



W






&&



U!' SLIMLINE ,- ^

■~ COOUNG FAN ?B^



EDGE
CONNECTORS

ALL ARE 1. 56' SPACING.



Jill EDGE CONNECTOR
PC style $2.00 aach

101?S1I.OO
22/*? EDGE CONNECTOR
SOIOerlug style (2. SO each
2S/56 EDG E CONN ECTQFI
PC slykl J2.S0a.cfl

10 lor 623.00
3? (72 EDGE CONNECTOP,
PC style 61.00 e.ch

43/66 EDGE CONNECTOR
PC .style $J SO rath

TRANSISTORS



2tir06

2N22Z2A

PN2222H

2n:s-j?

2N2004
2N2S05
MJ295S
IN305S
PMO tOK*0
TIP 121
TIP 125



1 10. SI 00
3 far Si 00
1 lot SI. 00
3 (or $1 .00

3ioiSi.no

Slorll.DO

SI so

11.00

11.60

7SC

75*



TRANSFORMERS



b 6 VO.IB tf 750 mn

Q vuu Jl 15P mi.

* j *>7ii soc- n>>.

12 vcr ? :os mj

13 V.CX g 400 n?.
12 V.CX 47 1 amp
IS V.CT. ( 2 Amp
12 vjGT. ^ * *mp

It void {I 1550 (nj
24 tf,CX f 200 mi.
24 V.CT, ft i amp
34 V.CT. ft 2 imp
24 V.C.T. ft 3 *mp
24 vC - ? 4 amp
36 VAT. ft 13& m*.



53-00

11.25
S3 00
S2 00
13.00
SJOO
S4.IS
*T.0O
S3.50
12.50
VUi
S6.75
S9.50
J11.00
13.00



WALL
TRANSFORMERS



jli plug directly

nt.O 1EDv2C

outlet




4 VDC ? 70 ma, $5 00

?3 VAC @ 500 ma. 13.50

< VDC @ 750 m* Svsrj

9 VDC @ 500 ma. $$ 00

12.5 VAC ?@ 265 m?. S3.0Q
■a VAC Ji 11 VA and

Si VAC B 1.20 VA 14,50

2-1 VAC @ 250 mo taoo
HULTI- VOLTAGE Q 500 ma

3.4ft.ft.r M,* or 12 VOC j7 50




Heavy-duty black
phenolic projecl box wilti coven ana
screws . 2Vi ' x i w x iv>:

FUSES D D

3AG (AGO SIZE
I. 1H. 2.214. 3.1. 5.6AMP
GHA SIZE C3==a

1.1.3. 4. SAMP **C=*?
5 of any ONE amperage 75(



SOUND
AND VIDEO MODULATOR
FOR T.I. COMPUTER

T.I * UMI38M Designed lot t>se with T I. cam-
puiers. Can &e used with video sources. Bum -in
A/B switch Channel 3oi a seteclion switch
Operate on 12 vdc. hook-up diagram included.



CAT* AVMOD WERE $10.00 REDUCED TO 55.00 EACH




SPECIALS

1 AMP 50 VOLT DIODES

IN4001 TAPE AND REEL
100 for 14. 50
1000 Id S3 0.0

SOLDER TAIL l.C.

SOCKETS

24 PIN 10for$2.50

100 for 522,00

10 00 lot $200.00



?SPECIAL PRICE'
TRANSISTOR

plastic transistor
PN3569TO-52 N.P.N

100 Inr IS. 00
1000 (Ol ISO. 00
LA BSE QUANTITIES

AVAILABLE



48 KEY ASSEMBLY
FOR COMPUTER OR
HOBBYIST



~aJg$feg?g&




NEWT! KEYBOARDS. OngnaBy
used on computers, these Key-
boards contain 4fl S.P.S.T.mecfi-
anical switches. Terminates to
1 5 pin conneclor. Frame 4" x 9"
CATMKP-4g $6,50 each
2 (or S1 1.00




Etri$4'sdXMie2low
no.se fan Measures

3*? square x 1 ' peep
21crm.23db.170Qrpm

SPECIAL PRICE ...t12.S0a.ch



MICRO-CASSETTE MECHANISM

Wicro-cass&!te lape transport lor

standard MC60 or MC45

micro -casseltes. 3 Vdc operation.

Contains: drive motor, belt, head,

capstan, pinch wheel and other

component. 3 MT X 2 1/4 1 * X 5/8"

CAT* MCMEC $3.00 each 10 Tor $27.50




2K 10 TURN

MULTI .TURN POT

SPECTROL
#MOD 534-7161

55.00 EACH




± 12 Vdc of 24Vdc POWER SUPPLY



DCLTRON MODEL Q0! 2/ 15-1 7

Dual plus and minus 12Vdcapen

frame power supply. Can be used as

24VrJc@ 1, 5 imp. INPUT: eilher

115 Vac PI 230 Yac

Fully regulated computer grade supply

7"Jf4V)c2*r

$12.50 each



COMPUTER E?

GRADE
CAPACITORS

2,000 mid- 200 Vdc V^
T 3/4" x 5" higft $2.00

?.400 mid. CO Vdc
1 3/8" x 3 3/4* hiflrt $2,50
3,700 mid, 50 Vdc
13/8"* 4 1/2" high $3.00
31,000 mhj, is vdc
1 3/4' x 4" high $2.5C

$0,000 mid 40 Vdc
3" )i S 3/4" high $4.50

86,000 mid. 15 vdc
3" X 3 374" high S3.M

60,000 mTd. 4Q Vdc
3"x5*high $3.50

66.000 mfd. IS Vdc
3*x33M-ltiQh S300

0�,000 mid. 30 Vdc
3" X 5 IMF hioh $3.5Q

5.500 mrtj. 30 VdC
1 3f8T x 3 T/3" high $1 .00
$,300 mfd. 30 Vdc
1 373* x 2 1/4" high $1.00
9,300 mfd. 50 Vdc
2* x 4 1/2" Wgh $1 00

13.000 mfd. 10 Vdc

1 3/B" x 2 M" hioh $1 .00
46.000 mfd. 10 Vdc

2 1/3" x 3 1/4" hkjh Jl. 00
100.000 mid. 10 Vdc

2 1,2" x 6" high $100

165,000 mfd. 6 Vdc
2 1/Tx4 NIT high $1 00



Tl SWITCHING POWER SUPPLY

Compact welkt^uiairf swiping powvr supply
designed lorjcrwe; Texas Instruments computcrr
rro.urprrieriT.

INPUT 1?5.?5xac@1nnp

OUTPUT: - l2vdc@3SOma.

- 5vdc@12amp

— 5 vdc @ 200 ma.
SIZE 4*i - x4*A"X 1 <4" hajh $5.1)0 aach




13.8 VDC REGULATED POWER SUPPLY



These ana solid scale, luliy regulaied 13.8 vdc
power 5L.ppi.ses. Both featuw 1 CC'i sa:id slate
construction, ?ust p+oiEclian. and L ED pewer
indicator. U.L I'^ted




2 ampcons-ianl, 4 amp lurgi
3pmpccmlanl, Sampaurg*



sia.oo each



D.C. CONVERTER




Designed to provice a steady z 5
vdc @ 2*0 ma rrom a oatlery
suppTy of 3.5 10 S-25 volts.
2Y?' 1 1V,.? I'Y,.'
Sl.SOaaolt



TWIST-LOCK
CONNECTOR



<=�.-.?



Same as Swttcrtcralt #12CL5M.
5 conooctor m-hne prog and chassis
mount jack. Twisl-toek siyte.
ti.SOJSET



RELAYS

10 AMP SOLID STATE



CONTROL: 3 -32 vdc '9±&\
LOAD: 140 vac 10 ampi V ._-;,*■
SIZE:2H-<V.V ^"Vj

19.50EACH 10 FOR J 90 .00

ULTRA-MINIATURE

5 VDC RELAY

Fupisu #

FE-R211NECK}05W2a wSm
High sensitivity br^ -

COIL: 120 Ohms 1x^^17

CONTACTS: 1 amp
rvtounlsm 14 tvn DIP socket
11.25 *ach 101orS10.Q0

MINIATURE

6 VDC RELAY

Aromai § RSD-6V

SuDar Small

S.PO.T nUay

GOidcoltiflii

concacis raied

1 amp -@ 30 wOc. Highly santiifm
TTL direct drive possiljie 1 20 ohm

cot.

Operate trcm 4 3-6 vdc
COIL 120oftms tlMeich

tVu^rVxVi* 10 for 513.50

13 VDC RELAY

CONTACTS: S.PN.C
I0amp@l20vac

Energize co? to
fipenconlacl...
COIL; 13 vdc 65Q ohms

SPECIAL PRICE $1.00 each

4PDT RELAY

14pmKHstyie...

3 amp contacts . . .

USED but fully

tesied $1,70 ?ach

Specify cai vonageoesrrad

Erttwr 24 vdc Of IMvflc

LARGE QUANTITIES AVAILABLE

SOCKETSFQRKH RELAY

75* each

RECHARGEABLE

NI-CAD BATTERIES



220 Vac
COOLING FAN

ROT RON n
MX77A3
hfoltin H.I
220 Vac
* 1'B* square
meral Irama ran

CAT/ CF-S20 S6.5D ea
"OlorSBOOO; 1 00 for S50O 00
QUANTITIES AVAILABLE




10 far S110.0O




SW SPEAKER

8 ohm

?rnpedance.
T u. H \ Fu" 'arrge




BQZ magnet

4 "diagonal
N&' ^^py mouni.ng csfilens.

$?.50e*ch 10 lor $20.00

SPRING LEVER
TERMINALS

Two color
coded

ter mi n ai s on a
Stytdy 2%' x
3 J v bake via
plaie.

Great for speaker enclosures or
power supclies
7W EACH 10 for $6,00



C3?



TWO WIRE

6 18/2SPT.1ll.t aiprji.oo
*'??SFT.*pr? 2to,tl.M

,; ■■; :;.,-■: .-.: i1.29aacli
THREE WIRE
6 19f3fHt t1.S0?ch

a ie/3raund IMJOeacn

7 CONDUCTOR

RIBBON CABLE




Spool ra-slnpredmorkersiDp
26 ga. stranded wire.

15.00 par 100 roll



XENON FLASH TU8E



3/4" long X 1/8" dia. Flash
lulM designed for use in
com pad camera Itasfi units
Ideal for experimenters
CAT* FLT-1 2 lor $1,00



MINIATURE TOGGLE SWITCHES

ALL ABE RATED SAMPS @ 125 VAC




AAA SIZE I.25V 5O0mAK$l.a5
AA SIZE 1. 25V SOOmAH $1.85
AA Willi solder tab 52.00

C SIZE 1.2V 1200mAM J3.50
O SIZE 1 2Y 1200mAH $3.50



UNIVERSAL CHARGER




Will charge 4-AA, C. 0. or AAA
m cads or one 9 volt ni-cad at
one time. . .
$11.00 per charger



STANDARD JUMBO
DIFFUSED T 1-3/4

RED 10 for $1.50 m

loo for sia.oo q

GREEN ID lor S3 00 i

100 lor $1700
TELLOW 10 lor $2.00

100 lor $17.00 [ I

FLASHER LED

S vote operation

red jumbo Tl4i

siz* S1 .00 each
NEW GREEN FLASHER
C-4F,TLF0-4i3 $1,00

Rl-Pni AD pumboTlnH sue
Dl PULeJMi 2ior$l L 7il

LED HOLDERS

Two piece holder ^^ Fl
rormmbcLEO *^

tOSor 63c 100 for $5, 00

CLEAfl CUPUTE
LED HOLDER
Make LED a fancy
indicator. Cleer
4 for )i qo



li\llj.l.?jl LTaVVli!
LOS ANGELES. CA STORE
905 S vermonl Ave
213 390 8000
VAN NUVS. CA STORE
6225 Sepulveda 81 vd
Ht8 997-1906



MAIL ORDERS TO

PO BOX 20405

Lot Angeles. CA 90005

TWK 5101010163 ALL ELECTRONIC
EASVLINK MBX 62887748




J VISA



'�?



TOLL FREE ORDERS ONLY QUANTITIES LIMITED

I 800 826 5432 MINIMUM QHDER $10.00

(ORDER ONLY | USA S3 .00 SHIPPING

(IN CALIFORNIA 1 BOO 258-6666) FOREIGN ORDERS
ALASKA. HAWAII. INCLUDING SUFFICIENT

OR INFORMATION SHIPPING

(213)350 8000 NOC. O.D.I CALIF RES ADD 6' ,".



D.RS.T. LIGHTED
ROCKER SWITCH
115 vac jhgmed rocker,

map mounts m

VxlWhoJ*

OrangitJens 16amp

contact

?130

MINI-PUSHBUTTON

S PS.T. mOmenlary
normally ppan
14' bushing
Red buiton
35t*-jch
10 lor 13.00



SNAP ACTION
SWITCH



Cherry bJkT. #E-21 . NO, orN.C,
0.1A contaclt. SwlabJa lor alarms

and Other lOweneray circuits
y\v lewer.

45CEACH 10 FOR J4.20

ROTARY ACTION
MICRO

OMRON ?C-5G3-C41
Clockwise .cticn micro
used in com operafed
mocha n isms and low torque
operations.

HATE0:5amps@ 125Vac.
$1.25 each 10 far $11.00

LARGE QUANTITIES AVAILABLE




CIRCLE 107 ON FREE INFORMATION CARD



>

-<

OS

00
CD



99



THE BEST PLACE [o BUY, SELL or
TRADE NEW uid USED EQUIPMENT

NUTS & VOLTS MAGAZINE

BOX llll-E ■ PLACENTIA. CA ?2670

(714)631-7721

join Thousands ol Readers hjaitonwide

Every Manih

ONE YEAR U.S. SUBSCRIPTIONS

SIO.M - 3rd Clisi ■ 515. M - lit Class

fijb 5JS M . Lifetime - 3rd Clut L3



HAH SEAR
COHFUTEEIS
TOrTWMI
SCAKMEAl - OfTKS
TEST EQLMPMEtar
HPCKOWAVE



ait, in vi'.iai
wew rw-u;,:. :r.

COMEOHEriTi - KITS

Arrriguc elect.

PUBLICATIONS

rvAha - SIKVbCEt



BUILD this five digit panel meter and square wave
generator including an ohms, capacitance and fre-
quency meter. Detailed instructions $2.50 refunda-
ble plus SO cents. BAGNALL ELECTRONICS, 179
May, Fairfield, CT 06430. __

CIRCUIT BOARDS guaranteed lowest quotes. Sin-
gle and Double Sided Boards. Prototypes through
large production quantities. Mail specifications tor
quotes. HOBBYISTS: Print your own circuit board.
Kits of all sizes, low prices. Basic Kit. $3.00, mate-
rials for two 3"x4" boards (included), or SASE lor
catalog T.O.R.C.C.C. ELECTRONICS, Box 47148,
Chicago, II 60647, (312) 342-9171.

LOW cost modern, easy to build, 300 baud direct
connect, simple interface. $5. for plans. OMNISTAR
DESIGNS, Box 398, Columbus, NE 68601.

METAL detector, sensitive, easy to build. Plans
$5.00, POWELL, 1162 June Drive, Xenia, OH
45385.

FREE electronic tool kit, with membership in Elec-
tronic Project Club. Info and catalog $2.00. AEWS,
PO Box 746, Delvalle, TX 78617.

KEYPAD Control: Centralized digital control of all
automobile electrical functions. Detailed sche-
matics. ; instructions. S5.00. BAYSIDE ELEC-
TRONICS Box 71 , Patuxent River, MD 20670.



CABLE-TV

DEALERS wanted: Channel 2,3, and 4 notch fil-
ters. Money back guarantee. Send $15.00 for
sample and quantity price list. Specify channel(s).
GARY KURTZ, Box 291394. Davie, FL 33329.



WORLDS BEST CHANNEL 3 NOTCH FILTER.
$39.95. (DEALER INQUIRES INVITED).
CROSLEY(A), BOX 640, Champ.a.n, NY 12919.

SB3 DESCRAMBLER PARTS to construct project
in Feb/84 Radio Electronics. $49.95 (Dealer inquir-
es invited). CROSLEY, Box 840, Champlain, NY
12919.

NEW JERROLD STARCOM-CS 60 channel, wire-
less, remote control cable converter. Volume and
"commercial killer" mute control. Programmable
time switch turns TV orv'off and can change chan-
nel. Programmable favorite channel scan. Instant
channel recall. Automatic fine tuning with manual
overide. Video and audio outputs. Works with all
descramblers. 1 year warranty. $169. Dealers want-
ed. CROSLEY, Box 840, Champlain, NY 12919
(518) 561-8700.



VIDEO SPECIAL EFFECT PLANS



Excm-tgi COLOR Sp*ciii Effect ui*d m Mum
y deo: - worki with my i ?k cirrwra or VCfl
- - t *i>*iis , a to bvild. w*y 1o u? ■ S*c.l1 chK< c
iVtDMrV orrjoi- 1w *V* pltii ■■? ihipping Kid
handling for cgmplaH pacfcjge ^ndurdKig sc.t-
mldc.PGB artwork, th*a?y4 iMtruCLiOM |Oh ::
R?. add 1 .65 ailes Ituc) or and SASE larFrw
BfXhU ■ e to



VIDEO EFFECTS
U9b9 BHECKSVrLLE RQA



WANTED




Aclum) BJW phQttr
Ot GQtor EffacJ



SPEAKER REPAIR



SPEAKER reconing-radio, hi-fi. musical instru-
ment. All work guaranteed. SSI, 1925 Charrwell, Ft.
Wayne, IN 46816. (219) 42-MUSIC.

ELECTRONIC COMPONENTS

ELECTRONIC COMPONENTS— Resistors, any
value/qua ntity [Mini m u m 20/va I u e). 1 1 A watt $ . 01 1/2
watt $.02 - $1.25 shipping. Quantity discounts,
1,000-. Send wattage(s), value(s) Quantity(s) and
remitance. Capacitors - 50V Ceramic Disk, all val-
ues $.10@, minimum order $1.00 - $1.25 shipping.
T.O.R.C.C.C. ELECTRONICS, Box 47148, Chi-
cago, IL 60647. (312) 342-9171.



INVENTORS! AIM wants— ideas, inventions, new
products, improvements on existing products. We
present ideas to manufacturers. Confidentiality
guaranteed. Call toll free 1-800-225-5800 for infor-
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TELETEXT DECODER



continued from page 70



Once the page appears correctly, alternate
between TV and teletext modes several
times, making certain that the page comes
up properly each time.

If you have trouble getting a clear im-
age and you have a static-and snow-free
TV image, adjust the module's oscillator
so that it will lock onto the incoming data.
This is done by adjusting the trimmer ca-
pacitor near the crystal on the module.
The module coil and that trimmer may
have to be adjusted in concert to get a clear
teletext image; go slowly, and allow the
page time to clear between adjustments.

When you have a stable teletext image,
adjust the trimmer capacitor C38 on the
PC board until the color appears in the
teletext page. Don't worry about color
values; adjust for clear, even colors across
the display. Then adjust the chroma bal-
ance control R52, near IC4 (MC1377),
until the colors are acceptable. Again,
some cross adjustment of C38 and R52
may be necessary to obtain the best color.

Using the decoder

Using the DSE Teletext is as easy as
turning it on — even a child can use it with-
out more than brief instruction. How you




Jay mode and



MIX

CANCEL

TOP

BOT

FULL

REVEAL

HOLD

TIME ON/TIME OFF



TABLE 1— REMOTE CONTROL FUNCTIONS
Function

Enters desired page number

Switches decoder to teletexf mode

Switches decoder Jo regular TV display i

clears teletext settings

Superimposes teletext display over regular TV

image

Returns display to regular TV image without

interrupting teletext operation

Expands top 12 lines of teletext display to fill

screen

Expands bottom 12 lines of teletext display to fill

screen

Restores teletext display to full 24 lines

Causes hidden portion of display to appear

Causes page in RAM to be held despite changes

in broadcast signal.

For timed-page and rolling-page systems only.



connect it into your video system depends
on whether you want to be able to bypass
the decoder; if it cannot be bypassed, it
will have to be on whenever you watch
TV.

The decoder can be used in three
modes: teletext, mix, and newsflash. If
you simply want to scan through the pages
of a teletext service, press rr to enter
teletext mode and select the page you want
to see by simply entering its number. If
you want to view the pages and monitor
the TV image at the same time (during a
commercial, for example, or while check-



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Games with required 2B pin connector and
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CIRCLE 72 ON FREE INFORMATION CARD



ing sports scores in the middle of a game),
press mix and the text will appear in white
over the TV image. Finally, if you just
want to watch TV, but want to be alert for
news, you can set the decoder to a teletext
service's newsflash page in mix mode.

The newsflash page is normally held
blank, so that the TV image will remain
undisturbed in the mix mode. If a news
story breaks, the service inserts one or
two lines of text at the bottom of the page,
usually a brief headline and the page to
see for details.

When the decoder is switched from TV
to teletext mode, it will always come up
on page 100, which has been chosen as the
universal index page for World System
Teletext. From that page you can go to any
other, be it an index or a feature page,
simply by entering that page number.
When the page comes around in the loop,
the decoder will store it in RAM and dis-
play it on the screen.

If you want to go to another magazine
broadcast within the same VBI, simply
enter a page that is within that magazine's
loop. On WTBS and SPN, Electro's title
page will always come up on page 100,
and any page between 100 and 199 is with-
in Etectra's. loop. If you want C ablet ext,
enter any page number between 201 and
212, and the decoder will enter
Cabletext\ loop and present the selected
page from that magazine.

When you select a new page, the pre-
vious page remains in RAM and on the
screen until the new one appears — there is
no blank screen time. The wait for a new
page can be 15 to 20 seconds, but is about
4 seconds on the average. If you don't
want to wait, or if you want to check the
TV image without disturbing the teletext's
operation, press cancel. That will return
the display to regular TV, without inter-
rupting the decoder's operation. At your
convenience, you can return to teletext or
mix mode, right where you left off. All of
the remaining decoder commands are
summarized in Table 1 .

Now, get started and enjoy your de-
coder! R-E



102




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1-95


4.032


1.95


5.0


1.95


5.0636


1.35


8.0


1.95


6.144


1.95


6.5536


1.95


3.0


1.95


10.0


1.96


1 0.738635


1.95


12.0


1.95


14.31813


1.95


15.0


1.95


16.0


1.96


17.430


1,95


18


1.95


18.432


1.95


20 .0


1.95


22.1184


1.95


24.0


1.95


32.0


1.95


CRYSTAL


OSCILLATORS


LOMHi


5.95


1.8432


5.95


2.0


5.95


2.4576


5.95


2.5


4.95


4.0


4.95


5.0688


4.95


6.0


4.95


6.1 44


4.95


8.0


4.95


10.0


4 95


12.0


4.95


12.430


4.95


15.0


4.95


16.0


4.95


18.432


4 95


20.0


4.95


L 24.0


4.95



CLOCK
CIRCUITS

MM 5369 1.95

MM 5 369- EST 1.95
MM5S167 12.95
MM5S174 11.95
. MSM5S32 2.95 .



SOUND CHIPS



TMS99531

TM53SS32

LI LN 2003

3242

3341

MC3470

MC3430

MC34S7

11C90

2513-001 UP

AV5 2376



7.S5
4.95
1.95
8.95
2.95

13.96
6.95

11.95



i A V5- 3600 PRO 11.95





74LS00




74LS00


.16


74LS165


.66


74LS01


-18


74LS166


.95


74LS02


.17


74LS169


95


74LS03


.18


74LS173


49


74LS04


,16


74LS174


,39


74LS05


-18


74LS175


.39


74LS08


.18


74LS191


.49


74LS0S


.18


74LS192


69


74LS10


.16


74LS193


.69


74LS11


.22


74LS194


.69


74LS12


.22


74LS195


.69


74LS13


.26


74L5196


.59


74LS14


.39


74LS197


59


74LS15


.26


74LS221


.59


74LS20


.17


74LS240


.69


74LS21


.22


74LS241


.69


74LS22


32


74LS242


.69


741S27


.23


74LS243


.69


74LS28


.26


74LS244


.59


74L530


.17


74LS245


.79


74LS32


.13


74LS251


.49


74LS33


.23


74LS253


.49


74L937


.26


74LS256


1.79


74LS38


.26


74L6257


39


74LS42


.33


74LS258


.49


74LS47


.53


74LS259


1.29


74LS4B


.63


74LS260


.49


74L551


.17


74LS266


.39


74LS73


.29


74LS273


.79


74LS74


.24


74LS279


.39


74LS75


.29


74LS2S0


1.98


74L576


.23


74LS283


.59


74LS83


.49


74LS290


.89


74LSS5


.49


74L8293


.89


74LS86


.22


74LS299


1.49


74LS90


.39


74LS322


3.95


74LS92


.49


74LS323


2.49


74LS93


.39


74LS364


1.95


74LS95


.49


74LS365


.33


74LS107


.34


74LS367


.39


74LS109


.36


74LS363


.39


74LS112


.29


74LS373


.79


74LS122


.45


74LS3/4


.79


74LS123


.49


74LS375


.95


74LS124


2.75


74LS377


.79


74LS125


.39


74LS376


1 13


74LS126


.39


74LS390


1.19


74LS132


.39


74LS333


,79


74LS133


.49


74LS541


1.49


74LS136


.39


74LS524


1.95


74LS138


.39


74LS640


.99


74LS139


.39


74LS645


.99


74LS145


.99


74LS669


1.29


74LS147


.99


74LS670


.89


74LS148


.99


7419682


3.20


74LS151


.39


74LS683


3.20


74LS153


39


74LS684


3.20


74LS154


1.49


74L5688


2.40


74LS155


.59


74LS783 22.95


74LS1S6


.49


81LS95


1.49


74LS157


.35


S1LS96


1.49


74LS15B


.29


81LS97


1.49


74LS160


.29


S1LS98


1,49


74LS161


.39


25LS2521 2.80


74L9162


.49


25 LS 2569 2.80


74L9163


.39


26LS31


1,95


74LS164


.49


2SL532


1,95 ,



Model


Tims,


Capacity
Chip


Intensity
(uW/Cm 1 )


Unit
Price


PE-14


NO


9


8,000


5 S 3.00


PE-14T


VES


9


8.000


5119.00


PE-24T


VES


12


9,600


1175.00





HIGH SPEED CMOS

A new family of high speed CMOS logic featuring
1rifi speed of low power Schottky {8ns typical gate
propagation delnyf, combined wrth the advantages of
CMOS: very low powcf consumption, supefiof noise
ijnm,,jmty. and improved oulpur dnve.



74HC; Operate at CMOS logic levels and are ideal

fot new. all-CMOS designs.



74HC00

74HC02

74HC04

74HC08

74HC10

74HC14

74HC20

74HC27

74HC30

74HC32

70HC51

74HC74

74HC95

74HC86

74HC33

74HC107

74HC109

74HC112

74HC125

74HC132

74HC133

74HC13B

74HC139



74HCT: Difect. drop,
and can be intermixed with



74HC143

74HC151

74HC154

74HC157

74HC158

74HC163

74HC176

74HC240

74HC244

74HC245

74HC2S7

74HC259

74HC273

74HC299

74HC36S

74HC373

74HC374

74HC390

74HC393

74HC4017

74HC4020

74KC4049

74HC4050



replacements for LS TTL
74LS ■-' the same circurt.



74HCT00

74HCT02

74HCT04

74HCT08

74HCT10

74HCT11

74HCT27

74HCT30

74HCT32

74HCT74

74HCT7S

74HCT138

74HCT139

74HCT154

74HCT157

74HCT1 58

74KCT161

74HCT164



.69
.69
,79
.85
.95
1.15
1.15
2.99
99
.99
1.29
1.39



74HCT165

74HCT174

74HCT193

74HCT1S4

74HCT240

74HCT241

74MCT244

74HCT245

74HCT257

74HCT259

74HCT273

74HCT3G7

74HCT379

74HCT374

74HCT393

74HCT4017

74HCT4040

74MCT4060



3.05
1.09
1.39
1.19
2.18
2.19
2.19
2.19
.99
1.59
2 09
1.09
2.49
2.49
1.59
2.19
1.53
1.49



VISIT OUR RETAIL STORE LOCATED AT 1256 SOUTH BASCOM AVENUE IN SAN JOSE

. HOURS: M-W-F, 9-5 TU-TH,9-9 SAT, 10-3

l\/llCrOCl(?\/IC6S PLEASE USE YOUR CUSTOMER NUMBER WHEN ORDERING
_ _ . __^__ ? BM ? "'"'">"" ordtr IHUO, For shipping and handling include S250 lor UPS

_ 1224 S. Bascorn Avenue, San Jose, CA 95128 \^^^^^-?LStS^^lS^SSSS.S^S&

800-538-5000 ? 800-662-6279 (CA) ? (408) 995-5430 ^^^^'^^^t^Z^T^^^^^Z^

FAX (408) 275-841 5 ? Telex 1 71 -1 1 *?2SZ?JSE!%?3?? X+SSlSlZ** "" ,, " H " '"? *

? COPYRIGHT 1986 JDR MICRODEVICES
THE JDR MICRODEVICES LOGO IS A REGISTERED TRADEMARK OF JDH MICRODEVICES JDH INSTRUMENTS AND JDR MICRODEVICES ARE TRADEMARKS OF JDR MICRODEVICES
IBM IS A TRAOEMARK OF INTERNATIONAL 8USINESS MACHINES. APPLE LS A TRADEMARK OF APPLE COMPUTER



CIRCLE 1 13 ON FREE INFORMATION CARD



l "iu 1 , ii j | . ' i| y ■ ?. ' "7i i | i



umc? >um>nc iiareo. f nces ant subjoci lo change ynrhoot nonce We are not
rMponsiBte tor typographical mors, we rMenre the right lo limit ouantltles and to
suosliltile manutacEurer. AH merchandise subfeel to prior sale



PARTIAL LISTING ONLY — CALL FOR A FREE CATALOG





CMOS






7400/9000




4001


-19


14419


4.95


7400


.19


74147


2-49


4011


.19


14433


14.95


7402


.19


74148


1.20


4012


.25


4503


49


7404


.19


74150


1.35


4013


.35


4511


69


7+06


.29


74151


.55


4015


.29


4516


.79


7407


.29


74153


.55


401E


.29


4513


.85


7408


.24


74154


1.48


4017


49


4522


.79


7110


.19


74155


.75


4018


69


4526


.79


7411


.25


74157


.55


4020


.59


4527


1.95


7414


.49


74159


1.65


4021


.69


4518


.79


7416


.25


74161


.69


4024


.49


4529


2.95


7417


25


74163


.69


4025


.25


4532


1.95


7420


.19


74164


.85


4027


.39


45 38


.95


7423


.29


74185


.85


402B


65


4541


1 JO


7430


.19


74166


1.00


4035


69


4553


5.79


7432


.29


74175


.89


■1040


.69


45B5


.75


7438


.29


74177


.75


4041


.75


4702


12.95


7442


.49


74178


1.15


4042


.59


7-1 COO


.29


7445


.69


74181


Z.25


4043


.65


74C14


.59


7447


89


74182


.75


4044


.69


74C74


.59


7470


.35


74184


2.00


4045


1 98


74C83


1 95


7473


.34


74191


1.15


4046


69


74C85


1.49


7474


.33


74192


.79


4047


.59


74C35


.99


7475


.45


74194


.85


4049


3a


74C150


5.75


7476


.35


74196


.79


4050


.29


74C151


2.25


7483


.60


74197


.75


40S1


.69


74C161


.99


7485


.59


7-1199


1.35


4052


.69


74C163


.99


7486


.35


74221


1.35


4053


69


J4C164


1,39


7489


2.15


74246


1-35


4056


2.19


74C192


1.49


7490


.39


74247


1.25


■1060


.69


74C133


1.49


7492


SO


7424S


1.S5


4066


.29


74C221


1.75


7493


.35


74249


1.95


4069


.19


74C240


1.89


7495


.55


74251


.75


4076


.59


74C244


1.89


7497


2.75


74285


1.35


4077


29


74C374


1.99


741 00


2.29


74273


1.95


4031


.22


74C805 10.95


74121


.29


7427B


3.11


4085


.79


74C811


8.95


74123


.49


74367


.65


4036


.99


74C917


8.95


74125


.45


7436S


.65


40S3


.49


74C922


4.49


74141


.65


9388


3.95


4094


249


74C923


4.95


74143


5.95


9602


1,60


14411


3.95


74CS26


7.95


74144


2.9S


9637


2.95


14412


6.95


30C37


.95


74145


.60


96S02


1.95 I





74SO0




74S00


.29


74S163


1.29


74S02


.29


74S168


3.95


74S03


.29


74S174


.79


74S04


.29


74S175


73


74S05


.29


74S18S


1.95


74S0S


.35


745189


1.95


74510


.29


74S195


1.49


74815


.35


74S1 96


1.49


74S30


.29


74S197


1.49


74S32


.35


74 52 26


3.99


74S37


.69


745240


1,48


. 74S3S


,69


745241


1-48


74S74


.49


745244


1.48


74S85


.95


74S2S7


.79


74S86


.35


74S2S3


79


7461 12


.50


74S25S


.95


| 746 124


2.75


74S2S0


1.95


749138


.79


745287


1 60


74S140


.55


745288


1.69


74S151


.79


74S299


2.95


74S153


.79


74S373


1.69


74S157


.79


74S374


1.69


745158


.95


74S471


4.95


1 745161


1.29


74S671


2.95 J



[DATA ACQ


INTERFACE]


ADCOBOO 1S.55


8T26


1.28


ADC0S04 3.49


8T28


1,29


ADC0809 4.49


8T95


.89


ADC0816 14.95


8T96


.89


ADC0H17 9.95


8T97


.59


ADC0S31 8.95


BT98


.69


DAC0800 4.49


0MS131


2.95


DAC0806 1.95


DPE304


2.29


DACOBOS 2.95


DSSE33


2.25


DAC1D20 8.25


DSS835


1.99


DAC1022 5.95


D 58 8 36


.99


1MC140SLS 2.95


058837


1.65 J



EDfiECARD CONNECTORS ]


too


PIN


ST


SI 00


.125


3.95


IOC


PIN


WW


S-100


.125


4.95


62


PIN


5T


IBM PC


,100


1.95


50


PIN


5T


APPLE


.100


2.95


44


PIN


ST


STD


156


1.95


l44


PIN WW


STD


.155


4.95 1



36 PEN CENTRONICS

MALE
IDCEN36 H IB BON CABLE
CEN36 SOLDER CUP
FEMALE

IDCEN3G F RIBBON CABLE
l CEN36PC HT ANGLE PC MOUNT


5 95
4,95

7.95

4.95



' INTERSIL


ICL7106 9.9S


ICL7107 12.95


ICL7660 2.95


1CL8038 4.95


ICM7207A 5.95


[ICM720S 15.95



VOLTAGE
REGULATORS

TO -220 CASE

7805T .49 7905T 59

7808T .49 7906T .59

781 2T .49 791 2T 59

7815T 49 791ST .59

TO-3 CASE

7905K 1.39 7905K 1.49

7812K 1.39 7912K 1.49

TO- 9 2 CASE
78 LOS .49 79L05 .69
78L12 .49 79L12 .69

OTHER VOLTAGE REGS
LM323K5V 3A TO- 3' 4,79
LM338KAq 5A TO-3 3,95
78H05K5V 54 TO-3 7.95
78H12K I2V5A TO-3
. 78P05K 5V IDA TO 3 14.95 ,



IC SOCKETS




199


100


I 8 FIN ST .11


.10


14 PIN ST .11


09


16 PIN ST .12


.10


18 PIN ST -IS


.13


20 PIN ST .IS


.15


22 PIN ST .15


.12


24 PIN ST ,20


.16


28 PIN ST .22


.16


40 PIN ST .30


.22


64 PIN ST 1.95


1.49


ST^SOLDERTAIL




S PIN WW .58


,49


14 PIN WW .69


.52


16 PIN WW .69


58


IS PIN WW .99


.90


20 PIN WW 1.09


98


22 PIN WW 1.39


1.2S


24 PIN WW 1.49


1,35


23 PIN WW 1.69


1 49


40 PIN WW 1.99


1.80


. WW WIREWRAP




16 PIN IIF 4.95


CALL


24 PIN ZIF 5.95


CALL


28 PIN ZIF 6.95


CALL


40 PIN ZIF 3.95


CALL


ZIF TEXTOOL




1 IZEHO INSERTION FORCE]





LINEAR




TL066


.99


LM733


.38


TL071


.69


LM741


.23


TL072


1.09


LM747


.69


TL074


1.95


LM748


.59


IL051


.59


MCI 330


1.69


TL0S2


.99


MCI 350


1.19


TL084


1.49


MCI 372


6.95


LM301


.34


LM1414


1.59


LM309K


1.25


LM145B


.49


LM311


.59


LM1493


.43


LM311H


.89


LM1489


43


LM317K


3.49


LM1436


85


LIW1317T


.95


LM1812


8.25


LM313


1.49


LM18B9


1.95


LM319


1.25


ULN20O3


.79


LM320 u


?7900


XR2206


3.75


LM322


1.65


XR2211


2.95


LM323K


4.73


XR2Z40


1.95


LM324


.49


MPQ2907


1.95


LM331


3 35


LM2317


1.95


IM.fi'.


1.19


CA3046


89


LM335


1.40


C A3 OBI


99


LM336


1.75


CA3082


.39


LM337K


3.35


C A3 086


-SO


LM33SK


3 35


CA3Q89


1.95


LM333


.59


CA3130E


.39


LM340 1B07SOO


CA3146


1.29


LM350T


4.60


CA3160


1.19 1


LF353


.59


MC3470


1.95 1


LF356


.99


NIC 3480


SJS5 1


LF357


.99


MC3487


2.95 1


LM35S


.59


LIVI3900


49 1


LM3B0


.89


LM3909


.98 1


LM3S3


1.95


LM3911


2.25 1


LM386


.89


LM3314


2.35


LIU 393


.45


MC4024


3.49 1


LM394H


4.60


MC4044


3.99 1


TL494


4.20


RC4136


1.25 1


TL497


3.25


RC45S8


.59 1


NE555


-29


LW11 3600


1.49


NE556


.49


75107


1.49 1


NE553


1.29


75110


1.95 1


NE564


1.95


75150


1.9S 1


LM565


.95


75154


1.95 1


LM566


1.49


75188


1.25 1


LM567


.79


751B9


125 1


IVE570


2.95


75-151


.39 1


NES90


2.50


75452


39 1


NE592


.93


75453


.39 1


LNI710


.75


75477


1.23 1


LM723


.49


75492


-73 1


I H = TQ5CAN, K


TO-3. T=TO-220 J





DIP Ct


INHECTORS














DESCRIPTION


ORDER BY


CONTACTS


8


14


16


18


20


22


24


28


40


HIGH RELIABILITY TOOLED
ST IC SOCKETS


AUGATmST


.62


.79


.39


1.03


1.29


1.39


1.49


1.69


2.49


HIGH RELIABILITY TOOLED
WW IC SOCKETS


AUGATiiWW


1.30


1.80


2.10


2.40


2.50


2.90


3.15


3.70


5.40


COMPONENT CARRIES
[DIPHEADEHS]


ICCxx


.43


.53


.63


.99


.39


.99


.39


1.09


1.49


RIBBON CABLE
DIP PLUGS (IOCI


IDPttx


_


.95


.95


~


-


...


1.75


...


2.95



l~^ p=z^




FOR ORDERING INSTRUCTIONS SEE O-SiJBMlNIATUFIf; BELOW



T"n m 1 1

AUG AT 24 ST





D-S


UBMINIATURE










DESCRIPTION


ORDER BY


CONTACTS


9


IS


13


25


37


50


SOLDER CUP


MALE


DBxkP


.82


90


1.25


1.25


1.30


3.48


FEMALE


OB?x5


.95


115


1.50


1.50


2.35


4 32


RIGHT ANGLE
PC SOLDER


MALE


DBxxPR


1.20


1 43




1.95


2.65




FEMALE


OB**SR


1.25


1.55


—


2.00


2.79




WIRE WRAP


MALE


DBxxPWW


1.69


2 56


—


3.ao


5.60




FEMALE


DBxxSWW


2.76


4.27




6.S4


9.95




IDC
RIBBON CABLE


MALE


IDBxxP


2.70


2 95


—


3.33


5.70




FEMALE


IDBxaS


2.92


3.20




4.33


G.76


?


HOODS


METAL


MHOODxx


1.25


1.25


1.30


1-30


...


...


GBEY


HOODxh


.65


.65


.?


.65


.75


.95





5 1 DB37S



ORDERING INSTRUCTIONS: INSERT the number of contacts IN THE POSITION

MARKED In" OF THE -OflO?H BY" PART NUMBE R LISTED.

EXAMPLE: A 15 PIN RIGHT ANGLE MALE PC SOLDER WOULD BE DBISFfl



MOUNTING HARDWARES 1.00




IDC CONNECTORS



DESCRIPTION


ORDER BY


CONTACTS


10


20


26


34


40


50


SOLDER HEADER


IDH?*S


.82


1.29


1.68


Z.ZO


2.58


324


RIGHT ANGLE SOLDER HEADER


IDHxxSR


.65


1 35


1 76


Z.31


2.72


3.39


WW HEADER


IOH??W


1.86


2.98


3.34


4.50


528


6.63


RIGHT ANGLE WW HEADER


IDH?*WR


2.05


3 2$ 4 23


4.45


4.80


7.30


RIBBON HEADER SOCKET


IDS"


79


.99 139


1.59


1 99


2.25


RIBBON HEADER


IDNIsi




S.50


6.25


7.00


7,50


8.50


RIBBON EDGE CARD


IDExx


1.75


2 25


2.65


2.75


3.SO


3 35





FOR ORDERING INSTRUCTIONS SEE D-SUBMIN1A TURE ABOVE



DIODES/0PT0/TRANSISTORS


1N751




.25


4N26


.69


1N753




-25


4N27


69


1N414S


75


1.00


4N28


.69


1N4004


10


1.00


4N33


.89


IN 5402




.25


4N37


1.19


KBPC'4




.55


MCT-2


.53


KBUSA




.95


MCT-6


1.23


M DA 990 2




.35


TIL-111


.93


N2222




25


2N3306


.10


PN2222




.10


2N4401


-25


2N2905




.50


2N4402


.25


2N2907




.25


2N4403


.25


2N3055




.79


2N604S


1,75


L 2N3904




.10


TIP31


.49 J



FND-357[359I

FND-5001503)

FND-507I510I

MAN-72

MAN-74

MAN-8940

L-313
HP5082-7760
TIL-311
HP 508 2-7340



LED DISPLAYS

COM CATHODE
COM CATHODE
COM ANODE
COM ANODE
COM CATHODE
COM CATHODE
COM CATHODE
COM CATHODE
4x7 HEX W/ LOGIC
4x7 HEX W LOGIC



DIFFUSED LEDS



1-93



JUMBO RED


T1V,


.10


JL>M BO GREEN


T1?


.14


JUMBO YELLOW


T1V.


.14


MOUNTING HDW


T1W


.10


MINI RED


T1


.10



SWITCHES

MINI TOGGLE ON -ON
DPDT MINI TOGGLE ON ON

| DPDT MINI TOGGLE ON OFF ON

SPST MINI -PUSHBUTTON NO.

SPST MINI -PUSHBUTTON N C

SPST TOGGLE ON-OFF

BCD OUTPUT TO POSITION 6 PIN D1P



DIP SWITCHES



4 POSITION

5 POSITION
i 6 POSITION



,S5 7 POSITION .95

-90 S POSITION .95

.90 10 POSITION 1.29 ;



HARD ID FIND
"SNAPABLE" HEADERS

CAN BE SNAPPED APART TO

MAKE ANY SIZE HEADEH.

ALL WITH .1" CENTERS

1x40 STRAIGHT LEAD .93

1x40 RIGHT ANGLE 1.43

2x40 STRAIGHT LEAD

.2x40 HIGHT ANGLE



SHORTING
BLOCKS



It was a pleasure to place an order with your

people. I found the response pleasant and
helpful and the answers prompt and oorreot. The
delivery on my moat recent order was fast,
correct and well packed . lalreadyhadfaithin
the quality since my family has been using some
of your products for several years with no
pr oh lems.

Sincerely, J.D. Hattaway

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SPACED

ATI"

CENTERS



.


tIBBON CAB


LE


CONTACTS


SINGLE COLOH


COLOR CODED


!'


10'


r


10'


10


.IB


1.80


JO


2.75


16


3?


250


.*S


4.40


20


.30


3.20


SO


5 50


25


.46


4.00


.75


6.35


26


.46


4.10


.73


7.15


34


.61


5.40


1.07


9.35


40


.72


6.40


1.20


11.00


50


.33


7.S0


1.50


13.25



order toll free 800-538-5000 800-662-6279 <ca>



BARGAIN HUNTERS CORNER

FRANKMpCE-10

DISK DRIVE FOR APPLE II

* RELIABLE, DIRECT DRIVE MECHANISM MADE FOR
FRANKLIN BY MITAC, A WORLD LEADER IN FDDs
FOR APPLE -

| * 100% COMPATIBLE WITH APPLE II. lit, AND lie; USE
W/STANDAHD APPLE CONTROLLER OR OPTIONAL
S49.95 CONTROLLER Bk -"Cii

* FULL H EIGHTBE IGE EN CLOSUR E MATCHES APPLE:
BAKED ENAMEL FINISH RESISTS SCRATCHES

* SHIELDED CABLE WITH GROUNDING LUG FOR
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R WARRANTY




HURRY — QUANTITIES ARE LIMITED!
SPECIALS END 4/30/86



PAGE WIDE WRAP WIRE

PRECUT ASSORTMENT

IN ASSORTED COLORS S27.50

1Mm:5.S". 6.0", 6.5". 7.0"
250OO; 2.5", 4.5", 5.0"
SOOeo: 3.0", 3.5", 4.0"



100 feet S4.30
500 feet 313 25



260 foot S7.25
1000foetS21.95



Please specify color;

Blue, Black, Yellow or Red



EMI FILTER

* MANUFACTURED
BVCORCOM

* LOW COST

* FITS LC-HP BELOW
■ 6 AMP 120/240 VQLT "

8 FOOT LINE CORDS

LC-2 2 CONDUCTOR J

LC3 2 CONDUCTOR

LC HP 3 CONDUCTOR W/STD

FEMALE SOCKET 1.

MUFFIN FANS



WIRE WRAP PROTOTYPE CARDS

FR-4 EPOXY GLASS LAMINATE

WITH GOLD-PLATED EDGE-CARD FINGERS




IBMPR2 .___

IBM

BOTH CARDS HAVE SILK SCflEENEO LEGENDS

AND INCLUDES MOUNTING BRACKET

IBM-PR1 W[TH -5V AND GROUND PLANE .... 327.95

IBM-PR2 AS AGOVEWITH DECODING LAYOUT S29.95

S-100

P1O0-1 BARE . NO FOIL PADS $15.15

P100-2 HORIZONTAL BUS S21.80

P10O-3 VERTICAL BUS S21.S0

P100-4 SINGLE FOIL PADS PER HOLE S22.75

APPLE

P50O-1 BARE - NO FOIL PADS *15.1 5

P500-3 HORIZONTAL BUS *22-7&

P5D0-4 SINGLE FOIL PADS PER HOLE ;.■...', 521.80

L 70SQ-45 FOR APPLE IId AUX SLOT $30.00 ,



SOCKET-WRAP



* SLIPS OVER WIRE WRAP PINS

■ IDENTIFIES PIN NUMBERS ON WRAP
SIDE OF BOARD

? CAN WRITE ON PLASTIC; SUCH AS IC s
PINS PARTS PCK. OF PRICE

S IDWRAP OS 10 1.95



14


IDWRAP 14


10


1.95


16


IDWRAP 16


10


1.95


16


IDWRAP 16


6


1.95


20


IDWRAP 20


6


1.95


22


IDWRAP 22


5


1.95


24


IDWRAP 24


5


1.9S


211


IDWRAP 23


5


1.95


40


IDWRAP 40


5


1.95



PLEASE ORDER BY NUMBER OF
PACKAGES iPCK OF r






CAPACITORS








TANTALUM






1-Oluf


15V


.35


-47ul


35V


.45


6.8


15V


.70


1.D


35V


.45


10


ISV


.60


2.2


35V


.65


22


15V


1.35


4.7


35V


35


.22


35V


.40


10


35V


1.00






DISC






10pl


50V


.05


630


50V


.05


22


50V


.05


ooiui


SOV


.05


27


50V


.05


.0022


50V


.05


33


50V


.05


.005


50V


-05


47


SOV


.05


.01


50V


.07


6B


50V


.05


.02


50V


.07


100


50V


.05


.05


50V


,07


220


SOV


.05


.1


12V


.10


560


SOV


.05


.1


50V


.12




MONOLITHIC






.OliJl


50V


.14


M


SOV


.18


.047u<


50V


.15


,47pf


50V


.25




ELECTROLYTIC




RADIAL




AXIAL




V*


25V


.14


V


50V


.14


2.2


35V


.15


10


50V


.16


4.7


50V


.15


22


16V


.14


10


50V


,15


47


SOV


.20


47


35V


IS


100


35V


.25


100


16V


.18


220


25V


.30


220


35V


.20


470


SOV


.50


470


25V


.30


1000


16V


.60


3200


16V


.70


2200


16V


.70


4700


25V


1.45


4700


16V


1.25


[computer grade


44,0GO?rf


30V


3.95]



FRAME STYLE
TRANSFORMERS



25 PIH D-SUBziF^=^y
GENDER
CHANGERS

$7.95

DATARASEEPROM ERASER

- ERASES TWO EPROMS IN 10 MINUTES
. COM PACT- NO DRAWER
■ THIN METAL SHUTTER

PREVENTS UV LIGHT

FROM ESCAPING



'/a WATT RESISTORS

5% CARBON FILM ALL STANDARD VALUES
FROM 1 OHM TO 10 MEG- OHM

ameuota .05 tOO PCSaamo value ,02

seTT**** 025 1000 PCS same value .015 ,



SWITCHING POWER SUPPLIES






RESISTOR NETWORKS




SIP


10 PIN


9 RESISTOR


.69


SIP


8 PIN


7 RESISTOR


,59


DIP


16 PIN


8 RESISTOR


1.09


DIP


16 PIN


15 RESISTOR


1.09


DIP


14 PIN


7 RESISTOR


.99


DIP


14 PIN


13 RESISTOR


.99 J



SPECIALS ON BYPASS CAPACITORS

.01 /A CERAMIC DISC 10O/S5.0O

.01 fJf MONOLITHIC 1OO/S1O.0O

.1 iA CERAMIC DISC 100/S6.50

.1 iA MONOLITHIC 100/S12.50



PS-IBM $99.95

■ FOR IBM PC -XT COMPATIBLE

■ 135 WATTS
. .5V@>15A, ?12V@4.2A PS IBM

-5V<tf.5A.-12V@J.5A

? ONE YEAR WARRANT*

PS-IBM- 150 $129.95

? FOR IBM PC XT COMPATIBLE
- 150 WATTS

? -12VP5.2A, >5V^ 16A
-12V <? .5 A. -5V @ .5 A

? ONE YEAR WAHHANTY ps_1



. 1 30 WATTS

? SWITCH ON REAR

■ FOR USE IN OTHER IBM

TYPE MACHINES
- SQDAYWARRANTY



- USE TO POWER APPLE TYPE

SYSTEMS
* +5V @ 4A. -12V @ 2.5 A

-5V (tf ,5 A. -12V @ .5 A
■ APPLE POWER CONNECTOR



PS-SPL20D



> *5V @ 25A? t12V @ 3,5A
-5V<B1A f -12V<E& IA

. ULAPPROVED

> ALUMINUM ENCLOSURE



BOOKSby STEVE CIARCIA

EIUJ-D YOUR OWN

, ZfiO COMPUTER S

I CIRCUIT CELLAR VOL 1 S H

CIRCUIT CELLAR VOL 2 ■ S 1

CIRCUIT CELLAR VOL 3 V

CIRCUIT CELLAR VOL A S'

, CIRCUIT CELLAR VOL 5 S'




MICROCOMPUTER

HARDWARE HANDBOOK

FROM ELCOMP $14.95

OVER 800 PAGES OF DATA SHEETS
ON THE MOST COMMONLY USED
ICs. INCLUDES TTL CMOS. 74LS00.
MEMORY. CPUs, MMJ SUPPORT.
. AND MUCH MORE!



o
o
Fj

UJ



<



106



DIMENSIONS



DISTRIBUTION
STRIPIS)



SS BREADBOARDS




LITHIUM BATTERY

AS USE D IN CLO CK CI RC U ITS



3 VOLT BATTEHY
i BATTERY HOLDER



NEW EDITION!

19BG
IC MASTER

THE INDUSTRY STANDARD

$129.95



VISIT OUR RETAIL STORE LOCATED AT 1256 SOUTH BASCOM AVENUE IN SAN JOSE



JDR Microdevices

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800-538-5000 ? 800-662-6279 (CA) ? (408) 995-5430

FAX (408) 275-8415 ? Telex 171-110



HOURS: M-W-F, 9-5 TU-TH, 9-9 SAT, 10-:

PLEASE USE YOUR CUSTOMER NUMBER WHEN ORDEPINi

TERMS: Minimum order S10.OO. For shipping and handling Include $250 for UP
Ground am) S3 50 lor UPS All. Orders o*er 1 |h. and lorMgn owers may requir
additions! dipping charges - please contact our him department for the amount CI
residenls must include applicable sales lai. All merchandise It warranted lor 90 day
unless otherwise slated. Prices are subject to change without notice. We are nr
responsible lor typographical errors We reserve the noht to tlmll quantllles and I
substitute manulacturer. All merchandise subject to prior sole.



S) COPYRIGHT 1986 JDR MICRODEVICES



CIRCLE 256 ON FREE INFORMATION CARD



PARTIAL LISTING ONLY — CALL FOR A FREE CATALOG



yaJtata

120 GPS DOT MATRIX PRINTER



DISK DRIVES

FOR APPLE COMPUTERS



flP-150
$90.95



' W HT. DIRECT DRIVE

? 1QQ% APPLE COMPATIBLE

I SIX MONTH WARRANTY



BAL-500
$129.95



fflrj



. TEAC MECHANISM DIRECT DRIVE
■ 100% APPLE COMPATIBLE
I FULL ONE YEAH WARRANTY



AP-135
$129.95



r FULL HT SHUGART MECHANISM
i DIRECT REPLACEMENT FOR APPLE

DISK II
?r SIX MONTH WARRANTY



DOUBLE

siotm
MAC535
$249.95 iz



- 3 5 ADDON DISK DRIVE

? 100-i MACINTOSH COMPATABLE

- DOUBLE SIOEO BOOK BYTE STORAGE
. HIGH RELIABILITY DRIVE

HAS AUTO EJECT MECHANISM

? FULL ONE YEAR WARRANTY



AD-3C
$139.95



^-'TI



* 100% APPLE lie COMPATIBLE.
READY TO PLUG IN. W SHIELDED
CABLE & MOLDED 19 PIN
CONNECTOR

- !: A ST RELIABLE SLIMLINE DIRECT
DRIVE

? SIX MONTH WARRANTY

DISK DRIVE ACCESSORIES

F D D CONTR O LLE R C AHO S49.95

Hi: ADAPTOR CABLE $19.95

ADAPTS STANDARD APPLE DRIVES

FOR USE WITH APPLE He



KB- 1000



CASE WITH KEYBOARD
FOR APPLE TYPE MOTHERBOARD

. USER DEFINED FUNCTION KEYS
. NUMERIIC KEYPAD WITH

CURSOR CONTROL
■ CAPS LOCK ? AUTO-REPEAT



KEVBOARD-AP $49.95

. REPLACEMENT FOR APPLE II

KEYBOARD
. CAPS LOCK KEY. AUTO BE PEAT
. ONE KEY ENTHY OF BASIC

OH CP'M COMMANDS



EXTENDER CARDS

IBM-PC $45.00

IBM-AT $68.00

APPLE II $45.00

APPLE lie $45.00

MULTIBUS $86.00.



APPLE COMPATIBLE
INTERFACE CARDS

EPROM PROGRAMMER $59.95



MODEL
RP525



-■_,_ -V-i. ....



. DUPLICATE OR BURN ANY
STANDARD 27kx SERIES EPROM

■ EASY TO USE MENU-DRIVEN
SOFTWARE IS INCLUDED

■ MENU SELECTION FOR 2716.
Z73Z. 2732 A, 2764 AND 271 26

■ HIGH SPEEDWRITE ALGORITHM

■ LED INDICATORS FOR ACTIVITY
. NO EXTERNAL POWER SUPPLY

NEEDED
> ONE YEAR WARRANTY



M 3-WAY SWITCH BOXES

SERIAL OR PARALLEL

CONNECTS 3 PRINTERS TO ONE

COMPUTER OR VICE VERSA

ALL LINES SWITCHES

HIGH QUALITY ROTARY SWITCH MOUNTED

ON PCB

GOLD CONTACTS

STURDY METAL ENCLOSURE



SWITCH-3F CENTRONICS PARALLEL $99,95
SWITCH 3S RS232 serial $99.95



IGKHrMGaRD



$39.95



■ FULL TWO YEAR WARRANTY
. EXPAND YOUR 48K APPLE TO

G4K
? USE IN PLACE OF APPLE

LANGUAGE CARD

I UK PC MM W/IMTMICTIOMS 59.35



IC TEST CARD



$99.95



? QUICKLY TESTS MANY COMMON

IC*
- DISPLAYS PASS OR FAIL

■ ONE VEAR WARRANTY

■ TESTS- 4000 SERIES CMOS.
74 HC SERIES CMOS,
7400 h 74LS, 74U74H&74S



1 300B MODEM $49.95

FOR APPLE OR IBM

INCLUDES ASCII PRO-EZ SOFTWARE



. FCC APPROVED

■ BELL SYSTEMS 103 COMPATIBLE
. INCLUDES AC ADAPTOR

■ AUTO DIAL

■ DIRECT CONNECT

I CABLE FOR APPLE lie $14.95 ,



[JOYSTICK CR-4Q1 $7.95

FDR ATARI 400, ?00, 260O,
VIC 20 64 AND APPLE II*



DISKFILE

HOLDS 70 S'i" DISKETTES



' DISKFILE holds 40 $9?* ,



POWER STRIP

yl/.aw



i UL APPROVED
. ISA CIRCUIT
B BEAKER



m. PRINTER BUFFERS

FREES COMPUTER FOR OTHER TASKS
WHILE PRINTING LONG DOCUMENTS
STAND ALONE DESIGN; WORKS WITH ANY
COMPUTER OH PRINTER
ALL MODELS FEATURE PRINT PAUSE
MEMORY CHECK. GRAPHICS CAPABILITY

SP120P PARALLEL SI 39.95

64K UPGRADABLE TO Z5GK

LED INDICATOR SHOWS VOLUME OF DATA

IN BUFFER

SP120S HS232 SERIAL $159.95

64K UPGRADABLE TO 2SGK

6 SELECTBALE BAUD RATES. FROM

S00B-T3.20OB

SP110P PARALLEL $249.95

i 64K UPGRADABLE TO 51 2K

? SPOOLS OUTPUT OF UP TO 3 COMPUTERS

* LED BARGRAPH DISPLAYS AMOUNT OF
OATA IN BUFFER

. RESET FUNCTION CLEARS

DATA IN BUFFER
■ REPEAT FUNCTION CAN

PRODUCE MULTIPLE

COPJES OF A DOCUMENT



l/t



NASHUA DISKETTES DEALS

5'/4" SOFT SECTOR
DS/DD WITH HUB RINGS

$990 69Cea 59Cea

B0XGF1O BULK QTT 50 BULK OH 250

NASHUA DISKETTES WERE JUDGED

TO HAVE THE HIGHEST POLISH

AND RECORDED AMPLITUDE OF ANY

DISKETTES TESTED ACCORDING TO

COMPARING FLOPPY DISKS". BYTE 9/84





DISKETTES






NASHUA 5V4"




N M02D
N-MD2F
NM02H


DS>DD SOFT
DS'QUAD SOFT
DS.'IID FOR AT

NASHUA 8"


$3.30
334.35
349.95


N-FD1
| N-FD2C


SS. DDSOFT
DS/OD SOFT

NASHUA 3.5"


$27.35
$34.95


N3.5S5


3 5'SS/DDFOH MAC

VERBATIM 51/4"


532.35


V-MDIO

V-MD2D

I V-MD110D


SS DD SOFT

DS/DD SOFT

SS/DD 10 SECTOR HARD


323.95
$23.95
$23.3Sj



MODEL

SP-1200



$169.95



- EPSON' IBM COMPATIBLE

1 SWIRE PRINTHEAD

1 120CPS-BIDIRECTIONAL. 80 COL

■ FRICTION AND TRACTOR FEED
I PROPORTIONAL SPACING

■ CENTRONICS PARALLEL INTERFACE

■ 8 CHARACTER SETS AND GRAPHICS

6 TOO T IBM PRIN TER CABLE $9.95

i REPLACEMENT RIBBON CARTRIDGE SI 1.95 j

5VV FLOPPY DISK DRIVES

TEAC FD-55B '.■',■ HT DS/DD (FDR IBM | S 1 09-95 I

TEAC FO-55F M HT DS/QUAD (FOR BMI S103.95 I
TEAC FD-55GFV <A HTDS.'HD IFOR IBM ATI $154.35 I

TANDON TM1Q0-2 DS DO FOR BM $99.95

TAND0NTM50 2 Vi HT DS/OO (FOfi (BMI $89.95

MPI-BS2 OS DDiFOfliBM/ $89.95

| OUMEOT-142 !4 HT DS/DD IFOR IBM] $79.95 |

8" FLOPPY DISK DRIVES



FO 100-S SS/OD (SVSOl EQUW
FD ZOO-B OS/DD ISA/851 ft EQUIV1



si 19.00
J159.00



DISK DRIVE ACCESSORIES

TEAC SPECIFIC ATI ON MANUAL 3500

TEAC MAINTENANCE MANUAL 9-25.0O |

Vi HT MOUNTING HARDWARE 12.95

MOUNTING RAILS FOR IBM AT *4.9S

"Y" POWER CABLE FOR S*V FDD. S2.95

5WFDD POWER CONNECTORS ?1.19



"^ mm.



* & * ?



TEAC FD-55



TANDON TM 100-2



DISK ORIVE ENCLOSURES

C*B-?PPLE $24.95

APPLE TYPE CABINET IN/OUT POWER SUPPLY

CIB-1FHS S6G.B5

FULL HT fiy. ,J BEIGE CABINET W/ POWER SUPPLY

CM-2IH $48.35

DUAL SUMUNE Bt" CABINET W/ POWER SUPPLY

CU-2IVI vertical S209B5

DUAL SUMUNE B" CABINET W POWER SUPPLY

CIB-2FHI hohizintal ?219.95

DUAL FULL HT 6" CABINET w.' POWER SUPPLY



^L



TEST EQUIPMENT FROM JDR INSTRUMENTS
DIGITAL MULTIMETER PEN DPM-1000



$54.95



AUTO RANGING, POLARITY AND DECIMAL!

■ LARGE 3.5 DIGIT
DISPLAY

. DATA HOLD SWITCH
FREEZES READING

? FAST. AUDIBLE CON.
TINUITYTEST

. LOW BATTERY
INDICATOR

- OVERLOAD PROTEC-
TION

20MHZ DUAL TRACE OSCILLOSCOPE MODEL 2000
35MHZ DUAL TRACE OSCILLOSCOPE MODEL 3500



$389.00
$549.00



FOR MORE INFORMATION ON THE OSCILLOSCOPES. SEE OUR FULL PAGE AD ON PAGE 13.



CALL FOR VOLUME QUOTES



?COPYRIGHT 1986 JDR MICROOEVICES



CIRCLE 257 ON FREE INFORMATION CARD



108



BUILD A COMPLETE XT SYSTEM— $698



XT COMPATIBLE
MOTHERBOARD

$159.95

? 4.77 MHz BOSS CPU, OPTIONAL

SO 37 CQ-PROCESSQfl
' 8 EXPANSION SLOTS

- OK RAM INSTALLED, EXPANDABLE
TO G40K ONBOARD MEMORY

- ALLICsSOCKETEDMIGHEST
QUALITY PC BOARD

? ACCEPTS 2764 OR 27128 ROMS

[PRO-BIOS $29.95




20 Mb HARD DISK SYSTEM



INCLUDES HALF LENGTH HD
CONTROLLER. CABLES, MOUNT-
ING HARDWARE AND INSTRUC-
TIONS ALL DRIVES ARE PRE-
TESTED AND COME WITH A ONE
. YEAR WARRANTY.



SEAGATE ST-225
$489.00



IBM COMPATIBLE IHTERFACE CARDS

ALL WITH A ONE YEAR WARRANTY

MULTI I/O FLOPPY CARD $129.95

PERFECT FOR THE&tOK MOTHERBOARD

? J DRIVE FLOPPY DISK CONTROLLER

? 1 RS232 SERIAL PORT; OPTIONAL 2nd
SERIAL PORT

> PARALLEL PRINTER PORT

■ GAME PORT
. CLOCK CALENDAR

■ SOFTWARE: CLOCK UTILITIES.
RAMDISK. SPOOLER




MULTIFUNCTION GARD



ALL THE FEA TURES OF AST'S 6 PACK PLUS AT HALF THE PRICE
? CLOCK CALENDAR



$119.95



xzwrsti



■DVie




m-tt



? 384 K RAM

? SERIAL PORT

' PAHALLEL PORT

' GAME PORT

■ SOFTWARE INCLUDED
PRINTER CABLE
G4K JMM UPGRADE



COLOR GRAPHICS ADAPTOR



S3 55
9IS8.91



§99.95



FULLY COMPATIBLE WITH IBM COLOR CARD

- 4 VIDEO INTERFACES: HOB.
COMPOSITE COLOR, HI-RES
COMPOSITE MONOCHROME,
CONNECTOR FOR RF MODULATOR
■ COLOR GRAPHICS MODE: 320 x 200
? MONO GRAPHICS MODE: 640 x 200
. LIGHT PEN INTERFACE




MONOCHROME GRAPHICS GARD



$119.95



FULL Y COMPA TIBLE W/IBM MONOCHROME ADAPTOR S HERCULES GRAPHICS

■ LOTUS COMPATIBLE
? TEXT MODE: BO * 25
. GRAPHICS MODE: 720 x 31S

■ PARALLEL PRINTER INTERFACE
- OPTIONAL SERIAL PORT S19.95




MONOCHROME ADAPTOR



$49.95



ANOTHER FANTASTIC VALUE FROM JDRi
* fcBIVI COMPATIBLE TTL OUTPUT - 730 X 350 PIXEL DIPLAY

PLEASE NOTE: THIS CARDWJLL NOT RUN LOTUS GRAPHICS AND DOES NOT INCLU DE A
PARALLEL PORT



FLOPPY DISK DRIVE ADAPTOR



$49.95




- INTERFACES UPTO FOUR STANDARD
FDD* TO IBM PC OR COMPATIBLES

* INCLUDES CABLE FOR TWO
INTERNAL DRIVES

. STANDARD DB37 FOR EXTERNAL
DRIVES

* RUNS OUAD DENSITY DRIVES
WHEN USED WITH JFORMAT



EASYDATA 1200 BAUD MODEM FOR IBM

INCLUDES PC TALK III COMMUNICATIONS SOFTWARE




■HAYES COMPATIBLE
- AUTO DIAL'AUTO ANSWER
■AUTO HE-DIAL ON BUSY
. INCLUDES SERIAL PORT!
■ ONE YEAR WARRANTY

$169.95



#JDR Microdevices



i



CRT MONITORS FOR ALL APP LICATIONS

I





1



TAXAN

RGB VISION III

MODEL 415

j MAOE DV TAKflN FOR ACORN
■ 640 ? 2G3 PIXEL RESOLUTION
16 CCLOR5
18 Mm HANDWIDTH
12" BLACK MATRIX
IHM AND LOTUS COMPATIBLE



SAKATA

COMPOSITE COLOR

MODEL SC-10Q

FOP ;;.-,- 1 u FOft APPiE
13** COMPOSITE VIDEO
RESOLUTION :■:■;■;:■ n ? mow
INTERNAL AUDIO AMPLIFIER .
ONE YEAR WARRANTY



GABLE FOR IBM



CENTER SYSTEMS

MONOCHROME

MODEL Ki.M-1211

■ IBM COMPATIBLE TTL INPUT

■ M" NOP! GLARE 5CRE?n|

■ P33 GREEN PHOSPHOR
VI!". HIGH RESOLUTION

25 ■.""- I--" NDIlWDI ii
>1CD LINES ICENTERi



SI 5.95



$289.95 $169.95 $99.95



BUILD YOUR OWN
XT COMPATIBLE SYSTEM!

XT MOTHERBOARD $159.95

PRO-BIOS $29.95

64K RAM $8.91

130 WATT POWER SUPPLY $09.95
FLIP-TOP CASE $49.95

DKM-2000 KEYBOARD $79.95
V2 HEIGHT QUME DRIVE $79.95
FLOPPY DISK CONTROLLER $49.95
MONOCHROME ADAPTOR $49.95
MONOCHROME MONITOR $99.95

TOTAL: $697.51



IBM STYLE
COMPUTER CASE

AN ATTRACTIVE STEEL CASE

WITH A HINGED LID FITS THE

POPULAR PC/XT COMPATIBLE

MOTHERBOARDS

. SWITCH CUT-OUT ON SIDE FOR PC/XT
STYLE POWER SUPPLY

■ CUT-OUT FOR 3 EXPANSION SLOTS

■ ALL HARDWARE INCLUDED



MONITOR STAND



T9LTSAIUO SWIVELS

ONLY $12.95

IBM PRINTER CABLE



■ DB25 TO
CENTRONICS ftn nc

■ SHIELDED CABLE OS. SO




$49.95



IBM COMPATIBLE KEYBOARDS
DKM-2000 $79.95 IBM-5151 $99.95






"5150" STYLE KEYBOARD

FULLY IBM COMPATIBLE

LED STATUS INDICATORS FOR CAPS &

NUMBER LOCK

S3 KEY SAME LAYOUT AS

IBM PC/XT KEYBOARD



n " " u,.Li.m::iu U



POWER SUPPLY



21 J~>



4.



NOW ONLY $89.95

FOR IBM PC-XT COMPATIBLE
13S WATTS

-5V @ 15A, t12V @ 4.2A
-BV @ -5A, -1ZV @ .SA

150 WATT MODEL $99.95



?$M-y-m^



■ REPLACEMENT FOR KEVTRONICS
KB-51S1~

■ SEPARATE CURSOR t, NUMERIC
KEYPAD

■ CAPS LOCK & NUMRER LOCK
INDICATORS

? IMPROVED KEYBOARD LAYOUT



DISK DRIVES

TANDON TM50-2

$89.95

* Vi HT DS DD

* IBM COMPATIBLE

* EXTREMELY QUIET!

TUG FD-55B DS/DD $109.95

TEaC F0-55F DS/QUAD $109.95

TEACF0-55B OS/HO $154.95

QUMEOT-142 DS/DD $79.95

MOUNTING HARDWARE $2.95

IT/MILS $4.95 .



1224 South Bascom Avenue, San Jose. CA 95128
800-538-5000 ? 800-662-6279 (GA) ? (408) 995-5430 * FAX (408) 275-8415 ? TeteK 171-110



?COPYRIGHT 19S6 JDP, MICRODEVICES

CIRCLE 258 ON FREE INFORMATION CARD



TENMA*



THE NAME YOU CAN
TRUST IN ELECTRONIC
TEST EQUIPMENT




WSBSt 35MHz Dual Trace
Oscilloscope

■ Two high quality 10:1 probes included

■ For additional specifications see MCM
Catalog #1 1
#72-330

$569°o J






TEMur 20MHz Dual Trace
Oscilloscope

■ Two high quality 10:1 probes included

■ For additional specifications see MCM
Catalog #11
#72-320



$3899?




TEMHWr

0-1 8V 3A
Power Supply

■ Regulated outputs — constant voli
current, both are continuously uaria
connected in series or parallel for more voltage
or current output ■ Reverse polarity and overload
protected ■ Isolated output .

#72-330 Available Mid May! <

$99 5 ° m

TEMHdt* Combination Function
Generator and Frequency Counter

■ 6 digit display ■ Output range: 2Hz-2MHz: seven
ranges ■ Counter range: ,1Hz-10MHz?5-15V TTL
and CMOS output ■Waveforms: sine, triangle,
square, pulse, and ramp.

#72-380




IfcMUt* Bench Top DMM

■ 314 digit ? Eight function DCV, ACV. DC A (up to
20A), ACA (up to 20A), Resistance (up to
20Mohm), Audible continuity test, diode test,
capacitance test (up to 20/jF)
Available Mid May! ,^h^m

1



#72-410



$149?o



$219?o




TEMMr Rotary
Dial DMM

■3V4 digit LCD display ■Rotary dial for
rapid selection of functions and ranges
■ 20 amp AC-DC current ■ .lohm
resolution ■Carrying case included
#72-075 $44.80 (ea.)



$4195



(2-up)



1



uMlffO
MMfUttfTI




TENMAlT-

Digital
LCR Meter



■ Measures inductance, capacitance and
resistance ■ L = VH-200H,

C = 1pF-200/jF, R = .010hm-20Mohm

■ Carrying case included.
#72-370



TEMVtar Frequency Counter



■ ii digit LED display ■ Measurement range
1Hz-120MHz?High input sensitivity of
20mV RMS j. _-_.-* — -

$189 95 1



■m




$149?5



1



Terms:



MCM ELECTRONICS

BSB E. Congress Park Dr.
Centerville. Ohio il5<35S"4n7S
(51 3] .434-0031

SOURCE NO. RE-20



? $10 minimum order 11 00 charge (or orders
under S 10,

? $20 mmi-mum Charge card order
■ Orders shipped UPS COD,

? Most orders, shipped wilhin 24 tours.

? Sales oHicb open fl. 30 am to 7:00 pm Saturdays
10:00 am to 3 pm EST.

? For prepaid orders add $2 75 for shipping and
handling.

? Should shipping antf hand hng charges e*ce*d
$2.?5 r the balance due will be seni C D



[Be Sure To Call
For Your FREE
Catalog!
Over 6,000 Items!

We also have ... a full line of test equip-
ment, computer accessories, telephone
accessories, speakers, television parts,
flybacks, yokes, switches, fuses, lamps,
capacitors, resistors, cartridges, styli,
wire, CATV equipment, the largest selec-
tion of original Japanese semiconduc-
tors in the country and more.



CALL TOLL FREE 1-800-543-4330

In Ohio 1-800-726-4315 ? In Alaska and Hawaii 1-800-858-1849



>

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CO
CO



CIRCLE 87 ON FREE INFORMATION CARD



109



\N hat's New at

AMERICAN DESIGN COMPONENTS?



"The Source" of the
electro-mechanical components
for the hobbyist.



We warehouse 60, 000
items at American
Design Components — ex-
pensive, often hard-to-find
components for sale at a
fraction of their original
cost!

You'll find every part you
need — either brand new,
or removed from equipment
{RFE) in excellent condition.
But quantities are limited.
Order from this ad, or visit
our retail showroom and find
exactly what you need from
the thousands of items on
display.

OpenMon. - Sat., 9-5



THERE'S NO RISK.

With our full 90-day warranty,
any purchase can be returned for
any reason for full credit or refund-



19" COLOR



X-Y
DISPLAY




Originally W^,W designed

for use in Atari J^^ coin-operated

games. Contains 3-gun color tube, focus
and brightness controls. Requires external
X-Y inputs, 250-O-24V transformer for
power. May be used for oscilloscopes, re-
programmed f or game use, or modified with
the use of external vertical and horizontal
oscillators to a raster scan display or TV
monitor for computer use. {IBM compat-
ible^ Transformer supplied.

Item # 5449 $ 9 9 -00 New



ADAM COMPUTER KIT'
(Less printer & w/o cabinet)




■I , IU WP



Build it yourself from subassemblies. Mo
wiring necessary ljust plugs together).
Hook-up diagram included. Includes: Key-
board, 2 cassette digital data drives. 2
game controllers, power supply, all mem-
ory boards, and one cassette. Is capable of
running CP/M. has built-in word processor.

Item C7410 $99.00 Icomptetet



COLECO VISION KIT
(Assemble yourself, diagram incl.l




DISK DRIVES



V, HT

96TPI

DS/Quad

Tandon #TM55-4

Item #1901 $79.50 ea

or2lor$150.Q0




FUU.HT

96TPI

DS/Quad

Tendon 0TM1O1-4

Item #1901 $99.00 ea



MP1 525 (IBM? Compatible)

5% " FULL HEIGHT
DISK DRIVE




Double sidedVdouble density, full
height drive. 48 T.P.I., 80 tracks.
Item #7928 $79.95 New
2 for $150.00



ADAM CASSETTES

I Assorted)




Buck Rogers, BASIC -
plus others!

Can be easily erased.

Item #7786 — Bakers Dozen

13 for $19.95 New



75-KEY MECHANICAL
KEYBOARD - For Adam




For computer upgrade , . .
21 user-defined keys, SPST me-
chanical switches, 21 -pin ribbon
cable connection. General instruc-
lions for replacement of membrane
keyboards incl. Update computers
such asthB Timex Sinclair Z81 /1 000
Dim,: 13?"Wx IW'HiS'D.
Item #7429 $5.95 New



ADAM PRINTER
POWER SUPPLY

I Lin oar)




DC Output: -5V (JD 200 ma.

+ BV @ 3 amps

+ 12V @ 2.9 amps

+ 1 BV [inductive) @ 1 amp

Input: 115W60HZ.

Chassis Dim: 11 "W x 4"H x 8'D

Item #6642 $14.95 New



COMPUTER

TAPE DRIVE (For Adam)




Serial formal. Search 80IPS -
Read Write 20IPS. 1 2V motor, 5V
logic, 8 & 9 pin connector cables.
Originally designed for the Adam.
Dim: 5"W x 3W "H x 4" deep
Item #8841 $9.95 New



ADAM

REPLACEMENT

KEYBOARD

I ASCII 75-Key)




21 user-defined keys. 7-pin con-
nection, ASCII 8-bit serial output.
Originally designed for the Adam.
Dim.: 15-Wx 2K"H x6'/i- D
ltem#6643 $19.95 New



SWITCHING
POWER SUPPLY




115 a 230V, 47-440 Hz.

Input; 9O-135VH80-270V

Output: 5VDC @ 5-5A
+ 12VDC @>.4A
-12VDC @> -3A

Perforated metal case enclosure.

Dim.: 9(4"Lx3?"Wx2"H.

Mfr — General Instrument

Item #7983 $14.95 Now



12" COMPOSITE
VIDEO MONITOR




Green phosphor; 40/80 column,
1000-line resolution. IBMHz
bandwidth. Compatible with ISM,
Apple, Commodore, and more. In-
eludes external transformer for
operation on 1 1 o VAC & video
cable. Mfr - Elston Elec. #DM30
Item #6602 $29.95 New



Rechargeable NICAD

BATTERY

BACKUPS

12V @ 450 ma

Contains 1 AA cells. Recharge
rate: 45 ma. 16-18 hours. Case
with tab output connections.
Dim.: 2V?"H x 1 14 "W x 2 , Vi."L
Mfr - GE 123233 or equrv.

Item #5443 S $5.95 RFE

13.2V

@ 1.65 AH

Contains 1 1 C cells.
For model boats, toys, etc,
Mfr - GE #41B035BB00101
Item #5444 $15.95 New




ADC KITS

ROBOTICS KIT {Springs, Belts
Pulleys 6 Gears) Consists of:
9 Timing Belts (7. 5" to 13" I; 2

Round Salts II 2" to 1 5 "); 1 5
Nylon & Plastic Spur Si Drive Gears:
22 Torsion Springs; 6 Compression
Pulleys; 1 9 Tension Springs

ltem#5306 $14.95 New
TOY MOTOR KIT
For Robotics -

Consists of: 1 8 asst. toy motors
from 1.5V to 12VDC.

Item#7229 $9.95wew
SWITCH KIT
35 Ass't. Switches
Consisting of 35 assorted: Dip,
Toggle, Slide, and Sensitive Minia-
ture and Standard Size Switches

Item #5307 $9.95 New



PUMPS- COMPRESSORS- BLOWERS- MOTORS -POTENTIOMETERS- COUNTERS
TIMERS-RELAYS-VOLTAGE REGULATORS -POWER SUPPLIES



Item
No.



Many?




115 CFM MUFFIN FAN




115 VAC/60Hz., 21W., 28A.,
3100 RPM: 5-blade model, alu-
minum housing. Can be mounted
for blowing or exhaust.
Dim.: 4 1 Vift"sq. x 1 W "deep.
Item #5345 $7.95 RFE



30 CFM
MINI FAN



12VDC




Low noise level. Can be mounted
for cooling or exhaust. 1 2VDC.
Dim,: 3%" sq. x 1 14" deep
Mfr - Papst #8312
Item* 70 17 $12.95 New



REPLACEMENT BOARDS FOR ADAM
(For Parts Only!




^^ of the 'ADAM'

Logic board for the Adam com.
puter. Includes the following
components: 3 ea. 4164-4s,
74LS1 57. 74LS541 . LS273N;
2 ea. LM339s. plus micro-
processors with ROMs.
Mfr — Coleco
Item #7231 $9.95 RFE



GAME BOARD
Contains over ISO components!
8ea. 4116s, Z80A; 14 ea.
74LSs: 3 connectors, capacitors,
diodes, etc.

Dim.:9V,"Lx 10"Wx 1"H
Item #7679 $6.95



AMERICAN DESIGN COMPONENTS, 62 JOSEPH STREET, MOONACHIE, N.J. 07074
YES! Please send me the following items: □ My check or money order is enclosed.

□ Charge my credit card.



Description



Price



Complete unit, without housing. Can be
easily mounted on any base. Contains:
game board, 2 controllers, power supply.
TV game switch & connecting coaxial cable.

Item #7411 $19.95



Total

Shipping & handling, we ship UPS unless

otherwise specified. Add $3 plus 10% total.

anodian: S3 plus P.O. cost. Charge only.

Sales Tax IN. J. residents only,

please add 6% of totalf

OHDER TOTAL



□ Visa

Card No,



n Master Card □ Amex



MINIMUM

ORDER

$15.

RE- 5 6



Exp, Date


Signature








Telephone ■ Area Code


Number






Mame


Address


City


State




Zip





Ait inquiries and free catalog requests Celt 201-939-2770.



For all pttfne orders, call TOLL-FREE 800-524-0809. In New Jersey, 201-939-2710,



110



Radio /hack Part/ Place

SUILDER'S STORE! OVER 1000 COMPONENTS IN <




Plug-In PC Boards

(2) ^_ —



(3)



Socket < 4 t
For Boards ^^^p^^^^p



(1) Board With RS-232 Ports. Accepts two
RS-232 connectors. Predrilted DIP pattern.

45/16 x 5s/,s". #276-187 3.99

90° RS-232 Connector. #276-1521 3.29

(2) Multipurpose Two-Bus Board. Predrilted
DIP pattern. 41/2 XT #276-152 2.99



Three-Bus Version of Fig. 2. #276-154 . 2.99

(3) Jumbo Two-Bus Board. Accepts op to 24

16-pin DIPs. 4 1 / 2 x99/i 6 " #276-190 5.95

Jumbo IC/ Discrete Board. Accepts up to 40
Sixteen-pin DIP ICs. #276-191 5.95

(4) 44-Position Socket. #276-1551 2.99



Battery
Guidebook

NEW!
199

Helps You Select
The Right Battery



Learn haw batteries work, how to recharge and
test them, and how to choose the best values.
Includes complete technical data 011 all ENER-
CELL* balteries. 160 pages. #62-1396




Add Some Action with Our
Bargain-Priced DC Motors

SPECIAL IMJltOMSI-!



(5) (6) (7)

9 (5 n



Fig. DC Volts I Cat. No.


Only


5 1.5 to 4.5 273-225

6 1.5 to 3 273-226

7 3 to 4.5 273-228


993 Each
Pkg. 2/1.19
Pkg. 2/1 .29



Fine-Tune Your Circuits



(8) ' I (9) I?



(8) PC-Mount 15-Tum Pots. a/j-watl. Eacn 1.49



no) tr




Learn as You Build with Our
Project Books and Parts Kits



OKms


1000


10k


20k


Cat. No.


271-342


271-343


271-340


(9) PC Board Pots. Va-wa


tl Each S9e


Ohms


Cat. No.


Ohms


Cat. No.


SCO
1k
5k

10k


271-226
271-227
271-217
271-218


SOk
100k
1 meg


271-219
271-220
271-229


(10) Miniature PC Pols. '








1ti

10k


271-333
271-335


25k
iO0k


271-336
271-338





Timer IC Mini-Notebook. #276-5010 99

Timer Project Parts. #277-061 11.95

Op Amp Mini Notebook. #276-5011 1.49

Op Amp Project Parts. #277-062 11.95



Breadboard
Socket.
#276-174 . . 11.95




Values in sight and sound

(11) (12) __ (13)

^3n (= "



CMOS and TTL Digital ICs



ffcfi



Top Quality

With Pin-Out and Specs



Heavy-Duty
Automotive Relay



3=2



(14)



(11) Two -Tone Plezo Buzzer. Super-loud 100
dB sound level. 8-16, VDC. #273-070 8.95

(12) Piezo Buzzer. Steady or pulsed output. 90
dB level at 12 VDC, only 10 mA. #273-068, 6.95

(13) NEW! Super-Bright Fled LED. A break-
through! Typically 300 mcd at 20 mA, T-1 a lt size.
#276-066 995

(14) CQX21 Blinking LED. IC driver and red
LED in aT-1 3 /i housing. Great for electronic jew-
elry. #276-036 1.59



Description


i ype


Cat No.


Each


Quad 2-lnpul NOR Gate
Ouad 2-lnpul MA NO Gate
Dual Typs-D Flip Flop
Decade Counler/Divider
Inverting Hex Bulter
Ouad Bilateral Switch


4001

4011
4013
4017
4049
4066


276-240!
278-241 1
276-2413
276-2417
276-2449
276-2466


.99
.99
1.19
1.49
1.19
1.19




Descriplion


Type


Cat. No.


Each


Ouad 2-lnpul NAND Gale
Hex Inverter
Quad 2-lnput AND Gate
BCD to 7-SeQment Driver
Divide by 2/5 BCD Counler


7400
7404
7408
7447
7490


276 1801
276-1802
276-1822
276-1805
276-1608


.69

.99

1.29

1 69

1.19



Only

?|99 ?




S9



Here's the sale way to control high-power light-
ing, ham radio power supplies and other heavy-
current auto accessories. SPST contacts are
rated 30 amps at 12 VDC. 12 VDC coil With
mounting bracket. #275-225



Modem Testers for Your workbench




Digital Multitester With Autoranging. Just select the function and our
accurate Mieronta* DVM does the rest! Features easy-to-read LC dis-
play, fuse and overload protection. Measures AC and DC voltage, DC
current, resistance, and has a "diode-check" mode for semiconductor

junctions. With probes, spare fuse. #22-188 34.95

Sale! Digital Logic Probe Now S3 OH. The fast way to test TTL, LS and
CMOS circuits. LEDs and tone output indicate high, low or pulsed logic
States. Reg. $19.95. #22-302 Sale 16.95



Put These High-Tech ICs to work



Give Your
Computer a Voice



^^^W



New Touch-Tone
Decoder



mmtmm




SP0256-AL2 Speech Synthesis IC. This 28-pin MOS LSI device uses a
stored program to produce natural sounding speech. With circuit exam-
ples and detailed data. #276-1784 12.95

CTS256-AL2 Text-to-Speech IC. This 40-pin device translates ASCII
characters into control data for the synthesizer above. Makes it easy to
add voice to most computers and terminals. With data, #276-1786, 16.95
NEW! SSI 202 Touch-Tone Decoder IC. The "missing link" between the ■
phone line and a device you want to control remotely. 18-pin package
contains a complete DTMF receiver that detects either 12 or 16-digit
formats. With data and circuit examples. #276-1303 12.95



Over 1000 items fn stock: Binding posts. Books, Breadboards, Buzzers, Capacitors, Chokes, Clips,
Connectors, Fuses, Hardware, ICs, Jacks, Knobs, Lamps, Multitesters, PC Boards, Plugs, Recti-
fiers, Relays, Resistors, Switches, Tools, Transformers, Transistors, Wire, Zener Diodes, more!



Radio /hack

A DIVISION OF TANDY CORPORATION

Prices apply al oafticl paling Radio Shack stoies and deaiefs



>

-<

CD
07



111



CIRCLE 78 ON FREE INFORMATION CARD



THE MOST POPULAR PRODUCTS IN EUROPE & ASIA ARE COMING NOW! 50 HOT ITEMS
EOR YOUR SELECTION. SEND $1.00 FOR MARK V CATALOG. REFUND UPON ORDER



CORDLESS SOLDERING IRON
RECHARGEABLE ^ +**

No. 620



*



The most parted handy j lightweight soldering iron for Work-
shop, K-tamft, Hobby & Outdoor' work . . . r

Includes UL gppravaF charger Si denning sponge.

With liuiSd'ln solder point illumination.

Each set J22.BQ



TALKING CLOCK
/



100W DYNAMIC CLASS "A"
MAIN POWER AMPLIFIER

TA-1DO0A ^SC

* f

This powerful dynamic bias class "A* circuit mokes thl* unit

unique rn its tiass. Crystal clear 1QQVY R.MS. POWER Output

will satisfy inB rnose pieJty HI - Fl fans. This is a single channel

amplifier. LI you need a SlBtbd effect you can buy two lo make

a total of 20OW DYNAMIC POWERI

Over 300Q KITS ARE SOLO IN THE STATE!

A?. with t*Sted $51.95




2% DIGITAL MULTIMETER

Y AM ATO 4Q D 1 >H^w>^Vj^W-<

3 SPECIAL OFFER 1 i




The YAM ATO 4001 is B 3^ DIGIT COMPACT DIGITAL

MULTIMETER, it employs FE type LCD. with large figures. Its
ADVANTAGES: High accuracy in measuring. High impedance
assures min. measuring error, One rotary switch allows fast &
convenient operation. 26 measurement range enabia widnr
application. Over-input indication fi. low battery I if 6 appears on
display- LSI-circuit us? provides hlflh reliability and durability.
Measurement possible even under strong magnetic field.
Not a KlT r assembled with tested ?33.80

LCD THERMOMETER CLOCK

, NEW'



The heart o( this Preamplifier is TL-9S4 IC which contains 4
Bl-FIT operational amplifier and has very good transient
response and low distortion.

High precision NF-CR MM cartridge amplifier has a superior
distortion characteristic Ness than O.OOS^ft] and RIAA equaliza-
tion j0.2dB,. It reproduces ma-lodical sound.
It has 40 steps volume control, seperale high, middle and low
tone control,, tone compensation and tone defeat system,
it is compatible with any power amplifiers which are made by
our compeny such as TA-1Q00A, TA-477, TA-802.

S44.50





■SPECIALS-
KITS
OFFER!



Features:

0,34" DIGITAL thermometer wilh Hi Sl Low temperature alarm

function and 12 hours dock combination.

Measuring range: 0'F to 160"* For -ZO*CtO + 7D T C.

Resolution reading: ±KS*F.

Dimension: 3.2" X 0-86" X 2-08",

T-1 with In/Qut Door sensor . . , $20.00

T-2 with Fahrenheit/Celsius measuring . $18.00 NOT A KIT-



KIT ONLY $25.00

You can own a stereo TV from today! This simulator is a
special design of using the most advanceibla monoploised
L.S-l- If produced a superior analog sia-rao effect since the
LS.I. Is equalled 60 pes. ol LOW NOISE FET & TRANSISTOR.
The simulator can even help you lo promote your tetania ion
From a normal One to a special one with a Hi-Fi STEREO func
tian. Our simulator is also applicable to any other "mono
sources' in covering it to ANALOG STEREO. Undoubtedly, it is
the most advanced equipment for every family, while It
should contribute to your listening pleasure.
Ass. with tested S30.00



10W AC/DC
SHOULDER AMPLIFIER



Jfc



TA-Q&fl employs the mosi advanced LC, of TOSHIBA, es a
main device, ihe sound Is powerful, it can be supplied bv only
4 pieces of 'UM-1 ' 1,5V battery or AC to DC 6-3V adaptor, tt is
simple lo operate, just 'press-lo-lalfc', and with QN-OFF power
switch on the mike. Besides, while It Is well "packaged and
with fight weight, so it is convenient to bring along in both
indoor and outdoor activities. Please Read our catalog for
details.
Assembled with tested ,?..,,, S4S.00

"cOLOrT^

TY-23B




As a result Of the advanced technology, this unit can controf
various colorful light bulbs, the Visual effeel of whith is moil
suitable in places like party, dSsco, electronic game centre end
also m lightings for advertisement. Totaf output power is
3000 W i 1 000 W/C h. ) which means that it can control 30 pieces
of 100W or 600 pieces of SW color light which is enough lor
most usages.

Kh ? . S0S.00

Ass. with tested , 575.M

TA^2400A ELECTRONIC ECHO AND
REVERBERATION AMPLIFIER

< REM IX records you rself ! $



This unit combines the most advanced computer V.LS.l.

technique wilh high quality Japan Made campDnant. so it has

the foil owing FEATURES!

h cen generate various reflection and reverberation effect such

as that in valley and music hall. It has a 3 section effect control

which includes reverberation control, delay control and depth

control. Specie! effect can be made in your record tapes by

using this modal. A3I kinds ol infield sound effect can be

obtained by skilful use o( this control- It ties LED display to

show reflection and reverberation,

Ass. with tested 599.85

hUGiTouALrfT

MULTIPURPOSE PRE-AMPLIFIER




This specially designed pre- amplifier includes a professional
GRAPH EQUALIZER TONE contra] system and has e gain to
1 2d B , Frequency res ponsa extends from SHi to 20KHi, so even
In bad listening condition it can improve well. It can accept
input from variouoos magnetic cartridge, record deck and
tuner, its output can be connected to all kinds of power
amplifier! The following combinations are good examples.
Assembled with tested 190.00



Model \u. Df'::n;.iro-

TA -00 1 1 W Mini Amplif jar

TA-006 GW Mini Amplifier

TA-007 12W Stflrco Power Booster

TA-00B AC/DC SHOULDER AMPLI F IEH

TA-10 STEREO PHE-AMPLIFIER WITH MAGNETICMIC AMP

TA-50 A, B MULTI-PURPOSE MELODV GENERATOR

TA-120 PURS CLASS "A" MAIN POWER AMPLIFIER

TA-202 20W AC/DC STEREO AMPLIFIER

TA- 300 30W Multi-Purpoie Single Channel Amp.

TA-302 SOW Scerao Power Sooner

TA-323A High QuflNtv 30W+30W SlcrrO Amplifier

TA-322i GQW IC Stirto Pre-Amphfiar Si Power Amplifier

TA-400 J0W TRANSISTORIZED MONO- AMPLIFIER

TA-477 120W MOSFET POWER AMPLIFIER

TA-800 S0W4$OWOC LOW TIM PRE-AMPLIF|^R ft POWER AMP.

TA-SQ2 80W+eOW PURE DC STEREO POWER AMP. hWSPEAKERl

TA-S20A 60W+60WOCL DC PRE-MAIN & STEREO AMPLIF IER

TA-1000A I00W DYNAMIC CLASS "A" MAIN POWER AMP IMONQJ

TA-1500 100Wx2 NEW CLASS "A" DC STEREO PRE-MAIN AMP

TA-240QA ELECTRONIC ECHO AND REVERBERATION AMP

TA-2500 HIGH QUALITY MULTI-PURPOSE PRE-AMPCIFIER

TA-2200 DC FET SUPER CLASS "A" PRE -AMPLIFIER

TA-2800 NF-CR BI-FETPRE-AMP (WITH 3WAY TONE CONTROL)

TA-3000 STEREO StfvtULATOR

SM-43 3 1/3 MULTI-FUNCTIONAL LED D.P.M,

SM-4B 4 1/2 HJ-PRECISION D.P.M,

SM-100 150MC UNIVERSAL DIGITAL FREQUENCY COUNTER

TY-43 3 1/2 DIGITAL PANEL METER



Am



Ah
Kit



KityAfscmblad Unn Price

Kil $3.90

Kit S4.92

Kit $$.00

S4E.D0

Sfi.00

S 10.76

S25.00

S60.00

S1 1.07

S5O.00

S 60-00

*24,6Q

529,50

S13.S4

S61-2B

S55.SFJ

?39.95

$4300

$51 .95

$67.00

tg&jjs

SS*J30
338.00
S44.50
S30.00
S25.00
529,23
S35.00
S3S.D0
S43.00
$99.00
S2S.00



Model No.
TR-3S5 A. B
TR-503



TY-1A MM

TY-7

TY-11A

TV l^A.

TV- 13

TY-14

TY-ig

TY-20

TY-23B

TY-25
TY-35
TY^36
TY-33
TY-41 MKIII

TY-42

TY-45

TY^47

YAM ATO 4001

T1

T2

8604

SS02

NO. 620

NO. 38E

Ail'Atitml>l*<J



Deccnpilon

3-5A REGULATED DC POWER SUPPLY

0-l5Vr3A POWER SUPPLY WITH SHORT CIRCUIT BFiEAK

& OVERLOAD PROTECTOR

0-16V2A REGULATED DC POWER SUPPLY

BATTERY FLUOPESCENT LIGHT

ELECTRONIC TOUCH SWITCH

MULTI-FUNCTIONAL CONTROL H ELAY

DIGITAL CLOCK WITH TWO TIMER

COLOR LED VU METER

ELECTRONIC SHOCK

HIGH PRECISION SOUND CONTROL SWITCH

SUPER SENSITIVE COLOR POWER LEVEL INDICATOR

COLOR LIGHT CONTROLLER

SPEAKER PROTECTOR
FM WIRELESS MICROPHONE
AC/DC OUAHTZ DIGITAL CLOCK
SOUND OR TOUCH CONTROL SWITCH
INFRARED REMOTE CONTROL UNIT

BAR/DOT LEVEL METER
BAR/DQT AUDIO LEVEL DISPLAY
SUPERIOR ELECTRONIC ROULETTE
3W DIGITAL MULTIMETER

LCD THERMOMETER CLOCK W/lNrOUT DOOR SENSOR
LCD THERMOMETER CLOCK W/P7C" MEASURING
TALK ING CLOCK MYNAH
TALKING CLOCK COCKATOO
CORDLESS SOLDERING IRON RECHARGEABLE
TURBO SCREW DRIVER RECHARGEABLE
form. 1 1 is fully criwlsfd and t?tKi.



Kit/Atiembled



Kit

Kit

&SET

eSET

? SET

*>5ET

*>SET

#SET

&SET



Unit Price
S3 .90

Si 0.25

$69.50

S59.50

S3 .99

$5.50

$3 99

$13.36

SIT. 50

$3.00

$7.63

$19.50

S65.00

S75.00

S9 50

57,66

$16.92

$10.00

525.00

$30.00

$21.00

$34.35

S 16.92

S33-B0

$20.00

sie.oo

$25.00
$25.00
$22.80
$30.00



TERMS;

MlntrdET SIQ.0C
Charge card order: 520.00



All merchandises are subject to prior sals
Shipptr^g & Handling: Inside L A, 5% of total



NO C. 0. D. I Cashiers check, phone orders accept, order (Min 1 .50) . Outside L A. 1 094 of total



Calif. Res Md 6.5% Sales Tai.

Prices are subject to change without notice.



oroer [Min 2.50) . Outside U.5J*. 20% of total
order (Min 5.00).
Shipped by UPS



CIRCLE 259 ON FREE INFORMATION CARD



MARK V ELECTRONICS INC.
248 E. Main Street,
' "■ V1 Suite 100,

:-J I I Alh3mbra,CA91801

Information (818) 282-1130
mom - f hi io.oo to S:oo Orders (818)282-1196

SATURDAYS -9:O0 TO IS: 00 P.O.BOX 706S ALHAMBHA. CAB 1 802
TELEX 3716014 MAHK D



HOURS MOM- FBI 10.00 TO 5:00



W8B-KEYH1 -800-344-4539



COR



O ft A T I O N



AK, Puerto Rico - 21B-681-667*



T?l*? - S2B279H



TWX - 9103508SSIDIGI KFV CORP




NATIONAL SEMICONDUCTOR ? PANA5QN JA%_, -_-? , 1K ? , , - . . nD ? ? ? 1 rniia *c in 11 - 00 QfilQ ?°DES ? DIAMOND TOOL ■ UNGAR ? f
OK MACHINE -EWC, INC ? INTERSIL" AD f 3 256K Ud^,144 X 1) UHAM lbUNb SO./UH, 5da.9DjS ES ■ CW INDUSTRIES ? AMDEK ? G.E.
INS %$*$ r— v, ??.?



Factory Frrsts



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IT I 1 "L? '. "i T, ? \i..\..-



SERVICE CHARGES VOLUME DISCOUNT

* O.OQ i 9.S Add ?2.Qd J P.EB t 59 M MET

* 10.DDt2S.00 Addtg.75 * t00 .00-4249 99 UnlBY.

t 2S.00-i44.!f$ Add WW 4 2M.0Q MS9 M Let* 15%

t W.00 HMt . ,., AddlD.2b 4 W0.iM3.939 99 lns20-

?100OAUp Nu Charge 41000 & Up L*h 2B%



CIRCLE 82 ON FREE INFORMATION CARD



7400


Port No.


Price


Part No.
SN74B5N


Price


SN7400N


19


55


SN7402N


19


SN74B6N


35


SN7404M ....


.25


SN7489N. . . .


....1.95


SN7405N


3a


SN7490N


.... .38


SN7406N


29


SN7493N


35


SN7407NT.


29


SN74121N


29


SN7406N


25


SM74123M.. .,


.49


SN7410N.


19


ShT74125N


.45


SN7414N


45


5N74126N.....


49


SN7416M


35


SN74143NL . . . .


.... 3.95


SM7417N


35


SN74150N


129


SW420M ....


.19


5N741 S4N. - , .


1.25




, 19


SN74156N. . . .


. ... 159


SN7432M ....


29


5N741 73M ....


75


SN743BN. ....


29


SN74174N


59


SN7442N


...... .45


SM74175N


59


SN7445N. ....


?9


SN74176N


39










SN7447N


.79


SN74189N.. . .


.... 1 .95




.78


SN74193N


69










SN7473N


,35


SN74221N


39


SN7474N


.35


SN74273M . . .


.... 195


SN7475N


39


SN74365N


39


SN7476M


35


SN74367N


. 59



74LS00.


19


74LS165


79


74LS02.


.19


74L81 66.


,89


74LS04


.... 25


74LS1 73


.49


74LS05


.... 25


74LS1 74.


39


74L506


.99


74LS175


39


74LSD7.


.... ?9


74LS189.


395




.19
19






74LS10


74L5T93.


..... ?9


74LS14


.39




59


74LS27


25


74LS240.


39


74LS30.


19


74LS243.


69


74LS32


25


74LS244,


39


74LS42


..... as


74L5245.


..... .79


74LS47


.89


74LS259


1.19


74LS73,


35


74LS273.


.79


74LS74.


25


74LS279.


39


74LS75.


29


74LS322


2.95


74LS76


29


74LS365.


39


74LSB5


.49


74LS366


39


74LSB6.


25


74LS367


39


74LS90


39


74LS36a


39


74LS93


39


74LS373. ....


.79


74LS123.


49


74LS374


79


74L512S.


39


7JLS393.


.79


74LS138.


39


74LS5SO,


5.95


74LS139-


39


74LS624.


1.95


74LS1 54


.... 1.49


74LS629.


249


74LS1 57. ....


.35


74LSS40.


.99


74LSTSS.


35


74LS645.


.99


74LS1 53


.49


74LS670.


99


74LS164


49


74LS6B8.


1.95





74S/PROMS*




74S00


29


74S188*


1.75


74S04. .


35


74S189


.. 1.95










74S1 0. .


29


74S240


. . 1 .49


74S32. .


35


74S244.


. . 1.49


74S74. .


.49


74S253


... .79


74SB5. .


1.49


74S267". .......


..1.69


74SS6. .


35


74S28B'


., 1,69


74S124.


2.75


74S373


.. 1.59


74S174.


.79


74S374.


.. 1.69


745175.


79


7-1S472*


. . 3.49



74ALS



74ALSDO.


35


74ALS138... . -


... 39


74ALS02.


.... 35


74ALS174


.... 39


74ALS04


39


74ALS175....


.... 39


74ALS08.


.... 35


74ALS240


.... 1.79


74ALS10.


.... 35


74ALS244. ....


.... 1.79


74ALS27,


...39


74ALS245


... 2.49


74ALS30


.... 35


74ALS373


.... 1.95


74ALS32


.... 39


74ALS374


1.95


74ALS74. . ,


.... .55


74ALS573


.... 1.95



74F



74FOD


59


74F1 39


1 .29


74F04


35


74F1S7


129


74F08,


.59






74F1Q.


59


74F240.


2.49


74F32


?5


74F244


2.49


74F74


?9


74F253.


1.79


74F8S


39


74F373.


2.95






74F374 . . .











CD— ?


SfflOS




CQ4O01


19


CEM0S1


... 25


CD4011..


19


CO40S2


25


CO4013. .


35


CD4093


. ... 39


CCM016.


29


CD4094.


. . . 1.49


CD4017. .


.49


CD40103.


. . , 2.95


CD401&.


69


CD4S03


. ... .49


CD4G20. .


.59


CD451 0-


69


CD4024. .


.49


CD451 1


69


CD4027. .


39


CD4515,


. . . 139




39






CD4O40. .


65


CD4520


. ... .79


CD4049. .


29


CD4522


.79


CD4050. ,


29


CD4538


89


CD4051..


.65


CD4541


.... .89


CD4Q5Z .


65


CD4543


.... 99


CD4053. .


65


C04553


. . . 4.95


CD4059. .


3.49


CD4555


... .89


CD4060. .


B9


C04566.


. .. . 195


CD4066. .


29


CD45S3.


.... 1.19


CO40S9. .


25


CD45S4.


.... 59


CD4070. .


29


CD4585.


75


CD4071..


25


MC14411


... 9.95


CD4Q72 .


25


MC1449QP.


4.49


CD4076 .


39


MC14572.


. ... .89



PRICE BREAKTHROUGH!

CUSTOM COMMODORE CHIPS
for VIC-20, C-64 and C-128 Personal Computers



Prlcft Part No.



Prlca Part Mo.



?G510CPU 4*95- 9.95
■652STPI -?fc9S- 9.95
*Spec9. A*a Hack @ S1 -M ea.



■652GCIA *fc?5- 14.95
■6560 VIC-! JMf 14.95
■6567VIC-ll44*6 19.95



?6581SID ,9S#fr 19.95
BZS100PLA .:.-?- 19.9S
NOTE: JH2S10Q = U1 7 (CM)



."



,:W0*?"



MC68701 -Microcomputer with EPROM

Tne MC66701 13 ar> 8-blt single c*iip microcomputer unit (MPIJ)
which slgmNcantly enhances the capablFrtles of ;iie MC&BQO
lamJycrf parts. On-chip resources Inclijde 204S bytes of L^PfTOM,
1 28 bytes of R AM r Serial Communications Interface (SCI), paral-
lel L/O, ancf a thrae function Programmable Timer.

MC68701. $24.95



MICROPROCESSOR COMPONENTS



Ml C BO PH DC ES SDH CHIPS
Pert No. Price



D765AC

CDP1B02CE.


4.95
9.95


ISO. ISOft. Z&0H, SERIES

ZBO 1.75

Z80-CTC 1.79


zeo-DApn-. —

Z80-P10.


495
1.79


Z80A-CTG . . .

ZSOA-OAFiT. . . .
Z8OA-P10. ....
Z80A^S10/a . .
Z60B.

z30b<;tc

Z8OB-P10


1.89
525
. . . 1.95
.525
3.95
4 95


05 DO /6B 00 ,'680 DO SEH










6532

S551


6.49
6.95










6621


. . . 1.95



650C/&BQ0/68DDQ Ggnl.

Part Uo. Price



6840


. . . 675


6843


. . 19.95






6650.


. . . 1.95






66000LB


. . . 9.95






8000 SERIES


8031


. . . 695


80C31BH


. . 19.95


8035.


... 1.95


&073M


. . 29.9S


8080A.


. . . 3.95


BQ85A.


. . 275


8086-2


, . . 695


6087 (5WHZ)...


. 129.95


B087-2(aMHz).


. 139.95


6086


. . . 7.95






8155


. . . 2.75


8156


. . . 2.75


8202


. . . 9.95


8203


. 29.95


821 2.


- , 1,95


8224


. . . 225


8228.


. . . 3.49


6237-5


. . , 6.95



BDQQ SEFllFSCnni.
irt No. Price



3243


.. 249


B250A


. 695


8250B (For IBM) .


...5.95


8251 A


.. 225


B253-5


..225


8254


..995


8255A-5.


..2J25


8257-5.


. . 2.49


8259-5


. . 2.49


8272


..4.95


8279-5


. . 2.95


8741.. .


, . 8.95


8746.


. . 7,95


8749.


..9.95


8751


.29.95






Diira jicguisiTinr;


ADC0804


. . 3.49


ADCOSOB.


..695


ADCOB09


.. 395


ADC0B15.


. 14.95


ADC0817


..695


□AC0808.


.. 1.95


QAC1008.


..7.95


AY-3-1 01 50. . . .


. . 4.95


AY-5-1013A. . . .


. . 3.95



Part No.



Fur.etwn



DYNAMIC HJ1MS



Prio.



411&M-15 16\384k1 (150ns) 39

4128 131,072x1 (200ns) 455

4164N-150 65,536x1 (150ns). , ...125

4164M-200 65.536x1 (200ns) 1.19

TMS4416-12 16,384x4 (120ns) 4.95

MM5280 4096x1 (20Ons) 2107 1.95

8116 16^84x1 (120ns) (+SV Only Required) 198

41256-150 262.144x1 (150ns) 329

50464-15 65.536X4 ( 1 50ns) (4464) (41 464) 7.95

STATIC HAMS

TMM2016-12 2048X8 (120rts). 1.69

2102 1024x1 !350ns) 39

2102-2L 1024x1 1250ns) LP. (91 L02) ..1.49

2114N 1024x4 (450rs) .99

2114N-L 1024x4 (450ns) LP. 1.09

2114N-2 1024X4 (2O0rV5). , . . . , 1.05

2114N-2L 1024x4 (200ns) LP. 1,48

21C14 1024X4 (200ns) (CMOS) 49

2149 1024x4 (45ns) ....495

51 01 256 X 4 (450ns) CMOS. 395

HM6116P-3 2048x8 (150ns)CMOS 1.79

HM6116LP-3 2048x8 (150ns) LP CMOS. 135

HM6264P-12 8192x8 (120ns)CMOS 4.69

HM6264LFM2 8192x8 (120ns) LP CMOS, 4.79

HM6264P-15 6192x8 (150ns)CMOS 4.49

HM62641FM5 8192x8 (150ns) LP CMOS. 459

R614 1024 X 4 (350ns) CMOS (0PD444O) ... 4.49

PBOMS/EPflaMS

1702A 256x8 (1)i?) 3,95

270B 1 024 X 8 (450ns) , 3.95

TMS2716 2048x8 (450ns) 3 voltage. 6.49

2716 2048x8 (450ns) 2.49

27C16 2048x8 CMOS 995

2732 4096x8 (450ns) ..,...,.., 2.49

2732A-20 4096x8 (200ns) 21V. a85

2732A-45 4096x8 (450ns) 21V. 275

27G32 4096 X 8 CMOS TOS5

2758 1024x8 (450ns) Single +SV. 395

2764-20 8192x8 (20Ons)21V. , 3.95

2764A-25 8192x8 (250ns) 12.5V. 2.9S

2764-45 8192x8 (450ns) 21V. 219

27C64 8192x8 CMOS 21V. 695

27128-25 16384x8 (250ns) 128K21V. 295

27255-25 32.76S X 8 (250ns) 256K (1 25V) 7.95

27C25B-25 32,763x8 (260ns) 256K (CMOS) (1 2,5V) 1 335

68764 8192x8 (450ns) 25V 15S5

63768 8192x8 (350ns) 25V 1695

74S387 256x4 PROM O.C. 1J9

74S471 256x8 PROMTS- .,495

62S123 32x8 PROMTS. 2.95

62S129 256x4 PROM T.S_ 2BS



Part No.



LOW PROFILE [TIN] SOCKETS

1-9 10-90 100-cp



8 pin LP 13

14 pin LP. 15

16pinlP. 17

1 8 din LP. 25

20 pen LP. 28

22 pm LP. 30

24 pin LP. 31

26 pin LP. . . . 39

40 pin LP.



.12
.13
.15



8 pin WW.
10 pin WW.
14 pin WW.
16 pin WW.
18 pin WW,
20 pin WW.
22 pin WW.
24 pin WW.

28pinWW 1.39

36 pin WW. 1.49

46 .43 40 pin WW 1.78

- SDLDEHTOIL STflNDAHD (6010 J TIN] AND HEADER PIU6 SOCKETS ALSO



.29
.35
.43



WIRE WRAP SOCKETS [SOLDI IEKIL #3

1-g 10-33 100-cp



Pari No.



.55
.65
.69
.75
.85
95
99
1.19



.79

6:?
85

' 03

1 ;■?
139
1.69



?5
.75
.85
.89
,99
1.19
129
1.59



The MM5321 is a TV camera sync ganeralor oesicned to
supply (he basic sync lundioca tor either color or mono-
chrome 525 lino/60Hz interfaced and ca mera video recorder
applications, color BURST GATF, ft SYNC

ALLOW STABLE COLOR OPERATION

MM5321 $9.95

PIQITALKEBT

D n UOU — Aflplicaliont: TMChfng aid*, appliances.
docfci, lutDrnOtiv*, telccornmum L-a tio n ; . Lin g u *<&■. it a n s la -
liorti, (tic, 7Tie CT1 050 is a standard DIG ITALKER kit encoded
with 137 separate and useful wards. 2 tonea. B r>rj 5 different
gilgnce durfllioris. The wwda ind tones have been assigned
discrete add resaes, making it possible to output single words
or words concatenated jnto phrases or even sciences. Trie
""voice" oulpiji of trie DTI 0&0 ia a highly intelligible mala voice.
The DTI 054 eornists or a Speech Proceeior Chip r MM6*1 04
{40-pin) and two (2) Speech ROM-, MM52164&SR1 and
MM52T 94SSR3 (24-pin) along with a Haste; Ward list and m
;ecomnicnded schomalic diagrfljn on lh* application iheet.
ftrt hfo, Do?cripElon fi.'cc



DT1050
MM54104



CiaHanter""



$24.95
$12.95



DT1 057-Expands llie CT1050 vocabulary from 137

words to over 250 words. Includes two Q'\ ROMs and specs.



DT1 057.




. $1


1.95


NTER SIL


Pan No.


Price


Part Mo.


Prlca


FE0202D


12.95


72Q7AEV7KIL....


. . 649


FE0203D


1 2.95


721 riPL frn,), . .


..7.95


7106CPI


895


72t1MlPL (Micro;


....a49


7106EWKII.


4695


721 7kJL


10.95


7107CPI


..... 695


7217AIPL


. ,8.95


7107EV?it . .


46.9S


7224IPL


. 10.95


7207AIPO. . .


5.95


7226AEWKi5


. 99,95



74HCHI-SPEED CMOS



74HC00. . .


.... 35


74HC1 75


69


74HC0Z


.39


74HC221


1 95


74HC04


.... 39


74HC24Q


.... 139


74HC06.


.... 39


74HCZ4*.


1.49


74HC1 0.


.... 39


74HC245


. ... 159


74HC1 4.


.... .59


74HC253


.... .79


74HC30.


.... 39


74HC259


1.19


74HC32.


.... .46


74HC273.


1.79


74HC74.


45


74HC373


.... 1.49


74HC75.


69


74HC374.


.... 1.49


74HC76


69


74HC393,


....1.19


74HC85,


.... 1.19


74H0595


.... 1.95


74HC66


SO
1.19






74H0123


74HC4O40


1.19


74HC1Z5.


.99




.... .79


74HC132-


.79


74H04O50


.79


74HC138 . . .


79


74HC4060


....1.19


74HC139.


.79


74HC451 1
74HC4514




74HC1 54,


1 .95


.... 2.95


74HC163.


39


74HC453B, . . .


.... 1.95


74HC1 74


. . .89


74HC4543.


. 2.95



74C-CMOS



74C00.


29


74C1 74.


69


74C02.








74004.


.25


74C221


1.19


74G06


35


74C240


159


74010.


29


74C244


159


74C14.


.49


74C373


1.9S


74C32.


35


74C374


195


74C74, , .


.49


74C912


79S


74C65


1.19


74C915.


1.1 a


74086


29


74C920.


9.95


74C89


335


74C9?1


... 9.95




39


74C922


a95


74C154.


2.95


74C923


695


74C173.


39


74C926


4.95



□S0026CN


. . . 1.69


LM399H


. 3.95


TL074CN


- - - , .79


TL497ACN


.Z19


TL034CM


... 1j09


NE540H (C540H) .


..2.95


LM307CN


.45


NE555V


.. 29


LM309K.


1.25


XH-L555.


. .69


LM311CN.


45


LM556N


.. 3t


LM31 7T.


99


NE558N


. 1.19


LM31 aCM


.... 1.19


LM565N


.. 9?


LM31 9N


1 19


LM567V.


6fi










LM320T-5


.... 39


LM741CM


.. 25


LM323K


4.49


LM747M


.. Bi


LM324N. ......


.... 39


LM1 458CN


.. .49


LM338K.


3.95


LM14B8N


.. ,6E


LM339N


.... ,49


LM1 489N


.. ?E


LM340K-5


1,35


LM1496N.


.. .95


LM340K-12....


1.35
1 35






LM340K-1 5- . . . .


LM1872N


.2/4=


LM340T-5.


49




.XM










LM340T-15.


.... ,49


XR2206


.3.9:


LF347M


99


XR2207


-2.4C


LM348N. .....


69


XH2211....


.29t


LF351N


49


LM2907N.


. 1.9f


LF353N


.... 59


LM2917N(8pln)..


. 15!


LF355M


89


LM39O0N.


.. ,5S


LF356N


... .89


LM3905OL


I1f


LM35SN


... A9


LM3909N


.. ,K


LM360M


. . . .2.19


LM391 414


. 1.9F


LM361 Nf.


....1.59


LM391 SM


. . 19!


LM380CN


. ... 1.09


NE5532


,. ,9f


LM386N-3. ....


.... 39


NE5634.


ftf


LM387M


.... .99


75477


. . 1.11


LM393M.


.... ,45


76477


. . 3.9!



PARTIAL LISTING ? OVER 4000 COMPONENTS AND ACCESSORIES IN STOCK! ? CALL FOR QUANTITY DISCOUNTS






CIRCLE 1 14 ON FREE INFORMATION CARD




Worldwide ? Since 1974

? QUALITY COMPONENTS ? COMPETITIVE PRICING



Mail Order Elactronici ■ Worldwide



TTTT^



i-jftViiaiwmizYi



ELECTRONICS






COMMODORE COMPATIBLE
ACCESSORIES




RS232 Adapter
for VIC-20 and
Commodore 64



The JE232CM allow* connection of standard serial H3232
printara, modems, etc. to your VIC-20 and C-6fl {#? eluding
the SX-64 Portable') A 4-pola switch allows the Inversion
dI the 4 control lines. Complete installation and operalion
initructkons Inctadtd,

■ HugainlD User Fort* Provides Standard RS232 sjgnol leveij

■ Uses, 6 signals (Transmit, Receive, Cloar la Se nd, Bequest Id
Send. Data Terminal Ready, data Set Heady)

JE232CM $39.95

Voice Synthesizer VtC-20 & C-64

Plug-In — Talking in Minutes!

JE520CM $99.95

300 Baud Auto Modem
Mitey-Mo [R.rc^<) $74.95

Parallel Printer Interface

FREE 4K Buffer Included!
MW350 ^.vic-aii,c-M?c-i2Bi $69.95

TRS-80 COMPATIBLE
ACCESSORIES

E-X-P-A-N-D TRS-BO MEMORY

Al! Mb came complete with documentation

TRS-80 MODEL I, III

THS-16K3 200ns (Model III) $S.95

THS-16K4 250ns (Model I) 55,49

TRS-80 COLOR AND COLOR II

TT1S-64K.2. $11.95

New models only —
TBS-CoCo-lncl. 2-50464't (4i464'?), . . . S19.95

TRS-80 MODEL 4, 4P

TBS-64K-2, $11.95

E xpands Model 4 ff cm 1 GK - 64 K or Model 4 P from G4K- 1 2BK

TRS-64K-2PAL. $29.95

Expands Model 4 Irani 64K to f 28K

TRS-80 Model 100 < NEC * OLIivetti

M100BK. $29.95 m. or 3 tor $79.95

TRS-BO Model 100 Expansion

NECBKR S29.9S M. or 3 for $79.95

NEC Model PC-8201 * Expansion

OM108K. $29.95 u. or3 for $79.95

CHIwIti Model Ml Expansion

TANDY 200

M2D0R $99.95 es or 2 tar $189.95

Tandy Model 200 Expansipn

PROMETHEUS MODEMS



S



Intelligent

1200/300 Baud

Modem with

Real Time
Clock/Calendar



The ProModem" is a Bell 21 2A {1200/300) intelligent stand,
alone modem - Hayes command set compatible plus an ad-
ditional extended command set * Shown wilh alphanumeric
display option RS-232 Stand-Alone Unit;

PM1200 $299.95

Options for ProModem 1200

PM-COM $79.95

ProCofn Communications Sotrwa re Please specify Ocerali ng
System - Apple:f*oDOSorCP/M - I8M PC COS or MS DOS

PM-OPS12K. $129.95

Communications Buffer Option

BUF512K. $54.95

512K Memory for PM-OP512K

PM-ALP. $79.95

Alphanumeric Display lor ProModem 1200

PM-SPECIAL #2 $249.95

Includes PM-0P512K. BUF512K and FM-ALP



APPLE' COMPATIBLE ACCESSORIES

All Apple Cards come complete with instructions. MADE IN THE USA!



16K RAM CARD
(Language Card)
For Apple! and II+*



Expand Irom 48K-64K. Buns
ApplaSott. DOS. CPfto and
Pascal [AHC-loTCHEM 1)

JE860" . . S39.95



CONTROLLER
CARD

For Apple II, ll-f-andffe'




Capable of handling up 10 two
drrvas. Recommended drives:
ADD-51J or AOD-12. (ACC-1)

JE875.... $49.95



EXTENDED 80-
COLUMN CARD

For Apple Me'




JEH64 is en extended 80-
column/64KRAM Card.Uflra-
niQh resolution capability

JE864 .- .. $69.95




128K RAM CARD

For Apple ii. II ■ and its'

Four key software program! are Included:

Utilities. Diagnostics. Demos, and RAM
Draft Emulators fa* DOS 3.3, CP/M and
Apple Pascal Expand-A-RAM:

JE868" $119.95



fflfffMimmiK




APPLESURANCE

DIAGNOSTIC DISK

CONTROLLER CARD

For Apple II, II+ and Me'

PRsTVEFiTS CRASHES!

Tesl your BAM, ROM, CPU and Disk Drives
DHV-1/Applesurence II:

JE877 $69.95



(gfljcwinmis




PARALLEL
PRINTER CARD

For Applet II, 11+ and /to"
Fully compatible wilh Annie CP'M, Apple
Pascal far FORTRAN], and most diner op-
erai rrg systems and software p acka ges.
Avaitable for Apple El, 11+- and ?a'. WrT-1:

JE880 $59.95



Sm^ciitiMib-




PARALLEL/SERIAL 64K
BUFFER CARD

For Apple II, H+ and We*

Using (ne parallel jumper cable supplied.
Ihe JE.S83 will attach fo the JE350 jabove}.
Parallel Card needed tor operation Tito
JESS3 Includes a standard parallel Inpul
wilh both parallel Hind serial {RS232} oul-
fered outputa, P/S l~



JE883 $79.95



'APPLE, APPLE II. II- and Me are registered trademarks or Apple Computers.
"When using CP/H, the .IE (SO end JE860 will only (unction with verskm 2 JO or earlier: PASCAL
(JE861J Version 1.1 or MrikK

ADDITIONAL APPLE* COMPATIBLE PRODUCTS

Key: e -Apple II or II+ b = Apple lie

APF-1 Cooling Fan with Surge Protection ■ Key: |a,t>) $ 39.95

KHP4007 Switching Power Supply ? Key: (Kb) S 39.95

JEG14 Humerie/Aux. Keypad ■ 1 1 acceulbta functions - Key: lb). ... $ 49.95

AM ON 12' Green Monitor with Swivel Stand * Key: (e. b end flc)- . . . - $ 99,95

KB-EA1 Apple Keyboard and Case.. Key: (a) S 99.95

JE520AP voice Synlhs*i? - Plug-In, User Ready - Key; (*.t? $119.95

ADD-12 E'r Matr-Height Disk Drive - Key: (aM. 5129.95

ADD-llc 5 u- Hair-Height Disk Drwa - Key: (?c) $129.95

ADD-514 bW Full Height Disk Drive ■ Key: (a,b|, 51 39.95

PM1 200A Promrrlheus Intnrnel Modem - 2 Cards - Key: ia.bi S299.95

PM1200M Promatneua Macintosh Em, Modem ■ Key: IMaclntoshi $349.95

GENERAL APPLICATION POWER SUPPLIES

Power/Mate Corp. REGULATED POWER SUPPLY

-Input: 1u5-t25/2i0-2S0vACe47-63Hi- Line regulation: '- O.Q5As - 3 mounting

surtaces - Overvoltage protection - UL recoflnited ? CSA cartitiad

Part Ho. Oumut Sin [Inchee) Waigtit PRICE



EMA5/EB
EMA5/6C



5Ve3A/6Vel2.5A
5VS6Ar6Ve5A



■i" 3 L . - H .W . 2'iK
5*sL 1 4'sW X 2'sH



2 lbs. ?29-95

4 lbs S39.9S



4-CHANNEL SWITCHING POWER SUPPLY

| ■ M icroprocessor, minicomputer, lerminal, medical equiomenl and process con-
trol applications - Input: 90-1 30VAC. 47-4JUHi ■ Output: ^5VDC ? 5A, -SVDC

I etA:+t2vTX!?1A,-!2VDCeiA-Unereo.ulallon: : 0.2%. ffipplo- SOmVp-c
- Load regulallon: -- 1 'Ha - Ovcrcurrent protection - Adjustment Sv mom output
* 10? *Siie: S^T. k 1tl'W):4-15/16"H ? waigtit: n lbs

FCS-604A $59.95



IBM' COMPATIBLE
ACCESSORIES



J ~~JLU aeeL I DUjtj



83-KEY KEYBOARD



-Identical layout as original IBM PC Keyboard - Highly
desiraoie case *nth palm rest ■ Complete with cable and data
■JUST HUG INI

KB83 $49.95

Build an IBM PC/XT- Compatible 1 .

IBM-G4K 64* kaii o-.cs ?ii $ 10.49

KB-83 93-Key Keyboard $ 49.95

IBM-FCC Floppy Controller Card. ... $ 59.95

IBM-Case Case $ 59.95

ISM-MCC Monochrome Card. $ 89.95

IBM-PS Power Supply, $ 99.95

FD55B Disk Drive. $11 9.95

IBM-MON Monochrome Monitor. . . . $109.95

IBM-MB MoUrerboend S269.95

Regular List $870.09

rBM?-SpeCJal UneL 9 then. above) ■ . $749.95

IBM PC/XT

Equivalent

130 Watt

Power Supply

Upgrade Your PC!

■ Input: 1 1 0V e SOHe - Output: +5VDC 8 1 5A, -5VDC S 0.SA.
+12VLX: ? 4.2A, -12vtX) S 0.5A -Pluo compatible con-
nectors - Fits inlo IBM PC - weight: 5 lbs.

IBM-PS $99.95





IBM
Compatible!
DISK DRIVES

Documentation



FDS5B Teec S%' DS ts-Helghl $1 19,95

SA455 ShuDJrt &i ■? ds ' ...Height $1 1 9.95

TM1 00-2 -tendon 5W DS Full-HelglH. . . . $119.95

JMR 5Y4" DISK DRIVE ENCLOSURES

Complete with power supply, 5wi1c h.
power cord, fusehotoer and connecton.

DDE-1FH $69.95

Houses 1 Full-Height 5^ ' Floppy Drive

DDE-2HH $79.95

Houses 2 Hall-Heigtit 5 n 4' Floppy Drives - Vertical

HDDE-1FH $199.95

Houses- i Hard Oaak Drive

UV-EPROM ERASER -

^ —



?k



Eraies all EPRQMa. Erases up to B chips whttiin 21 minute*
(1 chip in 1 5 n,irngi*jrj) . rvtatntair>3 constanl expoaure distance
of r Specal conductive team liner Mirmnales static burld-up.
Bum -m safety look to prevent UV exposure Go-mpacE- S.QQ L
x 3 70^ x 2 60"H Complete with hewing tray for a chips.

DE-4 UV-EPflOM Eraser. . , . $74.95

UVS-11EL Replacement Bulb. . . . $17.95



DATA BOOKS



30003 National Linear Data Book (H2) Si 4.95

30009 Initnii Date Book tB5 r S 9.95

30013 Slog Data B-Mk fG5|. ...... . , $14.95

30022 Nan Logic Data Book Set {84) $24.95

210830 Inlel Memory Handbook ,33/84, S 19.95

230343 Inlel Microsystem Hndbk. (83/8*1- - . . $19.95

MUFFIN/SPRITE-STYLE FANS



MUF60 (3PH3-15-24e2) .... S9.9S

Howard Industries (4.68' sq , 60 cfm)

SU2C7 $9.95

EGaG Rotron (3.1 25' square, 20 cfm)




$20 Minimum Order - U.S. Funds Only
Shipping: Add 5% plus $1.50 Insurance



Send stamped,

self-addressed envelope

fo receive a Quarterly

Sales Flyer - FREE!

5/86



California Residents: Add 6°/o or 6V2% Sales Tax




Spec. Sheets - 30C each
Prices Subject to Change

Send S1.00 Postage for a

FREE

1986 JAMECO

CATALOG



1355 SHOREWAY ROAD, BELMONT, CA 94002 ? PHONE ORDERS WELCOME 415-592-8097 Telex: 176043



CIRCLE 114 ON FREE INFORMATION CARD



GREAT PRICES! GUARANTEED 100%



74X1

741 XX

742xx

743XX

74LSxx

74LS1XX

74U2xx

74Ls3xx

74Fxx

74F1xx

74F2xx

74F3XX

74HCTXX

74HCT1XX

74HCT2xx

74HCT3XX



? ? ? CALL TOLL FREE (800) 245-8555 ? * ?

DIGITAL IC SPECIALS



74 SERIES

20 74Sxx

.30 74S1XX

.35 74S2XX

,40 74S3xx

.20 74ALSXX

.30 74ALS1XX

40 74ALS2XX

.45 74ALS3XX

.25 74HCxx

.35 74HC1XX

50 74HC2xx

.55 74HC3XX

.30 74SCxx

.40 74SC1XX

55 74SC2xx

.65 74SC3XX



CMOS
any 4000 series
any 4500 series



2.5 mhz

cpu. ctc. pio

DMA, DART, StO
4.0mhz (A)

cpu. ctc. pio
dma, dart. sio

6.0mhz (B)

CPU, CTC, PIO
DMA, DART, SIO



.75
1.95



1.50
3.95



2.50
6.95



Any 65xx

Any 66 XX
Any 68Axx



6500 / 6600 Series
1.50 Any 65xxA



1.50
2.25



Any 65xxB
Any 6fiBxx



200
2.75
295



74LS0O
74LS11
74LS74



74LS1S3

74LS139



74LS240
74LS257
74LS283
74LS373



Your Choice .17 ea.

74LS02 74LS08 74LS10

74LS20 74LS30 74LS32

74LS109

Your Choice 22 ea.

74LS157 74LS161 74LS138
74 LSI 74 74LS166 74LS175

Your Choice .29 ea.

74LS241 74LS244 74LS245

74LS273 74LS279 74LS280

74LS368 74LS367 74LS393

74LS374 74LS377



64k dram

Set of 9

200ns $8.99

150ns $9.99

256k dram 150ns

Set of 9
29.95



"RAMS**



2101

2102

2016-20

2016-15

2111

2112

2114-2

2114-3

2114-4

2116

2147

4044-4



256x4

1KX1

2Kx8

2Kx8

256x4

256x4

1Kx4

1Kx4

1Kx4

16Kx1

4x1

■IK:- i



Sialic
Sialic
Sialic
Sialic
Sialic
Sialic
Sialic
Sialic
Sialic
Sialic
Sialic
Sialic



450ns

450ns

200ns

150ns

450ns

450ns

200ns

300ns

450ns

150ns

55 ns

450na



.39

.39

.95

1.45

1.65

.75

.37

.35

.32

.49

1.49

.45



4044-2

MK4118

TMS4027

UPD411

MM5280

6116-4

6116-3

4116-2

4116-25

6264LP-15



4KX1

1KxB

4Kx1

4Kx1

4Kx1

2KxB

2Kx8

16Kxi

16Kx1

8Kx8



Static

Static

Static

Static

Static

Sialic

Stalic

Dynamic

Dynamic

Stalic



2O0ns
250ns
250ns
300ns
300ns
200ns
150ns
200ns
250ns
150ns



.75
.75
.25
.69
.45
.95

1.25
.29
.25

4.75



2708

2716-

2716-3

2716-2

2732

2732-3

2732-3

2764

2764-3

2764-2

27128

27128-3

271&8-2

27256



E-Proms

1Kx8

2Kx8

2Kx8

2Kx8

4Kx8

4Kx8

4Kx8

BKx3

8Kx8

8Kx8
16KX8
16KX8
16Kx8
32KX6



450ns
450ns
350ns
250ns
450ns
350ns
250ns
450ns
350ns
250 ns
350ns
300ns
200ns
250ns



.55
.95
1.25
1.55
1.25
1.45
1.75
1.75
1.95
2.25
2.75
2.95
3.15
7.95



**CUT LEAD IC PROGRAM**



These IC's are cut lead types -
= Used in IBM Clone Mother Boards



Useable in PC Boards or Sockets****



any @ .12 ea.



7400

7414

74174

7430

7486

LS1 12

LS164

LS240

LS283

LS393



7402

74146

74175

7432

7475

"LS138
LS165
LS241
LS298

?LS670



7403
74153
7491
74367
7489
LS139
LS166
?LS244
*LS30
?LS74



7404
74157
74193
74368
7493
*LS14

LS169
?LS245
*LS32
LS86



7406
7416
741 95
74368
7493

*LS14
LS169
LS251
LS365

*S00



?7407
74160
74221
74393

*LS02
LS1S3
LSI 75
LS253
LS367
S04



7408
74161
7426
7440
LS03
LS1S5
LS131
LS257
LS37
*S138



7410
74163
7426
7442
*LS04
LS1S6
LS193
LS266
?LS374
*S157



74109
74165
7427
7445
LS05
LS157
LS194
■LS27
LS375
S161



7411
74166
74276
7451
*LS08
LS158
LS195
LS273
LS377
S240



74123
7417
74279
7473

"LS10
LS161

■LS20
LS279
LS378
S241



74125
74173
74298
7474

LSI 07
LS163
LS221
LS2B0
LS38
*S74



8000':
8031
8035
8039
1NS8060
IMS8073
8080A
8035
8085A-2
8036
8086-2
8087-3
8087-2
8088



3.95
2.95
245
9.95
9.95
.70
3.95
995
4.50
5.25
129.95
169.95
6.95
8089 29.95

8100'S

8131 2.45

8155 2.45

8155-2 2.75

6156 5.90

8185 19.95

6185-2 29.95



B200's
8202
8203
8205
8212
8214
8216
8224
8226
8226
8237
8238
8243
8250
8251
8251 A
8253
8253-5



9.95
19.95
2.50
.90
.95
,90
1.90
1.90
2.20
2,90
2.35
1,25
3.70
1.75
1.85
1.75
1.75



8255

8255-5

8257

8259

8271

8272

8274

8275

8279

8282

8283

8284

8266

8287

8288

8289

6292



1.75
1.75
1.75
1.75
39.96
3.95
8.95
8.95
2.50
2.95
5.95
2.45
3.45
5.95
3.95
3.95
9.95



8303

8304
8307
8308
6310
9311



8300' s



2.70
1.70
2.70
2.70

3.50
3.50



8741 7.95

8748 7.95

8749 7.95
8755 16.95



1691
1771
1791
1793
1795
1797
2143
2791
2793



6845

6847

68645

7220

8275



DISC CONTROLLERS
5.95 2795



4.50
4.95
8.95
9.95
9.95
6.95
12.95
12.95



2797
6843
8272
MB8876

MBB877
MC3470
UP D 765



CRT CONTROLLERS
1,75 CRT5057



9.50
6.95
12.95
8.95



CRTS037

DP8350
MC1372

TMS9918A



19.95
19.95
12.95

?| ALL ITEMS

LOU

SUBJECT
? TO PRIOR

1.95
14.95



SALE!



SPEED UP YOUR IBM BY 33%

New V-20 CPU Mta. by NEC replaces

tne 8088 in your system
Nc compatibility problem.



$15,95



IBM GLOME

MOTHER BOARD IC COMPLEMef^T

SOOO'* DIGITALS




BIOS ROM

for $9.97
M? CLONE Mother Boards



■OH

■m

ns

D97

noa

Djghul* 74 s#

MSW l

74S7J 1

74S137 1

MS13* i

7*&w 2



74DT

!*!><; HON

7+15373

74LS323

74tS2X4

74LSS15

7U22T

74132Q

74LS13B

74iaoa



74L5175
T41SS2

TilSX]



Whon Purchase Individually $99.00
SPECIAL $79.9S (or Entire Sat olSC's



* MISCELLANEOUS IC SPECIALS



TR1602

WD1100

MC1776CPI

MC12002L

AV5-1013

IMS1420-

MC145S

MC1488

MCI 489

AM2167

MN27580

26I.S31

26LS32

2651P2

SCM266IA



.95
.65
.65
.65

95
.75
.22
.26

.26
,75
.55

19
19

.65
.75



2652

02817

2901 PC

2910PC

D3232

MK38B7N

C04CKM

C04011

C04013

C04019

CD4025

TMS4027

TMS4050

THS4060

CD4042



.65
.95
.95
.95
.65
.95
.17
.17
.19
.19
19
29
.19
19
.19



C 04049

C 04077

CD4081

MM5262

NE555

ME 5 56

SY6520

HM6116

HM6147

TL0-S2

ST6545

MC6810

MCS845

UA709CP

7545 IBP



19
.19
.19
.19
.19
.39
.79
.75
.29
.19
.95
.35
.79

19
.19



75454


.19


Tt.0-71


19


CDM8017


.95


N8T25


.19


P8254-2


.95


NB2S115T


.95


DPa?41f,


.95


8692


m


zarxnAOC


as


CRT9006


95


CRT90C7


.35


CRT9212


.95


MC10104P


.65


AM9602


.29


TMS9937


.95


AM9517M


.95



ELECTRONIC PARTS OUTLET

2515 N. Scottsdale Road
ScottSdale, A2 B5257 (602) 941-9357

(SEND FOR OUR FREE CATALOGUE)

TOLL FREE!!

CALL (BOO) 245-6555



In Phoenix, AZ

ELECTRONICS PARTS OUTLET

1921 C W. Thunderbird
Phoenix, A Z 85023
602-375-0181 ,2



In Florida

ELECTRONICS PARTS OUTLET

2275 So. Federal Hway
DelRay Beach, FL 33444
305-265-1206 ,7



BTk r>3m noMd iff t PU oi \nMj be dtonl t. jm by In rod mannff. m Friri E^nt StnJjrt At $ JSOfl. a RaHy Ore ff *n M



^^^^^ **NOW3 RETAIL LOCATIONS AND MORE TO COME**
CIRCLE 252 ON FREE INFORMATION CARD



BQ



THE FIRST NAME IN



ELECTRONIC TEST GEAR




Save s 30 on the
RAMSEY 20MHz
Dual Trace
Oscilloscope

Unsurpassed quality al an
unbeatable pries, the
Ramsey oscilloscope com-
pares to others costing
hundreds more. Features
include a component test-
ing circuit for resistor,
capacitor, digital circuit and diode testing ■ TV video sync filter ? wide band-
width & high sensitivity * internal graticule ? front panel trace rotator ? Zaxis
? high sensitivity x-y mode " regulated power supply " built-in calibrator ?
rock solid triggering _ j _ _, _, _ _ ,.

S O O irt Q *S High quality hoot ?n

Was S3&9.95 NOW ONLY^OOSJ 5 " P rob? incited




NEW RAMSEY
1200 VOM

MULTITESTER



Chech transistors, diodes and LEDs
with this professional quality meter.
Other features include, dacibei scale ■
20K volt metering system * 3Vi' J mir-
rored scale ■ polarity switch * 20
measuring ranges ? safety probes ?
high impact plastic case




rm



*19?5



teal leads and
battery included



RAMSEY D-4 100
COMPACT
DIGITAL
MULTITESTER

Compact sized reh ability and accuracy.
This LCD digital mulhtester easily fits in
your pocket, you can take it anywhere.
It features full overload protection ? 31*
digit LCD readout ? recessed input
jacks ? safety probes * diode check
(unction ? 2000 hours battery life



*22 95



I e si leadi and
tatlery included



MINI KITS— EASY TO ASSEMBLE, FUN TO USE

BEGINNERS & PROS WILL HAVE A GREAT

TIME WITH THESE KITS



FM
MINI

MIKE






A super h;gn performance FMwiira*
ig?5 mike fell 1 Trsmsmls a Stable
srgrnal up to 300 yards wlrt erccp-
Hor-al audio quality Dy m&antof ill
built in eleclrei mike. Kit includes
case, mike, or-yN switch, antenna,
baltery and su per instructions. T bis
>5 the finest unit available
FM-3 Kit ?14.95

FM-3 W?red and Tested 19.9S



FM Wireless Mike Kit

Tansm?il5 up to 300' fo
any FM broadcast r&-
dm uses any lype of
mike. Runs on 3 fo SV Type FM-2

has added sensitive nuke praam p

stage

FM-T Kil $3.95 FM-2 Kil 54.95



wi Kit

Provides ihe basic parts anc? PC
beard required to provide a source
at precision liming And pulse
general ion. Uses 555 inner IC and;
includes a range of parts, for mosl
liming needs
UT-5 Kit 55.95



Color Organ
See music come
ahve 1 3 different
lights flicker with
music. One ''9 nE
each for. high,
mid-range and
lows Each indi-
vidually adjust-
able and drives up
to 300 W. runs on
11GVAC-

Complete kit,
ML-1
S8.95



Cs-ivfrn i any TV Id video rnowio* Sum
UPWe. lunabln- ewer ch *■& Rum on 5-
15V KC*plltld irirjEfl.*iQnal Hell *HI <W
inc.-rirlel' Cc-mpltiefcn VD-l it *S



Led B I inky Kil
A great attention get-
ler wtijch alternately
flaanesJ^mooLEDs
Us* for name bwjpes .
buttons, warning

Sanel I ighis, anything i
unson3fo TSvoHs.
Complete k\ I, BL-t
S2JG




Super Sleulb
A iLppr se n si1 ive arnpti -
liar Wit. t; will p c* up a
pindfopet iSfeeti Great
for monitoring baby's
room or as general pur*
pose ampFiTier Full ?:'■?
rms OUtpul. runs on 6 lo
fS voJls, uses SMS olim
Speaker.
Complete kil. SM-9

SS95



CPO-1

Runs on 3-12 Voc i wall oul, 1 KHZ good lor CPO.
Alarm, Audio Oscillator. Complele kil S2.95



Whisper Light Kit

An interesting kil, small mike
picks up sounds and converts
!'ium to light. The louder the
sound, the brighter the light.
Includes mike, controls up lo
3DO W. runs on 110 VAC

Complete kit, WL-i
$6.35



Mad B Easter Kit

Produces LOUD earshaitertng and
.altenlion getting siren like sound
Can supply up lo 15 walls ol

obnoKtouiaudia nunson6-l5VOC



MB-i Kit



54.35



Ton* Oecoder
,A complete lone deco-
der on a single PC
board. Features; 400-
5G0Q Hz adjustable''
range via 20 turn pot. votiage rtgu-
lanon. 557 IC. Useful lor toucb'
lone burst detecuon. FSK, etc
Can also be used as a stable tone
encoder. Runs on 5 to 1 2 volts
Complete kiLTD-1 ?5.35



Siren Kit
Produces upward and downward
wail characteristic ol a police
siren. 5 W peak audio OUlput. runs
on 3-15 volts, uses 3-45 ohm
speaker.
Complete kil. SM-3 J2.?



HtaTmBju
Sum tw *■ 14 VOC to" C'j'ff.i ;?itji n
mtaMann atfti'*ty tq-t km ts.so

TB-rAuy ?.?



3aWatt2mtrPWRAMP

Simple Class C power amp leelures times power gain, t W
In For B out, 2 W in lor 15 due. 4 W in Tor 30 out. Max output
ol 35 w, incredible value, complete with all parts, Less case
and T-R relay. *#?#*&*

PAi, 30 W pwr amp kit *22 B3

TFt-i. rf sensed t-r relay kit



695



Power Supply Kit

Complele Iriple regulaled powisr
supply provides variable 5 to 16 volts
ol 200 me and j 5 al t Amp. Excellent
load regulation, oood filtering and
small size. Less iranslormers,
requ i res & 3 V i a i a and * ?* nc
24VCT complete km PS-3LT W 5J



H71



35 MHz DUAL TRACE OSCILLOSCOPE




A heavy duty and accurate scope for service

as well as production use. Features include

? wide frequency bandwidth ? optimal sen-
sitivity * extremely bright display ? delayed
triggering sweep ? hofd Off ? ALT trigger *
single sweep ? TV sync ? 5X magnification

? XY or XVZ operation ? HF/LF noise
reduction

3500 Dual Trace Oscilloscope



S49995



includes 2 high
quality probci



ALL OSCILLOSCOPES INCLUDE Z PROBES



FT?!



15 MHz DUAL TRACE PORTABLE OSCILLOSCOPE

Ideal for lield/bench applications, this
scope can display up lo 15 MHz signals.
Internal battery pack allows up to 2
hours operation on a single charge,
Features include ? built-in battery
charger ? 5X horizonlal magnification
? high brightness CRT ? front panel
trace rotator ? internal rechargeable




? [ battery pack

^a**^2S00 Portable Oscilloscope

include* 2 nigh
quality probe*



\S4499 5





MINI-100 FREQUENCY COUNTER

Fealure^andcapabililies of counters coaling iwiceas mucti *
compact * high sensitivity ? low Current dram ■ very accurate *
leading ;ero blanking ? held or shop use * 1 MHz lo 500 MHi

range ■ diode protected ■ 7 digit display

BATTERY CHARGER NICAD BATTERIES
AND AC ADAPTER INCLUDED



S9995




CT-70 7 DIGIT 525 MHz
COUNTER

Lab quality al a. breakEri rough price. Features ■
3 frequency ranges each wilh pre amp ? dual
selDctahlagate limes ? gate activity indicator ?
50mV@ 15Q MHz typical Sensitivity ? wide 1re-
quency range ? 1 ppm accuracy

S "4 H Q95 wirsd includes
■ ^ AC *dtpler



CT-70hM SS9.95

RP-4 nicad pack *.95

CT-50 8 DIGIT 600 MHz
COUNTER -^ ^_? =

*169 95 .? M

CT-50 kit I1&9.95

RA-i receiver adapter kit H.95



CT-90 9 DIGIT 600 MHz
COUNTER

The mosl versatile lor less 1han $300. Features 3
selectable gate times ? 9 digits * gate indicator

? display hold ? JfimV @ 150 MHr typtcal sen-

siiiwity * 10 MHz limerjase for WWV calibration

* I ppm accuracy

^1 4Q95 wlred includei
■ ^ ^ AC adapter

CT-90 kil ?129.95

OV-t t PPM Qv*m ttmebase 59,t5

BP-< mead pack &.S5

CT-125 9 DIGIT 1.2 GHz
COUNTER

S 4 C Q 9 5 -'?'"■ ' incluiln

BP-4 nicad S3.9S




DM-700 DIGITAL MULTIMETER




Professional quality aj a hobbyist price Fea-
tures include 36 drMerenl ranges and" 5 lunc-
tions ? 3'; digil. 1* inert LED display * aulo-
n^atic dBcsmB^placerrient ? automalic polarity
wired include;
AC adapter

□M-700 kn M9.S5

MP-1 probe sea . 4.95



ii'ui-l w\. i.'lII ;.i,M.i-;:iif




PR-2 COUNTER PREAMP

The PP.-2 \i ideal tar measuring weak stgnals
rrom 10 to 1 ,000 MHi ? Hat 25 db gam ? BNC
connectors ? great (or shiltrng RF ? ideal
receiver/TV preamp

Sj% Jl. 95 *> red Include!
^W T AC adapter

PR-2 fcit 534.95



PS-2 AUDIO MULT1PUER



The PS-2 is handy tot myn resoiutton audio
resolution measurements, multiplies Up in in. 1
cjuancy ? great lor PL lone measurements *
multiples by lo or 1DO * O.Qi Hz resolution ?
built-in signal preamp/condilioner




$4995



PS-10B1.5GHzPRESCALEH

E?[*rkJs lh? range of your [traunl counter to I S
GHz ■ 2 stags eieamp * divide by 10>DO circuil-
iy * super sensitive t5Q ntV ypicai] ■ BN0 eon-
neclws * I GHz at 1 MHz nut * drrva -i-v OQurtliif



PS 10-8 Prescaler

? : i'f ? indudn tC adipitT



*7995



ACCESSORIES FOR RAMSEY COUNTERS

Telescopic whip antenna— BNC plug , r S 3,95
High impedance probe, light loading . 16.9S

Low pass probe, audio use 1E.95

Direct probe, general purpose use 13.9S

Tilt bail, tor CT-70, 90, 1Z5 3.95



PHONE ORDERS CALL

716-586-3950

TELEX 466735 RAMSEY CI



TERMS: ? satis! action guaranteed ? examine lor ID days: il rial pleased, return In
original lorm lor reltind * add 6*. (or shipping and insurance In a maximum el
S10 OD ? overseas add lb lor surlaco mail ? COO add S2.S0 1C0D in USA oniyl
? orders under S15 0D add SI 50 ? K1 residents add 7' s sales tax ? SO day pans
warranty on all kits ■ 1 year parts & labor warranty on all wired units

I = ====—== I RAMSEY ELECTRONICS. INC.

1= J1.I?I^? Y 2575 Bai rd """?

— — I Penfield, N.Y. 14626



>

-<



CO

en



CIRCLE 70 OH FREE INFORMATION CARD



117



ADVERTISING INDEX



RADIO-ELECTRONICS does not assume any responsibility for errors that may appear in the index below.



Free Information Number



Page



269
108
76



107

72

84

77

S3

98

251

274

265

266



264
27S
54

79
280



A.I.S. Satellite 79

AMC Sales 8

APProducts 24

Ad Mart CD6

Advanced Electronics ....27

All Electronics 99

Amazing Devices ; .-, , ;. 102

American Design Components 110

Appliance Service .79

B&K Precision .14

BUYUS 79

Beckman Industrial 82

Becktron 20

Blue Star Industries , . 79

Boardworks 84

C & S Sales .39

C.O.M.B 12,29

CIE ...34

Caig Laboratories 86

Cameo Enterprises 79

Chemtronics 87

Command Productions 84

Communications Electronics 3,33

Cook's Institute 8



268

127

270

95

82

252

277

120

111,253

100

254



271

86

59

113,255,

256,257

25S

114

115



Coop's Satellite Digest 81 —

Copper Electronics 87 258

Deco Industries .79 87

Delta Electronics 102 259

Dick Smith Electronics 92,93 —

Digi-Key 113 267

Digital Research Computers 100 272

Electronic Parts Outlet . 1 16 117

Electronics Book Club 23 —

Electronics Technology Today CD10 278,279

Elephant Electronics 79 281

Etronix 9.82 —

Fireslikll 82 260

Fluke Manufacturing 7 276

Fordham Radio CV4 126

Grantham College of Engineering .... 41 —

HW Sams 2S,40 78

Hameg 25 70

Heath 26 261

JDR Instruments 13 75

JDR Microdevices 104, 105 262

JDR Microdevices 106, 107 282

JDR Microdevices LOS 263

Jameco 1 14,1 15 103

Jensen Tools 79



Joseph Electronics 42

J&W 101

MCM Electronics 109

Mark V. Electronics 112

McGraw Hill Book Club 52

Mercer CV3

Micro-Marl 96

Mouser ........,,,.,,. 9

NRI 16

O.K. Industries 8,9

Omnitron .22

Pacific Cable 97

Probemaster 15

Prof. Diving School of N.Y. 86

RAG Electronics 5

RCAD&SP 11,31

Radio Shack 1 1 1

Ramsey 117

Saratoga Electronics 98

Spartan Electronics 118

Tektronix CV2

Toroid Corp. of Maryland 30

U.S. Instrument Rentals 21

Wm B. Allen 103



Gernsback Publications, Inc.
500-B Bi-Counly Blvd.
Farmingdale, NY 11735
(516) 293-3000
President: Larry Steckler
Vice President: Cathy Steckler

For Advertising ONLY 516-293-3000
Larry Sleekier

publisher
Arline Fishman

advertising coordinator
Shelli Weinman

advertising associate
lisa Strassman

credit manager
Donna Sala

credit associate
Christina Eslrada

advertising assistant

SALES OFFICES
EAST/SOUTHEAST
Stanley Levitan
Eastern Sales Manager
Radio-Electronics
259-23 57th Avenue
Little Neck, NY 11362
718-428-6037, 516-293-3000

M I D W ESTTexas/ A rkansa s/Okla .

Ralph Bergen

Midwest Sales Manager

Radio-Electronics

540 Frontage Road— Suite 339

Northfield, IL 60093

312-446-1444

PACIFIC COAST/ Mountain States

Marvin Green

Pacific Sales Manager

Radio-Electronics

15335 Morrison St.— Suite 227

Sherman Oaks, CA 91403

818-986-2001



O

Z

o
rx

F-
O



6

<

rx



(516) 499-9500

6094 Jericho Tpke.

Commack, N.Y. 11725



WELLER Temperature
Controlled Soldering
Station _,.
Wi



S97.95



? Control Ranges BQ0R 7aoF. 800 F

? Change temperature by simply
changing [he heat sensing lip

? Sale Ear IC Soldering

■ Storage Tray tor extra Lips and tip
cleaning sponge with receptacle

? Comes wilh 1*" screwdriver Lip 700 F.
? 3 wire 4.5' long cord



NEW 12"

DIAGONAL

MONITOR



[ * Monochrome display
1 Composite video
80 characters & 25 lines
700 line resolution at cenler
Non-glare CRT




SGL WABER DATAGARD
Spike & Noise
Suppressor

$37.95




PROTECT YOUR COM
PUTER WITH DATAGARD



Dalagard DG115S provides a single-stage
spike lilEcr and a single-stage noise filter
to prelect against moderate and cata-
strophic spikes and virl pally all unwanted
noise inlerelerence coming through the
wail outlet




Green

$90.95

Amber

$95.95



HAYES
Smartmodem 1200



$390.95



? Full or Half Duplex

? 300 BPS or up to 1200 BPS operation

? Auto Answer and Auto Dial

? Connects directly to telephone lines




XCELITE



$33.00




Multipurpose fourteen piece nut
and screwdriver set



RS232 TRANSMISSION
LINE TESTER,

$18.95

Features: "Hale to Female connector for
easy insertion into RS232 Line "Test 7
Lines (TD, RD. FfTS, CIS, DSR. CD. DTR)

using LEDs to indicate status of each
'Directly powered by RSJ32 Line no AC
power needed.




GENERAL INSTRUMENT
58 Channel Remote
Controller

LCC-58




? On/off fine tune

? Wireless

? installs in minutes




PHILIPS REMOTE CABLE
CONVERTER



$121.95



■ Micro computer letnmogy * Quartz

conLrrjlSrrrJ. iC's lock in pmiurtr & prevent

drift ? GO channel seieciion ? Prop.ramrria1)le

lime on & oil ? 24 hour LED digital

doc* ? Favorite channel memory & recall plus.

scan * Wireless hand held "infra-red"

Iransmitter system ? Automate fine

tune ■ Adaptable to any brand

television * One year warranty Hrwx



Dealers Welcome

Prices subtest to change without
notice COD S2.Q0 Extra

We accept NIC Visa Amci CODtw SKI
deposit! Sliippiiiu. cliaigos as luitows

to 75 00 S2 Ml

76 00 to 2W 00 t - ■■■ ■

251 00 to 500 00 SB 00

501 00 to 750 00 sa SO

751 00 to 1000 DO $12 00

Over 1000 00 SI? SO

Store Hours:

Mon-Fri 9-6 Sal. 9:30-5

(516} 499-9500

TELEX: 551427 SPARTAN



CIRCLE 75 ON FREE INFORMATION CARD



118




MODEL 9401

4 V2 -digit, full function,
hand-held DMM with
.05% accuracy and
data hold
i 129 ?



MODEL 9701

dlgi-clamp? compact

AC clamp-on volt-ohm-
ammeter wilh data hold

S 69 M



mercer

ELECTRONICS

Division a/ Simpson Electric Company

859 Dundee Avenue, Elgin, IL 60120-3090
(312) 697-2265 ? Telex 72-2416




Mercer Electronics products reflect the design and quality
standards established by Simpson Electric Company, an industry
leader for over 50 years and known worldwide for its integrity
and product excellence.

In Stock. . .Available Now! Stop in at your nearest distributor
and see this new, complete line of Mercer test instruments.
For the name of the MERCER distributor in your area, call
(312) 697-2265, or send for our new line catalog.

CIRCLE 267 ON FREE INFORMATION CARD




Model DCM-602

$6995

3 1 /i Digit Capacitance Meter

8 ranges with full scale values to 2000 uF
FEATURES ? Broad test range - 1 pF to
2000 uF ? LSI circuit provides high
reliability and durability ? Lower power
consumption ? Crystal time base

? Protected from charged capacitors

? Frequency range - 800 Hz to 8 Hz



$48 75



$7995



7 functions, 32 ranges.
Transistor measurement
included.



1 1 functions, 38 ranges.
Includes logic level detector,
audible visual continuity,
capacitance and conductance

measurement.

3V2 Digital Multimeters

FEATURES ? DC Voltage 100 uV - 1000 V ? AC Voltage 100
200 uA - 10 Amps ? Resistance 20 Megohms ? Capacitance
? Overload Protection ? Auto-decimal LCD readout ? Polarity
battery life with 9V transistor battery ? Low battery indication



Model DVM-636

$62 75

8 functions, 37 ranges.
Capacitance measurement
included.



uV - 750 V ? AC/DC Current
(DVM 636/638) 1 pF ? 20 uF

indication * 300 hour



ASK FOH FREE CATALOG.

Money orders, checks accepted. CO.D.'s require 25% deposit.

Fordham

260 Motor Parkway, Hauppauge, NY 11788



Toll Free

800-645-9518

In NY State 800-832-1446



Service & Shipping Charge


Schedule


Continental U.S.A.




FOR ORDERS


ADD


S25-51Q0


S4.50


S101-S250


S6.00


S2 5 1-500


sa.oo


S5O1-7S0 ....


S1O6O


S75 1-1.000 . .


sia.so


S1 ,001 -1500


S 16.50


S1.5OI-200O .. .


. S20.00


S2.O01 andUo.


S250O