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The entire line is advance -engineered by RCA to meet rigid performance standards. RCA's all- solid -state circuitry provides dependable trouble -free performance. Protection against lightning induced voltage surges is provided in all amplifiers. All passive devices designed for low insertion loss.

All housings have RCA's "new -look styling" in molded high IMPAC@ plastic cabinets. Similar styling design for all models presents a uniform appearance for a complete line. Installation convenience ... mounting is simplified with the use of the new RCA "slip -on" clamps. No solder connections are required to connect any model into a system. Serrated washers simplify connecting 300 -ohm line to the devices. All hardware, complete installation instructions and system wiring connectors are included with every model.

INDEX

Multi -Set Couplers 3 Band Separators (Back of Set) 5 (Wall Mount) 7 Matching Transformers 8 Antenna Couplers 9 Interference Filters and Traps 11 Wall Outlets and Plugs 13 Preamplifiers 16 Distribution Amplifiers 24 Typical Distribution Systems 31

E RE-2 RCA Parts and Accessories Distribution Services This is how to get it. 2000 Clements Bridge Road Deptford, New Jersey 08096 The RCA Antenna Systems Accessories Catalog is Please send me a free copy of the RCA the TV service dealer's complete guide to better Antenna Systems Accessories Catalog. reception for his customers and more sales. So tune in and get your free copy today with absolutely no Name obligation. Ask your local RCA Parts and Accessories distributor how to get Business Phone your free copy, or fill out and Rail Address mail the attached coupon. City State Zip

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YES, I want you to mail to me without obligation, the FREE DEMONSTRATION LESSON and com- Credit towards a Certified Electronic Technician plete literature on the career program checked (C.E.T.) rating will be granted by the National below. (Please check one.) Electronics Association to ICS students upon completion of the ICS Career Program in TV Color TV Servicing FCC License Service /Repair. Computer Communications/ Maintenance Broadcasting CATV Installation Hi -Fi Sound Systems Telephony Industrial Electronics O ELECTRICIAN

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Approved for veterans under the new GI bill /approved for federally insured loans/ Canadian residents use above address for State Zip Accredited by the Accrediting Commission service from ICS Canadian, Ltd. In Hawaii of the National Home Study Council. use Peat Office Bos 118, Honolulu. L J Circle 2 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 1

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www.americanradiohistory.com Radio -Electronics. F O R M E N WITH I D E A S I N ELECTRONICS

February 1973

SEMICONDUCTOR DIRECTORY, SPECIAL 35 Inside The IC Digital Clock planned for this issue will ap- See how the one -chip IC used in a digital clock works. FEATURES pear in March. See p. 100. by Larry Sullivan

39 Multifaceted World Of Infrared What's happening and how it affects modern electronics. by Forest Mims

BUILD ONE 51 Grinchwal Mainframe Readout 11q by Don OF THESE Lancaster THIS MSI IC made by Mostek is just about for a digital clock. 54 Low -Cost Keyboards the complete electronics learn how it works turn to page 35 Make your own custom design for less than 25 cents a To key. by Don Lancaster RETURN SPRING 58 IC Breadboard -Using The Digl Designer Build a simple computer by Jack Cares T OP 69 Build Dual- Function Photometer PANEL It's easy to build and handy to own. by Harold Pallatz DAMPING PAD

GENERAL 4 Editorial ELECTRONICS The whole truth. 3s 6 Looking Ahead Tomorrow's news today. by David Lachenbruch 26 Equipment Report Aries pocket calculator kit. PLATED PC CONTACT CARBON 32 Equipment Report PANEL KEYSTEM URETHANE Onkyo TX -666 stereo receiver. CONSTRUCTION DETAILS of a keyboard switch you can build for less than 25 cents. 60 State Of Solid State turn to page 54 New developments in solid -state electronics today. by Lou Garner Hugo Gernsback (1884 -1967) founder M. Harvey Gernsback, editor -In -cl .el and publisher 43 Dual -Trace Triggered Sweep Scopes Larry Steckler, editor, CET TEST Robert F. Scott, W2PWG technical editor. CET How they work and how you can use them. EQUIPMENT Jack Darr, service editor. CET by Forest Mims Louis E. Garner, Jr., semiconductor editor I. Queen, editorial associate Matthew Mandl, contributing editor David Lachenbruch, contributing editor TELEVISION 62 Step -By -Step Troubleshooting Charts James A. Gupton, Jr., photographic electronics by Art Margolis Vincent P. Cicenia, production manager The agc amplifier. Nancy Gipson, production assistant H. Matysko, circulation 71 TV Service Clinic Troubleshooting intermittents. by Jack Darr Cover photograph by Walter Herstatt Cover design by Marius Trinque 78 Reader Questions Radio -Electronics is indexed in Ap- R -E's Service Editor solves reader problems. plied Science & Technology Index and Readers Guide to Periodical Literature. 22 Letters 100 Next Month DEPARTMENTS Radlo- Electronics, February 1973. Vol n_, No. 2 Published monthly nV Gernsback Pubi,oabons. Inc.. 200 Park Avenue South. New York 12 New & Timely 90 Try This t.ay 10003 Second -class postage paid at New York. N. Y. and adds. tonal mailing office. One-year subscription rate- USA U.S. posses. sons and Canada. $7. Pan-American courtines. $8. Other countries. 96 New Books 98 Noteworthy Circuits se 50 Single copies 60e ©1973 by Gernsback Publications, Inc All rights reserved Printed in U.S A. 86 New Literature 111 Reader Service Card Subscription Service: Mail all subscription orders, changes. correspondence and Postmaster Notices of undelivered copes (Form 35791 82 New Products 102 Technotes .o Radio -Electronics Subscription Service, Boulder. Colo 80302

FEBRUARY 1973 RADIO -ELECTRONICS 3

www.americanradiohistory.com editorial

the whole story

In the letters column this month, you will find a detailed message from Frank Moch, executive director of NATESA (National Alliance of Television and Electronic Service Associations). It's addressed to Bess Myerson and is concerned with the practices used by consumer protection groups to check out TV service technicians.

Frank Moch's letter, coupled with a recent newspaper story in New York City, has prompted this editorial. A few months ago New York's daily newspapers carried a story that told of a check run on eight TV repair shops. It specified how seven of the eight shops checked proved to have a dishonest operation. The implication was that the TV set owner in New York City had only one chance in eight of finding an honest shop to get his set working.

Concerned by the article, we checked with the consumer protection agency and obtained a copy of their complete report. In reading the report, including the fine print, we found that it was true that seven of the eight shops were dishonest. But -and this is the key to the whole thing -the seven dishonest shops were selected on the basis of numerous prior complaints.

Therefore, this was not a random sampling and should not have appeared to be representative of the entire TV service industry in the city. Unfortunately, the qualifying remark was located near the bottom of the report and apparently was not noted by all of the newspapers who picked up the item.

All professions harbor small number of dishonest businessmen. But to distort and paint every TV service technician as a dishonest operator is a terrible injustice. The vast majority of TV service technicians are honest, hard -working businessmen -men who are really concerned with repairing a set and returning it in good shape to their customer as soon as possible and with as reasonable a fee as possible.

We call on all consumer protection agencies and news reporting media to be much more careful in how they fling their statements about. By all means, we do want to see the dishonest operator put out of business. But, unfortunately, the dishonest operation has considerable legal protection while the honest operator appears to be wide open to take the rap for the dishonest minority.

When reporting on any TV service operation, we ask that the media be sure to get the whole story in the first paragraph of their report every time. And wouldn't it be different, if just once, the typical honest technician was in the news? --Larry Steckler, Editor

4 RADIO-ELECTRONICS FEBRUARY 1973

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www.americanradiohistory.com looking ahead

Another firm, affiliated logical follow -up might be a tern, which is finding many Narrowcasting with Microband, has signed kit which lets you paint your uses in education, industry up most of the current appli- own loudspeaker by numbers. and commerce. Sony has That word is the opposite cants for MDS service to affi- produced about 40,000 of of broadcasting. And it de- liation contracts, so that na- these, selling most of them in scribes the new Multipoint tionwide televised meetings The videoplayer market the United States, and ex- Distribution Service (MDS) may be held. The affiliates pects to make about 100,000 authorized by the FCC and would receive the program The first cassette videotape this year. In the United expected to go into service material by microwave, com- recorders designed exclu- States, a record -and -play U- early this year. MDS is a munications satellite or air - sively for the home are now Matic costs $1,395 and a commercial service designed expressed videotapes. In ad- on sale in most major mar- playback -only unit is $995. to provide low -cost visual dition to business meetings, kets throughout the United The principal attraction of the communications between a Microband says its services States and Canada. Sold un- Sony unit is its operational central point in a metropolitan will be used for ethnic pro- der the brand names of Admi- simplicity and reliability. Al- area and several receiving lo- gramming to community cen- ral, Emerson, Montgomery though the U -Matic isn't com- cations for private or semi- ters, religious services to Ward, Sears and Teledyne patible with either the Cartri- private use. The FCC has set churches and pay -TV movies Packard Bell, they all use the vision or the upcoming aside the 2150 to 2160 -MHz to motels. The FCC is cur- Cartrivision deck, manufac- Selecta- Vision system, Sony portion of the spectrum for rently considering whether to tured by Cartridge Television feels that it will become the MDS, allotting one channel assign a second MDS chan- Inc. A network of sales and consumer standard. However, per area. nel to the current service. It rental outlets for pre- recorded Sony officials say a real mar- Under the MDS system, appears to be the start of a programming is now being ket for a home U -Matic won't the local FCC licensee estab- new nationwide TV intercom assembled. The first Cartrivi- come for another five years - lishes a central transmitting service -or, as Microband sion models are all 25 -inch by which time mass produc- point in an area and sells puts it, "hundreds of private color sets with built -in tion and integrated circuitry time to local businesses TV networks." recorder -players and sell at a will have reduced the cost of which wish to transmit pic- relatively steep $1300 to a record -play unit to about tures to various points within $1600, with a black- and -white $500. By that time, Sony fore- a 15 to 25 -mile radius. Small Talking pictures camera about $250 extra. sees sales of at least a mil- parabolic antennas are in- At these prices, obviously, lion units per year. stalled at the receiving loca- You have a couple of this is not yet a mass -market tions. The transmitted signals beautiful art masterpieces on product, but the manufacturer may be digitally encoded so your wall, see? And you turn of decks is just starting up Midget digits that specific program time on the stereo. Suddenly you and couldn't fill huge orders. segments may be received get fantastic sound, with no Toward the end of 1972, it's A new electronic watch only by the locations for apparent speakers in evi- estimated that perhaps 5,000 circuit that is small enough to which they were intended. dence. It's your paintings try- units had been shipped to be incorporated into a petite For example, if Coca -Cola is ing to tell you something. dealers, and total orders by ladies' watch, or to permit the sponsoring a televised sales That's the latest audio prod- manufacturers for the decks addition of an automatic cal- meeting from 2:30 to 3 PM uct from Fisher Radio. The came to about 15,000. Later endar, is being designed by and Pepsi -Cola a meeting patented "Sound Panels" ac- this year, some manufacturers the Inselek Corporation of from 3 to 3:30, neither loca- tually are flat speakers mas- will introduce a stand -alone Princeton, N.J., under con- tion would be able to spy on querading as paintings. But playback -only Cartrivision tract to Optel, Inc., of the the other's sales message. unlike some flat speakers, deck for attachment to any same city. Microband Corporation of these are claimed to be supe- color set at about $700. At the heart of the circuit America, which has received rior to acoustic -suspension That's the same price is a newly designed "silicon - the first permit for such ser- types in efficiency and sound which RCA projects for its on- sapphire" (SOS) IC, to be vice, in Washington, D.C., dispersion, and equal in fre- MagTape Selecta- Vision play - used in combination with a and has applied for licenses quency response. Each and- record deck, which has a liquid -crystal digital display. in 32 other cities, is promot- speaker has two drivers at- built -in digital clock -timer so The SOS circuit is claimed to ing MDS as the lowest -cost tached to the rear of an ex- that programs may be re- be smaller, more accurate form of visual communica- panded polymer diaphragm. corded when the set owner and lower in cost than the tions available- cheaper than The diaphragm radiates en- isn't home. This is scheduled conventional all- silicon ICs. videocassettes or even movie ergy over its entire surface, to come on the market late The target for marketing the projection. If 10 or more dispersing sound in a 360 -de- this year. It's not compatible first SOS watches is late this viewers watch in a single lo- gree pattern. Eight different with the Cartrivision unit, of year. Price of the new time- cation, Microband says, it paintings, or "Sound Panels," course. pieces has not yet been de- should cost less than a dollar are being offered, at about However, the most suc- termined by the manufacturer. per viewer for each 25- minute $138 each. The paintings are cessful videocassette re- program presented twice on fabric -you can't use one corder isn't a home unit at by DAVID LACHENBRUCH weekly on a year's contract. of your own pictures. The all, but Sony's U -Matic sys- CONTRIBUTING EDITOR

6 RADIO-ELECTRONICS FEBRUARY 1973

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FEBRUARY 1973 RADIO -ELECTRONICS 11

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Electronic tranquility machine mental light switch, for switching a beam relieves headaches, insomnia of laser light. Scientists have been seek- An electronic "tranquility machine" ing such a switch as part of future elec- that relieves nervous tension and quickly tro-optical systems that would transmit cures many types of headaches, was large amounts of information over light demonstrated at the 58th annual conven- beams. tion of the Jewish women's service orga- The switch is an yttrium gallium nization, Hadassah. The device was de- scandium garnet film, about 2.5 microns veloped by scientists of the Electro- thick, grown on a gadolinum garnet sub- Sleep Clinic of the Hadassah- Hebrew strate. It is the center wafer in the photo- university in Tel Aviv, Israel. It is about graph. It acts as a waveguide for light - the size of a large transistor radio. waves, two types of which, the TM No description of the electronic op- (transverse magnetic fields) and TE eration of the instrument was given at (transverse electric fields) can pass the convention. It appears to be a form through it. The wafer also carries a zig- of the electronic sleep instruments devel- zag (serpentine) electric circuit, which oped by researchers in the United States sets up a tiny magnetic field when cur- and Russia, as well as in Israel. As de- rent passes through it. scribed, it is milder in its effects than the electronic sleep instruments; it is said to produce a state of relaxation "bordering on sleep." THREE CYLINDERS OF PLUTONIUM 238 pro- ASE R Some headaches not curable by vide the energy for the cryogenic 'fridge, BEAM drugs have been successfully treated which cools things down to more than 300 with the machine. On the other hand, degrees below zero. The young lady Inserting the tubes Is Pamela Gleason of Hughes' according to Dr. Fiorella Magora of the cryogenic department. GARNET CIRCUIT University, some persons simply do not fllM respond to it. Not only have headaches SCHEMATIC DRAWING of the light switch, showing how the output waves are separated. and insomnia been successfully treated, But vehicles such as spacecraft of- but general tension usually yields to the ten have no electrical power to spare, machine, and it has been effective in al- and this first nuclear unit, using radio The wafer is positioned between two lergic asthma and certain types of mi- isotopes, therefore has important advan- prisms that couple the light beam into graine. tages. Three small capsules of Plutonium and out of it. The exit prism guides the Five years experience with the de- 238 are all that is required to produce beam in one direction if it is a TM type vice, states Dr. Magora, have shown de- the super -cooling. of lightwave and in a slightly different di- cisively that its benefits have no detri- It may seem odd to use heat to pro- rection if it is of the TE type. mental side effects. This makes it duce cold, but the principle has been Light is fed into the input prism in possible for the patient to use it at used in home gas refrigerators, such as the TM mode, and passes across the home, simply placing three electrodes on the old Norge ( "Cools with Heat! "). The wafer, over the serpentine circuit, and the head, pushing the starting switch heat evaporates a liquid, which absorbs out via the exit prism. When current is and setting a timer to turn off the in- heat as it returns to the liquid state. passed through the circuit, the beam is strument when the desired time of treat- changed from TM to TE, and thus fol- ment has been completed. New laser -beam light switch lows a different path on leaving the has future in electronoptics prism than does the light passed when Airborne nuclear refrigerator Bell Laboratories scientists have de- the serpentine circuit is switched off. cools to -320 F. veloped and demonstrated an experi- This makes it possible to code informa- A nuclear cryogenic refrigerator that tion into the beam. produces temperatures as low as -196 Bell scientists see the possibility of C ( -320 F or 77 K) has been demon- many improvements over the present ex- strated at the Mound Laboratories of Mi- perimental device. These may result in amisburg, Ohio. It was developed for the simplifying it to a very small thin film and Atomic Energy Commission by Hughes a tiny electric circuit, without the com- Aircraft Co. paratively bulky prisms. Such low temperatures are needed to cool infrared and other sensors to Sixth amateur radio satellite temperatures at which they reach their has several new features greatest sensitivity. Earlier units, using OSCAR VI (Orbiting Satellite Carrying electricity as a source of the heat energy Amateur Radio) recently sent into space FILM that may THE THIN LIGHT SWITCH be NASA Delta space rocket from that activates these refrigerators, have part of future optical circuits for putting aboard a been used successfully in space, air and phone calls and data on a light beam. Pencil the Western Test Range in California, dif- ground systems. points the path of the light wave. (eontinued on page /4)

12 RADIO -ELECTRONICS FEBRUARY 1973

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www.americanradiohistory.com FREE new G I e l (continued from page 12) send now for the all new t y 'son 1973 CATALOG fers from the five previous Oscars in sev- cations are impossible because of the eral important respects. distances and rugged terrain, ordinary Using batteries rechargeable by the radio communication is often unreliable, sun, its life is expected to be at least a and television is non -existent. year. It operates in a circular polar orbit 900 miles from Earth. It receives amateur Laser beam used in new signals on 2 meters and retransmits them image transmission system in the 10 -meter band, thus permitting in- By using a laser beam to burn thou- ternational communication on frequencies sands of holes in a thin bismuth coating heretofore limited to short-range opera- over a transparent plastic film, Bell Labs tion, by many more amateurs than before, scientists have devised a way of making this includes many hams in developing microfilm copies of photographs, printed countries who have not previously had any copy or other graphic material trans- opportunity for experience with space mitted from distant points. communication via satellite. OSCAR VI is also expected to offer greater opportunities to schools to provide laboratory experience in several aspects of space science. Three of NASA's "Spacemobiles" which visit schools for demonstration purposes will be equipped for OSCAR VI use. Coordinating arrangements for the NASA launch is AMSAT Your Savings Guide to -the Amateur THE WORD "THE" is made by leaving areas Radio Satellite Corporation -a volunteer untouched by the laser beam, while burning Everything in Electronics group of radio amateurs headquartered off practically all the bismuth on other parts in Washington, DC. The official tracking of the film. Individual holes may be seen around the borders of the Individual letters. Here's your NEW and complete station will be operated by a group of annual buying guide to: By simply reversing the modulation signal, hams at the Talcott Mountain Science the THE could also be white letters on black Everything in audio & hi -fi background. Tape recorders & accessories Center in Avon, Connecticut. Radios & phonos of all kinds New build -your-own kits First domestic satellite The system uses a laser beam Auto electronics & accessories Citizens Band two -way radios is launched in Canada pulsed at a million pulses per second, to VHF & UHF police /fire monitors Anik, the world's first domestic com- burn holes in a bismuth coating less Amateur & shortwave radio Electronic security equipment munications satellite, went into orbit No- than three millionths of an inch thick, TV-FM antennas Test gear vember 9 last, to tie all Canada together deposited on a transparent Mylar plastic. Books, parts bargains, tubes, transistors, wire, more! in one communications network. In an Portions of the plastic not touched by equatorial orbit 22,300 miles above the laser beam block 99 per cent of any NOW! Send for the only catalog Earth, it can "see" all of Canada from incident light; the holes pass 80 per cent with a wide selection of Newfoundland to the Yukon -Alaska bor- of the light falling on them. THE BEST OF THE FAMOUS BRANDS der-a distance about 1,000 miles As shown in the photograph, the OLSON EXCLUSIVES! greater than that from New York to San holes are formed in a dot pattern some- See special products Francisco -and from the United States what like a halftone photograph in this & values sold only by boundary to points in the far north where magazine. The laser beam is scanned Olson including our broadcast listeners hear Moscow and across the film by a small vibrating mir- all -new TELEDYNE Berlin better than they do Toronto and ror to make the rows of boles. If no stereo line. Montreal. power is applied to the beam, the bis- Many full -color pages! Anik (which means "brother" in Es- muth is left intact. As power is varied, Olson Electronics kimo) will carry at least three television the beam burns larger or smaller holes. 1 channels, two in English and one in Thus a wide range of gray tones can be rOlson Electronics Dept. LC French, and a multiplicity of communica- produced. The film can be used in a 260 S. Forge St., Akron, Ohio 44327 tions channels, including telephone and slide projector to make a large image on D Send FREE 1973 Olson catalog data transmission. Telesat Canada, a pri- a movie screen. Either printed pages or Name Apt vate- public corporation created by the reproductions of photographs can be Address Canadian Parliament, already has 13 projected. City customers, including the Canadian The system may make possible a State Zip Broadcasting Corp. and the Bell Tele- high- speed, low -cost terminal for receiv- Name Apt phone Co. of Canada. ing data from a computer, or for obtain- Address One of the main objectives of the ing information from remote files or City new system is to serve the far north and records. A typical newspaper page can !State Zip J the Artic islands where wire communi- (continued on page 16) Circle 6 on reader service card 14 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com tarn Your Electronics DEGREE Attl by studying "117%,, a ^ d% i at home.

Grantham School of Engineering specializes in teaching electronics and supporting subjects, mainly by corespondence. The School is authorized under the laws of the State of California to grant aca- demic degrees, and is approved under the G. I. Bill.

The A.S. E.T. Degree is offered in four "correspondence semesters" plus a two -week residential semi- nar. Then, the B.S. E. E. Degree is obtainable through further residential training in engineering subjects and transfer credits in the humanities. For complete information, write for our free BULLETIN R -73. GRANTHAM School of Engineering 1505 N. Western Avenue Hollywood, CA 90027

Circle 7 on reader service card FEBRUARY 1973 RADIO- ELECTRONICS 15

www.americanradiohistory.com Either way (continued from page 14 new & t i me' 1 you get the y world's first universal four -channel be transmitted in four seconds over a First TV repair co -op high- capacity transmission channel, or in Now open in New York City The decoder. about four minutes over an ordinary tele- Grand Street Consumers Cooperative phone line. Society is new. R -E Special report next month.

BBC 1922/1972

EVR -4X4 Four -Channel AM /FM Receiver EVX -44 BBC 1922/1972 $249.95 Universal Four -Channel Decoder $99.95 owJ

Now Electro -Voice offers our new universal decoder circuit built into both a stereo receiver and a 74P 4- channel decoder. FOUR BRITISH STAMPS COMMEMORATE the 50th anniversary of broadcasting by the British The EVR -4X4 Receiver has Broadcasting Co. and the 75th anniversary of the experiments by Marconi and George Kemp that every needed feature for 2- and resulted in the successful radio test over water in 1897. The 3 -penny stamp shows six types of microphones used in broadcasting from 1922 to the present. The 5 -penny stamp pictures the Am- 4- channel sound. Yet it costs no plion loudspeaker, famous in the mid- '20's. A modern television camera is featured on the 71/4- more than many 2- channel units penny stamp, and the 9 -penny stamp shows radio equipment used in 1897 for the 9 -mile trans- that offer half the pleasure. And it mission across Bristol Channel. R -f will properly decode any matrix 4- channel input without switching. Radio -Electronics is published by Gerns- back Publications, Inc. 200 Park Ave. S. Ideal for playing SQ *, Stereo -4t, New,York, N.Y. 10003 (212) 777 -6400 MOVING? or any other matrixed records, tape, President: M. Harvey Gernsback or FM sources. Secretary: Bertina Baer Don't miss a The EVX -44 Universal Decoder single copy of creates a 4-channel control center ADVERTISING SALES EAST Radio -Elec- for existing stereo equipment. Just Stanley Levitan, Eastern Safes Mgr. tronics. Give and two ATTACH add a second stereo amp Radio -Electronics us: more speakers. Unique separation 200 Park Ave. South LABEL enhancement circuit automatically New York, N.Y. 10003 (212) 777 -6400 Six weeks' no- adjusts front -back separation as HERE tice required by program material. MIDWEST /Texas /Arkansas/Okla. Ralph Bergen Both the receiver and the decoder The Ralph Bergen Co. Your old ad- are also designed to accommodate 6319 N. Central Ave. dress and zip `discrete' inputs like 8 -track tape if Chicago, Ill. 60646 you wish. Hear the finest in four - (312) 792 -3646 code channel sound at your Electro -Voic s PACIFIC COAST /Mountain States Your new ad- showroom. Where the excitement is! Jay Eisenberg dress and zip E -Y 4- channel products are produced J.E. Publishers Representative Co., under U.S. Patent No. 3,632,886 8560 Sunset Blvd., code C8S, Inc. Suite 601, tT,M. Electro- VO/ce, Inc. Los Angeles, Calif. 90069 (213) 659 -3810 name (please print) 420 Market St., San Francisco, Calif. 94111 (415) 981 -4527 address

SOUTHEAST city state zip code E. Lucian Neff Associates 25 Castle Harbor Isle, Mail to: Radio -Electronics ELECTRO- VOICE, INC., DEPT. 234E Fort Lauderdale, Florida 33308 SUBSCRIPTION DEPT., BOULDER, COLO. 613 Cecil Street, Buchanan, Michigan 49107 80302 In Europe: Eleelro. Voice, S. A., Rdmerstrasse 09, 2560 Nidee. Switzerland (305) 566 -5656 r Ca ^ada: EV of Canada, Ltd., Ontario Circle 8 on reader service card 16 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com 51,000 replacements can't be wrong when you go by the book.

Gives the data you need to replace today's most used solid -state devices with only 156 RCA SK s. For example, RF and Video stages. Add to this a SK 3004, alone, replaces over 4,000 types. full line of diodes and broad coverage of ICs and you see why so many service technicians go the SK way. It's "The Solid State System" that re- RCA's "SK Replacement Guide "" is and trouble when the device you duces your inventory needs and the book to go by when you need a want to replace is not identifiable. builds customer satisfaction. solid -state replacement. It not only You can be sure the devices that Contact your RCA Distributor to- cross - references the top -quality SK SKs replace so easily are not merely line with over 51,000 types, both the off -beat kind. They're the ones day for the full SK story, and get the foreign and domestic, but also sup- you are most likely to encounter in latest copy of the RCA SK Replace- plies the kind of specific application your everyday servicing work. For ment Guide SPG -202N. You'll see information you need to choose the example, the SK line not only offers why you can't go wrong with RCA best replacement. It even includes a the largest variety of matched audio SKs. comprehensive Quick Selection Re- pairs but also provides full coverage RCA I Electronic Components placement Chart to save you time of TV deflection systems as well as Harrison, N.J. 07029.

Electronic RC,' Components

Series Lr Fu"tt ot tte Ron Circle 9 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 17

www.americanradiohistory.com Changes come fast in electronics.

From tube to LSI

Take a look at the race in circuit technology. In the ahead with NTS Home Training! You get the latest, 1960's the tubes at the left made way for the transis- most advanced equipment (at no extra cost). More tors at the right. Today, transistors are surpassed by solid -state units, and more advanced technology. the large scale integrated circuit (LSI) at the far right. Plenty of training with integrated circuits, too! As an This circuit, less than a quarter inch square, replaces NTS graduate, you enter a world of electronics you're over 6000 transistors! familiar with. You have a thorough working knowl- There's big money to be made by the men who edge of solid -state circuitry. You're ready to tackle stay ahead of this technology race. Put yourself bigger jobs at higher pay!

NTS COLOR AND B &W and all other equipment are yours grated circuits! All Solid- State! You to keep. perform all wiring and patchcord- TV SERVICING i ing. No shortcuts. No pre -wired circuit boards.Your training is com- Solid -state plete! Also receive an FET Volt - B & W TV, Ohmmeter and a 5" wide -band Solid -state 74 sq. in. Solid -State Oscilloscope. 315 sq. in. io picture (cabinet NTS ELECTRONICS Heath color TV included) COMMUNICATIONS Gain the prestige and earning power of owning an F.C.C. First Class Radio -Telephone License. Two NTS ELECTRONICS Build and keep the largest, most comprehensive NTS courses cover advanced color TV made! Over -all & COMPUTER the big opportunity field of trans- solid -state design, ultra -rectangular TECHNOLOGY mitting and receiving. screen, matrix picture tube, built -in You build and keep 14 kits, includ- self- servicing features, "Instant Build and keep this exclusive NTS ing this amateur phone 6 -meter On," A.F.T., solid- state, 24- channel Compu- Trainer. It teaches you the VHF Transceiver, NTS's exclusive detent UHF /VHF power tuning, and 6- transistor Solid -State Radio, and much more! Also build and keep Solid -state a fully transistorized Volt- Ohmme- AM -SW Radio, Solid -State Radio, Compu- Trainer ter. Also, learn 2 -way radio, Citi- FET Volt- Ohmmeter, and Electronic 14 integrated zens Band microwaves, and radar. Tube Tester. Learn trouble- shoot- circuits replace 198 transistors! ing, hi -fi, stereo, multiplex systems, radio, color and B &W TV servicing. 5 -watt AM transmitter/ Learn sophisticated solid -state cir- receiver cuitry as you build this B & W TV receiver. Lo -Silho "Superhet" Radio, FET Volt- Ohmmeter, Solid - State Radio, Electronic Tube same principles used in million - Checker, and Signal Generator. TV dollar systems. Contains 14 inte-

18 RADIO-ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com NTS Home Training puts you in the lead.

NTS INDUSTRIAL & decks, stereo multiplex component Radio. Prepare yourself for great AUTOMATION systems, and more! Set up a spec- opportunities in the Home Enter- ELECTRONICS tacular music system. Learn about tainment Industry! Automation is the future of indus- Build and keep this CLASSROOM TRAINING try and you can play an important famous Heath Stereo AT LOS ANGELES part! Learn industrial controls by Receiver and Speakers. You can take classroom training at Los training on the NTS Electro -Lab (a Angeles in sunny Southern California. complete workshop). You also build NTS occupies a city block with over a and operate this 5" million dollars in technical facilities. Solid -State oscillo- Check box in coupon below. scope. And you perform experiments that involve regulat- NATIONAL ß SCHOOLS ing motor speeds, WORLD -WIDE TRAINING SINCE 1905 temperature, pres- Resident & Home Study Schools sure, liquid level, 4000 S. Figueroa Street and much more. All Los Angeles, California 90037 equipment is yours to keep. APPROVED sound distortion, amplification and NTS AUDIO ELEC- control, loudspeaker baffles, prob- FOR VETERANS TRONICS SERVICING lems of system installation, etc. In- Accredited Member: National Associa- Learn basic sound theory -how it cluded is Volt- Ohmmeter, In- Circuit tion of Trade and Technical Schools; works in home radio, car tape Transistor Tester, and Solid -State National Home Study Council. ;¡$.. r N'S Dept. 206.0231 CODF L I MASTER COURSE IN COLOR I Big, Colorful NTS F+CTNpry¡CS TV SERVICING Guide to new 1 COLOR TV SERVICING (FOR NAME AGE opportunities in ADVANCED TECHNICIANS) I Electronics. MASTER COURSE IN B &W TV & RADIO SERVICING ADDRESS -_ I Yours FREE! L MASTER COURSE IN I ELECTRONIC COMMUNICATIONS PRACTICAL RADIO SERVICING CITY ------I NATIONAL TECHNICAL SCHOOLS FCC LICENSE COURSE I 4000 S. Figueroa Street MASTER COURSE IN ELECTRONICS TECHNOLOGY STATE ZIP I Los Angeles, California 90037 Please rush me FREE Color NTS Elec- AUTOMATION & INDUSTRIAL ELECTRONICS Check if interested in Veterans Training I tronics & FREE plus in- Guide lesson, COMPUTER ELECTRONICS under new G.I. Bill. formation on course checked at right. I BASIC ELECTRONICS Check if interested ONLY in Classroom No obligation. No salesman will call. Training at Los Angeles I AUDIO ELECTRONICS SERVICING L J FEBRUARY 1973 RADIO -ELECTRONICS 21

www.americanradiohistory.com What maltes letters Crown products UNIQUE ?

People often ask us what makes Crown products OPEN LETTER Third, service of ALL sets of neces- so different. To begin with, Crown is a profes- FOR ALL SERVICE TECHNICIANS sity is a custom operation because of sional audio equipment manufacturer, although a variety we also serve discriminating audiophiles. Then We are becoming very concerned multiplicity of models, and great there are other unique differences which you may with attitudes of many elected persons of trouble symptoms, many of which can not be aware of. on consumer problems. It quite obviously be caused by a number of distinctly dif- Crown craftsmen work to only one quality has the "in to cast blan- ferent troubles. This work can be per- level. Models differ in size and features but not become thing" quality. Each is designed to be superior in overall ket condemnation upon entire phases of formed properly only by well trained performance in its price range. For example, no business. We hear at accelerating in- technicians, all of whose costs are competitive amplifier, preamplifier or tape re- cidence, references by these people to based upon American standards rather corder can match Crown's distortion levels. Crown depressed stan- products are made only in America, by American ALL TV -radio service people being rack- than Oriental or other craftsmen with 99% American parts. eteers. Were this to be a fact, at least dards. Every Crown is guaranteed to meet or exceed we could take consolation in a posh life Fourth are the myths that the defec- printed specifications. Ratings given are always while driven from bank to tive product is small or was bought at a for minimum performance levels. For example, style being the DC300 is rated at 150 watts per channel rms bank by our chauffeurs in our Cadillacs. bargain. These factors actually add to at 8 ohms, although it typically delivers 300 watts The most galling new aspect is justi- cost of service because smallness con- per channel rms with 4 ohms. fication of any and all rash charges by gests circuitry and cheap price is due to Each active electronic component is tested re- before wiring, then each circuit board is tested the politicos, with the statement, "Bess "stripping down" of components and after wiring, and finally, the complete product is Myerson said so." This classic hiding duction in safety tolerances. tested from every angle. All in all, a tape recorder behind a skirt by elected officials, using A major unfair tactic by exposé undergoes more than 100 hours cumulative test- unfair and non -productive tactics, is shoppers is allegation of overcharging ing. Finally, every Crown is accompanied by its individual hand -entered proof -of- performance quite abhorrent and cannot be tolerated. for estimates. This is compounded by report. The enclosed letter to Miss Myerson shoppers who use marginal products All this in -plant effort is backed up in the field we hope will give her information on and often "cutely" try to confuse the by broad -service warranties. This is not to make of the products "look good" in advertising, but be- facts of TV service business life that will servicer by their explanation symp- cause we feel committed to keeping every product eliminate excuses for the would -be do- toms, even though the injected planted serving its owner satisfactorily. Amplifiers and gooders. evidence may be as simple as a blown preamplifiers are covered by a three -year war- Miss Bess Myerson fuse, which trouble if legitimate, could ranty on parts, labor and round -trip shipping. In addition, all warranties cover continuous com- Department of Consumer Affairs be due to major but possibly intermittent mercial usage, including broadcast use 18 hours a 80 Lafayette Street multiple component breakdown. The day, 7 days a week for years. This is extremely New York, New York 10013 point generally missed is that a true esti- rare for hi fi products, but it confirms the fact that Crown products are designed to the profes- Dear Miss Myerson: mate actually entails an entire correction sional standards demanded by recording studios, We are getting from consumerism operation, often requiring at least tempo- research and design laboratories, professional oriented elected officials what we are rary installation of replacement com- musicians, etc. of your statements. ponents to verify correction or to move Among the professional features which ensure sure are distortions the least possible deterioration are front panels We speak only for the TV -home electron- on past one defect to analyze a second. of 3/16" aluminum plate, corrosion -protected ics servicer. The usual approach is that The degree of service performed de- metal parts, wear -proof control markings, silicon almost all TV -radio technicians are to- pends on the servicer's desire to restore transistors, tantalum capacitors, and many other top -grade components selected for maximum life. tally dishonest and then in lieu of per- a set to as close to like-new condition, Crown does not plan for product obsolescence. sonal investigation, they try to justify which in many cases, might be beyond The design lifetime of a Crown recorder is ten their statements by saying in effect, the set owner's ability to recall because years or 65,000 hours, with three service over- "Bess Myerson says so." sets, like auto tires, WEAR OUT gradu- hauls. We have not yet found performance deterioration in any amplifier after six years in the field. This we believe is a perversion of ally. As one of the oldest audio manufacturers what you are trying to do and serves NO 95% of servicers recognize the set selling in the high fidelity market, we at Crown honest purpose. owners' right to determine how far resto- emphasize that our primary goal is not to make and so if the set sales, but to serve our customers as we would When a person without knowledge ration should proceed want to be served, with factual advertising, of a given business dealing with a highly owner says "Just make it work," the genuine product value and courteous customer complex product, attempts to arbitrarily cost is far less than a full restoration. service. For us, this is a deeply satisfying way and practices, he does a Most servicers will give "Guesstimates" of doing business. determine cost serious disservice to the public he for a very reasonable fee of as little as claims to be protecting. $5.00, but certainly cannot then be ex- First, TV, and particularly solid -state pected to give guarantees of any kind. color TV, is the most complex device in We would urge that when shopping, the home. The technology changes so a claim check should be demanded on rapidly that the service people "must run which restrictions, such as estimate only, just to stand still" and so to expect a set be indicated in writing and minimum fee owner to understand it, is idiotic. be indicated. Second, price of sets is predicated We assure you that most servicers, on the fact that most sets in total or at and certainly members of NATESA, are least major sections of it, has been auto- at least as honest as any segment of crownELKHART. INDIANA 46514, U.S.A. matically produced by foreign labor, business, and that means 95 %. They are most of it at $30.00 to $40.00 per week. (continued on page 24) Circle i0 on reader service card 22 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com Introducing the expensive curve tracer that doesn't cost a lot.

The B &K Model 501A. It's a lab- quality instrument that provides fast aralysis o` all semiconductors including J- FET's, MOS- FET's, signal and power bipolar transistors, SCR's, UJT's and diodes. You can test transistors in circuit for GO/ NO GO condition. Badly distorted curves will indicate the stage where a defective transistor or other faulty component exists. The 501A is complete -with scope graticule and FP -3 probe for fast, one -handed in- circuit testing. It generates true current aad voltage steps, with 3% accuracy, for measuring beta at all current levels. And it has a sweep up to 100 volts and 100 milliamperes. With the 501A, curves are displayed on an auxiliary scope screen. And you can hook it up to any scope - 129.95 old or new. All three controls can be set in quick -test positions to test and evaluate 90% of all solid -state devices without manufacturer's data sheets. The 501A won't burn out either the semiconductors or itself. With all these features, you'd think the 501A was an expensive curve tracer. But look at the price. For complete technical data, call your B &K distributor. Or write Dynascan Corporation.

Very good equipment at a very good price.

Product of Dynascan Corporation 1801 West Belle Plaine Avenue, Chicago, Illinois 60613

Circle 11 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 23

www.americanradiohistory.com LETTERS PIK_Malee (continued from page 22) eager to serve the public because most independents are neighbors of their customers so can't hide from them. It is proven fact that the biggest problem is the crt tester haphazard selection of service agency and generally at the critical moment of set failure. Expecting impossible bar- you can afford to take along gains and perhaps gimmicks and gifts leads only to "fast pitch" unqualified oW... $34.95 sharpshooters who, because they continuously lose customers when they finally awaken, must advertise very extensively at cost that obviously is beyond their "hole in the wall" size to justify. Let us also assure you that NATESA is very consumerism aligned, as the dates on the several enclosures will indicate. We worked with law enforcement A quality CRT tester with and protective agencies during the entire individual test for each gun. existence of NATESA in the past quarter Compare guns for emission. century. We can identify provable prob- Test for leakage and shorts. lem areas and problem operators, with- Legible 3 color scale. out maligning the vast numbers of eth- Compact, portable, rugged. ical servicers. Avoid recalls, check the CRT on every call. NATESA take alone the time savers (National Alliance of Television & Elec- WRITE US! PIX -MATE CRYS -MATE GEN -MATE tronic Service Associations) SOUND -MATE TRACE-MATE FRANK J. MOCH The Caddy -Mate Line. Executive Director 5908 S. Troy St. ¢e t 2245 PITKIN AVE., BROOKLYN, N. Y. 11207 Chicago, Ill. 60629

Circle 12 on reader service card For Radio- Electronics editorial view- point on this important matter, see page Why pay an answering 4 in this issue. 4 CHANNEL NOTES service when you can It seems that the discrete /matrix de- bate is doing strange things to its lead- own your own? ers. In each side's enthusiasm to con- vince the reading public that the other Dictaphone has a machine to side is inferior, they let themselves give make sure you never lose an- less and less logical arguments. other cent through a missed Even I could find fallacies in the recent letters in Radio -Electronics between phone call or a garbled mes- Gordon Holt and Peter Scheiber. Writing sage. In fact, we have a whole against discrete 4- channel records, Mr. line of them. Scheiber stated that total separation in They're called Ansafones. You can buy one outright playback is unnatural, forgetting or ig- noring the fact that people who make or possibly lease it for about what you're paying your records don't usually have a certain answering service now. And it works for you 24 hours a sound only in Channel A, but add a little day, 7 days a week. to Channel B so as to give a stereo pan - For a free brochure describing how much an aroma instead of two point sources with Ansafone can help you, mail this coupon now. nothing in the middle between the speakers. What total separation means is the ability to have point sources, which ®Dictaphone musicians and engineers do want occa- sionally. In his reply, Gordon Holt made Box L -2 -34, 120 Old Post Road, Rye, New York 10580 a similar mistake when he said that a Please send me full details of the Ansafone line. frequency range past 10,000 Hz is use- Name less. And Gordon Holt returned to argue that down, saying, "Let's not go 4 -chan- Company Phone nel at the expense of any of the signal Address quality possible in the state -of- the -art City State lip Code recording ". But separation and tight con- IL J trol of directionality are part of that sig- Ansalone and Dictaphone are registered trademarks of Dictaphone Corp. (continued on page 89) Circle 13 on reader service card 24 RADIO-ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com Channel Master's partan Amplifier. It knows how to say 'ENO!"

Anterna amplifiers don': have a good reputation. They Lst seem to sit up there and at-ract all \-\, k nds of trouble. Ch.nnel Maser knows that even ane callbac< is toc many. ?n, frankly, we felt that if the industry :ave yoc a more reliable, troub e -free, higi- performance amplifier, you'd put t;p a Ict mare. That's why we've just engineered a brand r,elA 3-e -- -the Spartan. It doesn't

make problems t solve.; them. N. I,

"No" to signal ove-loading. Tie Spa-tan uses new high- capacity semicondcctcrs :1st can haxil=- up tc 200,000 rricro.ol:s of sigra wttoat cistortian or cros;- modulation. f.o amplifier can feat t.

"No" to lightning damaçe. Lightning sJrges are the #1 cause of amplifier failura. But no you've got the Saarta-. Thanks tc acvancEd new en3rgy- abscrbing dir- .\ cuits and compcnen :a, i: :akes charge after charge-- - aid stil

ta FM interfsre.ce. It's the or ley amplifier with 2 Cb.iilt -in FM t-aps a switc haale filter -hat attenuates sig- `nals 25 dB ac-oss the FM tard, plus a turable t-ap -- -only MHz Aide-- -that jives vu an extra knockout punch e:

' No" lo tropical heal, sit -zero cold and pouring rain. Except cnal stabil ty and reliability in any kind of weathe-. And it maiitains it; flat gain. w :h no oscillation 'or hurt, aven when lira voltage; fluctiate. CHANNEL MASTER SPARTAN SERIES. ANTENNA ÁMPLIFIERS 75 am-3 2.00 oim mcde'ir 'o every necepticn aree. ylr'te ...for guys who for technical Iiteratute. CHANNEL MASTER DIV. afAVNET, INC. can't afford trouble! EIlenvil e N.Y 12422

trrct 14 on reader servece ea l

Nt 'N www.americanradiohistory.com Now...the most enjoyable, do- it- yourself project equipment of your life -a Schober Electronic Organ! report

Aries pocket calculator kit I recommend the following three from B &F items as pre- requisites: I. A good magnifying glass or low -power microscope to inspect the connections. 2. A high -grade fine- tipped tweezers to as- sist in positioning leads, particularly You'll never reap greater reward, those of the LED displays. 3. A spray more fun and proud accomplishment, can of flux remover to clean the more benefit for the whole family, than boards after soldering to allow a care- by assembling your own Schober ful inspection. Electronic Organ. (The problem of possible damage You need no knowledge of electron- to the fine LED leads has been elimi- ics, woodwork or music. Schober's nated. Kits produced now have the 8- complete kits and crystal -clear in- digit readout as one composite unit. - structions show you - whoever you Editor) are, whatever your skill (or lack of it) Assembly proceeds by mounting - how to turn the hundreds of quality the components on the boards, inter- parts into one of the world's most connecting the boards, wiring the bat- beautiful, most musical organs, worth tery supply and the final mechanical case assembly. on main up to twice the cost of the kit. Mounted the board are the eight LED displays, the Five superb models with kit prices LED negative and overange indicators, Circle 26 on reader service card from $500 to around $2,000, each an the 40 -pin IC, the 26 display driver authentic musical instrument actually transistors with their associated resis- superior to most you see in stores, DESIGNED AROUND A 40 -PIN DUAL -IN- tors, and two slide switches. The easy for any musically minded adult line- plastic encapsulated integrated cir- smaller clock /power supply board to learn to play, yet completely satis- cuit, the Aries pocket calculator is a generates the dual phase 25 -kHz clock fying for the accomplished profes- four -function machine that displays and the -4.8- and +2-volt supplies re- sional. And there are accessories you it's answers on an eight -digit LED dis- quired by the chip. The negative sup- can add any time after your organ is play. It uses floating -point arithmetic ply is taken directly off the batteries finished - lifelike big auditorium re- so the decimal point is always posi- while the positive voltage is derived verberation, automatic rhythm, pre- tioned to give a maximum of signifi- by rectifying the clock signal. The sets, chimes, and more. cant figures in the calculated result. A third board, the keyboard, is a clever "K" switch stores an entered constant economical printed- circuit affair that Join the thousands of Schober in a memory register so it can be re- outperformed my expectations. The Organ builder -owners who live in called by the machine to be multiplied keyboard contacts are printed- circuit every state of the Union. Often start- by, divided into, added to, or sub- foil, bridged by a conductive rubber ing without technical or music skills, tracted from in a series of chain calcu- pad. The pad is separated from the they have the time of their lives -first lations. These calculators are great for board by a plastic mask with cutouts assembling, then learning to play the doing all kinds of jobs from balancing corresponding to the various keys. modern King of Instruments through checkbooks to doing homework. The Construction time was about 10 our superlative instructions and play- slide -rule has passed it's heyday and hours followed by an hour of trouble- ing courses. soon will become extinct due to this shooting. At first one digit did not gift the electronics industry. light due to a resistor that was dam- Get the full story FREE by mailing modern of the coupon TODAY for the big The Aries calculator is made up aged during assembly (my fault). After circuit boards; the main replacing the resistor it was possible to Schober color catalog, with all the of three board, the clock /power supply board enter numbers but not perform any of fascinating details! and the keyboard. From the outset it the four functions. You begin to feel is clear that this is not a kit of begin- quite helpless after realizing the defect The .9oño ii Organ Corp., Dept. RE -111 ners and will draw on the skills of the may be out of reach on the chip. The 43 West 61st Street, New York, N.Y. 10023 more experienced. It takes a great feeling was soon dissipated by finding Please send me Schober Organ Catalog. deal of precision and patient care to a cold solder joint at one of the IC Enclosed please find $1.00 for 12-inch L.P. record of Schober Organ music. mount the components onto the fine terminals (my fault again) and with a sprang NAMF board foil patterns. While the instruc- touch of the iron the calculator ADDRESS tions are not highly detailed they are to life. the calculator is CITY STATF 71P adequate for the experienced kit Operation of builder. Before beginning construction (continued on page 88) Circle 15 on reader service card 26 RADIO- ELECTRONICS FEBRUARY 1973

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259/607 558/140 283/672 649/170 COMMUNICA- ELECTRONIC INSTRUMENTS OPERATIONAL TION SYSTEM COMPUTER & MEASURE- AMPLIFIERS ENGINEERING TECHNOLOGY MENTS FOR by Tobey, HANDBOOK 2/e ELECTRONICS Graeme & by Huelsman by N. R. Scott by C. N. Herrick D. H. Hamsher Pub. price, $15.00 Pub. price, $18.00 Pub. price, $13.95 Pub. price, $29.50 Club price, $11.50 Club price, $13.75 Club price, Club price, $22.50 $10.50 209/731 139/296 124/035 109/32X STANDARD AMERICAN HANDBOOK OF ELECTRONICS HANDBOOK FOR ELECTRICIANS PHYSICS, 2/e IN INDUSTRY ELECTRICAL HANDBOOK by Condon and 4/e ENGINEERS, by Croft, Odishaw by Chute & 10 /e Carr & Watt Pub. price, $34.75 Chute by Fink and Pub. price, $22.50 Club price, $14.95 Pub. price, $13.95 Carroll Pub. price, Club price, $18.25 Club price, $10.75 $32.50 Club price, $24.95 MAIL THIS COUPON TODAY Save and money by joining the 7-1'1 time I- Electronics and Control Engineers' Book Club ELECTRONICS AND CONTROL ENGINEERS' BOOK CLUB 582 Princeton Road, Hightstown, N.J. 08520

Please enroll me as a member of the Electronics and Control Engi- HERE is a designed specifically to meet your professional club neers' Book Club and send me the two books indicated below. I am day -to-day engineering needs by providing practical books to receive the bonus for just $1.00, and my first selection at the in your field on a regular basis at below publisher prices. special Club price shown. These books are to be shipped on approval, and I may return them both without cost or further obliga- Hew the Club operates: Basic to the Club's service is its publi- tion. If I decide to keep the books, I agree to purchase as few cation, the Electronics and Control Engineers' Book Club as four books during the next two years at special Club prices (at Bulletin, which brings you news of books in your field. Sent to least 159 below list). members without cost, it announces and describes in detail the Write Code No. of Write Code No, of Club's featured book of the month as well as alternate selections bonus book first selection which are available at special members' prices. here here When you want to examine the Club's feature of the month, you do nothing. The book will be -nailed to you as a regular part of your Club service. If you prefer one of the alternate selections-or if you want no book at all for that month -you notify Name the Club by returning the convenient card enclosed with each Bulletin. Address As of a Club member, you agree only to the purchase four City books over a two -year period. Considering the many books published annually in your field, there will surely be at least four State Zip that you would want to own anyway. By joining the Club, you E 33202 save both money and the trouble of searching for the best books. 1 Circle 16 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 27

www.americanradiohistory.com USE IT ALL AS YOU GET READY FOR A NEW CAREER... $1,500.00 worth of two-way radio electronic communications equipment!

Bell & Howell Schools announces a new learn -at -home program that gives you "hands on" experience with commercial - grade equipment -as you prepare for a business of your own in two -way radio electronic communications servicing. You need "hands on" experience with a real, commercial -band FM transceiver and actual commercial -grade test equipment -to take full advantage of growing opportunities in electronic communications. Two -way radio communications is a healthy growth area in electronics. And it's lucrative. Almost two million commercial two -way radio systems now serve as vital communications links for trucks, planes, boats and taxis. And the FCC requires each system to have its equipment serviced regularly by a licensed technician. That's where you come in. But you need career - oriented training-plus your FCC license. Knowing how to put an amateur radio kit together won't help when you're "on the job" - servicing two -way radio systems for aircraft or advising trucking companies about their land- mobile communications system. For that, you need "hands on" experience with the real thing. This unique is convenient, you can have the equipment new Bell & Howell Schools learn -at -home shipped to your home in return for a $100 program that gives you just that. You can deposit, which is refundable when you work with the equipment by attending one return the equipment. of our special "help sessions" or by Find out more about this exciting dropping by one of the Bell & Howell new Bell & Howell Schools program. There's resident schools. If neither of the,e plans no obligation.

For free facts, mail attached card today! 28 RADIO -ELECTRONICS FEBRUARY 1973

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Bell & Howell Schools has helped thousands of people FCC REGULATIONS GIVE YOU THE OPPOR- prepare for careers -and businesses of their own -in TUNITY TO START YOUR OWN BUSINESS! electronics. You can have absolute confidence in the The Federal Communications Commission re- thorough training you get. quires that all commercial two -way communications Expert instructors at Bell & Howell Schools systems be checked and serviced by a licensed tech- plan each program to answer a single question: "What nician at regular intervals. qualifications will you need to take advantage of actual As a Bell & Howell Schools graduate, you'll career opportunities in electronics ?" They then build have the technical know -how you need. With your FCC each program to give you those exact qualifications. license, you can go out and eventually build your own To get ready for a business of your own in two - business -signing contracts with companies that use way radio, you need: 1) career -oriented training; 2) FCC two -way radio. FCC regulations could mean security License; 3) "hands on" experience with commercial - and regular income for you! grade equipment. Bell & Howell Schools now offers this SCHOOLS new at -home training program that gives you all three. BELL & HOWELL OFFERS YOU (See FCC License Guarantee on attached card.) THESE SPECIAL ADVANTAGES: Help Sessions Scheduled regularly every few JUST LOOK AT ALL THE EQUIPMENT Saturdays at the Bell & Howell Schools and in many YOU'LL WORK WITH other cities throughout the U.S. and Canada. Top in- DURING YOUR TRAINING PROGRAM structors give you personal help and guidance. WITH BELL & HOWELL SCHOOLS! Transfer Privileges After completion, you can Commercial -Band FM Transceiver ... exactly transfer to any of the resident schools for more ad- the kird of two -way radio you'll service throughout vanced study, if you wish. your career Lifetime National Placement Assistance Helps you locate a job where you want to anytime after you complete program. Veterans' Benefits We are approved by the state approval agency for Veterans' Benefits. Student Financial Aid We are an eligible in- = Olo OSCILLATOR _F GENE RAT stitution under the Federally Insured Student Loan * Prog ram. EXCLUSIVE ELECTRO -LAB ® - YOURS TO KEEP! To make sure you get practical experience with instruments used daily by professionals, we've integrated into your program three precision instruments you assemble yourself and keep:

Design Console Use this to rapidly "breadboard" Deviation Meter circuits without soldering, Oscilloscope Offers bright, ... model favored by many sharp images, 3 working technicians to check screen -way for leads, modulation of transmitted signal. jacks plugs. Transistorized Meter Registers Frequency Meter . . . highly sensitive instrument used to current, voltage and resistance. check signal frequency within precise FOR FULL INFORMATION, tolerances established by government MAIL THE ATTACHED CARD standards. TODAY! OR WRITE: Power Output Meter ... meter used almost universally by trained and An Electronics Home Study School licensed technicians to check power output - DVRV InSTITUTE OF TECHrIOIOOV or wattage -of signal. ONE OF THE Alignment Generator BELL 6 HOWELL SCHOOLS 406 R ... a custom -designed unit 4141 Belmont. Chicago, Illinois 60641 you use to generate test signals for transceiver alignment.

FEBRUARY 1973 RADIO -ELECTRONICS 31

www.americanradiohistory.com CCD27 equipment _J u m` U U r e report NEW BIPOLAR MULTIMETER: AUTOMATIC POLARITY INDICATION

Onkyo TX -666 nal level meter damping everything Solid -state stereo receiver seems perfect. Swinging to their final positions quickly and decisively the two meters exhibit no observable Model ES 210K overshoot. The meters use their full

Displays Ohms, Volts or Amps in 5 ranges scale travel usefully. Switching to the Voltage from 100 My to 500 V Resistance AM band turns off the tuning meter from 100 Ohms to 1 Megohm. Current from illumination with the signal strength 100 Micro- Amps to 1 Amp $77.00 meter remaining operative. The knobs Case extra: $12.50 (Optional probe)$ 5.00 and switches are beautifully machined and the red dial pointer is strikingly illuminated by a travelling pilot lamp. A convenient feature is a front panel Circle 17 on reader service card microphone connector and mixing DIGITAL FREQUENCY COUNTER: level control. With a microphone OUTSTANDING IN BOTH ELECTRICAL plugged in, the receiver can be used and mechanical construction and de- as a PA amplifier without struggling sign the Onkyo TX -666 is obviously with rear panel potentiometers, or by the result of attention to detail. Tun- using the mixer control the micro- ing the AM and FM bands with 40- phone output can be mixed and faded and 1.8- microvolt sensitivities respec- with the receiver input signals in all tively, it delivers 60 watts of rms operating ES 220K - Line frequency time base. 1 KHz modes. resolution. 5 digit: $69.50 Case extra: $10 power to each of two 4-ohm speakers. Popping during on /off switching ES 221K - Crystal time base. 100 Hz resolu- If you are impressed with even bigger is prevented by a transient killer cir- tion. 6 digit: $109.50 Case extra: $10.00 numbers this amounts to 200 watts cuit. When switched on, the volume IHF power. With 8 -ohm speakers the increases gradually until reaching the output is reduced somewhat to 50 level determined by the volume con- DIGITAL CLOCK: watts rms per channel. trol. The time constants of the FM FM image rejection is better than muting circuit are ideal so there is no 70 dB, i.f. rejection ratio 100 dB and annoying excessive time lag when tun- signal -to -noise ratio 60 dB as a result ing across the FM band. Electronic

; _' i of a 4 -gang capacitor /FET front -end temperature protection senses high combined with three pairs of ceramic temperatures due to internal or ex- i.f. filters. The remaining pertinent ternal sources. The output power tran- ES 1121(1124K 12 hr. or 24 hr. clock .$46.95 FM specifications are 50 dB minimum sistors are mounted externally on the Case extra: Walnut $12.00 Metal $ 7.50 AM rejection, 0.5 dB capture ratio. rear panel with shock protection 0.5% stereo distortion (0.2% mono), shields, eliminating the main source of and 40 dB separation at 400 Hz. Total heat dissipation from the cabinet inte- Dependable solid state components and circuitry. harmonic and intermodulation dis- rior. Any slight internal heat buildup Easy reading, 7 segment display tubes with clear, tortion are held below 0.2% and 0.3% is taken care of by a neat screened numerals. These operate from bright products 117 respectively. At 1 -watt frequency re- vent slot along the rear top of the VAC, 60 cycles. No moving parts. Quiet, trouble free sponse is 10- 40,000 Hz ± 1 dB with a cabinet for enhanced reliability. Short printed circuit. power bandwidth of 10- 40,000 Hz, circuit protection for the power output Each kit contains complete parts list with all parts, IHF THD 0.2 %. Bass and treble con- transistors gives fool proof main am- schematic illustrations and easy to follow, step by trols have an adequate ±-10 dB range. plifier operation. The rear panel in- step instructions. No special tools required. AM performance is also enhanced cludes the normal phono inputs plus by high- shape- factor ceramic filters. two pairs of auxiliary input jacks. AM image rejection is greater than 40 Three pairs of tape jacks give versatil- dB, i.f. rejection ratio greater than 40 ity in mixing inputs with the super- dB and signal -to -noise ratio 40 dB. vision of the front panel volume and riFibh-- ORDER YOURS TODAY: With the electrical specifications microphone mixing controls. Two sets Use your Mastercharge or Bankamericard listed, here are the features we found of speakers can be hooked up and Money Back Guarantee subjectively interesting, rounding off used in any combination selected by a the receiver's excellence. First the ap- front -panel switch. A large handling

506 Main St.. El Segundo, Ca. 90245 pearance and feel of the front panel chart details the operating functions of (213) 772 6176 controls are solid. From the tuning all front panel controls and jacks. The flywheel inertia to the tuning and sig- (continued on page 80) Circle 17 on reader service card 32 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com We can be instrumental in Radio Shack's exclusive Micronta t test instruments your success. are proof that reliable measurements and rugged "knock- around" dependability can be yours at low cost. Whether you're setting up a service shop or laboratory, or need instruments in your hobby, pay less and get much more with Micronta. Ex- 100k -Ohm Multitester. None finer at this price' Matched clusive at 1600 Radio Shack stores in all 50 states. pair of silicon diodes prevents overload damage. Mir- rored, no- parallax scale; 4" meter; % accuracy. Reads DC volts: 0 -500 mV, 0 -2.5- 10 -50- 250 - 500 -1000 volts at 100,000 ohms /volt. AC volts: 0-2.5-10-50-250-1000 volts at 12,500 ohms /volt. DC current: 0 -10 -250 µA, 0- 2.5 -25 -250 mA, 0 -10 A. Resistance, 0- 2k -20k -200k- 20 meg. Decibels, -20 to + 62 in 5 ranges. Batteries, leads, included. 34.95

20k -Ohm 50k -Ohm Multitester. Versatile "range doubler" circuit. Accurate for both current and voltage ranges - especially recommended 20k -Ohm Multitester. Low -priced VOM with "expensive for low- voltage transistor serv- model" features. Reads DC volts: 0 -5 -25- 125 -500 -1000 icing. 4" meter has color - at 20k ohms /volt. AC volts: 0- 10 -50- 250 -1000 at 10k coded, mirrored scale. Ranges: ohms /volt. DC current: 0 -50 µA, 0 -250 mA. Ohms 0- DC volts: 1.25- 5- 0.125- 25 -125- 6k-60k. Decibels: -20 to + 62. Mirrored scale, single - 500 at 50k ohms /volt; 0.25 -2.5- knob selector With leads, battery. 11.95. 10- 50-250 -1000 at 25k ohms/ volt. AC volts: 1.5-5-25-125- 30k -Ohm Multitester. 31/2" meter is easy to read and has 500 at 10k ohms /volt, 3 -10- single -knob selection. DC volts: 0-0.6-3-15-60- 300 -600- 50 -250 -1000 at 5k ohms /volt. 1200 -3000 at 30k ohms /volt. AC volts: 0-6-30- 120 -600- DC current: 50 MA-5 mA -50 mA- 1200 at 15k ohms /volt. Resistance: X1, X100, X1000. 500 mA -10 A: 25 p.A -2.5 mA- X10k ohms. DC current: 0- .03 -6 -60 -600 mA. Decibels 25 mA -250 mA -5 A. Resistance: to -I- in ranges. Batteries and leads 0 -16k 160k ohms; 1.6 -16 meg. -20 63 5 21 .95 Decibels: -20 to + 62 in 10 ranges. 50" test leads. plugs. batteries. Handle doubles as Dynamic Transistor stand. 27.95 Checker. Shows elec- trode open and short circuits. current gain

. . . to test low, medium, high Variable DC Power Supply. Output -power PNP NPN types. voltages from 0 -24 volts at one and l.I1 8.0 Permits matching of rI})Nlt 4t IAttl. SOW amp. Dual- function panel meter. similar transistors in volts and current. Input: 120 v. operating circuits. GO/ AC at 60 Hz. Output current: 1 amp constant over entire range NO GO test from 5- with 1.5 -amp surge Equipped 50 mA on power types. Front panel quick - with circuit breaker. U L listed check socket; clip leads 29.95 for "in- circuit" test. 12.95 133-1 FREE '73 CATALOG! AT YOUR wasummicau NEARBY STORE OR SEND IN THIS COUPON -,. Syur =y_ 180 pages! Stereo Ri -Fi, CB, Ham, Kits, Radios, trig-2292 Recorders, Tools, More! ftadue Ihaek Name Apt # and ALLIED RADIO STORES Street M A TANDY CORPORATION COMPANY

City State Zip IIII P. Texas L J 0. Box 1052, Fort Worth, 76107 Circle 18 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 33

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At a price most everyone can afford ...... Students, housewives and businessmen alike can now have at their fingertips the newest products of solid -state integrated circuit (IC) technology. FIGURE ... BUDGETS INCOME TAXES PERCENTAGES MONTHLY STATEMENTS GROCERY LISTS CREDIT CARD STATEMENTS

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www.americanradiohistory.com SEE HOW IT WORKS

Digital Clock On A Chip

Twelve- or 24 -hour displays, alarm, snooze -alarm and clock -radio formats are offered in three MOS LSI circuits.

by LARRY SULLIVAN"

A NEW FAMILY OF THREE MOS IC'S FOR played in either 12 -hour or 24 -hour may be set individually with no "car - use in electronic digital clocks makes formats. rys" generated to the more significant possible several different types of The standard United States 60 -Hz digits. Thus, there is no "overrun" "single chip" clocks. These devices power line frequency may be used as when setting the counter to a time have been introduced by Mostek Cor- a reference. If the clock is intended such as 2:59. In a counter in which poration of Carrollton, Texas. for overseas operation where 50 Hz is "carrys" are allowed between digits it All members of this "clock fam- the standard power line frequency, the is very easy to increment the minutes ily" are six -digit clocks that display 50-Hz input frequency reference may "9" by one extra count and change all time in hours, minutes, and seconds. If be selected. The MK 5017 P clock three digits so that the time reads only an hours and minutes clock is senses the power supply voltage and, 3:00. This makes it necessary to reset desired the same IC may be used with if loss of power is detected, displays the hours, tens of minutes, and min- only the two hours and two minutes all "eights ". A backup battery may be utes all over again. digits connected to the display. Out- used as a power supply during tempo- puts from these clocks may be con- rary power loss. An adjustable 50-Hz How it works nected directly to fluorescent -anode or 60-Hz oscillator is included on the Figure 1 is a functional block dia- display tubes. The high- voltage output chip to furnish the frequency refer- gram of the MK 5017 P digital clock transistors allow fluorescent -anode dis- ence during temporary loss of power. circuit. A 1 -Hz reference frequency is play tubes to be driven directly. The clock circuits require only a generated for the time counter by the The MK 5017 P clock circuits are single power- supply voltage, sim- shaper- divider network from either a available now in an alarm clock ver- plifying power supply design. 50-Hz or a 60-Hz input. The 50 /60-Hz sion, the MK 5017 P AA; a clock ra- Time setting is easy, a matter of input frequency may be derived from dio clock, the MK 5017 P AN; and a depressing and holding pushbuttons the ac line or can be provided by an unique combination clock /calendar which allow the internal counters to external crystal- controlled oscillator the MK 5017 P BB. Time may be dis- increment at a 2 -Hz rate. Each of the and frequency divider for portable or 'Mostck Corp., 1215 West Crosby Road, Carrollton. Tex. minutes digits and the hours digits automobile applications. When the ac FEBRUARY 1973 RADIO -ELECTRONICS 35

www.americanradiohistory.com power line is used as a frequency ref- KA KB erence, the user is faced with the 1 problem of temporary power loss. An 50/60 on -chip temporary R -C oscillator may TEMP GATING MK 5017 P be used to provide the frequency ref- 50/60 SHAPER erence through temporary power loss IN DIVIDER periods if a battery is used to provide TIME ALARM chip power through the power tran- 1 Hz COUNTE R COUNTER sient. Time is measured by increment- ALARM AM ing the time counter at a l -Hz rate. COMPARATOR The contents of the time counter are r RADIO INH SLEEP decoded from BCD to seven -segment MULTIPLEXER form and multiplexed out as serial ALARM OREF-of RADIO digits. An external resistor CONTROL and capaci- --II OSC WAKE/ tor may be used to control the fre- 0 SLEEP quency of the scan -rate oscillator and 6 7 SEGMENT TONE thus control the rate at which the dis- DECODE DECODE Vss play digits are scanned. This allows various display types with different -VDD scanning characteristics to be used. Six -digit output strobes identify the digit being multiplexed out of the circuit at a particular time. The digits are scanned sequentially from least significant to most significant. That is, the D1 D2 D3 D4 D5 D6 SA SB SC SD SE SF SG seconds is the tens digit followed by FIG 1 -BLOCK DIAGRAM of the IC for a digital electronic clock. The frequency standard can be of seconds digits which is followed by a 50- or 60 -Hz line. external crystal oscillator or the internal R -C source during power outages. the minutes digit. An alarm counter may he set externally in the same manner as the generates approximately (- 35Vdc). These display tubes have a com- time counter. While in the alarm set Reference diode D3 reduces the power mon cathode and heaters. The 6.3 Vac mode, the contents of the alarm supply output voltage to ( -I5V) for winding of transformer TI is reduced counter are displayed. In the run the IC's Vi,t, supply voltage. The op- to approximately 4.2 Vac by. resistor mode when the alarm comparator de- tional backup batteries shown may be R4 since the individual filament volt- tects coincidence between the time used to prevent loss of time during age is about 0.7 volt. This series fila- counter and the alarm counter the temporary power transients. Diode D2 ment "string" is biased at about alarm control circuit generates an remains OFF isolating the batteries (- 25Vac) by transistor QI. alarm tone. (The new Heathkit GC- from the power supply in normal op- Display brightness can be varied 1005 digital clock kit is built around a eration. If ac power is removed, D2 is by adjusting variable resistor R5 version of the Mostek IC. The de- biased on by the batteries and pro- which sets the base voltage of transis- scription of the alarm clock that fol- vides the integrated circuit with Vin tor Q I. QI acts as an emitter follower lows is the Heath clock. - Editor) supply voltage to prevent loss of time. keeping a constant cathode bias on While the ac power is OFF the voltage the display tubes. MK 5017 P AA on the 50/60 IN pin remains at a There are two function input pins. I he alarm clock version of this steady logical one. The chip detects KA and KB. Both KA and KB pins are chip, the MK 5017 P AA. features a this condition and continues to mea- sampled during each digit strobe. The 24 -hour alarm. An alarm tone at a sure time using its own 50/60 Hz in- intersection of the six -digit output frequency of approximately 700 Hz is ternal oscillators as a time base. strobe lines and the KA and KB lines generated on the chip by an internal The frequency of this oscillator forms a matrix that is 6 X 2. That is. oscillator. This alarm tone. suitably may be set at either 50 Hz or 60 Hz there are 12 potential locations where buffered, may be coupled into an in- by adjusting R I. a spst switch may be located. These expensive miniature speaker. When ac power is present. the 60- switches may be used to define 12 sep- An AM /PM indicator is also pro- Hz sinusoidal waveform from trans- arate functions or modes of operation vided to allow setting the alarm on a former TI is half-wave rectified by for the circuit. For example. at D6 24 -hour basis. The AM /PM output. diode DI and reduced from a ( -35) time the KA line is sampled to deter- designated AM in Fig. 2. is pulled volt peak to a voltage one or two volts mine if the time set switch is closed. If high to Vss by the transistor to in- more negative than Vn,t, by the resis- the time set switch is closed, the KA dicate AM. The AM output appears as tive divider composed of R2 and R3. line will he pulled high to Vss by the an open circuit for PM. Capacitor C2 serves as a noise -spike DO output driver transistor. Isolation If seconds are not being displayed suppressor and prevents false counts diodes D5 through D16 prevent the the user may wish to use the optional from noise spikes induced on the ac digit outputs from being tied together closures. I -Hz output. available upon request. line by equipment using SCR switch- in case of multiple switch to blink the AM /PM indicator. This ing or universal motors. For example, if the time set switch at provides a visual indication that the Fluorescent -anode display tubes the intersection of D6 and KA and the clock is running. Figure 2 shows a are shown in this example. As shown. hours switch at the intersection of D5 typical circuit for a digital alarm clock fluorescent -anode tubes may be driven and KA were both closed, the D5 and using the MK 5017 P AA or MK 5017 directly by the clock circuit. The dis- D6 digit strobe outputs would be tied P AN and seven- segment fluorescent - play tube anodes are connected together if diodes D6 and D7 were anode display tubes. The power sup- directly to the clock segment outputs. omitted. At D5 time D6 is reverse - ply consisting of transformer T I. recti- The cathodes are driven by the indi- biased so the D6 line is not pulled fier diode D4, and filter capacitor C3 vidual digit outputs. high by the D5 output. Similarly, at 36 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com FOR 60 Hz) (SELECT 1 Hz SQUARE TEMP 1 Hz 50/60 WAVE OUT VDD R1 C7 AM R19 0.1T REF 150K (SELECT FOR R2 R3 1 C2 100K Hz) MOS R21 39K 47K 50/60 IN /LS1 CLOCK R20 T.01 MK 5017 P AA /AN RADIO SLEEP -- 100K 150K D VSS RADIO TO AM /PM WAKE /SLEEP -- C4 INDICATOR VDD ; `if 51pF - KB TONE KA 1NH D6 D5 D4 D3 D2 D1 SA SB SC SD SE SF SG

I- -- T S 24 SL4 SL

I C3 D6 i7 D10 EJ 1 50 SL2 SL1 A :r I R25 I L TO RADIO

RADIO SEL. SW. D13 D14 D15 D16 D5 J 1 - ON L_ 2 - OFF MEE 3 - RADIO WAKE NOTE 1 4 - ALARM

D314 D4 -35V NOTES 2OV 1N4001N 1. CIRCUITRY WITHIN DOTTED LINES T1J USED ONLY WITH 5017 AN. ,025.2 VAC IME 2. ALL COMPONENT VALUES AND VOLTAGES SHOWN ARE NOMINAL. C3 3. SELECT R2 & R3 FOR PEAK VOLT- t00 µF 11 SEC ó AGE 1 OR 2 VOLTS GREATER 50V + THAN VDD 4 INDICATOR TUBES ARE 1SE DG )10 SEC 10 A OR EQUIVALENT. 5. ALL DIODES ARE 1N914 UNLESS 6.3 VAC rANNONN OTHERWISE SPECIFIED. R4 6. ALL RESISTORS ARE 1/4 W., MIN 820 )1 UNLESS OTHERWISE SPECIFIED. READOUT MORMON HEATERS INPUTS MIN !MORMON )10 AS ALARM SET DISPLAY 11-01 BRIGHTNESS j USED TO SET HRS, 10M, 1M. 11 HR (OPTIONAL) SN - SNOOZE 7 MIN IIMMOHNN EA - ENABLE ALARM 24 - TWENTY -FOUR HOUR DISPLAY

10 HRS 50 - CONVERTS COUNT TO 50 Hz INPUT SL SLEEP moranenen SL 2N3906 R18 SL 2)- SLEEP CODE SL 4 150K 150K 68K1 68K TS - TIME SET R5 el 10K THE SEVEN SYMBOLS (+( IN EACH HORIZONTAL LINE REPRESENT ELEMENTS IN 7- SEGMENT READ- OUT. A SOLID BAR (1) REPRESENTS ONE OF THE SEGMENTS AS, DASHED BAR (-r) IS THE CATHODE

FIG. 2- COMPLETE DIAGRAM OF A DIGITAL ELECTRONIC CLOCK. Fluorescent -anode display tubes can be driven directly by the IC.

D6 time D7 is reverse - biased so the closed in the rIME SEr mode. In this SET mode of operation the contents of D5 line is not pulled high by the D6 mode of operation the contents of the the alarm counter are displayed. The output transistor. Since the KA and KB time counter are displayed. Counting time counter continues running while inputs are time multiplexed, it is pos- is stopped in the TIME SET mode and the alarm is being set. sible to connect 12 switches to only the seconds and "tens -of- seconds" dig- Closing the switch located at the two input pins keeping the circuit in a its are both held at zero. When the intersection of the D5 and KA lines 24-pin package. time set switch is released, the clock causes the hours digit to advance at As shown in the INPUTS table on begins running. the rate of two digits per second, (a 2- Fig. 2, the switch located at the inter- The switch located at the inter- Hz rate). Closing the switch located at section of the D6 and KA line defines section of D6 and KB is used to define the D5 and KB intersection causes the the TIME SET mode. The switch is the ALARM SET mode. In the ALARM minutes digit to advance at a 2 -Hz FEBRUARY 1973 RADIO -ELECTRONICS 37

www.americanradiohistory.com rate. If both the hours and the min- D2 and KB lines (SL2). and at the in- utes switches are closed simultaneously tersection of the D2 and KA lines the "tens -of- minutes" digit advances (SL2). are used to select the desired service twice each second. sleep time. There are eight possible Enabling the alarm is accom- combinations that may be achieved notes plished by closing the switch located with these three switches, so a total of at the intersection of the D4 and KB eight different sleep times may be se- lines. When coincidence is detected lected. The switches are arranged in a G -E C2 /L2 COLOR CHASSIS between the time counter and the binary code with the switch designated TINT CONTROL INEFFECTIVE alarm counter, the alarm tone is gen- as SL1 being the least significant bit. Color rendition may or may not be close to normal. Check or replace the 3.58 -MHz crystal. A universal re- SLEEP SWITCH TABLE placement may not work. Original parts numbers are EP41XI and Radio Sleep Time Switch Combinations EU41X3 for 3 -lead and 2 -lead crystals, SL4 SL2 SL1 respectively. -G -E Service Hints 10 Min open open open 20 Min open open closed TV REPAIR SAFETY CHECKS 30 Min open closed open Here are several safety pre- 40 Min open closed closed cautions that should be observed when 50 Min closed open open servicing television receivers: 60 Min closed open closed 1. Always use the original manu- 90 Min closed closed open facturers' replacement component or a 120 Min closed closed closed replacement that is of equal quality. 2. When service is required, observe the original lead- dress. Use extra erated for one hour if the enable The switch designated as SL4 is the care to assure correct lead dress in the alarm switch is closed. most significant bit. The times that area of high- voltage circuitry. When the alarm "goes off' the may be selected, along with the switch 3. Where a short circuit has oc- snooze switch located at the inter- closures required to program these curred, replace those components that section of the D4 and KA lines may be times, are presented in table. show evidence of overheating. momentarily depressed to inhibit the After selecting the desired radio 4. When replacing the back cover alarm. After seven minutes the alarm sleep time from the table, close the of the set, check the position of the ac will go off again. This cycle may he sleep switch to start the timing inter- interlock to confirm a proper con- repeated indefinitely. val. It is not necessary to install three nection. CAUTION. Before returning Twelve or twenty -four hour time switches and remember the binary any equipment to a customer, make displays may be selected at any time code for sleep times. Instead, an eight - sure that no shock hazard exists by without disturbing the time counter. position three -pole rotary switch may performing the following checks: Closing the switch located at the inter- be used to easily and rapidly select a) Plug the ac line cord directly section of the D3 and KA line results sleep times. into a 120 -volt outlet (do not use an in a twenty -four hour display. In addition to the radio sleep fea- isolation transformer for this check). For operation from a 50-Hz refer- ture the MK 5017 AA also has a radio b) Using two clip leads of suf- ence frequency, the switch located at WAKE /SLEEP output. The radio ficient length, place a 1500 -ohm, 10- the intersection of the D3 and KB lines WAKE /SLEEP output is operative during watt resistor in series with an exposed may be closed. When this switch is RADIO WAKE and RADIO SLEEP opera- metal cabinet part and a good earth open, the clock assumes a 60-Hz refer- tion. For RADIO WAKE operation the ground such as a water pipe. ence frequency. radio WAKE /SLEEP output is on when c) Use an ac voltmeter with a the alarm counter and the time sensitivity of 1000-ohms- per -volt or MK 5017 P AN counter become equal. The radio more to measure the voltage across Clock radio clocks may be built WAKE /SLEEP output remains active for the resistor. A reading of 3.0 volts or using the MK 5017 P AN. This circuit one hour during radio wake operation. more indicates a shock hazard that includes all of the features normally A display inhibit pin is included must be corrected. found on a clock radio clock. Both the on the clock -radio clock circuit. All of d) Move the resistor connection alarm clock - MK 5017 P AA, and the the segment- and digit-output transis- to each exposed metal part (antennas, clock -radio clock - MK 5917 P AN are tors are disabled (turned off) when the handle bracket, metal cabinet, screw shown in Fig. 2. The circuitry shown inhibit pin is connected to Vss. This heads, control shafts, metallized plastic by dashed lines applies to the clock - feature makes it possible to build a overlays, etc.) and measure the poten- radio clock. The remaining circuitry is multifunction clock using only one tial across the resistor at each new common to both. display, without any external multi- connection. In addition to all of the features plexing circuits. R -E e) Reverse the plug in the ac out- found on the alarm clock circuit the let and repeat the measurements in COLOR TV RECORD GROWTH clock -radio circuit also has a radio steps c and d. As of October 1, 1972, the sleep output that may be used to keep Correct any shock hazards before total number of households in a radio or other appliance on for se- returning the instrument to the cus- the U.S. that have color TV in- lected periods of time up to a maxi- tomer. -RCA Television Service Bulle- creased to 37,300,000, according mum of two hours. tin to the latest quarterly estimate by Radio sleep operation is selected the National Broadcasting Corn - NEXT MONTH by closing switch SL at the inter- pany. This represents an in- March is a special stereo issue. section of the DI and KA lines in the crease of 3.8 million in color -TV You won't want to miss any of input matrix. The switches located at households since January 1, the exciting articles. It goes on the of the Dl and KB intersection 1972. sale February 20th. lines (SL1) at the intersection of the 38 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com (INFRARED:

ONE OF THE MOST EXCITING PARTS OF THE ELECTRO- magnetic spectrum is the portion between visible light and and its radio waves, the invisible infrared Sir William Hershell discovered the existence of invisible "light" just beyond the visible spectrum in 1800 when he noticed that a thermome- many 1 ter placed just adjacent to the red part of a spectrum produced by a prism indicated a temperature rise. Since the newly discovered radiation was just beyond the red, Her- applications shel] called it infra -(meaning below) red. Since 1800, hundreds of applications have been found for infrared. But technological achievements in lasers and infrared detectors have greatly increased the variety of applications in recent years. For example, sensitive infrared detectors are being used in non -destructive testing of many Before infrared can be forms of electronic components and circuits -including used for many complex integrated circuits. The military is using infrared in a great variety of applications ranging from invisible applications, we must beam communication systems to thermal mapping cameras either detect or measure it. that photograph enemy territory under cover of total dark- is ness. A military application that has made news in recent Here how these are months is the so- called "smart bomb." Guided to its target accomplished by the invisible infrared beam from a powerful laser, these new guided bombs give Air Force pilots uncanny accuracy in combat situations. by FORREST MIMS There are many other applications for infrared which are entirely new, and we'll discuss some of them shortly. But first let's see how infrared is generated and how it can be detected. Infrared sources Amazing as it seems, all matter with a temperature greater than absolute zero (a chilly -273° C) emits some degree of infrared radiation. This radiation may have a wavelength ranging from the near IR at about 0.8 microns to the far IR in excess of 30 microns. The wavelength is related to temperature, and cold objects emit at much longer wavelengths than warm objects. For example, human skin at its temperature of about 98.6° F emits IR radiation at a range of wavelengths centered around 9.3 microns. Objects with a higher temperature emit at shorter wavelengths which may even include the visible part of the electromagnetic spectrum -hence the expressions red hot and white hot. Half the radiation from the sun is in the IR and more than 80% of the light from an incandescent lamp falls outside the visible spectrum and in the infrared. Many lasers, FEBRUARY 1973 RADIO -ELECTRONICS 39

www.americanradiohistory.com including most of the semiconductor versions, emit very companies the IR projected onto a detector surface. narrow wavelength lines of infrared. For example, the gal- Quantum detectors exploit electron -hole movement within lium arsenide laser system described in the June 1972 issue a semiconductor. of Radio -Electronics emits at a peak wavelength of about The simplest thermal detector is the one used by Her- 0.91 microns, while certain lead -salt semiconductor lasers shell in 1800, the common thermometer. IR striking the emit at wavelengths extending out to 30 microns. thermometer heats the liquid within. The liquid, typically Other sources of IR include flames, arcs, and what is colored alcohol or mercury, expands and rises through a called a blackbody. The blackbody emitter is used to cali- glass capillary marked with a calibrated scale. More re- brate IR detectors and operates on the principle that a per- cently, a "solid state" thermometer using a coiled bimetal fect absorber of [R is also a perfect emitter. A typical strip is commonly used. In operation, heat causes one side blackbody may have the appearance of a cone (Fig. 1). IR of the bimetal strip to expand more than the other, making the coil wind or unwind. A pointer connected to the center of the coil indicates the temperature. Other thermal detectors also use mechanical techniques. The Golay Cell, for example, consists of a xenon - filled chamber that expands when IR is directed into it. The expansion of the cell, hence the amount of IR, is indicated by a tiny mirror connected to a bellows. A beam of light directed against the mirror and reflected onto a calibrated scale indicates the quantity of IR. This kind of detector is called a thermopneumatic cell. FIG. 1-BLACK- Electronics has greatly improved the simplicity and BODY as an IR de- reliability of thermal detectors. The thermocouple has al- tector a may be ready been described. Consisting of a junction of two dis- INCOMING RAY OF I R IS ALMOST block with cone - similar wires, thermocouples COMPLETELY ABSORBED BY THE shaped aperture a are among the simplest of IR WALLS OF THE CONE AS IT BOUNCES near -perfect IR ab- detectors. BACK AND FORTH. sorber. A more sensitive detector is the bolometer, a soot blackened piece of platinum foil. A wire attached to either entering the cone is reflected from wall to wall with a large amount being absorbed by the wall of the cone. By the time the radiation reaches the apex of the cone, most of it has been absorbed. The blackbody emitter can also be used as an IR detector. Such a device is called a calorimeter and it is frequently used to measure laser energy. In operation, the outside surface of the cone is connected to an array of tiny thermocouples that measure the temperature increase of the cone as IR is projected into it. By comparing the temperature rise with a calibration curve, energy can be measured accurately.

LEAD SULFIDE DETECTORS have PbS wafers between thin quartz lay- ers for protection and transmission of IR It is designed to sense.

end of the foil is connected to a meter that measures the resistance change in the foil as it is heated by infrared. Be- cause of the soot, the foil absorbs nearly all the infrared striking it, thus making measurements easier to perform when very small quantities of energy are involved. PYROE`LECTRIC DETECTORS THERMISTOR BOLOMETERZ A more sophisticated electronic thermal detector is the thermistor. Consisting of a tiny semiconductor chip, the thermistor is essentially a heat -controlled resistor. Its small size gives it fairly rapid response time. Thermistors are inexpensive and are frequently used for temperature stabili- zation of electronic circuits. TYPICAL IR DETECTOR TYPES. Most of the photon detectors shown Recently, a new type of electronic thermal detector has are In Dewar vacuum bottles for low-temperature operation. become popular in IR sensing applications. Called the pyroelectric detector, its operation depends upon the absorp- Most practical calorimeters use two cones. Each one is tion of heat by a thin wafer of a ferroelectric crystal such connected to a separate thermocouple array. One cone reas triglycine sulfate (TGS). The crystal is fabricated in such ceives the IR being measured, and the other serves as a a manner that it resembles a capacitor. Heat alters the reference to counteract the effects of ambient temperature value of the capacitor, and the resulting change can be changes. monitored by suitable circuitry. Since the detector has a high output impedance, sometimes they are made with a Detectors of infrared self -contained FET stage to reduce impedance to a more The cone calorimeter is actually one of two classes of acceptable level. IR detectors. The two classes are thermal and quantum de- The thermal detectors we have been discussing are too tectors, and the calorimeter falls in the thermal class. Ther- slow or not sensitive enough for many applications. The mal detectors depend on the temperature increase that ac- development of improved quantum detectors has helped al- 40 RADIO- ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com leviate this problem. Thermal detectors tend to have slow PEM detectors operate on the principle that a mag- rise and fall times since the detector itself must become netic field will separate charge carriers in certain semicon- heated by the IR. Since the heating requires a finite time, ductors. Indium antimonide, the material used for both the detector has a relatively slow response time. Quantum photoconductive and photovoltaic detectors, and mercury detectors do not depend on heating of the detector for telluride (5% ZnTe, 5% CdTe) are both used in PEM de- proper operation. They use the movement of holes and tectors. electrons in a semiconductor material exposed to infrared. There are three major classes of quantum detectors: Infrared optics photoconductive, photovoltaic, and photoelectromagnetic The question of infrared transmitting materials is an (PEM). The first two operate just like their visible light important one. Detectors must be protected by windows, counterparts, photoresistors and photodiodes. and the windows must be rigid and transparent to the IR One of the most common infrared sensitive photoresis- being detected. Furthermore, since many IR detectors are tors is the lead sulfide cell. Closely related to the cadmium operated at very low temperatures for improved performance, the window material must be able to withstand thermal stress. In visible light applications there are a great variety of materials that are transparent. But materials that are transparent to the human eye and visible light may be corn - pletely opaque at IR wavelengths. Conversely, objects that are opaque at visible wavelengths may be transparent to infrared. For example, standard window glass transmits little or no IR beyond about 4 microns, while germanium, which is completely opaque at visible wavelengths, transmits about 50% of the IR between 2 and 15 microns. Other ' 1I1FRARtO DETECTOR materials that transmit IR include such exotic substances as potassium bromide, cesium iodide, cadmium sulfide, and sodium fluoride. Even common table salt, sodium chloride, is transparent to IR out to 20 microns. Typical applications for infrared optics include missile seeker heads, Dewar windows, and laser systems. Optics for lasers that emit in the IR beyond several microns pose a difficult problem for research scientists. For the carbon dioxide gas laser, for example, emission is at 10.6 microns. Sodium chloride is one of the few materials that makes a suitable window at this wavelength but it has a tendency to absorb moisture and become clouded. Therefore, salt windows on some IR lasers are removed when not in use and QUANTUM INFRARED DETECTOR. The window visible In the bottom stored in humidity free containers. of the Dewar assembly is transparent to infrared wavelengths. Putting infrared to Work sulfide cell used to detect visible light, the lead sulfide Since the infrared emitted by an object can be directly (PbS) device employs bulk material without a pn junction. A typical cell consists of a quartz substrate containing two evaporated electrodes separated by a thin space. A strip of PbS is deposited across the space separating the electrodes in the form of a semiconducting bridge, and tiny wires are connected to the electrodes. The cell is completed by bond- ing a thin quartz cover onto the substrate to form a protective window. Quartz is frequently used because of its infrared transmission properties. There is a great variety of other photoconductive infrared detectors. While PbS is used for wavelengths peak- ing near 2.5 -3.0 microns, indium antimonide (InSb) is used for the 6 -7 micron range. Doped germanium detectors are used for much higher wavelengths. For example, mercury- doped germanium (Ge:Hg) is used for 10 microns and zinc -doped germanium (Ge:Zn) for 20 to 38 microns. Ge:Hg is frequently used in military systems designed to detect human beings since its peak sensitivity nearly matches the peak IR emission of the target. Photovoltaic IR detectors include silicon (Si), germanium (Ge), indium antimonide (InSb), and mercury cadmium telluride (HgCdTe). While photoconductive cells alter their internal resistance when illuminated by infrared, photovoltaic detectors generate a voltage. Silicon and germanium detectors have a peak response in the near IR at around 0.85 to 1.4 microns respectively. They are particularly useful for detecting near IR beams from lasers and light- emitting diodes. They have very fast response times and good sensitivity. The other detectors listed above are Photos courtesy Barnes Engineering sensitive to longer wavelength IR and are used in a variety THE PHOTON DETECTOR, shown in closeup photo at upper left, is in of detection applications. a Dewar vacuum Jar for operation at temperature of liquid nitrogen.

FEBRUARY 1973 RADIO -ELECTRONICS 41

www.americanradiohistory.com related to the object's temperature, devices that can sense to permit vision in total darkness. Semiconductor lasers, infrared have many practical applications. For example, light emitting diodes, or filtered incandescent or xenon simple IR detectors are used to monitor equipment that be- lamps provide the IR. The military and police find night comes overheated and triggers an alarm when the tempera- viewing systems particularly important, but biologists and ture exceeds a certain level. The same technique is used in astronomers also use image -conversion devices. IR fire alarms. Image- converter tubes are impractical at wavelengths In more sophisticated systems, IR detectors are used to beyond about 1.1 microns. For longer wavelengths, IR detect animals and people. In one setup two slits in front quantum detectors are employed in a mechanical scanning of a detector cause the device to give an output signal only system. A system of mirrors scans the desired field of view when the source of infrared has moved. In this way the de- and the output of the detector is fed into a CRT. The re- tector ignores temperature changes and only gives an out- sult is an image of the IR emitted by an object even put when a valid signal is received. though the object may be in total darkness. By using detec- Systems that use IR to form visual images have many tors sensitive to 10 microns, we get particularly startling re- valuable applications. The simplest technique for rendering sults. For example, the system can "see" a human body a visible 1R image is to use infrared - sensitive photographic and convert it into an image on a CRT screen even though film. The Eastman Kodak Company makes several kinds of the subject is in darkness. black -and -white and color [R sensitive film. The films are Infrared scanning cameras are finding a host of appli- sensitive to visible light and infrared out to about 0.9 mi- cations in research and practical engineering. The cameras crons and produce striking effects when used to photograph are expensive, but the applications frequently justify the scenery and landscapes. The film is also useful for photo- price. Military uses are obvious, and each of the services is graphing the beam from near -IR lasers, detecting forgeries, investigating thermal cameras for camouflage and person- inspecting art objects, and conducting aerial geological and nel detection. The Army's Night Vision Laboratory at Fort agricultural surveys. Medical applications include locating Belvoir, Virginia, is particularly interested and active in this certain skin diseases, photography of the retina, and study- area of work. ing human behavior without the knowledge of the subject. Industrial applications include detection of hot equip- For applications beyond 0.9 microns, image -converter ment from a distance, non -destructive testing, analysis of tubes are frequently used. These tubes contain an IR sensi- welds, and studies of a variety of manufacturing and fabri- tive photocathode coated on thin glass window at the front cation techniques. Medical applications include the detec- of the tube and given a high potential with respect to one tion of some kinds of cancer, circulation impairments, and or more electrodes at the rear of the tube. In operation, vascular diseases. In earth science studies, IR scanning visible or near IR striking the photocathode triggers the cameras are used to detect pollution in bodies of water, emission of electrons which travel toward a phosphor study the effect of irrigation systems, find diseased crops, coated viewing screen. The phosphor screen then glows in and even prospect for mineral formations. a pattern identical to that of the IR projected upon the A modification of the scanning camera transfers the photocathode. image to photographic film instead of a CRT. These sys- Image converters are sometimes used with IR sources tems preserve a record in hard copy of the scene detected and are commonly used in aircraft. Both the military and the Forest Service employ many of these systems, the former for reconnaissance under cover of darkness and the latter for finding forest fires. What's ahead The past few years have produced a genuine revolu- tion in infrared generation and detection techniques, and if present developments are any indication, we can expect to see even more startling developments in the next few years. For example, the newly developed charge-coupled self- scanned silicon arrays, another Bell Telephone Laboratory invention (see New & Timely, Radio-Electronics, Novem- ber, 1972, page 6; and June 1971 page 6.) will permit the fabrication of solid state television systems. The silicon used in present arrays responds to the near infrared, and if InSb and similar materials can be adapted to the technology, far infrared self scanned arrays may only be several years away. Other developments equally as impressive INFRARED CAMERA, manufactured in Sweden by A. B. Bofors, has can also be expected, making infrared a field to be closely numerous applications In medicine, science and Industry. watched. R -E

OLYMPIC TD20 TAPE DECK 5. Replace the chassis and secure. No further recur- A problem of drive belts slipping off the motor pulley rence of this problem should be anticipated.- Olympic Ser- may be due to a coating of oil on the pulley and the inner vice Bulletin surface of the drive belt. This is caused by oil spraying from the upper motor bearing as operating temperature SQUEAL- INSUFFICIENT WIDTH rises. Therefore, a tape deck may not show signs of this Squeal from the high -voltage cage along with possible condition until after the first hour of operation. reduced width may be caused by chips from the high -volt- Handle complaints of displaced belts by: 1. Com- age transformer core. These chips will vibrate in their lodg- pletely remove the belt from the mechanism. ing place -usually in the air -gap between the halves. If the 2. Operate the motor continuously (without belt) for core is cracked (usually at the right -angle corners) chips four hours. will lodge in the crack. Removing the chips will reduce the 3. Wipe motor pulley and capstan pulley clean of oil. squeal, but if the core is cracked, it should be replaced. If 4. Invert belt and reinstall so the dry side becomes the the portions of the cracked core are separated, insufficient inner running surface. width may occur.- General Electric Service Hints 42 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com cover story /cover story/cover story/cover story/cover story/co

LIKE THE PROVERBIAL MODEL T FORD harmonic content of the sharp rise cause of the many different pulses the old single- trace, recurrent -type wavefronts, without any overshoot. found in the TV video signal. (free- running) service scope may soon The faster the scope's rise -time the become obsolete on the service bench. better. And of course, most all trig- Triggered and automatic With the many sophisticated gered scopes offer the choice ac or dc sweep modes solid -state electronic devices now on vertical amplifier modes at the flip of To make sure that every one un- the market that require circuit diag- a switch. Both vertical amplifiers must derstands what a triggered scope ac- nosis, the dual -trace triggered scope is be balanced and have identical fre- tually is let's take a brief look at its well worth its cost. You can now quency response and amplification. operation. The sweep circuits of a trig- choose from several models of these The primary advantage of a triggered scope are inoperative and the glowing one -eyed dual- sweepers. Some gered scope compared to a service crt blanked (no trace visible) until the technicians tell us they cannot afford scope is that its sweep can be started proper trigger "on" pulse is applied to to be without one. Many models are precisely at the same point on each the sweep circuit. When the correct now all solid- state, easy to operate trace. This lets you make very accu- pulse is received, a one -shot type of and can cut your troubleshooting time rate comparisons between two signals circuit goes into action, unblanks the considerably. The dual -trace scope is or two pulses of the same frequency. crt, produces one sweep across the

DUAL -TRACE TRIGGERED -SWEEP SCOPES

Once a lab instrument, the triggered -sweep dual -trace scope is now a must on many service benches. by ROBERT L. GOODMAN

just like having two scopes in one This is needed to check for correct screen and resets to the "off' state. unit, but at a very small additional timing of the color burst, color killer Sweep does not recur until another cost. and gated agc circuit operation. pulse of correct amplitude and po- The scope's sweep is actually larity is applied to the sweep circuit. Dual -trace scope features turned on or "triggered" by the signal Most of these scopes also have a free - I he triggered -sweep oscilloscope, pulses that are fed into the vertical running sweep mode. A sample pulse be it single or dual -trace, should have amplifier. These pulses are "picked - is picked off the input signal that is these features. The horizontal sweep off' at the vertical amplifier of the fed into the vertical preamplifier stage speed should go to 500 kHz or higher scope and fed into the trigger sweep to provide the sweep trigger pulse. (also referred to as the time -base gen- circuits. This is the reason for the This is why the triggered instrument erator frequency range). This means rock -solid scope traces. For TV trou- produces a stable pattern and solid -as- you have fewer waveforms to look at bleshooting the scope should have the a -rock lock and is easier to use than on the crt when checking high -fre- special horizontal and vertical (Tvv the old -time recurrent -sweep service quency signals like the 3.58 -MHz and TvFI) sweep or time -base ranges. scope. color CW oscillator. To have solid lock on the vertical and The automatic triggered feature is The frequency response of the horizontal TV sync pulses the scope no doubt the most useful mode. This vertical amplifiers should be flat to at should have a special TV -type sync mode of operation presets the trigger least 10 MHz. This is needed to see separator or filter circuit. Without this (sync) level so that adjustment of the the color burst at 3.58 MHz and the filter the scope may not lock -on be- sync level control is not needed. The FEBRUARY 1973 RADIO -ELECTRONICS 43

www.americanradiohistory.com automatic triggering provides a trace across the crt at all times, with or without an input signal present. The sweep runs at a slow irregular rate until a trigger pulse is sensed. When a signal is applied, the automatic trigger circuit goes into action and gives you a sharp, clean trace with triggered stability. All that has to be set is the input sensitivity and the correct sweep speed needed for signal display. Thus, fast waveform checks can be made without having to jazz around with all FIG. 1 -IN A DUAL ALTERNATE DISPLAY FIG. 3- KEYING PULSE and video signals must of the scope controls. only one trace may be visible. have this relationship for good agc action.

Alternate and chopped dual traces Most dual -trace triggered scopes offer dual -alternate and dual- chopped sweep modes. The dual -trace alternate sweep is the most useful for TV trouble-shooting. The trace actually displays each scope channel alter- nately. The channel A trace is displayed on one sweep while the next sweep cycle displays the channel B input. Then the process starts over again with channel A. Both traces are con- FIG. 2-CHOPPED MODE Is best for dual dis- FIG. 4 -COLOR BURST at burst amplifier plate trolled independently except for the play of signals below 60 Hz. compared to keying pulse on amplifier grid. triggering. It is controlled by whatever trigger source is selected. One signal is time between traces and helps to elim- color receiver has poor or no color, then displayed with reference to the inate the flicker. The chopping fre- use the dual -trace scope to check the other channel. When channel A is se- quency is high enough to provide an color burst gate circuit. The scope lected as the trigger source, the chan- unbroken display of both signals even photo in Fig. 4 shows the correct tim- nel B signal is displayed in "real though they are displayed in segments. ing of the keying pulse at the grid of time" as compared to channel A. This The chopped mode can be used to the keyer tube and the 3.58 -MHz results because the sweep, regardless look at TV vertical sweep signals. burst on the plate. of input signals being displayed, is For a receiver that displays incor- controlled by the signal present at the Color TV troubleshooting tips rect color, connect the two scope channel A input. This is very useful The color TV receiver has some probes (one for another scope chan- when you wish to compare the phase waveforms that must occur simulta- nel) to the demodulator grids for a between two signals. Not only are neously. Some examples are the burst phase check of the 3.58 -MHz CW de- both signals seen, but with a dual - amplifiers, color killer and keyed or modulating signals. Compare both sig- trace triggered -sweep scope, you can gated agc circuits. With a dual -trace nals for proper phase angle. If the see them displayed on a "real time" scope two pulses can be monitored on phase angle is not correct look for a basis for accurate comparison of tim- the screen to see if they are arriving at fault in the phase -shift network. ing or phase relationship. This, of the same time. This permits you to The dual -trace scope is also course, is not possible with a single - determine width and timing relation handy for checking the delay line in trace triggered scope. to each other and note how this would the video amplifier section. Tune the The chopped mode is primarily affect circuit operation. set to a TV station and use the hori- used for dual -trace display of low -fre- Many concurrent waveforms are zontal sync pulse as a reference. Con- quency signals below 60 Hz. With now found in modern electronic de- nect amplifier A of the scope to the such a slow sweep in the dual alter- vices. One example of exact timing is delay line input and amplifier B to the nate mode, the trace blinks because in the keyed agc system. The agc output terminal. Switch the scope to the crt's phosphor persistence is not keyer must have both the video signal alternating sweep and the horizontal long enough to last until the next at its grid and the flyback pulse at its time base to 2.5 -µs per division. Also trace arrives. As an example, in Fig. 1, plate, with correct timing, in order to use the expanded sweep, if the scope the scope is set for dual alternate develop agc voltage. The correct rela- has this feature. Now, compare the sweep to look at two 20-Hz square - tionship and timing of these signals is leading edges of the two sync pedes- wave signals. Note that the bottom shown in Fig. 3. tals as shown in Fig. 5 and note, as in trace cannot be seen. However, with The color section of the TV re- this case, the correct 0.7 -µs time delay. the scope set in the dual -sweep ceiver must have accurate pulse timing This is a fast way to check the delay chopped mode both square wave sig- for proper operation. The color burst line action. nals are seen in Fig. 2. The dual - amplifier stage separates the trans- chopped mode provides a steady dis- mitted burst signal from the composite Stereo troubleshooting tips play by switching between channels A video signal and must be keyed on Now let's use the dual -trace scope and B at a 100 -kHz rate. This means precisely at the right time by the fly- for some stereo channel -comparison channel A signal is displayed on the back pulse. The 3.58 -MHz burst is testing techniques. The basic concept positive swing of the 100 -kHz chop- present on the back porch of the hori- of this method is to compare the oper- ping square -wave, and the channel B zontal blanking pedestal and has a ative channel with the inoperative signal is displayed on the negative 0.2 -µs duration. Thus burst and keying channel. With this system a very rapid swing. This reduces the amount of pulse timing is very critical. If the procedure can be developed to pin 44 RADIO- ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com point defective components for all comparison testing techniques. The very weak the preceding stage must be types of stereo amplifier and multiplex tests are begun by feeding the square - checked. Each time you move up one FM systems. wave test signal into the left and right stage the amplifications should in- The triggered dual -trace os- amplifier input channel jacks. The left crease in level, but don't be fooled by cilloscope along with a square -wave and right channels are actually tied to- gainless stages such as cathode or audio generator are the instruments gether. Tune the square -wave gener- emitter followers as they add no volt- used to make these following checks. ator to 1 kHz initially. Now, the age gain to the signal. Of course, these techniques can be probes from channels A and B of the used for solid -state or tube -type stereo dual -trace scope are connected to the Rapid isolation of intermittents equipment. same, but opposite test points of the Here is a way to use the dual - To use this technique one of the stereo amplifier's left and right chan- trace scope to isolate intermittent cir- amplifier channels must be operating nels. The two sets of square -waves on cuit faults. The volume of a stereo correctly so you can compare wave- the scope are then compared for any amplifier may go up and down occa- forms with the defective one. Both discrepancy. sionally or an intermittent distortion waveforms may then be superimposed condition could be the complaint. for an exact analysis and even minor Tracking down the trouble Some of these amplifiers may operate distortions can easily be detected. One channel of this stereo ampli- for days before acting up. This When both channels are working cor- fier (Fig. 7) had developed a very low method can help solve those inter- rectly you see identical twin images of volume level. The square -wave gener- mittent conditions. Start by feeding a the two square -wave traces on the ator and scope were connected for a square -wave signal into the suspected scope screen. few checks. When the probe from channel and connect both scope Before these scope checks are channel A of the scope was touched to probes to different sections of the am- made some routine tests of the stereo the collector of Q402 and probe from plifier as shown in Fig. 9. Now, when amplifier will have to be performed. channel B was placed at the base of the trouble develops just look at the These initial checks include current Q403 the scope pattern in Fig. 8 ap- scope pattern and if no change takes drain, faulty or overheating transistors, peared. Note the loss of signal gain in place move the probes to other sec- burnt resistors, loose solder con- the lower scope trace. A defective cou- tions. nections and cracked or broken circuit pling capacitor (C415) caused this loss This technique was used on the boards. Frequently, after these checks of gain. This same technique is also stereo amplifier shown in Fig. 7. The and necessary repairs are made, one useful to compare stereo multiplex sig- dual -trace scope was connected and of the amplifier channels will operate nals. To quickly isolate the fault just the fault was isolated to an inter- correctly. put the scope probes at the various mittently open coupling capacitor. Shown in Fig. 6 is a block dia- stages and evaluate the scope traces. This was C4I2 at the base of Q402. gram illustrating a dual -trace scope Start at the amplifier input and work This was found when one probe from and square -wave generator connected up stage -by -stage to the speaker. the scope was connected to the high to a stereo amplifier to perform these When the signal is lost or becomes side of the bass control and the other

SQUARE -WAVE OR PULSE RIGHT CHANNEL A PROBE GENERATOR CHANNE L

INPUT

FIG. 5 (above) -DELAY LINE CHECK. Bottom LEFT trace of horizontal sync pulse is delayed 0.7 CHANNEL Ins, proving that line is OK. FIG. 7 (below) - FIG. 6 -BLOCK DIAGRAM showing how a dual -trace scope can be used to track down inter - ONE CHANNEL of stereo amplifier tested. mittents and other defects in a stereo amplifier. Dual traces make it easy to compare channels.

0402 0403 PRE AMPLIFIER PRE -DRIVER DRIVER 12V LOUDNESS TREBLE C415 43K 3.9K CONTROL .0068 CONTROL 2/15V +5% + +15.0V !f +84V C412 2.2 MEG 68npF FROM +6.6V 10K RIGHT .0068 INPUT +0.56V 150K 50K +6.1V 5/12V 18K +1 OV +0.32V 180K 50K BASS 2.2K 5 CONTROL 470 22 pF 220 TAPE 15K 220K 22K OUTPUT 015 10K TpF 33K 18K 200

+-1_<35V 250K RIGHT TO 330 pF BALANCE LEFT CONTROL SPEAKER CHANNEL CABLE TO LEFT CHANNEL

FEBRUARY 1973 RADIO -ELECTRONICS 45

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In the Master TV /Radio Servicing Program, City State Zip you -guild and keep the all solic -state if interested in Classroom Training O bla_1 and white TV set, the color TV set, the Check here osciFoscope and multimeter sh3wn above. Veterans Check here

FEBRUARY 1973 RADIO-ELECTRONICS 49

www.americanradiohistory.com sponse of a stereo amplifier can read- BATTERY SAVER ily be checked with this system. Battery- powered instruments are fine -except that if you are like us, Stage gain comparison you often forget to turn off the ones measurements. without the ever friendly and reas- Modern dual -trace triggered suring pilot light. This results in run- scopes have identical vertical ampli- down batteries it seems, just when you fiers and their gain is calibrated in need them most. Things sometimes get volts per centimeter (volts /CM). This so bad that I forget to unplug the sol- makes an ideal instrument to check dering irons at the end of the day. If one stereo channel against the other it was not for plated tips, I would one to compare the signal gain of have had to spend a small fortune re- FIG. 8 -LOW AMPLITUDE of one trace shows a various stages. This can be used for placing burned -up tips. loss of signal somewhere between the two checking the gain per stage throughout In desperation I made several probes. small battery- powered neon relaxation (RC) oscillators (Fig. I) that I turn on

SQUARE -WAVE 10 MEG GENERATOR CHANNEL A PROBE

INPUT

CHANNEL B PROBE DEFECTIVE STEREO CHANNEL LEFT OR RIGHT

FIG. 9- SIGNAL TRACING in single channel of an amplifier Is easy with a dual -trace scope. One scope channel views input signal; the other checks the signal stage -by- stage. FIG. 1

the amplifier and for overall perfor- whenever I turn on a battery- powered mance of the left and right channels. instrument. These are located strate- This makes it very easy to compare gically throughout the shop so that the the left amplifier with its twin on the blinking neon lamp is a reminder that right. a battery- powered instrument is on. The dual -trace scope can also be The operating life should equal the used to simultaneously monitor the in- shelf life of the batteries. Mine have put and output signal of any type of been operating for over two years. electronic processing stage, whether it The soldering iron problem I be oscillating, amplifying, switching or solved in an equally simple manner. A isolation, solid -state or tube type. Be- neon lamp assembly wired in the sol- cause of the ac or dc vertical amplifier dering iron stand (Fig. 2) lights to FIG. 10- SQUAREWAVE TEST SIGNAL at In- mode of operation of these scopes the TO SOLDERING put; the straight line shows a loss of signal. peak -to -peak ac signal level along IRONS with the dc voltage level can all be probe at the base of Q402. When the seen with just one glance at the scope defect occurred we got the scope trace screen. shown in Fig. 10. It doesn't take long Thus, you can double your plea- to isolate an intermittent problem this sure in many instances by actually cut- way. ting your troubleshooting time almost But if the intermittent is within a in half. multi -stage feedback amplifier, this The dual -trace triggered os- technique will not work unless the cilloscope is invaluable for rapid trou- NEON LAMP ASSEMBLY feedback loop is opened first. bleshooting of today's sophisticated (BUILT -IN RESISTOR) In the example of Fig. 7, the de- solid -state space age electronic devices. fective capacitor (C4I2) was at the in- R -E put to a three -stage feedback loop. This isolation technique would not have worked if C4I5 or C420 was intermittent. 117V With this technique you can l quickly isolate the problem right down to the defective component. As a final check of the amplifier or if you sus- FIG. 2 pect inadequate frequency response, use the square -wave generator and show that the stand and soldering tune it throughout the audio range of iron(s) are plugged in. the amplifier. Make these checks at These may seem like a lot of about 1 -kHz intervals and view both work to solve simple problems, but channels on the dual -trace scope at "The repairman wants to know i( they save in frustration and replace- the same time. The frequency re- two -channel or four- channel!" ment costs!- William D. Kranengel, Jr. 50 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com GRINCHWAL READOUT MODULE

Complete your mainframe. Build this 4 -digit readout assembly using LED's and get ready for the plug -ins that follow

by DON LANCASTER

HERE'S A FRESH, HIGH PERFORMANCE diagram of the counting module. Prac- nary transistors, even high gain ones, approach to digital counting and dis- tically everything is crammed inside may NOT be substituted. play- combine a bright red light emit- the single Mostek MK5005 integrated Capacitor Cl sets the scanning ting diode (LED) display with a single circuit. Monsanto MAN -4 light -emit- rate for the multiplexing while C2 new high performance, MOS In- ting -diode (LED) displays are used. gives a speed -up to the decimal point tegrated Circuit, and you come up These are a fifth of an inch high and input that eliminates ghost decimal with an easy -to -build four decade readable beyond eight feet. Brightness points. Feedback from the decimal 0 -9999 digital counter and display that is good enough for almost any reason- point driver to the chip controls the neatly fits a single 21/2" x 51/4" plug -in able room lighting, and you can even leading zero blanking. PC card. Total supply current, in- hold back on brightness to extend the Brightness is controlled by resis- cluding the readouts, is a mere 6 volts battery life and still come up with a tors R2 through R9. The values shown at 100 mA, easily provided by ordi- highly viewable display. are the minimum recommended values nary flashlight cells. Now you can go that give maximum display brightness. truly portable with your digital in- Construction If desired, the resistors may be raised struments, free of any line cords, Figure 2 shows the actual circuit. in value to give a not as bright display bulky storage batteries, or high -voltage Darlington driver transistors are that has longer battery life. display supplies. While the maximum needed to get the IC outputs up to a A printed- circuit board is a must counting frequency of this display is suitable level for display drive. These for this project. You can get one com- 250 kHz, you can easily count to 100 are pnp or npn transistor pairs as mercially or else you can use Figs. 3, MHz and beyond by suitable scaling. shown and have gains in the ten thou- 4 and 5 to make your own.

Figure 1 shows a simplified block sands. They cost 45 to 60C each. Ordi- While the MOS integrated circuit

FIG. 1- DISPLAY MODULE BLOCK DIAGRAM. Single low -power Integrated circuit does the job. It replaces more than a dozen conventional ICs.

UNITS TENS HUNDREDS THOUSANDS DISPLAY DISPLAY DISPLAY DISPLAY

O BLANKING

SCANNING O DECODER O DRIVER OSCILLATOR LAMP TEST DECIMAL POINT SCANNING IS MUCH FASTER OUTPUT O THAN EYE CAN FOLLOW LEADING ZERO J ELIMINATOR & DECIMAL POINT Ó O O INPUT

UNITS TENS HUNDREDS THOUSANDS STORAGE STORAGE STORAGE UPDATE STORAGE

UN TS TENS HUNDREDS THOUSANDS OVERFLOW a COUNTER COUNTER COUNTER LATCH COUNT COUNTER OVERFLOW

O RESET

FEBRUARY 1973 RADIO -ELECTRONICS 51

www.americanradiohistory.com RO1 - R04 MAN 4 TOP OF NUMERAL BOTTOM VIEW

R0202 R03 R12 RO 100S Q1 UNITS rI' R14 -A/VS. Q1 04 R11 - R14 ANODE MPSAI3 DRIVERS . .12 10K TYP. R7' R5' -O DP1K 4752 4752 DP100 +6V -O 08 NC O O DP10

UPDATE O DP1 1000 +6V +6V RESET O NC 100 R8" COUNT O +6V 10 4752 C3 O- 0.1 O NC EXTEND Q7 1C1 OVERFLOW O NC MK5005 O DP IN TOP VIEW +6V GND 1 O GND SEGMENT BLANK Q5- 12 DRIVERS MPSA65 R1 R15 SCAN 2.2K 10K

LAMP TEST +6V :R10 1C2 410K

SCAN CAPACITOR Cl DP FEEDBACK % Q13 0.1 'MINIMUM VALUE. MAY BE RAISED TO INCREASE MPSAI3 +6V7 BATTERY LIFE & DECREASE BRIGHTNESS FIG. 2- (above) COMPLETE schematic of the readout circuit. o R14-- 01 o FIG. 3- (bottom right) FOIL PATTERN of the DIGITAL GRINCHWAL COUNTER & DISPLAY readout Is 51/4 x board 2' Inches. o DP1K FIG. 4- (right) PARTS PLACEMENT for the _...I 3 02 in- -1 o readout board. R12-- (- 1 i- -1 r- I- .-0R3 DP100 03Q R4 o DP10 ( ROI ( I R02 R03 R04 NC o o 04 -R11- DPI I I is now pretty well protected against UPDATE o o NC static and overvoltage, REVERSED RESET o L J L J L J L J +6V o 0 SUPPLY POLARITY WILL IMME- COUNT R2 NC EXTEND 0 ICI DIATELY AND PERMANENTLY C1 NC o 1012 DAMAGE THE DEVICE. IN ALL OVERFLOW MK5005 U{(I UUU U DP IN o OF YOUR CIRCUITS AND ALL GROUND GND o D ° BLANK D,¡`flDDDDD, OF YOUR CHECKOUT WORK, A 05 07 08 010 011 06 R15 09 R10,f, SERIES DIODE OR OTHER "IDIOT SCAN o o PROOFING" MUST BE PLACED I O LAMP TEST a 013 BETWEEN THE MODULE AND THE SUPPLY. Before starting assembly.. note three very important details: (I) don't unwrap the MOS integrated circuit or remove its protective foam until immediately before you solder it in place: (2) note that the readouts mount fbi! side, opposite the rest of the components: and (3) note that the pins on the plug in connectors stick out from the component side, opposite to the foil side that supports the readouts. A deep red optical filter is absolutely essential for proper display contrast. A piece of "s" red plexiglas 52 RADIO-ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com 030 - DRILL (4) LO PT Oti.a.LJ PARTS LIST (Fig. 2) R1 -2200 ohms, '4 watt, 10% 'o=t'-L (20) D21t-t_ R2, R3, R4, R5, R6, R7, R8, R9 -47 ohms, '/. IG - 6 watt. 10% (see text) (12EMAININ( --o EJ) R10, R11, R12, R13, R14, R15- 10,000 ohms. Y. watt, 10% C1, C3- 0,1 -pF disc ceramic I C2 -1000 pF disc ceramic IC1- MK5005P (Mostek) DO NOT SUB- STITUTE J1, J2 -10 -pin male connector (modified Molex 09 -57 -1105) al, 02, 03, 04, Q13 -MPS A13, npn Darling- ton transistor pair (Motorola) DO NOT SUB- STITUTE 2Z Q5, 06, Q7, 08, 09. Q10, 011, 012 -MPS A65, pnp Darlington pair (Motorola) DO NOT SUBSTITUTE R01, Rot, R03, R04 -MAN -4 LED seven -segment readout (Monsanto) MISC: PC board; 5 jumpers; red filter, 11/4 x 21/4 x 'b" #2423 Plexiglas; sockets for J1 and J2, Molex 09 -52 -3103 NOTE: The following are available from Southwest Technical Products, 219 W Rhap- Lt)IiE J,MPERS onnPo..Er.Y sody, San Antonio, Tex. 78216. MAKE FROM RÉSt1oR EAOS Etched & drilled circuit board- DGR -b, $3.85. IC1 -$20 Kit of all parts -DR-c, $34.50

+6 VOLTS PARTS LIST (Fig. 7) R1, (R2') ohms, '/2 watt. 10% 10K -100 C1 µF, 10V, electrolytic COUNTER MODULE -5000 C2, C3 -500 HF, 25V, electrolytic FRONT 0.47 µF DECIMAL POINT C4° -500 HF, 6V, electrolytic VIEW -. (SETS COUNT D1, D2, D3, D3- 1N5061 silicon diode SELECT RATE) O ODP1K NCO 1N914 D5-1N4742, 12V, 1W, Zener diode D6 ° -1 N4736, 6.8V, 1W, Zener diode O I O DP100 UPDATE O- 1 F1 -0.1 A fuse and fuseholder O 0 DP10 RESET O Q1 *- 2N5191 npn silicon transistor O DP1 COUNT O T1- transformer: primary, 117Vac; secondary. IN4001 lo NC EXTEND O "FOLLOW "HOLD" 12.6V, 100mA with et O Of 0 +6 OVERFLOW O O *Regulator: A Fairchild No. 7806 regulator NC O NC GND O- may be substituted for these parts. 6 VOLT 1 220µF o NC BLANK MISC: PC board, line cord, strain relief termi- SUPPLY 6V 2.2 nals, mounting hardware O DP I N SCAN O 0.1 MEG O T O GND LAMP TEST NOTE: The following Items are available from Southwest Technical Products, 219 W. Rhap- OBSERVE sody, San Antonio, Tex. 78216 Etched & drilled board -B, POLARITY' p01- circuit -DRP $2.50 O O parts $8.75 LAMP TEST RESET Kit of all -DRP,

O Q1 #2423 is ideal for this and may either O GOLD SIDE be bolted directly to the module (us- 7806 DOWN TOP ing long enough spacers to clear the VIEW readouts) or the filter may form a I I front window for a display or in- E B C A 7806 REGULATOR zI I óI MAY BE SUBSTITUTED strument package. FOR THESE PARTS T1 Using it F1 300MA 01A The module may be powered BLK D1 Cl Q1 from a six volt unregulated supply, 117V 5000 2N5I91 four D cells, or a regulated supply. 60-- 1N5061 10V SMALL One suitable line operated supply is BLK D2 HEATSINK shown in figure seven. This particular D6 supply also puts out -12 volts which is (6.8V1 C4 +6V handy for a companion time base IN4736 500 chip, the MK5009, or for other ex- 6V o ternal circuitry. The display goes out before the r+ C2 R1 counter quits. If ultra -long battery life 500/25V 10052 1 -12V OPTIONAL o is essential, you can reduce the bright- -12V SUPPLY C3 D5 ness by increasing the values of R2 FOR OUTSIDE D4 D3 CIRCUITS IN5061 thru R9 to perhaps to 220 ohms, or to

z2tzv I = IN4742 whatever tradeoff between battery life L J and brightness you want. Or, you can go to alkaline D cells or NiCad's. Or- FIG. 5 -(top) DRILL AND JUMPER GUIDE for the readout circuit board. FIG. 6.- (middle) TEST dinary heavy -duty D cells should last CIRCUIT for breadboarding initial checkout. FIG. 7- (bottom) RECOMMENDED POWER SUPPLY you around 40 hours of intermittent fpr ac operation. For portable use simply use four "C" or "D" cells connected in series. operation. R -E FEBRUAR Y 1973 RADIO -ELECTRONICS 53

www.americanradiohistory.com Flexible. versatile, medium duty, low professional quality keyboards are yours for a quarter a key and customized to post your particular needs

keyboards by DON LANCASTER

WHAT COULD YOU DO WITH A LOW - keyboard versions here. The first is a ating force of 3 to 5 ounces. This is cost keyboard? Besides such tradi- 12-key version for calculators, elec- low enough for the keyboard to talk tional uses as adding machines, ham tronic security locks, Touch Tone sys- to virtually any integrated circuit logic radio -teletype and automatic Morse - tems, or data entry. The second is a system without any buffering or isola- code senders, electronic security locks, full 55 -key teletypewriter -style key- tion. It is also smooth enough to give etc., there's a whole new world of board for computer terminals, commu- "soft start" click -free contacts for elec- wonderful new integrated circuits that nication systems, and deaf listening tronic music operations. While the key open the doors to a wide range of aides. A later article will show you a travel is typically 3/16 -inch, you can new projects. Projects that right now low -cost ASCII encoder that converts easily make it anything you want. aren't practical because commercial the contacts of the big keyboard into There's also a definite increase in me- custom keyboards are too expensive an eight -bit parallel IC logic -com- chanical force well after contact is and too hard to get in small quan- patible standard computer code. Along made, so for most applications, you tities. with this, we'll show you a 100 word - can easily tell when contact has been For instance, you can now get per- minute adaptor. Together the key- made, particularly if you have a dis- MOS calculator chips for less than board, encoder and adaptor can give play alongside you can watch. Op- $16. This and a low -cost keyboard and you a complete sending end of a tele- tional "clickers" of one sort or another a display gives you an add- subtract- type style computer terminal for a can be added if they are absolutely multiply -store calculator for way un- fraction of the usual rental or pur- needed. The assembly is reasonably der the going price. Or, one keyboard, chase price. thin, projecting only 13/16 -inch be- an encoder, and a coupler buys you hind the keybottom. I used standard, one half of a computer terminal you How it works commercial two -shot molded keytops. can call up your timesharing service Figure 1 is a cross section of one These are white on grey and are avail- with -at a tiny fraction of commercial keyswitch. We use a 1/4 -inch thick soft able in a wide variety of characters, unit or rental costs. carbon -urethane sponge contact. The numerals, and punctuation. Blank and Low -cost keyboards also open the contact is made by pressing the foam oversize keys are also available. The doors to programmable calculators, sports car rally computers, computer KEY FOP data entry, and such new blue -sky projects as cable television "answer back" systems, electronic notebook RETURN and message centers, communications SPRING aides for the deaf, sophisticated electronic security devices, elaborate elec- TOP /- tronic games, programming for music PANEL DAMPING composers and synthesizers, teaching PAD 1/4" machines, tape or cassette file search flar, systems, credit card verifiers, inquiry systems, recipe, bibliography or literature data banks, "anti -drunk driver" gadgetry, and many, many others. But, commercial custom key- ir,laf boards are expensive. Normally, you pay 80¢ to $2 per key for a 12- or 16- PLATED PC CONTACT key assembly, and as much as $6 per CARBON - PANEL KEYSTEM URETHANE key for a fully- encoded teletypewriter CONTACT style keyboard. Surplus is a help, but SPONGE made from a KEYBOARD ready for mount- only if you can use the keyboard as is. FIG. 1- INDIVIDUAL KEYS are CALCULATOR components. ing. Note the printed -circuit connector. And the "Let's use pushbuttons!" few easily obtained route usually ends up with hard -to- against a pair of plated contacts on a two -shot molding process means the read characters, harder operation, and printed circuit board. This system gen- character goes all the way through the impossible wiring. erates very little switch noise and keytop. It cannot wear off, come loose, Yet, for a few nickles worth of bounce, as the sponge particles pro- or change color. Conventional springs materials, you can build yourself a gressively make and bring about a and an optional damping pad return a custom medium -duty keyboard set up smooth change from an open circuit pressed key to its home position. Op- for your particular task. to a low resistance. ON resistance is tional Belleville washers or a snap -ac- We'll show you how to build two usually under 500 ohms for an oper- tion strip of polypropelene can be 54 RADIO- ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com added for snap- action or tactile feed- in Fig. 2 -b. The disc must be perfectly their IC's in for shipment. If you're back, but this only adds to the cost square with respect to the keystem. using the free material, check several and complexity for most users. Immediately before soldering, care- companies, for some of the material is The parts are detailed in Fig. 2. fully clean both pieces with a type- more suitable than others. A good ma- A keystem assembly is made up of a writer style ink eraser to guarantee the terial will be soft yet still give 500 piece of 3/64 x 3/16 x l' /4 -inch sol- solder will smoothly and strongly ad- ohms or less resistance, and it won't derable soft steel and a 17/32 -inch here. Liquid rosin solder flux helps crumble or tear. Be absolutely sure disc of light gauge solderable steel. Be greatly, but isn't essential. As with any that the keypad sponge is centered sure the part of the keystem that goes electronic assembly, don't use acid and square with respect to the key - into the keytop is cut to fit tightly. core solder or flux. stem. You should lightly centerpunch 4 or 5 After soldering, remove all excess Two 1/16-inch panels support the "pockmarks" on each side of the very solder with a Vs-inch diameter round switches. These are spaced 3/s inch top of the keystem, or else glomp on file, and smooth and polish all edges. apart using 6 -32 threaded spacers. a small self-grip locking plier- wrench Also remove any remaining flux. Since the keystem is a conductor, both heavy enough to cut in teeth marks. Press a slit 0.4 x 0.4 x 0.25 inch panels must be insulators except where This helps lock the keytop firmly in piece of carbon urethane onto the contact is to be made. Use an ordi- place during final assembly. keystem. You might like to optionally nary 1/16-inch single -sided printed The disc is soldered to the key - glue it to the keydisc. If you do, use circuit board for the bottom panel, stem exactly as shown in Fig. 2 -a, an absolute minimum of adhesive and contact side up; and an etched -off keeping it positioned exactly 13/16- be sure not to fill any of the sponge piece of PC material or other 1/16- inch from the keytop end and keeping voids. The glue really isn't necessary. inch fiber glass for the top panel. the solder only on the keypad end. A The carbon -urethane foam may be Be sure to follow these guidelines small wood or other non -heat con- obtained from the source listed, or in your PC layout. Keys are normally ducting jig is absolutely essential dur- you can use the foam many MOS in- 1/4-inch apart. The contact areas should ing soldering. A simple one is shown tegrated- circuit manufacturers wrap be 0.4" square total, with enough clearance between both contact halves 189 MIN 13/16" THICK HARDWOOD and the keystem. Conductors between "EMBOSS " WITH .193 MAX BLOCK DRILLED 3,16" the CENTERPUNCH OR CLIP OR contact pads should be small VISE GRIP JAWS CLAMP enough and centered enough so that a slightly misaligned keypad can't cause an unwanted short. With a calculator 13/16" or telephone style keyboard, the rows 020" of keys are 1 -1/4" usually centered on top of L each other. With a typewriter style SOLD ON THIS keyboard, the rows are usually offset

+I SIDE ONLY: to allow normal typing. Normally REMOVE BOTTOM BLOCK you'll also want to provide a PC edge - .047 MIN I- EXCESS WITH card connector on your layout for sys- .051 MAX I f 1/8" ROUND (b) BREAK tem interconnection. While you can go CORNERS FILE USE A JIG LIKE THIS FOR SOLDERING to multiple contacts and self-encoding FIG. 2 -HOW KEY IS MADE. Construction of the keystem Is simple and well within the keys, this does add complexity and abilities of most technicians and experimenters. Care and precision insure a reliable key- 1/4" lal board. I.D. KEYSTEM IS MADE BY SOLDERING A SLIT WITH X ACTO STEEL DISC & STRIP TOGETHER KNIFE & SLIDE INTO PLACE T SLIT WITH X ACTO KNIFE EXACTLY 9 SLIDE INTO PLACE ON & 7/8" TURNS .016 J_ A VERY KEYSYSTEM. -OR-- MUSIC WIRE F-.4H SMALL AMOUNT OF GLUE MAY BE OPTIONALLY ADDED. _L_ T I I t= .25" 1/16" (c) (e) CONTACT PAD IS MADE FROM 1/4" (d) SPRING LOOKS LIKE THIS. START WITH CARBON URETHANE FOAM. SLIT DAMPING PAD IS MADE FROM 1/16" AN EXTENSION SPRING, STRETCH SHOULD BE ACCURATELY CENTERED. THICK INNERTUBE STYLE RUBBER. IT & CUT EVERY NINTH LOOP FEBRUARY 1973 RADIO -ELECTRONICS 55

www.americanradiohistory.com might be difficult to do on a single - clean everything during final assembly. sided board. A rough edge or a thumbprint can +5V Holes for the keystems are mod- cause long term wear or contact resis- erately critical, and the bottom and tance problems. Also check to be sure top panels must be match -drilled or each keypad seats flat on its contacts. match -punched in their exact final po- Assembly starts with the bottom panel sition. Start with the bottom panel, and threaded bushings, followed by foil side up and either punch or drill the keystems, the damping pads, and and file rectangular holes for each the top panel. These are all bolted to- keystem. The holes should be large gether and operation is carefully enough to allow the keystem to slide checked. Once smooth operation is freely by, but not so large that the keystem can rotate excessively. Edges f h.156 TYP. 10K should be beveled slightly. After the TYP PC panel is punched, drill the mounting holes and firmly bolt the top and bottom panels together backwards, so the drilled panel is on top and the un- KP drilled one is on the bottom. File 1d/ notch across both panels to indicate their alignment for final assembly. The top panel can then be match -drilled or match -punched to the bottom. This 3/4" TYP 3-3/4" way, all the keystems are perfectly vertical and freely slide after final assembly. If you try to drill top and bottom separately, some the keystems 0.4" of TYP are sure to bind or be crooked. f O f r. The return springs may be chopped out of larger hardware store 2-3/4" springs, or wound with music wire. The inside diameter should be some- FIG. 3 -PC PATTERN for a keyboard. Use ex- treme care when drilling holes for keystems. what over 0.2 inch. The uncompressed length should be around 3/4 inch and the spring should squash beyond 1/4 inch without bottoming. Wire diame- KP 2 is ter 0.16 inch. The restoring force (b) should be around 3 ounces when com- -5V pressed 1/4 inch and 6 ounces when compressed '/z inch. The ends should be wound or ground so they do not cut into the top panel or keytop when in use. The bare copper contacts on the PC board must be protected against long term corrosion that will raise the contact resistance. Gold, nickel, or tin plating is ideal, but you can use ordi- DISASSEMBLED KEYBOARD showing key- nary silver ink "PC stems and the carbon- urethane sponge con- Repair" paint pro- tacts. vided you thin it properly and bake it on. A better product is Sel -Rex SIL- PAINT 2065 -01. It is thinned with denatured alcohol and brushed on. 0 I/1 I 81 You then bake it in a kitchen oven at 6 200 degrees for two hours. The resul- u 14I I 5 I 3 tant carbon on silver contact is almost as good as gold plating and is far eas- u o o Il 121 131 +DC OR (flfl ier to do with limited equipment. o oI t I I Commercial keyboard kits are already 0 a 1 'I plated. LOAD During final assembly, you might TOUCH -TONER CALCULATOR like to add an optional damping disc FIG. 4- TWELVE -BUTTON KEYBOARDS in the calculator formats. SCR that goes below the top panel and standard Touch -Tone and above the steel disc on the keystem. obtained, the springs are added, fol- -J- This pad can be about 1/16 inch thick +5 V o--a which are and can be made of innertube rubber lowed by the keytops + _ pressed on till they firmly seat. A tiny or most anything similar. The pad 2.2K 2.2 quiets the keyboard operation, and amount of silicone grease may be op- Keep shortens the keystroke. Changing the tionally added to the keystems. "KP" = KEY PRESSED pad thickness lets you control the A KEY IS PRESSED keystroke. FIG. 5 (right) -WHEN (d) Be sure to polish, smooth and collector current flows in the transistor. 56 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com all grease well away from the contact output does, be sure you use only the conjunction with the American Stan- areas. leading edge of your "key pressed" dard Code for Information Inter- command. Should a second key be de- change (ASCII). The key arrangement 12 -key keyboard pressed before you let go of the first of Fig. 7 can be used, or you can set The printed circuit pattern for the one, it will not be entered, giving you up your own. A cross -section of the I2- button keyboard is shown in Fig. 3 a form of "2- key -rollover" protection. keyboard is in Fig. 8. and in the photo below it. One common If desired, an external speaker, sole- The big keyboard is slightly more connection is provided, but you can noid, or Sonalert clicker may be complex than the little one. Mechani- easily break this if you are using your added to the basic keyboard to pro- cally, extra spacers are needed to pro- contacts in a matrix form. You can ar- vide additional operator feedback. vide a "honeycomb" type of support range your keys any way you like, but A standard 18- connector PC edge all the way across the keyboard. Two

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dIMM

Q'N\ ií' di' Li fi Yi fi fì fi i3 f3'Ei'f3`'k3 k1"`- 6 -3/4'

I g j ti t [is o o

14" i FIG. 6 (above) -PRINTED -CIRCUIT PATTERN for full 55 -key typewriter lands. Add a jumper vertically from each key -contact land to the land or teletype keyboard. Each key has two contact pads connected to PC that is directly above it in one of the 22 horizontal rows.

FIG. 7 (left)- TELETYPE KEYBOARD for AS- CII computer code. Make yours anyway you wish. Fig. 8 (below)- CROSS -SECTION OF A COMPUTER KEYBOARD. Extra spacers pro- s ai vide C1' 9 DEL stiffening. 1 2 4 5 6 7 o n can dcl d62 dc3 dc4 nak syn etb can em die gs us

ALT o W1 E R T Y U o P [LE CR /TOPPANEL dcl etb eng dc2 dc4 em nak ht si dle null

3í8" I I BOARD CTRL A s F G H J K L n n I I JUMPER soh dc3 eot ack bell bs 1f vt ff esc sub rs MATRIX

G SHIFT Z X C V B N M C2' SHIFT ANGLE BRACKET sub can etx syn stx so Cr is rs us em 1/4" X 1/4" X 14" ALUMINUM

SPACE BAR THREADED SPACER$USE INSULATED SPACERS OR SHRINK TUBING ON INTERNAL SPACERS two "standard" formats are the "calcu- card socket fits the keyboard. One aluminum angles run the length of the lator" and "Touch- Toneltl " arrange- suitable mating connector is the Am- bottom panel for added rigidity. The ments shown in Fig. 4. phenol 143 -018 -03. progressive rows of keys are offset Several "key pressed" systems are from each other just as an office type- shown in Fig. 5. All are based on de- 55 -key typewriter keyboard writer is. A long spacebar is also protecting a key being depressed by pull- The full typewriter or teletype vided. It is really three switch contacts ing base current through a common style keyboard is shown in Fig. 6, to allow realiable operation from the transistor. The large capacitor delays the and in the head photograph. This par- middle or either end. Enlarge the end key -pressed command long enough ticular keyboard is modeled more or less spacebar slots slightly. Electrically, we to insure a settled contact. Since the after the ASR -33 teletype, the "stan- have to provide for keys that don't key lets go before the "key pressed" dard" computer entry device used in (continued on page 88) FEBRUARY 1973 RADIO -ELECTRONICS 57

www.americanradiohistory.com DIGITAL IC BREADBOARD DIGI DESIGNER CLOCK toUY'w 410 Lit717 POWER Build It Yourself t, ON

I I

Interested in a quick and painless way to patch together an experimental or development digital circuit about as fast as you can read its schematic? This unique device described last month and concluded in this issue is a logical answer to your problem.

PlU SERS

by JACK LAZES T

LOGICAL AND DIGITAL ELECTRONIC ARE CIRCUITS PERHAPS The following tables list the settings for the FUNCTION - the least understood by most readers. But, experimenting to SELECT switches (S5 thru S8) for the 32 arithmetic /logic func- learn more about them can be a chore when we must find tions: some sort of base for the circuit and then solder the test com- Arithmetic Functions -In this mode of operation, an inter- ponents into the circuit. This drudgery can be turned into a nal "carry" is operative and the "A" and "B" word inputs are pleasure when you use the Digi Designer to breadboard and handled on this basis. Ground IC pins 7 and 8. operate your logic circuits. All components, including diodes, IC's and transistors can be plugged in. All connections are Function -Select Function made without soldering. 32- Function Arithmetic /Logic Computer Circuit- S5 S6 S7 S8 Here's a digital computer circuit that should provide many Gnd Gnd Gnd Gnd F = A hours of educational, as well as entertaining, experimenta- Gnd Gnd Gnd +5V F = A + B tion. The SN74181 integrated circuit is a complete arithme- Gnd Gnd + 5V Gnd F =A +AB tic /logic computer in a single 24 -pin DIP unit. With it you Gnd Gnd + 5V +5V F = Minus 1 (as its 2's complement) can enter two 4 -bit words and perform any of 32 different Gnd + 5V Gnd Gnd F = A plus AB logic and arithmetic operations with them. The desired func- Gnd + 5V Gnd + 5V F = [A + B] plus AB tions are selected by setting four FUNCTION -SELECT inputs ac- Gnd + 5V + 5V Gnd F = A minus B minus 1 cording to the function tables given by the manufacturer. The Gnd +5V + 5V + 5V F = AB minus 1 essentials of these are reproduced below. + 5V Gnd Gnd Gnd F = A plus AB Plug an SN74181 IC into the Digi- Designer. Make cer- + 5V Gnd Gnd + 5V F = A plus B tain it straddles the groove running up the center of the + 5V Gnd +5V Gnd F = [A + B] plus AB breading socket. Supply power to it by connecting pin 12 to + 5V Gnd +5V + 5V F = AB minus 1 ground and pin 24 to +5 volts. Connect pins 3, 4, 5, and 6 to + 5V + 5V Gnd Gnd F = A + A (This results in each bit the common leads of the logic switches (S5, S6, S7, and S8, re- of binary A shifting to spectively). These serve as the FUNCTION -SELECT inputs. The the next more signifi- two 4 -bit data inputs are made to the pins shown in the fol - cant position) + 5V + 5V Gnd + 5V F = [A + B] plus A Input /Output IC Pin Connections + 5V +5V + 5V Gnd F = [A + 13] plus A Binary Value 8 4 2 1 +5V + 5V + 5V +5V F = A minus "A" Word Input 19 21 23 2

"B" Word Input 18 20 22 1 Outputs 13 11 10 9 Logic Functions -In this mode of operation, the internal lowing table with the resultant outputs being read at the pins "Carry" is disabled; thus, each word bit is handled individ- indicated. Observe the output logic levels by connecting their ually, regardless of the logic states of the other bits. respective IC pins to lamp monitors. Connect IC pin 8 to + 5- volts. 58 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com THE DIGI DESIGNER INCLUDES A POWER SUPPLY AND CLOCK GENERATOR and uses them for -u powering and operating the logic and digital circuits you may breadboard. Bounce -less switches. lamp drivers and other circuits ano operating details are in the December '972 issue-

2N5'231BOTTOM IEWi F1 R2 1K ---fp "LOCK. C

«5V IG-I=SN7405 RECT 1 IA, 100 Ply AC

02 CLOCK. 2N5129 R5

1 S

THIS SECTION MAY BE OMITTED IF ONLY A SINGLE OUTPUT IS DE: X11 L Si FRE_, POS 'N NOMI'J.nL '01-03 1N6'4OR 1N148 1 1 Hz 10 II, 100 ur.

1 10 !Ht 100 AHt NO OFF thru 2N5129 All resistors V. watt 10% unless noted 01, 02, 04 Q12- J30, J31. J33, J34- Five -way bind ng posts TIP3055 R1 thru R10 -1000 ohms 03- or 2N3055 J32 -BP' C panel connector SN7405 R11, R13 -100 ohms ICI- Misc : -PC boards. DIP sockets. flase. etc. R12 -100 ohms, trimmer IC2- SN7400 A complete kit of all parts needed to bu Id the R14 -150 ohms D1, D2, D3 -1N914 or 1N4148 Digl- Designer, including a ,:ase, is available RECT R15 -220 ohms -Full -wave bridge rectifier, I amp, 100 piV for $19.95 including postage. An SK -'n R16 thru R19- 22.000 ohms T1 -117 Vac primary, 6.3V seco idary, 1.2A socke and 29 breading pins a-e available fo P6134 All capacitors 15V ceramic unless noted (Stancor No. or equal) 524.9£, postpaid. E. L. Ins ^ruments, Irc., &- C1- 300-,F electrolytic Sl- single pole, 7- position, non -shorting se- First 5'reet, Derby, Conn. 0641E. lector switch C2 -30-µF electrolytic Kit DES-" , consisting of the IC's needed to per- S2, S3 mometary pushbutton C3 -3 -µF electrolytic -spdt form the experiments described n this artic,e C4 -0.3 µF S4 -spst toggle (3- SN:300, 4- SN7490, ano 1- SN74181 se- S5 thru S8 -s C5- 0.03 µF -spdt toggle lected for the computer circuit described C6 -0.003 µF LM1 thru LM5 -5V, 50mA lamps available for $17.95, postpad, from Electron C7, C8- 0.1 -µF 400V SOCKET -EL breadboarding socke SK -10 etics Co., Inc., P.O. Box 278, :ranbury, N.J C9- 3000 -µF electrolytic J1 thru J29 -EL breading pins 08512.

Function -Select Function S5 S6 S7 S8 Gnd Gnd Gnd Gnd F = f4 (Inverter) Gnd Gnd Gnd +5V F = A + B (Nor) Gnd Gnd +5V Gnd F = AB Gnd Gnd + 5V + 5V F = Logical 0 Gnd + 5V Gnd Gnd F = AB (Nand) Gnd + 5V Gnd + 5V F = B (Inverter) Gnd + 5V + 5V Gnd F = A G B (EXCLUSIVE-OR) Gnd + 5V + 5V + 5V F = AB +5V Gnd Gnd Gnd F = A + B + 5V Gnd Gnd + 5V F = A B (EXCLUSIVE -NOR) +5V Gnd +5V Gnd F = B + 5V Gnd + 5V + 5V F = AB (And)

+ 5V + 5V Gnd Gnd F = Logical 1 +5V +5V Gnd +5V F = A + B + 5V + 5V + 5V Gnd F = A + B (oR) +5V +5V +5V +5V F = A NOTE: A + B is read "A or B` AB is read "A and B" Comparator Functions A is read "not A ". Function -Select IC Pin If Lamp This Means The bar over a letter or a number indicates a NOT function, so B is S5 S6 S7 S8 No. 7 is That read as NOT B. Gnd + 5V + 5V Gnd Gnd On A ' B The plus sign within a circle indicates an EXCLUSIVE OR operation. Gnd + 5V + 5V Gnd + 5V On A < B Plus signs represent logical OR operation whereas arithmetic Gnd + 5V + 5V Gnd Gnd Off A > B functions are spelled out. Gnd +5V +5V Gnd +5V Off A a B These are logical expressions in Boolean algebra. In addition to the arithmetic and logic functions shown I think that these examp'es have shown you how you can above, the SN74181 computer circuit also provides a versatile make use of your Digi -Designer to conveniently design, as- digital comparator function. Connect IC pin 8 to ground, IC semble. and test relatively complex digital circuits, even a

pin 16 to one of the lamp indicators, and IC pin 7 as shown i1 small computer, without soldering . . . and in only a few the following table: minutes. R -E FEBRUARY 1973 RADIO -ELECTRONICS 59

www.americanradiohistory.com the state of SOLI STAT

Of prime interest this month are a bunch of new IC's. The most exotic include a complete transmitter on a chip and a pressure transducer.

by LOU GARNER SEMICONDUCTOR EDITOR

IF YOU'VE EVER CONSIDERED ASSEM- bled in a 10 -pin hermetic TO -100 circuit consists of transistors Q1, Q2, bling a subminiature AM transmitter, package. Its functional block diagram Q3, Q4, Q5, Q6 and Q7, plus diodes chances are you've thought in terms of is given in Fig. 1 -a, its internal D1, D2 and D3. Q8 is used as the os- a barely stable, limited performance schematic in Fig. 1 -b. As shown, the cillator and may be crystal -controlled. modulated oscillator using one or two device comprises an oscillator, two rf Q12 and Q13, together with diodes D4 transistors. After all, a subminiature buffer amplifiers, a power output and D5, make up the rf buffer ampli- design is not compatible with the stage, a combination audio preamp or fiers, while Q15 is the final power out- handful of components needed for a code generator, a unique trans - put stage. The audio preamp, which crystal -controlled oscillator, buffer am- formerless modulator, and a latching - also can be used as a tone coding gen- plifier, power stage, audio preamp, type power regulator using a total of erator, consists of Q9, Q10 and Q11, and modulator. No longer! 16 transistors, 5 diodes and 9 resistors. with Q14 serving as the driver and A new semiconductor device re- Designed for operation on dc power Q16 as the final stage modulators. cently introduced by a West Coast supplies furnishings from 3 to 15 volts, A typical 27-MHz AM transmitter manufacturer, Lithic Systems, Inc. the LP2000 is capable of supplying up circuit, as suggested by the manufac- (10010 Imperial Ave., P.O. Box 869, to 100 mW of pulse modulated or CW turer for the LP2000, is illustrated in Cupertino, Calif. 95014), permits the rf or a 50 mW AM signal at 27 MHz. Fig. 2. According to Lithic Systems, assembly of a subminiature design Its intended applications are in hand- this design can furnish 100 mW CW with all the operational features, ex- held, mobile, airborne and marine output, requiring 50 mA from a 12- cept for power output, of a com- two -way radio equipment, as well as volt supply, or 50 mW when operated mercial quality multistage transmitter. in R /C, biomedical monitoring, secu- as an AM transmitter, using 28 mA Called "the world's first radio rity alarm, and short -range telemetry from its dc source. In the AM mode, transmitter on a chip," the new device, systems. it will accept up to 90% modulation designated the type LP2000 Micro - Referring to Fig. 1 -b, the with less than 10% distortion. transmitter, is a monolithic IC assem- LP2000's power supply regulator /latch Available in quantity directly

lo OSCILLATOR BIAS/ LATCH TRIGGER

OSC. R7 TUNE RF OUTPUT 2 OSCILLATOR BUFFER OUTPUT 3

OSC. FDBK. LP2000 OUTPUT BYPASS

POWER SUPPLY MOD. MODULATOR/ REGULATOR/ PREAMP OUTPUT REGULATOR LATCH

III 1 5 6 7 9 8 GND. +Vcc AUX. MOD. MOD. INPUT/ LATCH PREAMP BIAS SET OUT. INPUT b

FIG. 1- FUNCTIONAL (a) AND SCHEMATIC (b) diagrams of the LP2000 microtransmitter IC. 60 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com +12 50 OHM ohm loads on each of its two channels Motorola Semiconductor Prod- VOLTS TRIGGER ANTENNA while providing complete short -circuit ucts, Inc. (P.O. Box 20912, Phoenix, VCC OFF ON protection and thermal limiting. It has Ariz. 85036) has introduced four new r° an input impedance in excess of IO meg- high- threshold logic (or HTL) IC's in- OSCI LLATOR ohms, making it ideal for use with ce- tended for use in demanding com- TANK OUTPUT ramic phono cartridges. Assembled in an mercial and industrial applications, TUNE TANK 8 -pin dual -in -line batwing heat sink such as machine tool and process con- OSC. package, the LM377 can provide 100 dB trollers, computer peripherals, appli- OUTPUT gain with a maximum distortion of only ances, measuring and dispensing RFC TUNING 0.5% at 1 kHs. It is designed for opera- equipment, and so on. The new de- tion on an 18 -volt dc source and has an vices include the MC686, a 4 -bit shift internal power supply regulator. register, the MC684, a decade counter, OUTPUT BYPASS Identified as the MM5314 series, the MC685, a binary counter, and the National's new digital clock IC's con- MC688, a dual J -K flip -flop. With a tain all of the counting, decoding and typical switching threshold of 7.5 volts MOD. IDLE multiplexing circuitry required for 4 -or and a dc noise margin of (typically) 6 MICROPHONE ADJ. CURRENT ADJ. 6 -digit electronic clocks. Intended for volts, all are designed for 13" DYNAMIC four units SPEAKER) operation on a single 11 to 19 -volt operation on a 15 -volt dc source. FIG. 2- SCHEMATIC OF A COMPLETE 27 supply and a half -wave rectified 50 or Shown in Fig. 5, each of the four new MHZ AM transmitter using the LP2000. 60 Hz input, the new devices are de- HTL devices is available in either from the manufacturer, the LP2000 & as odes .. Comaataala oath motor, a may be purchased in small quantities ÇnietrLa Cepa. _ atat arat _ .. Elactut and single units from Circuit Special- tsunt r.,ihts, a,rl ,ptl"cUm, boa. f ['s MNTL, a log ev.rh CMOS . _ Otto-thy a ists (P.O. Box 3047, Scottsdale, Ariz. prom Noirvr nn yn.l upWY or ara 85257). The distributor's single unit price is $16.00, plus postage and, if applicable, sales tax. tors Product /device news MHTL, a lojlc coop, The National Semiconductor Cor- Support equlp,ncn r. poration (2900 Semiconductor Drive, Nose on your PO Santa Clara, Calif. 9505 I) has introduced a number of interesting new FIG. 5 -HTL DEVICES RECENTLY IN- devices, including the world's first TRODUCED by Motorola. semiconductor absolute pressure trans- FIG. 3- NATIONAL SEMICONDUCTOR'S ducer, a dual audio amplifier IC, and LX1600A absolute pressure transducer IC. black plastic or ceramic DIP's. De- a complete digital clock circuit on a pending on type, unit prices range single monolithic chip. from $2.55 to $6.30. Intended for a wide range of ap- TTI.ASI A new high -voltage display- driver plications in fuel metering and igni- IC is now available from Precision tion controls, heating, refrigeration, Monolithics, Inc. (1500 Space Park automotive safety and diagnostic con- Drive, Santa Clara, Calif. 95050). Ex- trols, utility metering and fluid or hibiting the highest breakdown volt- pneumatic systems proportional con- ages yet attained by a conventional trols, the new pressure transducer, des- linear processing technique, the new ignated type LXI600A, contains four device, Fig. 6, is designed to drive the functional transduction elements in a single hybrid IC package- diaphragm- vacuum reference, a piezoelectric sensor, a signal discriminator-conditioner, FIG. 4 -TI'S NEW SN54/74284 AND and a signal amplifier -processor. The SN54/74285 digital ICs. first three elements are contained in one silicon die, while the fourth is provided by a standard linear opera- signed to work with inexpensive plas- tional amplifier. Illustrated in Fig. 3, tic transistors for digit and segment the LXI600A is supplied with a cali- driving of standard LED's or in- FIG. 6 -MONO DRV -01 HIGH VOLTAGE DIS- brated range between 0 and 15 psi, candescent displays. PLAY DRIVER now available from Precision Monolithics, Inc. but can be used up to 27 psi. In op- Two new TTL /LSI IC's from eration, the device is equivalent to a Texas Instruments, Inc. (P.O. Box simple potentiometer without loading 5012, Dallas, Tex. 75222) can be used cathode segments of high -voltage gas problems, having an input impedance together to generate an eight -bit bi- discharge displays, such as the Bur- in the thousands of ohms and an out- nary product in only 40 nanoseconds. roughs Panaplext and Sperry numeri- put impedance measured in megohms, Designated types SN54/74284 and cal display devices used in miniature thus providing protection for both in- SN54/74285, these 4- bit -by-4 -bit par- calculators and electronic test input overvoltage and output short cir- allel binary multipliers each contain struments. Identified as the cuits. The device's maximum output is the equivalent of over 200 gates on a monoDRV -01, the new unit is corn- 5 mA, its maximum excitation voltage monolithic chip. Illustrated in Fig. 4. patible with MOS logic and has a 30 Vdc. the new units are fully TTL /DTL guaranteed breakdown of 145 volts National's new dual audio ampli- compatible. The devices are offered in (160 volts typical), compared to the fier, type LM377, can provide up to 2 16 -pin plastic and ceramic DIP's as previous industry maximum in the 80 watts of continuous ris power into 8- well as in ceramic flat packs. volt area. R -E FEBRUARY 1973 RADIO -ELECTRONICS 61

www.americanradiohistory.com step -by -step TV TRAF I

Proper agc action is a prerequisite for a television picture with optimum brightness and contrast. Here is how the all-

by ART MARGOLIS keyer collector circuit. The dc that is amplifier and considers it a trouble varying slightly as a result of the suspect when agc trouble is occurring AS MENTIONED IN AN EARLIER ARTICLE height of the horizontal sync pulse in and the keyer has been exonerated. concerning the agc keyer, (Radio -Elec- the video, is applied to the base of the Strong local channels are coming in tronics, September, 1972) there are agc amplifier from a voltage divider overloaded, or not at all, while the two more agc stages, the agc amplifier consisting of a 5000- and 33,000 -ohm weak distant channels are being dis- and the agc delay. This month we'll resistor. played fine. Sometimes the weak discuss the agc amplifier. The delay The agc amplifier is forward channels are blanked out. will be covered in a future article. biased by voltage from the plus 12V The technician has been to the Why have the amplifier and the source. The voltage is developed as first test point, TPI, the negative end delay? Why not just use the varying current flows from the base to the of the 8 -µF filter capacitor. Two dc dc control voltage that comes out of emitter and through the 470 -ohm readings were taken there. One with a the agc keyer and apply it directly to emitter resistor to the 12V source. The strong channel tuned in and the other the rf and i.f. amplifiers to keep total base is driven from the keyer through with the channel selector cocked be- gain constant? R 1. Resistor R2 isolates the base from tween two channels. The on channel It's because agc has to always be the emitter. reading was between 5 and 7 volts applied to the i.f. stages but only The dc voltage from the keyer while the off channel reading was 12 sometimes applied to the if stage. The varies with signal strength. As signal volts. The keyer is cleared of trouble. rf amplifier output is critical. To strength rises, the forward bias on the The next test point is TP2, the maintain a snow -free picture, it must agc amplifier increases. As a result, junction between the 15.000-ohm and be strong. That way it produces a high collector current increase makes the TYPICAL AGC AMPLIFIER CIRCUIT if-mixer noise ratio. Such a high ratio collector more positive in voltage. A I.F. overrides mixer noise and a snow -free higher positive voltage is applied to JUNCTION display is assured. the i.f. amplifiers and the delay. This AGC 1.5 VOLTS Therefore the following agc ac- tends to make them have a strong agc NO SIGNAL tion is desired. On strong signals agc control. 1ST I.F. 2ND I.F should be applied to both rf and i.f. As signal strength drops the am- 2.5 VOLTS WITH SIGNAL During medium strength signals agc plifier forward bias decreases. This R4 R5 should be applied to the i.f. but not makes the collector less positive in 1K 1K the rf. When a weak signal is received voltage. Therefore less plus voltage is TP2 no agc should be applied to the rf and applied to the i.f. amplifiers and de- R6 little to the i.f.'s. lay. This tends to reduce the agc con- or none 12 VOLTS The agc amplifier takes the trol. NO SIGNAL keyer's dc output and analyses it. Dur- The agc delay won't turn on un- 7 VOLTS ing strong signals the amplifier sends less the amount of plus voltage is rela- WITH SIGNAL plenty of signal to the delay and the tively high. The i.f.'s are controlled i.f.'s. The delay turns on and sends a even though the agc amplifier voltage control voltage to the rf. is not positive enough to turn on the TP1 When medium signals are re- delay. ceived, the amplifier sends enough Typically the emitter voltage is AGC voltage to the i.f.'s for control but not around 10V. The base is about 9.3. KEYER enough to the delay. The delay does This gives the pnp transistor a forward not turn on and lets the if amplifier bias of around 0.7V. When this bias is run wide open. present the collector ends up with Cl 8µF When weak signals are received, about 5V. This is obtained from the the amplifier produces little or no out- 12V supply through resistors R6 and put and neither the rf or i.f. are con- R7 in series. T trolled. They both run at maximum V gain. Agc amplifier troubleshooting +12V The agc amplifier circuit consists SOURCE Typical transistor agc amplifier of all components clustered around its SUPPLY Is used almost univer- input and output. It does not include AN AGC AMPLIFIER The agc amplifier receives a fil- sally In solid -state TV sets. Its purpose Is to tered dc control voltage from the neg- the i.f.'s, delay or keyer. amplify and Invert -when necessary -the keyer. ative end of the 8-1.LF filter in the The technician arrives at the agc varying dc voltage developed by the agc 62 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com that is snow -free with good horizontal and vertical sync along important agc amplifier works in solid -state TV sets.

10,000 -ohm agc amplifier collector re- resistor back in the circuit and care- base, emitter and collector. Voltage sistors. The strong channel and off fully disconnect the emitter of the agc tests are next, with the collector first channel readings are made. One of delay. Then read the test point once in line. three things is noted. The vtvm shows again. If the test -point voltage remains A reading is made and the col- normal readings, there's a constant the same now, the trouble is in the lector, when not normal, is either high low voltage or a constant higher volt- delay circuit. However, if the test - or low in voltage. Since current flows age. The trouble chart shows the three point voltage rises high, then the agc from the i.f. amplifier bases and the pathways. You have arrived at a diag- amplifier is the guilty party. delay emitter to the amplifier col- nosis except if a constant higher volt- Once the agc amplifier circuit be- lector, they must pass through the age is read, then there is excessive agc comes the known guilty party, the end 10,000-ohm resistor on their way. The control and you go to its next step. of the job is to locate and replace the 15,000 -ohm resistor is an isolation re- One side of the 10,000 -ohm resis- bad part. sistor between the amplifier collector tor is unsoldered and a dc voltage The agc amplifier is the pnp tran- and positive 12-volt source. Note the reading made at the junction. sistor with 15,000 -ohm and 10,000- emitter is at + 10 volts. The voltage will be near source or ohm collector resistors, 470 -ohm emit- Collector high -If the collector is around a volt or two. If it is near 12V ter resistor and the 33,000 -ohm base high then the 15,000 -ohm resistor be- source, then the video i.f. stages are at resistor. The 5000 -ohm resistor is also comes the prime suspect. It could have fault. If the voltage is low the agc am- involved, but it is really part of the shorted. plifier and delay become the suspects. keyer collector leg. Another possibility is that Q3 is The next step is to resolder the The test points now become the conducting too heavily drawing more BLOCK DIAGRAM T AGC ACTIVITY

TUNER IF STRIP MIXER RF 1ST 2ND 3RD LOCAL AMPL AMPL AMPL AMPL IIPPT OSC VIDEO

AGC DELAY f

DC CONTROL VIDEO AGC VOLTAGE AGC AMPL KEYER AMPL

FLYBACK WINDING

AnonFLYBACK PULSE

FEBRUARY 1973 RADIO -ELECTRONICS 63

www.americanradiohistory.com _

x ear

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CREI offers Electronic Engineering Technology programs through home study. You have a choice of eighteen different program arrangements so you can specialize in exactly the area of electronics you want. All of the programs, except a brief introductory course, are college - level.

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www.americanradiohistory.com SYMPTOM - STRONG CHANNELS DEFECTIVE, WEAK CHANNELS NORMAL on the emitter. The shorting, leaking (SOMETIMES BLANKED OUT) or opening up of the transistor can NO TEST NEG END OF, TP1 YES make the emitter voltage disappear, STRONG CHANNEL 5 TO 7 V drop or rise to plus 12 -volt source. OFF CHANNEL 12V

KEYER HAS TROUBLE TEST JUNCTION R6 AND R7, TP2 STRONG CHANNEL 2.5V CONSTANT HIGHER OFF CHANNEL 1.5V VOLTAGE. EXCESSIVE AGC YES -GOOD AGC

UNSOLDER ONE END TEST VIDEO LF.'S OF R7, TEST JUNCTION TEST AGC DELAY TP2 R6 AND R7 AGAIN NEAR 12V

ONE OR TWO VOLTS

TEST I E.'S

AMP AND DELAY OVERLOADED -NO AGC VOLTAGE. Picture Is INDICATED out of sync and shows signs of overload. CONSTANT LOW VOLTAGE. NO AGC RESOLDER R7 UNSOLDER EMITTER OF DELAY

TEST JUNCTION TP2 AGAIN

STILL READS ONE OR TWO VOLTS NOW READS TEST AGC AMPLIFIER, HIGHER R6, R7, R3, R2 AND R1

AGC AMPL WASHED OUT -TOO MUCH AGC VOLTAGE. Rf TEST TEST TEST and I.f. amplifiers are tending to cut off.

BASE VOLTS EMITTER VOLTS COLLECTOR VOLTS Base -The base voltage is tied in with the keyer collector circuit. Since _L_ the keyer has been exonerated, the HIGH HIGH base circuit is practically given a clean NONE, OR NONE OR NONE OR NEAR 12 NEAR 12 HIGH bill of health too. The 33,000 -ohm re- LOWERED LOWERED LOWERED VOLTS VOLTS sistor could possibly cause the base voltage to rise, if it shorts. Usually though an incorrect base R6, R7 R6 SHORTED voltage in this case only R2 OR 03 R3 OR Q3 R3 OR Q3 could happen Q3 OR 03 R3 SHORTED OPEN SHORTED Q3 OR if either the emitter-base or base -col- OPEN OPEN lector junction shorts. Then the volt- TWO TROUBLESHOOTING CHARTS help loca e and repair the trouble speedily and efficiently. age could change. R -E The top one localizes the trouble and the bottom one helps to find the defective component. electrons from the i.f.'s and delay. voltage will drop all the way to zero. This increases the positive voltage on Emitter -The emitter has one the collector. component attached. If the 470-ohm Q3 can conduct too heavily if it is resistor opens the emitter loses its 10 leaky or shorted, or the 470 -ohm emit- volt potential. Should the 470-ohm re- ter resistor becomes shorted. sistor short, plus 12 volts will appear Collector low -When the collector is low, then the flow of current from the i.f.'s and delay has lessened. The collector becomes more negative, or less positive. This can happen if the conduction of the transistor is lessened or turned off. If the 15,000 -ohm resistor opens then the i.f.'s lose their base forward bias and the delay loses its emitter or forward bias. The i.f.'s and delay turn off. The amplifier collector loses its positive voltage and the amplifier turns off. When the transistor or resistor R6 THE PICTURE BENDS -NOT ENOUGH AGC. or resistor R7 opens, the collector Video Is too strong and beginning to overload. "What do you mean, your set `fixed itself' ?" 68 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com two -in -one light meter

This instrument combines an ordinary light meter with a color- temperature bridge. It will give you both the quality and intensity of your light

by HAROLD PALLATZ

THIS UNIT COMBINES A SIMPLIFIED color - made under sunlight or fluorescent made no attempt to do so, it is possible temperature bridge' with a light -in- lights. Since batteries make up the other to calibrate your meter dial directly in tensity meter. Simply flip the switch to two arms, and their impedance is low, degrees K (Kelvin). convert from one to the other. Three bridge sensitivity is maximum. While I The light intensity meter is conven- convenient light- intensity ranges permit tional. The two CdS cells are in series making measurements from the weak- MATERIALS LIST with the meter and a single battery. The Meter, 50.0 -50 microamperes. Calrad CMO 38-3 to very second battery (Fig. 2) is connected in est high intensity illumination. Case, 4" x 2'/e" x 1%". Olson Radio CA 356 Total construction cost is just over $1.09 reverse through a calibrating resistor to $10.00. Photocells (2), cadmium sulfide. Resistance bias the meter from its normally zero A little additional experimenting range 200 ohms to 1 meg, sensitivity 500 -600 center position to full left scale deflec- Angstroms. 150 Vdc max, 150 mW. Olson Ra- tion with zero light intensity. Thus the resulted in a truly "starved circuit," re- dio TR -091 986 pair ducing the number of components to Switch, slide type, dpdt with center OFF posi- full meter swing can be realized. The the minimum: a single resistor, a pair of tion. Calrad SS -7 circuit serves a second function, that of cadmium sulfide (CdS) cells (98C pair), Penlight cells (2), leakproof type. Size AA a battery check. The batteries should be Resistor, calibrating (approx) 18,000 ohms, '/z when full left deflection is a meter and two penlight cells. In spite watt changed off of the lack of complex parts, the accu- Red filter* Note; these filters can be made with by more than one division. Under nor- racy will compare favorably with ex- transparent dial light dip paint. mal conditions, you should realize al- pensive laboratory type instruments. Blue filter* most as normal shelf life (one year) of Parts may be purchased at Olson Electronics the 260 S. Forge Street, Akron, OH 44327, Radio batteries. Circuit theory Shack Corporation, 730 Commonwealth Ave., The basic range of our instrument The color temperature meter, uses Boston, Mass. 02215, and Lafayette Radio, was found to be 8 foot -candles (at full two filters, a red and a blue. Place one 111 Jericho Toke., Syosset, L.I., NY 11791 scale). A white cardboard disk (Fig. 3) *Filters are also available from Edmund Scien- over each CdS cell. These form a bridge tific Company, Barrington, NJ 08007 circuit (Fig. 1). The other two arms of For red use Edmund No. 82,015 (Medium the bridge are the penlight batteries. Red). For blue use Edmund No. 82,033 (Light Under balanced conditions (where the Blue). They come in sheets 20 x 24 inches and are $2.50 each. Also available from Edmund is 5" is amount of red light equal to the a small Color Filter Sample Book. This has all s amount of blue light), the zero -center their colors (size 1 x 4) and costs $1.50. (use microammeter will read center (or No. 40,675 for ordering the book). zero). Should there be more red than blue light, the meter will deflect to the %//// /// %/// / / //. left according to the amount of un- FIG. 3 -RANGE EXTENDER, three shields that balance. Thus readings made under let the filters get more or less light. tungsten lamps will differ from readings was cut out to increase the light range RED BLUE 10 times (0 to 80 foot -candles). I used the cardboard wrapper of CONTAC Cold FILTERS Capsules. It is also possible to use a piece of metal with small holes pierced CdS CdS in it. For the HIGH range (0 to 800 foot - 50ß-50 "ADJUST VALUE OF RCAL (APPROX. 18K) candles), I drew India ink stripes on a TO READ sector of the disk. The first results with 1.5V 1.5V EXACTLY FULL SCALE (AT FULL LEFT) WITH ZERO LIGHT the ink showed that too much light still ILLUMINATION ON Cd CELLS. passed through the cardboard, so some

FIG. 1 -COLOR TEMPERATURE METER is a FIG. 2 -LIGHT INTENSITY is measured by one black plastic tape was added. This did bridge that balances red and blue light. cell; the other supplies a bucking voltage. the trick. FEBRUARY 1973 RADIO -ELECTRONICS 69

www.americanradiohistory.com Construction f//////// mination levels, do not expect con - sistant color temperature results.2,4. Use template (Fig. 4) for the panel The L light intensity range is most layout. A battery clip cannot be used easily calibrated by direct comparison because the Olson meter case is a with another light meter. Your local squeeze fit. Solder the wires directly to photographic store may let you corn- the battery terminals. Solder fast, using pare your meter with theirs. Our meter a minimum of heat, or battery life may turned out to have a basic 0 -8 foot - be reduced. The meter hole required candle range. Your range will depend proved to be 1/32 -inch larger than a upon the CdS cells used, their place- standard 11/2-inch socket punch. Use a ment inside the case and a number of half -round file and apply muscle! The other factors such as case opening size, slide switch (must be of the center OFF meter sensitivity, battery voltage. You type dpdt), requires a 1/4 x '/-inch rec- can use the table for a cross-check of illu- tangular hole. Drill quarter -inch holes FIG. 5- COMBINED CIRCUIT, wi h a dpdt mination light values2,5. The light in- switch. Center position of the switch is OFF. tensity values can be made into a refer- Q ence chart or marked directly on the gram. Always use fresh new batteries. meter face. Our battery is held down with a piece of stiff wire (taped to the batteries) and Applications wrapped around the slide switch In color photography, it is very im- mounting screws. Transparent tape is portant to know the color temperature used to hold the CdS cells in place, the of the light source if perfect color pic- tape holding the cells to the meter tures are to be made. This may be easy mounting screws. when photographing under a noonday sun, but what is the temperature at early Calibration morning or at sunset? Your meter will The color balance meter may be give an instant answer. Also when sunlight is mixed with fluorescent or tung- Color- temperature chart sten light the color balance of the light of common light sources must be measured accurately if the best results are to be achieved. You can also Color Temp test out the color value of photographic (°Kelvin) Source filters by inserting the filter in front of 1900 Plumbers candle the meter and noting the readings. You 2760 40 -watt tungsten lamp can also check your 3,200° K color pho- 2865 100 -watt tungsten lamp tography lamps to see how close they 3200 G -E Mazda 3,200K lamp are to new condition. 3400 Photoflood lamp The photographic applications for 3000 Warm white fluorescent the intensity function will be numer- 4500 Cool white fluorescent ous2'5. You can use it for enlarging by NO. 6 6500 Daylight fluorescent placing the meter directly on the easel CLEARANCE 5400 Noonday sun and adjusting the diaphram for some FIG. 4- TEMPLATE FOR METER PANEL. 6500 Overcast sky known reading. A constant meter reading will mean a constant exposure time. and file to shape. After all work is corn - calibrated directly in degrees K (Kelvin) Twice the light reading means that the pleted on the panel, go over its surface by using the table. Where maximum exposure should be cut in half. You can with fine steel wool to remove nicks and precision is desired, make this calibra- also use the meter for picture taking 3, scratches and provide "tooth" for the tion at some constant level of illumina- but a discussion of the various exposure paint. We used Dove Grey (Krylon tion (such as 4 C.P. or half scale on the times, f stops and film speed relation- 1605) spray enamel to finish the panel. meter), by sliding the switch to the L ships are beyond the scope of this ar- Use press -on decals for the lettering. setting. Then return to the c setting for ticle. It is possible to purchase a small The red and blue filters may be made the color calibration. Noonday sunlight exposure -guide calculator in most photo of sheet cellophane, or purchased glass is 5,400° K. An overcast sky runs 6,500° shops and convert your meter readings filters may be used. You can also use K. A photoflood lamp is 3,400° K, a directly to exposure values by using transparent paint (such as General Ce- 100 -watt tungsten lamp 2,865° K. them together. R -E ments Dial Light Color Kit 66-6). I sug- Where a particular color temperature References gest that rather than coat the face of the falls on your meter dial will be primar- CdS cell directly (it might craze the ily related to the red and blue filter you 1. Zworykin and Ramberg, Photoelectric- plastic shell), use transparent tape and have used. Thus every instrument will ity and Its Applications, 272, bridge cir- coat that instead. Both the red and blue read somewhat different. Once cali- cuit for determining color temperature should transmit light approximately brated, the repeatability will be good of a lamp. equally. You can check the light trans- and reference chart can be made up and 2. Ibid, page 19. Temperature and bright- mission by switching your meter to L pasted on the bottom of the meter case. ness table. and placing a filter in front of both cells. If you wish, it would be possible to cali- 3. Ibid, pages 292 -293, measurement of Then try the other color. Readings brate the meter dial directly. This is not photographic exposure. should fall within one meter division. advised -you must be very careful when 4. Clark, Walter, Photography by Infrared, The photocells were set in the top of the removing the protecting meter cover - John Wiley & Sons. Page 139, color case, near the front, close enough to- the slightest dust or iron filing will im- temperature table. gether so that they would be covered by pair meter operation. The color balance 5. Barrows, Light, Photometry and Illumi- any section of the light extender. readings will hold true for a wide range nation, McGraw Hill Co. (1912). Page Fig. 5 is the complete circuit dia- of light intensity levels. Near zero illu- 38, brightness of light sources table.

70 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com R -E's Service Clinic

LET'S HAVE A FEW WORDS ABOUT IN- There's a division here. If the in- Intermittents -how termittents. Not the words normally termittent shows up within a short used around the shop; this magazine time after the set's turned on, say 5 to to locate them must go through the mails. First, let's 10 minutes, the chances are that it is look at a few facts about these in- in some part which generates its own furiating things. heat; a current- carrying resistor and so An intermittent is just that; some- on. Solder joints are frequent offend- A little heat, a thing which makes intermittent contact ers in this category. little cold -fine in a circuit. It can be a short, but The other and much more diffi- most of the tougher ones seem to be cult type, is the long -term intermittent. intermittent locator opens. They can be broken down into These show up at irregular intervals, two general types -the "physical" or from hours to days. They're also ther- jar -intermittent, where you can make mal, but are caused by "conducted" by JACK DARR it act up by tapping the chassis; and heat, from other parts on the chassis SERVICE EDITOR the thermal, caused by heat. getting hot. This heat is conducted The `jar" intermittents are much through the chassis, or the air. In easier to find. By tapping the chassis "touchy" intermittents, the frequency very carefully you can find the most of cut -out often depends greatly on "sensitive" area, and from this point, the ambient temperature. (We'll show it's not too hard to locate a guilty part you a real wowser like this in a mo- or solder joint. The eraser of a lead - ment!) pencil makes a dandy tapper. In both types, heat is the trouble- Thermals are tougher. Even in a maker. It causes physical movement of transistor chassis, you're going to find the part, making or breaking contact. thermal intermittents. This is espe- This can be as little as a thousandth cially true of those "long- term" inter - of an inch, if it's inside a resistor, coil, mittents that cut out once a day. or capacitor, but it's enough! Printed - Something in there is getting hot and circuit board solder joints are frequent expanding. The circuit opens (or offenders. A "pocket joint" (see dia- shorts to other parts) and there you gram) can make perfect contact. But if are. In the standard thermal no amount of jarring the chassis (or kick- WIRE LEAD FROM PART ing the cabinet) will faze it. "POCKET" There are a couple of tricks you JOINT can play on these. One is running the set with the ac line voltage just a little above normal. This won't hurt anything unless you leave it on for too long. The high line voltage will raise the dc voltages. It will also raise the temperature of things and make the BOARD This column is for your service intermittent more apt to act up. If this NICE ROUND problems radio, audio or gen- doesn't work, try running it with line BLOB OF -TV, SOLDER!! eral and industrial electronics. We voltage a little below normal. This answer all questions individually by leaves things a little cooler than they the board expands slightly, whammo. mail, free of charge, and the more in- usually are. If you suspect this, you can "get out teresting ones will be printed here. Determine the characteristics of the shotgun "; remelt and resolder all If you're really stuck, write us. the trouble. Does it cut out once a solder - joints in the area of the trouble. We'll do our best to help you. Don't day, every 2 -3 days, every hour or so, You may never know which one it forget to enclose a stamped, self -ad- etc. Questioning the owner is a very was, but you'll fix it. dressed envelope. Write: Service Edi- good way to get this information. If tor, Radio -Electronics, 200 Park Ave. this is a long -term intermittent, and ir- Isolation South, New York 10003. regular, the chances are that it is a The first thing you must do is thermal. isolate the area of trouble. From the FEBRUARY 1973 RADIO-ELECTRONICS 71

www.americanradiohistory.com characteristics, you know about where ier. The spray -can coolant is a very Turning it on, I waited. This time, it it is; that is, signal circuits, sync, useful weapon for locating inter - started to flicker in only about 20 sweep. Observing the characteristics mittents. minutes. A quick check with the scope will give you clues. Now, check every Here's a good example. I had a and a crystal- detector probe showed a part of the circuit that could affect Zenith color TV set on the bench. The steady signal at the i.f. input, and a that particular function. picture flickered on and off at highly severe flicker at the video detector Now, see if you can make it show irregular intervals, leaving a white output. So, I had it pinned down; it up. To do this, you can either apply screen. This was a very fast flicker, was in the i.f. (Clamping acc made no more heat, or less heat -cool it. The sometimes repeated three or four difference.) reaction to these tests will give you a times. After doing this, it would play Now I made thermal tests. With a lot of data and that's what you need. for a couple of hours. In fact, it sat on junk hair -drier which still worked, I You can apply heat with a heat -lamp, the bench under observation for two blew hot air on the i.f. stages. On the or by touching the suspected part with days; no flicker! Fortunately for my first and second stages, no result. As the tip of a soldering iron, or by production ratio, I was working on soon as I hit the last i.f. stage and de- blowing hot air on it with a heat -gun other things at the same time! tector, wham! It started flickering like or old hair -drier. Cooling is much eas- Then I got after it in earnest. mad. To verify this, I blew spray coolant on it. The picture came back as steady as a rock. Now I had it. The i.f. stage in these sets can be taken out in toto, by pulling off some push -on connectors and taking out three screws. Making up a set of connecting leads, I put it on the bench and turned it on. Despite a tendency to oscillate, it worked well enough for testing. I checked each part in the output stage, by touching it with the tip of a soldering iron. When I hit the output transistor, out it went! Verifying this, I sprayed the thing with coolant. It came back on. Replac- ing this transistor cleared up the trouble. Hooking the original transistor to a curve tracer, it checked perfectly. Heating it with the soldering iron, in about 20 seconds it went to the horizontal line; it was opening up internally! Spraying it with the coolant brought it back again. I could repeat this as often as I wanted to. For a definite check, I warmed up my replacement transistor with the soldering iron. Absolutely no change in the picture. About this time, someone will say "But you'll ruin those delicate transistors, heating them up like that with a soldering iron." To which I can reply. Perma -Power Color Brite "Possibly so. However, I have never VIEW- damaged one yet with this method, When the picture looks good, and I've tried!" I will admit that I've been guilty you look good. of saying that there was no such thing as an intermittent transistor. I stopped When a color TV picture fades, or when the black- and -white is erased by a this; people kept sending me inter- cathode -to- filament short, you can save the day, and the tube, by installing a mittent transistors, and I kept finding Perma -Power Britener. them in sets I was working on. Boost models bring out lost sharpness both jobs with a Color -Brite Combina- They can be thermal. In fact, a and detail by providing increased fila- tion Isolation and Boost Britener. post -mortem analysis of the case of ment voltage to increase electron There are Perma -Power Color Brite the Zenith brought out an interesting emission. Full contrast and color qual- models for both round tubes and rec- fact. The reason it sat on the bench ity return immediately. tangular tubes. In fact, Perma -Power and played for two days was that dur- Isolation models restore the black - has a Britener for just about every pic- the conditioner and -white information that gives a ture tube ever made! You'll look very ing those days shop air- color picture its quality, by isolating the good to your customer when you pro- was running, and blowing right at it! short, thus restoring black- and -white long the life of the expensive picture On the day that it started cutting out, video drive. tube. Pick up a supply of Color -Brites the air conditioner was turned off!

Short now . .. fade later? Handle from your Perma -Power distributor! This comparatively small difference in the ambient temperature was enough to make it start acting up. PERMA -POWER DIVISION ways you can go CHAMBERLAIN MANUFACTURING CORPORATION There are many this kind of trouble; don't ne- 5740 North Tripp, Chicago, Illinois 60646 after PE (continued on page 78) Circle 20 on reader service card 72 RADIO- ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com Up- to- the -minute service information* from Sams *Selected portions of manufacturers' servicing data bound in convenient book format Transistor Radio Modular Hi -Fl /Stereo Scanner -Monitor Servicing Data Servicing Data Servicing Data Designed for the service tech- What the transistcr radio series Contains comprehensive servic- nician, Sams Transistor Radio does for transistors, this series ing data for 30 of the most popular volumes are published monthly. does for hi -fi and stereo com- UHF and VHF receivers now in Each volume in the series con- ponents and compacts. Issued use, including B&K, Browning, tains schematics, parts lists, monthly, each volume includes Johnson, Midland, Pace, Pearce - pictorial presentations, trouble- schematics, pictcrial presenta- Simpson, Penneys, Realistic, So- shooting data, plus other infor- tions, pertinent servicing data nar, and Teaberry. As the first mation on up to 17 of the latest and parts lists for up to 13 of the guide ever released for scanners transistor radio receivers and latest modular components - and monitors, it is an invaluable other youth products. Includes tuners, receivers, amplifiers, etc. aid for service technicians. Its data you need to service virtually Covers virtually all equipment last- minute information includes any receiver mass -marketed in mass -marketed in the U.S.A. schematics, voltages, alignment, the U.S.A. The Photofact-n An- $3.95 each. parts lists, crystal formula data, nual Index lists the equipment pictorial presentations, and gen- covered in each volume. eral troubleshooting information. $3.25 each. No. 06557 $4.95

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Circle 21 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 73

www.americanradiohistory.com CIE graduate builds two -way radio service business into $1 ,000,000 electronics company!

How about YOU? Growth of two -way transmitters creates demand for new servicemen, field and system Edward J. Dulaney, Scottsbluff, Nebraska, (above and at right) troubleshooters. Licensed experts earned his CIE Diploma in 1961, got his FCC License and moved from TV repairman to lab technician to radio station Chief Engineer. He then founded his own two -way radio business. can make big money. Be your own Now, Mr. Dulaney is also President of D & A Manufacturing, Inc., a $1,000,000 company building and distributing two -way boss, build your own company. And radio equipment of his own design. Several of his 25 employees are taking CIE courses. He says: "While studying with CIE, I learned the electronics theories that made my present you don't need a college education. business possible."

Two -way radio is booming. There are already nearly Be Your Own Boss seven million two -way transmitters for police cars, fire There are other advantages, too. You can become your department vehicles, taxis, trucks, boats, planes, etc., own boss - work entirely by yourself or gradually build and Citizens Band uses. And the number keeps growing your own fully staffed service company. Of course, we by the thousands every month. Who is going to service can't promise that you will be as successful as Ed them? You can - if you've got the know -how! Dulaney, or guarantee that you'll establish a successful two -way radio business of your own, but the opportuni- Why You'll Earn Top Pay ties for success are available to qualified, licensed men One reason is that the United States Government doesn't in this expanding field. permit anyone to service two-way radio systems unless he's licensed by the FCC (Federal Communications How To Get Started Commission) . How do you break in? This is probably the best way: Another reason is that when two -way radio men are 1. Without quitting your present job, learn enough about needed, they're really needed! A two -way radio user electronics fundamentals to pass the Government must keep those transmitters operating at all times. And, FCC exam and get your Commercial FCC License. they must have their frequency modulation and plate power input checked at regular intervals by licensed 2. Then get a job in a two -way radio service shop and personnel to meet FCC requirements. "learn the ropes" of the business. As a licensed man, working by the hour, you would 3. As soon as you've earned a reputation as an expert, usually charge at least $5.00 per hour, $7.50 on eve- there are several ways you can go. You can move nings and Sundays, plus travel expenses. out and start signing up and servicing your own cus- Or you could set up a regular monthly retainer fee tomers. You might become a franchised service repre- with each customer. Your fixed charge might be $20 a sentative of a big manufacturer and then start getting month for the base station and $7.50 for each mobile into two-way radio sales. station. Studies show that one man can easily maintain Cleveland Institute of Electronics has been successfully at least 135 stations - averaging 15 base stations with 120 teaching Electronics for over 37 years. Right at home, in mobiles! This would add up to at least $12,000 a ygrar. your spare time, you learn Electronics step by step.

74 RADIO-ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com CIE's AUTO -PROGRAMMED® Lessons remove the APPROVED UNDER G. L BILL roadblocks by using simple, concise examples. You learn All CIE career courses are approved for educational in small, compact steps - each one building on the other! benefits under the G.I. Bill. If you are a Veteran or in You'll learn not only the fundamentals that apply to service now, check box for G.I. Bill information. all electronics design and servicing, but also the specific procedures for installing, troubleshooting, and maintain- r ing two -way mobile equipment. Cleveland Institute You Get Your FCC License ... of Electronics, Inc. or Your Money Back! CIEC I 44114 By the time you've finished your CIE course, you'll be 177E East 17th Street. Cleveland. Ohio Accredited Member National Home Study Council able to pass the FCC License exam. A recent survey of 787 CIE graduates reveals that better than 9 out of 10 Pease send me your two FREE books: CIE grads passed the FCC License exam. That's why I. Your book on "How To Get A Commercial FCC License." 2. Your school catalog, "Succeed in Electronics." we can offer our famous Money -Back Warranty: when complete licensing course, you'll be able to I am especially interested in: you any CIE Electronics Technology Electronic Communications pass your FCC exam or be entitled to a full refund of all Broadcast Engineering Industrial Electronics tuition paid. This warranty is valid during the completion First Class FCC License Electronics Engineering time allowed for your course. You get your FCC License Electronics Technology with Laboratory - or your money back! Name It's Up To You (Please Print) Address Mail the reply card for two FREE books, "Succeed in Electronics" and "How To Get A Commercial FCC Oty License." For your convenience, we will try to have a representative call. If card has been removed, mail cou- State -- - Zip Age pon or write: Cleveland Institute of Electronics, Inc., Veterans & Servicemen: Check here for G. I. Bill information 1776 E. 17th St., Cleveland, Ohio 44114. RE -13

Circle 22 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 77

www.americanradiohistory.com SERVICE CLINIC 4.5 MHz TRAP & (continued from page 72) SOUND VIDEO TAKE I9ZP4 PI X AMPL -OFF glect any of them. You can jar it, you TO SOUND 33 pF 1 .s,4# I.F. AMPL can change the supply voltage, or you all can heat it or cool it. Somewhere in II this list, you should be able to find 47K something will that make it show up. 12K 150K When you do, you've practically got it 680 BRIGHTNESS licked. R -E µH 300K 25K 5.1K CONTRAST reader 7W SHORTED

268V 135V questions VERT 15K BLANKING INPUT .015 BLACKOUT EXPLANATION 1KV In this column in the October is- IIHORIZ BLANKING sue Jim Franks told us about a G -E 6CÚ5 7 that did not display a raster until the AUDIO OUTPUT audio output tube was pulled. The basic trouble was due to a shorted .01- µF capacitor on the blanking network. The accompanying diagram did not include the audio output circuit and the connection between the blackout 135 VOLT and the audio circuit was not immedi- SOURCE ately obvious. This TV receiver used a stacked B + supply with the cathode of the audio output tube serving as the 135 - (continued on page 80)

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Circle 23 on reader service card 78 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com if you go for four channel...

you don't have to go for broke

Buy yourself a miracle for as little as $214.95 That's all The QS500 features three balance controls for front -rear it takes to get your conventional two -channel stereo to do and left- right, separate positions for decoding and synthesiz- anything any total four -channel receiver and control center ing, two -channel and four -channel tape monitors, electrical can do, now or in the future. rotation of speaker output, alternate -pair speaker selection, The Sansui QS500 and QS100 converters are complete and four VU meters. Total IHF power for the rear speakers Four -Channel Synthesizer- Decoder-Rear -Amplifier -and- is 120 watts (continuous power per channel is 4C watts at Control -Center combinations that transform standard two - 4 ohms, 33 watts at 8 ohms), with TH or IM distortion below channel stereo totally. The only other equipment you need 0.5% over a power bandwidth of 20 to 40,000 Hz. In its own is another pair of speakers. walnut cabinet, the QS500 sells for $289.95 You can decode any compatibly matrixed four-channel broadcasts or recordings and reproduce them in four authentic channels. You can detect the ambient signals An alternate four- channel miracle -maker is the modest present in most two- channel recordings or broadcasts and but well- endowed QS100, with total IHF music power of 50 propagate them through the rear channels. In Sansui matrix - watts (continuous power per channel of 18 watts at 4 ohms ing, the exclusive phase -shift technique prevents the can- and 15 watts at 8 ohms). In a walnut cabinet, it sells for cellation of some signals and the change in location of $214.95 others that occur in many matrixing systems. And the exclusive phase modulators restore the effect of the live sound field. You can plug in a four -channel reel -to -reel or cartridge deck or any other discrete source. In the future - if you should have to - you can add any adaptor, decoder or what - have -you for any four -channel system for disc or broadcast that anyone's even hinted at. And a full complement of streamlined controls lets you select any function or make any adjustment quickly and positively.

SANSUI ELECTRONICS CORP. 'Noocside. New York 11ál7 Gardera, California 90274 SGrrn cvi ELECTRONIC DISTRIBU -ORS (Canada), Vancouver 9, B.C. 4 COYIOM\ r YH9uo SANSUI ELECTRIC CO., LTD., Tokyo. Japan Sansui Audio Europe S. A., Antwerp, Belgium Circle 14 on reader service card FEBRUARY 1973 RADIO- ELECTRONICS 79

www.americanradiohistory.com READER QUESTIONS ages -now available from the 268 -volt fine, 9 ohms just as in the book. Tube (continued from page 78) line through interconnecting resistor good; do voltages all good. With networks -are such that the picture scope, no signal of any kind at any tube is biased on so the raster returns. point in oscillator circuit. volt B + source supplying. among Check all capacitors and resistors; other circuits, the cathode and grid of VERY THIN HORIZONTAL LINE they're good too. Now, try some of the picture tube (see diagram). 1 his one happened to me, and it the clever little tests you keep telling Normally, the cathode is biased at illustrates how reasoning intelligence other people to do, Darr. Clip lead to a fixed value of 120 to 130 volts and (and a good deal of luck) will help. heater voltage at a 6 -volt point. Feed the control grid bias varies from 0 to (A -Hem') There was nothing but a this to grid of lOGK6 output section. 135 volts with the setting of the very thin horizontal line on the screen Ilmmm. Nothing. Still very thin line. brightness control. When C209 of this Zenith portable: only one scan- Try higher voltage. 35 volts ac on shorted, it pulled the control -grid bias ning line thick, really. grid, still nothing on screen. Up scope. away down so the picture tube was Applying the standard tests. I Signal reads 35 volts (rms) on grid. cut off. Pulling the audio output re- pulled the yoke, and read the resis- On plate, about 2 volts peak -to -peak, moved + 135 volts as a source of bias tance; fine. Resistance of yoke section at the most. for the picture tube. The bias volt- of vertical output transformer also Well! Recheck dc voltages on output section just for luck. All present and accounted for. Now what's going on? Sit back and try something brand- new -THINK! What could cause an amplifier tube, with plenty of signal on its grid, to have

oyir f6,u!! "; absolutely zero gain? One thing -a load impedance of absolutely zero ohms. Pick up ohmmeter, turn set off, read resistance of îJA primary section of vertical output transformer. Is it 275 ohms, as it says on the schematic? It is not! It is just AUDIO TEST INSTRUMENTS what you thought; absolutely zero. Replace transformer, everything lovely. (This was apparently a lead - You Can short, from the very low resistance. It Now Say was in warranty, so I replaced it) MORAL There is always a legitimate. theo- Service... and Smile! retically correct cause for everything, if you can just find it. R -E

LV -77 LFM - 30 FET MULTIMETER TAPE SPEED /CHECKER EQUIPMENT REPORT Solid state dependability Checks any tape recorder and staodity plus high im- for speed and drift accura- (continued fron page 32) pedance -make this a fine cy at 3KH7 as well as 1. 2, 4, general purpose meter. Has 5. 6, 7 8 8 9KHz frequencies. dual power supply -bat- 1OiiMV to 10Vrms input teries and AC line. It's level. o5% end scale ac- reverse side of the chart shows a com- truly portable! t3% full curacy with -3% to .3% test scale accuracy with easy to range. Complete with plete system hookup clearly dia- read. clearly marked carrying case. gramming all rear panel receiver con- face $ 129.95 .4P S panel. $109.95 nections. Internal construction is on a number of printed circuit boards most of LSW - 250 which have connectors for easy re- FM -TV SWEEP /MARKER [On- GENERATOR moval for repair or replacement. Use with any scope to test and kyo's attention to detail is completed service FM. TV and more Has 2-260MHz freq. range, cont. ad- by the inclusion of an assortment of justable. with calibrated markings phono plugs and speaker and line for most often used bands. Mark- ing method is post infection with fuses along with a polishing cloth for external signal input provision. Highly stable and accurate. the nicely veneered standard cabinet.] With accessories. $309.95 After having seen and operated many stereo receivers in the past we LMV- 89 are always suspicious of a new in- 2 CHAN. AC strument. We try not to be misled by MILLIVOLT METER Test stereo circuitry and 4-channel good looking mechanical construction too--especially where differences and reserve our opinions until the exist in voltage at two separate points. t3% full scale accuracy equipment has been used for a few 11KHz); dB scale readings at OdB=0.775V and 1V each. 2 chans, days and we are completely familiar 100MV to 300V range in 12 steps. with it. We were delighted with the With separate pointers, individual switches. and amplifier systems. TX -666 and the way it did not let us Both channels operate separately or together. down. Take a good look at this one $229.95 before making a final choice. Ware lot details See your distributor. The TX-666 weighs 28 pounds The more you see ... the more you believe ... the more you save and measures 18?'s" wide by 15' /a" Leader Instruments Corp. 37 -27 Twenty -Seventh St. L.I.C.. N.Y. 11101 (212)729 -7410 deep by 51/2" high. R -E Circle 25 on reader service card 80 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com Our ECG 102A transistor replaces...

NI fix ReplACet1 io Be Scia Replaced RNtioce'pefri :l1 O2.P. n!t .' 1 O2 P. INA F\a'.'.4. . 1p2A MÁ3.1 i ; 0 7 1 1 A MAFi 1 A M<\f3fi 1 07 n /1/\ S14 .. 1 C) 'l A N 1AF.3fR.+. 1 02 /\ t-4 -1 102A 1 A 02 A M A $ F3 (', 1 02 M"8t3 7 102A NIA8i3f3 11p2A 02 A NIA88',f 102A MA891!VI AH30 102P MA892 , 02 A MA893 1 02 A MA895MA$94 102A MA89E3 1 0 2

and hundreds more.

The 102A is only one big part of No more lugging sets back to the our very small line. shop because you couldn't carry all Just 124 Sylvania ECG semicon- the parts you needed. ductor parts will replace over 41,000 With Sylvania's 124 semiconduc- manufacturer's part numbers and tors you can handle almost all of JEDEC types. your repair jobs right in your cus- Our new ECG semiconductor re- tomer's home. placement guide makes it easy for Stock up on Sylvania ECG semi- you to find out exactly which one of conductors now. ours is the one you need. It's just another small thing from With our guide and our 124 re- GTE Sylvania that can take a big placements, you can service prac- load off your back. tically any solid -state entertainment Sylvania Electronic Components, product on the market. Waltham, Mass. 02154 an SYLVANIA

www.americanradiohistory.com new products

tegiated circuits and operates from 12 More information on new products is available from the volts dc. Output impedente for the matched 4- speaker system is 8 ohms. manufacturers of items identified by a Reader Service num- 75,8" x 3'ie" x 7 "; 8.8 lbs.- Audiovox Corporation, 150 Marcus Blvd., Haup- ber. Use the Reader Service Card inside the back cover. pauge. N.Y. 11787. Circle 33 on reader service card AUTOMATIC TURNTABLE, 42M Pre - with walnut- finished vinyl trim. Following Pack includes choice of Shure or Pick- the simple step -by -step assembly man- CASSETTE TAPES, Professional series ering magnetic cartridge with elliptical ual, the electronic digital clock can be 261 uses wide -range full -fidelity tape. stylus. Three -speed unit comes with assembled in two evenings; no knowl- Torque -control liners are made of graph- base. Selected cartridge is premounted edge of electronics is necessary. $54.99 ite coated polyester and the case is and accurately balanced in the pickup plus shipping. -Heath Company, Benton high- impact plastic with sealer windows. arm. Harbor, Mich. 4022. Tape guide system has lubricated stain- The turntable has a gimballed, low- Circle 100 on reader service card

CB TRANSCEIVER, Prestige 2300 has easy -to -read dial indicator for quick channel identification. An accessory plug is provided for remote operation. In addition to operating in the AM mode for all 23 channels, the model may be used to monitor any of the 46 SSB channels in the Class D frequency. Works on 12 volts dc. Model P5804A

mass aluminum arm with a fixed counterweight balanced for the particu- less steel pins with rotating guide rollers. lar cartridge in the unit. A damped Packed in unbreakable plastic al- cueing and adjustable anti -skating de- bums, prices are $1.80, $1.85, $2.90 and vice are also featured. $90.85. -Gar- $3.45 for 40 -, 60 -, 90- and 120 -minute rard, Div. British Industries Company, tape cassettes. -Irish Magnetic Tape, South Service Road, Westbury, N.Y. regulated power supply provides for easy 270 -278 Newton Road, Plainview, N.Y. 11590. conversion to base operation. A locking 11803. Circle 31 on reader service card mobile mount and plug -in high- imped- Circle 34 on reader service card ance ceramic microphone are included. DIGITAL ELECTRONIC CLOCK KIT, GC- Remote speaker and public address fea- BREADBOARD AID, Digi Designer incor- 1005 employs solid -state digital circuitry tures are also provided. -Pace Commu- porates the SK -10 component socket, a with illuminated readouts for hours, min- nications, Pathcom, Inc., P.O Box 306, variable, six position 1 to 100 kHz clock, utes and seconds. The electronics is Harbor City, Calif. 90710. four logic lamps, four switches, two contained in one large -scale integrated Circle 32 on reader service card bounce -free pushbuttons for use as circuit. Secondary solid -state circuits pulsers and an internal 5 -volt dc power drive the cold- cathode readout tubes CAR STEREO TAPE PLAYER, C976 is a supply. There are numerous terminal and make up the power supply section theft-proof 8 -track AM -FM -FM MPX car stereo tape player that is easily and pro- fessionally installed into the dash. It features: five pushbutton AM/FM tuning, 8 watts output per channel on

which can be pre -wired to accept either 120 or 240 Vac. A 24 -hour "beeper" alarm with seven -minute "snooze" button is in- FM and tape, local /distant switch, vol- points on the front panel for external included. The clock can be wired to dis- ume and tone controls, front -to -rear and puts or patch cords. play conventional or 24 -hour inter- left -to -right balance control and auto- The model enables the user to com- national time. Alarm and time settings matic and manual track switching. pletely design and test a circuit by are made with hold- and-run switches in The unit has a solid -state chassis merely plugging his components into the the clock base. Cabinet is black Cycolac with 18 transistors, 12 diodes and 4 in- SK -10 socket and interconnecting with 82 RADIO-ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com standard No. 24 AWG hook -up wire. No The spring -loaded gripping surfaces will manently tools, test equipment, TV's and soldering necessary. not slip, yet have a smooth finish to pre - radios. Available in kit form $49.95 or wired vent scratching fine wires. An insulating $19.95 with set of standard steel $95.06. -EL Instruments, Inc.. 61 First cushion grip permits burn -free handling. points, carbide point $2.95 additional, Street, Derby, Conn. 06418. 3 % ", weighs '/z ounce. $2.40. -Xce- diamond point $7.95 additional. -Electro Circle .35 an reader service card lite, Inc., Orchard Park, N.Y. 14127. Stylus, 31 Cheyenne Blvd., Colorado Circle 36 an reader service card Springs, Colo. 80906. HEAT SINK, NO. 80 is used for absorp- Circle 37 on reader service card tion and dissipation of heat in soldering MARKING AND ETCHING IN- operations where adjacent, delicate elec- STRUMENT, Mark VII Electro Stylus is INDOOR SPLITTERS & MATCHING precision made, rugged, dependable and TRANSFORMERS, models 3021 and easily handled. Weighs 7 ounces and is 3022 are two -way splitters; models 3031 and 3032 are three -way devices and

tronic parts might be damaged by overheating. 34' in diameter- It plugs into any ac out- 3041 and 3042 are four -way types. All The copper jaws have nickel -plated let. Noise level is very low. have an output impedance of 75 ohms at surfaces to prevent adhesion of solder. Electro Stylus is used to mark per- all ports and operate over a bandwidth

It's time to order your 1973 RCA Solid State Databooks Complete, up -to- the -minute data for RCA's IC's and discrete devices.

Get off to a fast start in 1973 with timely comprehensive data from RCA, the company that specializes in complete, accurate data on all of its solid state devices. The 1972 DATABOOKS have been used in thousands of plants in the United States and around the world. And even more plants will be reached in 1973. This is your chance to be one of the new recipients. The new DATABOOKS cover a great range of your requirements because RCA has some of the broadest lines in the industry: linear and COS /MOS ICs, MOS -FETs, power transistors, power hybrids, RF and microwave devices, thyristors, rectifiers, and diacs. 25% new or revised material. Complete commercial product data. Complete, current application notes. Easier -to -use quick- reference guides. New, comprehensive subject index. Cross -reference index of developmental to commercial type numbers. Six 1973 DATABOOKS for only $12 (optional list price), with monthly new products newsletter. See coupon for details. Send the coupon along with your check or money order (payable to RCA Corporation) or your company purchase order. Or call your RCA distributor. If the coupon is missing, write RCA, Solid State Division, Section 132B, Box 3200, Somerville, N. J. 08876.

RCA Corporation Solid State Division Section 132B, Box 3200 Somerville, New Jersey 08876

Rush me the six 1973 DATABOOKS and put my name on newsletter mailing list. My cost. only $12. Rush me prices for individual DATABOOKS and updating service.

NAME /TITLE

COMPANY

ADDRESS

CITY /STATE /ZIP

I enclose payment by: Check Money Order Purchase Order Offer good only in U.S. and Canada. Direct other inquiries to RCA sales offices or distributors.

Circle 6/ on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 83

www.americanradiohistory.com of 5 to 300 MHz. one continuous and automatic cycle. Re- The transformers, models 3000 and production of the play -back cassette of- 3002, also operate over the same band- fers outstanding sound quality with sig- width and are similarly rated except for nal -to -noise ratios of 35 -40 dB. mechanical configurations. -GTE Syl- 8'/2 x 8Y2 x 5 inches, molded in vania, Inc., 730 Third Avenue, New York, N.Y. 10017. Circle 38 on reader service card

METAL CUTTING SNIPS. A new line of aviation snips, metal snips and light metal and wire cutting snips are spe- cially designed to yield maximum cutting power with minimum effort. Blades are scientifically heat -treated to assure uniform hardness, machine hollow ground

scuff-proof plastic with grey finish. $325.- Dictaphone Corporation, 120 Old SERVICEMASTER Post Road, Rye, N.Y. 10580. Circle 41 on reader service card

POCKET CALCULATOR KIT, AR -420K is provides all full four- function electronic calculation using an MOS /LSI integrated circuit. Entries are quickly made on a your best buy compact elastomar keyboard and answers are displayed in floating -point for- to provide long -lasting cutting edges and mat on eight bright LED displays. individually fitted to give uniform cutting Chain features allow for long, mul- in domestic action, Handles on all styles are equipped with dipped heavy vinyl, hand - ease cushion grips. -Channellock, Inc., and Meadville, Pa. 16335. Circle 39 on reader service card

AUTOMATIC DIALER, Name Caller. New foreign low -cost telephone dialer. Works on home and business telephones. You install it yourself, program up to 38 names tubes. with special pencil supplied with each

Discounted to provide you with a higher profit margin. tiple-step calculations. A constant- regis- ter makes multiple powers, conversions, Proven quality for better customer reciprocals and (indirect) square roots satisfaction. easy to obtain. 91/2 ounces, $75 with batteries. - Arles, Inc., 119 Foster Street, Peabody, A complete range of domestic and Mass. 01960. Circle 42 on reader service card foreign service types for consumer unit. Home model $49.95; business ALARM SYSTEM, SS -200 is a complete and industrial electronics. model $59.95. -Video Systems, Inc., self- contained ready -to- install solid -state 12530 Beatrice Street, Los Angeles, Ca- closed- circuit burglar alarm system. lif. 90066. Opening any door or window, cutting the For complete details, contact your Inter- Circle 40 on reader service card alarm wires or tampering with the cabi- national representative today, or International net sounds the alarm. A 25 -30- second ANSWERING SYSTEM, Ansatone time delay eliminates the need for an Components, 10 Daniel Street, Farmingdale, 640 can be programmed in advance to set on /off entrance door key switch and al- New York 11735/(516) 293 -1500. the time allowed for incoming messages. lows you sufficient time to shut the alarm The outgoing message cartridge is off upon entering the apartment. plugged inside the unit. The user lifts the System includes: tamperproof SERVICEMASTER hinged cover, plugs in the cartridge, weather- resistant steel cabinet with fl- connects a small hand -held microphone inch alarm bell; front and rear tamper and records the outgoing message. switches; solid -state control module with International C The incoming message controls are time delay; electrical switch lock with within easy reach and include an on -off two keys; three pairs of closed- circuit International Components Corp. and volume switch. When a call comes window contacts; exit door contact Div. of IESC in, it is automatically answered, the mes- (N.O.); interior on /off switch; sage given and the recording begun in panic /battery test switch; warning de- Circle 62 on reader service card 84 RADIO- ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com cals; 100 feet of hook -up wire; installa- lated floating ground, rugged heavy - windings on the flyback transformer. It tion instructions; operates on standard gauge aluminum case, tinted viewing starts instantly, operates cool and reduces X- radiation. Peak inverse voltage is 45 kV, peak repetitive forward current, 5 mA, average forward current, 5 mA and voltage drop is 50 volts at 5 mA.- Electronic Devices, Inc., 21 Gray Oaks Avenue, Yonkers, N.Y. 10510. Circle 44 on reader service card

12 -volt lantern battery (not supplied); $74.95. -EICO Electronic Instrument Co., window and universal banana jacks. Inc. 283 Malta Street, Brooklyn, N.Y. $79.95. -Heath Company, Benton Har- 11207. bor, Mich. 49022. Circle 43 on reader service card Circle 100 on reader service card

DIGITAL MULTIMETER KIT, 1M -1202 can SOLID-TUBE, R-3AT2 is the solid -state be assembled in two or three evenings. high -voltage rectifier that replaces 3AT2, A 21/2-digit cold- cathode readout ends 3AW2, 3BL2, 3BM2 and 3BN2 vacuum parallax and interpolation errors. Accu- tubes. racy is within 1% on dc volts, 11/2% on ac volts and alternating and direct cur- birth defects rent, 2% on ohms. 29 selectable ranges measure voltages from 10 mV to 1000 V are forever... on dc, either polarity; 10 mV to 700 V unless you help rms on ac; 10 ,uA to 2 A on ac or do and

1 ohm to 2 megohms on resistance. Features include: three -wire line cord, dual -primary power transformer, Operating without a filament, the R- overload protection on all ranges, iso- 3AT2 eliminates the need for filament THIS SPACE CC,NTH BUTEU By THE PUBL!SHEP

NEA NATESA MEMBERSHIP PROGRAM

NEA -- 1309 West Market St. -- ITTA Bldg., Indianapolis, Ind. 46222

NATESA -- 5908 South Troy Street, Chicago, Ill. 60629

Service Dealer ..,, o 3rN1 1311i.,, Address ICr ocrCtN1 tn 3111nÌÚP 3 31.CL1 iww 0J6 `` uiB Mr al City State Zip 1 (OVID ,,,,,,jl,,,,,1 Per

All New Members must be signed up and approved by either NEA, or NATESA. (First Year dues paid -- $35.00). (Dual * NEW Membership not acceptable).

EACH approved NEW NEA or NATESA Member will receive "gifts" digital VO. M. $299 from sponsors listed below in excess of $40.00 (Retail Sel- 100 ling Price). 26 ranges to measure ac /dc voltages from microvolts to 1200 V, ac /dc currents from 100 nanoamperes to 2 am- NEA and NATESA shall have the sole jurisdiction as to the peres and resistance from 100 milliohms to 20 megohms. pro- rating of "Gift Certificates" to their respective Dis- Basic dc accuracy, 0.1 %. Guaranteed for one full year. trict, States or specific areas. Their decision shall be Fluke gives you the best specs and strongest warranty on the final. market today for the lowest cost of ownership ever. Wide choice of options including rechargeable battery pack, digi- We are very grateful to the Sponsors of this program and tal deluxe test leads, high -voltage probe, RF suggest our theme, "Support Your Supporters" be carried printer output, out. probe, 200 -amp ac current probe, carrying case, dust cover and rack mounts. Unique self -zero feature eliminates off- SPONSORS: set errors. Rugged high- impact case with securely mounted internal electronics. Service centers throughout U.S., Can- AMPEREX ELECTRONIC CORP. ada, Europe and Far East for 48 -hour turnaround r3pairs. TECH SPRAY THE FINNEY CO. P.O. Box 7428, ELECTRONIC DEVICES INC. Seattle, Washington 98133. INTERNATIONAL RECTIFIER FLUKE For further information as to how you can take advantage of this amazing offer, fill out and send the coupon to either Get all the details from your nearest Fluke sales office. Dial NEA or NATESA. (Check preference) toll -free 800 -426 -0361 for address of office nearest you. MEMBERSHIP DRIVE ends March 31, 1973. Circle 63 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 85

www.americanradiohistory.com Whatever new literature your tape handling All booklets, catalogs, charts. data sheets and other literature needy listed here with a Reader Service number are free. Use tho Reader Service Card inside the back cover.

PRINTED CIRCUIT BOARDS CATALOG, 12 player service he requires. -PTS Electronics, pages of new sensitized printed circuit boards Inc., P.O. Box 272, 5233 Hwy. 37 S., in this company's line of breadboard and Bloomington, Ind. 47401. printed circuit supplies. The catalog also gives Circle 50 on reader service card information on chemicals used in electronic servicing and maintenance. -Injectorall Elec- TOOLS CATALOG 1973 Edition. A 64-page tronics Corp., 98-100 Glen St., Glen Cove, catalog of high -quality, professional tools and N.Y. 11542. other products. The collection includes hard - Circle 45 on reader service card to -find hand tools and small power tools used extensively by technicians, designers and ser- TECHNICAL BOOKS 1972-1973 Edition. 28- vice personnel. Many items listed in the cata- page catalog describes more than 235 current log are rarely sold by industrial distributors or and forthcoming books plus ten new elec- commonly found in stores. -Brookstone Co., tronic book /kits. Books listed in the catalog Peterborough, N.H. 03458. cover amateur radio, appliance repair, audio & Circle 51 on reader service card hi -fi, basic technology, computer technology, electronic book /kits, electric motors, engineer- Write direct to the manufacturers for infor- ing & reference, general electronics servicing, mation on items listed below: hobby & experiment, license study guides, test cassette & and equipment, transistors semiconductors STEREOSCOPIC TELEVISION. A new techni- TV schematic /servicing manuals -Tab Books, cal paper presented recently at a technical Blue Ridge Summit, Pa. 17214. symposium. This paper surveys a number of a Circle 46 on reader service card 3- dimensional television systems and describes in particular the Stereotronics System ELECTRONIC KITS 1973 catalog. All kinds of which optically converts normally flat closed - electronic project kits including color TV's, au- circuit television into 3 -D TV.- Stereotronics dio equipment, marine gear, amateur radio Television Co., 13720 Riverside Drive, Sher- equipment, automotive electronics, electronic man Oaks, Calif. 91408. organs, electronic clock, electronic calculators, security systems and a complete range TRANSISTOR SUBSTITUTION GUIDE catalog of electronic test equipment. Complete de- 276 -2000. This guide lists 15,000 commercial scriptions of the kits and the specifications of transistor types which in most cases may be the completed equipment are included in this directly replaced or substituted for with one of cartridge 80 -page catalog. -Heath Company, Benton 29 Archer transistors. Detailed specifications Harbor, Mich. 49022. and electrical characteristics for each of the Circle 47 on reader service card 29 transistors are given in the booklet. 24 of them are custom made for Radio Shack by EXPERIMENTER'S CATALOG No. 731 con- Texas Instruments and five are imported. The tains more than 4.500 unusual bargains for ex- 96 -page book also contains data on the care perimenters and hobbyists. This 164 -page and handling of transistors, details on testing catalog lists items in almost every area of in- transistors and important suggestions on the terest from astronomy to weather instruments. use and replacement of transistors. The guide Along the way are all kinds of electronic gear is priced at $1.00. -Radio Shack, 2617 West as well as items to fit the needs of associated Seventh Street, Fort Worth, Tex. 76107. R -E hobby interests. While this is a catalog, it is most certainly also an interesting book to read.- Edmund Scientific Co., 700 Edscorp Bldg., Barrington, N.J. 08007. reel to reel Circle 48 on reader service card FRONT PANEL COMPONENTS condensed Telex has an answer. Professional mag- catalog CC -72 -8. 12 -page listing of miniature netic tape handling equipment, designed switches, toggles, push buttons, printed circuit for heavy duty commercial and industrial types, etc.; high -quality aluminum and plastic use. Available with a wide choice of knobs; isolation relays combining relay trans- configurations, options and associated former and contacts in one small package; electronics. Write for free information. neon and incandescent 7- segment single - plane readouts, lamps and indicator assemblies; and ceramic terminal strips. -Alco Elec- PRODUCTS OF SOUND RESEARCH tronic Products, Inc., 1551 Osgood Street, North Andover, Mass. 01845. Circle 49 on reader service card TELEX® PTS EXPANDS FACILITIES. Bloomington, In- diana facilities have been doubled in size. The COMMUNICATIONS D I V I S I O N new plant includes provisions for repairing 8- 9600 ALDRICH AVENUE SOUTH MINNEAPOLIS, MINNESOTA 55420 track and cassette players in addition to the usual TV tuner repair facilities. More than 60 "When to CANADA. DOUBLE DIAMOND ELECTRONICS. LTD 01118110 trained technicians at six PTS locations give you're finished, I'd like you EUROPE ROYAL SOUND COMPANY, INC , 409 North Mein 51., Freeport, N.Y 11520 U S A INTL TELEX EXPORT DEPT., 9800 Aldrich Are S. Minneapolis. MN 55420 U S A the electronic technician the tuner and tape take a look at my husband" Circle 64 on reader service card 86 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com LETTERS The beauty that was once this (continued from page 24) natural country...

America is suffering from pollution. But doesn't nal quality, and it is in these areas that have to be. That's the tragedy. America can again be as as it once was. If we all get involved. matrixing just doesn't make it. beautiful Involved with things like putting trash in proper Discrete will give us these things, receptacles. Or carrying a litterbag in our cars. but at present will also limit the dynamic Let's restore the beauty that was once this country. and frequency ranges. So let's just con- centrate on our 2- channel systems (ex- People start pollution. cept with tape) and wait for the day People can stop it. when RCA announces that it has available those top two octaves and 30 dB more dynamic range (with Dolby C ?). With the present speed of development Cou NG`y© in electronics, it shouldn't be longer than m`; advertising contributed Keep America Beautiful for the public good a couple years. MICHAEL SABLOSKY, USIS -AM. EMB., APO San Francisco

ABOUT STRIPES OF ANOTHER COLOR Some Stupid -)(' + / %8 %#@ -Put In The Wrong Resistor -or -The Case Of How To Solve A Color Problem By Mak- ing It Worse. Some time ago, the problem of how to see a brown color stripe on a brown resistor was brought to the attention of resistor manufacturers. The resistor manufacturers responded with great haste (since they desire in every way to please all their customers). However, the response has proven to be too much -too soon. The result - .the brown color code paint was made The World's Largest more red, in fact, some brown color stripes are now red. Consumer Electronics Catalog

. . . watch for So out that brown The world's Foremost consumer electronics color stripe. If the schematic shows a catalog is yours for the asking! Over 25,000 680 -ohm resistor and the third color items . . . jampacked with illustrations and stripe on the resistor looks red, don't be descriptions of the very latest in Hi -Fi, CB, too sure the resistor is the wrong value - Tape recorders. Radios, Television, Elec- measure it. The rule to follow now is Parts, Publications. don't trust your eyes to see a brown tronic Technical color stripe on a resistor. That orange or red stripe could be the new industry Shade of Brown. Everything in Electronics For Home, Business, GTE SYLVANIA SERVICE BULLETIN Industry PLUS The Latest in 4- Channel Stereo!

LAFAYETTE 1973 CATALOG 730

Our 52nd Year Stores From Coast -to -Coast

MAIL LAFAYETTE RADIO ELECTRONICS THE P.O. Box 10, Dept. 17023 "OPEN -AIRE" HEADPHONES have all the COUPON Syosset, L.I., N.Y. 11791 makings of a perfect gift: professional TODAY quality and reasonable price. New design Send For Your Free Lafayette Catalog Today! principle combines unusually light (5 oz.) 1 rSend me the FREE LAFAYETTE Catalog 17023 weight, wide (20- 20,000 Hz) response Name . . . all the realism of stereo without cumbersome size and uncomfortable ear Address _ seals. Give a gift of privacy and perfect State Zip sound. Only $39.95 from Sennheiser Elec- City tronic, 10 W. 39 St., N.Y.C. 10018. ® .14 i Circle 95 on reader service curd Circle 69 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 89

www.americanradiohistory.com Need high temperatures in tiny places? The amazing Little Torch is so tiny hydrogen, propane, natural gas or a of °F. this it can throw flame 6300 Mapp. It's available with five tips try through the eye of a needle. It sol- ranging in size from one large ders, brazes, welds and heats with enough to weld 16 ga. steel to one exacting precision in the smallest small enough to weld .002" copper places; uses oxygen and acetylene, wire. For free brochure write to:

LOUPE AIDS METER READINGS A jeweler's loupe is a handy de- Instrument vice for increasing visual resolution when reading small movements of meter pointers. It is especially useful when sensitive meters are not readily available. It can be used when measuring a true or a relative value. To illustrate, you want to see if a particular circuit action causes an in-

JEWELER'S LOUPE

VOM OR VTVM

MAGNIFIED READING

crease or decrease (a very small change) in the meter reading. Use the correct meter scale if you are inter- Dept. SS -2, 2600 Niagara Lane No., Minneapolis, Minnesota 55441 ested in true values. For relative read- Circle 70 on reader service card ings, use the scale that has the greatest number of minor divisions. You can detect any change more easily as a The "Country Boys" Have it! numerical value (two divisions, three divisions, etc.). -Alex Billos

SIMPLEST "LIGHTS -ON" New Universal Type REMINDER I needed a headlight /parking COLOR TV YOKE light reminder for a new car so I searched back issues of Radio -Elee- tronics for a circuit. I found plenty of them -but each schematic specified REPLACES YOKES OF OVER one or more parts that I did not have 200 DIFFERENT MFR'S in stock. I decided to design my own INCLUDNG HITACHI, TOSHIBA AND NIVICO HORN RELAY

BUZZER

Oneida's OCY -95 Universal Color TV Yoke does it all. It's the hottest item in the marketplace ... being used in the BUZZER following: Admiral. Airline, Ambassador, TERMINAL AMC, Andrea, Arvin, Bradford, Catalina, Clairtone, Coronado. Curtis Mathes. DuMont. Electrohome, Emerson, Hitachi, Hoffman, Muntz. Nivico. Olympia. Packard -Bell, Penncrest, Philco -Ford, RCA, Sears Silvertone. Sylvania. Toshiba. Truetone, Westinghouse. Standard warranty. Complete schematic and all manufacturers' part nos. enclosed with each unit. and came up with the one shown. No See your local distributor. If he doesn't have it ask him to transistors, no diodes, no speakers - a for order supply you just a simple relay (12 volts dc, spst, normally open).

The " "Country Boys"' Appreciate Your Business The new car has a buzzer that sounds when you open the driver's MFG. INC. ONEIDA ELECTRONIC door without removing the ignition MEADVILLE, PA. 16335 key. We use it for the "lights -on" reminder. The sketch shows the hookup. -E.A. Orlowski. Circle 71 on reader service card 90 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com LOW COST KEYBOARDS The XR205 monolithic continued ./ton? page , Ai outstanding offer fcr the engireer, WAVEFORM shift, keys that shift, and the ability to ent or use "control" keys that do not enter a GENERATOR character but that tell things at the other end to start, stop, linefeed, car- KIT riage return, change mode. clear, etc. These are called transparent com- Only mands and you'll find out more on them in another article. $28.00 Somehow the keys have to be ar- Here's a highly versatile laboratory ranged to end up with all these func- instrument for waveform generation at a tions and still have a reasonable number of leads coming out of the fraction of the cost of conventional waveform or function generators. keyboard. If we bring everything out, The Kit contains: there would be 110 contacts and 110 1) Two XR205 waveform generator IC's wires. If we go to a common contact ) c. Flr 2) Data sheet and applications notes on each key, this drops to 56 contacts, 3) PC board (etched and drilled, ready for still a ridiculous number and worse assembly) Immediate Ce'ivery. yet. we'd find the encoder got more 4) Detailed assembly and hook -up complex in the bargain. To get around Order direct from: instructions with parts list, schematic and layout diagram. this, we arrange the keys in a pre-en - EEP CORPORATION coder matrix. This matrix is shown in EEP 10180 W. JEFFERSON BLVD. Fig. 9. It simply groups keys that are CLLVER C -.TY, CA. 90230 213/838 -1912

( i; < te 65 on reader .service card

I I

G'IVE... w ll Ì ve HEART FUND Contributed by the Publisher

I f

1 1 first time at this low price! I I ^II ALL-IN-ONE

I I

I .. VOM /TRANSISTOR

FIG. 9- PRE -ENCODER MATRIX groups the TESTER $4995 related keys to the encoding scheme. simplify MODEL HM-310 im related in the encoder together. You 100 Fßí /V Taut Band movement, end up with only 22 connections on MirroreC Scale the keyboard's output connector and Burn -Out Protectior still can use an extremely simple encoding scheme. The pre -encoder is de- Transistor Alpha & Beta signed specifically for the ASCII en- Transistor Ico coder to be described in another Measures Capacitance article. You wire the pre -encoder by Self -contained providing 100 jumpers as shown on Volts, Current, Reg. $5995 the top of the PC pattern; these can Measures AC /DC and Ohms 22 Ranges be quickly "sewn" into the board in it one continuous run: you then cut off r 1 OTHER QUALITY METERS . . . PLEASE SEND MODEL the unwanted jumpers you get on the I I back side, and the job ends up much Model HM -312 ENCLOSED IS $ full range VOM ._. $35.75 I simpler than it seems at first. SEND C.O.D. I Model HM-315 (Add for shipping and handling. Calif. add 5% tax) Should you want another code, Transistor /`Diode tester _.. $34.65 $2 FREE Data Sheet I you simply work up your own pre-en - Please send coder matrix by changing the jumpers. NAMF I The matrix has purposely been kept ADDRESS I this flexible so you can use this key- CITY I board in many systems without added 71 expense or unreasonable modi- hm electronics, inc. STATE P I 10975 SAN DIEGO MISSION ROAD Prices and specifications subject to change without notice l fications. 1f you are absolutely sure of SAN DIEGO, CALIFORNIA 52108 TELEPHONE: ( 7141 25O -6050 (turn page) Circle 66 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 87

www.americanradiohistory.com EQUIPMENT REPORT LOW COST KEYBOARDS (continued /roni page 26) (continued from page 87)

straightforward with the exception of the pattern you want, a double -sided the subtraction function. This opera- PC board may he used, but this tion is done the same as addition ex- freezes your design and ups the cost. \EW a is cept special equal sign reserved for Assembly of the big keyboard this purpose is used. This quirk soon pretty much the same as the smaller from becomes second nature. Entering a ones. Two blank keys are provided; number with too many digits lights they are ASCII encoded as "can" and the overange indicator as does a calcu- "em ". This lets you transparently pass endeco lated result outside of the - 99,999,999 two special commands on for the rest to +99,999,999 range. When this in- of your system without needing to dicator lights further calculations are press the CONTROL button. You can locked out since they would lead to make it do anything you like on the erroneous results. The keyboard other end. worked well with a sensitive touch de- The Pencil Soldering Iron spite the lack of tactile and audible PARTS LIST (12 -key keyboard) with Operating Light, feedback. 12 Keytops, two shot molded plastic, 0 -9, (.), Anyone purchasing the kit should and (t) 2 Heats and 1 seriously consider the charger /ac 12 Contact stems per Fig. & Fig. 2 1 2" x 2" contact pad material, carbon ure- On /Off Switch power option. Some of the com- thane sponge 1/4" thick. Cut into 0.4" square ponents for this option are added to keypads $10.95 Model 540S 1 2" x 2" damping pad material, 1 /16" soft NET Soldering Iron the clock /power supply hoard. rubber cut into a dozen ' /z" round damping Length 81/2" If you are an experienced kit Weight 2 oz. pads builder the Aries calculator kit will 1 Extension spring, 1/4" i.d. x 3" long x .016 Light shows when it's on give you a cache of arithmetic power music wire. Stretch to Fig. 2-e and cut every 9th turn, forming a dozen keysprings 2 heats -20w and 40w- that you can conveniently carry in 1Top panel per Fig. 3 and text 31/2" x 2'/8" x your jacket pocket with its 3 13/16 x for any job 1/16" fiberglass or other insulator 45/8 /4 Ironclad tips for longer life x l' inch dimensions. Sold by 1 Bottom panel, 1/16" plated PC material per Cool, unbreakable polycarbonate B & F Enterprises for $75 the recom- Fig. 3 and text 33/4" x 21/4" x 1 /16" handle mended charger /ac power option is 4 6 -32 x 35" threaded spacers 4 6 -32 x 1" machine screws $17.50 including the four nickel cad- Burn -resistant neoprene cord 4 6-32 nuts mium AA cells. R -E 4 No. 6 shakeproof washers to a iron Converts desoldering MISC: solder and rosin flux; optional adhesive; with low cost attachment template for contact stem assembly

The Pencil Desoldering Iron with Operating Light, PARTS LIST (55-key keyboard) 55 Keytops, two shot molded plastic, standard and On /Idle /Off ASCII characters and spacebar 57 Contact stems per Fig. 1 & Fig. 2 Switch 1 4" x 4" contact pad material; cut into 57 0.4" square contacts 1 4" x 4" damping pad material, cut into 57 $15.95 round damping pads NET 0.5" 4 Extension springs, cut into 57 springs after extending 1 Top panel, insulated PC material, 4" x 4" Model 510 I Length 8' /:" 1 Bottom panel, per Fig. 6; 63/4" x 14" Desoldering Iron Weight 31/2 oz. AC. 2 Support brackets, 14" long MISC: Threaded spacers, shrink tubing, and when it's on Light shows mounting hardware; No. 24 solid wire; sol- Operates at 40w; idles at 20w der; optional glue or epoxy; keystem solder- for longer tip life THE ing template. 6 tip sizes available ALL -CHAN to handle any job C.V.U. Cool, unbreakable polycarbonate Contact material Is available from Cus- tom Materials, Inc., 279 Billerica Rd., Chelms- handle the best antennas f ford, Mass. 01824. It's their *7611 Velofoam Burn- resistant neoprene cord In these fea drivenes and magnetically '/4" thick, and runs around 'hC per keytop, but log periodic retleclor Exclusive new bracket insures the corner is only available In large sheets. with an exclusive a arrays o Keytops are available from Mechanical alignment, prevents damage UHF section wave of it s Enterprises, 5249 Duke St., Arlington, Va. 15C magnetic unique to oure The each, any reasonable callout. Space bars are New kits also available! top performer. discriminate ability 35C each. $2 service charge on orders under Desoldering Kits is the unwanted Soldering Kits system signal and $25. desired plus Soldering /Desoldering Kits between life -like color Sharp, vibrant See your distributor or write... noise. its finest. listening at FM stereo 5127 EAST 65TH ST. Other configurations INDIANAPOLIS, You can easily work up other ar- INDIANA 46220 rangements for this low cost keyboard. PHONE 317/251-1231 Investigate now! Even if you only need a few pushbut- enterprise S & A ELECTRONICS tons for an electronic lock, music syn- 11 development Phone 419 -693 -0528 thesizer or game, this system easily corporation 202 W. Florence St. Toledo, Ohio 43605 adapts itself and its real beauty is that you can custom design your own. R -E Circle 67 on reader service card Circle 68 on reader service card 88 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com HANDY TRANSISTOR PULLER Here are details on a handy transistor puller that you can make in just TV TECH a few minutes. It was described in a recent issue of GTE Sylvania Service CHOPS DOWN Notebook. All you need is one alligator clip and a 3 -inch long thin screw PRICES FOR or bolt. WASHINGTON'S 3" BOLT ilIOOaoouoonnuaoaooun000unoaonuoouo BIRTHDAY! 12 REASONS MULLARD TUBES YOUR CAR NEEDS o\ 5 -3A3 $4.95 A TIGER 500 5 -6BL8 ALLIGATOR CLIP 3.00 5 -6BZ6 Instant starting in any weather - Eliminates 4.00 5-6DW4 tune -ups - Increases gas mileage - Increases 4.95 5 -6EA8 horsepower 15% - Improves acceleration & 4.75 5.6EH7 performance - Spark plugs and points last 4.25 O 5-6EJ7 up to 70,000 miles - Reduces engine main- ilm000aoo 10000 4.00 tenance expense - Amplifies spark plug 5-6FQ7 3.50 FINISHED PRODUCT voltage to 45,000 volts - Maintains spark 5 -6GY6 4.00 plug voltage to 10,000 RPM - Reduces 5 -6HZ6 3.50 exhaust emissions - Dual ignition switch - Use gas pliers to flatten and turn 5 -8FQ7 3.50 Unconditional guarantee for original owner up the tip of the lower jaw of the al- 5.6HB7(Admiral) 4.25 - Installs in 10 minutes on any car with 12 clip. The turned up tip forms a 300 volt negative ground - No rewiring - Most ligator Asst'd Resist. 182 Watt $4.95 powerful, efficient and reliable Solid State lip to catch the transistor case for bet- 100 Mica Cond. Asst'd $1.49 Ignition made. ter pull ability. Screw the bolt into the 20 Asst'd Mallory Controls $2.49 25 SATISFACTION GUARANTEED clip shank and solder securely as Asst'd Cond. (Cans) $4.95 or money back. 25 Asst'd Cond. (Axial) $4.95 shown. Assembled $49.95 Post Paid in U.S.A. DIODES -SEMI CONDUCTORS Send check or money order with order to: EXTENSION HANDLE HEP 170-2.5 Amp. 1000 PIV 25 for $4.95 FOR TWEEZERS 6500 PIV Focus Rect. 4 for $2.00 771:Star Corporation A handy extension handle for 13.5 KV Focus Red. 5 for $3.00 Dept. R, P. O. Box 1946 tweezers can be readily devised by us- 18.5 KV Focus Rect. 3 for $2.49 Grand Junction, Colorado 81501 Sel. Boost Red. 5 for $2.00 ing a spring -type clothes pin. Taper DEALER INQUIRIES INVITED Crystal Diodes 1N34A 25 for $2.00 Circle 72 on reader service card both jaws of the clothespin and attach the tweezers to one jaw with a strip of CONDENSERS -AXIAL LEADS

tape. Position the tweezers so the 25 mfd. 25 Volts 5 for $1.00 pincher ends are held closed by the 50 mfd. 50 Volts 4 for $1.00 spring action of the clothespin. When 50 mfd. 150 Volts 6 for $1.49 100 mfd. are opened, the 150 Volts 12 for $1.98 the clothespin jaws 1000 mfd. 50 Volts 6 for $2.49 tweezer also opens. 30 mfd. 450 Volts 6 for $1.98 CONDENSERS -(CANS) 300 mfd. 150 Volts 3 for $1.98 500 mfd. 200 Volts 2 for $1.98 300 mfd. 200 Volts 4 for $1.98 ° °°C PHONO EQUIPMENT %Q`p`C Mono Tone Arms TO Cart Modules, 2 for $2.19 ` Sneakers, Stereo Tone Arms TO Cart 2 for $2.98 ` Stereo, HI -FI, Photo Cells and Equiv. Astatic 133 Boxed $3.19 ea. thousands of Equiv. Asiatic 142 $2.79 ea. other Electronic, Equiv. Astatic 13TX Boxed $2.98 ea. Parts. Send for Equiv. Sonotone 8T Boxed $2.98 ea. FREE Equiv. BSR5H Boxed $2.49 ea. Catalog Equiv. Euphonics U -1 Boxed $2.49 ea. MI Equiv. EV 275 Boxed $3.59 ea. This quickly improvised tool (see Equiv. EV 5015 $3.59 ea. RCA Phono Plugs 10 for $1.00 gìd photo) is most effective in inserting Knife Switches DPDT 4 for $1.00 pins, screws and keys in close quar- 4 Align. Tools Asst'd. $1.19 ters. -Glen F. Stillwell R -E MINIMUM ORDER $15.00 SEND FOR FREE CATALOG 1.61 1111111111.1 NM . ELECTRONIC DISTRIBUTORS INC. TUBES UP TO 80% OFF Dept. TA-2, 4900 Elston Chicago, Ill. 60630 SEND CHECK OR RUSH CATALOG MONEY ORDER . Name TV TECH SPECIALS . Address P.O. BOX 603 City State Zip Code Kings Park, L.I., New York 11754 "Don't look now, but 1 think our chal- lenge of the day has arrived" Circle 73 on reader service card Circle 74 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 91

www.americanradiohistory.com 12 exciting new Heathkit® projects you can assemble Yourself (There are 350 more in your ...and sore! free '73 Heathkit Catalog)

NEW Heathkit 21V Color TV - NEW Heathkit Solid-State Plus Detent UHF Tuning... 499.95* less cabinet Ultrasonic Intrusion Alarm ...49.95* Power detent selection of all VHF and any 12 pre -selected UHF channels; Disguised as an ordinary library book, this novel device fits unobtrusively exclusive angular tint control for consistently better flesh tones; voltage anywhere in the home or office, yet detects any significant movement in the controlled varactor UHF tuner & MOSFET VHF tuner for unmatched sensitiv- room, ultrasonically. The transmitter disperses a 41 kHz signal which ity; black matrix tube, built -in dot generator, - convergence panel and volt bounces off walls & returns to the receiver where it's monitored for any ohm meter full remote - control options, too. It's Heathkit TV at its finest change in amplitude. The device triggers lights and any conventional alarm in a space- saving size. Kit GR -271, less cabinet, 121 lbs. device - just plug them into AC outlets on the rear panel. Can be installed anywhere there's a 120 VAC outlet. An enjoyable 2- evening kit a Assembled GRA-501-21, table model cabinet shown, ...for lifetime of reliable home security. Kit GD -39, 5 lbs. tough walnut Marliteg finish, 33 lbs. 54.95*

NEW Heathkit 30 MHz Counter... 169.95* NEW Heathkit 8- Channel VHF Band -

Gives 1 Hz to over 30 MHz counting on a full 5 -digit readout with 8 Scanning -digit Monitor with digital readout... 119.95* less crystals capability. The lighted overrange indicator makes misreading virtually im- Crystal -controlled monitor tunes any selected 9 MHz segment of the 146 possible. Stable timebase circuitry assures accuracy better than ±3 ppm through 174 MHz band - gives you police, fire, marine, ham 2- meter, etc. from 22° to 37° C. Diode protected J -FET gives improved triggering over Features manual or automatic scanning with numerical readout; priority 100 mV to 150 V input range. Solid-state circuitry mounts on one large channel; built -in speaker and rear -panel jack for remote board. Kit IB -1100, 6 lbs. speaker; gimbal bracket for either base- station or mobile use. Operates on either 120/240 VAC or 12 VDC. Includes crystal OSC /Mixer signal source for easy alignment. NEW Heathkit 21/2 -Digit VOM ... 79.95* Order up to eight Crystal Certificates with kit. Kit GR -110, 9 lbs. GRA-110-1, Four overlapping ranges to measure voltages from 10 mV to 1000 V on DC Crystal Certificate, postpaid each 4.95* (either polarity), 10 mV to 700 V rms on AC, 10 uA to 2.5 A on AC or DC current. Five resistance ranges measure from 1 ohm to 2 megohms. Front panel polarity switch reverses inputs without changing leads. Kit IM -1202, 6 lbs. NEW Heathkit Engine Analyzer...64.95* For 3, 4, 6 and 8- cylinder engines. Includes leads and accessories for test- NEW Heathkit /Thomas Spinet Organ ing conventional, transistor, and magneto ignition systems, regardless of voltage or grounding. Uses 3 "C" batteries (not included). Kit CM -1050, 9 with two 44 -note keyboards ... 689.95* lbs. Full 44 -note keyboards for Solo and Accompaniment, exclusive Color -Glo keys light * that up to indicate notes and chords. There are six solo stops, NEW Heathkit C -D Ignition System...39.95 five accompaniment stops, plus both regular and a new "light" vibrato ef- Increases spark -plug and fects. Other features include keyboard jacks for private earphone listening point life up to 50,000 miles on any car or truck using a 12 -volt, negative ground system. Automatically or use of a tape cassette deck. Cabinet is shipped fully assembled, includes varies spark duration. Screw -on bench. Kit TO -1160, 211 lbs. terminals make installation easy; external pushbutton lets you override system without removing leads. Kit CP -1060, 4 lbs.

NEW Heathkit 4- Channel Amplifier * with "Universal" decoder circuitry... 359.95* NEW Heathkit 6 -Digit Electronic Alarm Clock...54.95 Displays hours, minutes and seconds on highly visible cold- cathode readout You select discrete 4- channel, or switch -in the "Universal" decoder for re- tubes. A gentle "beeper" alarm can be set for 24 -hour cycle and features a production of all the matrixed 4- channel discs now on the market, plus snooze switch that gives you seven more minutes of sleep before the alarm "derived" 4- channel from conventional stereo. Four solid -state amplifiers sounds off again. Conventional 12 -hour or 24 -hour international time display. produce 200 watts (4x50 IHF) into 8 ohms, with power bandwidth on all Kit GC -1005, 4 lbs. channels from less than 5Hz to greater than 45 kHz at 0.25% distortion. Kit AA2010, 37 lbs. AAA-2004-1, pecan cabinet, 7 lbs. 24.95* NEW Heathkit Dolby" Cassette Deck...249.95* A kit -form cassette deck utilizing the famous Dolbyg noise reduction sys- NEW 4- Channel Heathkit "Universal" Decoder... 39.95* tem. Accommodates the greater fidelity and dynamic range of chromium Reproduces all matrixed discs, plus "derived" 4- channel from conventional dioxide cassettes. Independent switches provide Dolby on /off and regular stereo material. Plug it into your receiver's tape monitor circuit, add a sec- or Cr02 bias control. Domestic -make tape transport comes preassembled ond stereo amp and speakers and you're set. Kit AD -2022, 4 lbs. for easy kit building. Kit AD -1530, 21 lbs.

See them all at your nearest Heathkit Electronic Center... or send for FREE'73 Heathkit Catalog.

HEATHKIT ELECTRONIC CENTERS - ARIZ.: Phoenix, 2727 W. Indian School Rd.; CALIF.: rHEATH COMPANY, Dept. 20 -2 Anaheim, 330 E. Ball Rd.; El Cerrito, 6000 Potrero Ave.; Los Angeles, 2309 S. Flower St.; Benton Harbor, Michigan 49022 Pomona, 1555 Orange Grove Ave. N.; Redwood City, 2001 Middlefield Rd.; San Diego (La Please send FREE Heathkit Catalog. Mesa), 8363 Center Dr.; Woodland Hills, 22504 Ventura Blvd.; COLO.: Denver, 5940 W. 38th Ave.; CONN.: Hartford (Avon), 395 W. Main St. (Rte. 44); FLA.: Miami (Hialeah), Enclosed is $ , plus shipping. 4705 W. 16th Ave.; GA.: Atlanta, 5285 Roswell Rd.; ILL.: Chicago, 3462 -66 W. Devon Please send model(s) Ave,; Downers Grove, 224 Ogden Ave.; IND.; Indianapolis, 2112 E. 62nd Ave.; KANSAS: Kansas City (Mission), 5960 Lamar Ave.; MD.: Baltimore, 1713 E. loppa Rd.; Rockville, Name 5542 Nicholson Lane; MASS.: Boston (Wellesley), 165 Worcester St.; MICH.: Detroit, 18645 W. Eight Mile Rd. & 18149 E. Eight Mile Rd.; MINN.: Minneapolis (Hopkins), 101 Address Shady Oak Rd.; MO.: St. Louis, 9296 Gravois Ave.; N.J.: Fair Lawn, 35 -07 Broadway (Rte. 4); N.Y.: Buffalo (Amherst), 3476 Sheridan Dr.; New York City, 35 W. 45th St.; Jericho, City State Zip L.I., 15 Jericho Turnpike; Rochester, Long Ridge Plaza; OHIO: Cincinnati (Woodlawn), Prices & specifications subject to change without notice. 10133 Springfield Pike; Cleveland, 5444 Pearl Rd.; PA.: Philadelphia, 6318 Roosevelt *Mail order prices; F.O.B. factory. CL-153 Blvd.; Pittsburgh, 3482 Wm. Penn Hwy.; TEXAS: Dallas, 2715 Ross Ave.; Houston, 3705 Westheimer; WASH.: Seattle, 221 Third Ave.; WIS.: Milwaukee, 5215 Fond du Lac.

92 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com irrie .'00 an reader sJrvice card FEBRUARY 1973 RADIO -ELECTRONICS 95 www.americanradiohistory.com new books

MODERN RADIO REPAIR TECHNIQUES, by Arf Margolis. TAB Books, Blue Ridge Summit, Pa. 17214. 260 pp. 51/2" x 812 ". Hardcover, $7.95; Softcover, $4.95. The seasoned TV technician gains considerably from the numerous troubleshooting tips in this book. Beginning technicians, with a few hours study, begin to turn out profitable work. The book reveals many simple shortcuts and test techniques for making radio repair a profit- Clever Kleps able sideline or even a profitable main line of business. It provides up- FM, FM Test probes designed by your needs-Push to seize, push to -date service data on today's radio receivers, including AM, to release (all Kleps spring loaded). stereo and multi -band plus a foldout section containing complete sche- Kelps 10. Boathook clamp grips wires, lugs, terminals. matics for a dozen brand -name receivers. Directions on how to set up Accepts banana plug or bare wire lead. 43/4" long. $1.19 and equip a radio repair bench are included. Kleps 20. Same, but 7" long. $1.39 Kleps 30. Completely flexible. Forked-tongue gripper. Ac- BASIC COLOR TELEVISION COURSE, by Stan Prentiss. TAB Books, cepts banana plug or bare lead. 6" long. $1.47 Blue Ridge Summit, Pa. 17214. 420 pp. 5''%" x 81/2". Hardcover, $9.95; 40. flexible. 3- Kleps Completely segment automatic collet Softcover, $6.95. firmly grips wire ends, PC -board terminals, connector pins. A completely up-to -date textbook giving the beginning technician or Accepts banana plug or plain wire. 63/4" long. $2.39 in B Kleps 1. Economy Kleps for light line work (not lab quality). student a thorough background color and &W television receiver Meshing claws. 41/2" long. $ .99 basics. The text covers everything from the antenna to picture and Pruf 10. Versatile test prod. Solder connection. Molded sound. The book teaches how TV signals are "put together" at the phenolic. Doubles as scribing tool. "Bunch" pin fits banana broadcast station, radiated into the air and how these signals are jack. Phone tip. 51/2" long. $ .79 picked up by a receiving antenna, sent to the receiver and reproduced; All in red or black - specify. For additional information, how colors are mixed and reproduced on a picture tube screen. All cir- write for complete catalog of - test probes, plugs, sockets, cuits are thoroughly discussed, including brand -new receiver circuits connectors, earphones, headsets, miniature components. using transistors and integrated circuits and those used only for mono- Available through your local chrome reproduction. Also covered are cable systems and major for- distributor, or write to.. eign TV systems.

RYE INDUSTRIES INC. 99 WAYS TO IMPROVE YOUR HI -FI, by Len Buckwalter. Howard W. 127 Spencer Place, Mamaroneck, N.Y. 10543 p-ye Co., 3 W. 57 York, N.Y. 10019. 128 51/2" x it Inc., St., New pp. , N o u a T w t. a Sams In Canada: Rye Industries (Canada) Ltd. 8'h". Softcover, $3.50; In Canada, 58.35. Circle 75 on reader service card BUY RITE ANS SAVE Only applies FREE EVERY ORDER FREE $1 BUY WITH EVERY 10 YOU ORDER to "Sl" Boys GIFT WITH TRANSISTOR RADIO a, +t type 2 COLORBURST - UHF TUNER TRANSISTOR 53.95 51.50 - QUARTZ $1.89 .12.p" UNIVERSAL SPEAKER $4.89 - good. bad. broken, as -la, potluck CRYSTAL For Most Color TV Q Large U TYPE used in alt TV seta ... assorted types is 3579.545 KC STANDARD TUNER TRANSIS- TAPE RECORDER - 10" PHILCO SPEAKER S - 2.99 GRID) good. bad, broken, as 16, potluck .. 5A 2 ELECTROLYTIC CAPACI- Top Quality . . . Large Magnet TOR (GUIDED - 4 Channel closed circuit $l 300 - ASST. 1/2 W RESISTORS TSOR CD - 40/40 MFD - 450 51 8" UNIVERSAL SPEAKER - SO.99 Top Brand, Short Leads, Excellent $1 Volts Large Magnet -Special Buy .. PHILCO TV TUNERS Selection Malet -70- 13883 -3 (SGJ7- 54.95 SPECIAL TUBE BUY 51 5" UNIVERSAL TWEETER 51.25 3iiQ5) 100 -ASST 1/4 WATT RESISTORS S1 n 4 - 18F133 American made I Oz. . . . Magnet stand. choice ohmages, some in 5% GE - TV TUNERS 1 1 UNIVERSAL 4" PM SPEAKER S1 - -6" x 9" HEAVY DUTY 10 OZ Model -ET 86X314 - (5LJ8 -3GK5) $á.95 100 -ASST 1/2 WATT RESISTORS S1 SPEAKER Ceramic Type . . . . $3,95 Top Quality COIL TV stand. choice ohmages, some In 5.7 8 Ohm 21/2' x 4' SPEAKER 6`90 Ea. GE - STANDARD TUNER 1 WATT Special Buy 10 For 55- 70 - ASST RESISTORS 51 5 ASSTD. GLOBAR VARISISTOR Model EU SBXI (6HQS -6GJ7) stand, choice ohmages, some in 5 1_..J 16 OHM 57.9$ Popular replacements for most 51 4" X 6" "QUAM" Model -ET 88X304 (6LJ8- 2 RESISTORS Large magnet 51,79 - / 35 - ASST WATT $1 COLOR TV SPEAKER 611A5) stand, choice ohmages, some in 5% Special BUY (10 for $15.00) . 10 - SETS PHONO PLUGS IL j1 TV TUNERS VHF /UHF ell new $7.95 50 - PRECISION RESISTORS S1 RCA type RONETTE STEREO CARTRIDGE 52 makes, including asst. list -price $50 less 98 % PIN JACKS latest dual sapphire fllpover type standard Tubes PRINTED IF TUNER satt all new 51 20 ASSORTED WIREWOUND S1 8- CIRCUIT TRANS- S1 STEREO HEADPHONES TV - - FORMERS 4 -Lug, 456 KC standard makes, Less tubes.... RESISTORS, 5. 10, 20 won .. HI -Fi Quality . . Complete SG.95 ASSORTED SLIDE SWITCHES 51 25 - 3900-OHM-7w RESISTOR 51 with Stereo plug J 10- Corning SPST, SPOT, DPDT, etc. 10% glass COLOR POWER TRANSFORMER 20 - .47-600V CONDENSERS S1 - Good for most sets 26R150 $6.95 SARKES TARZIAN TUNER White Ceramic C.D. -American .... List Price- 536.75 v KNOB SPECIAL 41mc STEREO TONE ARMS Mont pop'. $2 4 -50' HANKS HOOK-UP WIRE S1 100 - ASSORTED RADIO lar type -turn over cartridge ... assorted colors KNOBS An standard types . . 51 CO -AX CABLE 1í059U grey or 52 100' -SPOOL SPEAKER WIRE S1.50 Latest Compact $20 value black 250' -19 1oo' -13.69 50'- 2 coed, mini sip, clear, 101 uses Model good for 50 TV KNOBS POPULAR - - 10 - ASST. RADIO 8 TV TUBES S1 41 TYPES Mostly Selector & Fine 4 - TV ALIGNMENT TOOLS Si Every Tube a good number all me TV's. 51 most useful assortment #1 Tuning 5 AUDIO OUTPUT TRANS- BRAND NEW- 4 - TV ALIGNMENT TOOLS 51.49 - 51 25 - VERTICAL LINEARITY TV #2 FORM Sub -min for Trans Radios Long eheok Front $1 For Color KNOBS 5 - I.F. COIL TRANSFORMERS mount . . (mature assortment 6 - TV COLOR ALIGNMENT 52.79 456.kc for Transistor Radios $1 TOOLS Most popuiar type 20 - VERTICAL LINEARITY 6" UNIVERSAL SP E AKER KNOBS . Side mount $1 5 -9 VOLT MOTORS Escellent 51 Top Quality Special buy sizes 51.29 Ea. Standard for hobbyist 5 for $5 Best TUNER " SARKES TAR - 25- KNURLED RADIO KNOBS S1 200' - #24 SOLID PUSH BACK ALL AMERICAN TUBE KIT $2.99 ZIAN" ever made -last word for Hard to get . Best selection WIRE Yellow or Black excellent 51 (12A V 6- 12BE6- 12BA6 -35 W 4 -5005) stability, definition & smoothness 40 - DELUXE RADIO KNOBS buy 70° COLOR TUBE BRIGHTNER $3.95 of operation. An opportunity-to Choice assortment . Popular $1 TV improve and bring your TV Re- OP*. UNIVERSAL ANTENNA Back of set mounting 51,98 900 COLOR TUBE BRIGHTNER $4.951 ceiver up- to-date. $795 ANY 6 KITS FOR S5 5 section rods COMPLETE with Tubes IMMEDIATE DELIVERY Scientific light packing for safe delivery at minimum cost. Name Cost of ... goods HANDY WAY TO ORDER: Pencil mark or write amounts wanted in each box, place letter Address Shipping F in box for Free $1 BUY. Enclose with check or money order, add extra for shipping. estimated Tearsheets will be returned as packing slips in your order, plus lists of new offers. TOTAL Minimum Order $3.00 Please specify refund on shipping overpayment desired: CHECK POSTAGE STAMPS MERCHANDISE (our choice) with advantage to customer BROOKS RADIO & TV CORP., 487 Columbus Ave., New York, N. Y. 10024 2TEiStc54E 96 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com All inclusive coverage on methods for improving your hi -fi and stereo sound systems. Many items are simple adjustments that can be performed at little or no cost. Only very basic technical knowledge or none at all is required to follow the instructions and no special tools are required. Some of the topics covered are installation of the hi -fi, FM stereo reception, phonos and turntables, amplifiers, tape equipment, speakers, stereo headphones and microphones, accessories, and troubleshooting tips.

101 QUESTIONS d ANSWERS ABOUT AM, FM, & SSB, by Leo G. Sands. Howard W. Sams d Co., Inc., 3 W. 57 St., New York, N.V. 10019. 96 pp. 51" x 81/2". Softcover, $3.95; in Canada, $4.95. Questions and answers covering both the history and basic technical aspects of the three types of modulation as well as receivers that are used for demodulation. Divided into three parts, the guide contains material concerning the advantages and disadvantages of each modulation and demodulation method as well as the basic circuits employed in the process. Examples of questions answered are what is a noise blanker, why do most mobile stations use FM, and how is SSB used in telephone systems.

PRACTICAL SOLID-STATE PRINCIPLES d PROJECTS, by Ken Ses- sions. TAB Books, Blue Ridge Summit, Pa. 17214. 176 pp. 51/2" x 81/2". Hardcover, $6.95; Softcover, $3.95. A project- oriented approach to learning about the latest semiconductor devices and circuits anyone can understand and build; projects such as an electronic burglar alarm, a solid -state timer, a metronome, an automatic night light switch. Fifty -two unique projects, some with multiple applications, include Citizens band receiver, stereo amplifier, integrated circuit code -practice tone oscillator, battery charger, precision tachometer and many more practical projects. R -E Circle 76 on reader service card - SHANNON MYLAR RECORDING TAPE- CANADIANS: Ordering is easy - we do the paperwork - by a small order 3" - 225' .. .19 CASSETTE C -60 .59 CASSETTE C -90 a-r 31/4" 600' .58 1.00 WESTINGHOUSE ALL TRAN- IBM S CONSR - CASSETTE C -120 (TDK) 1.97 are .62 8 assorted Unit. 8 Track - 64 Min, - 1.29 SISTOR HOME /OFFICE sell for tl w 900' .80 - loaded with oren 5" - 8 Track - 80 Min. - 1.59 150 valuable parta. 1200' .. .97 8 -Track - Cleaner - 1.49 MESSAGE CENTER S" - fnel. - Transistor. 5" -1800'., 1.49 Leaves messages for other for replay . Built in Condensen, Reels. speaker /microphone for talk -into convenience . , . Re- ton, Rest Sinks. 7" 1200' .77 Diodes, ase. - 3" TAPE REEL .... .06 corda up to 8 minutes of messages . Illuminated 1800' 1.12 signal shows when a message is waiting. Control 7" - .. 3 1 ' TAPE REEL .07 /4 ... adjusts playback volume without affecting recording ... 51 7, - 2400' .. 1.79 S" TAPE REEL .... 14 volume Capstan Drive ; $795 7" 2.95 7" TAPE REEL .... .11 BRAND NEW SOLD AS TS 100 Fer ;10

RCA 110 FLYBACK TRANSFORMER COLOR -TV RECTIFIER - WESTINGHOUSE FM TUNER $2.99 MARKET SCOOP COLUMN Uaed in most color Bets- $1.93 (12DT8 Tube) Vie ¡mooned the M 8500 Latest type - standard SIMPSON 21/2" ROUND kv 3 for as WESTINGHOUSE FM TUNER for all 110 TV's o PANEL METERS Model 125 $3.95 10 STANDARD TRANSISTORS - 51 #476-V- O15DO1 . Transis- 5 RCA' deafen of large (0.100 DC Milllammeters).. NPN PNP 2N404, 2N414. etc. .. 3.99 Coil produce@ 185V tor assuring adequate wid SIMPSON 21/2" ROUND 10- ASSORTED DIODE CRYSTALS Incl Schematic Diagram o PANEL METERS Model 125 5 1,95 1H34, 1N48. 1N60, 1N64, ete. 51 300 ASSORTED HEX NUTS S1 application for any TV (0 -10 DC Milllammetere 2/56,- 4/40, 5/40, 6/82, 8/32 .. List price 513.90 ASIATIC PICKUP MODEL 700. 6 - TOP BRAND SILICON REC- S1 1 amp. 1000 PM 89T Contains 89T ceramic ear- 50).95 TIFIERS 250 - ASST. SOLDERING LUGS 51 :3 trldge LIST PRICE 917.00 best types and sines Tour price .. 2 5 -e PNP TRANSISTOR 20 - DIPPED MYLAR CAPACI- 51 general purpose, TO.S casa $1 10% as In lots of 3 .01 -800V 250 - ASST. WOOD SCREWS S1 TORS s - NPN TRANSISTORS finest popular Wootton 20 - DIPPED MYLAR CAPACI- S1 general purpose, T0.5 cafe si TORS .033 -800V 250 ASST. SELF TAPPING 50 ASSORTED TRANSISTORS - S1 TV - 51 , etc. 110 DEFLECTION YOKE $2.95 20 - DIPPED MYLAR CAPACI 51 big factory scoop-sold as.1s SCREWS #6, 1.__J for all type. TV's iucl echomatic TORS .0033 -1000 V .... 20 DIPPED MYLAR CAPACI- TV TWIN LEAD -IN 900 ohm 150 - ASST#6. 6/32 SCREWS S1 - 500' 97 100'-a1.50 :1 "COMBINATION SPECIAL" TORS .047 -400 V. 51 - 50' - and 150 6/32 HEX NUTS RCA 110° FLYBACK $ C.9S 15 - MOLDED TUBULAR CA- 51 12- MINIATURE ELECTROLYTIC plus 110° DEFLECTION YOKE o PACITORS 068 --400 V. CONDENSERS For Transistor & $1 150 - ASST. 8/32 SCREWS 51 miniature work and 150 -8/32 HEX NUTS 20 - DIPPED MYLER CONDENS- S1 90° FLYBACK TRANSFORMER $2.95 ERS .0039 -400 V. for all type TV's foci schematic 6 - MINIATURE ELECTROLYTIC 51 150 ASST. 2/56 SCREWS S1 5 MFD V. - 10 - SPRAGUE "ORANGE CAPACITORS -150 and 150 -2/56 HEX NUTS 90° TV DEFLECTION YOKE 52.95 á DROP" CAPACITORS 3- ELECTROLYTIC CONDENSERS for all type TV's 1nc1 .0056-2000 Volt :1 schematic 100 mfd. -100 V, 50 mad -75 V . 150 - ASST. 4/40 SCREWS S1 1 - 20 FT. COILED GUITAR 52.95 and 150 -4/40 HEX NUTS 70° FLYBACK TRANSFORMER CABLE With plug, 2- ELECTROLYTIC CONDENSERS S1 for all type TV' mcl schematic .. 52 C.D. 500 mfd -200 volts 150 ASST. 5/40 SCREWS 1- CASSETTE TYPE DYNAMIC - Si MICROPHONE with unlvereal 52.49 ELECTROLYTIC and 150 -5/40 HEX NUTS 70° TV DEFLECTION YOKE á 2- CONDENSERS S2 plugs --200 Ohms UNECAP .. 2000/1000 Mid 51 for all type TV' Mel schematic . 500 ASSORTED RIVETS S1 COLOR CONVERGENCE 30 Volt mort -useful selected aise. SHARP 110° FLYBACK & Universal ASSEMBLY type- 52,49 2 ELECTROLYTIC YOKE COMBINATION #8FT- good for most sets - CONDENS- S1 55.00 ERS ao /somra -450V, zomra -2soV 300 - ASSORTED WASHERS :1 592 Good for most portable TV. useful selected saes UTAH "CELESTA" 3-WAY 150mÍ4 -25V most 8 "-loos. 90° COLOR YOKE For all $10,95 COAX SPEAKERS 100 ASST. RUBBER BUMPERS 51 Rectangular Mag. -30 Watte $16.95 2 - ELECTROLYTIC CONDENS- 51 - 19ío25 "ColorCRT's bottoms . . 200/30/4 mid 350V for cabinet & other use. UTAH "CELESTA" 3 -WAY ERS - ... Part in RCA COLOR FLYBACK $12.95 CO -AX SPEAKERS 12 " -20oz. 524,95 HEAVY DUTY COLOR FOCUS S1 100- ASSORTED RUBBER GROM- S1 #113382 (Stancor #H0.601C) 11 Mag. -45 Watts RECTIFIER 14.000 rr., @ 1 M..A METS twat sise. Circle 77 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 97

www.americanradiohistory.com Pioneering again Castle presents a sensational NEW Timesaver for the Professional TY Service Technician TV TONER SOlDERM circuits

TOUCH OR PROXIMITY SWITCH This circuit can be adjusted to switch when a human body approaches to within a few inches of an insulated detector plate. Thus, it can be used as an electrically isolated touch switch or a part of an intruder alarm. The design was credited to International General Electric Co. of New York in Electronic Engineering magazine. The PUT (programmable unijunction transistor) turns on when its anode voltage exceeds the gate voltage by about 0.5 volt. Its anode voltage is held constant at the

10 MEG 47K I LOAD SENSITIVITY o LINE Transistorized Test Unit substitutes the tuner in defective TV Receiver to prove whether (117V, 60Hz) original tuner is good or bad. Performs tests normally mode using elaborate and expen- 1 MEG sive signal generating equipment and oscilloscopes ... but much more simply, with 1 MEG easily understood results. Tests that ore, in fact, so simple that they can be made right in the hors, in most cases without removing the tuner or chassis from cabinet. C10681 Use with any 40MHz receiver ... block and white or color ... tube or transistor. SCRY Completely self contained and battery operated; Mk. Il, all solid state, improved version of original "subber." Uses L.E.D. indicator, has higher gain with wide range control affording more than 40db of INSULATED gain reduction. 1K Use on the bench or in the home .. , anywhere. TOUCH PLATE Substitutes the VHF tuner and tests the UHF tuner. Provides signal to simplify testing of tuner, i.f. system and AGC system. Comes complete with extension cables and instructions. "on" voltage of the diac. A body approaching the detector

TV TUNER SUBBER MK. II net $31.95 contact your distributor. plate changes the capacitance between the plate and Includa $1.30 shipping cnd handling on prepaid moil orders. on nail ship C.O.D. ground. This change in capacitance causes a shift in the CASTLE TV TUNER SERVICE, I N C. phase angle between the PUT's anode and gate voltages. 5715 N. Western Ave.. Chicago. Illinois 60645 . rhon. (312) - 361.835e The phase angle widens until, at some time, the voltage Circle 78 on reader service card difference is high enough to fire the PUT. The voltage developed across the 1000-ohm resistor fires the SCR used as Accuracy like a VTVM... the solid -state relay controlling the load. The SENSITIVITY control determines the voltage level at which the PUT's an- Convenience like a VOM... ode is clamped. NEW BATTERY -OPERATED FET MOBILE POWER SUPPLY FOR SOLID -STATE VOLT-OHMMETER'--116 CASSETTE RECORDER Quite a few business men use a cassette recorder in Easy -to -build KIT their cars for recording dictation, keeping records, etc. These recorders get fairly heavy use and the batteries seem 116K to go dead just when the driver is many miles away from a $3Ó.9ó store where replacement batteries are available. Factory-Wired &Tested The diagram shows a simple regulated supply for op-

ON 2%" X 2 '/" TO $42.90=116W HE ATS INK RADIO Now you can get all the benefits of a +12V AT OR VTVM (laboratory accuracy, stability and BATTERY 2N3055 RECORDER wide range) but with its drawbacks gone: no plugging into an AC outlet, no waiting +6 -7.5V for warm -up, no bulkiness. New Field Effect Transistor (FET) design makes possible low loading, instant -on battery - operation and small size. Excellent for both bench and field work. Compare these valuable features: High impedance low loading: 11 megohms input on DC, 1 megohm on AC EMC 500 -times more sensitive than a standard Send FREE catalog of complete line 20,000 ohms -per -volt VOM Wide-range and name of nearest distributor. RE.2 versatility: 4 P -P AC voltage ranges: 0 -3.3, 1200V; 4 RMS AC voltage ranges: 33, 330, Name 0 -1.2, 12, 120, 1200V; 4 DC voltage ranges: 0 -1.2, 12, 120, 1200V; 4 Resistance ranges: 0-1K, 0 -100K, 0-10 meg., 0 -1000 meg.; Address 4DB ranges: -24 to +56DB. City erating 6 -7.5 -volt portable radios and cassette recorders Sensitive easy -to -read 41/2" 200 micro - amp meter. Zero center position avail- 7ip from the car's 12 -volt battery. The circuit is adapted from able. Comprises FET transistor, 4 silicon State transistors, 2 diodes. Meter and tran- Radio Electronica (Netherlands). The 2N3055 transistor sistors protected against burnout. Etched should be mounted on a good heatsink at least 21/2 inches panel for durability. High- impact Bake- lite case with handle useable as instru- EMC square. The heatsink and case of the transistor must be in- ment stand. Kit has simplified step -by- ELECTRONIC MEASUREMENTS CORP. Both kit sulated from ground and possible contact with the body of step assembly instructions. and 625 Broadway, New York, N.Y. 10012 factory -wired versions shipped complete the car. Use the 500 -ohm pot or adjustable resistor to set with batteries and test leads. 51/4 "H x 63/4 "W x 27/e "D. 3 lbs. the output voltage to the desired level.

98 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com E, ONE WORD DIRECT- READING CAPACITANCE METER Reduce Car PERFORMANCE The average technician's or experimenter's workbench is equipped Maintenance RELIABILITY IN for nearly any type of test or operation imaginable except for quick ca- Increase IONITI pacitance measurements. The diagram shows a simple capacitance meter for measuring capacitance from I micro - Engine farad down to a few picofarads. (G3XGP called it "The Puffmeter" Performance. when he described it in Radio Com- munication.) Put a Mark Ten Capacitive Discharge Ignition (CDI)

__ o:'E=T System On Your Car.

YOU CAN HAVE TOMORROW'S IGNITION ON PANSISTOPS SEE TEXT ó. 0.1,0 C5,11 l E YOUR CAR TODAY I. E `E Proven by over 100,000 in operation for over five years. Transistors Q l and Q2 along with Even Detroit finally recognizes that elec- R I, R2, potentiometer R3, the capaci- tronic ignition systems dramatically in- Don't accept "as good as" there are tor selected by Sl -a and the base - crease engine performance. Chrysler is now emitter junction of Q3 form a regen- putting them on their new models. The Mark none. Ten COI, the original electronic ignition erative -type ramp generator. The saw - Write Today for Literature system. has been giving increasec perfor- tooth -like ramp voltage is converted to mance with lower maintenance to hundreds a square wave by Q3 and Q4 and fed of thousands of satisfied customers for C) mir through the unknown capacitor or one over eight years. Install a Mark Ten CDI on RESEARCH AND MFG. CO. boat or truck and eliminate 3 out O of the standard capacitors (C7 through your car, CONSHOHOCKEN PA.19428 of 4 tune-ups. Increase gasoline mileage up C12). The capacitor and diode D1 tp 20%. Enjoy improved engine perfor- Circle 79 on reader service card convert the square wave to a sharp mance. Or put a Mark Ten B on your car. It positive pulse whose amplitude is de- was especially designed for engines with smog control devices. By reducing combus- termined solely by the value of the cation contaminants, the Mark Ten B restores pacitor. The diode current is related to power losses caused by these devices. frequency and capacitor value. The Equipped with a convenient switch for meter integrates these values. If the instant return to standard ignition, the Mark Ten B is applicable to ANY 12 volt negative FREQUENCY control is varied so the ground engine. Both systems install in 10 meter reads fullscale on any range minutes with no rewiring. Order a Mark with a standard capacitor, the un- Ten or Mark Ten B CDI today. known produces a reading in direct Mark Ten (Assembled) $44.95 ppd. unique tools, proportion. Mark Ten (DeltaKit) $29.95 ppd. (Kit available in 12 volt only; handy kits, Q1 must be a high -gain pnp tran- positive or negative ground.) sistor such as a 2N4125 or 2N4288. Q2 Mark Ten B $59.95 ppd. (12 volt negative ground only) precision is an npn device such as a 2N3493 or Superior Products at Sensible Prices instruments, a low -gain 2N706. Q3 and Q4 may be Mfg. in U.S.A. a 2N706 or any small -signal npn tran- technical sistor. Dept FE'. supplies. To use the capacitance meter, connect the unknown capacitor across DELTA PRODUCTS, INC. the S2 to CALI- P.O. Box 1147 /Grand Junction, Colo. 81501 Our year of service to the World's test terminals. Throw 20th (303) 242 -9000 BRATE and move switch S I to the finest craftsmen and technicians. range of the probable value of the un- Please send me free literature. Natrona Camera known. Rotate pot R6 for a fullscale Enclosed is $_ Ship ppd. Ship C.O.D /\ 2000 west union Are. Dept.Ges reading on the meter. Throw S2 to V Englewood, Colorado, 80110 Please send: TEST, The meter now reads in direct _Mark Ten B @ $59.95 ppd. NM --a t-I =MI ttr7 Standard Mark Ten (Assembled) Send a FREE copy of the ne Flasher proportion to the value of the stan- i dard capacitor. @ $44.95 ppd. Neg. Ground Only Accuracy of the instrument de- _6 Volt: _12 Volt: Specify I name pends on the precision of the standard Positive Ground - Negative Ground I capacitors (C7 through C 12). You can Standard Mark Ten (Deltakit"')@ address purchase one precision -1% or better $29.95 ppd. I - capacitor and use it as a standard (12 Volt Positive Or Negative Ground Only) city Car Year Make I when hand -picking the others from or- Name state zip dinary stock. For example, suppose that for CIO (1000 pF or .001 µF) you Addreaa Nationa Camera I City /State Zip /\ 2000 west Union Ave. Dept. GIB have a 1% or better tolerance device En. lewood, Colorado, 80t I0 (continued on page 104) L_ _ _J Circle 80 on reader service card Circle 81 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 99

www.americanradiohistory.com YOU CAN BUILD ANY next month CIRCUIT IN 3 EASY STEPS MARCH 1973 WITH THIS FREE VEROBOARD SAMPLE This stereo spectacular issue is crammed with high -fidelity articles of all Veroboard is the universal wiring kinds. board that eliminates the need for etching, wires, or terminals - the circuitry is built right into the board! It is the Build A Four -Channel Power Amplifier simplest, fastest method Each channel delivers 60 -watts sine - of circuit building for the technician, engineer, wave continuous output into an 8 -ohm hobbyist or experi- load with less than 0.01% IM. It's a menter. Send for your real powerhouse. free sample now and we'll send you our brochure, "Everything you want to know about Veroboard." 4- Channel Tape For Your Car VERO ELECTRONICS, INC. A survey of what's available and in VOPO 171 BRIDGE ROAD, HAUPPAUGE, N.Y. 11787 what configurations. A story you must read before buying an add -on tape Circle 82 an reader service card system.

MISSILE Off -Beat 4- Channel Speaker Systems BATTERY For Flat styrafoam, acoustic transducers, pictures, balls, cubes, lamps col- The Only all you Lifetime Battery faster umns- they're speaker systems should know more about. Surplus -Ni -Cad plastic sinter- ed -plate battery cells at approx. 10% of government cost service Tape Bias And Magnetic Recording Connect these 1.2 V. cells In series to make batteries of any voltage. (Example: 10 cells = 12 V. Batt.), or size to replace storage batteries on autos. motor- How much effect does the bias have? cycles, boats, radio, etc. All the good characteristics not possessed by lead -acid and other alkaline bat- We tell you and show you with a set teries such as: Lifetime service, lighter wgt., constant voltage, high discharge rate (approx. IO times Alf cap.), operate at 100% cap. In temp. range USE of scope pictures. You may not be- -65° to +165 °F., not harmed by storage, discharge, overcharge. or freezing. May be charged lieve the results. thousands of times with the only maintenance of adding distilled water and keeping clean. Select cell sizes to flt your application below. ZIP Ease AMI' Dimensions Inches Wet. Type Hr High Width Deep Oz. Cost AH4 4 6 2 1/2 6 1.49 PLUS: AH4 4 6 2 1/2 6 '2.95 AH6S 6 4 2 -I/8 15/16 8 1.79 AH6 6 4.5/8 2 -5/8 3/4 8 1.79 CODE State -Of -Solid State AH6 6 4 -5/8 2-5/8 3/4 8 '2.95 A H 10 10 4.3/4 2 -3/4 -3/16 16 2.29 Plug -In- Stopwatch A H 10 10 4 -3/4 2 -3/4 -3/16 16 '4.95 AH12 12 5.3/4 2 -5/16 -1 /16 18 2.79 AH15 15 7 2 -3/8 -I /I6 18 3.49 Step -By -Step Troubleshooting AH2O 20 5-1/2 3 -1/8 -5/8 30 7.95 AH34 34 9 -1/4 3.1/8 -3/8 52 8.95 New on SPECIAL CLOSE OUT! Metal cased NI -Cad cells, ideal for motor starting. We were unable to kick off the Semicon- 30AHM -30ÁH, 8- 7/8æ3z1.1/9, Wgt. 3 -1/2 lbs. $2.00 52AH M -52A1-1. 9x3x1 -5/8, Wgt. 9 -1/2 lbs. ...$3.50 all ductor Interchangeability Directory in this Send for complete list including made -up batteries. All cells guaranteed for satisfaction or money back. All cells not marked new are used but serviceable. issue because of last minute delays in Include on post shipments. postage parcel verifying the data. Rather than take a ESSE RADIO COMPANY mail Dept. RE -2 chance on unnecessary errors we de- 368 8. Meridian St. Indianapolis, Ind. 46225 cided to delay presenting the first section until the March issue. Circle 83 on reculer service card 100 RADIO-ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com IMPOSSIBLE? BARGAINS IN SURPLUS ELECTRONICS AND OPTICS

NEW - COSMOS WAVEFORM GENERATOR, BF -5 SINGLE CHIP 7- SEGMENT INTEGRATED CIRCUIT Just one of these BF -5 devices DISPLAY COUNTER, AND DECODER. produces sine, square, traingle, Said to be the "New Wave' in integrated circuits of That's right! A single chip TTL decade ramp and sawtooth waveforms the future. Ultra low power drain counter with latches, BCD outputs, a (microwatts) without additional active com- 7- segment decoder driver, AND a 7- 4000AE Dual 3 Input Nor & Inv S .99 adding a second ponents. By segment LED display with decimal) 4001AE Quad 2 Input Nor $ .99 BF -5, you can create amplitude, on top. Only 0.15" thick not counting 4002AE Dual 4 Input Nor S .99 frequency or phase modulated pins), the chip mounts in a standard 4006AE 18 Stage Static Shift varieties of these waveforms. 16 -pin DIP socket. Digits are 0.270" Register $4.99 They are able to replace large high and can be latched in during the 4007AE Dual Complementary waveform generators discrete next count or blanked. Pair & Inv ...... $ .99 costing from $200.00 to 4009AE Hex Buffer, Inverting $2.19 $1300.00. At the same time, they 0.27 DLD $15.00 4010AE Hex Buffer Non Inverting .. $2.19 greatly reduce system weight and power consumption. 4011AE Quad 2 Input Nand $ .99 Full technical data, P.C. layout, assembly, and hook- 70 WATT RMS AUDIO AMPLIFIER 4012AE Dual 4 Input Nand $ .99 up instructions included. 4013AE Dual "D" Flip Flop $1.99 BASIC PACKAGE, STEREO $5.50 8F-5 WAVEFORM GENERATOR .... $ 9.75 4014AE 8 Stage Static Shift Take advantage of Signetic's Register $5.99 /e\ NE540 power driver, (class AB 4015AE Dual 4 Stage Static Shift GENERAL ELECTRIC PA -234, 1.4 -WATT I' amp). Designed for 35 watts RMS Register $5.99 POWER AMPLIFIER, $1.25 per channel. Distortion .5% fre- 4016AE Quad Bilateral Switch $1.99 quency response, t .5db 20Hz to This amplifier is housed in a 4017AE Decade Counter W /Decoder $5.99 100 Hz. NE540 requires two plastic dual in -line package with a 4018AE Presettable Donde by power transistors, a 2N5296 tab for heat transfer. Has only "N" Counter $5.99 (NPN) and a 2N6109 (PNP), sup- four active terminals, and requires 4019AE Quad and /or Select Gate $2.39 plied per NE540. Kit package only one capacitor for stabiliza- 4020AE 14 Stage Binary Ripple includes 121 NE540, (2) 2N5296, (2) 2N6109, infor- tion. Compatible with 8, 16, or Counter $5.99 mation on P.C. board layout, parts and circuitry, and a 22 -ohm loads. Applications in- 4021AE 8 Stage Static Shift list of miscellaneous small parts required to build the Register $5.49 dude P.A. systems, phonos, movie projectors, TV, AM 70 watt amplifier for stereo. and FM receivers. 4022AE Octal Counter W /Decoder $5.19 NE540 $2.25/ea. 4023AE Triple 3 Input Nand $ .99 PA -234 POWER AMPLIFIER $ 1.25 2N5296 35 watt NPN .75 /ea. 4024AE 7 Stage Counter $3.99 2N6109 40 watt PNP .75 /ea. 4025AE Triple 3 Input Nor $ .99 GENERAL ELECTRIC PA -265 70 watt Stereo Kit $5.50 /ea. 4026AE Decade Counter/? 35 watt Mono Kit $2.95/ea. Segment Decoder $7.49 5 -WATT VOLTAGE REGULATOR 4027AE Dual J -K Flip Flop $2.99 Housed in plastic dual in -line package with staggered FAIRCHILD VOLTAGE REGULATORS 4029AE Presettable Up /Down leads and power tab. Usable over wide range of input Counter $7.99 and output voltages, input voltages to 37 volts and This is the UA 7800 Series. Three terminal regulator, with thermal over- 4030AE Quad Exclusive Or $1.99 outputs from 3 to 30 volts. Usable in a wide variety of 4033AE Decade Counter/? circuits. load protection and internal current Segment Decoder $7.49 limiting, matting it essentially blow -out PA -265 VOLTAGE REGULATOR . .. $ 1.25 proof. Because simple circuitry is used with this device, designing regulated SUPER QUALITY I.C. SOCKETS power supplies is duck soup. Output is SPECTRA STRIP FLAT BONDED rated at 0 to 1 ampere; maximum - Sockets made by T.I. and Cinch. input voltage is 35 volts. Choice of We know this is what everyone wants All are low- profile, compact voltages: 5, 6, 8, 12, 15, 18, or 24 Volts. Order as for their home -brew projects, because types. they always ask for it. We now have 7805, 7806, 7808, etc. 14 Pin Dip Solder Tale Sockets over 5 by 10° feet, but it won't last Voltage Regulator (Sepcìfy Voltage) $2.00 3 for $1.25 16 for $5.00 .... long, so order now before it's all gone. 16 Pin We don't want any broken hearts. Dip Solder Tale Sockets 2 for $1.00 13 for $5.00 PRINTED CIRCUIT MATERIAL Specs: 20 conductors, 24 AWG, 7 or double strands, size is .88" x .044 ". We could 14 Pin Dip Gold Wire Wrap Socke Epoxy glass G10 material. Specify single give all its virtues, but most people 2 for $1.25 10 for $5.00 copper clad. Thickness 1 /16 inch 16 know them or could easily look it up in any industrial Pin Dip Gold Wire Wrap Socket 4 x 12 Sheets $1.00, 5 for $ 3.50 electronics house catalogue. 2 for $1.50 8 for $5.00 12 x 12 Sheets $2.50, 5 for $10.00 10 Pin to 5 Gold Sockets (Cinch) 110 Sh. Wt. 116./10 feet Order No. SSFBRC (ft.) Assorted cut pieces at least 2 for $1.00 13 for $5.00 4" x 4" 2 square feet $2.50 $ .35/1 ft. $ 1.00/3 ft. $ 5.00/18 ft. 14 Pin Right Angle Socket. Used to mount L.E.D.` 0$30.00/100 ft. $ 55.00/200 ft. 0 $100.00/400 ft. displays directly to P.C. board at correct viewing TTL INTEGRATED CIRCUITS $200.00/900 ft. $500.00/2000 ft. angle $1 00 Unfortunately we have had to raise our TTL prices CALCULATOR CHIP SPECIAL!!! due to a shortage of material. The following are our SANKEN HYBRID AUDIO new prices. Deduct 15% for 10 or more assorted, 20% One of the largest manufacturers of for 50 or more. AMPLIFIER MODULES MOS Integrated Circuits has discon- SN7400 $ .25 SN7447 1.50 SN74121 .49 We have made a fortunate pur tinued his three-chip set in favor of a SN7401 .25 SN7448 1.25 SN74122 .65 chase of Sanken Audio Amplifier single chip. This is the hobbyist's gain, SN7402 .25 SN7450 .25 SN74123 .99 Hybrid Modules. With these you since he can now obtain this fully SN7403 .25 SN7451 .25 SN74141 1.45 can build your own audio amp tested, highly flexible set at a fraction SN7404 .28 SN7453 .25 SN74145 1.25 lifiers at less than the price of of what even the largest calculator SN7405 .27 SN7454 .25 SN74150 1.25 discrete components. Just add a manufacturers pay. Consists of three 24 has input, SN7406 .45 SN7455 .25 SN74151 1.13 power supply, and a chassis to act -pin I.C.'s, debounced -digit capacity, SN7407 .45 SN7460 .21 SN74153 1.25 as a heat sink. Brand new units, in eight decoded seven- segment output. Full data SN7408 .29 SN7470 .39 SN74154 1.95 original boxes, guaranteed by B included. SN7409 .29 SN7472 .32 SN74155 1.39 and F, Sanken, and the Sanken U.S. distributor. 8-Digit Floating -Point Calculator Set . . . . 59.75 SN7410 .25 SN7473 .44 SN74156 1.39 Available in three sizes: 10 watts RMS (20 watts music SN7411 .25 5N7474 .39 SN74157 1.25 power), 25 watts RMS (50 watts M.P.1, and 50 watts LOGIC AND OPERATIONAL SN7413 .75 SN7475 1.00 SN74158 1.48 RMS (100 watts M.P.) per channel. Twenty -page SN7416 .48 SN7476 .44 SN74160 1.79 manufacturer's instruction book included. Sanken AMP. SUPPLIES SN7417 .48 SN7480 .65 SN74161 1.79 amplifiers have proved so simple and reliable that they 1 Figure A, plotted logic supply, 5 Volts at SN7420 .25 SN7481 1.10 SN74162 1.79 are being used for industrial applications, such as servo Ampere, short circuit proof, ultra high regulation, SN7421 .25 SN7482 .88 SN74163 1.79 amplifiers & wide band laboratory application. ultra low ripple $16.00 SN7426 .32 SN7483 1.25 SN74165 3.50 Figure A, potted Op Amp supply, +15 Volts, and 511010Y 10 watts SN7430 .25 SN7486 .49 SN74180 1.10 RMS amplifier, -15 Volts at 0.5 Amperes. Mfg. by Analog Devices, industrial grade $ 4.75 SN7432 .25 SN7489 3.50 SN74181 4.50 similar to their model 902. Short circuit proof, ultra SN7437 .50 SN7490 1.00 SN74182 1.10 S 11025A 25 watt RMS amplifier, high performance $29.00 industrial grade $14.75 SN7438 .51 SN7491 1.10 SN74184 2.50 Figure B, 5 Volt 1 Amp supply, regulated by 511050A 50 watt RMS amplifier, SN7440 .25 SN7492 .71 SN74185 2.50 Fairchild 9305, short circuit protected . . $ 9.75 industrial grade $22.50 SN7441 1.30 SN7493 .71 SN74192 1.75 Same as above, in kit form $ 7.75 SN7442 1.12 SN7494 1.10 SN74193 1.75 511025E 25 watt RMS amplifier, for above $ 1.00 Mating connector SN7443 1.21 SN7495 .95 SN74195 1.19 economy grade $14.00 5 5 regulated Volt Amp supply, by Blulyne, SN7444 1.21 SN7496 1.10 SN74198 2.65 S 11050E 50 watt RMS amplifier, (not shown) $29.00 economy grade $21.00 SN7445 1.50 SN74100 1.41 SN74199 2.65 Op amp and logic supply. Supplies t 15 volts at 100 Transformer for stereo 10 -watt SN7446 1.50 SN74107 .49 milliamperes and 5 volts at 1 ampere. Similar to amplifiers lbs.) $ 3.95 (2 Figure "B" but larger. Ultra -low ripple Built by CATALOG. Check reader's card or write. for stereo 25 or Transformer Elcom $32.50 50 watt amplifiers (5 lbs.) S 5.95 ALL ITEMS (WHERE WEIGHT IS NOT SPECIFIED' Set of (3) 2000 mfd 50V capacitors POSTAGE PAID IN THE U.S. A. for 10 -watt stereo $ 4.00 64 CHARACTER ASCI CODE CHARGES WELCOME! Set of (31 2200 mfd 75V capacitors ALPHANUMERIC L.E.D. DISPLAY for 25 or 50 watt amplifiers $ 5.00 Phone en charges to 617 5315774 617 532 2323 4 Amp Bridge Rectifier, suitable IIThis display consists of 35 L.E.D.'s (light BankAenrdm ra - Mastercharge. $10.00 minorimum No C.0.0 's for all amplifiers $ 2.00 emitting diodes) arranged in a 5 e 7 please. matrix. Numbers and letters of the alphabet Complete kit for 100 watt RMS stereo amplifier $10.00 can be formed by lighting the appropriate (200 watt music) including two 50-watt Sanken WsAlttsrtLs MINIMUM hybrids, all parts, instructions, and nice 1/16" segments, i.e. from our 2513 character CHARGE thick, black anodized and punched chassis $88.00 generator Rom. One 2513 can be used to I®. Same for 50 watt RMS stereo amplifier, includes drive up to 64 displays by time sharing. In two 25 watt Sankens, etc 558.00 14 Pin Dip Package. B.& F. ENTERPRISES Same for 20 watt RMS stereo, includes two 10 watt 64 Character 5 x 7 LED Display $ 9.75 Phone 16171 5322323 Sankens, etc. $30.00 2513 Character Generator Rom 512.00 PO Bos 44. Hathorne. Massachusetts 01937

Circle 84 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 101

www.americanradiohistory.com TRUE TRIGGERED SWEEP OSCILLOSCOPE /VECTORSCOPE technotes MODEL TO -50

DC to 10 mhz frequency response GENERAL ELECTRIC C -2/L -2 CHASSIS .02 volt sensitivity Complaints of no raster and no sound may be traced to Calibrated vertical an open circuit in resistors 28406, 2R404, or 2R407; shorted attenuator Zener diode 2Y405 (see diagram) or an open heater in the I9CG3 damper tube. Calibrated time base IF 2R406 is the troublemaker replace it with another resistor of equal value. the is Supplied with combi- If trouble in 2R404, replace a 2- nation Direct/Lo -Cap +22v 2R407 probe 30µF 1.7K 25V 22W 2Y405 5 X magnifier 5% +140V Automatic triggering 2R406 mode 2R404 100µF 150V 212, 10W OR 5W 5" flat face tube One Year Warranty 312, 15W edge -lit graticule +150v Made in U.S.A. 33950 2Y404 250µF

See your distributor or write Dept. RE -2 2R411 100K 1175V LECTROTECH, INC. 500 µ F CH 5810 N Western Ave., Chicago, Illinois 60659 200V 2Y404 L +280V Circle 85 on reader. service card 2Y403 350µF 100µF T350V T 300V TRANSFORMERS FOR ALL SEMICONDUCTOR PROJECTS .047 22 volts, 0.5 amp. 2 "x1%5 "x1'YS" 1.75 ea. 4/6.00 NO.J9451 48 volts ct, 0.5 amp. & 5.5 volts, 0.5 amp. 2'/. "x214"x2" 2.50 ea. 4/9.00 NO.J9450 T 12 volt ct, 4.0 amp. & NIXIE winding, 170 volts, 150 ma. 255 "x3 "x2% ". 3.50 ea. 4/13.00 NO.J9449 ohm, 10-watt original component with a 2 -ohm, I5 -watt unit 16 volts, 3 amps. & 30 volts, 1.0 amp. & NIXIE winding, (part EPI4X9). Replace the 3 -ohm, I5 -watt resistor used in 150 volts, 100 ma. 3 3/8 "x2 7 /8 "x2'rS" 3.00 ea. NO.J9254 late production with a 3 -ohm, 22 -watt unit (part EP 14X24). 34 volts ct, 5.0 amp. & 5 volts, 1.5 amp. 35. "x3% "x255 ". 5 lbs. 5 lbs. 4.75 ea. 2/9.00 NO.J9448 If the Zener diode is shorted or has a low resistance. there is no 22 -volt B +; the 22HU5 horizontal output tube NEW FAIRCHILD TTL, DTL, MSI IC BOARDS runs hot and the breaker trips. -G -E Troubleshooting Guide

SYLVANIA D -12 CHASSIS Overbright picture and blooming may be a tough -dog complaint on this chassis. This trouble has been traced to R428, the horizontal oscillator plate resistor. This resistor overheats and its value drops from 18,000 to around 9,000 ohms. Replacing it with a 1-watt resistor eliminates the complaint. -GTE Sylvania Service Notebook

New boards, with 15 to 20 marked Fairchild TTL,DTL,MSI DIP ICs. 2.75 ea. 2/5.00 3/7.00 NO.J5054 MAGNAVOX T979 COLOR CHASSIS Intermittently a bright horizontal bar moves vertically through the bottom one -third of the screen. Vertical jitter GRADE CAPACITORS (NEW) COMPUTER may also be present. Some cases can be corrected by tap- 40,000 MFD. 10 volts 1.25 ea. 6/7.00 NO.F2026 ping or moving certain parts on the "D" panel. 70,000 MF D. 10 volts 1.75 ea. 6/9.00 NO.F2118 32,000 MFD. 40 volts 2.00 ea. 6/11.00 NO.J2210 Investigation shows that this condition may be caused 3,750 MFD. 75 volts 1.75 ea. 6/9.00 NO.J2116 by a contaminate, such as solder flux, on the "D" panel plug -in socket pins -on pins 5, 6 and 7 in particular. If you encounter this condition, both the male pins on the chassis Include sufficient postage. excess will be refunded. Send for new 48 page catalog loaded with other items. Minimum order $3.00 and the female connectors on the "D" panel should be cleaned with an approved cleaner, which will not react with the PC board or adjacent components. The inside of DELTA ELECTRONICS CO. the female connectors should be cleaned using an appli- BOX 1, LYNN, MASSACHUSETTS 01903 cator such as a Phone (617) 388 -4705 toothpick and then thoroughly dried. -Mag- navox Service News Letter R -E Circle «t(, on reader service card 102 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com Li IJ 12 3 0,-4S Jn I

NEW FROM ARIES! GIANT 2Y2" NUMERAL 50 MHz DIGITAL COUNTER ULTRA LOW COST DIGITAL CLOCK "NIXIE" CLOCK KIT LABORATORY SPECIFICATIONS (STANDARD TIME CHRONOMETER) New! For factories, offices, and commercial establish- AT A BUDGET PRICE! ments, and those people who like large displays. Aries /BF has sold over 12,000 digital clocks, to the We feel the most important thing about building a kit appear as a bright continuous line which best of our knowledge more that the combined output characters is saving money. There are a lot of other advantages of can be read from distances as great as 150 feet. All of all other manufacturers. Because of our huge course . maintainability, use of standard paru, employs new purchasing power, and the engineering background drive circuits are solid state, and unit complete documentation, and the experience and fun custom LSI clock chip. Indicates hour, minutes, and gained, we can offer the features listed below. Com- of building it, but the overriding consideration is seconds. May be wired for 24 hour or 12 hour pare with any other manufacturer and see if they can economy. This kit costs less than half that of the offer all these features: operation with a simple jumper change. Kit offered lowest priced competitive unit on the market. complete with or without case for custom installa- years Decorator solid walnut case. A Striking addition to tions. Parts include P.C. board, sockets, solid state The Aries 50 MHz counter is designed for of even the most luxurious living room. Our sketches components, hardware, resistors, caps, viewing filter, maintenance free service. MSI integrated circuitry, just don't do it justice. OTC. cold cathode display tubes and conservatively rated Superb accuracy, seconds per month transformen mean low temperature rise. All displays Sh. W t. 15 lbs. Choice of 50 or 60 Hz operation, 12 or 24 hour and I -C.'s are in sockets for easy maintainability. The display in hours, minutes, seconds. GNNC /C With Case $98.50 master oscillator is a 1.0 MHz crystal in a custom BCD outputs, for auxiliary readouts etc. GNNC Without Case $84.50 designed cosmos oscillator circuit, having a stability of Excellent beginners kit, elaborate step by step 3 PPM. Accuracy is 0.005% worst case, 0.0002% or instructions debugged by trial construction by VIEW HOLOGRAMS! PERFORM better when adjusted to WWV with a communications experimenters who have never built a kit before. receiver. A front panel selects a timing interval of 1.0 Only a soldering iron, wire snip and screwdriver OTHER EXCITING EXPERIMENTS seconds, 0.1 seconds or 10 milliseconds. A variable needed. Guaranteed suttee (maximum repair LASER KIT! monostable multivibrator holds the count on the front charge $10.00) panel for a period of a fraction of a second to infinity. Now available only For use in the period mode, the 1.0 MHz oscillator is Low-cost Digital Clock Kit $47.50 from Aries! Brand new connected to the main counting chain and gated by Hughes "Hip Pocket" the input signal. type tube, and Aries OPTIONS Assembly time for the kit is approx. 10 hours. The power supply kit, plus semiconductor complement is (1) 7400, (11 7408, (1) 00 - Standard readouts, GE florescent standard complete experimental 7442, 110) 7490 ,(2)74122,16)74141,(1)74193,(1) unless otherwise specified. Cool blue green color, accessories. These tubes 74196, (1) 74511, (1) CD 4007AE, (1) LM309, (6) best for decor of living rooms, bedrooms etc., this are completely guaran- is the unit that draws Oh's and Ah's. Diodes, and (1) Transistor. If you always wanted a teed by Aries and laboratory quality counter, but could never justify the 01 - Burroughs 85750 nixie tube readout instead Hughes, but are available at this bargain price because price, here is your chance. of GE hot orange color. Looks at home in a lab. their power output is slightly below Hughes standard. No extra charge. Because of this fortunate purchase, you can purchase ' 50 MHz Counter Kit, Complete with Crystal Time 02 - Man 1 L.E.D. readouts. Intense red, the complete experimental kit for less than the price Base and Case - Postpaid in USA $125.50 monochromatic light output, laboratory environ- of the tube alone. The Hughes specification for this ment type display. Add $22.50 additional for this tube is 1.4 milliwatts output power when new, so that display. minimum power specification of 1 milliwatt can be 03 - Quartz crystal time standard. In most met throughout life of tube. Our specification is initial environments standard line operated units will give power between 0.9 and 1.4 milliwatts, guaranteed not accuracy of a second a month. If you live in an to go below 0.5 milliwatt during the guarantee period area where line frequency is poor, this will give you (6 months continuous operation!) Our kit includes an independent time base of .0005% accuracy experimental accessories such as lenses, pinholes, when properly trimmed. Add $22.50 for this mirrors and a hologram to perform hundreds of crystal time base. fascinating experiments. Holograms viewing is easily Special - National MM5311 clock chip and demonstrated with this kit, hologram making is readouts only, with instructions for do it yourself possible, but is recommended only for advanced clock projects. Specify GE florescent or Burroughs experimenters. 85750 nixie tubes as readouts $24.50 Laser Experimental Kit 5119.00

TEXAS INSTRUMENTS "ELECTRONIC SLIDE RULE" CALCULATOR This brand new calcula- POCKET CALCULATOR tor from T.I. promises We expected a favorable reaction to our calculator, to revolutionize engi- however, we were overwhelmed when we received neering calculations! orders for hundredds at a time. The reaction of our Use scientific notation, customers was that they felt this was the most i.e., 4235.7867 is ex- advanced pocket calculator on the market, and priced pressed as 4.2357867 x so low, they could assemble and market it at a profit. 103. Does squares, The features that make this so exciting are: square roots, recipro- So compact it fits in a shirt pocket (3 -13/16 x cals, adds, subtracts, 4 -5/8 x 1 -1/4). multiplies, divides. If AIRCRAFT /AUTO /BOAT QUARTZ Performs every function you would expect in a you have been looking CRYSTAL CHRONOMETER desk calculator, and then some, multiplies, divides, at electronic slide rules Revolutionary!, was the reaction of our customers adds, subtracts and gives true credit balance. you know what a phenomenal deal this is. By the way when they saw our latest kit. Measuring only 2 %" x Includes constant and chain operation, full floating HP's this is direct entry as opposed to indirect entry. 2%" x 2 -3/8 ", and accurate to 10 seconds a month, this decimal, suppressed trailing zeroes, and automatic T.I. "Electronic Slide Rule" $149.00 chronometer promises to entirely replace mechanical single entry squaring. clocks in cars, boats and airplanes. Powered by self contained AA batteries with up to Fits into a standard 2 %" instrument panel cutout. The six hours operation (Nicad batteries with charger displays are bright L.E.D. displays that should last a option, up to five hours per charge). \1'1 lifetime. Setting controls are recessed and operate Calculations performed by a single 40 pin LSI /YT' i g3 from a pointed object such as a pencil point or paper (large scale integration) chip. Displays are 8 digit \ clip, in order to keep non. authorized hands off. The LED's (light emitting diodes) and overflow and minus signs are also LED's. E fEB clock should only have to be reset at very great intervals, or in the event of power loss (i.e. replacing As a student, engineer, salesman, accountant or battery in car). The clock is wried so that the tinting anyone who would like fast accurate answers, this circuits are always running, but the displays are only calculator fills the bill, and at a price that lit when the ignition is on, resulting in negligeble unquestionably makes this the lowest price high FUNCTION GENERATOR KIT power drain. The low price is only possible because of quality calculator available. a new one chip MOS clock circuit, developed for Pocket Calculator Kit $75.00 IMPOSSIBLE? quartz crystal wristwatches. Pocket Calculator Completed $99.00 A $700.00 function generator for $99.00? But true! Operates from 10-14 Volts D.C. An accessory unit NiCad Batteries & Charger $17.50 The new, low-cost EXAR 205 monolithic waveform which mounts on the back adapts the unit 59 20 -28 Batteries & Charger Completed $25.00 generator makes this price possible. Our kit uses two volts for twin engine aircraft and larger boats using 24 generator circuits - one is a carrier generator, and Volts ignition. Know how disgusted you are with the Check Enclosed Master Charge BankAmencard produces sine, triangle, square, sawtooth, ramp and usual car clock? Order this fine unit now for rallying, pulse waveforms. The second is a modulation genera- sports events, navigation, or just to have a fine tor, for amplitude or frequency modulation of the chronometer that will give you a lifetime of superbly Charge No 11 I output waveforms. Output frequency range is from 20 accurate time. Hz to 1.5 megaHertz. Modulation is switch- selectable Quartz Chronometer, Kit Form $69.50 ARIES, Inc. for internal AM, internal FM, or external modulation. Quartz Chronometer, Wired $99.50 119 Foster Street, Peabody, Mass. 01960 Model AR -620K Function Generator ... $99.00 24 Volt Adapter $10.00 (617) 532 -0450

Circle 87 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 103

www.americanradiohistory.com CIRCUITS DISCOUNT ELECTRONIC (continued front page 99) purchased or selected on a bridge PRICES TECHNICIANS! from 5% or IO% stock. The other standard capacitors can be selected to TEST near -equal precision from - Raise your professional standing service grade capacitors. and prepare for promotion! Win Simply set the range switch to your diploma in the EQUIPMENT 1000 pF range, connect the 1000 -pF ENGINEERING precision capacitor to the TEST termi- MATHEMATICS nals and adjust the pot so the meter reads one -tenth fullscale or IO on a from the Indiana Home 100 ttA scale. Now, without touching Study Institute the pot setting, select and substitute a We are proud to announce two great .01 -µF capacitor that will cause the new courses in Engineering Mathematics for the electronic industry. meter to read exactly fullscale. Thus. These unusual courses are the result of many years of study and thought by the selected capacitors can be used to se- President of Indiana Home Study, who lect other range capacitors with ten has personally lectured in the classroom to thousands of men, from all walks of times and one -tenth their value. life, on mathematics, and electrical and electronic engineering. You will have to see the lessons to ap- STARTING NEGATIVE - preciate them! Shure and Electro -Voice NOW you can master engineering RESISTANCE DEVICES Microphones mathematics and actually enjoy doing it! A bit of inductance (L) in series WE ARE THIS SURE: you sign no contracts -you order your lessons on a and a little capacitance (C) in shunt, money -back guarantee. In plain language, ij you aren't satis- will start negative- resistance devices fied you don't pay, and there are no strings attached. whose firing voltage is a little higher Write today for more information and than the supply voltage. For example. your outline of courses. You have nothing to lose, and every- neon lamps that work on 115 volts ac Catalog & Prices on Request thing to gain! but not on 115 volts dc. In the circuit shown, the theo- Radio Supply The INDIANA FORDHAM Company, Inc. retical peak voltage is 2E when we HOME STUDY INSTITUTE 558 Morris Ave. disregard the resistance in inductor L. Bronx, N.Y. Tel: (212) 585 -0330 IlCIl Dept. RE -2, P.O. Box 1189, Panama City, Fla. 32401 Thus type NE -2 neon lamps connected this way will light on 90 volts or less DISTRIBUTORS OF ELECTRONIC SUPPLIES ircle 00 on reader .service and are handy as low -drain pilot carel Circle 88 on reader service card lamps. INTERNATIONAL ELECTRONICS HARD- TO-FIND V-1.2E WHEN S1 CLOSED UNLIMITED ENTERS THE MAIL ORDER BUSINESS WITH TOOLS "SPRING SPECIALS" L FOR ELECTRONICS AND FINE MECHANICS 7400 7401 7402 7403 S 7404 7405 7408 7410 EACH $.20 7420 7430 7440 7460 it nh& LOW POWER DEVICES !d ry. r. .7/ 74100 74L02 74L04 ' , v , . 74L20 74L30 74L51 EACH $.40 ENGINEER TOOL KITS EWIVEI-NEAD PLIERS 10110UE SCRAWDRIVRf OTHER 74L71 74L72 74L73 LOADS 7441 7442 EA. $ .90 7489 EA. $3.25 7447 7448 EA. .90 7490 EA. .69 7473 EA. .40 7491 EA. 1.05 7474 EA. .30 7495 EA. .85 , 7475 EA. .69 74154 EA. 1.75 CORDLESS TINT DRILL DE- EOLOERNO TOOLS ERRAL ELIDE RIA4 7483 EA. 1.20 74165 EA. 1.75 7486 EA. .45 74181 EA. 4.50 V » E WHEN 52 IS OPENED AFTER CLOSING LINEAR SPECIALS course, you add a switch Of if LM 309K (T03) 5 volt reg. EA. $1.95 with a limiting resistor to temporarily LM 309H (T05) 5 volt reg. EA. .95 MP Ee- ,wRrR/o 709 Op. AM. 35¢ or 10 For $3.00 RETAINING RING RIERS ATTACHE TOOL CAME STRIPPERS short C -as is done when starting fluo- . 741 Op. AM. 45¢ 10 For $4.00 rescent lights -you get a peak voltage CALCULATOR CHIP , many times E when you open this aill' 5001 LSI Calculator Chip switch. In this case C may be only One Chip Calculator Each $9.95 stray capacitance. -A. H. Taylor R -E with complete info. TNERMAl STR WE RS DRIVER WTI ULTRASONIC SOIDERNO LED DISPLAY 7 Segment (MANI) Display Each $3.95 ::.j-T- 8223 Field Programable Rom 256 Bit with 32 8 -bit words EXTRA SPECIAL EACH $7.95 .OIMCKDRAW ANT-WICK TWNLRt CENTRI. GAL STRMER Min. order $4.00 Prepaid in U.S. 7p0(S Orders Filled Within 3 Days After Receipt. (W , -*/ INTERNATIONAL ELECTRONICS Includes 72 pages of hard -to -find tools \0 I _ used by electronic technicians, instru- \ UNLIMITED ment mechanics, engineers, scientists. Over 1700 items listed. Write today. - - -- P.O. BOX 2238 Q DENSEST TOOL6 ana AL L OYES "There's no use talking into the intercom WALNUT CREEK, CALIF. 94595 ARIZONA $5015 4117 N. 44TH STREET, PHOENIX, . . . that's what we came to fix." Circle 89 on reader service curd Circle 9/ On reader service card 104 RADIO- ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com DEE market 5IT! CATALOG Now Get

MUSIC ONLY FM Programs Convert ANY FM TUNER to receive uninter- rupted commercial free music being broadcast by many stations.

TUBES Kit Only WANTED New three transistor plus "Phase locked loop" IC circuit gives you $1qs0 BUYING baseball cards issued with gum, to- RADIO and TV tubes 36¢ each. One year perfect reception. No tuned circuits, or critical adjustments. The With Squelch bacco, etc. before 1960. Send cards for ap- guaranteed. Plus many unusual electronic bar- 175" s 4" circuit board is pow- $1950 -E praisal and offer at my expense. RUSSELL gains. Free catalog. CORNELL 4217 Univer- ered from the tuner supply. *9 WALTERS, 622 E. Sunset Drive, No Muske- sity, San Diego, Calif. 92105 to 12 Volts DC @lo Ma. required. Wired & Tested gon, Mich. 49445 52500 SAVE money on parts and transmitting- receiv- Free list of FM stations with SCA With Squelch QUICK cash . . for electronic equipment ing tubes, foreign- domestic. Send 25C for Gi- authorizations included (List alone components, unused tubes. Send list now! ant Catalog. Refunded first order. UNITED RA- $ .251 $2995 BARRY, 512 Broadway, New York, N.Y. 10012. DIO COMPANY, 56-R Ferry Street, Newark, Bank Aenericard Plus Postage 5 N.J. 07105 insurance. 212 Walker -7000 Or and Master Charge THOUSANDS Welcomed SOLD Independent News Company, Inc. Is pleased to announce a Retail Display Plan which Includes Ra- dio-Electronics as part of a group of magazines available for the earning of a Display Allowance. SOUTHWEST TECHNICAL To obtain details and a copy of the formal contract please write to Marketing Department, Independent News PRODUCTS CORPORATION Co., Inc., 909 Third Avenue, New York 10022 (Attention Mr. Randy Ardissone). Under the Retail Display Plan in consideration of your acceptance and fulfillment of the terms of formal contract to be sent to you upon request you will BOX 32040 R SAN ANTONIO, TEXAS 78284 receive a Display Allowance of 10% of the cover price per copy of each magazine in the group sold by you. This plan will become effective with all issues of the magazine group delivered to you subsequent to the date your written acceptance is received and accepted by our Company. Circle I Ui ori reader service cart!

GIANT B -7971 NIXIES (2) with 2 sockets and driver board containing hi voltage transistors. Complete CLASSIFIED COMMERCIAL RATE (for firms or individuals offering commercial products or ser- plug -in board as removed from operational equipment. Schematics included. Unbelievable vices). $1.00 per word . . . minimum 10 words. but true just $2.50 for the complete NONCOMMERCIAL RATE (for individuals who want to buy or sell personal items) 70e per word ... package. #72S -10 $2.50 . no minimum. FIRST WORD and NAME set in bold caps at no extra charge. Additional bold face at 10e per word. Payment must accompany all ads except those placed by accredited advertising agencies. 10% discount on 12 consecutive insertions, if paid in advance. Misleading or objectionable ads not accepted. Copy for April issue must reach us before Feb. 1. .:,.-:lTiiiR !Iki,r + 1 i CLASSIFIED ADVERTISING ORDER FORM IAiiA19t

1 2 3 4 5 ALPHA- NUMERIC keyboard removed from unused IBM Selectric machines. Bargain price at only $8.00 6 7 8 9 10

11 12 13 14 15 ñ_ a_ e e t 16 17 18 19 20

11l1i1 ir I 21 22 23 24 25 15$ IC BONANZA 26 27 28 29 30 Brand new DTL dual inline (DIP) package, factory marked ceramic type. The price is too good to be true. Fully guaranteed and with specs. 930 Dual 4 input NAND gate similar to 7420 31 32 33 34 35 931 Clocked flip flop " 74110 932 Dual 4 input Expand Buff " 7440 (( @ .70 Non -Commercial Rates ll _$_ 933 Dual 4 input expander " 7460 No. of Words I @ $1.00 Commercial Rate I 936 Hex Inverter No. of Words in bold caps NAMF " 7405 945 1K Flip Flop " 74110 @ .10 =$- 946 Quad 2 input gate " 7400 ADDRESS 962 Triple 3 input gate 7410 Total Enclosed $ 150 each. Buy $100 worth and deduct 10% Payment must ac- CITY STATF 71P_ Insert time(s) company order un- 24 hour delivery guaranteed. less placed SIGNATURF Please add postage for above. through accred - Starting with issue ited advertising MAIL TO: RADIO- ELECTRONICS, CLASSIFIED AD DEPT., JOHN MESHNA JR. agency 28 200 PARK AVE. SOUTH, NEW YORK, N.Y. 10003 PO Box 62, E. LYNN, MASS. 01904

Circle 102 on reader service card FEBRUARY 1973 RADIO -ELECTRONICS 105

www.americanradiohistory.com TUBES -IEC 70% disc. 5 FREE with ea 50. 50W RMS / 852 AUDIO AMPLIFIER MOD- SENCORE, EICO, MALLORY, HEP, SHURE. ULES. IM and THD 0.5 %. Frequency Response ADVERTISING INDEX Also cartridges, needles lowest prices. Full 20HZ - 20KHZ ±1.0 db. SN ratio 85 db. 1 x RADIO -ELECTRONICS does not assume guarantee. M & K ELEC. DIST., 135 -33 North- 1'h ". Model A-501. Guaranteed. $21.95 ppd. responsibility for any errors which may ern Blvd., NYC 11354 D. GRAHAM R.F.D. 1, Box 166, Greenville, appear in the index below. N.H. 03048 RECEIVING & industrial tubes, transistors. All READER SERVICE CARD NO. brands -Biggest discounts. Technicians, hob- SHIFT REGISTER 200 BITS TTL COMPAT. PAGE byists, experimenters-Request free giant $2.25 @5/$10.00, FREE 4 PGS. DATA, AND Amperex 2 catalog and save! ZALYTRON, 469 Jericho APPLICATION NOTES W /ORDER. DREAGER, 87 Aries, Inc. 103 Turnpike, Mineola, N.Y. 11501 385E Mosholu Pky No., Bronx N.Y. 10467 Bell & Howell Schools 28 -31 84 B.F. Enterprises 101 11 B Dynascan PRINTED Circuits -Free pricing guide deter- & K, Division of Corp. 23 77 Brooks Radio & TV Corp. 96 -97 FOR SALE mines costs for any quantity. BLAKESLEY 78 Castle TV Tuner Service, Inc 98 ELECTRONICS, Box 686B, Syracuse, Ind. 14 Channel Master 25 1973 HOBBY ELECTRONICS DIRECTORY. 46567. 22 Cleveland Institute of Electronics 74-77 Hundreds of companies, products and ser- 94 Conway Electronics Enterprises vices. Parts, test equipment, surplus, plans, IC MANUAL LISTING MORE THAN 500 COM- Ltd. Cover IV CREI, Division of the McGraw -Hill kits, and more. $1.50, NEWCAL ENTER- PIN MON DIGITAL IC's WITH CONNECTION Continuing Education Co 64-67 PRISES, Box -C, El 323 Segundo, Calif DIAGRAMS, $2.75. ELECTRONETICS, Box 10 Crown International 22 90245 278, Cranbury, N.J. 08512 86 Delta Electronics 102 81 Delta Products, Inc. 99 13 Dictaphone Corp. 24 92 Edmund Scientific Co. 110 SCHOTTKY IC's TRANSISTOR SPECIALS 65 EEP Corp. 87 73 Electronic Distributors, Inc. 91 74S00- .99 74S64- .99 2N965 PNP 6E T0.18 .15W 7V .1A300MHZ 40Hte 5/$1.00 76 EICO, Electronics Instrument Co 97 .99 74573 -1.95 2N1605 NPN 6E TO.5 .15W 24V lA 14MHZ 74503- 125 5/$1.00 EMC, Electronic Measurements Corp 98 2N2360 PNP 6E TO-33 .06W 20V .05A 980 32 $.50 74SO4- .99 74574 -1.75 8 Electro-Voice, Inc. 16 2N5324 PNP 6E TO-3 60W 250V 104 20 35 $1.50 74S05- .99 745107 -1.95 67 Enterprise Development 2N1015D NPN SI T0.82 150W 200V 7.5A .025 10 $1.45 Corp. 88 74508- .99 745108 -1.95 2N2015 NPN SI TO-36 150W 50V 104 .012 26 $.90 17 ES Enterprises 32 74510- .99 74S112 -1.95 2N3584 NPN SI TO-66 35W 250V 2A 10 100 $1.50 83 Esse Radio Co. 100 2N3055 NPN SI TO-3 115W 100V 63 74S11- .99 74S113 -1.95 15A .01 50 $1.00 John Fluke Mfg. Co., Inc 85 2N3772 NPN SI TO.3 150W 60V 30A .2 30 $1.25 90 Fordham Radio Supply Co. 104 74520- .99 745114-1.95 2N5296 NPN SI TO-220 36W 40V 4A .8 60 $.50 7 Grantham School of"Engineering 15 74140- .99 2N6109 PNP SI TO-220 36W 40V 74522- .99 4A .8 60 $.55 GTE Sylvania 81 2N4898 PNP SI TO-66 25W 40V 4A 4 46 $.60 74540- .99 745153 -1.95 66 HM Electronics, Inc 87 MJ2251 NPN SI 10.66 10W 225V .5A 10 40 $.70 74551- .99 745157 -1.95 100 Heath Co. 92 -95 2 ICS School of Electronics 1 Dual ELECTRIC PRINTED CIRCUIT BOARD photo Full Wave Bridges 88 Indiana Home Study Institute 104 CELL a COMPLETE sub- 31/4" x 6" single sided paper 62 International Components Corp 84 strate circuit, with MAN -1 LED epoxy board 1/16" thick un- PRV I 2A 64 23 International photo cells, transistors I Crystal Mfg. Co 78 etched 3 boards /$1.00 5 Volt READOUTS 200 91 International Electronics Unlimited 104 and resistors, used to I .95 I 1.25 $4.50 89 Jensen Tools & Alloys 104 shut off and on light 400 11.15 I .1.50 79 Judson 7 segments 5V 8ma, 16 pin sensitive circuits $1.75 600 Research & Mfg. Co 99 11.35 11.75 69 Lafayette DIP display, 250,000 hr. 8223 field prog. ROM $8.00 Electronics 89 1101 256 bit RAM $4.00 25 Leader Instruments 80 lifetime $3.25 85 Lectrotech, Inc. 102 TANTULUM CAPACITORS LINEAR CIRCUITS 3 Mallory Distributor Products Co. 5 KIT 16 DECADE COUNTER 4.7 MFD at 20V 5 /51.00 McGraw-Hill Book Co 27 19 CONSISTING OF: 10 MFD at 20V 4/$1.00 PA234 1W audio ampl . $1.25 Micro- Instrumentation Telemetry 1 -NIXIE TUBE and SOCKET 4.7 MFD at 100V $ .50 PA264-5 Watt regulator $1.25 Systems, Inc 34 1 -7490 1 -7475 1 -7441 10 MFD at 100V $ .75 LM309K 5V lA regulator $2.25 80 National Camera Co. 99 Special priced at $5.50 200 PRV 15A full wave SE 501 Video Amp $1.00 National Radio Institute 8 -11 rectifier 5.95 531 High slew Oper amp $2.50 National Technical Schools 18 -21 Oper amp $3.95 NIXIE TUBES TTL IC SERIES 536 FET input 6 Olson Electronics 14 537 Precision 741 .25 7476- .60 $2.50 71 Oneida Electronic Mfg. Co., Inc 90 Similar to Raytheon 8754 7400- 540 70W Power driver $2.04 tubes, with socket & data 7401- .25 7480- .65 20 Perma -Power 72 2 us to 1 hour timer 7402- .25 7481 -1.25 555 $1.19 sheet $2.25 3/56.00 560 phase lock loop $3.25 18 Radio Shack 33 7403- .25 7483 -1.25 RCA Electronic Components 7486 .60 561 phase lock loop $3.25 2N3819 FET $.45 7404- .28 - 7490 565 phase lock loop $3.35 9 Semiconductors 17 TIS43 UJT 5.50 7408- .25 -1.00 7410- .25 7492 - .79 566 Function gen $3.25 61 Solid State 83 7416- .48 7493 - .79 567 Tone decoder $3.25 RCA Institutes 46-49 LSI CALCULATOR CHIP RF $1.00 7420- .25 7495 - .90 703 -IF amplifier 1 RCA Parts & Accessories Cover II A 40 pin DIP unit that adds, 7430- .25 74107- .60 Dual 709 $ .95 75 Rye Industries, lac. 96 $ .39 subtracts, multiplies and di- 7440- .25 74121- .70 709C operational Amp 68 S & A Electronics 88 a 12 74141 723 Regulator $ .75 vides. Used in digit cal- 7441 -1.30 -1.35 21 Sams & Co., Howard W 73 culator 7 segment MOS levels. 74154 -1.95 741 operational Amp $ .39 7442 -1.50 24 Sansui 79 Data sheets included. $12.50 7446 -1.50 74161 -1.79 747 Dual 741 $1.25 15 Schober 7447 -1.50 74192 -1.75 748 Adjust 741 5 .44 Organ 26 95 Sennheiser Electronic 89 ER900 TRIGGER DIODES. These 7448 -1.25 74194 -2.35 TVR 2002 high powèr 93 Shure Bros Cover biodirectional trigger diodes are one 7450- .25 8570 -1.90 723 $1.00 III 4 of the best and cheapest methods to 7460- .25 8590 -1.90 CA3065 FM /TV amp $1.35 Sprague 7 9309 trigger SCR's and triacs ..4/51.00 7472- .40 -1.95 5558 dual 741 12 Telematic 24 7473- .75 9312 -1.95 (mini -DIP) $ .88 64 Telex 86 FLY 100 Visible LED $ .65 7474- .50 9322 -1.95 65 70 Tescom, Corp. 90 GaAs IR LED S 7475 -1.00 Silicon Control Rectifiers MRD 14B 72 Tri-Star Corp 91 photo 14 Pin DIP sockets 3 /51.00

darlingtons .65 1 5 Tuner Service Corp 13 S 20A 1 70A 16 Pin DIP scokets 60 PRV 6A 110A 1 3/4" reed switch 6/51.00 50 .25 .32 74 TV Tech Aids 91 1N4886 25 -40W TEN TURN TRIM POTS 82 Vero Electronics, Inc. 100 Power varactor $4.95 500ohm, 10K, 20K, 25K 100 .30 .45 1.00 3.50 50K 5 75 3/$2.00 MARKET CENTER.... _ .... 105 -109 1.25 6.50 TRIACS Silicon Power Rectifiers 200 .50 .75 ATV Research Corp 107 300 .60 .90 1.50 Automatic Service Co. 107 PRY IA 10A 15A 20A PRY I 114 3A 112A 50A Barta -DRA 107 100 .06 .09 400 .70 1.10 1.75 9.50 100 .30 .80 .85 1.05 I .24 .90 Command Productions 107 500 .80 1.25 2.00 200 .65 .85 1.25 1.45 200 .07 .12 1 .20 1.25 104 Digi-Key 107 600 .90 1.40 2.25 11.00 Fair Radio Sales 109 300 .75 1.10 1.45 1.65 400 .09 .16 I .35 1.50 Hunnicutt Digital Elec. 109 600 1.80 terms: FOB Cambridge, Mass. .11 .20 1 400 .90 1.35 1.75 1.90 .50 Send check or Money Order. Include 106 JTM Associates 109 500 1.20 1.50 2.50 2.20 800 .15 .281.70 2.30 Postage. Average Wt. per package Lakeside Industries 107 3/2 lb. No. C.O.D.'s. Minimum Order Lesco Electronics 107 *Press fit 1000 .20 .351.90 2.75 $3.00 102 Meshna Electronics, John Jr 105 Send for our fall catalog featuring Transistors and Rectifiers; 325 Elm St, Cambridge, Mass. 105 Polypaks 108 -109 103 Solid State Sales 106 101 Southwest Technical Products 105 Startronics 109 United Sales 109 Yeats Appliance Dolly Sales Co. 109 Tel. (617) 547.4005 SCHOOL DIRECTORY...... _ 109 Valparaiso Technical Institute 109 Circle 103 on reader service card 106 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com PRINTED circuits -low cost, CIRKUT BOARDS Box 3193 Station C, Toledo, Ohio 43607 BUSINESS OPPORTUNITIES TV tuner repair, VHF or UHF $9.50 plus major PRICES parts and shipping. One year guarantee. NEW START SMALL HIGHLY PROFITABLE ELEC- CUSTOMERS SAVE $2.00 WITH THIS AD. We TRONIC PRODUCTION IN YOUR BASEMENT. IC SLASHED ship C.O.D. UNITED TUNER SERVICE, Box INVESTMENT, KNOWLEDGE UNNECESSARY. FACTORY FIRSTS 1383, 210 Gordon Pike, Bloomington, Ind. 47401 Postcard brings facts. BARTA-REI, Box 248, , a`s Walnut Creek, Calif. 94597 FREE catalog of amplifiers, inverters, burglar NATIONALLY alarms, power supplies, car accessories, etc. KNOWN (uproot IU11 I BRANDS Write: C.P.A. RADIO 2115 Norris Canyon II Road, San Ramon, Calif. 94583 PLANS & KITS SATISFACTION GUARANTEED DIGITAL TTL 220 B & K, SENCORE TEST EQUIPMENT, 7400N 220 7453N DIS- 7401N 220 7454N 220 COUNT PRICES. FREE CATALOG AND ELECTRONIC ORGAN KITS, KEYBOARDS for 7402N 220 7472N 350 PRICE SHEET. FORDHAM RADIO, 558 Morals music synthesizers and organs. Independent 7403N 220 7473N 460 420 Avenue, BRONX, N.Y. 10451 and divider tone generators, diode keyer sys- 7404N 240 7474N 7410N 220 7475N 720 tems. I. C. circuitry. Many components. 25C 7420N 220 7476N 504 CALCULATOR chip, TI MOS $65.00, Digital for catalog. OEVTRONIX ORGAN PRODUCTS, 7430N 22C 7486N 520 Clock chip $25.00, data only $1.50. D & C Dept. B, 5872 Amapola Drive, San Jose, Calif. 7440N 220 7490N 720 7492N 720 CO., Box 255, Collingswood, N.J. 08108 95129 7441N $1.20 7442N $1.15 7493N 720 7447N $1.02 7495N $1.05 RECORD telephone conversations- automati- CONVERT any television to sensitive big - 7451N 220 74107N 470 74121N 510 cally. Leave recorder unattended. ROBERT'S, screen oscilloscope. Only minor changes re- Box 49RE, Parkridge, Ill. 60068 quired. No electronic experience necessary. Il- "5% OFF TTL IC PRICES AT 100 PCS TTL ICS lustrated plans $2.00. RELCO -A25, Box MIXED. PHOTOFLASH: FT 106C, 800µF, trigger coil - 10563, Houston, Tex. 77018 $12.50. Catalog. TRANSPARK Dept. R., Car LINEAR INTEGRATED CIRCUITS lisle, Mass. 01741 709C TO -5 DIP or MINIDIP 38e 10/$3.50 SOLID STATE TO -5 or DIP 380 10/$3.50 FREE catalog lists 710C resistors, tubes, transistors, ,<1 MAD001A : 900 10/$8.25 rectifiers, TV MODULES 723C 10-5 condensers, tools, tuners, etc. etc. 741C TO -5 DIP or MINIDIP ....400 10/$3.70 HYTRON HUDSON, XL 100 GE QUASAR DURAMODULE v v v v Dept. RE 2201 Bergenline NEW EXCHANGED LIST $2.00 P.P. 748C TO -5 DIP or MINIDIP ....430 10/$3.95 Ave., Union City, N.J. 07087 ENCYCLOPEDIA OF MODULAR T.V. - PARTS LIST TROUBLE CHART 558 (DUAL 741) MINIDIP ...... 750 10/$6.75 DWGS PAYS FOR ITSELF ON FIRST CALL 513.95 POST PAID - 558 (DUAL 741) TO-5 900 10/$8.25 a utomatu S'Erbttr CO. (201)838 7077 LM309K TO -3 $2.25 5/$10.00 LOGIC Probe with LED display $20 00 post- 22 GORMLY RD., paid U.S. Order from UTI POB 252 Waldwick, BUTLER, NEW JERSEY 07405 N.J. 07463 GENERAL PURPOSE SILICON TRANSISTORS CANADIAN surplus catalog $1.00. ETCO A NEW INSTRUMENT TO USE WITH YOUR SCOPE ELECTRONICS, 4648 McGill, Montreal, Can- MULTITRACER 2N3638 PNP 200 10/$1.65 100/$15.00 ,. Use with your present Osc,hoscope to trace 2N3638A PNP 220 10/$1.80 100/$16.50 ada - - Resistors. Capacitors. Transformers, Diodes, Transistors. Deners. Tngistors. most Semicon 2N3641 NPN 230 10/$2.00 100/$17.50 ductors. IC's. etc. Also shows continuity. in 2N3643 NPN 230 10/$2.00 100/$17.50 SEMICONDUCTOR and parts circuit and goyno.go checks. Complete will catalog. J. & J. diagrams and instructions. No internal scope 2N5133 NPN 150 10/$1.25 100 /$10.00 ELECTRONICS, Box 1437, Winnipeg, Mani- %- ections. For medium or small production / - runs or for hobbyist. experihnenter, engineer, 2N5134 NPN 150 10/$1.25 100 /$10.00 toba, Canada xi" orham. 2N5137 NPN 180 10/$1.50 100/$13.65 ONLY 519.95 -CHECK OR MONEY ORDER WIRY PAY MORE? 2N5138 PNP 150 10/$1.25 100 /$10.00 PNP 100 /$10.00 ELECTRONIC ignition- various types, informa- BOX 14, LESCO ELECTRONICS, SKOKIE, ILL. 60076 2N5139 150 10/$1.25 tion 10C. ANDERSON ENGINEERING, Epsom, N.H. 03239 1 AMP SILICON SUBMINIATURE REBUILD YOUR OWN JAPANESE new products monthly! $1.00. Re- PICTURE TUBES? RECTIFIERS fundable. DEERE, P.O. Box 9308, North Holly- With Lakeside Industries precision 1N4005 600PIV 10 /$1.00 100/$7.50 equipment, you can rebuild any - 1000/$60.00 wood, CA picture Lobel - 1000PIV 7/$1.00 100/$9.95 Per complete details, send name, 1N4007 address. zip code to: mm., a 1000/$84.00 Pali `+ INVENTIONS & PATENTS LAKESIDE INDUSTRIES ILII 3520 W. Fullerton Ave. DTL INTEGRATED CIRCUITS Chicago. III. 60097 !JILL", !'hone: 312- 392 -3399 DIP PACKAGE INVENTIONS Wanted. Patented; unpatented. 930, 936, 945, 946 and 962 ....Specify number GLOBAL MARKETING, 2420 -AE 77th Ave., of each type 200 10/$1.75 100 /$16.00 Oakland, Calif. 94605 EXAM

r CC MANUAL' :. /gr,sry SILICON SIGNAL DIODES

he Original Test- answers exam manual .11 that prepares you home FCC 1N4148 (1N914 equiv.) ....20/$1.00, 100/$4.00 at for First el rCC kg, aW and Second class licenses. Includes Up- f Ca.Ayg Dated multiple choice tests and key Cp PLUS 7'7 Ir cchemati e diagrams. - "Self -Study RTL INTEGRATED CIRCUITS TO -5 Ability Test." -- ONLY: $9.95 Postpaid a' '', k aPf EPDXY PACKAGE r OMMAND PRODUCIIONS P.O. BOX 26348 - E ma IPSIPII PIPS DINSION SAN FR ANCISCO, CALIF. 94126 uL900, uL914 and uL923 Specify number of each type 5 /$1.00 100/$15.00 HIGHLY PROFITABLE ONE-MAN MOLEX IC SOCKET PINS 100 /$1.00 200/$1.80 300/$2.60 500/$4.20 ELECTRONIC FACTORY 700/$5.80 1000/$8.20 ea addn 1000/$7.50 Investment unnecessary, knowledge not required, sales handled by professionals. READOUT TUBES Ideal home business. Write today for facts! Postcard will do. Barta -DRA, Box 248, 5 Volt 7 Segment Readout Tube $2.95. Count- Walnut Creek, CA 94597. ing and Display Kit (Readout Tube +7490+ 7475 +7447) $5.25, 3 Kits for $15.00

BUILD A -SPACE-AGE- TV CAMERA!! '/2 WATT 10% RESISTORS ONLY KNOWN SOLID -STATE CAMERA IN KI T FORM, Pick Values 4$ 25/750 100/$2.50 500/$11.25 Also ara Uabla lackey assembled Neal for Also avo,Iobl i ldn,rry, ,,,shied ate N,qh Support your peNamonce socked by en yea of Free Catalog -Large Quantify Discounts-Orders lab and field wino P1Ìÿ G its ed

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Has modern LSI National ('lock Chip, and 1 -90 WATT PNP, 15A, 202612, TO -:I, silicon SI 6 -page brochure chock -full with pictorials and essy -to- STANDARD' 3 -214389 npn. silicon, $5 watts, Vice MO. aquare case SI under.tand, step-by -step instructions. This kit in COM- O 3.2141212 npn, silicon, 115 watts, Vice 60. stud cage PUTER SIMPLIFIED making do- it- yourself easy( Other CHRONOMETER O 10 -íN914 fast :much diod.s, silicon 4 nanoseconds ii features include 3 setting controls. l hour per second, 10 -214404 germanium pnp. TO -5 chrome cime Sl 1 minute per second, and hold button. Eay -to- change KR1O1 7- Segment MAN -3 Type LLD, 2 -6 AMP TRIAC 200 PRV, TO-5 St from 12 to 24 hours, 4 to 6 digits. 50 to 60 ha opera- 6 Digits S57.00 O 40 C -E MICRO MIRI RECTIFIERS, silicon, porcelain to I KV SI tion. Your choice of 4 different type readout systems: KR102 7- Segment MAN -1 Type LED, -LI LED ¡the larger 40 - RECTIFIERS ZENERS, I W. 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Sprr nhrels on request "ONLY" Tye. MINI-7 Sl í.] 5117437 .50 .44 5074151 1.13 ALPHA- NUMERIC - SN7400 5.25 SN74311 SN74S0 Floure..rrnr Nlue.t:reen 507401 .25 .55 SN74153 1.25 7 -SEG. READOUTS secret - 0. 0 5117440 .25 SN7481 1.10 SN74154 I.9S IF 3 1.30 O 507482 .88 SN7415S 1.39 SLIM7 - SN7403 .25 SN7442 1.12 5N7483 a for s6. I:reen 507404 .28 1.25 O SN741S6 1.39 /Tourv.cenn Hlue- ñ 5117443 1.21 5117486 .49 SN74157 1.25 250 feeh.t - 100 O SN7405 .27 0 SN7444 1.21 SN7489 3.50 11 N n'haraeters V i O S14741S8 1.48 Filament a 507406 .45 SN744S 1.50 SN7490 1.00 MI51.73 1.75 1.7- .340 a .S70' 1.9V C /DC 43 NIN 13 5117407 .45 SN74160 1.79 x .40 .20" AC 0 SN7446 1 SO SN7491 1.10 SN74161 1.79 SLIM.73 1. 0.371" 1.1V /DC N Pila a 5117408 .29 5117447 Ceate.Hble to 7- ..ga.W Mies IC'.. 507409 -29 0 1-SO SN7492 .7l 5074162 1.79 MIMI -7 SLIM -7 / SN7448 1.25 SN7493 .71 51474163 114 3 4e5 O-f mee.raN. MelntxN. san NM.ra m SN7410 1.79 25 SN74S0 .25 SN7494 1.10 SN74165 .0 SN7411 .25 0 SN7451 .25 .93 3.50 3 -2N2646 UNIJUNCTIONS, plastic tran.,ntorn, Texas SI Ów SN7413 8 SN74I8O 1.10 S -214107. GE, m,/.t r mmonly used pnp. germanium 75 5117453 .25 SN7494 1.10 SI h sN7416 .48 SN74S4 .26 SN74IS1 4.50 3 -3 -AMP 1000 PIS epoxy bullet. silicon rectifiera Si Ba SN7417 .45 0 51174100 1.41 SN74182 1.10 0 50 - SILICON, glass rectifiers, computer, axial lead. SI SN7420 SN7455 .25 O SN74107 .49 51174154 2.50 50 -GERMANIUM, glosa rectifiera. signal. axial lead. Si 507421 .2S SN7460 .21 SN74121 .49 Q 51174185 2.50 S- 2N170. GE, RF. germanium, npn. transistors, TO -22 . - Si 5117426 .32 SN7470 .39 51174122 ,6S 5074192 1.75 O 10- I -AMP 1000 PIV, rpnxy. submini, silicon rectifiers SI SN7472 32 51574123 .99 SN7430 .26 507473 1.75 30 -S00 MW ZENERS, axial 4, 6, 9. 10. 12V rectifiera SI SN7432 .44 5074141 1.45 SN74195 1.19 4- 2N30SS, HOBBY, 40W npn silicon transistors, TO-a .28 0 507474 39 SN74145 1.28 O Si Fectory M SN74198 2.55 5 -211155, HOBBY, 10íV pnp germanium trIn.iMtore, 10 -3 .. SI I 5117475 1.00 51474130 1.25 SN74199 2.6S 3 SO AMP SILICON RECTIFIERS. silicon, 6, 12, 24 volts Si D 5 - 2141036, TEXAS, germanium pnp, 20 watts, TO -6. w /.ink . SI "How's Your 10- 2113054 hubby. npn. TO-66. silicon, 30W. 30mc Si GIANT SALE ON gar 10 SCRS, assoried voltages, TO -S, TO -IR, T0.46 SI Taae 1-IO% MEMORIES 30 -3 -AMP RECTIFIERS. oiliron, epoxy. osenrled V. .xi11 SI os...i. For 1973" 0 8- SN7441N, hobby. BCD -to -Nixie driver IC, DIP SI NATIONAL'IC'S' O 10- LINEAR AMPS, 709. 710, 711, 741, TO-5 SI Typ. Description 0 1101 236 Blt RAM MOS 53.50 10 -709 LINEAR AMPS. 741'. tan, DIP st DM5091 Tri -Stale Quad Buffer ....51. 8w1e. 0 1103 1024 Bit RAM IBOS 5.50 DM8093 Quad Buffer w344. 2513 Ch.rseter Gee. ROM 12.50 11-HOBBY MEMORY CELLS. SN7.Ist, op to 16 -Cell, D1P . SI Tri -State .... 1.00 [101.18094 Tri -Stale Quad Buffer .... 1.00 0 7489 44 SI/ RAM TTL 3.50 10.709. 710. 711 LINEAR AMPS. brand mw flat pok 11 ROM L I DM200 4 -Bit Comparator SO 5223 Programmable 8.50 2 - 2145295 35 -WATT NPN PLASTIC TRANSISTORS, for any 640 Si l [) DM210 M Channel Switch .. . 1.00 0 5224 Programmable ROM 12.50 2 -2146109 40 -WATT PNP PLASTIC TRANSISTORS, for any 540 Si G for Checker - MM5250 1024 Bit RAM .. . 5.55 "RCA AMPS, [7 DM/1220 Parity 1.00 Io CA3000 OP TO -5 case Si Cl DM5223 Programmable ROM O.SB O 4000 Olt Cor. Mowry Pin. .. 4.18 5 -723 VOLTAGE REGULATORS, TO -6 fil [! DM5230 Binary to Octal Decoder 1.00 O 4-1000 HFE DARLINGTON transistors, TO -18 case Si C 1 0158251 Pretit Biner, Counter 1.15 1 -2N5036 HI PWR 7 This display is excellent for plastic trans 100 vreo, amp Si watts SI Li DM82S9 P Divide by 12 1 10 portable electronics. 2 -2N5294 HOBBY 35 watts. plastic powers NPN DMSS02 Some as 74107 Cl mall 2 -2146109 such u DVM's, calculator., HOBBY 40 watts, plastic power. PNP s1 Cl DM5520 Modulo Divide by 2.18 1 50 etc, Equivalent to Monsanto 5- PLASTIC 35W DM535 Tri -Stale P Counter . 1.05 O powers, op., silicon. hobby 206121 READOUTS a MAN 3A, Operates from 5V, 5- PLASTIC 35W power., pap, silicon, hobby 2N6124 DM5650 Binary Counter l 00 Bfy ii DM8800 Dual Voting. Translater 1.00 O milliamperes. with 47 2- MOS FETS, N channel 10 uHmos 3N 126, TU- I M, RCA SI ... $2.95 TOS. 107. ohm dropping r Tatar 2- IBOS FETS, DUAL BATE. N chan -, 30167 -1. TO-18, RCA ... S1 ( I DM8530 Dual Die. Line Driver .... 1.00 Same SN7445 1 45 2 -NOS FETS, DUAL DATE, N chan.. 30140 -1, TO -18, RCA Si D DM5845 u O ---- DMSB46 Same as SN7446 .... 1.5 Potter & Brumfield 4-RCA 2N3500 NPN. UNE transistors. lv -fm. TO -1M Si [) DM8580 Ili Amp. 7-Seg. Der. Driver 1.55 l n rd. e,l NATIONAL KAP RELAYS LED -PHOTO -SOLAR 'DOLLAR STRETCHERS' "OP" AMPS B.e one a - "LEDS", visible. miry - i a:tore. .,,.I koala t Tee. De.eriptlon Tai. 10% "LEDS ", infrared. Jumbo, TO -1s I [7 LM -280 17.17:: 52.99.7a - 2 Watt amplifier .51.15 - "LIEDS", visible, jumbo., red. TO- I . Si -7 LM 300 Super 723 V. egalster TOS "LED" n,hle- p.rablir recten r, RARCA SI ...] LM -301 Ni- 1.5 VAC aroT . 52 -N eerferm.,rc a,ne .49 2 o PHOTO TRANSISTOR, with darhng4,n amp biter. leas Si LM -303 Voltage renewer TOS Dl'sla VC SPOT -N PHOTO TRANSISTORS, with darlinetun amp. 265777, G): si LM -304 N.g. 1.45 o - voltage rege Nt.r TOS as PHOTO CELLS. (Taos, pan,'.ke,:3OK -70 ohms LM -303 Poo. 1.49 Excellent for "HAM" me antsnaaswitching. l.teh,ns, - sl v It ge regulater TOS rac e. etc.. and 100's of commercial or in- SOLAR CELLS. ,,un,I nil rem., nun power (,r u,l.. SI LM -307 1.45 transmit. o - 0 wp.r 741 dutrtal ses. Includ.. plastic duet -cover witb diagram SILICON SENSORS, TEXAS, í1.7M Matchntix n,M. Sl .; LM -309 .69 o - f,i Super gaie ee amp TOS rad hookup in! i1 -Dan bu.. Contacta movable LM -30914 1.98 plug-in SV 200ma V. regulator TOS 1.95 gold flashed .,(ver, stationary overly. with silver cad- suris ECONOMY $1 PARTS "DOLLAR STRETCHERS" '7 LM.305K SV V. mium 10 mari 3PDT. Coil LM -350 regulator TO3 2.25 oside movables. All contacta 30 - POWER RESISTORS, 3- to -25w. square, vitreous. agio vale Si. Dut woripaer.I driver TOS .Sa dats,I16VAC 2250 ohm., 17.6 ma 12 VDC 21 mil. AGC 1611 ohms, S...: 2./.. a 1 6/16 -. Wt. 4 Dart Ceutar Din 6 -REED SWITCHES, 2" Tong. fastest mach, switch 5l. D, LM -373 ramie.. axe ampam TOS 1.49 QO 10- MICRO REED SWITCHES, 1" long, transistor work 51. AM -FM SSS If strle TOS 3.75 m..ing. Cornu Mfg. typa arquai too. 10- TRANSISTOR SOCKETS, for pnp -npn trans. powers too .. 51. F 1 SURPRISE PAR, caps, etc. O - 525. re.istoro, transistors, SI. 'Unique Scientific Device. "hand diapo sr sitixen rri.- 60 TERMINAL STRIPS, I -to -M screw A lie lugs - 51. tal mike amplifier, trissera SCR. Need. my 3 to 6vdr. MAGIC 40- RADIO TV KNOBS, R t shapes, colore, styles Si. alarm, device. Use with x1.7 DISCS. s5mmf 0 Cuu u arn, intrusion photo S UND Tí 30 - SQUARE to .01mí, space -.AVe 51 cell, triggers SCR's, relaya. LED's. Even liber optic light 4 $1698 8 75 - PRE -FORMED DISCS, condennera, printed circuit sl. be used. With hand booklet. 10 - PHONO PLUG- AND -JACK SETS, tuners, ampli, doubles too 51. may TRIGGER" 10 - KODAK LENSES. piano ronces. concave, convex. mirror Si. eacrear boil YEN 60 TUBE SOCKETS, rer pta,It-n, plug., audio. etc. 51. - TUBE SALE L. ß LINEAR r,cr5$v MARIES 100 - PREFORMED RESISTORS, ' r watt, printed ckt S1. $2.5031 O 30 - DIPPED SILVER MICAS, pop values. silvers, too SI. Burrough B797í. 0 -to -u, A -to- Meer Aer a PARS -COILS A CHOKES, ,f. r1, tint. ose, Z. 2 high ehoracte,., 17ÚV Amps te% eNreuel 50 peaks, parasitic SI. NIXIE "t" FACTOR. TEST! r vT,fe -ADAPT ERS. TO-5, DIP., flat. handy 8 !o- 'IC' SOCKET Si. 531 HI slew rob .9 -amp TO.S S2 50 60- PRECISION RESISTORS. "n, i0, 1 2W. 1 W est val. Si. PIV 2 Amp Awe 2 60 O 60 - TUBULAR CONDENSERS, to .6mf, to Ikv, molded too Si. o S.S. 1.14 532 Micro Power 741 IAI se SUBMINIATURE IF'S, 455 krs, 3. square, transistor Si, EPDXY zoo .79 .N 533 Ml Nwar 709 ...... 2.50 - FULL WAVE 200 55 1.21 535 FEY Iapt 48 amp TO.TO.II 3.95 10 - TUBULAR ELECTROLYTICS, to 100mf, for ac /dc sas. etc. Si. 2 SO O 15 NE2 NEON BULBS, for 110vac, 100' of 61. 400 537 Preelsloo 741 TO-3 - . project. SILICON i al D 1.75 540 70W pwr driver amp TO.I ... , 2.04 30 - POLYSTYRENE COMM. finest caps made, out. values . SI. 1.55 10- WITCHES, 110vac, micro, rotary, thermal, slide, Si. 808 0 II9 O 550 Preclsia 723 voilage rag. (OIPI 1.17 BRIDGE 1000 1.75 2.25 551 Tinter 2 uSecends to 1 -how IA) 1.19 10- VOLUME CONTROLS, to Imeg, duale loo, some w /switch . Si. 21. 556 Owl 741 I .55 40 - MICRO MINI RESISTORS, S's w, 100 ohm to 1meE, 5% Si. RECTIFIERS "Le. -. 1 /l6.q 3 26 30 MOLDED CONDENSERS, upright, A soda!, to 1ml to 1KV 51. 5xo PMel leek (asAI os - Phase lock loop 3 25 SO -ONE WATT RESISTORS, 1' A 5 , AB's too, 100 to 1 met $1. Bel 10 - TRANSISTOR ELECTRO'., Smf to :IOOmf, upright too Si. LOW PRICES ON 'TRIALS' 8 662 Phase lock loop 3 25 1O- UPRIGHT TRANSISTOR ELECTRO' 5mf to 300m1 Q 553 Phase lock Ieep. (A 1 . - . 3.25 51. DIP) 60 - CERAMIC CONDENSERS, I Ommf to .04, npti s, dises .. Si. Two SCRs in one case! Most complete listing! Q S66 Functlo. geserStor IM141 2.25 - - Q 667 Tone decoder 3 25 O 40 - MICRO -MICRO -MINI CONDENSERS, to .06mí Cerafll .. $1. a ante 10 amp 15 ame 28 amp (AI BOARDS, caps, etc. RV ante 8 95 Four au multiplier 3.10 s - IBM COMPUTER tan., Ces, coil., Si. SO 0 5.22 0 5.35 S.43 5.63 5.55 O 1e - ELECTROLYTIC COND's, PP's, A tubular, 2 A 3 sect. too Si. 100 .35 .52 .64 .55 1.08 702C HI -gem, DC ante, TOS .. .44 8 6- TRIMMER POTS, 100, 500, 2K, 5K, 10K 25K Vivo, soap -final. .88 0 1.25 1.48 O 703C RF -IF, amp, 14 ckts, TO -S 1.00 60 - III-0 RESISTORS, carbon. )'e, i/r, 1, 2í 6 % ... .. 51. 0 O 1.10 1.45 1.65 709G Operational amp (A) 39 O SO - DISC CAPACITORS, I Ommf to .05 npo's, hi -Q. to BKV Si . 4000 D .52OI.lf 0 1.35 01.58 0 1.95 Q 7100 Differential amp (A) 39 O 60 - MICA CAPACITORS, to .01, to 1kV, silver too, wt SI. 500 1.25 1.38 2.11 2.26 711C Duel dig. comp (AI ... - .. 39 35 - TWO WATTERS, r nantors, carbon, metal -film. 5% asst Si. 500 1.50 1.68 - 2.61 Q 7236 valise rofuletw (A) 9S MICRO POTS w nup-in. I /SW 26k, 50k 100k. ImejS1. 7410 Fregney comesasetor 7091Aí . .41 - /knob, I a amp TO S. IO amp robs. 15 & 25 amp stud. w 100- PRINTED CIRCUIT PARTS, elentro'i, trans, etc. Si. t. O. 741CV Fregwney comp 709 (miel DIP{ 49 Li 30 - YELLOW PACKET MYLARS, assorted value. A sises Si. G 74íC , IA ) 1 23 10 POWER TO FreOw4l - TRANSISTOR SOCKETS. for -3. fut types Si. STEREO PREAMP 1 -WATT p 748747C - adj. 74íC (A) .44 O 3 -"MINIATURE" MOTORS, nha /t, :4- 12vdc, high speed ---- Si. 709-709 Dual 709C IDIP) ...... 1.00 54 - PLASTIC TRANSISTORS, TO.18, printed circuit S1. IC AUDIO 739 -739 Dual store. eraamp 1.98 Duel 730-735 O O 2-CRAMER 28 VAC, 4 rpm. 60 cy timing motor 51. U AMP 741.741 Duel 741C (A) 1 00 9- wansiste o O LOO -pc PARTS, BOURNS Dots. transistors, diode.. etc. Sl. s- tra.l.fo . (A, TO -5 or 111P dual in line pok 2-110 VAC MERCURY SWITCHES. P -fit. 1" long 1, d...".1 Choose Any la TO-111 mme. SI. "r60K M- hep.) 400K I.. Ima. 3t. I- HELICAL FLASH TUBE retrtggerable. sag. strobe, etc. far (Mens -tae. Term.: odd pontage, cod'. 25 % R5tN1 net 8 1- MICHO -MINI METER, t,y" dia., "S" meter, etc. Si. 20.20,000 me. 1.95 Westinghouse: Phone Orders: Wakefield, Mau. (617) 245 -31129 3-MINI MOTORS. ar,alyd, l', y to 12'. DC, hi -speed Si. DIP. Fairchild. 3 far 14.60 WC334. TO -6. Retaih 16 -18 Del Carmine St., Wakefield, Mua. loll Water Street) C.O.D.'S MAY BE PHONED INTEGRATED CIRCUIT SOCKETS 15C CATALOG on Fiber Optics, 'ICI', Semis, Parts PNILCO -FORD cord.,. PAt galamíesodio DYNAMIC amps. 200 ohms. 6 -ft. cord Oy Any 3 - Take 10e. BIS.an tl 1] 14 -Pin, duel ln Itne 5.43 s198 MIKE 1105 5000s, d mini mkeeplutPis- C7 16 -Pin, dust in .50 POLY PAKS 23/4 : IqL" x Ys" "palm of hand." [I TO -S. 8 or IO pin. 29 P.O. BOX 9426. LYNNFIELD.MASS. 01940

Circle 105 on reader service card 108 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com BUILD 32- FUNCTION DIGITAL COMPUTER EXCLUSIVE ECONOMY -PACKED 24 -PIN IC, 12 TRANSISTORS, COMPLETE IN- CALCULATOR CHIP -40 PIN $10.75 STRUCTIONS, $15.25. ELECTRONETICS, Box 12 DIGIT ADD - SUBTRACT MULT. - DIVIDE 278, Cranbury, N.J. 08512 COMPLETE DATA FURNISHED DOUBLE BONUS Sale MONSANTO MAN -1 7- SEGMENT LED FREE catalog. Most unusual electronic kits DISPLAY $4.00 800115 al '- ics. moon ..,..s CHOOSE Free'25 TRANSISCTIFIERSTORS IT available. Music accessories, Surf, Wind Syn- $8.00 x: thesizers, Wind Chimes, many others. PAIA 8223 FIELD PROGRAMABLE ROM ton000sc RS $' TREE 256 BIT WITH 32 8 -BIT WORDS h.nN ne Pn RNORS. SIC. . L S ELECTRONICS, Box B14359, Oklahoma City, OPTIONAL CUSTOM PROGRAMMING $5.00 BOTH FREE WITH ANY $10. ORDER Okla. 73114. \ PHILCO 11 TRANSISTOR 1101 256 BIT MOS RAM $3.90 l' AM RADIO CHASSIS ELECTRONICS ENGINEERING PHASE LOCKED LOOPS ' 565 FUNCTION GENERATOR $3.25 & INSTRUCTION 566 TONE DECODER $3.25 Mika amplifier n ampli TS 567 PHASE LOCKED LOOP $3.25 Tape amplifier J Covers to LM -309 K 5 VOLT 1 AMP REGULATOR $2.25 AC or DC 1500 Kccs Broadcast band LOGIC NEWSLETTER, design and construc- SHORT CIRCUIT PROTECTED T0 -3 One of the most versatile AM Radio and multi -purpose tion. Sample copy $1.00. LOGIC NEWS- amplifiers we have seen at Poly Paks famous "Economy" LM -308 ULTRA HIGH INPUT IMPEDANCE price. Measures only 41/2" x 3" x 2" high. With tuning LETTER, Box 252, Waldwick, N.J. 07463 capacitor, IF circuitry, loopstick, ant., volume control OP -AMP 10 MEGOHMS!! $2.95 with switch, AC and phono -mike jacks. Separate switch CAN USE WITH JUST A SINGLE 5V, SUPPLY. for changing from AM radio to amplifier. Uses either SHORTCUTS to success! Highly effective, 110V plug -in adapter (not with unit) and a 9 -volt LM -380 2 WATT AUDIO AMP. $2.25 battery power. Exceptional sensitivity and power. Feed.. profitable short courses. (75 choices). Study into 16 ohm speaker. Complete with spec sheets, di,- grams, and hookup ideas. BUY 2 FOR STEREO at home. Diploma awarded. Our 27th year. DM 8200 4 Bit Magnatude Comparitor $1.90 Free literature. CIEE -E, Box 10634, Jackson, Indicates Less Than, More Than, or Equal t 8 TRANSISTOR DM Presetable 4 Bit Counter $1.05 Miss. 39209 8281 i -, r \\..,:;', AMPLIFIER CHASSIS DM 8520 Modulo N Divider $1.90 CCgg. DM 8570 8 Bit Serial -To Par, Shift Reg. $1.90 Only $3.95 TV TUNER repairs -Complete course details. DM 8590 8 Bit Par to Serial Shift Reg. $1.90 1; 12 DM 8601 Retrig. Mono. Multivibrator $1.20 secise, cm repair tricks. Many plans. Two lessons, all Same as -above, except no AM radio DM 8880 7 Segment New Decoder Driver $2.50 z ('ompletely red! With bull, -in pe :,m.ip for $1. Refundable. FRANK BOCEK, Box 3236 mike. phono w and tape inputs. Color-coded DM 8210 8 Channel Digital Switch $1.50 wires with diagram and hookup.. l5"i,rk, ell (Enterprise), Redding, Calif. 96001 DM 8551 Tri -State 4 Bit Latch $1.10 ''9VD(' transistor battery. E.,11. t, r I.I" DM 8830 Dual Differential Line Driver $1.25 Shpg, wt. l -Ib. DM 8820 Dual Line Receiver $1.25 AC -DC CHARGER- CONVERTER - Only 51.98 AVIATION ELECTRONICS TECHNICIAN -Pre- Converts above 11- and-s- transistor chassis pare for exciting career in new field of "Avion- 7400 7401 7402, 7403, 7404, 7405, 7408 from 9VD(' to I10VAC'. Easy to hook , $,21 Use "NICAII" battery charger too , wiih ics". Train at nation's largest aeronautical 7410 7420 7430 7440 7450 7454 7460 instructions). Size: 2'x1 . , "xl ;, ". l -lb. school. Indicate if eligible G. I. Benefits. 5 IN,i "HI -FI" PM SPEAKER - Only $1.98 7441 7442 7448 7495 7496 1.00 7446 7447 1.10 5 -ounce ceramic, magnet. Twin SPARTAN AIRSCHOOL, International Airport, 7472 7474 .35 7473 7476 .40 7475 7490 7493 .70 voice, nl r 4 land 8 ohms. 7483 1.05 7486 .45 74192 7489 50cÌ 6,000 cycles. - MNW, Tulsa, Okla. 74151 74193 1.55 3.40 Slq,g, w,. if lbs. .N )} 74154 1.50 TEXAS 4 -WATT HIGH school diploma for adults. Earn State Di- AUDIO AMPLIFIER Ì LOW POWER TTL- ONE -TENTH THE CURRENT $`x95 3S9r ploma. Accepted by Civil Service, business, 74L00 Type SN76024. Good up to 70 ha. 4 W, into an . -nhv, 74L04 74L08 74L10 74L20 74L30 74L51 .40 load. High input impedance, VCC 9V to 24. 1111 p:,l. colleges. Low cost. No tedious study. Money - 74L73 74L74 .90 74L90, 74L93 2.00 with heat sink. 15 transistors, 5 diodes. back guarantee. Details: H -S PROGRAM, Suite BRAND NEW PRICES All Shipments By First Class Mail -We Pay. LOWEST l0'S 2507, 1221 Avenue of Americas, New York, u I- GENERAL vP $2.95 t N.Y. 10020 JTM ASSOCIATES 3 FOR so.us i1 ELECTRIC P. O. BOX 843 MANCHESTER, MO. 63011 3 -WATT AUDIO AMP t + Delivers 3.5 w'atta continuous. In watts nea 11

heat sinks: m size: , , " uS' , ply. High sensitivity. to' 16' "ohms._ Circle 106 on reader service card .. IT'S NEW! 12 -DIGIT a re. sae Give Happiness "CALCULATOR ON A CHIP" Sorry, can't name G.S. maker! Type 81)5001. Catalog Similar to Mostek 5012. Outperforms Texan " ` FREE 8 -digit TMS -1802. Feature.: 40 -pin DIP; not 5. 1 The United Way i 5 OF THE WORLD'S FINEST 3, but only single "calculator chip ". 12- dnot adds, igit rapacity: subtracts, multiplies, di- rP I! GOVERNMENT SURPLUS tides, fixed 'point 10, 2, 3 or 4 decimal places), . S1Sid chain operations, leading zero blanking, 7-seg- ELECTRONIC EQUIPMENT ment decoded display output, overflow lockout. and negative .sign output. Drives incandement, liw fluorescent. Nixies, and LED readouts, complete .t I,P And BETTER Than Ever t. STAR -TRONICS 1 INDUSTRIAL AND GOVERNMENT ® RADIATIONRUT SURVEY ELECTRONIC SURPLUS PARTS It PIECES FOR SCHOOLS. SHOPS. HAMS a HOBBYISTS SEND FOR OUR LATEST ALL DIFFERENT Address MONTHLY PICTURE CATALOG. NOW! \a ::or»" `l,1 Box 17127, Victoreen 7108. measures Gamma radiation from 0.1 -50 Portland, Ore. 97217 12 oentgens/hr. This surplus C -D meter is . guaran- Mail Coupon for Your FREE Copy, Dept. RE eed and comes with a complete manual of instruction., theory of operation, circuitry, detailed parts list. The 20 as meter is calibrated in entgens per hour, indi- TRANSISTOR TESTER FAIR RADIO SALES cating the presence of gamma radiation. Three multi- 1016 E. EUREKA Box 1105 LIMA, OHIO 45802 plier scalsictoree+e2;scales 100,000 10,000 meg "IN CIRCUIT" 0 matched ß -Model 85 DIGITAL CLOCK LOGIC PROBE 0.9 plus letters, $19.95 Prepaid for SN7446 or S544 r LED s". r\ Places transistor into actual cket.1e4sA/i,.° , READOUTS characters: 1/. x4/53 ". operation. Operates upon contact Clear speaker tone -no Extender visual observations to make. 1 3 , 112. Cable L] Sockets .30 ea. ìTh' Tests transistors in or out of Included the circuit. with Wired Only -549 95 Ppd. Lowest prices on COUNTING SYSTEM Easy Money back guarantee. Tester 1(11.559 95 Ppd to use.Indicates: logic Includes SN7441, SN7475, 3 for levels, pulse trains, single 9 National Wired - 5139 25 Ppd SN7490, 0 to $4.50.5 $12.00 UNITED SALES. DEPT. pulses, pulse polarity, and Nixie tube, sheets. 8690 Beautiful walnut /metal case QUALITY of logic signals. 5v BRIGHTWOOD, WASHINGTON, D.C. 20011 Only 31 "x3 's "x7 "; BCD output TTL 6 DTL systems. All metal Tape G. 1 ,2" di.. s I LARGE Sperry display- .55 "h. body. 90 day warranty. With I -2" high. Mt,nn,' t I- ALLEN BRADLEY hide. with shaft. linear yy 26 page manual only - $2.50 3 different plug -in adaptors ar..lo n -sense l,igi, 'MICRO -POTS' l YEATS Free info., these 6 other digital kits, request cat.0 B -6 "tl, Ira Ohms Master Charge, BankAmericard 6 COD orders welcome. 75 2.00 7.8 CI 23.8 2 for Si - appliance 100 2.58 10.8 00.0 tea HUNNICUTT DIGITAL ELECTRONICS,Box 9793,Pt.Worih,Tex.76107 o.kn 10ew 5 Meg dollies stocktuck kraut BushingHushing & Screwdriver types N at same lira prices. MOVE 'EM EASY "'""° Technical ALLEN BRADLEY'S Type F. ' Excellence Serewdrlter #aòL 'TRANSISTOR' POTS "di'''. dolly 05.555 Any lifir/t YEATS 1000 in Electronics. 75 25.8 2500 250 1.0K 7.58 2... On 100 500 2.50 10.014 0 50.0 2 MUa f WP a DOWN our ,mall, friendly campus the emphasis i.i n living as well sas Learning. 200 750 5.0K 20.0K 75.K S MUR DeLure Model 14 sTAms Extra- curricular social activities, student clubs. a i 1 No. tudent 539.50 operated radio station. student government, w dormi- tory and a lull sports program pro, Retallt 16 -18 Del Carmine St., Wakefield, Mass. papen roues roper, FREE illustrated bredwre help ids a world ofe own Terms: add cod's Rated: 30 In which to prepare for tomorrow. Associate Degree In Engineer- pontage, 25%. net ing Electronics. B.S. Phone Orders: Wakefield, Mass. f 617 246 -3029 C, obtainable. G.I. approved, C'.O.D.'S MAY BE PHONED IN Va Yeats Appliance Dolly Sales Co. 1301 W. FOND DU LAC AVE. POLY PAKS Lynn elri Muss. 01940 e''O4' MILWAUKEE, WIS. 53205 VALPARAISO TECHNICAL INSTITUTE Dept. C. Yellowstone Trail, Valparaiso, Indiana 46383

FEBRUARY 1973 RADIO -ELECTRONICS 109

www.americanradiohistory.com LIVE IN THE WORLD OF TOMORROW ... TODAY! NEW PRODUCTS, NEW MATERIALS, NEW IDEAS! UNUSUAL PHYAL 5-C /ONCE BUYS UNIQUE HARD-TO -FIND BARGAINS FOR FUN, STUDY OR PROFIT' TAPE -SLIDE SYNCHRONIZER 130 EXPERIMENTS IN OPTICS . .PHOTOGRAPHY KNOW YOUR ALPHA FROM THETA! Coordinate tape recordings Optixiit) Experiments Kit Learn to control your Al- of. with allde series. hook up Is a complete optical & pha- Theta brainwaves for stereo recorder to remote photography lab for 130 ex- relaxation, improved mem- control projector and TOS- citing experiments. Lets you ory, concentration. Read then record what you wish recreate the periscope, tele- electrodes. hooked to ampli- for each elide. Playback and scope, microscope, kaleido- fier, filter brainwaves sig- a4t.ti TSB AUTOMATICALLY scope, Build a 35mm reflex naling audible beep for each 7 changea slides in synch. camera with interchangeable Alpha -Theta wave passed. w/ tape. Your presentation lens system l Make, develop Wrist & finger contact pick "gives itself". Perfect for photographic film! Enjoy the up end amplify heart beat, sales meetings, lectures, & tun and fascination of having skin resistance. Reliable, "talking albums" of child's growth -a new dimension to your own optics lab. Fully illustr 112 -pg manual, 6',¢x11 ", easy -to -use trainer unit otters features comparable to vacations, parties . anywhere. clearly explains usage of this stimulating kit's 114 pre- many higher- priced models. Completely safe. Most people Stink No. 41,222EH $21.95 Ppd. cision engineered components. can learn Alpha rhythm control in 10 -12 hrs with full 6 -FT CONNECTOR CORDS 54.75 Ppd. each Stock No. 71.646EH $21.00 Ppd. instructions included. Kodak Proj. l #60.804EH) Alrequipt ( #60,805E11) Stock No. 71,606EH STOP THIEVES! ENGRAVE NOW! $120.00 Ppd. NEW ELECTRONIC CALCULATOR-$99.50 Police urge STROBE SCREWS IN ANYWHERE Terrific American you to Join -made "Operation Identification ", Self - contained Flashing value w /hlg machine capa- mark your valuables w/ sic. Strobe unit w /Edison base bilities. Add, subtract, sec. or driver's license t, easily screws into any std multiply, divide, do mixed then register calculations with pollee. socket! Great for parties, -silent answers Discourages home. business, dramatizing displays, or in milliseconds. 8 digit car burglaries. Low cost safety signal to warn of entry & readout w /16 -digit tungsten -carbide -tip 110v cap. Auto. to the indus. "hot" spots, constr. precise Electric Engraver, with con- areas. Adj. slow flash rate decimal. Also features fixed trol knob to adjust depth decimal. constant key un- & from 0 -1 flash per sec. (Does width of cut, works easily not stop action.) Not as derfloor, zero suppression, on metal, glass, minus signal for true credit balance, error correction, plastic, wood, steel, most hard surfaces. sophisticated as our other Inds 2 "Operation Identification" window stickers, 10 stroues, very & Avg. life: 5 millifn keyboard roll over memory. Solid state; modular contr., "Stop Thief" but handy economical. only 3 -ib. Year guarantee (normal labels, instructions. trashes. 120v, Bb He. Approx 5x3' die. use). Stock No. 60,971 EH Ppd. No. 78.000EH .... (61/a x 9 x 2" HI) 99.50 Ppd. $9.95 Stock No. 41,9I3EH $27.50 Ppd. REPLACEMENT BULB, No. 41,918EH $4.75 Ppd. ULTRA LOW PRESSURE SENSOR TERRIFIC BUY IN HE -NE LASERS Big surplus bargain -tiny Low price on 0.5mW Laser GET POLICE, AIRCRAFT CALLS electrical pressure switch (random mode); 0.9mm Your standard AM home or activated by only 0.02 psi beam die. (at IOM.16mm) car radio can get exciting I air or 64' or less water belles Its quality. New 2 -way police. fire, local pressure.- Single pole. nor- cold aluminum cathode tube aircraft calls, etc. from mally open- 10 ma DC con- for more life stability (hi UHF bands via Converters. tact rating. 30v AC /DC beam: 9000 -hr tube life No Interconnecting wires (usual loads require sensi- under normal cond.) Ready needed -just put solid state tive relay or solid state to plug in. turn on. Starts Converter near set. Easy control). Use as sensor...... _-, ..=?i instantly. Safe. easy for rostra Incl. Ea. Kit req. 9v holography, lnterferometry, hart (not included). PO- switch, control. counter, alignment. Metal edge guide, instrument alarm. Long life (1,000,000 opera- case, 2.8 x 3.8 x 10", 110v AC, 633nm LICE & FIRE CONVERT- wavelength, small beam divergence. KR in the 30 -50 /5111z band. tions) impervious to shock, vibration. 1" sq. polycarbonate KIT - LO BAND. Operates Stock No. 79020EH Stock No. 41,828EH $8.25 Ppd. case, 3/16' diem. barbed pressure ports. Wt -l0 grams. 0.7mW 88.50 Ppd. ORIGINAL COST $11.50. (SINGLE TEMooMODE), 0.8mm BEAM DIA. AIRCRAFT CONVERTER KIT. Operates in the 106 - Stock No. 41,623E11 Stock No. 79,024EH $99.50 Ppd. 136 MHz band. $3.95 Ppd. Ppd. FEATHERWEIGHT SLIDE -SHOW "BRAIN VOICE" Stook No. 41,827EH $8.25 TREASURE FINDER & UNDERWATER MICROPHONE BUY Best. easiest to use solid Show /Corder, with built -in state metal detector at its slide -sound synchronizer. is Listen to fish "talk" with a govt. Hydro - ' Price. U.S. made! Only 3 cassette recorder too. One this surplus unit! On -site recording! phone! Terrific burl $40 that 6" head detects penny at Unique value! Make an accurate depth of 5 ". silver controls focus, ac- dollar tivate fish finder, splash - at 8 ", bag of coins at 18". fwd &rev cycles on pool 1 Works thru dirt, sand, wood, projector. Digital counter to alarm, hear dolphins talk. index; lndivid. channel add sound to underwater water (30" deep), rock with high no loss. Detects eraseabllity; monitor switch movies. Use with both power "find" to & low impedance amplifiers, with "sound off" - project external sound loud thru spkr; record music. tape recorders. Frequency - speaker. Ready to go. One tuner narration at same time. 10 -level vol. control. AC /DC. response: 10-600011z. Work- control; all trans.; adios stem; perfect balance. Inds 300 ft. Minimum sensitivity 1000 Bz. at 9v batt, FREE Inds cable for Kodak Carouseita), patch cord (radio, hi -o). ing depth to TREASURE GUIDE To 101 Treasure Sites. earphone, depths of 60 or 300 ft. Operating temperature range: Stock No. 80,175EH 539.95 Ppd. remote mike, blank cassette, 4 "C" batt., instrs. No. 71,619EH .. (9x8r/exIr /e) (51/4 Ib.) $171.50 Ppd. o to 35 °C. Fungus and shock resistant. Includes leads .. 2 oz. NEW! ELECTRONIC DIGITAL COMPUTER KIT! ( approx. 8' long) and instrs. Cable not incl. W't. $5.00 Ppd. Solve problems. play games, FLEXIBLE IMAGE TRANSMITTER Stock No. 41,759EH predict weather with this Hi- resolution Image- trans- 1st LOW -COST VACUUM PUMP! actual working model of mitter lets you see remote, Nothing like 1tl Top-quality giant electronic brains. inaccessible lighted areas; hand -held pump produces & Amazing new fun way to thru pipes, tubes, any %" + maintains 25" of vacuum. learn all about computer opening no matter how intri- Has instant release tab, 1%" programming . . . logic, cate. Provides clear, wide diem. stainless gauge (0- decimal. binar systems, sighting. 7X magnifying 30"). 100's of uses -siphon Laws of Sets -even do your eyepiece focuses from less noxious fluids, evacuate bell own programming after com- than 1" away. Ideal for Jars and castings, clean. re- pleting simplified 116 page monitoring hazardous proc- trieve, lift eterlle objects. Instructive booklet. Includes step-by -step assembly diag. esses, surveillance instr., demonstrate Magdeburg Circuits easily changed. Readout from illuminated con- demons. fiber optics. Over 4,000 coherent glase fibers hemispheres. bleed fuel trol panel. Req. 2 "D" bait. (not incl.). Best model - (.002"). %" dia. semi -rigid gooseneck sheathing. lines. check leaks, etc. Lifts 40 lbs. with included "T-' for home, school. industry. Stook No. 60,857EH $40.00 Ppd. Lifter (2ti'e" diem. cup) -much more w /larger cup. Na. 71,434EH (II" x 121/s" s 4") $31.50 Ppd. 3" ASTRONOMICAL TELESCOPE Stock No. 71,90IEH $12.00 Ppd. No. 71.800EH (without gauge /lifter) 5.50 Ppd. See moon shots. orbits - MAIL COUPON FOR stars, phases of Venus. ASTRONOMICAL TELESCOPE KITS planets close up. 60 to 180 power. New improved, alu- Grind your own mirror for FREE minized and overcoated Jr Powerful telescopes. Kit con- GIANT diameter f /10 primary mir- tains fine annealed pyrex ror, ventilated cell. Equa- mirror blank, tool, abrasives, PJ torial mount with locks on diagonal mirror, and eye- tarieB CATALOG! both axes. Equipped with piece lenses. Instrumente 601 eyepiece and mounted you build range in value I 164 PAGES MORE THAN Barlow lens. 3x tinder tele- from $75.00 to hundreds of 4,000 UNUSUAL BARGAINS scope, hardwood tripod. Included FREE: "STAR dollars. 4'/4 diam. 3/4" thick. ['HART "; "HOW TO USE YOUR TELESCOPE ". No. 70,003EH $10.75 Ppd. Completely new 1973 edition. New items. eate- Stook Ne. 85,050EH $32.95 Ppd. Stock No. 70.004EH 6' diam. I' thick $16.95 Ppd. gonies, illustrations. Dozens of electrical and No. 80,I62EH ...DELUXE 3" $61.50 Pod, Stock No. 70.005EH .8" diem. 13/e" thick $24.50 Ppd. electromagnetic parts, accessories. Enormous soles- Stock No. 85.105EH 41/4" $99.50 FOB Stock Na. 70,006EH IM diam. l% thlek 30 Iba $44.50 FOB ' taon of Astronomical Telescopes, Unique lighting Stock No. 85,086EH 6" $239.50 FOB Stock No. 70,007EH 12'/a" diam 2'/a "thick 461bs $72.50 FO I and ecological items. Microscopes. Binoculars, Mag- MEASURE TEMPERATURE REMOTELY "FISH" WITH A MAGNET aitiers, Magnets. Lenses, Prisms. Many surplus Go treasure hunting on the I items. Electronic thermometer gives instant temperatures from bottom! Fascinating fun & inches to 1000 -ft. off. Push sometimes profitable! Tie .t EDMUND SCIENTIFIC CO. button, read one of 3 separ- line to our 5 -1b. Magnet- ate temps. (Can connect to drop it overboard to hay. I Barrington, N.J. 08007 3 plug -in probes). Reads river, lake or ocean. Troll it °F along bottom -your I Please rush Free Giant Catalog "EH" from -22 to +122 & -30 "trea- AMIN- to +50 °C. Accuracy ±1r.. sured" haul can be outboard Inds 2 solid -state waterpf motors, anchors, other metal Name probee (one w /18" cable, valuables. 5 -Ib. Magnet is one 15 -ft.). 100's of uses in war surplus- Alnico V Type home, lab, industry. Req. "9" Batt. (not Intl). Walnut -Gov't. coat $50. Lifts over 150 lbs. on land-much Address fin. cab. Instils. greater weights under water. Stock No. 71,741E51 ...(3t/ax41 /ax6%) . $40.90 Ppd. Stock No. 70,571E H $14.00 Ppd. City State Zip EXTRA I5 -FT. TEMPERATURE PROBE Stock No. 70,570EH 9 -'/a LBS $8.75 Ppd Stook No. 41.839EH $2.99 Ppd. Stock No. 85,152EH 15% LBS $33.60 F.O.B. EDMUND 300ORDER BY STOCK NUMBEREDSCORP SEND CHECK OR MONEY ORDER BLDG.MONEY -BACK GUARANTEE SCIENTIFIC CO. BARRINGTON, NEW JERSEY 08007 Circle 92 on reader service card 110 RADIO -ELECTRONICS FEBRUARY 1973

www.americanradiohistory.com Con -Con to (ongreri

Nowadays, history isn't written, it's spoken ... and verbal clarity is essential wherever people meet to discuss the issues of the day. From coast to coast, from town halls to the halls of Congress, you'll find Shure microphones in the really critical, prestigious sound reinforcement installations. Case in point: when the Illinois Constitutional Convention ( "Con- Con" -see photo above) met to create the first new state consti tution since 1870, a total of 65 Shure Unidyne !!II microphones were at hand to assure a clear, intelligible voice for each delegate. The Unidyne Ill was right for Con -Con, and there's a Shure problem -solving microphone right for every installation. Write: Shure Brothers Inc. 222 Hartrey Ave., Evanston, III. 60204 SHVIIRE=

Circle 93 on reader service card

www.americanradiohistory.com This remarkable new THE Multitest set CONWAY "MASTERANGERTM" is unique MODEL 639 in its versatility, in its sensitivity, and in its price.

100M st input resistance; accurate to 1.5 %. 72 Ranges. Floating input for absolute user safety; fully overload protected. Completely portable; battery or AC operation. Attributes such as these make the Conway "MASTERANGERTM" the new standard instrument for all electronics. Its price $150.* *(Cdn. Dollars, export price -- -local taxes and duties extra.) The Conway Masteranger solid state Model 639 is the world's most com- prehensively ranged F.E.T. Multimeter. It is the result of five years' intensive research and study to determine the most required measurement parameters and ranges for the rapid testing of AC /DC Voltages, Current, Decibel, Resistance and Voltage Levels. Its design concept employs 100% silicon solid state technology, making it applicable for the measurement of any anticipated electronic development over the next 10 years. It can also carry out its functions on all contemporary equipment, and that of earlier technologies. Like many genuine technical advances, its principle is simple enough to make the Conway Masteranger relatively inexpensive. At $150, it renders many other instruments (some much more expensive) either obsolete or unnecessary. The Masteranger 639 is amazingly accurate-plus or minus 1.5% through most of its 72 ranges. Its input resistance is high -100M0 on most voltage ranges. This, coupled with its outstanding sensitivity of 1.5mV AC or DC (full scale) and its current measuring capability from 0.15µA (150nA) (full scale) up to 150A (full scale). AC /DC (with shunt box) puts the Masteranger Multitest set in a class of its own. The instrument is supplied in a smart bridle leather carrying case with detachable shoulder and neck strap. At 2.5Kg (5.5 lbs) it is easily carried. A wide range of quality matching accessories are available. RF probe extending frequency response to 1000 MHz, current range extension to 150 Amps AC and DC in 4 ranges, HV probe, Powerline cassette, Coaxial "T ", etc. Complete information, and specification sheets, on this unique professional Multitest

set is available on request. Simply fill out the coupon below and mail to :

CONWAY ELECTRONIC ENTERPRISES LIMITED 88 -90 ARROW ROAD, WESTON, ONTARIO, CANADA Telephone (416) 742 -6631 Telex 06- 965733

Gentlemen : Please send me complete information on the Masteranger 639 solid state Multitest set.

Name : Title:

Company :

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Co. or Res. Address: State, Prov. Postal

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Circle 94 on reader service card