Portable TV Sets

Electronics WorldDECEMBER, 1964 50 CENTS DESIGN TRENDS IN RECEIVER FREQUENCY CONTROL

NEW SCR DEVELOPMENTS ELECTRONIC TIME -DELAY RELAYS

Portable TV Sets

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www.americanradiohistory.com DIRECT CRYSTAL CONTROL TO 160 mc N OW With AOC Plug -In Transistor Oscillators Portable Signal Standards Signal Generators For Receiver Alignment Band Edge Markers Frequency Markers For Oscilloscopes Quick- Change Plug -In Oscillators Accessory Cases

HIGH FREQUENCY (20 mc - 160 mc) Five transistor oscillators covering 20 mc - 160 mc. Standard 77 F calibration tolerance ±.0025 ° /o. The frequency tolerance is ±.0035 ° /o. Oscillator output is .2 volts (min) across 51 ohms. Power requirement: 9 vdc @ 10 ma. max.

OSCILLATOR OSCILLATOR OSCILLATOR CRYSTAL TEMPERATURE TEL CRYSTAL CRYSTAL CRYSTAL! TYPE RANGE TYPE -40 F to 150 F (LESS FREQUENCY PRICE PRICE

OT -24 20 -40 mc CY -7T ±.0035% $ 9.10 20 -60 mc $ 6.90 OT -46 40 -60 mc CY -7T -4-.0035% 9.10 60 -100 mc 12.00 OT -61 60 -100 mc CY -7T ±.0035% 15.00 101 -140 mc 15.00 OT -140 100 -140 mc CY -7T ±.0035% 15.00 OT -160 110 -160 mc CY -7T ±.0035% 15.00 141 -160 mc 18.00

tE NORTH LEE OKLAHOMA CITY, OKLA.

LOW FREQUENCY (70 kc - 20,000 kc) Four transistor oscillators covering 70 kc - 20,000 kc. Trimmer capacitor for zeroing crystal. When oscillator is ordered with crystal the standard will be ± .0025 ° /o. Oscillator output is 1 volt (min) across 470 ohms. Power requirement: 9 vdc @ 10 ma. max.

OSCILLATOR OSCILLATOR OSCILLATOR CRYSTAL TEMPERATURE TOL. CRYSTAL CRYSTAL (LESS CRYSTAL) TYPE "F TO 150 F FREQUENCY PRICE TYPE RANGE -40 -- PRICE

OT -1 70 -200 kc CY -13T -4-.015% $7.00 70-99 kc $22.50 100 -200 kc 15.00 200499 kc 12.50 01 -2 200 -5,000 kc CY -6T 200 -600kc +.01% 7.00 600- 5,000kc ± .0035% 7.00 500 -849 kc 22.50 850 -999 kc 15.00 12,000 kc CY -6T ±.0035% 7.00 OT -3 2,000- 1,000 -1,499 kc 9.80 500-2 999 kc 6.90 OT-4 10,000- 20,000 kc CY -6T ± .0035% j-00 3,000- 999 kc 4.90 11 000- 20,000 kc 6.90

AOC OSCILLATOR CASES Small portable cases for use with the OT series of plug -in oscillators. Prices do not include oscillators. (When oscillator and crystal are ordered with FOT -10 case a 7T F tolerance of ± .001% may be obtained at $2.00 extra per oscillator/ crystal unit. When oscillator /crystal units are ordered with FOT -20 case, a single unit can be supplied with temperature calibration over a range of 40° F to 120" F. Correction to = .0005 %. Add $25.00 to the price of FOT -20 and oscillator /crystal unit.)

FOT -20 For high accuracy calibration requirements. Includes battery and output jack, output meter circuit and battery check, as well as thermistor temperature measuring circuit. $87.50 FOT -TO Basic case with battery and FOT-10 output jack for general wider FOT-2C tolerance applications. $14.50 MT -1 Oscillator board mounting kit. Order direct from International Crystal Mfg. Co. $4.95 2 CIRCLE NO. 189 ON READER SERVICE PAGE ELECTRONICS WORLD

www.americanradiohistory.com DECEMBER 1964 Eleclroiìics \\oIi(I (.0 NTE NT'S VOL. 72, No. 6

25 New SCR Developments Donald Lancaster lieretttiv are much I''ss ecpensire, are voit spit-pro- NI olio fit tr,ttiNto.ttts, awl able to conduit in both direr-tutus.

28 Portable TV Sets Leslie Solomon

31 Capacitance Nomogram Frank D. Gross 32 Recent Developments in Electronics

34 FM- Stereo Demodulator J. W. Englund, L. Plus & H. A. Hansen llr.i ^n of u raul(11,1,-1 er(1aptrt llrll u.r, ruril,rrl,ur It-,uut.Isis. The irr nit l,- //itil , lri_h Hi,is, irnnirntitr ,nr,l nrl rrnlli,

s_ Using Hook -up Wire Joseph Fart's

THE seven portable TV sets shown on the cover are only 39 Substituting Silicon for Germanium Transistors william O. Hamlin a sample of the ever- increas- ing number of battery portables soon to be made available. Starting at top 42 Early Vacuum Tubes Paul G. Watson center, and proceeding clockwise, they include the G -E 9 -inch, Panasonic 44 Electronic Time -Delay Relays Louis E. Frenzel, Jr. 9 -inch, Realtone 6 -inch, Del - monico 41/2-inch, Sony High -Speed Electronic Printer A. W. Edwards 4E 5 -inch, Sharp 6 -inch, and the Philco 9 -inch sets. The Advances in Photosensitive Devices John R. Collins three open sets show the h ¡W/o ll: flit cliff!! l trhut,en.ihr ilf 11,1, prrlHr rrl m,rae nari typical printed -board tech- nI rrnbiaertiror, filerl HHdr th,., Hait, re.pund tnarv 1111,1 intprre niques used for ease of .,vl.itil it. I r -rrictN i ruliltrrl. I' ,r1,,, Jt .ntoller. maintenance. Except for the Delmonico, each of 52 Design Trends in Receiver Frequency Control Jim Kyle these sets must be operated 7 /te (1'011 rlerl r.Í.s pertr11111 111t4 the Hsr of milli/teed nuulnl,r(in sterne rrquirr from an external battery (not 1/Ir utmost neutral in receiver ttlairt_. I Ihr lutc.st terhnigtrt's /iii rrr ltiet.irt,: shown). Each can be oper- Hrh rrrrrrrnrl ore rle,rrilnrf. inr(ndin_ t1i_itnl lurrtin_ und frequenre' svnt/tesis. ated from the ordinary a.c. power line. (Photo: Jay 75 Organ Kit Uses Diode Switching Seymour, Burns Bros. N.Y.) Electronics World 1964 Index (Vols. 71-72)

For the Record (Editorial) W. A. Stocklin Derr I orb Iii -Ii .shoo Publisher PHILLIP T. HEFFERNAN 1 f$ EW Lab Tested Editor WM. A. STOCKLIN I hrr lirlurl I up1, lier(1rder ll,r fl-.l oir,, nr,l Technical Editor MILTON S. SNITZER 56 Service Shop of the Future John Frye .-Issoriute Editor LESLIE SOLOMON 64 Test Equipment Product Report Assuriule Editor P. B. HOEFER v Irr lir,e(r r 1, /tt-(.ur utt f,rp.r,vlur' I exter 5enrrn' 129 F11-.str'rrr, .11ultipler Grvreru(r Assistant Editor lüI'd .11(1(11,1 n154 li.I. It uttnreter MARSHA JACOBS Industrial Consultant WALTER H. BUCHSBAUM Art Editor RICHARD KELLY MONTHLY FEATURES Art and Drafting Dept. J. A. GOLANEK Coming Next Month 4Reader Service Page 15 Letters from Our Readers & TV News Adrertising .times Manager 12Radio 60 LAWRENCE SPORN New Products & Literature 79 Advertising 'eriice 11tmet er Copyright ç, 1964 by Ziff Davis Publishing Company. All rights reserved. ARDYS C. MORAN

December, 1964 3

www.americanradiohistory.com Electronics \%odd COMING was W NEXT MONTH

ELECTROLUMINESCENCE manium -alloy units are quieter than Sylvania expert covers principles of op- tubes and other transistor types for this eration, technical characteristics of this application. The design of a low -noise new (orna of display illumination, and phono preamp, using the information ob- phosphors. Both home lighting applica- tained during the tests, is also included. tions and readout and display uses in industry are covered in this article. ELECTRONIC PUMPS .4n all -electronic method of producing a MULTIPURPOSE ELECTRONIC CONTROL vacuum is described in this article. It is This 200 -watt, full -range unit provides used to keep large microwave tubes and proportional control using a small audio electron accelerators gas free and in the or 60 -cps control signal. It can be used deposition of thin films for integrated as a dimmer, as a visual indicator of circuits. stereo separation, or of high noise levels. SCR HEAT SINK DESIGN CHART What size heat sink should be used for AUTOMATIC WIRING CHECKOUT 115 -colt SCR circuits or for other semi- High -speed scanning techniques permit conductors at various powers? This arti- analysis of up to 100,000 terminations on cle provides the answers. a complete wiring assembly. During NORTRONICS these tests, the device points out circuit "CHIRP " -A NEW RADAR TECHNIQUE ANNOUNCES... wiring errors. Using a swept -frequency approach. this new radar lias greatly improved range New Line of Tape Heads! NOISE PERFORMANCE OF and target resolution over conventional For true broadcast quality and max- TRANSISTORS IN AUDIO CIRCUITS pulse methods and is also less susceptible Results of testing a large number of dif- to most of the present -day jamming imum enjoyment from your invest- ferent transistor types show that ger- techniques. ment in tape equipment, replace worn heads with new Nortronics .411 these and many more interesting and informative articles will be yours laminated core replacement heads! issue of ELECTRONICS WORLD ... on sale December 17th. Available for more than 500 popu- in the JANUARY lar tape recorders, these moder- ately priced replacement heads have ZIFF-DAVIS PUBLISHING COMPANY highly polished, all -metal faces, and B. Ziff ZIFF -DAVIS PUBLISHING COMPANY offer extended high frequency re- William Chairman of the Board (1946.1953) Editorial and Executive Offices sponse, even at slower tape speeds. One Park Avenue, New York, N.Y. 10016 Other features include deposited William Ziff 212 ORegon 9 -7200 quartz gaps and low -loss core President MIDWESTERN OFFICE Ill. 60605 W. Bradford Briggs 434 South Wabash Avenue, Chicago, structures. 312 WAbash 2 -4911 Executive Vice President Midwestern Advertising Manager, Royce Richard ALL TAPE HEADS WEAR OUT! Hershel B. Sarbin WESTERN OFFICE Check today for head wear-both Vice President and General Manager 9025 Wilshire Boulevard, Beverly Hills, Cal. 90211 Nortronics new replacement heads 213 CRestview 4 -0265 Philip Sine Western Advertising Manager, Bud Dean and "Quik -Kit" mounting hard- Treasurer ware are correctly matched to your FOREIGN ADVERTISING REPRESENTATIVE and are available from Walter S. Mills, Jr. D. A. Goodall Ltd., Empire House, recorder, Director London, E.C.1, England. MONarch 0577 your Hi -Fi Dealer, Radio -TV Serv- Circulation iceman or Camera Store! Stanley R. Greenfield Member Vice President Audit Bureau of 1,7171 Tf Or Phillip T. Heffernan HIGH FIDELITY Circulations "Musk sounds best on Tape - Tape Sounds Best with Nortronks Heads" Vice President

Radio & TV News Radio News Radio -Electronic Engineering Trademarks Reg. U.S. Pat. Off. SUBSCRIPTION SERVICE: All subscription correspondence should be addressed to Electronics World. Circu- lation Dept., Portland Place, Boulder, Colorado 80311. Please allow at least six weeks for change of address. Include your old address as well as new- enclosing it possible an address label from a recent issue. 8127Tenth Ave. N., Minneapolis, Minn.55427 EDITORIAL CONTRIBUTIONS must be accompanied by return postage and will be handled with reasonable care; however publisher assumes no responsibility for return or safety of art work, photographs. or manuscripts. is by -Davis Publishing ELECTRONICS WORLD I December, 1964. Vol. 72, No. 61 published monthly Ziff also publishess Popular Photography, for your FREE copy of NORTRONICS Company at 434 South Wabash Avenue, Chicago, Ill. 60605. (Ziff-Davis Write today Popular Electronics, HiFi /Stereo Review, Popular Boating, Car and Driver, Flying. Modern Bride, Amazing, Tape Head Replacement Guide. and Fantastic.) Subscription rates: one year United States and possessions $5.00: Canada and Pan American Union countries $5.50: all other foreign countries $6.00. Second class postage paid at Chicago, Illinois and Name at additional mailing offices. Authorized as second class mail by the Post Office Department, Ottawa. Canada Address and for payment of postage in cash. PAYMENT MAY ALSO BE REMITTED in the following foreign currencies for a one year subscription: City State Australian pounds 12/161; Belgian francs (310); Danish kroner (431: English pounds (2 4 61: French is Japanese yen 2100); Nor- I own a Model tape recorder francs (311; Dutch guilders (22); Indian rupees (311: Italian lire (3900 wegian kroner (451; Philippine pesos (25); South African rands 14.501; Swedish kronor 1331: Swiss L francs (271: West German marks (25). CIRCLE NO. 242 ON READER SERVICE PAGE 4 ELECTRONICS WORLD

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www.americanradiohistory.com ...for NATURE SLIDES LOVERS.. & SOUND c IC/Cold WM. A. STOCKLIN, EDITOR

Built -in automatic syn- YORK HI Record nature sounds. chronizer advances NEW -FI SHOW Set on auto operation. slides; coordinates them THIS years New York segment of the Visitors usually had to go into the ex- Sound starts and stops with commentary or it automatically. music. Hi -Fi Show, sponsored by the Insti- hibitor's rooms in order to hear the de- tute of High Fidelity, Inc., was a monstrations instead of being blasted at SECRET DICTATION .. . resounding success despite a slight on all sides while walking through the RECORDINGS... reduction in attendance. There were connecting halls. four display floors housing hi -fi com- In general, we heard some very good ponents of all sizes and shapes from sound at the Show this year, much of over 70 different manufacturers. Just it emanating from some fairly small - about every exhibitor whose display sized speaker systems. It seems that the room we visited seemed to be enthusi- "bookshelf" speaker has finally gotten astic not only about his own new prod- small enough to actually fit comfortably ucts but optimistic about his future sales. on a bookshelf. Several companies were For investigations, inter- Use voice operation or rogations, gathering of remote -control micro- This feeling is a natural one because showing such compact speaker systems evidence. Works unat- phone. Dictate anywhere of the tremendous growth of the hi -fi and most of them were doing an excel- tended. Voice starts and - office, home or on the component industry. In the mid- 1930's, lent job of producing really good sound stops it. road. annual sales were only about $25 mil- with a very small enclosure. lion; by last year sales had quadrupled A further trend toward diversifica- MUSIC WHEREVER YOU GO .. . to an estimated $100 million. During tion was evident this year. There were this time, while there was a general some speaker manufacturers introducing rise in most prices for goods and serv- lines of amplifiers and tuners; and there ices, component high -fidelity equipment were some amplifier companies showing prices remained fairly steady. In some their own loudspeaker systems. cases, prices for equipment of compar- Another trend was that of integration able performance were even reduced. by some of the manufacturers. A large Enjoy music at the beach, on your boat, anywhere. Play commercial tapes or your own selections from So far, the greatest market penetration number of stereo receivers, with their radio or records. has been in urban areas, and there is all -in -one tuner and amplifier combina- still room for growth and increased sales tion, were on display. Also, several corn - in the future. For example, according panics displayed complete portable, to Walter O. Stanton, president of the packaged stereo systems made up of Institute, even in urban areas only about separate components but designed to- 25 percent of homes now have a stereo gether as a single system. Some of these system installed. It is his feeling that components were of their own manufac- the remaining 75 percent represents a ture, and others were made by other major growth area in the years ahead. companies exhibiting at the Show. One feature of the Show this year was The move toward complete transis- a full -fledged Discotheque. As recreated torization of equipment continued this World's First Fully- on the second floor of the New York year. A few companies have gone so Trade Show building, this looked like far as to completely discontinue vac- Automatic Voice -Operated a typical French cafe, complete with uum -tube amplifiers and tuners. On the checkered tablecloths, soft lights, and other side were one or two manufac- Portable Tape Recorder! refreshments. The music, however, in- turers steadfastly refusing to go to solid - stead of being supplied by live musi- state equipment as vet. But the great CONCORD cians, was coming from four large hi -fi majority of companies had both tube speaker systems connected to hi -fi am- and transistor equipment on display, plifiers and phono equipment. Although with the newest models being mainly there was room for dancing, most Show solid- state. visitors took advantage of the relaxed When transistors came to hi -fi a year atmosphere to rest and refresh them- or two ago, we saw two types of equip- 330You'll find all sorts of "hands-free" uses for selves. ment. One type was very high in per- Concord's amazing portable 330 - applications Not far from Discotheque was a large formance and quality, but also fairly not possible with an ordinary recorder. You hall where semi- technical panel discus- elaborate and rather expensive. The don't even have to be there. Sound starts it; sions and lectures for the hi -fi novice second type had performance somewhat sound stops it. Just set it and forget it! The were held. The three panel discussions below that of vacuum -tube equipment 330 is packed with features: automatic slide on hi -fi amplifiers, tape recorders, and but at a more reasonable cost. This year projector advance; automatic Synctrol for home music listening, as swell as the four lec- we saw the beginning of a merger of movies; automatic self -threading too! Up to tures on hi -fi components, were well at- these two design philosophies. Prices 6 hours playing time on 5" reels; 2 speeds; VU tended, with many standees spilling out have come clown on some of the tran- meter /battery life indicator and an optional into the adjoining hallway. From the sistor equipment, but high quality has AC adaptor. See your Concord dealer right great number of questions that were been maintained. away for a demonstration. Under $200.00.* asked at these sessions, it was obvious All -in -all, the Show was highly suc- Other Models to $450.00. that there is a large and serious interest cessful. The attendance for the four - For Cnnr ois.ct'urr Of Sound in component hi -fi. day period was about 22,000. For those As far as the display rooms and equip- of -you who missed the New York Show CONCORD 330 ment were concerned, everyone had his at the beginning of October or the pre- CORPORATION new models on display. The over -all vious San Francisco Show in September, CONCORD O®ELECTRONICS Naas this you have another chance at the Los 809 N. Cahuenga Blvd., Dept. 24 Los Angeles 38, Calif. sound level more restrained 'price slightly higher in Canada. year than it has been in years past. Angeles Show to be held in April. CIRCLE NO. 171 ON READER SERVICE PAGE Ú ELECTRONICS WORLD

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PRECISE MEASUREMENT OF R.F. ter which gives me complete control To the Editors: from the volume as set at the TV to In the matter of mixing heterodyned zero. It has been working fine for 3 or Leisurely taped signals for the purpose of separating 4 years. various combinations of their numerical Am I doing something wrong? If not, orders, it appears that there should be why get more sophisticated? Your ex- on the fabulous realized a distinction in the terminology planation would be greatly appreciated. of the associated circuitry with respect M. G. MARTIN to non -linear impedances, etc. Reference Riverside, Conn. is made to this circuit element in the article `Precise Measurement of Radio The running of long leads from the Frequencies" by J. Richard Johnson in TV set's volume control, which is a high - the August, 1964 issue of ELECTRONICS impedance circuit, often results in seri- WORLD. ous loss of high frequencies and hum Non- linear amplification (detection) pickup. A more satisfactory and equally is a holdover from the old days of "grid - simple technique would be to use a leak" and galena detectors, wherein the low -resistance potentiometer across the amplification was greater in the positive speaker voice -coil leads. direction than in the negative direction, However, the purpose of the article 88 STEREO COMPACT or vice- versa. With the advent of "power in question was not merely to show how Choice of Music -Lovers and detectors" of various types, however, to build a commercial killer. Articles of Music -Makers. and in the absence of any incidental this type also serve to introduce new Features exclusive "Edit - amplification, a far greater efficiency of types of products to our readers and to Eze" cuing and editing. frequency conversion is obtainable with suggest other uses and applications for Superb 30- 18,000 cps fre- a linear rectifier circuit. The more linear such products. If the only job that the quency response for finest the rectifier, the greater this efficiency. device could do would be to act as a mono or stereo recording A perfect rectifier would thus be more commercial killer, then we feel reason- with three hyperbolic heads. properly classed as a unilateral device ably certain that the company would Monitor- off -tape, Sound on rather than a non -linear one. realize that there are simpler ways of Sound, Erase -Protek, auto- Modern diode rectifiers (more prop- doing the lob and would not have come matic shut -off, tapelifters, erly demodulators than detectors ) oper- out with this product which, indeed, are but some of the many ate at comparatively high signal levels has many other applications suggested features to let you thorough- which tend to wash out the small degree by the one shown. -Editors. ly enjoy high quality tape of non -linearity at the lower knee of a a recording. their curve, and it becomes desirable to PIANO TUNING ELECTRONICALLY 4 -track model $339.95 operate them up on the linear portion of To the Editors: 2 -track model $347.95 their characteristic slopes in order to This is in answer to many inquiries I Walnut enclosure 15.95 $ obtain the most linear output wherever have received concerning the availa- For portable model with so desired. This is of paramount interest bility of the book Piano Tuning and speakers ask to see the in the design of beat- frequency audio Allied Arts which I mentioned in my "880." oscillators, wherein the ratio of the article "Piano Tuning -The Electronic mixed radio frequencies is maintained Way" ( September issue) . near a ratio of approximately 10:1 for The book is available from the Tuners closest to sine -wave audio output. Supply Co., 88 Wheatland St., Somer- FRANK J. BL'RRIs ville, Mass., at a price of $6.15 postpaid. Yucaipa, Calif. FREDERICK VAN VEEN General Radio Co. REMOTE VOLUME CONTROL West Concord, Mass. To the Editors: a a a Please refer to "Remote Volume Con- CITIZENS BAND DSB MADE BY SKILLED trol" by Charles Martel in your July is- To the Editors: AMERICAN CRAFTSMEN AT sue. The article by Bruce E. Packham in I am puzzled. I also have a commer- your August issue ( "DSB and the Cit- cial killer by my easy chair, with the izens Bander ") is open to question. If ing OF MINNEAPOLIS, INC. same two connections to the present he is talking about improperly adjusted, volume control, the same two small low - cheap equipment, and lack of know - 9600 Aldrich Ave. So. Minneapolis, Minn. 55420 voltage wires, etc. On the end of the how, then he may be right. I wont take J wires I placed a 25,000 -ohm potentiome- up my time or yours in technical rebut- CIRCLE NO. 252 ON READER SERVICE PAGE 12 ELECTRONICS WORLD

www.americanradiohistory.com HOBSON'S CHOICE? SNEVER AGAIN!

If, in 1631, you went to rent a horse from Thomas Hobson at Cambridge, England, you took the horse that stood next to the door. And no other. Period. Hence, Hobson's Choice means No Choice.

And, as recently as 1961, if you went to buy a true high fidelity stereo phono cartridge, you bought the Shure M3D Stereo Dynetic. Just as the critics and musicians did. It was ac- knowledged as the ONLY choice for the critical listener.

Since then, Shure has developed several models of their Stereo Dynetic cartridges-each designed for optimum performance in specific kinds of systems, each designed for a specific kind of porte -monnaie. We trust this brief recitation of the significant features covering the various members of the Shure cartridge family will help guide you to the best choice for you.

THE CARTRIDGE ITS FUNCTION, ITS FEATURES ... IS YOUR BEST SELECTION The ultimate! 15° tracking and Bi- Radial Ellip- If your tone arm tracks at 11/2 grams or less tical stylus reduces Tracing (pinch effect), IM (either with manual or automatic turntable) - and Harmonic Distortion to unprecedented and if you want the very best, regardless of lows. Scratch -proof. Extraordinary quality con- price, this is without question your cartridge. trol throughout. Literally handmade and in- It is designed for the purist ... the perfection - dividually tested. In a class by itself for repro- ist whose entire system must be composed of ducing music from mono as well as stereo the finest equipment in every category. Shure's V-15 discs. finest cartridge. $62.50.

Designed to give professional performance! If you seek outstanding performance and your Elliptical diamond stylus and new 15° vertical tonearm will track at forces of 3/4 to 11/2 grams, tracking angle provide freedom from distor- the M55E will satisfy -beautifully. Will actually tion. Low Mass. Scratch -proof. Similar to V -15, improve the sound from your high fidelity except that it is made under standard quality system! (Unless you're using the V -15, Shure's M55E control conditions. finest cartridge.) A special value at $35.50.

A premium quality cartridge at a modest price. If you track between 3/4 and 1V2 grams, the 15' tracking angle conforms to the 15° RIAA M44 -5 with .0005" stylus represents a best -buy and EIA proposed standard cutting angle re- investment. If you track between 11/2 and 3 cently adopted by most recording companies. grams, the M44 -7 is for you . particularly if IM and Harmonic distortion are remarkably you have a great number of older records. low . cross -talk between channels is ne- Both have "scratch- proof" retractile stylus. M44 gated in critical low and mid -frequency ranges. Either model under $25.00.

A top -rated cartridge featuring the highly For 2 to 2'/2 gram tracking. Especially fine if compliant N21D tubular stylus. Noted for its present set -up sounds "muddy." At less sweet, "singing" quality throughout the audi than $20.00, it is truly an outstanding buy. ble spectrum and especially its singular re- if you own regular M7D, you can up- creation of clean mid -range sounds (where (Also, it for higher compliance and lighter most of the music really "happens ".) Budget- grade tracking by installing an N21D stylus.) priced, too. If floor vibration is a problem. Saves your A unique Stereo -Dynetic cartridge head shell records. Models for Garrard Laboratory Type assembly for Garrard and Miracord automatic "A ", AT -6, AT -60 and Model 50 automatic turntable owners. The cartridge "floats" on turntables and Miracord Model 10 or 10H counterbalancing springs ... makes the stylus turntables. Under $25.00 including head shell, M99 scratch -proof . . . ends tone arm "bounce." .0007" diamond stylus.

A best -seller with extremely musical and trans- If cost is the dominant factor. Lowest price of parent sound at rock -bottom price. Tracks at any Shure Stereo Dynetic cartridge (about

pressures as high as 6 grams, as low as 3 grams. $16.00) . .. with almost universal application. M3D The original famous Shure Dynetic Cartridge. Can be used with any changer. Very rugged.

-- I---IVRE e CD t1ftF'LG-. HIGH FIDELITY PHONO CARTRIDGES ... WORLD STANDARD WHEREVER SOUND QUALITY IS PARAMOUNT Shure Brothers, Inc., 222 Hartrey Ave., Evanston, Illinois December, 1964 CIRCLE NO. 217 ON READER SERVICE PAGE 13

www.americanradiohistory.com tal, but Nir. Packhaln had better come down from his ivory tower to practical realism. If he is an amateur, then so much the more. I have been utilizing DSB and SSB since 1953, including use on the Cit- izens Band (11 meters). Ask any ham who has been working SSB or DSB for 5 to 7 years the relative merits between AM and SSB or DSB and become more educated. And there are thousands of these hams. C. M. PRUETT, K4BHV Atlanta, Ga.

We are quite .sure that neither we nor our author would disagree with Reader Pruett insofar as the merits of single - sideband equipment are concerned. As a long time hang who has used SSB, we don't have to be sold on the value of SSB. Such equipment has proven its use - f ulnoss not only on the amateur bands but also for military applications. The type of equipment that the author was discussing, however, was modified double -sideband CB equipment in which a portion of the carrier is transmitted. His point was that some of this equipment results in only mar- ginal improvement in performance. With pure DSB, using complete carrier suppression, or with SSB, there is no question as to the improvement in per - formance and range. -Editors. ff SIMPLE "Q" METER To the Editors: In my article "Design of Simple `Q' Meter" (September issue), the formula for calculating inductance from the coil's Triple dimensions was omitted. This formula will give the inductance accurate to about 1 %, thus greatly increasing the your tape recording calibration accuracy of the "Q" meter. The formula is as follows: n -r- L = fun (buy Tarzian Tape three reels at a time!) 9r + 101 where L is inductance in microhenrys, n is number of turns, r is radius in inches, and 1 is length in inches. There are some sounds that you plan to preserve. You know in advance - Carefully count the number of turns, "Here is something I will want to keep, permanently, on tape." You're ready measure the coil dimensions, and calcu- for them. late the inductance from these figures. There are other sounds, though, that you can't predict or schedule. They As stated in the article, the inductance just come along, never to come again. Do you have an extra reel of tape on will be about 100 microhenrys for the hand? Are you ready for the moment that cannot otherwise recur? dimensions given, but the use of the Why not take this good advice? When you buy tape, buy at least three reels. formula will allow corrections for errors in turns counting, form size, and wire And brand name tape, so you can be buy confident of its quality and certain insulation thickness variations. For in- it won't harm your recorder. stance, the actual (calculated) induct- Of course, we hope you'll choose Tarzian Tape. We thoroughly test other ance of my standard coil turned out to brands along with our own -and the impartial equipment in our labs assures be 110 microhenrys. us that you can't do better. DAVID H. SANDROCK FREE: Our 32page booklet tells you how to get more out of your tape recordings. Tuscon, Ariz. Write for your copy. The editor who handled the story felt that the above formula, included in SARKES TARZIAN, Inc. Author Sandrock's original story, would World's Leading Manufacturers of TV and FM Tuners Closed Circuit TV Systems Broadcast be fairly familiar to many of our readers. Equipment Air Trimmers FM Radios Magnetic Recording Tape Semiconductor Devices MAGNETIC TAPE DIVISION BLOOMINGTON, INDIANA However, in answer to some inquiries, Export: Ad Auriemo, Inc., N.Y. Conodo: E. J. Piggott Enterprises Ltd., Toronto, Ont. here it is.- Editors

14 CIRCLE NO. 214 ON READER SERVICE PAGE ELECTRONICS WORLD

www.americanradiohistory.com PROFESSIONAL USE ONLY Total Number of Requests

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READER SERVICE PAGE Since many products and services mentioned are primarily for professional use only, we are using two different coupons. To get more information, promptly, about products and services mentioned in this issue, simply circle the number corresponding to the ad or editorial mention and send the proper coupon to us. Your request will be sent to the manufacturer immediately. FOR PROFESSIONAL USE: In requesting information on products and services listed in this coupon it is necessary to fill out the coupon COMPLETELY, stating your company, address, and your function or title. If the coupon is in- complete it cannot be processed. FOR GENERAL USE: In requesting information on products and services listed in this coupon, please use only your home address. You can use both coupons, since each contains specific items, if each coupon is filled out completely.

Mail to: ELECTRONICS WORLD P. O. BOX 7842, PHILADELPHIA 1, PA.

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NEW PRODUCTS & LITERATURE

1 8 12 14 15 22 25 28 29 30 31 32 33 34 35 36 37 38 41 42 45 46 47 54 55 56 58 59 60 61 62 63 ELECTRONICS WORLD (VOID AFTER DECEMBER 31, 1964) 12 P.O. BOX 7842, PHILADELPHIA 1, PA.

December, 1964 15

www.americanradiohistory.com The antenna that challenges NEW "COLORLg/ebG -VE BY /VC Finco's Color Ve -Log challenges all competition on color or black and white reception and stands behind this challenge with a "Guarantee of Supremacy ". The swept element design assures the finest in brilliant color and sharply defined black and white television reception - as well as superb FM monaural and stereo quality. FINCO precision - engineered features make these advanced - design antennas indispensable to good home sight- and -sound systems. And, of course, they carry the famous unconditional guarantee from the leading manufacturer in the field - FINCO. Promote the Color Ve -Log Antennas with pride, sell them with confidence, and profit handsomely.

Boom reinforcing back up brackets One-piece cross -over drive line as- Elements are made of triple thick First from Finco and exclusive - at elements add triple strength to sembly has no joints between adja aluminum to stand up in severe double contact between drive line mounted on cent driven elements. Eliminates weather. Die stamped bracket fas- and driven element bracket assem- the riveted assembly, a rigid, non -crushable 1" heavy loose connections, shorts, broken tened with tough, thick -gauge rivet bly for perfect drive -line support rolled drive line sections. Polystyrene holds proportional length sleeve and electrical continuity. Positive, duty square boom. Boom square from 11/4" diameter round snap -lock spacers, with center 'air reinforcing shell into which ele- vibration -free, non - corrosive con- aluminum for increased strength. insulator' space. ment fits. tact. Write for color brochure #20 -307, Dept. 410 WORLD 16 ELECTRONICS

www.americanradiohistory.com all competition!

VL -10 9 driven elements 1 parasitic element List prie $34.95 Featuring Finco's Exclusive Gold Corodizing

ti? VL -5 VL-7 Ado 5 e ement VHF-FM 7 eleme-it VHF-FM 5 driven elements 7 driven elements Lis- price $16.95 List pr ce $23.95

finco's boom -mast bracket, rust - High impact polystyrene insulators proofed by zinc plate -gold di- :hro- an reinforced with strong alumi- .i. mate dip process, is the fittest nL m shields. This gives quadruple did available. It has positioned cleats st ength in supporting triple -thick !i to assure sag -free positive cirec- snap -in elements. Lifetime assem VL-15 VI-18 tion of the antenna. Locks tight. bli with fitted aluminum cup to 15 element VHF-FM 18 element VHF-FM 9 do iven elements 9 driven elements Can't tilt. Antenna stays in proper held oversize aluminum rivet. 6 parasitic elements 9 parasitic elements position at all times. List price $46.95 List pr ce $54.50 The FINNEY Company 34 Interstate Street Bedford, Ohio

December, 1964 CIRCLE NO. 216 OH READER SERVICE PAGE 17

www.americanradiohistory.com HI -FI PRODUCT REPORT

EVA TESTED BY HIRSCH-HOL'Ch LABS LAB TESTED Uher 8000 Tape Recorder Electro -Voice "Sonocaster" Speaker

Uher 8000 Tape Recorder ments. A control labeled "lial..ucc actually switches the playbacl, amplifier For a copy of manufacturer's brochure, circle /No. 60 on coupon (page 15) from the input signal to the output of the playback amplifier for monitoring purposes. In mono reproduction it does control the volume bulnuce between the two built -in speakers. Colored lights clearly indicate the record or playback status of each channel, according to the setting of the function switch. Twin "vu-type" meters monitor recording and playback levels. There is an interlocked "Record" button, a "Pause" button which stops and starts the tape almost instantaneously, and an index counter. If the tape is fitted with metallic end leaders, the machine will shut off automatically at the end of a IT i.; interesting to see how much oper- Although other recorders have many reel. ating flexibility can be built into a of these features, most of them require The stopping and starting of the tape tape recorder without unduly increasing signals to be "patched" from the play- transport is controlled by two "piano - its size, weight, and cost. The Uher back output to the recording input. In key" push -buttons. A bar in front of the 8000, manufactured in Wiest Germany, this unit, all signal connections are macle "Stop" button is moved to right or left is certainly one of the most versatile ma- by the function selector. for fast forward or rewind operation. All chines on the market, yet is complete in The speed change knob has an "off" of the connectors are of the Hirsch/tin/in an attractive, plastic- covered case about position between each pair of speeds and type widely used in Europe. Adapter the size and shape of a portable type- turns the entire machine on and off. Be- cables, which terminate in standard writer, and weighs about 23!_ pounds. ing transistorized, it comes on instantly, American phono plugs, are supplied. Because of its fully transistorized cir- without any warm -up. The recorder has The line cord is stored in a compartment cuitry, it consumes only about 30 watts built -in power amplifiers and monitor in the rear of the recorder, which is cov- from the per line. speakers, with playback volume and ered by sliding doors when not in use. The recorder is a four -speed machine, tone controls. It can also drive external The 7' _ -ips playback response, meas- with tape speeds of ' íu, 1''s, 3 :%, and speakers or amplifiers. There are sepa- ured with an Ampex 31:321-04 tape, was 71 ips. It will record or play back four - rate recording level controls for micro- ± 2.5 db from 80 to 15,000 cps, and was track mono or stereo tapes, and has sep- phone and radio inputs, which can be down 6 db at 50 cps. The over -all re- arate recording and playback systems so mixed. No provision is made for individ- cord /playback frequency response was that a program can be monitored from ual channel level or balance adjust- within ±3 db from 30 to 20,000 cps at the tape as it is being recorded. By 5

means of a single function -selector 1 switch, it can operate in mono or stereo ® ® J ti o -._ .. modes, record a delayed playback signal ó CH si- 5 UHER 8000 RECORDER for echo effects, play one track while -- I 7I/2-IPS PLAYBACK RESPONSE

r_ - multaneously recording on the other, and AMPEX 31321-04 TAPE ...... f f ... . ovr 5Kf IOKC. 20 C. copy one track on to the other, combined 20 50 100 FREQUENCY -CPS with yin external program source. A "Dia- Pilot" feature allows a control +5 signal to be recorded on one track sinnil- o tarleously with a spoken commentary on UHER 8000 RECORDER the other track, by pressing a button on OVER-ALL RECORD /PLAYBACK RESPONSE the recorder. In playback, this tone can i 7 I/2 IPS be used to change slides automatically

- _ for auto- - SIg IPS I \ on a slide projector designed _15 upon - - -- Ii' f matic operation. This makes possible a _ ('`i ?- f I fully slide program, with com- 2KC. c. IOKC automatic 20 50 IOO 200 500 IKC. mentary, without an operator. FREQUENCY -CPS ELECTRONICS WORLD 18

www.americanradiohistory.com Scott's top rated LT -110 FM Stereo Tuner Kit now at a new low price...$139.95! ...1.88 uy sensitivity by a home alignment procedure without instruments.. . an exceptional feat ..." Electronics Illustrated

:v»cutsr; trÁi®

,e`4z _,u.,w.benrr.:;,ir,. -. .> ...... ,+rx w«.,. , . =..+,4.- ...... F.H Here's terrific news for kit builders! Now, the advanced multiplex equipment available. Among famous Scott LT -110 tuner kit ... the same kit the LT- 110 -B's many pluses: Stereo Separation top rated by every audio expert . . . the same in excess of 30 db, Sonic Monitor Stereo indicator, superbly engineered FM Stereo tuner built by 60 db signal -to -noise ratio, sensitive tuning meter. thousands of hi fi enthusiasts ... is now available Here's what the technical editor of Electronics in handsome new styling at a truly modest price. Illustrated said about the LT -110: "If you have Look at the outstanding features of this superb hesitated to go into stereo FM because of im- tuner. It includes a heavily silver -plated front end agined complexities and highly technical skills that is pre -wired and tested in Scott's engineering and knowledge that might be required, fear no laboratories. The critical multiplex section is also more. The LT -110 shows you how t) enjoy stereo completely pre -wired and tested with the most FM the easy way." rFREE 1965 STEREO GUIDE H.N. Scott, Inc., 111 Powdermill Rd., Maynard, Mass.

160 -12

Please send me your flew 20 -page full -color New LK -72B 80-Watt Stereo Am- LK -48B 48 -Watt Complete Stereo Exclusive FULL -COLOR instruction 1965 Stereo Guide and complete catalog. plifier Kit. Here's a popular inte- Amplifier Kit. More than enough Book "eliminates just about the grated stereo amplifier kit at an power for the majority of music last possible chance of wiring Send me complete information on new con- outstanding price. Rugged stereo systems. The all -new LK -48B has errors . ' Every part and soles by Scott . component quality in output stages deliver 80- watts, two new convenience features, a every wire are shown in natural beautiful, hand -finished cabinets. :an be used with any speaker switched front panel headphone color and proper position. In ad- systems. Every conceivable con- output for private listening, and dition, each full -color illustration is found on this ver- output in the instruction book is ac- trol feature a powered center channel Name satile amplifier including a to drive extension speakers. 13 companied by its own PART - switched front panel headphone front panel controls. Complete CHART, another Scott exclusive. output, complete recording facili- tape recording facilities. Typical The actual parts described in the Address ties, and provision for driving Scott luxury features include all - illustration are placed in the 3 third or center channel loud - aluminum chassis and DC- operated exact sequence in which they are City Zoie.... State speaker system without additional heaters for lowest hum. Only used. amplification. Only $149.95 $129.95 xport: Scott International, I11 Powdermill Road, Maynard, Mass. Canada: Atlas Radio Corp., 50 Wingold Ave Toronto. Cable HIFI SCOTT® Price slightly higher West of Rockies. Subject to change without notice. December, 1964 CIRCLE NO. 200 ON READER SERVICE PAGE 19

www.americanradiohistory.com 7I., ips, 23 to 7000 cps at :3"i ips, 22 to Despite it unusual flexibility (or per- 5000 cps at 1' ips, and 22 to 3100 cps Imps because of it), the unit does have W910 at '7'1I; ips. The fast -forward and rewind its drawbacks. The functions of several tape speeds Nverc relatively slow, requir- of the controls are by 110 means clear PUTS THE WORLD AT ing about 3 minutes to handle 1200 feet from their labeling. The instruction man- of tape. ual is comprehensive and is written in wow and flutter at 71,:' ips were 0.02% four languages. This is not a machine YOUR FINGER TIPS! and 0.10`F respectively as measured with which can be used without studying the the Ampex 31326 -01 tape. At slower manual, no matter how familiar the user speeds, no wow or flutter could be is with other tape recorders. heard, except at '''íl: ips, where the flut- The sound quality through the built- ter was audible. Since this speed would in speakers is minimal; in fact, negligible normally be used only for voice record- difference can be heard between the 154g ing, this is of little importance. The sig- and î's ips tape speeds. nal -to -noise ratio of the recorder ranged A machine such as this is most likely from 51 clb at 7' _ ips to 42 clb at '7'0; to appeal to the user with special inter- ips. ests and requirements, such as slide pro- In use tests, the recorder proved itself gramming, dictation, special -effects re- capable of excellent sound when played cording, and the like. It is bard to beat through an external amplifier and for such applications and it is also capa- speaker system. Good "background -mu- ble of good, high -fidelity sound when c" quality was obtained at 174 ips. used with an external playback system.

Using a 3600 -foot reel of 1 _ -mil tape, up Its light weight and compact dimensions to 13 hours of stereo or 26 hours of mono make it a truly portable recorder, un- programs can be recorded on one 7" reel like many which have carrying handles FAMOUS at 1 ips. A voice- operated dictation ac- but are actually too heavy to carry for "SECOND OP" cessory, which starts and stops the tape any appreciable distance. automatically, is. available. Using the The Ulu'r 8000, which is handled in Essential DX operating aid, provides ips speed, of vital data like: beam headings; list of over 50 hours dictation the C.S. by Martel Electronics Sales, world QSL bureaus; includes logging can be recorded on one reel of tape. Inc. of Los Angeles, sells for 5499.95. space. See needed prefixes at a glance, increase your odds of a OSO because you have full information Electro -Voice "Sonocaster" Speaker instantly. For copy of manufacturer's brochure, circle No. 61 on coupon (page 15). $1.00 WITH the growing popularity of outdoor and patio living, there is a corresponding need for high- fidelity components that cali bring good music out of doors. It is a simple matter to extend speaker wiring, but conventional speakers are rarely adaptable to out -of -doors use. Even if they are small and light enough to be carried outside, their fur- niture finishes are easily damaged by still and rain. and most speaker cones do not take kindly to wetting. The new Elcctro -Voice " Sonocaster" is an interesting and very satisfactory solution to the outdoor speaker problem. NEW "Q" DIAL It is a portable unit, equally suited to being carried from room to room within trip. It resembles a small piece of lug- the house, out Of doors, or on a vacation gage, about the size of a portable type- A must for every active ham ; r operator, ; _-_!, or C.B. Over a dozen vital informa- I tion tables including: Q- signals, 10- signals, abbreviations, all U.S. radio districts and prefixes, time conversion, logging space for CW- SSB -CB. Saves time for efficient operation. _.:.qQQy

At your E -V microphone headquarters, FREOUENCY RESPONSE-E-yE -E -v SONONOCASTESTER or send $1.00 each to: AVERAGE OF s INDOOR RUNS

I CORRECTED FOR MICROPHONE RESPONSE ELECTRO- VOICE. INC. INPUT =I WATT 20i..... Dept. 1243N, Buchanan, Michigan 49107 C, 2C 50 C 200 500 !RC. 2KC. SKC. IOKC. 2OKC, cc

®1;: !yM^ A_'- SETTING NEW STANDARDS IN SOUND IIi®I>II== ' FREQUENCY -CPS CIRCLE NO. 180 ON READER SERVICE PAGE 20 ELECTRONICS WORLD

www.americanradiohistory.com Can you recognize these three great stars?

The first two are obvious to movie goers: Rock Hudson Concertone 800 is the only stereo tape recorder with and Doris Day starring in Universal's new comedy, double Reverse -o- matic® and six heads -allowing you "Send Me No Flowers." The third is ours and it's on to record and play continuously without reel turnover. the table. It's the Incomparable Concertone 800. This The 800 (portable or tape deck) is priced realistically unique stereo tape recorder plays a vital rope in this and provides an exclusive combinat on of features. It hilarious new movie. When the script called for a tape starts as low as $379.95. Send for a free Concertone recorder, Universal Pictures wanted the finest, most 800 brochure and the name of your nearest dealer. modern machine available. That's why they selected Write to Concertone, Box 3866, South El Monte, Calif. the Concertone 800 to appear. It's as modern and C O N C E R T O N EC sophisticated as the live stars of the movie. D The

ROCK HUDSON and DORIS DAY star in "SEND ME NO FLOWERS"

December, 1964 CIRCLE NO. n70 ON READIER SERVICE PAGE 21

www.americanradiohistory.com writer, with a carrying handle on top. New Bogen sound products The "Sonocaster" is made of a tough, flexible, beige -colored plastic, and weighs only 8 pounds. It has mounting deliver the message best clips for permanent or semi -permanent «all or post installations. According to the manufacturer, the speaker is unaffected by weather and may be left out of doors permanently. In the factory In the school Its driver is an 8 -inch unit, completely Reach important executives and Efficient communications systems waterproofed, including the cone. It has production personnel in noisy areas. guarantee, increased efficiency - a 23 -inch -diameter "whizzer" cone, for Provide background music for im- portable players enhance music, improved high- frequency response. with proved morale and production. drama, and extra -curricular pro- a mechanical crossover from the main Bogen does it best. grams. Bogen does it best. cone at 6000 cps. This is the well -known "Radax" design which has been used in E -V speakers for many years. The New! speaker is built on a heavy, die -cast frame and has a ceramic magnet assembly. The specifications of the speaker state that its frequency response is from 70 to 13,000 cps, with a peak power handling lllii-1111 capacity of 30 watts. We tested the unit ïi indoors, making response measurements at eight different microphone locations. II The averaged response curve is note- New Bogen VP " Series All- Transistor worthy for its exceptional smoothness at Portable High Fidelity Transcrip- middle and high frequencies. From 330 tion Players. 20 to 40 watts (sine cps to 12,000 cps, its output is uniform New SA" Series Intercom /P.A. wave ratings). Handsome carrying within ±3 db. At lower frequencies, the Systems. High - powered (12w.) in- naturally falls off, with a hole at cases. Exclusive variable -speed output tercoms for 21 or 42 stations; op- 250 cps and a peak at 150 cps. These are control. Automatic tional chime and light annunciators; cueing. Inputs: probably due to resonance effects within emergency all -call paging; inputs 2 mic., tape, tuner, phono. the non -rigid enclosure, which vibrates for music program sources; 25v. perceptibly. The harmonic distortion is acceptably low down to 70 cps, and the output; mixes private and non - In the church total response variation from 70 to 15,- private remotes in any combination; Sound systems deliver the "mes- 000 cps is ±7.5 db. Not only does this provision to add booster amplifier. sage" loud and clear throughout diminutive speaker, which encloses less

the church -serve to assure suc- than ', cubic foot, cover most of the au- cessful social events as well! Bogen dio frequency spectrum as well as many does it best. far larger and costlier speakers, but it In the office easily meets its advertised specifications. Inter -office phones save time and This is relatively unusual among speak- steps, keep the telephone switch- ers, in our experience. board from being overburdened. The tone -burst response of the speaker Bogen does it best. was quite good at low and high frequencies, although it had a pronounced ringing at '700 cps which appeared to be associated with an enclosure resonance. At 5 kc., the tone -burst response was Bogen MX30A and MX60A Deluxe nearly perfect, which is consistent with flat response in the upper 30 -watt and 60 -watt P.A. Amplifiers the speaker's frequency region. -with 5 mic. inputs; peak limiter; The unit sounds very fine indeed. Its power curve cps; Series "TSL" Telephones. Sell your -21 to 30,000 quality is fully compatible with any good low- customer the economy of unique calibrated frequency notch high -fidelity system, with clean, ex- filter; 5 speech inter -office telephone. Fast (no dial- filters; remote vol- tended highs and good over -all defini- ume control and mic. precedence; ing); 100% trunkage; no central tion. The lows, of course. are a trifle thin, frequency response but one is not aware of this unless the switchboard; conference calls; desk -10 to 38,000 cps; wide variety of accessories. sound is compared to that of a larger or wall mounting; provision for system with good bass response. It can paging thru plant P.A. system. Sys- For Fall Catalog write desk W -12, be used effectively to up -grade the sound tems for up to 16 phones. ra- Bogen Communications Div., of portable phonographs, transistor dios, TV sets, as well as for portable Paramus, N.J. and p.a. applications. Voices are reproduced with excellent, natural quality, free from LEAR SIEGLER, INC. boominess or unpleasant coloration. BOGEN is COMMUNICATIONS DIVISION IS, The Electro -Voice "Sonocaster" priced at $36.00.

22 CIRCLE NO. 137 ON READER SERVICE PAGE ELECTRONICS WORLD

www.americanradiohistory.com New COLOR BRIGHT 85 picture tube brings more natural color to television and increases monochrome brightness 43 %*

The startling news in the television in- Because the COLOR BRIGHT 85 tube sides the increased brightness, there's dustry is Sylvania's new picture tube, is really bright, dealers can demon- improved contrast in a sharp, vivid and its new, truer red phosphor. strate color TV effectively in normally picture. EUROPIUM RED, developed at lighted showrooms. As the set's bright- The new; exciting COLOR BRIGHT GT&E Laboratcries, is the brightest ness is adjusted, the colors remain 85 picture tube is a product plus from red known to the industry. And, to true -not shifting to unnatural tones Sylvania for the entire color television match it, now the full brightness of in the highlights of the picture. industry, and particularly for dealers. blue and green is used. The result is Another thing, black and white per- In color, as in black and white, you a color picture tube that gives the en- formance is far better than you've know it's good business to handle the tire television industry a boost. ever seen before in a color tube. Be- Sylvania line. IA SYLVANSUBSIDIARY OF GENERAL TELEPHONE & ELECTRONICS GTE NEW CAPABILITIES IN: ELECTRONIC TUBES SEMICONDUCTORS MICROWAVE DEVICES SPECIAL COMPONENTS DISPLAY DEVICES

"Tests !how ho COLOR BRIGHT BS tube " 'r , cceroge, then stc '..dord color picture tubes.

December, 1964 23

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EICO 232 VTVM EICO 667 TESTER EICO 324 RF SIGNAL EICO 460 5 -INCH PEAK -TO -PEAK GENERATOR OSCILLOSCOPE TUBES & A MUST FOR COLOR OR TRANSISTORS DC WIDEBAND B & W TV AND 0 -4.5 MC FOR INDUSTRIAL COLOR & B & W TV SERVICE & USE. 7 NON - V SKIP RANGES : s p , LAB USE. PUSH - DC VER - O N ALL 4 PULL FUNCTIONS. sp A TICAL AMP. TESTS RECEIVING. SPECIAL 150 KC /S TO 435 MC /S RANGE. BAL. ORUNBAL. WITH INPUT. AUTO- -PROBE PURPOSE, NUVISTOR AND FOR IF -RF ALIGNMENT ANE1 UNI COMPACTRON TUBES FOR DY- SIGNAL TRACING OF TV, FM, MATIC SYNC NAMIC CONDUCTANCE. TWO - AM, CB AND MOBILE. BUILT -IN LIMITER AND KIT $29.95. STEP TRANSISTOR TEST. AND EXT. MODULATION. AMP. WIRED $49.95. KIT $79.95. WIRED $129.95. KIT $29.95. WIRED $39.95. KIT $89.95. WIRED $129.50.

EICO 1064 DC NEW EICO 3566 SOLID STATE FM -MPX POWER SUPPLY NEW STEREO TUNER AMPLIFIER FOR BENCH EICO SENTINEL 23 CITIZENS RADIO T E S T I N G AUTO RADIOS. CB, MOBILE IN THE HIGHEST AND TONE QUALITY RANK, WITH EQUIPMENT. 111.11111118- 43 TRANSISTORS, VOLTMETER ti ti' 19 DIODES. 6 RECTI- A N D AM- 117J 4 V' 4 FIERS. 112 WATTS METER. LOW INTO 4 OHMS 72 RIPPLE FOR TRANSISTOR W A T T S I N T O 8 OHMS. 38-40 DB CHANNEL SEPARATION. AUTO- EQUIPMENT. CRYSTAL CONTROLLED TRANSMIT AND RE MATIC STEREO SWITCHING. INTERSTATION MUT- 0-8V/ 0-16V CEIVE ON ALL 23 CHANNELS. TRANSISTOR AND MPX PRE -WIRED METER. EXCEEDS ING. FRONT -END. IF SECTIONS OUTPUTS. POWER SUPPLY. "S" ALL AND PRE -ALIGNED. PLUG -IN TRANSISTORS. FCC STANDARDS. A BEST BUY AT ONLY KIT $45.95. WIRED 554.95. $199.95 WIRED. KIT ONLY $229.95. WIRED WITH CAB. 5349.95. 1 FICO Electronic Instrument Co., Inc. Flushing, New York 11352 MOST COMPLETE LINE SEND EW12 I SEND 1965 KIT -O -LOG LISTING 230 FICO PRODUCTS. OF KITS AND WIRED FOR TEST EQUIPMENT, CB I NAME AND HI -FI COMPONENTS. FREE ADDRESS KIT -O -LOG I CITY STATE ZIP L 24 CIRCLE NO. 179 ON READER SERVICE PAGE ELECTRONICS WORLD

www.americanradiohistory.com NEW SCR DEVELOPMENTS

Some of the recent four -layer gate- controlled semiconductor switches are very low in cost, are self -protecting, and are transient -immune. Bilateral SCR's are also readily available.

By DONALD LANCASTER

THE silicon controlled rectifier has come of age. These four-layer gate -controlled semiconductor switches are now used in an amazingly diverse range of applications. SCR's are now directly replacing ignitrons, power thyratrons, and other bulky, inefficient devices. operating as high as 1500 volts at current levels exceeding 500 amperes. They are now serving as microminiature, lightweight switches in computer and satellite circuitry, reliably switching milliamperes of current at low voltage levels. They enable power supplies and regulators to operate in switching mode at efficiencies very nearly approaching 100%. SCR's serve in motor and power -tool controls that provide variable speed and variable torque at the turn of a knob. An entire industry has begun with the SCR home light dimmer and workshop power -tool controls. In special circuits, the SCR is an efficient radar modulator, a power inverter, and an effective d.c.- to -d.c. converter. There have been some recent developments in the SCR field that promise to make these components even more useful and may possibly create a whole new class of circuitry that has no present counterpart. These same developments can also greatly simplify currently popular devices as well as contribute to reduced cost. These recent developments take several directions, the most significant of which are extremely low -cost SCR's, self -protecting SCR's, and transient- immune SCR's. Of equal importance are newly

Some typical examples of low -cost silicon controlled rectifiers showing their simple cose design.

December, 1964 25

www.americanradiohistory.com 8- ampere current level. General Electric uses a press -fit cup for its economy SCR's, similar to the diodes used on automotive alternators. Many other manufacturers use this same package on their 18- to 25- ampere medium -power SCR's. This type of package lends itself to easy mounting as it is simply pressed into a .500 -inch hole in a heat sink. An arbor press

IIMEM is normally used for this operation, but an ordinary bench vise works just as well. Fig. 7. When the reverse breakdown of a non -uniform p -n junction (left) is exceeded, it breaks down at its weakest point. Manufacturers, in their volume packaging, haven't forgot- High current density at this point melts the structure and ten the small- quantity manufacturer or the experimenter. creates a short. A uniform, controlled -avalanche structure Almost all of the types shown have modified designs which breaks down uniformly across the entire surface. Under these conditions, the current density is low and no damage is done. + AMPS + AMPS available SCR "offspring." These include a class of SCR's that can be turned off by a gate pulse as well as on, and new bilateral SCR's that work equally well in either current direction. The former may be operated from an uninterrupted, uncommutated d.c. source. The latter are capable of operat- -VOLTS (+1 -VOLTS ( +1 ing directly off the a.c. line, allowing a single bilateral SCR to provide full -wave, non -inverted proportional a.c. control without the use of other power components. We will assume that the reader has a basic familiarity with the conventional SCR and its operation. (See "Silicon Con- trolled Rectifiers" in the October 1963 issue of this magazine, 1 -) ( -1 one of the SCR manuals, or design information provided by ORDINARY SCR CONTROLLED -AVALANCHE SCR virtually all the SCR manufacturers, Motorola, Texas. Instru- Fig. 2. The sharp zener knee in the reverse direction of the controlled -avalanche SCR makes this device self -protecting. ments, General Electric, RCA, Transitron, Sarkes Tarzian, Transients are absorbed without local destructive breakdown. International Rectifier, SSPI, Westinghouse, among others. ) Suffice it to say that the SCR is a four -layer semiconductor provide studs or additional leads to allow the traditional nut- switch that is capable of switching large amounts of current and -bolt type of assembly. Obviously, these additions increase through the use of minute control signals applied to a third the SCR cost, but in many instances the modified case is or gate electrode. This article will investigate these new de- priced only 10 to 25 cents above the production case. velopments which promise to make the new silicon controlled SCR's are now available from many manufacturers in a rectifiers intrinsically more useful. choice of case connections. In the older SCR's, the case was invariably connected to the anode of the structure to permit Economy SCR's rapid dissipation of heat. The new planar construction elim- One of the most welcome developments is the creation of a inates this requirement as heat sinking at the cathode is just line of economy SCR's which are designed for the consumer as efficient. The price of the SCR with either connection is electronics market for use in appliances and dimmers. SCR's the same. This leads to greatly simplified heat -sink design in are now available, in quantity, for less than $1.00 apiece and circuits operating two SCR's back -to -back or in circuits using singly for slightly over $1.50. These SCR's can control 5 am- multiple SCR's. This, in itself, can drastically reduce coin - peres at 200 volts, while lower voltage SCR's are available at plexity and assembly time in many circuits. even lower cost. The new SCR economy has been achieved There is a tremendous hidden significance in this new SCR by employing several techniques. One is planar construction, economy. Previous SCR applications replaced the thyratron, a more efficient method of fabricating the silicon structure which is the heart of the SCR. A second factor is sheer volume of production and high production yields made possible by SWITCH OPEN-ON volume markets and automatic equipment. CLOSED -OFF The most significant contribution to reduced cost has been the redesign of the case. Since a large fraction of any semi- OFF conductor's cost is in the case, the leads, and the assembly, the hermetically sealed, stud -mounted design has been aban- cloned in favor of cases which are merely tabs or small cups of metal. These inexpensive packages are entirely adequate for the environmental conditions encountered in consumer products. Each manufacturer has his own approach to an ideal economy package. Some of these are shown in the photographs. RCA uses a flat diamond -shaped washer and a small metal FIXED POWER cup. This is similar to the typical power -transistor case, al- SUPPLY though much lighter and smaller. This package is usually LOAD bolted or riveted to a heat sink. Texas Instruments uses the top -hat diode case, now with two leads out the top. It is soldered directly to a heat sink ( usually with a disc solder pre- (B) form and an oven ) or glued to a beryllium oxide insulating washer. The anode connection is by way of a spring clip or Fig. 3. (A) Using gate turn -off SCR as a latching relay. When directly through the heat sink. The Transitron package is a the gate is pulsed positive, the SCR turns on. With a negative simple cup, somewhat similar to the TI design. pulse, SCR turns off. (B) A switching -mode regulated supply with very high operating efficiency. Varying the on time com- Motorola uses a special cartridge type case designed to fit pared to off time of the fixed power input results in a var- into a fuse clip or be soldered directly to a heat sink. This is iable power output. The filter smooths out the on- off -on -off one of the smallest SCR packages presently available at the waveform so that resultant output is a smooth d.c. voltage. 26 ELECTRONICS WORLD

www.americanradiohistory.com the ignitron, the variable autotransformer, the magnetic amplifier, and others. Practically all present SCR applications have bad their earlier counterparts. The new SCR economies TBS 20AS (TRANSITRON) and small sizes open the way for a host of new industrial and (USE HEAT SINK) consumer applications that have been impractical or pro- II7V.A.C. 601 .IP} hibitively expensive until now. 30:1 TOROIDAL For instance, dimmers built directly into conventional desk TRANSFORMER ER900A I 21 and table lamps will allow the brightness of the lamp to be (TRANSITRON)

varied to suit individual needs. Power tools whose speed or CI- OPTIONAL NOISE-ELIMINATING CAPACITOR torque increases as the trigger pressure is increased are now (A) possible, as is soldering equipment xvith instantly and continuously variable temperature control. Also in the cards are store -lighting fixtures that can automatically compensate for increases and decreases in daylight levels, photographic lighting that provides exact shadow control -the list is limited only by the imagination of the designer. ZJ 257 TRIAL (G-E) (USE HEAT SINKT These are not expensive "dream devices" but currently fea- sible low -cost devices which should be available soon. The currently popular wall- mounting dimmers and home workshop power -tool controls offer just a hint of the vast pos- CI- OPTIONAL NOISE- ELIMINATING CAPACITOR (B) sibilities of economical SCR a.c. proportional control. Fig, 4. (A) The new bilateral SCR's extremely simple light - Self -protecting SCR's dimmer and power -control circuitry. This circuit uses gate - less bilateral SCR to give full -range 600 -watt proportional Protecting SCR's against voltage transients has been a se- control. (B) The gated bilateral SCR allows 600 -watt a.c. vere design problem ever since their introduction. The proportional control with only four parts. Performance and prob- cost are about the some as circuit shown at (A), Both types lem becomes especially critical in high -voltage, high- current of bilateral SCR are available in much higher power ratings. industrial motor and process controls. Transient protection is mandatory in reversing motor drives where a shorted SCR can destroy a motor, or perhaps an entire production line. The specific problem is reverse breakdown. A voltage transient in the forward direction merely turns the SCR on. In the reverse direction, when the peak inverse voltage of the SCR was exceeded, violent breakdown occurred, ruining the SCR and perhaps the rest of the circuit. Previously, SCR controls had to have protecting varistors, thy_ ristors, and other transient suppression circuitry. A new technique eliminates all of this. Called "controlled avalanche" this new breed of SCR's is made to behave like a zener diode when its peak inverse voltage is exceeded. The transient is simply absorbed by the SCR and dissipated as heat. Not only is the SCR not damaged, but it has eliminated a transient that could do further circuit damage. To explain controlled avalanche, we must delve into a bit of solid -state physics. The troublemaker in this case is temperature. If the instantaneous temperature of any part of a semiconductor gets too hot, it simply melts and loses its semi- conducting properties. The cause of temperature is heat and, in this case, the cause of the heat is current. It is not current itself, but currant density (amps. /sq, in.) that causes the destructive temperature rise. This effect can be demonstrated by first passing a 5 -amp current through a #14 wire and then repeating the experiment with #40 wire. Although both wires passed the same Typical mounts for press -fit SCR's. Half -inch hole is used. current, one is still at room temperature while the other has disintegrated in a wisp of smoke. In an ordinary diode or SCR, reverse breakdown first takes By the same token, a substantial current can flow through place in one or two small regions, damaging the device. In a a semiconductor if it flows through the entire available cross zener diode, and in the new controlled -avalanche SCR's, re- section. On the other hand, if that same current is concen- verse breakdown is uniform across the entire junction, pre- trated in a small area, the temperature rise may be destruc- venting damaging local temperature rise. Fig. 2 compares tive. This is shown in Fig. 1, where a uniform and a non-uni- the reverse breakdown of a regular and a controlled -ava- form p -n junction is diagrammed. The non- uniform junction lanche SCR. will reverse breakdown at the defect shown. The resultant Controlled avalanche results from careful SCR design and high current density will destroy the junction at this point. improved control of the SCR properties during fabrication. Since the other semiconductor regions around the defect have Beveling the silicon structure in a critical manner helps cre- not broken down, they conduct no current. The short pro- ate the required uniform breakdown. Passivating the silicon duced exists only over a very small area, but it is still a short. structure (coating with a "paint" of oxide or nitride) also The uniform junction breaks down uniformly. The same cur- prevents edge or surface contamination that could encourage rent as before is now distributed over the entire surface. The uneven breakdown. resultant current density is very low. Although the same The significance of the controlled avalanche SCR lies in its amount of heat is produced in both cases, the uniform junc- inherent self- protection. The SCR is now a transient-eliminat- tion temperature remains at a safe level. ing device instead of a (Continued on page 70) December, 1964 27

www.americanradiohistory.com PORTABLE TV SETS

By LESLIE SOLOMON Associate Editor

With the development of the low -power CRT, a number of transistorized portable TV sets have made their appearance. New a.g.c. systems and a unique method of generating intermediate high voltage have been developed for these circuits. All of the portable TV sets use this type of printed board construction.

IN the early clays of TV, sets were physically large but Although the sets are classified as completely transistor- screens were small, and, in fact, the 10 -inch version ized, they do use tiny, low -power vacuum diodes as high - reigned supreme for a long time. As TV reached more voltage rectifiers. This high voltage (approximately 4 to 8 people, the demand for a larger screen soon followed and set kv.), generated by the horizontal output transformer, is used picture size went up through 19 -, 21 -, 24 -, and even 30 -inch to operate the CRT. For the lower d.c. voltages such as used direct -view CRT's. For a short period of time even these for CRT focus (approximately 0 to 150 v.), second grid were not large enough, and projection systems became the voltage (approximately 300 v.), and the d.c. voltage for the vogue. video amplifier (approximately 60 v.), semiconductor recti- During the past few years, however, some standardization fiers are used. in picture tube size has come about, and the bulk of today's The horizontal output transformer is used primarily as a a.c.- powered sets consist of an 11- to 19 -inch version used power transformer (the horizontal yoke is driven directly as a so- called portable and a 23 -inch version usually used as from the horizontal output transistor), and the vacuum di- the living room set. These are all a.c.- powered and use vac- odes are used as voltage doublers or tripiers to supply the uum tube circuits. There are, at the present writing, some necessary high voltage for the CRT. As these diodes require a.c.- powered transistorized sets appearing on the market. very low filament power, a one- to two -turn filament winding However, this article covers only the fully portable sets; around the transformer core will suffice for their heater op- that is. sets that are not dependent on the a.c. line as a source eration. of power (although they all can be operated in this fashion Set weight ranges from about 8 to 13 pounds. In most if desired). cases, this does not include the weight of the external bat- The key to the fully portable TV set is the transistor and tery and case that may reach another 5 pounds. The one the low -power- consumption CRT. As is well known, the tran- set that includes the battery within the body of the case sistor is perfectly capable of full operation at reasonably low (D('hnonico 4- incher) weighs a total of 8'_ pounds. supply voltages ( about 12 y.) and a lot of basic research has Because the sets are classified as "personal portables," gone into the development of a lose- power CRT. For exam- they have provisions for individual earphone operation. When ple, the 5 -inch rectangular CRT as used in the Sony Model the earphone is plugged in, the loudspeaker is taken out of 5 -303W has a 12 -v. heater at 70 ma. for a total heater power operation. of less than 1 Hyatt; it uses an 8 kv. anode voltage at a beam Disassembly of the sets for service is relatively easy. A current of 50 p.a.; deflection angle is 70 °: it needs no ion trap, typical set uses a number of separate circuit boards that are focusing is electrostatic, and the control grid requires only easily removable from the mounting frame. This permits -- 25 volts for full spot extinction. Although the tube has a rapid replacement of a faulty board so that the set can be diagonal screen dimension of 5% inches, its full length is only placed back in service promptly. (See photo above.) 6% inches. This small tube has a horizontal resolution of 300 Available Sets lines and a vertical resolution of 400 lines for a full picture. Other sets covered in this article also use very low power As previously stated, the sets covered in this article are CRT's. However, there are some differences in the deflection fully transistorized and do not depend on the a.c. power line angle. For example: Delmonico uses a 4',_ -inch, 55° tube; for operation. The sets shown on the cover are representative Son. y uses a 5 -inch, 70° tube; Realtone has a 6 -inch, 90° of those presently available to the prospective purchaser. tube; Sharp uses a 6 -inch, 90° tube; while Panasonic, Philco, Several companies, both Japanese and American, have plans and G -E use 9 -inch, 90° tubes. Without exception, all of to market other screen sizes in the near future. In fact, some these miniature CRT's are rectangular and their screen color of the manufacturers represented on the cover have sets with ranges from black- and -white to an off blue. other size screens on the market now, and the models shown 28 ELECTRONICS WORLD

www.americanradiohistory.com on the cover are only a sampling of present portable lines. FROM VIDEO DET. All presently available, fully portable sets are designed to operate either from a 12 -volt d.c. (battery) source or from the 117 -volt a.c. power line. Almost all have provisions for operation from a 12 -volt automobile storage battery. The battery power for these sets is obtained from recharge_ able cells. One set (Delmonico 4- incher) has the batteries mounted within the body of the TV set while others use some form of separate battery holder. Connection to the set is through a polarized power cable. In some cases, the battery recharging circuit is within the set itself, while in others the recharger is mounted in the battery holder. 25MC. Circuit Innovations DI of the circuitry used in these small sets is quite The bulk COIL ON HORIZ. conventional for transistorized circuits. Tuner circuits, video OUTPUT TRANS. and sound i.f. stages, audio amplifiers, and powerssppply circuits are not very different from set to set. Most of them (A) use four stages of stagger -tuned video i.f. amplifier, except A.G.C. B+ VOLTAGE for the Panasonic which uses three. All use 4.5 -mc. inter - sound systems. Most of the major circuit distinctions OI carrier IMPEDANCE lie in the a.g.c. and sweep circuits. CONVERTER The a.g.c. circuit used in the Sony Model 5 -303W (5 -inch set) is shown in Fig. 1A. This fast -acting circuit is designed for 1/1000 of a second operation as opposed to the 1/10- to 1/20- second action of conventional a.g.c. systems. This permits set operation in a moving vehicle where signal level can IF vary at 1 /100 -second rate and also serves to reduce flutter IN caused by passing aircraft. Operation of the circuit is as follows. Transistor Q1 is a 25 -mc. oscillator that cannot oscillate until d.c. voltage is applied to the circuit. The base of this transistor is supplied while the col- with the video signal from the video detector TO 2ND I.F. lector circuit is furnished with a negative -going voltage (rec- (B) tified by D1) supplied from a winding on the horizontal Fig. i. (A) The a.g.c. circuit as used in Sony 5 -inch set. flyback transformer. This action produces relatively noise - (B) Modification of this circuit for use in the 9- incher. free operation since the a.g.c. circuit is only activated (gated) during the horizontal flyback period. The amplitude of the oscillation is dependent on the level of the video signal the base. viDEO appearing at -V A.G.C. The oscillator output is rectified by D2 and applied to the base of d.c. amplifier Q2 through a filter circuit. The time constant of this filter is made very small so that a.g.c. action will be fast. The a.g.c. voltage is applied to the first and A G C. second video i.f. stages. To assist a.g.c. action, a diode is connected in parallel with the primary of the first i.f. transformer to lower the "Q" of this coil when the input level exceeds 10 mv. A variation of this fast -acting a.g.c. circuit is also used in the Sony Model TV9 -304W (9 -inch set) . In this variation, the a.g.c. voltage developed at the emitter of the d.c. amplifier is used to vary the base bias of an impedance converter (see Fig. 1B) that will change the impedance across the collector and emitter circuit. Since the collector of the NEG. PULSE FROM is in series with the emitter HORIE. OUTPUT impedance converter connected TRANS. of the first i.f. stage, the amount of negative feedback applied to the first i.f. stage varies in accordance with the

variations in a.g.c. current. Thus, the gain of the first i.f. (A) (B) stage varies as the input signal level varies. Fig. 2. (A) Gated a.g.c. circuit used in Panasonic 9- incher. Another approach to keyed a.g.c., as used in the Philco (B) The gated a.g.c. circuit as used by Philco in its set. Model 1052 (9 -inch set), is shown in Fig. 2B. In this circuit, the negative -going video signal from the to the a.g.c. output stage Q2 which acts as a d.c. amplifier. first video amplifier is fed to the base of the gated a.g.c. The negative voltage present at the collector of this stage stage Q1. This stage is gated on by the application of a neg- is determined by bucking the "B-" voltage normally pres- ative collector voltage signal supplied from a winding on the ent on the collector by a positive -going voltage generated horizontal flyback transformer T1 and rectifier D1. In this by the negative a.g.c. voltage being applied to the base. Be- fashion, Q1 is permitted to operate only during the horizontal cause the bucking voltage is a function of the video input flyback interval, thus eliminating any noise present during signal level, the a.g.c. voltage will then be a function of the the remainder of the line video signal. The voltage level signal level entering the set's antenna. of the negative signal present on the emitter is governed by The a.g.c. system used in the Panasonic Model "Miley 9" the level of the video signal applied to the base, and the (9-inch set) is shown in Fig. 2A. This peak -keyed a.g.c. sys- setting of the "A.G.C." control. This signal is then applied tem was developed by Matsushita Electric specifically for December, 1964 29

www.americanradiohistory.com and rectified by Q2 and then applied as a.g.c. bias to the EIGHT v.h.f. tuner and the base of the first and second i.f. stages. A diode is connected in parallel with the primary of the first FROM VERT. INTEGRATOR i.f. transformer to compensate for changes in the coil "Q" due to changes in a.g.c. bias. When a positive a.g.c. bias voltage is applied to the base of the i.f. stage, the transistor input and output impedance becomes greater because the emitter current decreases. The "Q" of the transformer becomes greater, resulting in a sharper, more peaked response curve. The diode across the transformer primary provides "Q" damping as the voltage across it is varied with signal strength. With low voltages, such as found in weak signal areas, the response curve will be more (although VERT peaked the bandwidth narrows somewhat), while LIN in relatively strong signal areas the response curve will broaden out (while the over -all gain decreases) . One of the interesting circuits used in the Delmonico VERT. HOLD Model 4T -40 -UHF (4 -inch) TV set is the vertical deflection circuit shown in Fig. 3. The circuit is very similar to a high -quality audio amplifier with a special feedback network. Transistors Q2, Q3, and Fig. 3. Delmonico's vertical output stage is a high -qua ity Q4 operate as a current amplifier, similar to an audio am- audio amplifier with feedback making it into an integrator. plifier. The special feedback networks convert this amplifier into an integrator circuit. The output of this constant -cur- 70 VIDEO AMP. -70V rent integrator is fed to Q1 so as to control the signal. The E.H.T. signal applied to the vertical yoke is an exceptionally linear TO FOCUS saw -tooth and very efficiently in this class B output ELEMENT operates circuit. FROM HORIZ. Although there are some differences between sets, Fig. 4 OSC. AND HORIZ. DRIVER YOKE shows a typical horizontal output stage. This particular cir- OUTPUT TRANS. cuit is used in the Sharp Model TRP -602 (6 -inch set). TO HORIZ AFC. Although not shown in the circuit, an a.f.c.- controlled AND KEYED A.G.C. 12V blocking oscillator is used to generate the line frequency. Fig. 4. The horizontal output stage as used in the Sharp set is is typical of those used in many other transistorized sets. This signal fed through a driver stage to the horizontal output circuit shown in Fig. 4. use in this particular model of their transistor TV sets. The output of this typical stage serves many purposes: it The video signal is supplied to Q1 through diode Dl, with is used to supply the horizontal portion of the deflection the voltage appearing across Cl having the peak value of the yoke with the horizontal sweep signal (with suitable damp- horizontal sync signal. A negative -going pulse from the hori- ing) ; the horizontal pulse at the collector is also rectified zontal output transformer ( greater than 12 volts), clipped and filtered to generate the relatively high `B +" voltage re- by D2, is applied to the emitter of Q1 through Rl. quired by the video amplifier; the horizontal pulse drives a The voltage waveform at the collector of Q1 is amplified transformer that generates (Continued on page 69)

Characteristics of the portable TV sets shown on the cover. These are typical of most sets found in today's market

GENERAL Name DELMONICO SONY SHARP REALTONE PHILCO PANASONIC ELECTRIC Micro -TV Model 4T -40 UHF* TRP-602 TR -6867 TR -805 1052 Mitey 9 5 -303W Screen Size 41/2 5 6 6 9 9 9 (inches)

Set Dimensions 43/e x 85/8 41/4 x 75/8 51/e x 81/4 51/2 X 101/4 91/4 X 101/2 10 x 9 73/4 x 9 (inches) X 87/a x 71/4 x 7346 x 81/2 X 93/4 x 9 x 83/4

Set Weight 8 81/2 9.9 10 13 103/4 101/2 (pounds) self- contained external external external external external external Power Sources 12 -v. battery: 12 -v. battery: 12 -v. battery: 12 -v. battery: 12 -v. battery: 12 -v. battery: 12 -v. battery: 117 -v. a.c. 117 -v. a.c. 117 -v. a.c. 117 -v. a.c. 117 -v. a.c. 117 -v. a.c. 117 -v. a.c. d.c. Power Consumption d.c. -3.5 d.c. -9.6 d.c. -10 12 d.c. -12 -11 9.5 (watts) a.c. -5 a.c. -13 a.c. -18 a.c. -30 a.c. -17

Operating Time Per 4 8 4 4 4 4 5 Battery Charge (hours) Transistors 28 25 24 25 24 27 27 Diodes 32 20 17 27 17 15 20 Size Speaker 21/2 3 31/8 3 4 x 21/2 31/2 4 x 21/2 (inches) Sound Output Power 200 150 200 200 200 250 200 (milliwatts) Telescopic Telescopic Telescopic Telescopic Telescopic Telescopic Telescopic Antenna monopole monopole: monopole: dipole monopole monopole u.h.f. loop u.h.f. loop monopole

Picture I.F. 26.75 26.75 26.75 45.75 45.75 45.75 45.75 (mc.) I.F. Sound 22.25 22.25 22.25 41.25 41.25 41.25 41.25 (mc.)

All sets hare provisions for ea .phones. All can use external antennas. All can be operated from 12 -r. car batteries. *Distributed by Allied Radio as 24SC343 -R. 30 ELECTRONICS WORLD

www.americanradiohistory.com CAPACITANCE NOMOGRAM Relation among capacitance, voltage, stored charge, and amount of energy available upon discharge of capacitor.

By FRANK D. GROSS

IERE is a nomogram relating the capacitance of a two known values, and then read out the unknown values. capacitor (C), the voltage across its terminals (V), Example 1. A 2 -1.f. capacitor is charged to 25 volts. What the stored charge (Q), and the available energy if is the charge and the stored energy? The intersection point is . the capacitor discharged (W) It is optimized about C=1 between C=2 µf. and V=25 volts is found ( point A) . The µf. This allows the nomogram to cover most of the capacitor charge is then read vertically downward and is seen to be values normally encountered in timing circuits, SCR firing 50 microcoulombs. The stored energy is between the 500 - circuits, and pulse -forming networks. V is in volts. Q, the and 1000 -microjoule lines and is nearer to the 500 line. In- stored charge, is microcoulombs; and W, the energy, is in terpolation will give a value of 625 microjoules. microjoules. Example 2. An SCR needs 1000 microjoules of energy to The basis for the nomogram are two capacitor equations: insure firing. A capacitor charging voltage of 30 volts is avail- Q=C x V and W= Q x V x ,'z. (Note: By substituting (C x V) able. What is the minimum value of capacitance that can for Q in the second formula, we obtain the more familiar W= provide this energy? The intersection between the W=1000 (CxV) xVx1 =3 CV-.) and V=30 is found (point B) . Although this is close to the Knowing any two of the variables lets a solution for the C=2 µf. line, 2 µf. is not quite enough to provide this energy. other two to be found. A value closer to 2.23 id. or 3 µf. would have to be chosen for To use the nomogram, find the point of intersection of the this particular application.

loo

C) 50 J O 40

C=3)_iF 30

10 C-IOIJF

10 20 30 40 50 60 70 80 90 100 MICROCOULOMBS (Q)

December, 1964 31

www.americanradiohistory.com RECENT DEVELOPMENTS in ELECTRONICS Airlines Reservations Computer. Ninety separate pieces of equipment making up American Airlines' "Sabre" reservations system are shown in this photo made at the airline's electronic reservations center at Briarcliff Manor, N.X. Built by IBM for $30.5 million, "Sabre" is the largest commercial real -time data -processing system in operation. Each agent at the airlines' nationwide offices has a desk -size console that permits direct communications with the center. Receipt of each of the many reservations queries is acknowledgec within seconds.

Laser Range Finder. Eight laser range finders, recently Automatic Fault Finder. A new Air Force fault locater that is delivered to the U.S. Army, are among the first military able to automatically check out airborne equipment is shown devices using lasers to be produced in this country. Here being operated above. The device cuts manual checkout time one of the RCA -built units is shown being tested in the from several hours to a few minutes, and actually prints out any field. The major advantage of such light- pulsing laser needed repair instructions on an electric typewriter. The heart devices for the military is rapid high accuracy from a of the unit, built by Sperry, is a digital computer in which is single location with a degree of security not obtainable stored over 500 different instructions to make the necessary with radar devices. The pulsing device, called a "Q- electrical connections and measurements through cabling from spoiler," is a rotating mirror which causes the laser to fire its small trailer. The computer will order signal generators, also when the plane of the mirror becomes perpendicular to mounted in the trailer, to simulate the full range of electronic the longitudinal axis of the ruby laser rod. Range is ob- signals that the airborne system would actually experience tained by measuring travel time of the light pulses. in flight. Signals can be varied to fit any checkout routine.

32 ELECTRONICS WORLD

www.americanradiohistory.com Tacan Antenna Test. A Tacan (tactical air navigation) antenna Laser Retina Welder. Light beam from a laser retina is shown being tested in an r.f. anechoic chamber which re- welder, developed by Honeywell, is aimed by holding duces radio- frequency reflections to a minimum. The antenna, compact ophthalmoscope-like instrument to doctor's eye. supplied by International Telephone and Telegraph Corp., is Index finger rotates focusing disc correcting for myopic part of the FAA common air -navigation system being established or hyperopic errors. Knurled handle top (above finger) through the United States and Allied nations for point -to -point selects proper beam energy. Thumb button fires 500- guidance of military and civil aircraft. The company was re- microsecond burst of laser light into the patient's eye, cently awarded a $3.5 million contract for a number of antennas. welding the torn retina by means of the heat scars.

Rectangular 25 -inch Color Tube. The picture tube at the right is one of the new, shorter 25 -inch rectangular color -TV picture tubes moving on an overhead conveyer at the RCA plant in Lan- Microelectronic Frequency Synthesizer. A comparison between caster, Penna. Samples of the new tube were delivered to the a conventional frequency synthesizer using printed circuits nation's color -TV set makers recently. At the left is the 21- and a compact synthesizer using microelectronic techniques inch, round color tube which is expected to provide the bulk gives graphic evidence of what miniaturization can accomplish. of color -set sales for the year 1965. The new tube wi,l be com- The small, square thin -film wafer in front of the circuit board mercially available in limited quantities at a price of $152.50 o` the miniature synthesizer indicates the size reduction pos- with the price being reduced to no more than $130 by the first stle. The compact synthesizers, built by Collins, are for use of the year. The round tube currently sells to manufacturers for in portable field communications pack sets. The circuits op- $89.50 for a non -laminated tube and $98 for a laminated tube erate at a frequency of 40 mc. with a power consumption of with glare -free safety window. Also being worked on by the 4 only milliwatts. The unit consists of 410 semiconductor com- company is a 19 -inch, 90- degree rectangular color tube. Over- ponents and utilizes 33 thin -film circuits. Providing 1 -kc. all length ct the new tube is just under 21 inches, which repre- channel spacing, stability is said to be one part in one million. sents a 41 -inch reduction over the standard 70- degree tube.

December, 1964 33

www.americanradiohistory.com Transistorized FM- STEREO DEMODULATOR

By J. W. ENGLUND, L. PLUS & H. A. HANSEN / Radio Corporation of America

Design of a multiplex adapter, using inexpensive transistors, which features noise immunity and automatic mode switching.

OST commercially available stereo demodulators that conducts and opens the subcarrier -regenerating stages. The employ automatic switching function properly with amplified signal appearing across R5 is added to the L3 sec- high signal levels and in the absence of noise. How- ondary voltage to form the input signal for Q5. Therefore, forward bias to Q2 increases substantially and 1ever, when an FI 1 tuner is tuned to a weak station, or be- the developed tween stations, any attendant noise is filtered and amplified biases Q2 to optimum operating point and gain. in the stereo demodulator and switches the demodulator The operating point of Q2 remains fairly constant with to stereo operation. Because the signal -to -noise ratio of stereo pilot -level variation at the input to the adapter because the reception is 23 (lb worse than that for monophonic reception, bias for Q2 is a function of both the pilot level at the input such erroneous switching of the demodulator results in a sub- to Q5 and the amplified pilot signal developed across R5 by stantial degradation of the receiver performance. Q2; the amplified pilot signal developed across R5 being rela- This article describes a transistorized stereo demodulator tively insensitive to pilot level changes while in limiting. As which utilizes time -share detection, an effective noise -im- a result, when the input pilot level is reduced, Q2 remains munity circuit, as well as a stereo program indicator. in conduction below its "turn on" input pilot level. The amplified 19 -kc. is fed to a balanced full -wave rectifier Circuit Description composed of the secondary of L4 and D2 and D3. The out- is unfiltered and provides frequency Fig. 1 is the schematic diagram and parts list for the time- put of the rectifier circuit share stereo demodulator. This unit uses five transistors and doubling with a d.c. component. The d.c. component turns five point- contact diodes. on Q3, permitting the 38 -kc. signal to be amplified. In addi- in the emitter of Q3 provides drive At the input, C2 and L 1 form a parallel resonant trap which tion, the amplified d.c. provides SCA filtering. This filter produces less deterioration for Q4 and turns on the stereo indicator lamp. Fig. 2 shows in- of the composite signal than a series resonant trap to ground. a modified version of the indicator circuit which uses an Transistor Q1 serves as a pilot separator. The load for the expensive lamp. collector is a double -tuned, top -capacitance -coupled 19 -kc. The 38 -kc. signal from Q3 is applied to the primary of L5, of Q1 is applied transformer (L2, L3, C6) which provides a high degree of and the composite signal from the emitter selectivity for the pilot frequency. In addition, Q1 serves as to the secondary center -tap of L5. When a properly phased an emitter follower for the composite signal. The emitter re- regenerated subcarrier is added to the composite signal, a en- sistor (R4) is partially bypassed by C4 to compensate for 38 -kc. amplitude -modulated signal is formed having one the high -frequency roll -off of the stereo subchannel by the velope of right -channel information and one envelope of D5 SCA filter. This stage provides an input impedance of about left -channel information. Diode D4 and each permit the signal. 15,000 ohms to the composite signal, and prevents excessive passage of only one -half of the two -envelope L8, C20, loading of the FM detector. R21 and C22 form the de- emphasis network. L8 C20 serve The threshold amplifier, together with the 19 -kc. amplifier - and C18 constitute a low -pass filter; and also limiter, comprise the noise- immunity circuit. Transistor Q5 as a trap for the 38 -kc. residual. Matching components are serves as a selective amplifier for the 19 -kc. signal. The unused in the other channel output to perform similar functions. bypassed emitter resistor (R14) raises the input impedance Alignment Procedure of the Q5 stage and minimizes loading of the double -tuned is required: an transformer (L2, L3). Resistor R16 is an isolation resistor be- The following laboratory -type equipment tween the threshold amplifier and the 19 -kc. amplifier- limiter. a.c. vacuum -tube voltmeter; a multiplex stereo generator; a The threshold detector diode (D1) develops forward bias wide-range audio oscillator; a 12 -volt, 25 -ma. d.c. power for horizontal input for Q2. The pilot and regenerated subcarrier is well limited supply; an oscilloscope having provisions FM signal to minimize phase shift over a wide range of pilot levels. Re- and 1 -mc. vertical- amplifier response; and an verse biasing is applied to Q2 through the threshold control generator. specifica- The recommended alignment procedure is outlined below. (R7) ; R6 limits this reverse bias within transistor steps 23 tions. The first 22 steps apply to the demodulator only; At high tuner sensitivity levels or during interstation tuning to 30 to both the demodulator and the tuner. to mid -position. where the noise level is high, the threshold control can be 1. Set threshold potentiometer at both out- adjusted to prevent Q2 from conducting. Since the noise 2. Provide 10,000 -ohm resistive terminations spectrum from the FM detector is wide band, but the pilot puts. 3. to the 12 -volt power supply. channel filtering (L2, L3) and the threshold amplifier chan- Connect the demodulator to of Q1. nel filtering (L6) select only the 19 -kc. portion of this spec- 4. Attach the a.c. v.t.v.m. the emitter 72 input signal to the de- trum, the noise spectrum power is very low at the threshold 5. Apply a 100 -mv. r.m.s. -kc. detector diode compared to even a weak 19 -kc. pilot signal. modulator input. 6. L1 on the v.t.v.m. As a result, the noise -immunity circuit can discriminate be- Tune for null the right output. tween noise and weak pilot signals (as obtained under high 7. Attach the a.c. v.t.v.m. to 8. Feed 38 -kc. signal into point A. tuner sensitivity conditions) . inductor L7. When an acceptable pilot level is reached, the developed 9. Null the meter by tuning forward bias overcomes the pre -set reverse bias; Q2 then 10. Repeat for left output, using L8. ELECTRONICS WORLD 34

www.americanradiohistory.com COMPOSITE INPUT SCA FILTER C6 38 -KC. AMPLIFIER 4 L5 PILOT L2 FREQUENCY 0 3 DOUBLER C2 SEPARATOR I( 19 -KC. AMPLIFIER 3 L4 TYPE o TYPE AND LIMITER o D2 Q3 2N1524 IN295 R9 TYPE 4 3 RII QI C7 á 2N1637 2 02 5 o C8 b 6 ó 0 O 20 IN295 R10 D3 R5

THRESHOLD CONTROL 7 1 o I LAMP SWITCH TYPE 12V 2N406 1N295 THRESHOLD 16 %1 DI AMPLIFIER I PLI L6 IN295 \J TYPE LAMP *1869 D4 2NI524 STEREO PROGRAM R22 Q5/ INDICATOR C12 0oá 0 C14 0 0 R 5 R19 o 6 R23 IN295 R12 R13 L 14 R14 J C19 D5 C15 I R20 RIGHT OUTPUT TC21 R17 _ CI7v L7 Fig. 1. Diagram of FM- stereo multiplex demodulator with noise -immunity circuit. C _L CI8^ _C22 R18 L8 RI- 39.000 ohm, /z w. res. C1 -10 µf., 6 v. elec. capacitor C16 R2 -3900 ohm, t/2 w. res. C2 -560 pf. mica capacitor R3 -4700 ohm, /z w. res. C3 -100 µf., 3 v. elec. capacitor LEFT R21 R4-470 ohm, V2 w. res. C4 -.005 µf. disc ceramic capacitor OUTPUT R5, R14-1000 ohm, 1/2 w. res. C5, C7, C9, C13 -1000 pf. mica capacitor C20 R6 -5600 ohm, '/2 w. res. C5-18 pf. mica capacitor R7- 100,000 ohm pot ( "Threshold Control ") C8, C10, C12, C14 -.05 µf. disc ceramic capacitor R8, R15, R16, R17', R18" R22, R23-10,000 ohm, C11 -390 pf. mica capacitor I/2 w. res. C15, C16-1 1d., 3 v. disc ceramic capacitor L7, L8 -38 kc. trap, 1511 mhy. var. inductor (TRW R9 -2200 ohm, 1/2 w. res. C17, C18 -1600 pf. disc ceramic capacitor 17198 or equiv.) RI0 -1200 ohm, 1/2 w. res. C19, C20 -120 pf. disc ceramic capacitor ± 10% Note: A complete set of eight coils required is R11 -270 ohm, I/2 w. res. C21, C22 -.02 4. disc ceramic capacitor available from TRW Electronic Components Div., R12- 47,000 ohm, Vz w. res. C23, C24 -4700 pf. disc ceramic capacitor 666 Garland Place, Des Plaines, Illinois 60016 at 1613 -8200 ohm, '/2 w. res. Ll -SCA trap, 10 mhy. var. inductor (TRW a price of $15. Individual coils are available at R19-560 ohm, /2 w. res. 14039R1) $2.75 each. R20, R21 -3300 ohm, /2 w. res. L2-19 kc. coil (TRW 15485R3 or equiv.) D1, D2, D3, D4, D5 -IN295 R17 and R18 are to be used if input impedance L3 -19 kc. coil (TRW 15486R3 or equiv.) PL1 -1869 lamp (10 v. C 14 ma.) to stereo amplifiers is considerably higher than L4-19 kc. coil (TRW 15360R9 or equiv.) Ql, Q3, Q5- 2N1524 transistor 10,0(1(1 ohms. If input impedance is lower. these L5 -38 kc. coil (TRW 15361R7 or equiv.) Q2- 2N1637 transistor resistors should be omitted. L6-19 kc. coil (TRW 15759R1 or equiv.) Q4 -2N406 transistor

11. Attach the a.c. v.t.v.m. to TP1. 14. Increase the threshold potentiometer clockwise until 12. Feed a 20 -mv. r.m.s. 19 -kc. pilot into the demodulator the indicator lamp lights. unit from the multiplex stereo generator. 15. Attach the a.c. v.t.v.m. to TP3. 13. Peak L2, L3, and L6. The stereo program indicator 16. Peak L4 and L5. lamp should not light during this step. (If the lamp does light, 17. Reset the threshold potentiometer to mid- position. retard the threshold level by turning the control counter- 18. Connect the audio oscillator to multiplex generator. clockwise until the light extinguishes, and re -peak L2, L3, 19. Apply a 500 -mv. r.m.s. 1 -kc. (L =R) 10% pilot com- and LO. ) posite signal from the (Continued on page 76) 270 38 -KC. AMPLIFIER OHMS COMPOSITE VARIABLE 03 AUDIO SIGNAL FM STEREO DEMODULATOR ELECTRONIC OSCILLATOR GENERATOR FILTERS V.T.V.M. VARIABLE UNDER ATTENUATOR TEST L L o j0 R LAMP No.49 1200 OHMS V.T.V.M.

LAMP 2V SWITCH 60MA. Fig. 2. Modification of lamp switch circuit to permit the SCOPE OHMS TRIGGER use of an inexpensive lamp. PHASE -SHIFT V1 NETWORK Fig. 3. Test setup a 560 OHMS IN TO V2 that was employed -3 VOLT SUPPLY ORIGINAL CIRCUIT VERT CAPABLE OF DELIVERING for 60 MA.FOR INDICATOR LAMP channel separa- HORIZ. SYNC tion measurements. December, 1964 35

www.americanradiohistory.com USING HOOK -UP WIRE

By JOSEPH TARTAS

There is a lot more to a piece of wire than is visible. It can act as an inductor, resistor, capacitor, or tuned circuit, depending on how and where used, and at what frequency.

HOOKUP wire, as used in conventional electronic cir- these requirements, there are plastic, Teflon. silicone, glass, cuits, is a slender length of copper usually insulated fiberglass, epoxy, and many other combinations. with a coating of non- conductive enamel or other For the technician, experimenter, and amateur, enameled insulating material. However, take that same piece of wire and Formvar wire are most commonly used. "Formex" is a and bend it, coil it, or place it near an electrical ground, tradename for one brand of Formvar. The difference between magnetic field, or metallic surface, or allow an electric cur- enamel and Formvar is that the latter is a tough, durable, rent to flow through it, and you no longer have "a piece of varnish -type resin -base insulation. It is not as easy to scratch wire." Change its temperature and you change its physical or nick, nor will it peel off when making a sharp bend in the and electrical constants. Add or change its insulating cover wire, as will enamel. While it may be removed by scraping, material and the chances are you've changed one or more of like enamel, a chemical stripper is available to remove the its physical, electrical, or magnetic characteristics. coating without danger of nicking or damaging the wire it- At d.c. and audio frequencies, the characteristics of major self. When using a chemical stripper, observe the precautions concern are resistivity and power dissipation. The resistivity on the container. If you splash it on your skin, it must be depends entirely on the cross -sectional area and the type of washed off at once or it will cause a minor burn. material used in the wire. Because resistivity can vary widely, Audio & Ultrasonic Frequencies the selection of the conductor is usually determined by the end use. The term "conductor" thus becomes a fairly flexible We are familiar with the effects of 60 -cycle bum pickup. word. Nichrome resistance wire used in appliance heating This usually results from the presence of a mire as a con- elements is a conductor with a high resistance, and can be ductor (even though it is at a d.c around potential) in a referred to by either term. It is, however, still a wire. It is changing magnetic field. Another cause may be the flow of a sometimes difficult to remember the basics, and the resistance heavy a.c. current, such as in a tube filament return or in relation of larger diameter conductors is one of these. What a ground bus wire. In the former case, the fluctuating a.c. happens to the resistance if the diameter is doubled? If we current is induced in the finite, though low value. inductance picture a length of conductor or resistor split into four quad- by the changing magnetic field around the wire and, in the rants, with each having the same resistance, the total length latter case, by the finite, though low value, resistance in this resistance is then the same as if we put the four resistors in short length of wire. In both cases, the a.c. voltage that re- i.e., parallel or ',1 the resistance of one unit. Since the current is sults is in accordance with the very basics of electricity, the same in each unit, then the total current is four times as a changing magnetic field causes a current to flow in the great as a single unit. Because the resistance is the same in inductance (hence induction) and a current flowing through each unit, then the voltage drop across each must be exactly a resistance causes a difference of potential across that re- the same as one, and the power dissipated must be four times sistance (according to Ohm's law). as great, since the current in each one has not increased. Radio Frequencies Since most conductors or wires commonly used have round cross -sections, the area is always a "circular mil" area rather As we go higher in frequency, several other effects occur. than a square area. A circular mil is the square of the diam- A piece of wire is no longer a piece of wire and a resistor eter in mils. (A mil is 1 /1000 of an inch, or .001 ".) or capacitor is no longer just a resistor or capacitor because One advantage of knowing wire diameter in mils is to fa- it also has wire leads. As a result, a resistor (Fig. 1A) appears cilitate the determination of number of turns -per -inch for alternately as a resistor, an inductance, or an inductance in coil winding. The number of turns is simply the reciprocal series with a resistor (depending upon the resistance value), of the wire diameter (in inches), or 1000 divided by the wire an equivalent resistor, or a capacitor, with the changes oc- diameter in mils. curring with the continually increasing frequency. It should be mentioned that most wire tables are based A capacitor, Fig. 1B, appears alternately as a capacitor on bare wire dimensions. For enamel, single Formex or Form - with a negligible series resistance, a series combination of ap- var (E) (SF) insulation add 1 mil to the diameter; for single capacity and resistance ( as the capacitive reactance silk, double Formex or Formvar (SSC) (HF) add 2 mils; proaches the resistance), a low resistance in series with a is for single cotton (SCC) add 4 mils; for double cotton (DSC ) series -resonant circuit, which in effect a higher resistance, X,. small add 8 mils, and for silk- covered enamel (SCE) add 3 mils. and a high -impedance inductive circuit when gets In the past decade, many new insulating materials have and X,, gets large. been developed. However, the selection of insulated wire de- In Fig. 1C, an inductance is similar to a resistor. except pends upon such requirements as temperature range; expo- that the resistance value is high for the resistor and relatively sure to weather, chemicals, or abrasion; voltage between turns low for the inductor. The important fact here ( and its rela- or layers; corona effects; and other characteristics. To meet tion to our main subject) is that in an inductor, the inherent 36 ELECTRONICS WORLD

www.americanradiohistory.com inductance is intentional, while for the resistor and capacitor, HIGH FRED. the inductance that is present is purely a part of the physical BELOW RESONANCE OC. ANO AT ABOVE FRED. structure and is unavoidable. LOW RESONANCE RESONANCE Even the resistance of a wire is a relative thing. At higher HE-- frequencies the to 2= 4711-- 2 =REQUIV. Z =X currents tend travel closer to the surface XLZO XC »XL X,. XL XC «XL and eddy current losses increase beneath the surface. This 1- R %L REOUrv.- q « is the so -called "r.f. or skin resistance." At higher frequencies, (A) a copper tube is a better conductor of r.f. than a solid con- 1/2L 1/2L -(I 6b01-- ductor, and silver plating helps if its thickness is adequate. 1E'VV" - """ -°°..°- 2=X_ Z= R2+%c2 Z. )(LA Wire size is not always the answer, contrary to common be- ZSCLR0 XL=O XC» XL lief (i.e., the larger the diameter, the higher the coil "Q," or Xa= XL XL» Xo XC» R .1R lower the r.f. resistance). There is an optimum size of wire 6c XC « Xco (e) for each coil configuration, not necessarily the largest diameter. The depth of penetration or minimum depth of a con- -t000-^AAMn- .-MXAMA- -I H. Z=R REOU,. %c «XL ductive coating varies with the resistivity of the conducting XLZO XC=XL Z-XC material, as shown in Fig. 2. There are times when it is OC ZOO Z=XL IwRl2 XL «XC RECUrv.= necessary to use poorer conductor materials to reduce gal- ROO vanic corrosion (such as on antennas, or in marine equip- (c) ment) with a compensating increase in skin thickness. Fig. 1. (Al Shows the various "looks" of a resistor at different frequencies while (B) and IC) show similar effects At the lower frequencies (0.3 to 3 mc.) , the use of Litz produced by a typical capacitor and inductor respectively. wire, consisting of many fine wire strands, is common to minimize the r.f. resistance. However, as the frequency in- the G -E 7077 ceramic triode has such low internal reactances creases, the d.c. resistance of the wire becomes the greater that it is possible to build an amplifier at 1000 mc., using part of the resistance and the required wire size then be- a wire loop as a coil and a tubular trimmer as the tuning comes too great to be practical. Insulation losses with in- capacitance, with this tube. Without such a tube, tuned lines creasing frequency also become prohibitive. or coaxial cavities would be necessary. In order to properly select the correct conducting mate- Since such a tube will function well as an amplifier, it rials, the relative resistance of the metals shown in Fig. 2 and is not difficult to utilize it as an oscillator and thus a signal the position of these metals in the galvanic series table must generator or grid -dip oscillator in the 900 to 1000 mc. range be considered. is quite a simple matter. Metals that are close in together the galvanic series are Of course, circuits of this type require the use of high - least likely to corrode, with the lower end of the series as frequency techniques and this brings us to the utilization noble metals (those that tend to resist chemical action). of the internal inductance of a component to improve its Because of its cost, availability, low resistivity (only silver high- frequency characteristics. is lower), and ease of handling, copper is by far the most A 1000 -pf. bypass capacitor (often used above 10 -15 mc.) popular and convenient conductor material, with aluminum may be found in any of a dozen configurations. There are running a close second in high -tension lines and heavy motor mica, Mfylar, paper foil, and several ceramic styles. In the and transformer applications. A straight wire has inductance, although it is insignificant Fig. 2. The r.f. penetration below 10 or 15 mc. Above that, (skin resistance) of various met- the small inductance be- als changes with frequency of operation. At the higher fre- comes an increasing portion of the resonating inductance in quencies, a thin coating of silver is all that is required. combination with stray capacities, and must be taken into los u ISrtiOtasM®tMariatst:®rmraINENImtaraMO aaaaL Oa consideration when selecting components, bus -wire sizes and mvaM `Stio®OOI0000100111111`111OOSMossm11111M1C00 lengths, and best layout of circuitry. CCO1\ \\\\OCI111111111®1111111111111111111CCOO The inductance of a wire is AIII\ \01i11®N11111111111111111 dependent on its diameter and 11111 length and may be computed from the formula: L (µhy.) _ Vi111111M0i111i 1- i 1 11111111 0.00508 1 (2.303 logs ± 0.75) reaching a maximum value so \\ liumm II 1111 \ i as frequency increases of L (shy.) = 0.0058 l (2.303 logic, 111111111111i ER 41 a11 7-1) where /=- length (in inches) and d= diameter (in .111111mono 1111111 IIIIItiO00 - raamxa tamnataaa OfGtaitO1.4 t0tititi inches) . t000 oMItENIBLao MUM= In r.f. wiring it is customary to use a wiring layout that 111COt®v . v:1110tn11M11 MIIIIII1111100 keeps r.f. connections to a minimum and, in the u.h.f. region, 11111II=11111 \\[Ii\IILI 1111111II 111111111111 . 11111 connections are usually made by means of the components themselves, or with short heavy copper straps. Even these gilimmilpriena have some inductance, although extremely small. However, \! 1 at these frequencies even this small inductance is of signifi- 11i1®!S\11 cant value and often forms, along with the stray or lumped 1111111i111iMIN11 circuit capacities, a resonant circuit. Often as not, such a circuit occurs .11111®vI19111lrantiMtmSOMMatsto0.a1 when least desirable-within a vacuum -tube mnEIIIIIs®MIIIHIIMMIIIIIIMMIIIItaa structure, a circuit component, or connecting leads. Some- IICOCO111OCI®11111CMtUsOO®OUti\® times this resonance can be a nuisance by causing - \\ high _MMIIwU5E Ii1 frequency oscillations in a relatively low -frequency amplifier. Other times, the resonance can be put to use as a more perfect r.f. bypass. ÌÌI111s1I1®I®ie11111111Blli If the frequency of operation is quite high, the internal 1111=!111! inductance then becomes part of the total inductance, since 191111iMIiIINál the two are in series. At frequencies where the external inductance is practically zero, a tube with less internal induct- 1du mIi111 ance, capacitance, 0.05 0.1° 0.2 0.5 0.7 I.o 2 5 7 or both must be substituted. A like tube DEPTH -MILS December, 1964 37

www.americanradiohistory.com BUS WIRE when the tuning capacitor is connected directly across the coil with minimum lead lengths. Here, the coil inductance alone determines the resonant frequency of the combination. 21 colt _ The series impedance of the bypass and its associated leads Bus TUNING WIRE lowers the r.f. voltage available to the tube. LEAD COIL LEAD If a bypass capacitor is selected in such a way that the LEAD BUS WIRE TUBE TERMINAL capacity and leads (total from coil to ground) form a series BYPASS BYPASS resonant circuit at the same frequency as the parallel tuned TUNING TUNING to COIL C circuit, then it forms the lowest possible impedance LEAD i*LEAD ground as shown in Fig. 3C. Since the series resonant fre- SERIES - RESONANT t_ is almost identical to the parallel frequency when the T BYPASS quency resonant "Q" is not too low (10 or above), the adjustment (A) (B) (C) of such a circuit is. simple. Fig. 3. (A) Tuned circuit equivalent when tuning capacitor If the leads are cut to the approximate length at which is directly across the coil. (B) A parallel not connected ends are soldered together, a tuned circuit showing effects of bypass leads as series im- they are to be used, and the pedance. (C) Series-resonant bypass produces no ill effects. parallel- resonant circuit is then formed. It is simple to couple this to is grid -dip oscillator and measure this frequency. If its resonant frequency is too high, it may be lowered by selecting a higher value of capacitance or increasing the length El LESS THAN 2MV. of one or both leads. The inductance of the leads may be TO IOMV. 111111 2 further increased by coiling them, making sure that adjacent 010 TO 20MV. turns do not become shorted. When the proper frequency has been attained, install the ®20 TO 100 MV. capacitor in such a way that a minimum of additional stray 100 TO 200MV. inductance or capacitance results. This means adequate space MOVER 200MV. between the component and an adjacent shield, chassis, or other component. Once it has been installed in the circuit, it may be adjusted to the exact frequency without too much Fig. 4. Typical chassis potential levels difficulty. It is surprisingly simple to couple the grid -dip at a specified frequency shows how level oscillator to such a tuned circuit, but care must be taken to reduces towards the actual ground. insure coupling to the correct resonant circuit, since at these ceramic types are found disc, screw -in and threaded -mount frequencies there are usually several. stand- feedthroughs, filter types that use lossy ferrite sleeves, Grounds Can Be "Inductances" off types, tubulars, and others. For each style there is a different body length and a different method of attaching its A final word of caution in visualizing the relation of con- leads. Each of these physical characteristics affects the total ductors and inductances at the higher frequencies. Since series inductance which, with the capacitance of the body, r.f. currents travel through the chassis, shield partion, or form a series-resonant circuit. ground lug, it is quite possible to have coupling between The resonant frequency of such a capacitor is pretty well circuits in a ground or between ground leads in a component. fixed (for a given value of capacity) but its installed resonant A map of r.f. potentials, made by Collins Radio Co. on a typ- frequency will depend upon the length of the leads, the ical chassis, is shown in Fig. 4. It gives a good indication length of the terminals to which it is attached, and the in- of the various r.f. levels that exist within a supposedly good ductance of the wires that connect these terminals to the ground, where you would normally think that all the r.f. tube elements. This includes internal tube inductance, length voltages would be essentially zero (or less than 2 mv. in of socket terminals, and length of bus wire if the capacitor this case). Note that the best ground is only within a small is terminated at a coil form and the coil is connected to the area around the actual ground connected through a minitnunt socket terminal through a wire. inductance. Component leads to a ground lug may also act as a com- Tuned Circuit Effects mon inductively coupled circuit. Fig. 5 shows two possibili- Fig. 3A shows the equivalent high- frequency circuit of a ties. At (A) the two "grounded" wires are coupled together common tuned circuit and bypass capacitor when the tuning by the common magnetic fields and hence by mutual induct- capacitor is not connected directly across the coil. Note the ance. In (B) the same sort of coupling might exist in a dual added series inductance presented by the component leads bypass capacitor as has been experienced at the higher fre- and associated wiring. Fig. 3B shows the equivalent circuit quencies. Where possible, it is best to use separate bypasses and return each one to its own circuit ground. Fig. 5. IA) Separate leads connected to a ground lug can act Any time you think of a chassis, ground, lugs, ground as (BI and a similar form of coupling a mutual inductance in mind not only r.f. within a dual bypass capacitor can be experienced at higher straps, or conductors in general, keep frequencies. This shows importance of separate ground returns. circuitry, but switching circuits as well, where fast rise of fre- LI L2 times are involved (since these are also functions quency since T =1 /F). A rise time of 0.05 microsecond is equivalent to a switching frequency of 20 mc., a value not too uncommon in today's high -current transistor circuits. -.1,11/ (f The lowest inductance, in the case of the loop, is achieved (A) by placing the fields (from each half) 180° out of phase. in this case, cancellation takes place and the over -all inductance is a minimum. For the twisted leads, such as might 1 - 15 -OH H6-6by-- be found in a tube heater lead, note that the total inductance for a twisted pair is considerably less than a single wire re- turned through the chassis. r The next time you pick up a piece of wire or a component for use at the higher frequencies, think carefully before you (B) wire it in. It may be the reason the device doesn't work.

38 ELECTRONICS WORLD

www.americanradiohistory.com SUBSTITUTING S ilieon for Germanium By WILLIAM O. HAMLIN TRANSISTORS OST transistor users have shown a preference for tor constructions. Note that the usual alloy- junction transis- the germanium transistor ever since its development. tor (A) has a large cross- section which limits its maximum M This popularity can be attributed to habit, famili- frequency. Alloy transistors capable of operating above 15 arity, and the availability of low- priced units. mc. are rare. Making the cross -section narrower, as in the Today, not only are there many different kinds of german- micro -alloy transistor (B), increases the maximum frequency ium transistors from which to choose, but they are facing to hundreds of megacycles. An alloy power transistor is large real competition from the new silicon planar transistors which in both cross- section and area in order to handle high cur- are now available at low prices. In many applications the rents and to remove the heat that is generated. Such a tran- silicon planar device can do a better job and, for this reason, sistor is shown at (C) . Maximum frequency of the alloy you may wish to substitute the newer type for the old in power transistor is below 1 mc. for most inexpensive units. a particular circuit. Replacing one transistor by another can Good or bad performance is only relative to the technology be done in a few simple steps. of the time and the price you pay. The advent of the silicon Fig. 1 diagrams a number of popular germanium transis- planar transistor set up new bases of comparison for the industry. You can judge the relative merits of the two tech- Fig. 1. Popular alloy -junction type germanium transistors. nologies by checking the characteristics in Table 1. The advantages of the silicon planar transistor result from its unique construction. Fig. 2 shows the various internal configurations and packages used for the v.h.f. 2N697, the u.h.f. 2N918, and the epoxy entertainment transistors. The planar chip or die is formed by a series of diffusions through one side only -hence the name "planar." A series of patterns is imposed on the surface by photographic techniques so that diffusions of n and p impurities form microscopic transistors with extreme precision. Ultra- high -frequency types are made in the smallest sizes; lower frequency high -power types are large and mounted so as to allow efficient removal of heat. (A) LOW -FREQUENCY ALLOY- JUNCTION TRANSISTOR

Fig. 2. Construction of the planar -type silicon transistor.

PROTECTIVE SURFACE METALIZED CONTACT?

B E

B E C y 100 MC. 3-WATT SILICON PLANAR TRANSISTOR (B) HIGH -FREQUENCY MICRO -ALLOY TRANSISTOR

B E

900 -MC. SILICON PLANAR TRANSISTOR WITH GROUND LEAD ON CAN

B E

uBICuE (C) ALLOY- JUNCTION POWER TRANSISTOR PLASTIC PACKAGE FOR ENTERTAINMENT TYPES December, 1964 39

www.americanradiohistory.com All silicons can be used for audio irrespective of their maxi- GERMANIUM SILICON mum frequency. In fact, their low leakage allows direct coupling of audio stages without complicated temperature Maximum Temperature 85 °C 200 °C (or compensation and thus a transformer can often be eliminated. (167 °F) more) (392 °F) The planar process lends itself to efficient mass produc- Leakage Current IC to BI tion up to the attachment of the leads and, as a result, the At room temp. 2 pa. 0.002 Ala. price has dropped to a point where silicon planars are com- At S5 °C 1131°F) 16 pa. 0.016 pct. petitive with germanium. Many of the new transistorized TV Voltage IC to El sets utilize the same high- quality planar chips, in low -cost UHF type 15 v. 20 v. molded epoxy, as are placed in metal cans for military use. Other 20 -40 v. 40 -120 v. Some of the recommended types, because they are widely available and reasonably priced, are listed in Table 2. Maximum Frequency 1 mc. to over 60 mc. to 1000 mc. over 1000 mc. Replacement of Transistors Voltage drop as switch 0.3 v. 1 v. transistor types the author Published circuits often utilize @ 100 ma. 'dd 100 ma.* happened to have on hand. You may want to improve performance and reliability, especially in portable and mobile Epitaxial devices available with much lower drops. is easy if gear. The changeover to silicon planar transistors Table 1. Comparison between germanium, silicon signal transistors. you follow these rules: 1. Select a transistor with approximately equal current (a), measured from the emitter while gain for planar units gain to the one being replaced. is usually given as beta 09), measured from the base. ( Note 2. If the silicon transistor has higher amplification, its base that ß is also called h,, and a is called h,,,.) The equations current will have to be reduced. to convert these two parameters are: ß = a/ (1- a) and 3. In most cases silicon transistors have higher frequency a= ß /(ß +1). For example, if a germanium transistor has characteristics than germanium alloy devices, so bandwidth an a listed as 0.98, then ß =0.98/ (1- 0.98) or .98/.02 or 49. will be extended or r.f. performance improved. For v.h.f. ap- The frequency characteristics are also given in several plications, where drift, surface barrier, or micro -alloy devices ways. The frequency at which a becomes 0.7 of its low -fre- are specified, check the maximum frequency characteristics quency value is called fa,, or f,,p. The frequency at which to find a planar device which has an equal or higher ft. 4. The base voltage of the germanium transistor is about Fig. 4. Bias- network changes for replacement of 2N293 'n -p -n' germanium transistor with 2N706 silicon unit in an i.f. stage. 0.4 volt less than the silicon transistor for a given collector current, so a simple calculation is required to establish the proper bias current. (See Fig. 3.) 5. If a lrn -p type is replaced by an n -p -n type, all the voltages are reversed. Most silicon planar transistors are of the n -p -n type. 6. In any new construction or replacement, a final check should be made of collector -to- emitter voltage to see if a bias adjustment is necessary. The comparison of data on one type against another in order to make a sensible solution is often troublesome, especially with older germanium transistors, because different may be used to express the performance of (A) characteristics ORIGINAL CIRCUIT WITH 2N293 the two types. It is not difficult, however, to convert one to the other. Cain for alloy germanium units is frequently given as alpha

Fig. 3. Silicon transistors have somewhat higher VISE values I.O.IOMA. I R2K VeE0.6V. 1.0

E VeIV.

6V. VcE 0.8 ON

= 15V. 20°0 2H697 SILICON V E

i (B) (C) SIMPLIFIED BIAS CIRCUIT 2N706 SILICON TH UNCORRECTED WIT UN 0.6 o Vc +9V. +9V >

I.0.14MA RI RI 0.4 54K 82K IV. ANVC Vat 06V V9t06V. Vt04V m VE0.8 2-43= B E E I I IV. - I Ill v6 V6 4 VB VE + 0.6V. R3 VB-V!E IC R2 R3 RIR2(&C -I) R2 R3 9 10K 240n I-0.6 0.2 10K 470A 24011. RI.10K(1- -I) 1.7 I.1 7M4 t IC I.7MA.1 RIIOKK5.4 54K

(D) (E) RS o 26706 SILICON WITH CORRECTION OF RI 2N706 SILICON WITH CORRECTION OF 20 40 60 80 NEGLECTING BASE CURRENT (NOTE : THESE ARE ESTIMATES ASSUMING THAT IE Ic; I.e. COLLECTOR CURRENT - MILLIAMPERES 40 ELECTRONICS WORLD

www.americanradiohistory.com WATTS DISSIP. MAX. No heat With perfect COLL. D.C. CURRENT A.C. CURRENT f PRIMARY USES TYPE sink heat sink VOLT. GAIN GAIN (mc.) A B C D E

2N696 0.6 2.0 40 40 @ 150 ma. 3 @ 20 Inc.* 60 X X X 2N697 0.6 2.0 40 75 @ 150 ma. 4 @ 20 mc.$ 80 X X X 2N698 0.6 2.0 80 40 @ 150 ma. 3 @ 20 mc.$ 60 X X 2N699 0.6 2.0 80 80 @ 150 ma. 3.5 @ 20 mc.t 70 X X 2N706 0.3 1.0 20 40 @ 10 ma. 4 @ 100 mc.t 400 X X 2N708 0.36 1.2 20 40 @ 10 ma. 4.5 @ 100 mc.t 450 X X

2N718 0.4 1.5 some as 2N697 but with small can X X

2N720 0.4 1.5 same as 2N699 but with small can X

2N1975 0.8 3.0 80 140 @ 50 ma. 38 @ 1 kc. 50 X X 2N1984 0.6 2.0 25 70 @ 1 kc. *, 2 @ 20 mc.$ 40 X X 2N1985 0.6 2.0 25 30 @ 1 kc. *, 2 @ 20 mc.$ 40 X X 2N1986 0.6 2.0 40 150 @ 150 ma. 2 @ 20 mc.$ 40 X X 2N1987 0.6 2.0 40 50 @ 150 ma. 2 @ 20 mc.$ 40 X X 2N1989 0.6 2.0 60 40 @ 30 ma. 2 @ 20 mc.t 40 X X 2N1991* 0.6 2.0 -20 p -n -p complementary to 2N1985 X *Collector current =1 ma.; tcollector current =10 ma.; $collector current =50 ma.; ft= maximum gain- bandwidth. KEY TO USES: A. Small- signal video or r.f. amplifier; B. Small- signal audio- frequency amplifier; C. Low -power r.f. or a.f. oscillator; D. Me- dium -power r.f. or a.f. oscillator and amplifier; E. Medium -power switching -relay substitute, power converters, etc.

Table 2. Important characteristics and applications for readily available silicon diffused "n -p -n" transistors. ß becomes 0.7 of its low- frequency value is called fa, or Here the same procedures are used as for the i.f. stage just f),fe. The frequency at which ß becomes 1 is called ft. One discussed. However, the polarity of the voltage and the can be converted to the other as follows: ground point are changed. Note that the emitter of the cir- f a,..~ (1- a) f at where a is the low- frequency gain and cuit in Fig. 5A is connected to +9 volts through R3. Thus fat,~ßX fa where ß is the low- frequency gain. Also, ft= the collector is a -9 volts when the common point at the 0.85 x fat and ft= ß (at high frequency) x f ( frequency) as lower end of the bias network is the reference, as redrawn can be seen in Table 2. in Fig. 5B. The new n -p -n silicon circuit shown in Fig. 5C As an example, to compare one type of transistor with an- without bias correction has ground at zero potential and the other, consider a 2N1178 germanium drift transistor listed collector at +9 volts. (Continued on page 58) with an a= 0.976 and lab= 140 mc. Fig. 5. Bias network changes for replacement of 2N1415 "p -n -p" fa, = (1- a)fat,= 0.024x140 =3.36 mc., which is fre- the germanium transistor with 2N697 silicon unit in an a.f. stage. quency at which gain (ß) is down 3 db; and f t = 0.85 x 140=119 mc. The replacement should thus have an ft above RI 2N1415 119 mc. A common silicon type, the 2N706, with an ft of 400 4.7K mc. would be more than satisfactory. Bias Adjustment After selecting the planar transistor to be used, the circuit's bias network is adjusted. Two examples, an i.f. and an audio circuit in Figs. 4 and 5, illustrate how this is done. Both circuits have a two -resistor voltage +9V. divider to supply (A) the proper base voltage and an emitter resistor for added ORIGINAL CIRCUIT WITH 2NI415 stability. The example here assumes that the original design gave proper consideration to stability and gain so that a simplified approach may be taken for the silicon substitute. First calculate the bias of the germanium transistor to be II.50M I I.50MA. replaced. Assume that the collector current is the same as the emitter current since any error thus introduced is negligible. If the collector current is known, then simple multiplica- VB-1.5V V. 1.5V. tion of this current by the emitter resistor, R3, gives the emitter voltage. Adding the emitter -base drop of 0.2 volt gives the base voltage. If the collector current is unknown, it can be estimated. In Fig. 4B the total drop of 9 volts across the bleeder R1 plus R2 produces a current of 0.1 ma., establishing the volt- (B) (C) SIMPLIFIED BIAS CIRCUIT 2N697 SILICON WITH UNCORRECTED age at the base as 1 volt. Subtracting the estimated base - BIAS NETWORK emitter voltage of 0.2 volt gives the emitter voltage of 0.8 Vc, 9V. +9V. volt. Then by Ohm's law, this drop across the 470 -ohm emitter resistor results in a current of 1.7 ma. These calculations are approximations, since they consider that the base cur- I1.90MA.? RI I 1.50 MA. RI rent is very small compared to 3.7K 5K the bleeder current. VBE0.7V. VBE0.7V. To substitute the silicon transistor it is only necessary to Vc1.2V. VE0.8V. II II B E change the 0.2 -volt drop to 0.6 volt. Referring to VB 1.9 V. Fig. 4C, VBVE+0.7V. VB I.SV. it can be seen that if the resistance of the bias network is R3VBIVBE R2 R3 RIR2(C -I) R2 R3 C not changed the collector current will drop to 0.85 ma. Fig. IK 100n IK 67n I.5-0.7 4D shows how a lower RIIK (19 -I) 12 6`-n- value of R1 increases the base voltage I.12MA. IC =12MA.1 to RIIK x 3.7 the proper amount to re-establish a collector current of 3 .7 K 1.7 ma. Fig. 4E shows how the emitter resistor, R3, can be changed for the same effect. (D) (E) 2N697 SILICON WITH CORRECTION OF RI 2N697 SILICON WITH CORRECTION R3 The circuit of Fig. 5 is a p-n-p OF medium -power audio stage. (NOTE: THESE ARE ESTIMATES ASSUMING THAT IE lc; i.e. NEGLECTING BASE CURRENT) December, 1964 41

www.americanradiohistory.com Í LYJjy)

Description of some early Edison -effect lamps and oscillation valves developed by Fleming at the beginning of this century.

By PAUL G. WATSON, Cmdr. USNR (Ret.)

TO tell the full story of the beginnings of what we to- a satisfactory filament material, Edison on October 19, 1879 day call "electronics" would involve the writing of lighted the first successful incandescent lamp. It used a several large volumes. The story would begin in the bamboo filament which burned for approximately forty late 1700's and early 1800's when some of the eminent sci- hours, finally going out on October 21, 1879. entists of that day noticed the existence of a "field" around incandescent metal objects. Increased availability of Edison Effect sensitive electrical instruments would play a part and the Duping the winter of 1879 -1880 while experimenting with experimenting with incandescent electric lamps would bring various forms of his lamps, Edison noted the blackening of us to the threshold of our subject, electronics. the inside of the glass envelope surrounding the filament, There was much activity among experimenters in the field increasing in density as the lamp burned. In his notebooks of incandescent electric lamps; the first by an Englishman, dealing with these experiments, dated in February 1880, is De La Rue in 1820, through to Edison in 1879 when the the earliest mention of "carrying current," which we now first practical electric lamp was made. know as "Edison effect." Edison had become aware that more Edison's basic concept of a high -resistance filamentary than light and heat was being emitted from the incandescent lamp enclosed in an evacuated glass envelope solved the filament. problem. After conducting thousands of experiments to find It was found that with a small metal plate or wire within

-4 Fig. 1. Collection of Edison -effect lamps located in the Science Museum, London. Four oscillation valves in the bottom row are a few of the types made in 1905 for Marconi to test. (Photograph: British A D Crown Copyright, Science Museum, London.)

Fig. 2. The Edison -effect lamp which Flem- ing employed in October 1905 to detect wireless signals for the very first time. (Photograph credit: Science Museum, Lon- don, England. British Crown Copyright.)

42 ELECTRONICS WORLD

www.americanradiohistory.com the glass envelope, heating the filament to incandescence pointed electrical adviser to the company. He was thus caused the plate or wire to become charged. When a galva- brought into contact with many of the problems relating to nometer was connected between this plate and the positive incandescent electric lamps. Fleming verified many of Edi- leg of the filament, a flow of current was indicated. When son's experiments and later extended his field beyond that connected to the negative leg of the filament, no current covered by Edison. flowed. Beginning in 1889 and through 1896 Fleming made many This effect, filament emission and the flow of current experimental "Edison -effect lamps" in his study of the phe- through a vacuum to a positive electrode, was the start of nomenon. Some of these lamps can be seen in the Science all modern thermionic devices. \luseum in London. A number of these lamps, used by Flem- Subsequent to these experiments Edison found, while ing in the period between 1889 and 1896, are shown in Figs. evacuating his lamps with a "de- gassing current" warming I and 3. In many cases these lamps have been the subject of the filament, that a blue glow occurred at certain levels of extensive papers presented before a number of scientific vacuum. It was evident that some electrical discharge was groups. passing between the filament legs even though a much lower Of the lamps shown in Fig. 1, A and B are carbon -filament resistance path existed through the filament itself. lamps with metal plates, used in the general verification of Edison never made any practical use of the discovery of the Edison effect. C is a lamp with a platinum filament and either of these phenomena. He did file a patent application a metal plate, used to determine the existence of Edison effect covering their use as "critical voltage indicators" in connec- when using a metal filament. It was found to exist in the tion with his lamps. saule manner as with the carbon filament. D, E, and F were It remained for an English scientist, J. J. Thomson in 1901, used to determine how far the particles from the filament to determine that the emission from the filament, which would travel towards a positively charged plate and whether Edison had discovered, was charges of negative electricity. they could travel around a bend or only in straight lines. Thomson called these "corpuscles, "today we call them "elec- It was found that the current became weaker as the distance trons." Further work in America by O. W. Richardson in this between the filament and the plate increased and was absent same period showed that the "corpuscles" (electrons) were altogether unless the particles could travel in a straight line emitted solely because of their kinetic energy and needed no from the filament to the plate. G and H (also J in Fig. 3) chemical action at the surface of the filament for their release. were used to investigate the emission from various parts of Early in 1881, after the formation of the Edison Electric the filament. The emission vvas shown to be almost zero if Light Company of London, John Ambrose Fleming was ap- the negative leg of the (Continued on page 78)

Fig. 3. Three Edison -effect lamps. "J" has one filament leg screen; "K" has a folded -wire plate; "L" has a metal plate. (Photograph: Marconi copyright. Reproduced by courtesy of the Marconi Company, Ltd., Chelmsford, England.)

Fig. 4. British Marconi Company receiver of the 1912 era, Do- showing the duplicate Fleming "oscillation valves" at the top rear. (Photograph: Marconi copyright. Reproduced courtesy of Marconi Company, Ltd., Chelmsford, England.)

Fig. 5. Three of the "oscillation valves" made in the year 1905 for Dr. J. A. Fleming and employed by Marconi. (Photograph: Marconi copyright. Reproduced by courtesy of the Marconi Company, Ltd., Chelmsford, England.)

December, 1964 43

www.americanradiohistory.com Typical thermal and solid -state electronic time -delay relays. THERMAL RELAYS, THERMISTORS, RC NETWORKS, SCR CIRCUITS, UNIJUNCTION TRANSISTORS - ALL WILL PROVIDE TIME -DELAY OPERATION.

ELECTRONIC TIME -DELAY RELAYS

By LOUIS E. FRENZEL, Jr.

relay is a circuit or device that actu- decreasing the heater current that is required with a se- ates a relay some predetermined time after an initi- ries resistor or else by the cascading of a number of relays. JJI\1EDELAYating signal is applied. These devices are used in a variety of applications requiring the timing and sequencing Thermistors of various operations. Timing problems of many kinds can Another type of thermal time -delay relay uses a thermis- be solved with time -delay relays. tor. A thermistor is a heat -sensitive resistor that has a negative When an engineer turns on the local broadcast transmit- temperature coefficient. When the thermistor is heated, ei- ter, power is first applied to the tube filaments and a time - ther by the surrounding air or by self -heating produced by delay relay. A set time later the relay operates and applies current flow, the resistance decreases. The thermal time lag high voltage to the rectifiers. A time delay is needed to pre- that exists between the application of heat and the change vent damage to the mercury rectifier tubes that must be ade- in resistance can be used to produce a controlled amount of quately heated by their filaments before they can withstand time delay. the high voltage. A typical thermistor time -delay relay is shown in Fig. 1. Time -delay relays are widely used in industrial control When Si is closed, current flows through the thermistor, R1, applications. For example, they are often used to time -se- and the relay but it is not sufficient to cause the relay to quence the operations in a chemical plant. Valves, pumps, operate. The resistance of the thermistor and Rl keeps the conveyor belts, or other devices may be actuated at the cor- current below the relay pull -in value. The current in the rect time by time -delay relays to ensure the proper flow or circuit produces self -heating which causes the thermistor mixture of the chemicals. Other uses are photographic proc- resistance to decrease. This causes the current to increase ess timing, electric welder control, and light flashing. and, in turn, it produces greater self -heating, a lower resistance, Thermal Relays and increased current. This process continues until the current is high enough to operate the relay. When the Many circuits and devices are capable of producing a con- relay operates, the lower set of relay contacts shorts out the trolled time delay, but the most useful and versatile are the thermistor so that it immediately begins to cool. This last thermal and electronic time -delay relays. Of these, the ther- operation also increases the relay current to ensure that it mal time -delay relay is probably the simplest and least locks in until de- energized by opening Si. Delay times from expensive. One type of thermal relay works on the principle several milliseconds to many minutes can be obtained with of metal expansion with heat. A bimetal strip bends when this circuit. heated and makes contact with a fixed strip, thus forming The biggest disadvantage of thermal -delay relays is that a switch. The bending occurs because of the different expan- they cannot be re- cycled rapidly. This means that as soon sion rates of the two metals in the strip. As the temperature as they heat and operate they cannot be de- energized and is raised by a heating element supplied with an electrical used immediately again for the same delay time. Thermal current, one piece of metal in the strip expands faster than lag prevents them from cooling rapidly to their normal sur- the other, and since they are firmly bonded to one another, rounding temperature. bending occurs. It takes a set amount of time for the bi- In the thermistor circuit of Fig. 1, the cooling time is metallic strip to heat and bend so that it touches the fixed minimized by shorting the thermistor with contacts on the contact. This is the delay time, and it is a function of the relay. \Vhen the relay is energized, the lower contact set metals' particular expansion rates and the contact spacing shorts the thermistor preventing current from flowing through that is employed. Fig. 1. Thermal time -delay relay circuit using a thermistor. The time delay is also dependent upon the amount of R voltage applied to the heating element. The greater the volt- per. CONTROL age, the faster the heating and the shorter the time delay. Although d.c., a.c. of any frequency, or pulses can be used for heating, 6.3 -volt, 60 -cps a.c. is the most commonly used source. Heating elements that use 2.5 to 117 volts a.c. arc also available. This type of time -delay relay is capable of producing a fixed delay in the 2 to 180 seconds range. While the tolerance depends upon the amount of delay, it is generally better than 10 %. Longer time delays can be obtained by 44 ELECTRONICS WORLD

www.americanradiohistory.com TO it. It immediately starts to cool and is ready to use again 4 Ebb TO CONTROL in a short time. CONTROL Instantaneous recycle thermal -delay relays similar to the one in the photo are now available for those applications SI requiring it. A standard thermal relay is used with an ex- RELAY RELAY ternal d.p.d.t. magnetic relay in such a way that the total RI R2 1 delay time is the sum of the heating and cooling times. At SCR the end of the delay time, the relay has already cooled and is immediately ready to be used again. OI RC and SCR Circuits Electronic time -delay circuits use the charge or discharge of a capacitor through a resistor controlled by an electron device. A typical arrangement is shown in Fig. 2A. In this (A) (B) circuit the relay is normally inoperative because no plate Fig. 2. (Al RC network in conjunction with vacuum tube pro- current flows through it. The control tube VI is held cut- duces delay. (B) SCR -zener diode circuit provides delay. off by the cathode bias supplied by the zener diode D1. R2 sets the quiescent current level in the zener. When the switch photo at the beginning of this article. These units are the two is closed, capacitor C begins to charge through R1. As soon that are at the extreme right on the previous page. as the voltage across C overcomes the zener bias voltage, Turn -on -off Operation the tube conducts and actuates the relay. /Turn The delay time between the closing of S1 and the actua- All of the time -delay relays discussed thus far are those tion of the relay is a function of the values of R1, R3, C, Ebb, that operate the relay a set time after the circuit is turned and the zener breakdown voltage. Delays of a few million. Another type of time -delay relay operates when power seconds to several minutes are possible. The accuracy is de- is applied and remains on for a predetermined length of time pendent upon the components used, but 10% is easily after which it turns off. A simple way of obtaining this type obtained. This same circuit works quite well with junction of operation is with the circuit of Fig. 3B. When push- transistors, field -effect transistors, thyratrons, and other con- button switch Si is closed, d.c. is applied to the relay which trol devices. actuates immediately. Capacitor Cl charges instantly to the A somewhat similar arrangement using a silicon controlled battery voltage. Switch S1 is opened, but the relay remains rectifier is shown in Fig. 2B. Here again the relay is inopera- on because current is supplied to it by the discharge of Cl. tive because no current flows through it. As soon as S1 closes, The relay remains on until the capacitor discharge current the capacitor begins to charge toward the supply voltage drops below the holding current for the relay. Relay on -time through R1 and the load (the relay coil). When the voltage depends on the relay drop -out current and the time -constant on the capacitor exceeds the zener breakdown voltage, gate RC1, where R is the d.c. resistance of the relay coil. Numer- current flows, turning on the SCR and actuating the relay. ous other circuit arrangements are capable of producing this As in the previous circuit, the time delay is dependent upon mode of operation. the values of R1, C, the supply voltage, and the zener volt- An example of an application for such a relay is the con- age. The advantage of this particular circuit is its ability trol of liquid flow with a valve. A valve operated by an elec- to handle fairly high power loads. trical solenoid could be opened when the relay is first turned on. The liquid would flow through the valve for the delay Monostable Multivibrator time after which the relay would drop out and close the valve. The monostable multivibrator in Fig. 3A makes a good The delay time could be set so that the correct amount of time -delay circuit. In its normal state Q2 is saturated be- fluid would flow. cause of the base current path provided by R,,. The collector It is sometimes necessary to produce time delays shorter output voltage of Q2 is nearly zero; Q1 is cut off. During this or longer than those of which the above circuits are capable. time C charges to V through R,.. When a negative trigger For delays in the microsecond regions and lower, delay lines pulse is applied to the base of Q2 through D1, Q2 cuts off and can be used. Cable, lumped LC, and magnetostrictive delay the collector voltage becomes V,. This applies forward bias to lines are available in a wide range of delays. The mono - the base of Q1, turning it on. C begins to discharge through stable multivibrator of Fig. 3A is also quite capable of micro- R,, and in doing so reverse biases the base of Q2 to prevent second delays. For delay times longer than several minutes, it from conducting. As soon as C has discharged to the point motor -driven switches can be used. Delays up to 100 hours where it no longer keeps Q2 cut off, Q2 conducts and its are possible. The electronic circuits of Fig. 2 can produce collector returns to near ground potential while transistor Q1 delays of several hours if care is taken in design. For highly cuts off. accurate time delays, special types of digital circuitry can The time -delay period is from the start of the trigger pulse be employed. when Q2 is turned off to the time when Q2 turns on. This time is a function of C and Rb, and delays of several milli- Fig. 3. (Al MV delay circuit. (B) Turn -on /turn -off relay. seconds to many seconds are quite possible with good +vcc accuracy. TO The output pulse at the collector of Q2 can be used to CONTROL a 4 control external circuitry or to drive relay. If desired, one SI of the collector load resistors can be replaced by a relay VVVVY o coil. Another arrangement possible is the elimination of the _ D.0 RELAY need for an externally applied trigger pulse and the addition of a pushbutton actuator. These are only a few of the many electronic time -delay circuits possible. Others use the RC charge /discharge char- TRIGGER acteristic controlled by thyratrons, cold -cathode triodes, neon IN lamps, and unijunction transistors. Two commercial time - Tbb delay units using unijunction transistors are shown in the (A) (B) December, 1964 45

www.americanradiohistory.com r,i,E('TRONIC Pli1N'l'ER

A bank of fluorescent lamps, visible in the opening at the right, serves as ultraviolet light source that is employed in this printer to develop the visible image on the paper. By A. W. EDWARDS Century Electronics & Instruments, Inc.

Description of an all -electronic, non - impact type of printer using a special CRT and fiber-optic techniques. THE continued improvement in direct writing (or di- traces appear in very good contrast. The simultaneous ap- rect print) ultraviolet- sensitive papers and the devel- plication of heat (passing the paper over a heated platen, opment of fiber optics have brought techniques of for example) and light greatly accelerates the development high-speed electronic printing into the realm of practicality. of the paper. Latent traces may also be developed by a It is now a routine matter to print desired information at darkroom chemical bath process. rates exceeding 6000 characters per second and to attain The electronic printing system to be described makes use print -out rates of 8100 lines per minute, or more. As further of direct -write paper to achieve the high print rates de- advances are made in the direct -write recording media, even scribed. By the use of a special CRT, one which employs a higher speeds will be achieved. Although presently available direct -write papers are much improved, their reaction times DEFLECTION PLATES remain a principal limiting factor in the capability of the system to be described. CATHODE -RAY TUBE For those not familiar with the technique of direct -write recording, it should perhaps be explained that this is one which utilizes a photosensitive chemical, bonded to a paper base, much as do blueprint papers. The chemicals used are rather like a slow photographic film, except that they react quite fast to the ultraviolet end of the spectrum. J ,-ELECTRON Direct writing has been extensively used in the field of BEAM oscillography. In this service, the ultraviolet source is con- centrated and reflected from small mirrors that are suspended ILLUMINATED on tiny, hermetically sealed coils. Such assemblies are called CHARACTER light -beam galvanometers. These galvanometers are posi- ON CRT FACE tioned in a strong magnetic field. When signals are applied to the galvanometer, the coil is displaced according to the instantaneous signal magnitude and polarity, as the magnetic WRITING CHARACTER ON forces seek to establish an equilibrium. Since the mirror is SURFACE FIBER -OPTIC INSERT physically attached to the coil suspension, this displacement Fig. 1. Special CRT used in the electronic printer described. produces a transverse motion of the incident light ray. The moving ray, focused as a spot on the moving recording fiber -optic bundle insert as an integral part of the CRT face, paper, produces a varying trace which is an analog display the desired characters actually are traced out by signals ap- of the input signal. (See "The Photographic Oscillograph" plied to the deflection plates and control grid. Fig. 1 illus- by Ray A. Shiver in the July 1962 issue.) trates the essential construction of the printing CRT, with its The traces produced by this action are invisible, or latent. fiber -optic insert at the front of the tube. Upon subsequent exposure to mild ultraviolet sources (fluo- The solid rectangular insert is composed of many thou- rescent lamps are universally used) , the paper begins to sands of extremely small (20 microns in cross -section) glass develop. The desired traces represent virtual saturation of rods. These rods are carefully oriented to lie parallel to each the chemical agent; thus, as a slow development occurs other, are fused together, and polished at each end surface. under the influence of weak ultraviolet radiation, the latent Actually, each individual rod is composed of two types of 46 ELECTRONICS WORLD

www.americanradiohistory.com glass, with a different refractive index, but with very similar 3 thermal expansion coefficients. Consider one a tube and the ----'- 78 other a solid rod that fits inside this tube. The type of glass with the lower index of refraction is used for the core and 61 the second type, with the higher refractive index, is the sheath, or outer cover. Light rays incident on the ends of i` MINOR HORIZONTALJ WAVEFORM these rods become trapped in the cores and are transmitted down their length. 2 As may be inferred from Fig. 1, the figures that appear at the writing surface are projections of the trace that is produced by an accurately deflected electron beam. The 41 VERTICAL WAVEFORM unique feature of this CRT is that the back surface of the fiber -optic bundle is actually under the high vacuum of the CRT envelope, just as the deflection plates and other ele- (A) ments are. A type P -11 phosphor is deposited directly on the inside surface of the insert, and the electron beam is adjusted to focus on and sweep across that surface only. The 4 traces produced by the action of the deflecting and blanking 1 23 4 567 8910111213 circuitry are transmitted with negligible light loss to the front, or writing surface, of the optic insert. The major advantages of fiber optics in this application 12 9 are, in fact, the small attenuation of available light transmitted MINOR///_// HORIZONTAL WAVEFORM to the outer writing surface, and the small physical dimensions of the bundle. The design parameters of the rods result in almost no diffraction ( "crosstalk ") between adjacent rods. The bundle used in the electronic printer has a resolution i` VERTICAL///A of approximately 200 photographic lines per millimeter. WAVEFORM These fiber optics are 60 to 80 times more efficient than lens systems of the highest quality, employing the widest (B) aperture lenses available. Additionally, fiber optics are much more compact than any lens system that might be suitable Fig. 3. Composite character generation for (Al numeric and (B) to this printing technique, and further, never require clean- alphanumeric print -out. In both cases the simultaneous application to the CRT plates of the synchronous -deflection wave- ing or lose their adjustment. forms causes the tracing of character elements in the sequence The direct -print paper passes over the outer, or writing, indicated. Discrete characters are formed by selectively un- surface, in contact with it. Thus it is exposed to the light blanking certain segments of this composite figure as required. generated at the phosphor side of the insert. After receiving the transmitted light patterns, the paper issues onward, tain these elements: a special cathode -ray tube and optical is developed by a bank of fluorescent lamps contained in the projection system, a composite character generator, a syn- printer, and emerges as readable copy. chronous unblanking circuit, a decoding matrix, a column This particular printer prints up to 32 columns of data, counter, and a means for paper transport. which data may be read out as either numerals and special System symbols, or as fully alphanumeric print. The latter version Operation has the 26 letters, the ten digits, plus some special symbols Fig. 3 illustrates the composite character traced for both ( " +," " -," etc.). Other models of this printer provide up numeric -only (Fig. 3A) and alphanumeric (Fig. 3B) print- to 64 columns per line, using side -by -side CRT's. In this out. Beside each composite character is a representation of version, the fiber optic inserts are cut on a slant, to enable the vertical and horizontal waveforms that are applied to the writing surfaces to meet in sufficient proximity that no the corresponding CRT plates to produce this entire char- break or gap in the printed line results. acter. The generation of individual letters and numerals avail- Fig. 2 illustrates, in simplified form, the sections of a able in the "electronic font" will be explained in the follow- basic electronic printer. Essentially, the printer must con- ing paragraphs. In operation, the deflection voltages from the composite Fig. 2. Major essential sections shown in block form. character generator are applied ( along with the column counter voltages) repetitively and continuously for every column across the width of each line of print. The beam J from the electron gull, however, is cut off by a voltage from VERT DECODING U NBL ANK ING DATA I J the unblanking generator, applied to the control grid. There- MATRIX GENERATOR HORIZ. fore, until this cut -off voltage is removed (or the CRT un- ILl blanked) there is no beam to be deflected, and no electrons to reach the phosphor and produce light. V CRT N The unblanking circuit serves to remove the cut -off volt- C age selectively from the CRT control grid. When this is done FIBER -OPTIC INSERT COMPOSITE at prescribed intervals of the composite character tracing, CHARACTER only the desired segments of this character are traced on GENERATOR the phosphor, as the electron beam impinges on it. Unblink- ing waveforms for the generation of numerals are shown in Fig. 4. These segment selections are caused by the action of the discrete input codes, and the input data then results in the desired print -out of numbers, letters, symbols, etc. For the generation of the letter "T," only the portions COLUMN > PAPER- ADVANCE of the applied waveform that produced lines 4 and 7 would COUNTER COMMAND be unblanked and a "T" would be printed on the paper in

that column (see Fig. 3B) . December, 1964 47

www.americanradiohistory.com 1. 2 3 4 5 7 Appropriate voltages arë ódticed into the horizontal deflection circuit to advance the trace column by column across the writing surface. Fig. 5 illustrates the voltage waveform for an entire print line. Each "step" is the voltage increase that moves the beam one column's width across the writing surface. The small inset shows the horizontal sweep voltage within the column, as the composite character is traced out. After the entire line is printed, an end -of-line pulse is sent i to the paper advance mechanism, and the horizontal deflection voltage falls to a value representing a return to the opposite side of the writing surface. Current models of the electronic printer employ a stepped motor that advances the paper vertically across the writing surface in increments of one line, on receipt of an electrical pulse command. The stepped motor operation is synchronous with the print cycle, inasmuch as the motor driving impulse is developed by the column counter at the end of each printed line. The particular servomotor employed is easily controlled to operate over a wide speed range. Its action is positive, and response to speed change is instantaneous. The logic level used in the printer is 0 volt = binary 0 and -12 volts = binary 1. For numeric print -out, a 4 -bit binary is required, and for alphanumeric print -out, a 6 -bit binary is required. Special printer driver circuits may be provided to adapt the normal printer input requirements to a wide variety of other data formats. Advantages of Electronic Printing Speed is an expected feature of electronic data manipula- tion, but the ability to achieve rapid, virtually noiseless printing on paper, with the added bonus of high reliability, ensures the electronic printer a bright future in data -handling centers. In such centers, it is imperative that distracting and fatiguing noise be kept to a minimum. Moreover, it is highly desirable that the printer be extremely reliable. Both these goals are successfully approached by the concepts inherent in the design of an all- electronic, non -impact printer. As to noise -and the same factors will apply to wear, vibra- Fig. 4. Unblanking- amplifier outputs for numeric print -out. tion, misadjustment -the mechanical printer inevitably must involve the use of print drums, or type faces (these have weight and require a substantial energy source to fling them back and forth), ribbons, hammers, solenoids, carriage shifts and returns, and other violent start -stop motions. These mechanical motions not only produce noise, and require real power for their actuation, but also severely limit the top data -handling rate. By dispensing with virtually all mechanical contrivances (except for the very straightforward paper advance mechan- Fig. 5. The composite stair -step horizontal - ism), the electronic printer concept eliminates immediately deflection signal. an entire category of potential failures. To name but a few: critical clearances, spring tension adjustments, complex mechanical linkage throws, cam lifts and alignments, friction points, and so on. Not only, then, is the time between failures increased, but the necessity for frequent adjustment and maintenance is largely overcome.

Applications & Future Trends Presently the most active market for these printers is that of the space program, the military activity, and larger industrial applications. Wherever the need exists to accept and display high -speed digital data in alphabetic or numeric form, these devices are "naturals." It may be in "on- line" monitoring of an automated process, or the immediate display of telemetered burst of data from an orbiting space vehicle; whatever the task, these printers maintain a fast pace and their maximum capabilities usually exceed the system requirement. It is only logical that the electronic printer should fall heir to the data -handling chores of a speed -conscious so- ciety.

48 ELECTRONICS WORLD

www.americanradiohistory.com ADVANCES IN PHOTOSENSITIVE _÷ DEVICES

By JOHN R COLL NS

1IOTOELECTRIC devices for opening doors or sound- ing alarms have always been popular Nvith hobbyists and experimenters, and light- actuated mechanisms for counting and sorting products or monitoring processes have enjoyed a significant place in industry for many years. Recent developments have opened up wider areas, however, leading to important new applications in both military and industrial sectors. Major gains have been made in sensitivity, speed of response, spectral range and, in the case of photovoltaic cells, power output. As a by- product, the technician 110W finds a greater selection of sensitive photocells ( Fig. 1) from which to choose when designing circuits. Recent applications of photosensitive devices are far too many to detail, but a few examples will illustrate the scope. Fig. 1. Cadmium -sulphide and cadmium -selenide photoconductive Photocells in mosaic arrangements (Fig. 2) provide a solu- cells are made in many varied shapes by various manufacturers. tion to the problem of high -speed card or tape readers for input to electronic computers. Light impressed on the card or tape passes through to the mosaic where a hole has been punched, illuminating a corresponding photocell. Where Fig. 2. Photoconductor mosaics are often used as tape reader:. there is no hole, the light is blocked. Thus, a pattern corresponding to the information on the tape is transferred to the mosaic. Readers using modern fast -response photocells can now handle 1000 characters per second on tape, or 1000 E!er cards per minute. 111111"y1i1 ('Eli14""lit Photocells operating in the infrared region are used to de- Rft tect fires in enclosed areas of aircraft, such as engines, which are difficult to monitor visually. Their speed and sensitivity are so great that in the case of military aircraft an infrared device will detect an incendiary bullet making a direct hit on a fuel tank and will trigger a detonator which spreads an extinguishing agent through the fuel before the bullet passes through the wing. Overheated journal boxes on freight cars, once a leading cause of melted axles and derailments, used to cost the rail- roads millions of dollars annually. Now, hot -box detectors capable of monitoring the condition of the journal box on each wheel of a freight train traveling 70 miles per hour are installed on each side of the track at check points along the lines. An infrared detector unit generates a pip which is amplified and recorded as each journal box passes it. The height December, 1964 49

www.americanradiohistory.com 100 poses. It is interesting to note that the common incandescent RESPONSE OF HUMAN EYE lamp used for illumination radiates about 90% of its energy 90 in the invisible infrared region. RADIATION OF INCANDESCENT BO Light energy is emitted from a source, such as an incandescent lamp, in tiny packets called photons. The energy of 70 a given photon, expressed in electron volts, is equal to the z u 60 product of the frequency of the light and Planck's constant. Cr W w Since ultraviolet light has a shorter wavelength A, and there- I W a fore a higher frequency than visible light, photons of ultra- N ¢ 2 violet light contain more energy than photons of visible 40 á light. Both ultraviolet and visible -light photons have more zW 30 energy than the infrared -light photons, especially in the far infrared region. The low energy of infrared photons makes 20 detection of the long infrared waves more difficult. 10 Photoconductive Cells

300 400 500 600 700 BOO 1000 Photoconduction dates back to 1873, when it was dis- WAVELENGTH -MILLIMICRONS covered that selenium rods intended to serve as high- resist- Fig. 3. Spectral response of human eye and incandescent lamp. ance elements in apparatus for testing submarine cables decreased in resistance in the presence of light. This action of the pip is proportional to the heat of the box. If it ex- of light on selenium metal is known as intrinsic photoconduc- ceeds a safe limit, a repair is made at the next terminal. tion and is illustrated in Fig. 4A. The outer shell of an atom With modern photocells, it is no longer necessary for an contains electrons which make up the valence band. These intruder to cross an invisible beam in order to be detected. electrons can be raised to the conduction band by absorbing His presence can now be discovered simply from the radiation energy from light. Once in the conduction band, they can given off by his body. Similarly, military infrared equipment take part in current flow, thus reducing the resistivity of the no longer depends on surveying an area which is irradiated material. with infrared light. Passive detectors are now able to pin- The conduction band is separated from the valence band point the location of troops, vehicles, etc., from the normal by the so- called forbidden energy band. It is important to note infrared radiation which they emit. that the amount of energy needed to move an electron across Although photocells that produce output power have been the gap is dependent upon the wavelength of the light, not on known for years and have supplied the energy needed to its intensity. As explained before, the energy of light is great- move the indicator in light meters, it is only recently that they est at the shortest wavelengths. Therefore, if a photoconduc- have become efficient enough to adjust the lens of a camera tive cell were responsive, say, to blue light, it might not react without the aid of a battery. In addition to their use in auto- to even very intense red light. The energy of the red light matically adjusted cameras, cells of this kind are used to would be absorbed and would serve to raise the temperature power small radios or operate tiny motors from energy sup- of the cell but would not cause electrons to jump the for- plied by the sun. Similar types are used to supply power bidden gap if the photons were too weak. However, a violet needed to operate electronic equipment in space satellites. light, since it has a shorter wavelength than blue and there- Characteristics of Light fore photons of greater energy, would cause the cell to react. The forbidden energy gap is different for different mate- According to modern physics, light is an electromagnetic rials, and although practically all materials are susceptible radiation, similar to radio waves but of much shorter wave- to the high -energy photons produced by x -rays, only a length. For this reason, wavelength of light is expressed not comparatively few react to visible light and even fewer to in meters but in microns ( tt) equal to 1 millionth of a meter. infrared. This limitation is overcome, however, by a system Even this unit is rather large, so it is not uncommon to find of doping various compounds with impurities so that the im- wavelengths in either millimicrons (mp. ) equal to 1 thou- purity level is close to the conduction band, as shown in Fig. sandth of a micron, or in Angstroms (A) equal to 1 ten - 4B. This process permits greater sensitivity as well as greater thousandth of a micron. versatility in selection of desired operating range. Fig. 3 shows the optical spectrum in millimicrons, together %N-ith the characteristic response of the average human eye. Cadmium and Lead Salts Note that the shortest wavelength to which the eye responds In the visible region, cadmium -sulfide photoconductive is violet (about 400 mµ) and the longest is red (about 750 cells provide high sensitivity. Their peak sensitivity ranges mp.) , with peak sensitivity in the green /yellow region at from about 51.5 mp. to 615 mp., depending on impurity levels about 550 m ¡.L. Wavelengths shorter than violet and longer and method of treating in fabrication. One type has been de- than red fall into the ultraviolet and infrared regions, respec- vised with peak sensitivity at 550 mµ to match the human tively. Although invisible, they can be detected by photocells, eve. This characteristic is especially useful for light meters, and both regions have been exploited for a variety of pur- cameras, street -lighting switches, and color- measuring equipment. Cadmium- sulfide cells peaking at longer wavelengths Fig. 4. How carriers are generated within a photoconductor. are used in the new automatic dollar -bill changers which (A) Intrinsic photoconductor and (B) doped photoconductor. examine and pass on the authenticity of the paper and ink CONDUCTION before making change. BAND Resistance change with light for cadmium sulfide is relatively linear. A typical response curve is shown in Fig. 5. It has appreciable inertia, however, which slows its response FORBIDDEN IMPURITY LEVEL BAND to changes in light level. Also CdS cells typically exhibit hysteresis effects which cause the resistance vs light characteristics to vary depending on previous exposure. VALENCE '// Faster and more sensitive cells are made from cadmium BAND / AWN selenide (CdSe) which has peak sensitivity in the range from (A) (B) 690 ni . to 735 mµ. Its fast rise time of 1 millisecond from

50 ELECTRONICS WORLD

www.americanradiohistory.com zero to 63% conductance makes it useful for high -speed count- RESISTANCE vs. LIGHT ers and choppers. It is also quite sensitive, its resistance dropping rapidly with even very weak illumination. In the infrared region, various lead salts, usually doped 10,000 n with oxygen. provide extremely sensitive photoconductive cells. The principal types in general use are lead sulfide (PbS) lead selenide (MSc), and lead telluride (We). w 1,000 n The lead salts are usually deposited by vacuum evaporation U in a film about 1 micron thick on a substrate of glass or quartz, á 500 n or they may be chemically deposited. In either case, oxygen is introduced into the process to increase the sensitivity. All three of the lead -salt detectors peak at a wavelength longer ` 100n than 1 it at normal temperatures and, when cooled to about -- 195°C, are useful in the range from 4 to 6 p.. 10n Lead -salt photocells are characteristically more sensitive than the cadmium types discussed before and have shorter A time constants. typical lead -sulfide cell, for example, has a 1 5 10 50 100 time constant of 50 microseconds, while lead- selenide types LIGHT (ft.candles) are available with less 5 time constants than microseconds. Fig. 5. Characteristic response of a cadmium -sulphide cell. Their wide spectral range and fast response have won lead - salt photocells an important place as detectors in military weapons systems. since they are sensitive to the long wave- to these. A transparent resin is then applied for protection. length radiation of warm objects as well as the shorter wave- The manufacturing process for silicon cells is more diffi- lengths of objects which are almost red -hot. cult, resembling the process for making silicon transistors. It is an interesting fact that lead -sulfide cells are widely Purified silicon is melted in quartz crucibles and doped with used in industrial equipment because of their favorable minute amounts of phosphorus, arsenic, or antimony to make characteristics even where sensitivity in the infrared region n -type silicon. An elongated single crystal is grown under is unnecessary. Lead -sulfide cells are used in the card- or carefully controlled conditions from the molten silicon. Slices tape -reader mosaic shown in Fig. 2, which could operate are cut from the crystal which are then ground, lapped, equally well in the visible range. However, its sensitivity cleaned, and placed in an electric furnace where boron is to infrared permits the lamps which supply the source radia- diffused into the outer surface to form a p -n junction. By tion to be operated at a temperature below incandescence nickel- plating and tinning, a thin strip is formed on the for longer service life. Lead -sulfide cells are also commonly p -layer to function as the positive terminal. The n -layer used for motion -picture sound reproduction. serves as the negative terminal. Doped Germanium Silicon photovoltaic cells cover a broad spectral range from about 400 mtt to 1100 mµ, peaking near 800 mµ. Very long infrared wavelengths in the range from 4 to 40 Both silicon and selenium photovoltaic cells may be used microns can be detected by germanium doped with gold or as sources of power for small motors, radios, or to operate zinc. Cold gives the greater response to a signal but cuts off sensitive relays. Where a single cell does not provide enough at about 10 microns. Zinc permits detection at the longer power, several cells may be connected in series or series- wavelengths. In either case, it is necessary to cool the detec- parallel to obtain the necessary output. Fig. 6A shows such tors to cryogenic temperatures to keep thermal energy from a circuit using selenium photovoltaic cells in a relay circuit causing electrons to jump the very small forbidden energy which will throw a switch when exposed to sunlight without gap. Liquid helium must be used for zinc -doped cells. requiring any other source of power. Ordinary glass or quartz will not pass very long waves, so Photovoltaic cells may also be used as photoconductive special vinclows must be used to pass the infrared radiation cells in battery circuits, as shown in Fig. 6B. When employed to the cooled cell. Silicon windows can be used to about 10 , in this way, they require a smaller voltage than is customary but sapphire is needed for the far infrared. These special with photoconductive cells. Where great sensitivity to weak requirements and the attendant expense allow the use of lights is desired, they can be used in the circuit with a tran- doped germanium for only the most important applications. sistor amplifier, as in Fig. GC. Photovoltaic Cells Indium antimonide (InSb) has undergone intense development for production of photovoltaic cells for the far infra- Photovoltaic cells, in which a voltage is generated when red. Cells made of this material have a very small energy gap illuminated, are practically all semiconductor types in which and must be cooled to reduce noise and the spontaneous the active area is a p -n junction. When light is absorbed near generation of carriers as the result of heat. To date, they this junction, new mobile holes (positive charges) and elec- have been of primary interest to the military for advanced trons are released, causing a difference of potential to occur. weapons systems. They can be operated either as photovoltaic Current flows when there is a complete circuit. or photoconductive devices, and they reach peak sensitivity As in the case of photoconductive cells, photovoltaic cells at about 6 microns. will not respond to light of energy insufficient to raise an electron into the conduction band, a factor which is influ- enced primarily by the materials used. Fig. 6. (Al A sun -powe ed relay. (B) A photovoltaic cell used with battery. (Cl Sensitive transistorized photoelectric relay. A popular photovoltaic -cell material is selenium, whose response, like CdS described before, matches the character- 2N535 2N2í4 istics of the human eve. Selenium photovoltaic cells are made by depositing a thin layer of pure selenium on a metal base plate under vacuum, annealing at high temperature to convert to crystalline form, then vacuum depositing cadmium to form the photoelectric junction. An ultra -thin layer of gold may be deposited on the surface to increase conductivity. Terminals, or collector strips, are made of a cadmium alloy applied by spraying, and flexible wire leads may be attached (A) (B) (C)

December, 1964 51

www.americanradiohistory.com IN RECEIVER DESIGN TRENDS FREQUENCY CONTROL I\ gars past, the subject of frequency control for cony By JiM KYLE munications receivers attracted relatively little attention. Operating channels were wide, and as long as the re- The use of digital tuning, frequency synthesis, ceived signal could be tuned in easily and would remain in the receiver's passband, things were satisfactory. When the spectrum generators, stable master oscillators, utmost in stability was required, as for commercial point - continuous transfer systems, and many other to -point communications links, crystal control of receiver techniques in communications receivers in frequency was regarded as the ultimate answer. Today, however, this is no longer the case. Crowding of order to permit precise frequency tuning. the r.f. spectrum by a vastly increased number of users has resulted in the application of advanced modulation systems, requiring the utmost accuracy in receiver frequency control. For reception of single- sideband signals, as an example, re- gaency, which is equivalent to a percentage accuracy of ceiver frequency must be kept within an absolute accuracy of 0.000001%. 50 cycles per second. And if the channel frequency happens Output of this oscillator is fed to a "times -10" multiplier to be in the 8-mc. band, for instance, that means a frequency as shown in Fig. 1, to provide a 10 -kc. source, also accurate accuracy of ±0.000625%. Crystals may be made that accur- to the same precision. The 10 -kc. signal is multiplied by 10, ate, but when such precision is required in combination with again, to obtain a 100 -kc. source, and the process is repeated rapid frequency changes, crystal control may no loner be until high -accuracy frequency sources are obtained at 1, 10, considered to be the ultimate answer. ,uid 100 kc., and 1 and 10 mc. To meet the challenge, design engineers have turned to Signals from each of these five sources then go to harmonic several techniques, most of which are not to be found in the generators, which produce output signals at integral mul- textbooks. The result is that today's frequency control meth- tiples of their input frequencies. Output of the 100 -kc. har- ods are capable of meeting the required precision, while monic generator would be at 100, 200, 300, 400, 500, 600, retaining instant channel-change capabilities and the ability 700, 800, and 900 kc., for example. At the output of each to cover a broad portion of the spectrum. harmonic generator, switchable tuned filters select the de- Digital sired multiple to be passed on to the mixer group. The -Tuning Techniques switches controlling these filters are the front -panel tuning

One of the better -known of these modern techniques is the switches ( see Fig. 2) . "digital- tuning" technique employed by Collins Radio Com- The five stable frequencies selected by the switches then pany on a number of military communications receivers, go to a group of mixers which produce suns and difference some of which are now finding their way into commercial frequencies from their inputs. Only the sum frequencies are and private use. of interest here. For instance, if outputs of 30 kc. and 6 kc_ This technique does away with the familiar timing dial of are chosen from the respective harmonic generators. the the receiver, replacing it with a series of 10- position switches. mixer output would be at both 24 and 36 kc. Other filters, To tune the receiver to a desired frequency, the digits of that ganged to the harmonic- generator filters, reject the 24 -kc. frequency are entered on the switches_ for example, to tune signal and pass on the 36 -kc. frequency. to a frequency of 23.505 me. with the receiver in the In this manner, the digits of the final output frequency AN /ABC -58 radio set, the leftmost switch is rotated imtil desired are selected and added together in such a manner as the digits 2 and :3 appear in the first two windows. The next to obtain that frequency at the output of the final mixer, switch is set to 5, the third to 0, and the final switch to 5. accurate to 0.000001%. This tunes the entire receiver to 23.505 me., with an ac- While this example shows how a single crystal can control curacy of better than 50 cycles either way. hundreds of thousands of output frequencies, the particular The tuning steps may be made as small as desired, giving arrangement chosen to illustrate the point has a serious short- the ability to tune from say, 3 to 30 mc. in 100 -cycle steps. coming in practice. It is almost impossible to filter out all In practice, the smallest step usually used is 1 kc. of the undesired mixer products from such a long mixing The secret of this approach lies in a technique known as chain, with the result that in addition to the desired output "frequency synthesis," by which a signal crystal or a small frequency, several dozen undesired output frequencies are group of crystals may be made to control a large number of also present. oscillator frequencies. The following example, although To overcome this problem, the designer has a choice of crude, gives an idea of this basic technique. two techniques. Both are in use at the present time. The starting point of our example is. a 1 -kc. crystal -con- Spectrum Generator trolled oscillator, which is adjusted to be precisely in step with the NBS station WNW. This assures us an accuracy of Most similar to the basic system is the "spectrum- genera- at least 1 part in a hundred million (10') for our 1 -ke. fre- tor" approach. A spectrum generator uses multiple mixing to

52 ELECTRONICS WORLD

www.americanradiohistory.com eliminate the undesired output frequencies. The desired har- controls are necessary to cover a wide range of r.f. spectrum monics are obtained by a keyed oscillator such as that shown in 1-kc. steps. The problem of rejecting undesired output in Fig. 3, which produces a group of harmonics of the input frequencies is overcome by transferring output to a low fre- reference signal spaced about the normal free -running oscil- quency for filtering, and re- transferring back to the desired lator frequency at which the two triodes would operate in output. The result is simple and dependable operation, yet the absence of the keying circuit. Tuning of this oscillator with the precision required for today's needs. circuit provides the initial adjustment of desired output frequency range. Multiple Crystals Output of this keyed oscillator is then applied to a mixer The other type of frequency synthesis in use at present is as shown in Fig. 4. A stable frequency derived either from known as the -multiple-crystal- technique, and is illustrated additional crystals or from a similar unit operating at lower in Fig. 5. This approach has been used in a number of recent frequency, is applied as the other mixer input. The difference- Citizens Band transceivers and, to a lesser degree, in other frequency output of this mixer is then applied to a narrow - equipment. When covering a limited portion of the r.f. spec- band filter which has a bandwidth chosen so that only one of trum, it is less costly than the single -crystal spectrum -gener- the several dozen output frequencies actually present can pass through. Filter output is applied to a second mixer where 14C. X10 Xi() X10 it is mixed again with the same low- frequency signal applied IOMC. STANDARD MULTIPLIER MULTIPLIER MULTIPLIER to the first mixer. This time the sum -frequency output is used, and it is identical to the desired output harmonic from L --> IMC. the generator. 1 IOOKC. Operation of this type of filter is more easily understood I 10KC. with a numerical example. If the desired output frequency is > IKC. Fig. 1. A series of multipliers 4 2400 kc., and the desired step spacing between output fre- provides desired harmonics. quencies is 1 kc., then the harmonic generator would be RARMONC keyed with output of a 1 -kc. stable reference source, and GENERATORS FILTERS tuned to 2400 -kc. output. Its output would be a spectrum I-10 !KC. KC. %ERS 36KC of frequencies at precise 1 -kc. intervals around 2400 kc., -- KC 30KC 24KC including 6KC 2400.000 kc. 30 FILTER IO .236MC K00 4200MC This output spectrum would be fed to Mixer 1, along with IOKC 4. 164 MC. a second frequency of 1945 kc. The difference- frequency -H h 36KC 36KC. spectrum at the output of Mixer 1 would include frequencies 100- MIXER FILTER á00 of 452, 453, 454, 455, 456, 457, and 458 kc. along with others IOOKC. 200 t42MC extending at 1 -kc. intervals in either direction. -- -. 4.236MC. The 455 -kc. spectrum would go to a 455 -kc. filter having FILTER MC 42MC 34.256MC. 40MC TO RCVR. a total bandwidth of less than 1 kc. A signal at 455 kc. would IMC. MC. -4n 38M. - 200K_ 34.236MC. pass through, but those at 454 and 456, as well as the rest SO.00OMC. 25.764MC. farther removed from the desired frequency, Nvould be 4.2J6MC. 00 blocked. If total bandwidth of this filter is made as great IOMC. MC. 30MC as 500 cps, the low- frequency reference signal could be off MIXER FILTER as much as .500 cps without harming the precision of the output. Fig. 2. Arrangement of harmonic generators, fil ers, and mixers are employed in order to produce the exact fequency required. The 455 -kc. single frequency at the output of the filter

then would go to Mixer 2, to be mixed again with the 1945 -kc. f; f4 TPf

reference. Frequencies present at the output of Mixer 2 WAVEFORM would be 455 kc., 1945 kc., 1490 kc. (difference), and 2400 SPECTRUM SPECTRUM kc. (sum) . A sharp cut -off high -pass output filter would re- OSCILLATOR move the three frequencies below 2000 kc., leaving only the -, TUNINGIt0I 2400 -kc. output. WAVEFORM If the 1945 -kc. signal were not precise, it would make no PRECISIÓN difference to the accuracy of the output, since FREO INPUT f, TUNED this signal TO fl is first subtracted from the input, then added back, and any error cancels out. For instance, if the actual frequency were 1945.2 kc., the output spectrum of the first mixer would be centered around 454.8 kc. instead of around 455 kc. How- ever, the 500 -cycle bandwidth of the filter would still allow the 454.8-kc. component to pass through and when it was subsequently added to the 1945.2 -kc. reference, the output would again be 2400.000 kc. Since any inaccuracies of these "transfer references" do cancel out in this system, usual practice is to employ a group KEYING AMPLIFIER of 10 ordinary crystals rather than to derive these frequencies KEYING COMPONENTS CUTPUT -FREQUENCY OSCILLATOR from the high -precision standard. Fig. 3. A spectrum generator eliminates undesired harmonics. Selection of the next 1 -kc. step is made by changing the Fig. 4. Use of keyed oscillator in frequency synthesis technique. frequency of the transfer reference. For instance, using a 455KC ONLY frequency of 1946 kc. instead of 1945 in our example would NARROW -RAND HIGH -PASS give an output frequency of 2401 kc., since 2400KC. PURE the only com- 1 FILTER SPECTRUM y MIXER ---+! MIXER 2 FILTER --9- 2400KC. ponent of the input spectrum which would produce a 455 -kc. 455 t .SKC 20006C. SIGNAL frequency to pass through the filter would be the 2401 -kc. \452, 453, 454, 455, 456, 2400KC 1945 1 457, 456KC.(AND HIGH- input. Tuning of the keyed oscillator tank circuit selects the ORDER PRODUCTS) 1490 LOW - 455 10 -kc. segment of the spectrum in which operation is desired. FREQUENCY SOURCE Thus with the values used in this example, only two panel 1445KC December, 1964 53

www.americanradiohistory.com ator technique, but its accuracy is inherently limited by frequencies is 26.96.5 mc. To select channel 9 (27.065 mc.), manufacturing tolerances of the ]arger number of precision switch 1 is set to position 2 again hut switch 2 is set to po- crystals required. sition :3. This selects frequencies of 1.5.915 and 11.150 nie. The frequencies shown for crystals in Fig. 5 are chosen to to produce 27.065 me. at the output. produce output on class -D CB channels. They do not neces- The bandpass filter at the output of the single mixer gets sarily reflect the actual frequencies used in any commercial rid of both original crystal frequencies as well as the dif- application of the idea, but are simply to show how it works. ference frequency_. The multiple- crystal technique will produce as many out- The example, as shown, actually produces two "outlaw" put frequencies as the product of the number of crystals used outputs, one at each end of the range, and does not cover at each mixer input; thus with five crystals at input 1, and channel 23. This comes about because the first CB channel five more 2, 2.5 at input output frequencies may be obtained. does not start at the beginning of the natural sequence of 1f both sum and difference output frequencies are used, the channels, and because channel 23 is separated from channel number of possible outputs is doubled. However, in the in- 22 by not 10 or 20 kc., but by 30 kc. Equipment using this terests of simplicity, most applications of this technique technique employ added crystals for coverage of channel 2 :3 restrict to output one or the other but not both. as well, and usually has disabling contacts on the switches To cover the 23 assigned channels of the class -D CB serv- to keep unassigned channels from being selected. ice, a minimum of 10 crystals is necessary. With six at one input and four at the other, 24 output frequencies are avail- Stabilized Master Oscillator able. With five at each input, 25 outputs can be had. How- A technique similar to frequency synthesis in its ability ever, output frequencies other than those allowable for use to control thousands of output frequencies with a single are undesirable, so the setup of Fig. 5 uses six crystals on one crystal is that known as SMO, or stabilized master oscillator. input and four on the other to reduce the number of possible This technique uses a spectrum generator frequency syn- but undesired output frequencies to two. thesizer to produce a precisely controlled output frequency, CB channels progress at 10 -kc. intervals, skipping every but sloes not employ the synthesizer's output directly. in- fifth step, and cover a band approximately 300 -kc. wide. By stead, the synthesizer output is used only as a reference, to selecting the four crystals for input 1 at 10 -kc. spacing, they which the output of a free -running master oscillator is locked select adjacent channels, while the six at input 2 are spaced through a frequency or phase discriminator and a reactance 50 -kc. apart to allow 300 -kc. coverage. modulator. To select a single channel, both switches must be set. For Presence of spurious signals in the synthesizer output is instance, to select channel 1 (26.965 mc.) , switch 1 is set not so harmful in the SMO approach, since no path exists to position 2 and switch 2 to position 1. This selects crystal for the spurious signals to reach the actual oscillator output. frequencies 15.915 of and 11.050 mc. and the sum of these A block diagram of the SMO is shown in Fig. 6; the master oscillator is tuned (by conventional means) to the approximate output frequency desired. A portion of its output (f,) is sampled and applied to a phase detector. The reference signal for the phase detector (f,) comes from the synthesizer. As long as the two signals are identical in frequency 2 S1-2P4T 22 -2P6T and precisely 90 degrees separated in phase, output of the %TALI XTAL2 15.9051 1.050 phase detector will be zero and the system runs free. 19915 MC 1.100 However, should the master oscillator's frequency begin 13...25 1.150 MC. 50 .200 50 15 935 1.250 to drift by so much as a single cycle per second, the phase 1.300 of its signal will also be changing. This change in phase up- COVERS I THROUGH 22 +I OUTLAW AT EACH END sets the balance of the phase detector, producing an output which is positive d.c. voltage for drift in one direction, and negative d.c. voltage for opposite -direction drift.

27MC. The phase -detector output is applied to the reactance BUFFER AMP. modulator, vhich is identical to the frequency -modulator employed in the original F \1 broadcast systems. The output Fig. 5. Mul iple crystals are also employed for frequency synthesis. voltage thus changes the frequency of the master oscillator, Vitt the reactance modulator, and the circuit is so arranged Fig. 6. Simple block diagram of stabilized master oscillator system. that the change is in a direction which opposes the drift. This is a negative- feedback system, and some error signal is always present. It is for this reason that phase rather REACTANCE MASTER OUTPUT than frequency is chosen as the controlled element. Phase MODULATOR OSCILLATOR error call be tolerated, while frequency error cannot. As long as the oscillator is locked by means of the phase A detector, its stability becomes equal to that of the high -precision reference source in the synthesizer. However, since only a single frequency is involved in the locked oscillator itself, no spurious beats can appear in the output. PHASE Because of its complexity, this approach is currently found D.0 CONTROL DETECTOR only ill sophisticated military systems. However, these sys- VOLTAGE tems can be expected to reach the commercial market in the not too distant future, as the straight synthesizer systems have already arrived commercially. Other Techniques Another approach to the problem of maintaining suffi- SYNTHESIZER cient precision while allowing rapid frequency change has been to construct a highly stable conventional receiver to cover a limited portion of the (Continued on page 62)

54 ELECTRONICS WORLD

www.americanradiohistory.com ON OUTSIDE INSIDE MOUNTS 5 WAYS OF HOUSE OF HOUSE

ON MAST

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Constant Isolation between sets ... 22db minimum across all What does all this mean to your customers? Most important, channels (2 -13 and FM) it means that the Super Coupler will not spoil picture resolution Lowest Loss of Any Coupler ... -3.2db maximum by adding smear or halos. The Super Coupler is especially recommended for color installations where preservation of picture Best Impedance Match from Antenna to Coupler and Set to quality is even more critical than on black & white. Coupler What besides performance? Construction and price. The new Allow Best Possible Reception on Color or Black & White Sets Winegard Super Color Couplers have a unique 5 -way mount, sleek new weather -proof coupler housing, pre- notched transmission line There is a wide difference in the performance of TV -FM couplers. outlets. /" slotted Hex terminal screws and no -strip terminal And now, with the new Winegard 2 -set and 4 -set Super Color connections ... the price is only $4.50 for the CC200 which includes Couplers, there is a greater difference than ever. the special inside- outside mount. For example, no resistors are used for isolation of outputs. No Try the new Winegard Super Couplers now and see the differ- resonant coils are used in the circuit. Instead, our research labs ence. Ask your distributor for a 6 pack dispenser. Try them on have developed an entirely new coupler circuit using three high your next six installations. If they aren't the finest you've ever frequency, ferrite core transformers in a unique "Balanced Bridge.' used. take them hack for a full refund. circuit. What does this do to performance? Well, for one thing, the 2 -set CC200 - For VHF and FM Specifications as above. Super Coupler provides an isolation figure of 22db minimum List $4.50 includes 5 -way mounting bracket and strap. across all channels (2 -13 and FM). Until now, the minimum isolation between sets with 2 -set couplers was about 10db or 3 times, CC400 - For VHF, UHF and FM (replaces LT -43). and was not constant on all channels. With the new Super Color Max. loss -6.23DB (A theoretical loss for perfect 4 way coupler Couplers, it's 12.8 times -four times better than the previous best. ± In fact. isolation is so good, you can put a dead short across one would be -6.0DB); Isolation 12DB min; Response 1/ %DB per set of output terminals without affecting the set connected to 6MC; VSWR: Input 1.15:1; Output 1.4:1 Max; Bandpass 20MC- other output. 1000MC; Impedance: Input 300ohm, Output 300ohm. List $5.50 LOSS is another key factor in measuring the performance of including 5 -way mount and strap. a coupler. The lowest possible theoretical loss in a 2 -set coupler is -3db but no coupler on the market had ever approached this Winegard's Famous CC23 Color Coupler ideal. Now, with Winegard's new 2 -set Super Coupler (CC200). the MAXIMUM loss is -3.2, nearly perfect and by far the best Finest VHF /FM color coupler on the on the market. market next to our new Super Color One more very important factor -IMPEDANCE. There are Couplers. List Price $3.95. two impedance matches to consider ... "Forward" from coupler to antenna. and "Backward" from set to coupler. A Winegard All New CVU -2 UHF -VHF perfect coupler would have a VSWR of Coupler Efficiently transfers UHF and 1.1: 1 on both matches. Some couplers VHF signals from antennas to sets. have good match one way but, until Serves as coupler or splitter for chan- now, no coupler ever had a good match nels 2 -83 (UHF -VHF). List $3.95. both ways. Winegard Super Couplers have a near perfect VSWR of 1.2:1 VHF /FM both forward and backward ... and on UHF all channels. This far exceeds other Splitter loss 3.5db 4.3db couplers on the market. Isolation 20 db 12 db VSWR 1.4:1 2:1

NEW COUPLER, Iineyarrd Co. PACK DISPENSER ANTENNA SYSTEMS 3003L Kirkwood, Burlington, Iowa CIRCLE NO. 237 ON READER SERVICE PAGE

www.americanradiohistory.com New trends in the development of service equipment point the way to a bright future for the technician.

SERVICE SHOP OF THE FUTURE

N YONE in Mac's Service Shop would have to be blindd sharper than we are accustomed to seeing. The pictures look and deaf not to suspect Christmas was coming. Every like those projected on a screen from color slides. In fact, the screen lighting up on the service bench seemed to dis- whole receiver looks exactly like a framed picture. Obviously play a ho -ho -hoing version of the jolly Old Elf or a commer- the sets are intended to hang on the wall. The picture tubes cial offering help with your Christmas shopping. From the are different from anything we know, for the frame around speakers of the radios and TV sets on the checkout bench them is only four or five inches deep." there came a muted blending of "Silver Bells," "White "Where's the chassis ?" Barney wanted to know. Christmas," and all the other hardy lyric perennials that "It's in a small compartment, about two inches by four bloom afresh this time of year. inches, in the bottom part of the frame," Mac answered. Matilda had, as Barney put it, "gone completely ape" in "Obviously it's a solid -state microminiature affair. And I decorating the front office. Wreaths of holly, sprigs of mistle- see no wires. Power is furnished by tiny long -life powerful toe, and candy canes ran riot over the walls and counter. A batteries far superior to anything we know now." large aluminum tree turned slowly on a rotating stand in "How about the instruments on the service bench ?" Barney one corner while its reflecting branches splintered the beam asked. "Are they any different ?" of a color -changing spotlight into hundreds of twinkling, "Much different. For example, the signal generator is a shifting pinpoints of brilliant color. crystal -synthesizing affair that can produce any desired fre- It even smelled like Christmas. Taking advantage of the quency from a few cps to many megacycles by simply having dwindling stream of customers as closing time approached, the proper buttons pushed. The accuracy of the output is Matilda was preparing some hot chocolate, and the sweet measured in cycles even at the highest frequency range. aroma drifted through the store. When she entered the serv- "Right next to it is a frequency meter of the type that ice department a little later carrying a tray with three cups actually counts the cycles electronically occurring in a pre- of the steaming confection and a great stack of vanilla cisely measured interval of time and then displays the result wafers on it, service work came to an abrupt halt. The office in cps with a digital readout. Readings are automatically girl perched on a stool, and Mac and Barney leaned against taken at very short intervals; so any drifting or moving back the service bench on either side of lier. All three surrendered and forth of the measured frequency is immediately apparent themselves completely to enjoyment of the collation, the as a change in the readout display. In this shop of the future rest, and the unspoken companionship. the working day is very short; so there's no place for time - Finally, after he had eaten at least half the vanilla wafers, wasting interpolating or guessing. The technician demands Barney sighed contentedly and put his empty cup back on the and gets quick and accurate information." tray. "Something about the Christmas season always makes "I suppose he still has to measure voltage, current, and me hungry," he confessed. resistance," Barney hazarded. "Do you see anything in the "Everything makes you hungry!" Matilda scoffed. "Now future that resembles our present v.o.m.'s or v.t.v.m.'s ?" Christmas always gives me a feeling of happy anticipation. "Yes, the technician uses a v.o.m. with an extremely rugged I have the tingly feeling something pleasant is just around but sensitive meter movement that has a built -in solid -state the corner. How does Christmas make you feel, Mac ?" amplifier. It is absolutely burnout- proof; yet its sensitivity "I guess it brings out the Janus in me," Mac answered. is such that it loads the circuit being tested much less than "Like the two -faced Roman god, I find myself looking back- does a modern v.t.v.m. This v.o.m. automatically selects the ward and trying to peer into the future. All afternoon I've proper range for displaying the voltage, current, or resistance been humming `Jingle Bells' and trying to imagine what being measured; and the proper scale is automatically illu- servicing is going to be like twenty or twenty -five years minated. A technician of the future would feel as `put upon' from now." if he were forced to use a present -day v.o.m. with a manual Barney wheeled around and pushed a little portable TV range selector as a modern gal taught to drive with an auto- chassis in front of Mac. He propped it up so the tube face matic transmission would feel if she had to go back to using was pointed toward the older man's face, and then snapped a clutch and a straight stick. out the room lights. Flickering reflections from the revolving "Now there's something interesting!" Mac exclaimed, cup- Christmas tree seemed to crawl about inside the darkened ping his hands on either side of the little picture tube. "The face of the picture tube. technician is connecting a tape recorder to the input ter- "Gaze deep into the crystal ball, O, Master, and tell us minals of the TV receiver. By golly, it's a video recorder! what you see," Barney intoned. Selected portions of the test tape provide a color -bar display, Going along with the gag, Mac waved his hands slowly a cross -hatch or dot design, a test pattern, and several other across the face of the picture tube and peered intently into signals useful in color -set adjustment that cannot be pro- its depths. "I see many bright colors, but everything is blurry duced by present -day generators. The test tape really pro- and out of focus," he said. "Ah, now it is becoming clearer. vides the technician with a standard signal, one that stays The color is coming from the screens of TV receivers on the precisely the same day after day. We know how useful such service bench. All of them are color sets, even the small a signal is to work with. portables; and the color is much brighter and clearer and "His scope connects through a coax lead to a fitting on 56 ELECTRONICS WORLD

www.americanradiohistory.com the chassis. Then a rotary switch con- using crystal -synthesizing signal gen- nects the scope's input terminals to vari- erators, counter -type frequency meters, ous portions of the printed circuitry. video tape recorders, and automatic This arrangement, in connection with v.o.m.'s. But instruments have a habit the signals provided by the test tape, of moving from the research laboratories enables him to determine very quickly into the service shops. That happened what portions of the circuit are operat- to the cathode -ray oscilloscope, the vac- ing normally and which ones are not. uum -tube voltmeter, the square -wave When a defect is found, that whole por- generator, the sweep generator, and tion of the circuit is unplugged and a many other instruments we now take new one installed." for granted." "How about me ?" Matilda asked. "Do "The idea of that computer sends I use any different equipment ?" me," Barney confessed. "Trying to keep "Yes indeedy!" Mac replied. "You will track of all the weaknesses of a zillion become much more than the office girl. different models of TV sets, radios, tape You will be the keeper of our entire recorders, hi -fi jobs, and record players service library. This library will be puts quite a strain on even my giant in- stored in a sort of computer about the tellect. It would be a great relief to size of a filing cabinet. Inside this, on know the little monster was remember- microfilm, will be stored complete serving everything for me." ice data on every piece of electronic "That was probably the most far- gear we expect to service. When we put fetched of all my imaginings," Mac said a `Super Silicon Six' receiver on the as he shrugged his way into his over- bench, you will punch a button or so coat, "but actually computers are going Features new Gen- Improved circuitry on this little monster and the diagram, ; ral Motors Delco uses reverse bias- to be doing a lot of `remembering' and transistors with pat- ing rectifiers, allows voltage data, and other pertinent infor- `evaluating' jobs in twenty years when ented "surface passi- operation beyond 230° vated ambientcontrol ". - solves heat problem. mation will be displayed on a large the cost of these units has been drasti- screen just above the service bench. cally Gives higher volt- Improved circuitry reduced. Computers will be doing v age ratios to 180 provides faster "Along with this basic information everything else; they may as well help Its, allowing higher transistor turn -off - ener voltage -Maxi- means less heat build- will be production changes, factory serv- us service TV receivers. Let's go, you mum output from coil. up inside transistors. ice notes, and hints and kinks applying two." U.S. Pat. 3089067 yr High -voltage spark to that particular model which you have on every transis- has up to 15 mil- gleaned from various tor proves beyond any liamperes output - sources and fed NEW NASA CENTER TO OPEN doubt that each one is nearly twice that of into the computer's memory. What's new and exclusive. electronic magnetoes. HE National Aeronautics and Space more, as soon as we have repaired the Administration's new Electronic Re- The NEW AEC 77A 50,000 -volt transistor ignition sys- Super Silicon Six, we'll give you the search Center in tem with GM Delco Type 2N2210A transistors guaran- Cambridge, Mass. was tees twice the output of any electronic magneto, at symptoms and the discovered cause of formally activated on September 1, 1964, half the cost. Guaranteed to outperform all other igni- the trouble and you will feed this in- when Dr. Winston E. Kock tion systems in existence, regardless of price. New took the oath performance carries with it greater power, new reli- formation into the computer. as director. ability, new dependability, new FIVE -YEAR GUARANTEE. "The computer will give proper The center is being established to pro- AEC 77A's constant high -voltage output guarantees more weight to all this information so that vide NASA with a greater electronics com- complete combustion . releases full engine power, increases gas mileage by 15 %, keeps plugs when we have another Super Silicon petence needed for the continued success and points clean beyond 50,000 miles, fires fouled of the plugs, makes engine run smoother, increases top Six to repair we'll simply give you the nation's space program. Working speeds, eliminates with industry 4 out of 5 tune -ups, gives you that symptoms and the model number. You and universities through- "tuned -up" performance for thousands upon thousands out the country, the center is of miles usage. will punch the proper buttons on the expected to advance a research program providing Every AEC 77A delivers full voltage at 2,000 rpm as monster, and it will promptly disgorge against 18,000 volts of other ignitions. AEC 77A con- improved electronic,. techniques and sys- tinues the various to deliver full voltage beyond 7 500 rpm, while causes of these symptoms in tems for space exploration. The center's other ignitions fail to deliver any voltage. At crank- the order of their likelihood! By con- will ing speed, AEC 77A delivers 20,000 volts as against efforts be in basic studies and re- 8,000 volts of other ignitions, guarantees instant start- stantly feeding the memory of the corn - search in the fields of instrumentation, ing in any type weather. puter with all this information, you vvill communications, data processing, navi- Completely waterproof and shockproof -every system make it more and more valuable to us. gation, guidance, and control. tested under actual operational load with 4 fouled and four operating spark plugs. Quality components in Like a meerschaum pipe, it will improve Design and construction of the center every AEC 77A, are supplied by General Motors (Delco is scheduled to begin in the latter transistors type 2N1358A), Motorola (zener diodes type with age." part of 1N28368), Prestolite (400:1 ignition coil), Mallory, "I don't know about all that," Matilda this year, with completion in four to five Sprague, IRC and others. years. Total personnel complement of said a little dubiously. "It sounds to me Installs easily in only 20 minutes by anyone. the center is expected to reach 2100 as though I'll be spending all my time by 1970. A feeding `the monster,' as you call it. I'll COMPLETE FACTORY WIRED SYSTEMS be working harder so you two can take AEC 77A with 400:1 coil, 6;'12 volt $39.95 it AEC 77A for Positive ground British easier." cars, 6/12 volt $39.95 Mac laughed and turned the shop AEC 77A 400:1 Coil only, 6 12 volt $11.95 lights back on. "I guess that's enough of Ballast resistor, var. .3 a seance for to .9 -250 watt $ 1.95 this evening," he said. "It's AEC K5 Complete do- it- yourself Kit, about time we closed up shop and went Negative ground only $32.95 home. Actually, as Barney knows, my soothsaying was little more than a pro- AUTOMOTIVE ELECTRONICS CO. g jection of modern trends in service 387 PARK AVE. SO., NEW YORK, N.Y. 10016 equipment. The instruments I men- NAME tioned have all been invented or are be- ADDRESS ing developed. You won't find many of CITY ZONE STATE AEC 77A them in the service shops, I grant you; - U For Negative ground 6/12 V $39.95 AEC 77AP For Positive `4ck sc;rs`°t ground 6/12 v $39.95 but that is chiefly a matter of cost. 4 - C -1 Kit $32.95 ID If r 400:1 Coil $11.95 ID Ballast $1.95 ' we could afford them, all of us would be "Unit Six ... Unit Six ... Where are you ?" `[l FREE BROCHURE ON AEC 77A SYSTEMS. EW -12; December, 1964 CIRCLE NO. 161 ON READER SERVICE PAGE 57

www.americanradiohistory.com RFOR "DOCTORS Where there's Substituting Transistors OF SERVICING" (Continnt-d frone page 41) a contact... The bias resistors ( Figs. 5D and 5E) are changed in value to accommodate the or a relay... larger base -to- emitter drop of silicon. Note that because the collector current is higher in this power circuit, a base -emitter voltage of 0.3 volt was used Service with Contact Shield! Pro- for the germanium circuit in calculating tective! Corrective! It not only the voltages and currents. cleans and safeguards contacts bet- These calculations are, of course. ap- ter on TV, radio, and hi -fi sets; on proximations and the higher leakage of all relay -operated electrical equip- the germanium transistor was taken into ment, regular protective mainte- account in the original resistance values. nance with this versatile cleaner Thus the probability is that the calcu- prevents sticky relays -while cor- lated bias resistor for the silicon replace- rective servicing unsticks them... ment is slightly ou the low side. Also, if cont in seconds. Promotes greater con- the transistor used has a higher gain than ductivity, keeps relays working the original design, a higher bias resist- smoother, longer. Contact Shield - ance is needed. If the gain is lower. a field, the professional service man's lower bias resistor is required. A sim- cleaner. ple check of voltage in any class. A circuit will determine if the quiescent cur- APPLICATIONS rent is being obtained. v INCLUDE: Fig. 6 indicates the voltage measure- Pin SpottersSp CLEANS, Alley Automatic ments which will show if the circuit is t_(if Bowling Pinball Machines and Vending Machines properly biased. Most class A amplifiers pF7o' Telephone Switchboards Slot Machines will be biased for a collector -to -emitter and other data IBM Computers voltage drop, V,E, of a couple of volts to equipment processing relays, such as 10 volts. A small -signal circuit will be For handy guidebook to better servicing, Equipment using Industrial etc. at the lower end of this range and a write Channel Master Corp., Ellenville, N.Y. welding machines, large -signal circuit at the higher end. It is easy to estimate the proper value by taking the sum of the resistance drops in SUB CARRIER DETECTOR the collector and emitter circuits using for the reception of the desired value of emitter current. and background music programs (continuous music without commercials) now being transmitted as hidden subtracting from the supply voltage, programs on the FM broadcast band from coast to as follows: coast. Use with any FM tuner. Detector plugs into Vrc, existing multiplex output of tuner or easily wired into discriminator. VcE=Vrr- (Va rnitrrtnr+Vr ,nlirl, r) kits with pre -tuned coils, no alignment necessary $45.00 self powered detectors $75.00 Complete crystal controlled suh- carrier receivers with Measure the voltage WE in the circuit usable sensitivity of 1 micro volt kit $169.00, wired by placing a voltmeter across the tran- unit $219.00. sistor's collector and emitter. If it is NEED A MUSIC ASSOCIATED Sound Systems since 1950 higher than the estimated value, then 1 10 VOLT 65 Glenwood Road, you do not have enough transistor base Upper Montclair, New Jersey A.C. OUTLET? phone 744 -3387, area code 201 current, so lower the value of R1 slightly. This is easily done by shunting In CAR, BOAT or TRUCK, RI with another resistor of large value, YOU HAVE IT WITH A say, I megohm. If the voltage measures when it's time to think of college too low, it means that there is too much base current, so raise the value of R1. POWER you should read this In practically all cases, the voltage FREE CAREER BOOKLET rating of the equivalent silicon transistor INVERTER will be higher than the ger- about electronics at substitute Actually gives you 110 volt, 60 manium type, so there is no cause of con- cycle A.C. from your 6 to 12 volt cern in the matter of breakdown. D.C. battery! Plug inverter into For additional details, see "Selecting cigarette lighter, and operate High -Frequency Transistors" in the Sep- lights, electric shavers, record tember, 1964 issue. players, electric tools, portable TV, MILWAUKEE Ms220 radios, testing equipment, etc. SCHOOL OF ENGINEERING Fig. 6. Measurement of VCE can Frequency stable within one cycle. Dept. EW -1264, 1025 N. Milwaukee Street be used to check bias current. Milwaukee, Wisconsin 53201 Models from 15 to 600 $12 95 Tell me about an engineering career through watts, priced as low as LIST residence study in: L] Electrical fields Mechanical fields See Your Eledr one. Ports Denier or Jccb _r, or Write: INFUT Name Age CORPORATION 1058 Raymond Ave. Address Paul 8, Minn. St. City, State In Canada, Atlas Radio Corp. Ltd. - Toronto, Ont. L J CIRCLE NO. 228 ON READER SERVICE PAGE 58 ELECTRONICS WORLD

www.americanradiohistory.com Which Stereo Receiver Is Your Best Value'? BRAND IHF POWER TUNER CIRCUIT PRICE A 70 Watts AM -FM Transistor $369.95 FM Stereo AM -FM B 80 Watts FM Stereo Tubes $374.50 C 100 Watts AM -FM Transistor $619.95 FM Stereo 0 70 Watts FM Stereo Tubes $429.90

E 66 Watts AM -FM Transistor $195.00 FM Stereo

F 60 Watts FM Stereo Tubes $354.45 G 60 Watts AM -FM $273.90 FM Stereo Tubes H 100 Watts AM -FM Transistor $579.90 FM Stereo

I 70 Watts AM -FM Tubes $269.95 FM Stereo IF YOU CHOOSE E GO DIRECT TO THE COUPON & COLLECT $75 TO $425 SAVINGS!

I es 1 . "E" is the Heathkit AR -13A All- Transistor, simultaneous adjustment of volume, bass, V.C; thIn (1-, '0 Intermodulation distortion: G,t ! g n a t mi. _d 4.1. All -Mode Stereo Receiver. It's the first all - and treble of both channels; 3 stereo in- Hum & noise::. - - .r ,,Isd output, Au, transistor stereo receiver kit. It costs from puts; and a separate control for balancing t. Channel separation: -0 o. Input s en sitivity: Outputs: 4, 8, E 16 $75 to $425 less than the finest stereo receiv- both channels. The AM tuner features a uts. Controls: 5- ers on the market today. This alone makes high -gain RF stage and a high Q rod Opal Tandem Volumr: Cori, I; Phase Switch: Ioc.t the AR -13 unique. But dollar savings are antenna. The FM tuner has a built -in line J IGFF Sv.ltch. FM: Tuning only one reason why it's your best value. cord antenna plus external. antenna con- range: -.:, to 108 mc. IF frequency: 10.7 roc. Frequency response: _ 4 b, 20 to 15,000 cps. Capture ratio: 10 nectors. Antenna: GO cud (lob: rnal for local reception;. Even if you can afford to buy the costliest quieting sensitivity: uv 'or 30 db of cup tlnq. Image rejection: -:0 v. IF rejection: 70 M. Harmonic distortion: In addition, there's a local- distance switch model, you can't buy better performance. I . STEREO MULTIPLEX: Channel separation:

- . 19 KC& 38 KC Start with the AR -I3A's 43- transistor, 18- to prevent overloading in strong signal suppress sio : SCA rejection: 35 db dawn from areas; a - diode circuit. It's your assurance of cool, squelch control; AFC for drift outout. AM: Tuning range: 'h to 1620 ko. IF frequency: 4_5 instant, "hum- free" operation; long, free reception; plus flywheel tuning, tuning Lc. Sensitivity: . 4:.., c. 9 us 55 1000 kc. Image re- meter, and jection: 40 db. IF rejection: 55 1b C 1000 cps. Harmonic trouble -free life; and the quick, clean, un- lighted AM & FM slide -rule distortion: Less thin n 1000 ua input, 400 cps ,11 modified response of "transistor dials for fast, easy station selection. The 30% modulation. Hum and noise: 40 db. Overall dimen sound" lions: 17' L x 5%' H n 14%' D. ... characteristics unobtainable in tube secondary controls are concealed under types. the hinged lower front gold aluminum FREE CATALOG panel to prevent accidental system setting Send for your Free copy to- changes. Both of the AM and FM "front - day! Fully describes over 250 Next, there's wide -band AM, FM, FM exciting Heathkits at savings Stereo tuning for distortion -free reception ends" and the AM -FM 1.F. strip are pre - of 50% or more! Choose from to delight the most critical ear. It has two assembled and prealigned to simplify the world's largest selection preamps. construction. of quality instruments in easy - And its two power amplifiers to- assemble kit form! provide 66 watts of 1HF Music Power, 40 watts of continuous sine -wave power. And Compare its impressive specifications. it's all housed inside one luxurious, com- Then go direct to the coupon, and order the AR -13A. Now sit back and relax . . . HEATH COMPANY, Dept. 15-12 -1 pact walnut cabinet . . . just add two you've saved Benton Harbor, Mich. 49023 speakers for a complete stereo system. just $75 to $425 without compromising! Enclosed is $195.00 plus freight. Please send Model AR -13A Stereo Receiver. There are plenty of operating conveniences, Kit AR -13A, 34 lbs. $195.00 Please send Free Heathkit Catalog. too. Like automatic switching to stereo; Name automatic stereo indicator; filtered tape SPECIFICATIONS -AMPLIFIER: Power output per channel (Heath Rating): 20 watts /8 ohm load. (IHFM Music Address recorder outputs for direct "beat- free" Power Output): 33 watts /8 ohm load. Power response: ±1 db City State Zip fions 15 cps to 30 kc g rated output. Harmonic distortion: stereo recording; dual- tandem controls for HF -173 (at 1 paled output) Less than %@ 20 cps: less than 0.3% @ 1 I December, 1964 CIRCLE NO. 187 ON READER SERVICE PAGE 59

www.americanradiohistory.com /00 CVT HOLES L.ADIC )

TA8T TV NEWS

NORMIALLY, one thinks of earth sat- goes up, the transducer becomes thin- ellites as a means of relaying infor- ner. A point is soon reached where the mation between continent- spaced transducer crystal cannot deliver any ground stations. However, there are power without shattering. At this point, some mundane things, of a non -elec- the crystal is so thin that it becomes tronic nature, being done with these very difficult to handle without frag- man-made space objects. menting. According to reports from France. To replace these brittle crystals, simultaneous photographs of Echo I Westinghouse scientists have success- GREENLEE CHASSIS PUNCHES taken both in France and Algeria :tre fully "grossli ultra -thin films of crys- Alike accurate, finished holes in 11 t enabling the French to accurately lo- talline cadmium sulphide, built up atom minutes or less in metal, hard rubber and plastics. Nu tedious sawing or cate future satellite telemetry and track- by atom in an orderly. near- perfect fash- filing -a few turns of the wrench ing stations being built across Europe ion. The films, only 10 to 100 millionths does the job. All standard sizes . . and Africa by the European Space Re- of an inch thick, are grown inside a round. square. key, or "D" shapes for search Organization ( ESRO ) . Echo I, vacuum chamber. They are deposited Sockets. switches. mters. etc. At your electronic parts dealer. Literature on probably seen by more people than ans' from hot vapors in such a way that request. other man -made space object, is losing the required numbers of the two kinds GNEQ/II ig the smooth shape that permitted reflec- of atoms in the compound cadmium GREENLEE TOOL CO. 2027 Columbia Ave., Rockford, Illinois tion of radio waves, but is still brilliant sulphide stack themselves up in perfect CIRCLE NO. 184 ON READER SERVICE PAGE enough in the night sky to serve trian- order to form what is felt to be a nearly gulation purposes. continuous single crystal without gaps. Get Your First Class Commercial At the 15th International Astronauti- These thin -film ultrasonic transducers cal Congress recently held in Warsaw, are used in the study of certain basic Poland, a technical paper 'as presented materials. They are plated on the sur- F.C.C. LICENSE to show that any satellite emitting a face of the material under study and known frequency radio carrier can be excited. The lifetime of the sound waves auir/ar! used as an accurate triangulation tool. and the velocity with which they travel Here, use is made of the Doppler yield basic data on the physical struc- Career opportunities in communi- shift principle. if a radio receiver is ture of the material being studied. cations electronics are almost located at a known position and a mo- unlimited. Prepare now. Let bile receiver placed at some remote spot. Improved Ultrasonic Testing Grantham train you - by corre- the difference in instantaneous Doppler Speaking of ultrasonics. readers using spondence, or by classroom and be used to ac- tool to determine Haws in solid instruction. Get your shift at both stations can this laboratory two. It be- will be interested to know first class commercial F.C.C. license curately triangulate these structures in as little as 3 months, or at a comes possible to mount the receiver that a new approach to ultrasonic test- slower pace if you prefer. Then, in a vehicle and pinpoint as many as five ing has been made by the Watervliet continue in more -advanced elec- hi six locations a day. .Arsenal of the U.S. Army. tronics training if you wish. Di- Depending on the amount of equip- The chief difference between this new ploma awarded. Our catalog gives ment employed :ntd the type of ter - approach and former techniques is that full details. r.iin involved. an entire country could this new method nscs separate transmit- Learn how our training can pre- be accurately mapped at low cost. ter and receiver transducers that permit pare you for your F.C.C. license; "through" transmission rather than the write or telephone the School at any principle. one of the teaching divisions listed Ultra -Ultrasonic commonly used reflection below, and ask for "Catalog 46." \lost of us think of ultrasonics as This more exacting "shadow" method sound waves solnek hat higher in fre- has proved more accurate than pulse Grantham School of Electronics quency than human hearing. usually echo observations and can record a flaw 3 in depth. The new 1505 N. Western Av., Los Angeles, Cal. 90027 being somewhere in the neighborhood as small as /16 -in. iPhone: HO 9 -78781 of several tens of kilocycles. method is not affected by surface rough- Scientists at 1I'rstillghol:se Research ness, angle of and Haw orientation, or 408 Marion Street, Seattle, Wash. 98104 Labs. recently disclosed a technique other variables that are detrimental to (Phone: AMA 2 -7227) whereby it now becomes possible to gen- the reflection system. 3123 Gillham Road, Kansas City, Mo. 64109 erate ultrasonic sound waves up to fre- The new approach is used for testing (Phone: JE I-63201 quencies approximating 9000 mc. with cannon barrels where both transducers one of the barrel to 818 -18th St., NW. Washington, D.C. 20006 the possibility that even higher fre- are drawn from end (Phone: 298-740) quencies may be generated in the future. the other. Readout is on a cylindrical Usually, as the ultrasonic frequency recorder.

60 ELECTRONICS WORLD

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Exclusive I leach Icatures For t nequalled Per- circuitry that money can buy . . at up to The Only Color TV You formance! That's right. No matter hors inan 5;200 savings. You enjoy rock -steady pictures Can Install 3 Ways! of your hard -earned dollars you pay for w ith no overlap or color fringing. another brand of color TV, none 1. In New Heathkit Deluxe Walnut Cabinet (Illust. can equal above), the performance of the Heathkit All- Channel. But Don't Take Our llurd For It! model GRA -53 -7, 85 lbs $115.00 2. In Heathkit walnut- finished hardboard cabinet High Fidelity 21" Color TV! WTI) ! .I // color See the special articles on the Heathkit GR- Illust. below). model sets require minor periodic adjustments to 53A in the May issue of Popular GRA -53 -6, 52 lbs....$49.00 Electronics, 3. In a wall, bookshelf. maintain peak picture performance. The June issue of Raclin -TV Experimenter. Febru- or custom cabinet! Heathkit GR -53A is the on/I set with a ary issue of Popular ,ilecluiflics, April issue "built -in service center" that provides the of Science & .Mechanics. and the August issue facilities for perfect picture adjustments. of Radio -Electronics! Heath's simple -to- follow instructions & de- Now Compare The Features tailed color photos show ou exactly w hat and The to Price! look for and hose to achieve it ... quickly. easily! You become the expert! Result ! Beau- In addition to the ones already mentioned, tiful, true -to -life color pictures cla in and there's the high definition 70` 21" color tube day out ... and nn costly color TV service with anti -glare bonded safety glass; 24.000 calls for simple picture alignment! volt regulated picture power; 27 tube, 8 diode circuit; deluxe And since you service & maintain the Standard- Kollsman VHF set tuner with push yourself, a costly service -lo -tune fine tuning for indi- contract isn't re- vidual channels quired! Heath warrants the picture tube for and transistorized UHF tuner for all -channel (2 -83) I year, all other parts for 90 days. reception; automatic color control and gated AGC for peak No Trade -In Required! performance; line thermistor for longer tube life: tsso hi -li Keep your present set as a outputs plus tone control: trans- braids -second" former set for the den, bedroom. children's room. etc. operation: chassis & tube mounting on sturds one -piece metal support for easy HEATH COMPANY, Dept. 15 -12 -2 Benton Harbor, Quick & Easy To Assemble! set -up and servicing; Plus a low price of only Michigan 49023 Enclosed is $ No special skills or knowledge required. All S399. , plus shipping. critical assemblies are Please factor-built and test- Use The send Model(s) ed. Simple step -by -step instructions take Coupon & Order Yours Now! ou ] Please send FREE 1965 Heathkit Catalog. from parts to picture in just 25 hours! Ancl be sure to check the appropriate box to get your Free new 1965 Heathkit Catalog Convenient Nome Time-Pay Ilan! with complete descriptions & specifications (Please Print) Only 10 dow n, and the rest in Cass monthly of the GR -53A as well as over 250 easy -to- installments. Get free catalog for (Ulf details. build kits! Address Finest Components, Nlost- Advanced Kit GR -53A, chassis, tubes, mask, Circuitry UHF & City State Zip With the Heathkit GR -53A s ou-re assured of VHF turners, nrornrtin,i kit, and special CL -193 the finest parts Prices 8. specifications subject to change and most advanced color TV 6" .v 9" speaker, 127 lbs 5399.00 without notice. December, 1964 CIRCLE NO. 187 ON READER SERVICE PAGE 61

www.americanradiohistory.com where space is small with calibration and reliability Receiver Frequency Control accuracy of 200 cps. (Continued from page 54) To clarify its operation, here is an essential... example of how it works. Suppose it is desired to tune across that part of the spectrum and to use crystal -controlled class -D Citizens Band from 27 to 27.255 converters to widen coverage. Unlike mc. the digital approach, this technique al- The first step would be to set the lows continuous tuning -but like straight "Megacycles" dial on the RA17 to "27 ", crystal control, becomes prohibitive which would tune the variable oscillator when exceptionally wide spectrum cov- to approximately 67.5 mc. In the first erage is desired. Typical commercial mixer the incoming signals between 27 applications of this technique include and 27.255 mc, would mix with the Collins' "51 -" series of receivers, using 67.5 mc. to produce output frequen- up to 30 crystals to provide coverage cies from 40.245 to 40.5 mc. The sec- S W ITCH CRAFT from 0.5 to 30.5 megacycles. ond mixer would mix the 67.5 -mc. v.f.o. BUTTON SWITCHES By a judicious mixture of this ap- signal with the 30th harmonic of the proach and the frequency synthesizer 1 -mc. crystal to produce a 37.5 -mc. out- Unusually small completely metal enclosed pushbutton switches are not technique, British engineers have put put for the filter. much bigger than a I/2" threaded bush- into production a receiver which per- The 40 -mc. range signals would be ing -yet they feature a wide variety of forms in the same manner but employs amplified in the first i.f. circuits coupled with smooth, non- stick- strip, then ing action. Non -locking, red or black only a single crystal for all transfer ref- mixed with the 37.5 -mc. filter output buttons. Behind panel mounting (left), or erences. to produce signals in the range 2.745 to front -of -panel mounting (right). Which A one is right for you? block diagram of this receiver, the 3 mc., which would be passed on to the Model RA17 from Racal Engineering final tunable receiver. oA Single "Make" Ltd., Bracknell, Berks, England, is shown Should the v.f.o.'s frequency drift up Single "Break" in Fig. 7. The basic operation is similar to 67.6 mc., the first i.f. signal- frequency Single "Break- Make" to the spectrum -generator approach di- range would move to 40.345 to 40.6, 4ßóA agrammed in Fig. 4, but using different but at the same time 6 "Make Before Break" the output of the frequencies and circuit constants. 37.5 -mc. filter would move up to 37.6 11 Write for Catalog S -301 In the RA17, the incoming r.f. signal mc. When the third -mixer action was in the range from 3 to 30 mc. is first complete, output frequency range would mixed with the output of a variable still be 2.745 to 3 mc. Thus accuracy 5577 Elston Ave., Chicago, Illinois 60630 oscillator which covers the range 40.5 of setting the v.f.o. is not essential. Canada: Atlas Radio Corp., Ltd., 50 Wingold Ave., Toronto, Ontario to 69.5 mc. Stability of this oscillator Since the signal is inverted in the CIRCLE NO. 224 ON READER SERVICE PAGE is of no particular importance, as long first mixer and is never re- inverted, the as it remains within 150 kc. of its orig- final receiver tunes "backward ", i.e., RADIOTELEPHONE inal setting. Output of this first mixer 3 mc. is the low end of the signal band becomes a 40 -mc. inverted signal, which and 2 mc. marks the high end. Since LICENSE is applied to an i.f. amplifier having a this is true on all frequency ranges, the passband 1300 kc, wide. dial is merely calibrated in reverse and The variable oscillator output is, at final operation is not affected in the MANUAL the same time, mixed with the harmonics least. of a high- precision 1 -mc. crystal oscil- In addition to the techniques de- lator to produce a variable- frequency scribed here, several other less unusual $5.75 output spectrum ranging up to nearly approaches have been taken. For cov- (foreign $6.25) 40 mc. Output of this second mixer erage of restricted portions of the spec- Book :,030 passes through a 37.5 -mc. filter having trum, such as for some types of a bandwidth of ± 150 kc. Thus the fre- commercial communications, aircraft, quency of the single signal present at and amateur use, designers have em- the output of this filter lies between ployed conventional circuits and tech- - helps you prepare for all U.S.A. 37.35 and 37.65 mc. niques but have improved accuracy and commercial operator's license exams The signal slice appearing at the out- stability by using construction methods Here are complete studyguide questions and answers in a put of the 40 -mc. i.f. amplifier is then previously reserved for transmitter fre- single volume. Helps you understand every subject needed to obtain an operator's license. mixed with this 37.5 -mc. signal from quency control. the filter to produce an output covering An understanding of these new tech- RADIO HANDBOOK - largest comprehensive reference source on radio ever published. More "How -to- build" data the range 2 to 3 mc. This 2- to 3 -mc. niques will go a long way toward pro- than any book in the field. Gives simplified theory . latest design data. Book =166 $9.50 (foreign, $10.50) spectrum then goes to a conventional viding knowledge of what makes a mod- receiver, covering only this limited range ern communications system operate. The leading book on Transistor Communications Equipment. 27 TO 40.500 TO 3 TO TRANSISTOR RADIO HANDBOOK by Donald L. Stoner, 27.2BSSMC. 40245MC.\ 2.745MC. W6TNS, and Lester A. Earnshaw, ZL1AAX. Simplified circuit theory, plus practical construction projects. FIRST I.F. 2-3MC. RC V R. R.F. F.. 0 -50 MC. Y FIRST THIRD Book =044 $5.00 --m - 39.35 TO +imo CALIBRATED TO (foreign, $5.50) AMPLIFIER FILTER MIXER 40.65MC. MIXER 200-CPS ACCURACY SURPLUS RADIO CONVERSION MANUALS - practical con- 67.DMC versions of popular surplus equipment. Send stamped envelope for full data. VFO ORDER FROM YOUR FAVORITE ELECTRONIC PARTS DISTRIBUTOR. 40.5 -69. S MC. ("MC:' ADJUSTMENT) 37 .5MC. If be cannot supply. send us his name and remittance, und we will sulply. 67.5M0. EDITORS and ENGINEERS, Ltd. 29,30,3IMC. IMC. 37.5 MC. Summerland 2, California 93067 HARMONIC SECOND XTAL FILTER Fig. 7. Diagram of Dealers. Electronic distributors, order from us. Bookstores, GENERATOR MIXER libraries, newsdealers, order from Baker & Taylor Co., OSC. 137.35- 37.65MC.1 British receiver using Hillside, N.J. or Momence, Ill. Export (except Canada), order only single crystal. from H. M. Snyder Co., 440 Park Ave, South, New York 10016. 3e.5, 37.5,136.5MC. CIRCLE NO. 177 ON READER SERVICE PAGE 62 ELECTRONICS WORLD

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New Heathkif Deluxe Transistor Stereo! Luxurious New Walnut Cabinet Styling! sired station for rock -steady, drift -free reception Please Your Ear, Your Eye Do you consider appearance as carefully as per- ... automatic gain control that eliminates "blast- & Your Sense Of Value! formance when choosing stereo components? ing" or "fading" of incoming signals, keeps Choose this matched Heathkit Transistor Stereo If you do, then you'll delight in the new look volume constant ... adjustable FM squelch to pair now for better performance and appearance of Heathkit Deluxe Transistor Stereo! Sleek, let you tune across the dial without annoying at lower cost! richly warm walnut cabinets. Clean, uncluttered between- station noise ... stereo phase control Kit AJ -43C, tuner, /9 lbs. $119.95 charcoal gray upper front panels. Soft, refracted for maximum separation, minimum distortion Kit A.1 -2 /C, amplifier, 29 lbs. 5149.95 panel lighting. Hinged, lower front walnut panels ... and a factory -built & aligned FM "front - to neatly conceal all secondary controls and end" tuner and 5 -stage FM I.F. circuit board avoid accidental system setting changes. Beauti- for quick, easy assembly! FREE 1965 ful enough to capture the spotlight in any room! Matching Heathkit AA -2t Stereo Amplifier! HEATHKIT CATALOG Se these and over 250 other exciting And The Sound? This superb unit boasts a 26 transistor, 10 diode Heathkits available in easy -to -build As modern and beautiful as the new styling. circuit that produces 70 watts continuous, 100 kit form. Save 50% or more by doing Transistor sound with its broad, clean, unmodi- watts IHF music power at ± I db from 13 to the easy assembly yourself! Send for .0,, free catalog today! fied response . no compromising! Add cool, 25,000 cps. And you enjoy complete freedom instant operation, simplicity of assembly and from microphonics, effortless transient response, L J the low Heath prices ... and you have the best and cool instant operation ... characteristics value in transistor stereo today - bar none! unobtainable in tube- types. Under These Beautiful Cabinets ... In addition, there are complete controls, plus all HEATH COMPANY, Dept. 15 -12 -3 inputs and outputs to handle any program source Benton Harbor, Michigan 49023 you'll find the most advanced solid -statu cir- In Canada: Daystrom, Ltd., Cooksville, Ontario cuitry. The magnificient Heathkit AJ -43 Stereo & most speaker impedances. Circuit safety is Enclosed is $ , plus shipping. assured with 5 fast -acting, bi -metal circuit break- Tuner features 25 transistors and 9 diodes ... ers ... no fuses to replace ever! Transformerless Please send Kit wide -band AM, FM & FM Stereo to satisfy any Please send FREE 1965 Heathkit Catalog. listening wish ... automatic switching to stereo output circuit and multiple feedback loops pro- plus an automatic stereo indicator light that vide fine fidelity and low distortion levels. Name (Please Print) signals when stereo is received filtered left & With its encapsulated, epoxy- covered circuit ... Address right channel outputs for direct, beat -free stereo modules and five stable circuit boards, the recording ... separate AM & FM tuning meters AA -21's assembly is fast, simple and fun ... City State Zip_ ... automatic frequency control to lock in de- requires no special skills or knowledge! Prices 8 st ec l c.,ticns sub.ect to change without noiic HF -177

CIRCLE NO. 187 ON December, 1964 READER SERVICE PAGE 63

www.americanradiohistory.com the stereo portion of FM multiplex receivers. The MX129 generates a composite t1Jl81ll-'lll 11 TEST multiplex signal the same as that nor- (ir OWarii i mally transmitted from an FM station U NM during a stereo program. It consists of EQUIPMENT 161111111111111 I right- and left -channel information prop- PRODUCT REPORT erly combined, a crystal -controlled 19 -kc. pilot and, when desired, a 67 -kc. SCA signal. The composite signal is available from a front-panel jack and also modulates an FM oscillator for injection into the antenna terminals of a Mercury Model 1400 In- Circuit Capacitor Tester receiver. For copy of manufacturer's brochure, circle No. 62 on coupon (page 15). In addition, the unit contains a monitoring voltmeter which is calibrated in peak -to -peak volts and decibels. A jack marked "Ext. Meter" is provided for connecting the meter to stereo speakers or at other points after detection; thus no other equipment is required for checking channel separation or alignment. Full control of left- and right -channel signal selection and signal level is offered by separate signal and level controls for each channel. Each channel can be fed with a choice of two internally generated signals, 60 cps or 1000 cps, or can be fed with an external signal. jacks are provided on the front panel for the external signals. The signal level of each channel in peak -to -peak volts can be monitored on the panel meter. (See diagram.) The 19 -kc. pilot carrier, which is added to the composite signal, is adjustable and its level control is calibrated from zero to 10 percent of modulation. THE Mercury ModelM 1400 is a valu- signal reaches the detector in the tester The pilot can be generated separately for able service aid for in- circuit testing and the eve indicator tube is kept open. 19 -kc. amplifier peaking in a receiver by of all types of capacitors, from the small- This holds true even when there is a merely turning the left - and right -level est ceramic types to large electrolytics. shunt path of very low resistance. controls to zero. The tester will check for open or shorted For the opens test, the capacitor is A 67 -kc. SCA signal is available at the capacitors without the necessity of replaced at the end of a tuned line con- SCA jack and also modulates the r.f. car- moving them from the circuit. Capaci- nected to the tester's 20 -mc. oscillator. rier. This signal is required for 67 -kc. tance values are measured in- circuit for As long as the capacitor under test is trap adjustment in new stereo receivers. all popular electrolytic capacitors. not open, the oscillator continues to run A separate switch selects either the SCA An important feature of the electro- and the eye is held open. A leaky or signal or the 1000 -cps internal signal. lytic test is that the low test voltage shorted capacitor kills the oscillator and The panel meter selector switch has employed protects low -voltage electro- closes the eye indicator tube. five positions: left level, right level, com- lytics used in transistor radios. Many of In order to check electrolytics, the posite level, 3 volts peak -to -peak exter- these are rated as low as 3 volts d.c., same 2.9 -volt test signal mentioned nal, and 30 volts peak -to -peak external. and the Model 1400 is able to test these above is used except that now the iso- The external -volts scale of the meter is safely with no chance of damage. lating resistor is a front -panel calibrated also calibrated in db. The indicator tube used is a new potentiometer. The pot is rotated until The r.f. output is factory -tuned to 100 EM84 type with a bar -shaped fluores- the eye just closes. The scale pointer LEFT RIGHT EXT. EXT. 60 CPS cent screen. Directly above the tube then indicates the value of the electro- SIG. SIG. there are printed instructions describing lytic over a range of about 2 to 450 µf. its pattern for various capacitor defects. The power supply for the tester is

for safety. The I -KC. INT. In testing a capacitor for shorts, a line -isolated unit em- LEFT RIGHT OR SIGNAL 2.9 -volt, 60 -cps signal is applied to it ploys an all -metal case with convenient SIGNAL 67 -KC. SCA through an isolating resistor. The capaci- carrying handle and storage compart- COMP?OUT tor under test forms a simple voltage ment for power and test leads. The divider with the resistor. If the capacitor Model 1400 is available at a price of LEFT COMP. RIGHT LEVEL LEVEL LEVEL is not shorted, then enough of the test $29.50.

Sencore MX129 FM- Stereo Multiplex Generator I9 -KC. METER R.F. PILOT SELECTOR MOD. For copy of manufacturer's brochure, circle No. 63 on coupon (page 15). LEVEL THE Sencore Mí129 is a crystal -con- manufacturer, service technician, or ex- R.F OUT trolled, transistorized FM multiplex perimenter with all signals required for EXT. METER METER generator and analyzer. It provides a analyzing, troubleshooting, and aligning 64 ELECTRONICS WORLD

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No Extras To Buy .. . Saves Hundreds of Dollars New Heathkit%Thomas "Coronado" Transistor Organ!

Every Organ Feature You've Ever Dreamed special rhythm effects. Pedal Volume Control. It's Truly A Professional Organist's Dream Of! ,lust look what you can create on this f'ihrato Switch ... for ssarmth & beauty. \Vith A Beginner's Simplicity! And yet you beautiful instrument! 17 True Organ Voices Evpres.siort Pedal ... to adjust volume from don't have to he an electronics wizard to Diapason ... 16' & 8', Bass Clarinet 16', softest sshisper to full majesty. Reverb ... build it, nor a professional organist to play Trumpet 16', English Horn 8', Violin 8', Oboe to add concert -hall realism. Treb /e Accent it. Famous Heath -"Engi -nuity" has reduced 8'. Bourdon 16', Flute 8', Flute D'Amour 4', Tab ... adds new clarity & brightness to solo assembly to simple steps that require no Quint 5 -1/3', Saxophone 8', French Horn 8', work. Headphone Outlet ... play any lime special talents, tools or knowledge. And the Cello 8', and Chimes - all at the simple without disturbing others..411- Tran.ci.uor 75- famous Thomas "Musical Fun Book" is touch of a tab! 2 Separate Speaker Systems Wart EIA Peak : \iresic Power Amplifier. Pre- included to start you playing many favor- a built -in 2 -speed rotating ... Leslie plus Tuned Tone Generator ... to help you easily ites fast ! A special, recorded 48- lesson two -12" Main speakers. With the Leslie sys- tune the organ, no special "musical" ear course is also available that lets you learn tem you create the beauty of full "theatre" needed! Transistor Tone Generator Boards at your liesure! Regular S50 value ... only organ, or a randomness of sound adaptable ... warranted for 5 years! Luxurious Hard- S19.95! for religious music. And by playing through wood Cabinets & Bench handcrafted with Pay As You Play! Only 5125 dn., as little both systems at once, you produce an ex- walnut finish! as S27 a month. Get free catalog for full citing "stereo" effect. 28 .Votes Of Chimes No Extras, Nothing More To Buy! Everything details - now! . .. worth $500 to S20{)0 as an "extra" on you need for Kit GD -983, organ & matching bench, other organs. Creates hundreds of chime vari- complete playing versatility is included. There are no speakers, amplifiers 290 lbs... .S125 dn.. as /on as 527 nto... . ations. Color -Tone Attack, Repeat & Sustain or other "hidden necessities" to add as 5849.00 Percussion[ ... the only organ to give you with r other organ kits. It's all there at one price all 3 to create an infinite number of beautiful ... even the bench! HEAR IT YOURSELF! musical effects. You can vary the rate of Convince yourself by sending for a 7 ", repeat percussion & you can select short or Saves I lundreds Of Dollars! Save more than 331/2 demonstration record! Order medium Sustain. 2 No. GDA -983 -2 for Deluxe GD -983 Full 44 -Note Keyboards. 5400 over the factory assembled version. And organ, GDA -232 -5 for low -cost Manual Ba/auce ... to adjust relative volume you could pay as much as $1000 more GD -232A organ. Each record 50c. for Do it now! & to accentuate either manual. /3 Note Heel other brands and still not enjoy as many & Toe Pcdalbnarcl. Pedal Srrsrai,, ... for features! ` -- FIl®AT>EISZ - - J

it HEATH COMPANY, Dept.15 -12 -4 Benson Harbor,'... ch ;gan 49023 10 true organ voices Variable Repeat In Canada: Dc,,'ron,, Ltd., Cooksville, Ontario Percussion for additional effects Two Enclosed is S _. Please send model Please send Free 1965 Healhkit Catalog. 37 -note keyboards 13 -note heel World's Lowest Cost & toe bass pedals 20 peak power -watt ampli- Name 2 Manual Organ fier Walnut cabinet Transistorized ¡Please Print) Heathkit /Thomas plug -in tone generators ... warranted for Address five full years Expression pedal. "Largo" City Stete Zip K i I GD -232A, organ only, 158 lbs. Paces 0. rcecf,cotions subject to change w.'heut $349.95 notice. CL197 December, 1964 CIRCLE NO. 187 ON READER SERVICE PAGE 65

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Fill in coupon for a FREE One Year Sub- scription to OLSON ELECTRONICS' Fantas- tic Value Packed Catalog - Unheard of LOW, LOW PRICES on Brand Name Speakers, Changers, Tubes, Tools, Stereo Amps, Tuners, CB, Hi -Fi's, and thousands of other Electronic Values. Credit plan mc., but can be adjusted by a tuning tool anced, a channel- separation measure- available. through the front panel from 90 to 105 ment should be made. With the mono NAME mc. If interference is experienced from a signal still applied, turn the 19 -kc. pilot ADDRESS local station, the r.f. may be adjusted to signal up to 10% modulation. Measure CITY ZONE STATE a clear spot on the band. the level in decibels at the left speaker, If you have a friend interested in electronics In troubleshooting a stereo receiver, then switch off the left channel in the send his name and address for a FREE sub- the following three steps will generally MX129. The tone should come from the scription also. pinpoint the defective circuit: right speaker only. If there is a tone from the from speaker, measure its level OLSON ELECTRONICS, INC. 1. Feed the r.f. output the left MX129, modulated with a 1000 -cps on the meter. Subtract this reading from 328 S. Forge Street Akron, Ohio 44308 mono signal, into the antenna terminals the first for the exact amount of separa- of the receiver and balance the outputs tion in the receiver. If the amount of CIRCLE NO. 203 ON READER SERVICE PAGE to the speakers using the external meter. separation is inadequate, the adapter (A mono signal is produced by selecting portion of the receiver should be re- 1000 cps on the left and right selector aligned using the manufacturer's instruc- WdNiW 11/11( switches and adjusting their respective tions. The generator will provide all the level controls to the same voltage.) If signals that are necessary for the realign- IRRADIATED no signal can be obtained from either ment. speaker, proceed to step 2. The MX129 is housed in an all -steel 2. Feed the mono signal from the case with a removable cover. A corn - Polyolef in Shrinkable Tubing "Comp. Out." into the receiver at the partment is provided for the attached detector output and balance the speak- cables and other accessories. Internally, PENNTUBEtV ers. If there is still no signal from either its 19 transistors, 9 diodes, and 76 -kc. speaker, the trouble would be some- crystal are mounted on a 6"x8äí " print- from thing associated with both channels; ed wiring board. Removal of four screws PENNSYLVANIA "B +," for example. If the speakers can permits folding back the board, pro- FLUOROCARBON be balanced at this point, the trouble viding easy access to all components COMPANY must be in the tuner, i.f., or detector. and circuitry. Generator weight is a 3. After the receiver has been bal- scant 73s pounds. Price is $169.50. 2:1 shrink ratio. Meets all applicable Bird Model 6154 R.F. Wattmeter specifications. For copy of manufacturer's brochure, circle No. 64 on coupon (page 15). Write for product data sheet and free sample ONE of the most important param- is able to absorb the full power output. NOW! eters of transmitter performance is Power can then be measured by rectify- all a known fraction of the r.f. PENNSYLVANIA r.f. output power. In addition to deter- ing or FLUOROCARBON CO., INC. mining economy and range of broadcast- voltage across this resistor and calibrat- Holley Street & Madison Ave., ing operations, power output measure- ing the meter scale in watts (P =E' /R, Clifton Heights, Pa. ments are often demanded by the FCC and R is a known constant). Phone: (215) MAdison 2 -2300 for regulations. To The new Bird Model 6154 Termaline® TWX: 215 -623 -1577 compliance with r.f. wattmeter -load was de- E uod Deal. Room 5710 Empire State Bldg. N.Y. 1, N.Y. make accurate and meaningful measure- absorption ments, the transmitter or the coaxial signed for transmitter maintenance and TEFLON FEP One source for: Shrinkable transmission line must be terminated in repair at mobile and base stations and at (Penntube-II'SMT) the proper characteristic impedance - service shops. It has an extended fre- TEFLON; TFE IRRADIATED from 25 -1000 mc., cover- Shrinkable Polyolefin Shrinkable mostly 50 ohms -by a non- radiating r.f. quency range (Penntube -I -E) ( Penntube.) dummy load which maintains its value ing the 25 -50 mc., 150 -174 mc., 450 -470 *DuPont Res. T. 2. tPenna, Ftuoroearnon Reg. T.M. over the frequency range of interest and mc., and 950 -mc. bands in one unit with- CIRCLE NO. 134 ON READER SERVICE PAGE WORLD 66 ELECTRONICS

www.americanradiohistory.com "Until just recently, I have been somewhat skeptical about low priced transistor amplifiers. However, after testing and listening to the Heath AA -22, I feel it is time to revise my opinion. This remarkable amplifier can easily hold its own against any amplifier - tube or transistor anywhere near its price range." JULIAN D. HIRSCH, Hi Fi Stereo Review, Nov. '64

Heathkit® 40 -Watt Transistor Stereo Amplifier 9995! Mr. Hirsch Went On To Say: "It is the gloves. I operated it at fill power for long embodiment the "WILL GET ANY STATION THAT of so- called `transistor sound' periods, and frequently overdrove clean, sharply it merci- CAN POSSIBLY BE PULLED IN" - defined and transparent. lessly, without damage to the tranrsistors, and It has the unstrainec/ effortless quality that with no change in its performance measure- is sometimes found in very powe,Jitd tube ments" .. "One amplifiers, of the best things abort or in certain expensive transistor the Heath AA -22 amplifiers." is its price, $99.95 in kit "The AA -22 is almost unique form, complete with cabines." among amplifiers at or near its price, since it delivers more than its rated power over the Let's Look Closer! The AA -22 provides 40 entire range watts continuous, 66 watts IHF music from 20 to 20,000 cps" . power Matching AM /FM /FM Stereo Tuner "The at +I db from 15 to 30,000 power response curve of this amplifier cps. Features 5 The above quote comes from July '64 issue of is one stereo inputs to handle mag. phono, of the flattest I have ever measvarecl" . stereo - Radio- Electronics. mono tuners, "Its RIAA piano equalization was one of the tape recorders, & 2 auxiliary The matching AJ -33 tuner features a built sources. -in most precise I have ever measured" ... "In- There are 4, 8 & 16 ohm speaker stereo demodulator; AGC for steady volume; ternlodulation distortion was about 0.5% outputs plus tape recorder outputs; a 5- AFC for drift -free reception; stereo indicator up position to 10 watts, and only I% at 38 watts per selector switch; 3 position mode light; stereo phase control for maximum separ- channel, with both channels driven" ..."The switch; dual -tandem control; bass & treble ation, minimum distortion; filtered stereo outputs; hunt and noise of the amplifier were inaudible" controls. tuning meter; flywheel tuning; voltage regulated power supply; illuminated slide -rule ..."Hi Fi /Stereo Review's kit builder reports Get Full Details Free! Simply use coupon dial; and pre- built, prealigned FM "front - that the AA -22 kit was above average in "huild- below. Or better yet, ability" "In order both the AA -22 end=' tuner and AM -FM I.F. circuit board ... testing the AA -22, I most Amplifier & its matching AJ -33 tuner now! for fast, easy assembly. appreciated not having to handle it with kid Kit AA -22, Amplifier, 2_? lh.s. $99.95 kit AJ -33A, Tuner, r 17 lis 599.95 HEATH COMPANY, Dept. 15 -12 -5 Benton Harbor, Michigan 49023 FREE 1965 CATALOG! In Canada: Daystrom, Ltd., Cookeville, Ontario

Enclosed is $ See these and over 250 other plus shipping. Please send Kit(s) exciting Heathkits available in Please send Free 1965 Heathkit Catalog. easy -to -build kit form. Save 50% or more by doing the easy as- Name sembly yourself! Send for your (Please Print) free catalog today! Address

City State Zip L Prices 8 specifications subject to change without notice. HF179 J December, 1964 CIRCLE NO. 187 ON READER SERVICE PAGE 67

www.americanradiohistory.com ha/li°'a fi e rs qua/», is the BIG NEWS in TEST INSTRUMENT KITS ... and hallicrafters engineered quality means outstanding specifications and performance . . . plus simplified construction!

NEW "Fail- Proof" soldering NEW assembly ease. Mechan- terminal strips simplify mak- ical parts are riveted to the ing of positive connections. chassis at the factory. CAPACITANCE DECADE voima RESISTOR DECADE Kit HD -2 Kit HD -1 Use to substitute known- Ideal for experimental and ' value precision resistors service work requiring pre- _ in a circuit. Resistors are cision capacitors. Sixteen - one -watt, 10 %. Twenty - commercial slide switches give total variability in eight commercial slide switches give total vari- out charts or calibration adjustments. 100 pf steps. Uses silve mica capacitors and long ability in 1 -ohm steps. Range: 1 ohm to 10 The usefulness of this lightweight port- lasting stable defilm capacitors. Range .0001 to 1.0 ohms in seven decades. Price $14.95 mfd in four decades. Price $14.95 able instrument is further increased by R.F. GENERATOR Kit HG -1 four full-scale power ranges in place of Generates frequencies from 50 kc. CONDENSER TESTER Kit HC -1 to 55 Mc. in six steps. Calibrated the usual two: 0 -5, 0 -15, 0 -50, and 0 -150 Handy service bench instrument for harmonics in two steps from 55 watts. This checking unknown condenser and re- permits up -scale measure- Mc. to 220 Mc. Low frequency sistor values under operating condi- ments of low- output transmitter, circuit range exceptionally stable. Accu- tions. Has precision tuning eye for 11/2 % of adjustments prior to final full -power ap- easy operation. Four capacitance racy the reading. R.F. output .1 -volt. Bandswitch as- ranges: 10 mmf to 2,000 mfd. plication, in addition to continuous read- sembly pre -wired and calibrated. Three resistance ranges: 0.5 ohm Price $29.95 ings up to 150 watts. The load resistor, to 5 megohms. Price $29.95 xvhich is surrounded by a special coolant, VACUUM TUBE VOLT MILLIAMETER 5 -INCH OSCILLOSCOPE Kit HO-1 Kit HM -1 is so well matched to the 50 -ohm trans- A perfect scope for servicing color Has an exclusive built -in milli - mission line that v.s.w.r. ( voltage stand- TV sets. Has full 5 Mc. bandwidth. ameter circuit, available at the ing -wave ratio) remains below 1.1, i.e., Tube is 5 UPI. One -volt peak -to -peak turn of a switch. Illuminated meter source attenuator permits voltage and separate front panel On -Off reflected power is less than 3.; percent to Y C CC measurements switch. Has seven AC, DC voltage c c over range of 10,000 1000 mc. Selected crystals insure full - rc c it to 1. Retrace blanking amplifier pro- ranges, from 1.5 to 1500; seven f._. vided. Phasing is continuously vari- ohmeter ranges, 0 to 1,000 meg- scale measurement accuracies of 5% to able from 0 to 140'. Has two axis ohms; and six milliameter ranges, 500 mc. and 107 to 1000 mc. (beam) modulation. Price $84.95 1.5 to 500. Price $29.95 The coaxial load resistor, mounted BATTERY ELIMINATOR Kit HP -1 within a finned radiator, is detachable Reliable source of 6- or 12 -volt DC power for servicing car radios, including transistor and "hybrid." AC from the meter housing for more conven- ripple less than .25 %; exceptionally low. Voltage ient reading. The voltmeter circuit con- ranges 0.8 volts and 0 -16 volts. Also use as battery sists of two capacitive dividers, one for charger. Has voltage and current panel meters. Price $49.95 the X1 and the other for the X10 range, two sockets for the plug -in crystal, an r.f. your Authorized at filter circuit (R1 or R2 and C1), and a Look s /licrafters Kit this P IaV Ha :30-microampere meter, Switch S1 and Headquarters./ meter -shunt resistor R3 effect a 3:1 sensitivity change. hall/crefters The Model 6154 accurately indicates carrier power with c.w., F \I, A \1, and K,ito Ailuttek TV modulation envelopes. It weighs only For FREE Catalog, write Dept. 14 -L, 5th & Kostner Aves., Chicago 24, III. 8 lbs. and measures 6:!k "x 4 "x 121:'í6". NO. 186 ON READER SERVICE PAGE CIRCLE The input connector is a female type N, and to u.h.f. (SO -239) is ATTENTION an adapter CLASSIFIED ADVERTISERS available for $2.25. Price is $265. Be sure to get YOUR ad in the 1965 COMMUNICA- By changing the location of the crys- B. S. Degree in 36 months TIONS HANDBOOK and 1965 ELECTRONIC EXPERI- MENTER'S HANDBOOKS. Don't miss this great tal diode, a different amount of r.f. Small professionally-oriented college. Four- quarter opportunity to reach a buying audience that will energy is picked up. As a result the year permits completion of B.S. Degree in three respond for an entire year. sensitivity of the meter is altered. c cars. attendance Sumner optional. Engiricrur_!: 1965 COMMUNICATIONS HANDBOOK ....75Ç Word Electrical ( electronics or power option), Mechan- 75f ical, Civil. Chemical. Aeronautical. Bu-,incsa Ad- Spring 1965 ELEC. EXP. HANDBOOK Word nriui.,l rat ion: General Business. Accounting. Motor Fall 1965 ELEC. EXP. HANDBOOK 75Ç Word Transport Admini,tration, One -oar Dr;rttin SPECIAL COMBINATION RATE FOR ALL .$1.55 Word Design Certificate program. Graduate placement COMBINATION RATE FOR COMMUNICATIONS outstanding. Founded 1884. Rich heritage. }..x- AND Spring ELEC. EXP. HANDBOOKS cellcnl laculty_ Small classe;. 2011 -acre canon,. $1.10 Word Well equipped labs. New library. Residence halls. ONLY 110dcsi costs. Enter Jan., Alarch, June, Sept. or CLOSING DATE FOR COMBINATION RATES: Cu hrlu, nid l' icre Bruck, nuite Dircrtor of Adrnis- Nov. 25, 1964 ,i,,,I today. Send Order and Payment Today to: Martin Lincoln, Class. Adv. Mgr. Ziff -Davis Publishing Co. 1 Park Avenue TRI -STATE COLLEGE New York, New York 10016. 16124 College Avenue Angola, Indiana WORLD 68 ELECTRONICS

www.americanradiohistory.com Portable TV Sets SOLDERING TIPS (Continued from page 30) FOR HI -FI KIT BUILDERS both the second anode voltage ( 8 kv. ) and the voltage used to focus the CRT; and an additional winding on this transformer supplies the horizontal frequency pulse for use by the horizontal sweep a.f.c. and the keyed a.g.e. systems. Although the "B ±" for the portable TV sets is. approximately 12 volts, either from a battery or a.c.- powered d.c. source, there are many cases where a much higher voltage is required. Such a case is the video amplifier that must accept approximately 1 volt of video from the detector and amplify it to approximately 40 to 50 volts for use by the CRT. The video amplifier shown in Fig. 5, used in the Realtone Model TR -6867 (6 -inch) TV set is typical of the video amplifiers found in most sets. The 1 -volt video signal is applied to the p -n -p transistor, and the relatively high emitter voltage is generated by taking the signal developed across the horizontal yoke (approx. 90 -v.) and rectifying it with a silicon diode. The 15 -kc. pulses are then filtered and used as the d.c. source. AVOID TOO MUCH HEAT High heat can damage components. Use low Future Developments heat for soldering, and a pair of long -nose pliers to hold the wire. Pliers act as a heat What of the future? With the rapid strides now being sink and prevent overheating. made in the fabrication of integrated circuits, it may not be too far in the future before we see an almost fully integrated TV set in which a series of tiny monolithic chips, thin -film devices, and hybrid circuits, combined with a new approach to CRT design, may lead to a pocket portable TV set. The limiting factor here would be the size of picture that the public would buy in any worthwhile quantities. The introduction of integrated circuits would make not only for a smaller set but would improve the circuit reliability to the point where service would be minimal. The integrated circuits would be so arranged that each circuit section (video i.f., sound i.f., sweep sections, etc.) would be on a transistor -like header plugged into a miniature socket. If one of the circuits should fail, then a tube- tester- like device could be used to check the individual circuits, the faulty one isolated and thrown away (integrated circuits cannot be repaired at any reasonable cost) and a new one inserted in the stage. With the use of integrated circuits, complex and physically USE A DUAL HEAT GUN bulky circuits would be a thing of the past. Then it would A Weller Dual Heat Gun has 2 trigger positions. One provides low heat for electronic be possible to make small- screen portable color sets. Cathode_ connections: the other gives high heat when ray tubes may undergo drastic electrical and mechanical needed. You switch instantly to the right changes and miniature CRT's of the future may not even temperature for the job. look like present ones with a screen at one end and the electron gun at the other. With the continued research into The greatest time -saver in hi -fi kit building microminiaturization presently going on in other areas of is a Weller Dual Heat Gun. Tip heats in- electronics, the consumer market will also profit. stantly ... no waiting. Spotlight illuminates

Fig. 5. The video amplifier used in the Realtone set is typical your work. Long reach tip gets into tight of most other sets. "B -" is the rectified horizontal pulse. spots and permits soldering with pinpoint RORIZ. -55v. PULSE accuracy. 90V. P -P A Weller "Expert" Kit includes 100/140 watt dual heat gun, 3 soldering tips, tip - changing wrench, flux brush, soldering aid r 000` ---1 and solder, in a plastic carrying case. Model CRT PU INPUT -NVNMI- 8200PK -$8.95 list. Weller Electric Corp., N Easton, Pa.

BRIGHT- NESS B+ (300V.)

CONTRAST i'.FOCUS

+12V WORLD LEADER IN SOLDERING TECHNOLOGY December, 1964 CIRCLE NO. 235 ON READER SERVICE PAGE 69

www.americanradiohistory.com New SCR Developments Small (250 ma. or less) gate -con- (Continued from page 27) trolled p -n -p -n devices have been available for some time. These devices behave like a conventional SCR during transient -susceptible one. This makes turn -on and conduction and as a linear the SCR comparable in self -healing charge controlled amplifier in the turn- properties to the ignitron, selenium rec- off mode. A charge (current pulse) in- tifier, and other older self- protecting de- troduced at the gate electrode cancels vices. the charge caused by the load current As a sidelight, controlled -avalanche and the device turns off. SCR's can be used in place of high -volt- A new type of power SCR is based on age, high -current zener diodes and as the operation of these low- current protection devices for other circuits in switches. Gate -controlled switches that certain cases. can switch 5 amps at 400 volts have recently become available. A positive gate Transient Immunity pulse turns them on and a negative gate A closely related problem of SCR's is pulse turns them off. They will also turn transient turn -on. A voltage much lower off when the supply voltage is removed, than the forward anode breakover volt- just like an ordinary SCR. age of the SCR could turn the SCR on if Quite a substantial pulse of current is the rise time of the applied forward volt- required for turn -off in the present mod- Get age was short enough. This is called the els. Turn -off current gain is around ten. "dv /dt" problem. As an SCR turns on in Actually, this low current gain in no way your a short time and produces a transient, it limits the utility of this SCR, for consid- can easily turn on other SCR's on the erable power gain is achieved during own same power line. The effects of this on a turn -off. The turn -off voltage only has to production line could range from amus- be 3 volts or so, but will directly switch copy! ing to disastrous. The traditional means 400 volts. Also, the turn -off signal has of eliminating dv /dt turn -on was to iso- to exist for only a small part of a milli- late the various circuits with transform- second. The usual method of turn -off is It's only ers or to use inductance to limit the rate to discharge a capacitor into the gate, of rise of applied current. Thyrite and as the required high -current pulse is other varistors were also used. easily provided in this way. The gate The new SCR's are virtually dv /dt- may also be turned off by direct connec- The 1965 STEREO /HI -FI DIREC- volt- TORY is so valuable, even your best proof. The rate of rise of anode voltage tion to a low- impedance negative friend won't be able to wrest your must be faster than 200 volts per micro- age using a transistor, four-layer diode, copy away! second before dv /dt turn -on can occur. or other switch. In 180 photo -packed pages, you get Transients on industrial lines simply are There are quite a few possibilities for authoritative prices and performance not usually that fast. The exact manufac- this device which heretofore had no data on over 2,000 components from high -voltage counterpart. Two typical 170 manufacturers! turing techniques required to make an circuits are shown in Fig. 3. Small gate This all -new Buyer's Guide gives you SCR dv /dt -proof are not easily ex- vital statistics on speakers, tuners, plained and are proprietary with cer- pulses will operate the SCR as a d.c. receivers, turntables, changers, cart - tain companies. latching switch. Pulse it to turn on, pulse ridges-on every hi -fi component man- Taken together, controlled avalanche it to turn off. A 2 -kw. load may be con- ufactured today! Use it to compare immunity make the SCR more trolled with two small, low- energy gate for -dollar, fea- and dv /dt similar items, dollar- A second possibility is to use the ture -for- feature, before you buy, and transient- immune and self -protecting. pulses. avoid excessive prices, disappoint- These are essential features of any indus- gate controlled SCR in a voltage -variable ment, and costly mistakes! trial high -current control system. power supply. By varying the ratio of on- The 1965 STEREO /HI -FI DIREC- These techniques are expensive and, time to off -time, various amounts of load TORY also contains...an up- to -the- at present, are available only on pre- power can be provided. This is done in -fi in minute listing of every hi dealer where this type of protec- a rapid off -on- off -on- off -on sequence. Fil- the country...and a complete run- mium devices down of all the FM stereo multiplex tion is mandatory for the intended appli- tering this output waveshape retains only stations in the U.S. and Canada! cation. Generally, 117 -volt circuits are the d.c. component, providing a smooth, But most important -if you want to immune from either problem due to the continuously variable output. As this get top value on every hi -fi component "softness" of most 117 -volt lines. As a SCR operates in the switching mode, the you buy during the next twelve result, controlled -avalanche and high efficiency of this design is very high and months... dv /dt devices are confined to applica- can approach 100 percent. The heat pro- tions requiring 220 -volt or higher line duced is substantially less than that pro- SEND JUST $1 NOW FOR YOUR COPY OF voltages. duced in vacuum -tube or transistor dissi- THE 1965 STEREO /HI -FI DIRECTORY pation- type regulators. A small differen- Gate Turn -Off SCR's tial amplifier will adjust the output to r -- FILL IN AND MAIL THIS COUPON RIGHT NOW! --, The conventional SCR is turned on by hold the voltage constant for varying I Ziff-Davis Service Division, Dept. SH a one. I 589 Broadway, New York, N.Y. 10012 a positive current pulse at its gate. The load, making the supply regulated -off SCR I Please send me a copy of the 1965 STEREO/ HI -Fl only way it can be turned off is by re- The fabrication of a gate turn I DIRECTORY. My dollar, plus 15C for shipping and anode voltage. is much more difficult than an ordinary I handling, (25C outside U.S.) is enclosed. moving or reversing the In many cases, this is either inconven- SCR. Because of this, they are not, at There are a number present, low -cost devices and probably name ient or impractical. please print EW-124 of applications for a gate -controlled never can approach the price of the switch which can turn the load current economy SCR's. But, the circuit simpli- 1 address off as well as on simply by applying a fication and the new circuit possibilities cost using stare zip code J negative current pulse to the gate. can reduce over -all equipment L`ty 70 ELECTRONICS WORLD

www.americanradiohistory.com the gate- controlled SCR, thus justifying the higher cost of this component. Bilateral SCR's All regular SCR's are unilateral -they only work in one current direction. To operate off the a.c. line, SCR's must be ROHN used in pairs or the line must be inverted with diodes. Other alternatives are half- wave, half -range operation and mechanical switching of an ordinary diode to provide full-range control. The most Famous /Nme in Bilateral SCR's eliminate this problem. They simply go in series with the a.c. TOWERS of ALL ONDÇ.¡ line and the a.c. load. They work in Here are the advantages you get either current direction and turn off auto - when you insist on matically every a.c. zero. There are two ROHN TOWERS newly introduced devices that accomplish bilateral a.c. control at substantial LARGEST FULL RANGE OF TOWERS -you can get anything from home TV and amateur radio towers to power levels. heavy -duty communication and micro -wave towers. Transitron's "Biswitch" is a gateless Included are 500 foot self- supporting towers, 1,000 foot guyed towers, "fold- over" and crank -up towers. bilateral SCR. It is turned on by ava- Regardless of your needs, ROHN can supply it. lanche breakdown. This is done by ap- UNQUESTIONED LEADERSHIP IN DESIGN AND MANU- plying a 400 -volt spike to the "Biswitch" FACTURE -you get the latest in advanced tower engi- to it neering. All communication towers are engineered turn on. An autotransformer steps to EIA specifications, and are proved by thousands up a small trigger pulse to trigger the of installations. No other manufacturer can surpass the quality and fine reputation Biswitch. As the Biswitch is turned off of ROHN. during triggering, very little trigger en- QUALITY MATERIALS AND WORKMANSHIP -Only highest quality steel is used which fully meets the speci- ergy is required, giving a very high turn - fications for the job. ROHN towers are hot -dipped on gain. Fig. 4A shows a galvanized after fabrication -a feature ROHN pio- dimmer circuit neered! using a Biswitch. With proper heat -sinking, it can control 600 watts SERVICE WHEREVER YOU WANT IT -ROHN represent- of light or atives are world -wide. Complete erection service for motor load. communication systems, broadcasting, micro -wave, General and other needs is available; also competent engi- Electric's "Triac" is a bilateral neering service to help you. gate controlled SCR. Using this device, Settle for BEST a full -range the in TOWERS -ROHN -today the dimmer or power -tool con- world's largest, exclusive manufacturer of towers of trol can be built using only four parts. all kinds! The circuitry cost, using a Triac or Bi- Also available: Rohn Lighting Kits, Microwave Pas- switch, is about the same. The Triac is 4 sive Reflectors, Tower Installation Service and En- gineering Assistance. Representatives World -Wide more expensive, but requires no trigger to Serve You. transformer. A Triac dimmer is shown in Fig. 4B. For your needs. contact your local ROHN salesman, For more information on new SCR's, distributor or dealer; or write direct for information. such as the ones discussed in this article, SEND THE HANDY COU- 1 their Send me complete literature on the following ROHN Products: circuits, and their capabilities, con- PON INDICATING YOUR Hems TV Towers Amateur Towers sult manufacturers' data sheets and de- NEEDS Communication Towers AM-FM Broadcasting Tower! Micro -Wave Towers Government sign- information supplements. Name ROHN Firm Manufacturing Address

Co. City state BOX 2000 "World's Largest EXCLUSIVE Manufacturer of Towers; designers, PEORIA, ILLINOIS engineers, and installers of complete communication tower systems." J CIRCLE NO. 210 ON READER SERVICE PAGE name address SEND ELECTRONICS WORLD city zip state Check one: 3 years for $12

EVERY I,Itic(Ioliits 1lorltl 2 years for $9 1 year for $5 In the U.S., and possessions. MONTH Payment enclosed Bill me Foreign rates: Canada and Pan American Union countries, add 50¢ per year; all other foreign countries, add $1.00 per year. Il New ri Renewal Mail to: ELECTRONICS WORLD Dept. 0029, 1255 Portland Place, Boulder, Colorado 80301 December, 1964 71

www.americanradiohistory.com ' cisToR DUAL CONVERSION LAFAYETT E FILTER RADIOREE! ELECTRONICS 1965 CATALOG No. 650 Featuring Everything Over 500 Pages' in Electronics for

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from the "World's Hi-Fi & Electronics Center" Stereo Hi -Fi -All Famous Brands Radios, TV's, and Accessories Plus Lafayette's Own Top -Rated P.A. Equipment; Intercoms BUY ON TIME Components Cameras; Optical Goods - Citizens Band -Transceivers, Marine Equipment; Use Lafayette's Walkie- Talkies and Accessories Auto Accessories famous Easy -Pay Tape Recorders Ham Gear Musical Instruments; Tools; Credit plan ... up to Test Equipment Books and MUCH MORE 24 Months to Pay See the Largest Selection in Our 44 -Year History 9395

New LT -325 AM /FM Multiplex Tuner combines simplicity, flexibility, and superb styling. 20 -Tube performance provides a great variety of features, 4995 19950 including a new audible tone "Stereo Search Sys- tem." Imported, 99- 0001WX. Model LA -224 24 -Watt New LR -800 70 -Watt Complete Stereo Amplifier combines AM -FM Stereo Multiplex Re- high performance, beautiful ceiver features a tuned nuvistor styling and low price to give "front -end" and an FM "Stereo - HEADQUARTERS you a truly brilliant stereo Search" multiplex indicator. performer. Full control fa- Excellent sensitivity, frequency cilities for integration with response, and low distortion FOR THE HI -FI all hi -fi music sources. Im- specs. Imported, 99- 0005WX. ported, 99-001 7WX. ENTHUSIAST

Lafayette 2- Station Transistorized Inter- com features inter -unit tone calling, Model SK -300 "Dec- pushbutton operation and beautiful or 5- -ette V" Slim styling. A single 66 foot plug-in connect- Speaker System util- ing cord allows for fast and simple hook- izes the 5 most im- up. Powered by one inexpensive 9 -volt portant speakers you battery. AC power supply /battery charger may ever own. Four available. Imported, 99-4526. 61/2" woofers and one 21/2" cone -type tweet- er designed to give Model RK -142 Deluxe Portable Tape Re- optimum performance corder perfect for the home, school, or in a 41/4" thin oil office. Records and plays 1/2 track mon- walnut enclosure. Re- aural at two speeds. Specically de- sponse from 50 to signed lever type motion switch gives 18,000 cycles. Im- fool -proof operation. Complete with dy- ported, 99- 0008WX. namic microphone, connecting cables, 3995 and empty 7" reel. Imported, 2 for 99- 1512WX. 78.50

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e 2295 6450 t 5995 Model HA -63 Short- "Explor -Air" Deluxe Three New Deluxe Lafayette 2595 wave Receiver is an excel- 4- band short the begin- wave receiver kit -an ideal Receivers for monitoring The New Model HA -115 lent choice for police, fire department, air- ning shortwave listener .or way of introducing yourself audio compressor amplifier craft, civil defense, or com- instantly and automatically novice amateur. Covers 550 or your children to the fas- communications. in 4 bands and cinating world of electronics mercial increases the "talking pow- KC to 3Omc 10 -Tube performance fea- - shortwave listening. De- er" of your citizens band features electrical band and tures high sensitivity, vari- 7 tailed step -by -step instruc- transceiver by increasing spread on all frequencies. able squelch, and fully Tube circuitry gives out- tion book makes this kit a the average modulation of tuned RF stage. Imported. the transmitter section. standing selectivity and pleasure to build. 19 -0905. 99-2525WX Model HA -50 30.5OMe CB sensitivity. Imported, Cabinet available for 2.85. Model HA -55 108.136Me 99-2527WX Works with all popular 99- 2534WX 19-0906 Model HA -52 152.174Mc 99.2526WX units. 42-0117.

2595 19" Lafayette Stain- less Steel CB 2 for 2 for Mobile Antenna 49.95 38.75 10" -an outstanding buy with out- HE -29C 9 -Tran- Model HA -85 6- 2 for standing fea- sistor Walkie- Transistor "Walk - tures. Chrome Talkie provides ie- Talkie" trans- 21.00 plated swivel ball two -way com- mits and receives mount base per- munications up to 1.5 miles. up 1 to mile. Ideal for sports, The HA -70A -a wired pocket - mits mounting Powered by six penlight bat- boating, construction and size 3- transistor walkie- talkie on any surface. teries with life expectancy recreation. Complete with with countless exciting short Lug terminals of 55 hours. An AC power leather case, earphone, bat- range applications. for easy hook -up supply Complete is also available. teries, and crystals for the with crystal, carrying case, to coaxial cable. Specify channel. Imported, channel of your choice. Im- and 9 -volt battery. Imported, Imported, 99.3020CL. ported, 99- 3013CL. 99-3011L. 695 99- 3034WX.

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SEND TODAY FOR YOUR FREE 1965 CATALOG LAFAYETTE RADIO ELECTRONICS LAFAYETTE RADIO ELECTRONICS Mail Order and L. I. Sales Center Dept. RL -4 P.O. Box 10 111 Jericho Turnpike, Syosset, L. I., New York Syosset, L.I., N.Y. 11791 Store! Send me the FREE 1965 Lafayette Catalog 650 I New! New York City New York, N. Y. Brooklyn, N. Y. 71 West 45th St. 100 Sixth Ave. 2265 Bedford Ave. $ enclosed; send me Jamaica, N. Y. (Prices do not include shipping charges). Bronx, N.Y. Scarsdale, N. Y. Paramus, N. J. 165-08 Liberty Ave. 542 E. Fordham Rd. 691 Central 182 Route 17 Name (Park) Ave. Newark, N. J. Plainfield, N. J. Boston, Mass. Natick, Mass. Address 24 Central Ave. 139 W. 2 St. 584 Commonwealth 1400 Worcester St. City Ave. ------State - - - - -Zip - - - - December, 1964 CIRCLE NO. 194 ON READER SERVICE PAGE 73

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PAGE 74 CIRCLE NO. 194 ON READER SERVICE ELECTRONICS WORLD

www.americanradiohistory.com ORGAN KIT USES ARE YOUR RECORDS IN GOOD SHAPE? DIODE SWITCHING Diodes replace mechanical contacts and act as variable resistors in percussion circuitry in Heathkit organ.

OLLOWING the successful introduction of a low -cost transistor organ kit two years ago, the Heath Co. has recently announced a new, more sophisticated model. Designated as the "Heath - kit" GD -983, the new model is a kit version of the Thomas "Coronado" BL -3. HI -FILE RECORD CASES Until now, when an electronic organ These handy record cases hold your albums offered an array of electronic equivalents safely and neatly on your bookshelf. They're of 16 -, 8 -, and 4 -foot pipe -organ regis- the perfect answer to your record storage problems! ters, a minimum of one mechanical so attractive: rich library binding of simulated switch or contact had been required for leather, tooled in 16K gold. They make handsome each register on each key. Such switches additions to any shelf. And there are six colors require initial adjustment for to choose from: black, brown, maroon, red, blue precise and green. proper sequence as well as periodic no chance of warping or breakage: albums maintenance. Even when properly ad- are held in a vertical position, thus preventing justed, such switches may cause transient damage. noises such as "popping" and clicks. albums stay clean and neat: each case is In the new organ, where more than dustproof, holds twenty of your 12" LP's in their original jackets, with a divider for separating rec- one register is used, the traditional mul- ords by artist or category. tiple mechanical switches have been re- ploved in the kever circuit board. This handy size: 13" high, 121/2" wide and 31/2" deep, placed with miniature silicon diodes. In may sound like a formidable do -it -your- so they can accommodate your multiple- record albums, as well. contrast to other electronic organs, where self project, but it isn't since this par- albums are easily accessible: open back en- a performs the - depressed key actually ticular circuit board is supplied factory ables you to read titles on the spine of albums for switching of multiple signals, the CD- assembled and tested, ready to install. fast selection. 983 uses a single contact on each key The pedal clavier is also diode which merely applies a forward biasing switched, and has its own sustain cir- Ziff -Davis Publishing Co., Dept. SD 1 Park Ave, New York 16, N.Y. EW 124 voltage to a group of diodes. The signals cuitry. Please send me Hi -File record cases, from the conducting groups of diodes There are 12 tone generator circuit at $3.50 each, 3 for $10. Color choice, check are fed to their respective passive filters, boards, each one consisting of an os- box. and selected by means of the usual tab cillator, and three bistable frequency black brown maroon red blue green voicing switches. dividers. In this particular model, four different The percussion section is also quite I enclose registers of stops are offered on the unique. The user may (1) percuss swell Name sipper or swell keyboard which has 44 flute voices, while the string, woodwind, Address keys. Thus there are 176 diodes used reed, and diapason voices sound nor- in the switching. The benefits this City Zone State of mally; (2) percuss the swell string, Shipped prepaid Fully guaranteed electronic method of switching are woodwind, reed, and diapason voices many. In addition to the elimination of while the flute voices sound normally; the cumbersome mechanical contact (3) percuss all voices on the swell man- SCIENCE/ method and its problems, there is the ual; (4) percuss voices of the great man- complete absence of transient noises due ual; and (5) percuss voices of both ENGINEERING to the "variable- resistor" effect of the rise manuals. The repeat percussion adds a ASSOCIATE & BACHELOR OF SCIENCE PROGRAMS and decay times of the diodes in going strumming effect to create the sounds into fastest -growing fields of Physics, Math- from non -conducting to conducting of mandolin, banjo, and marimba. A Get ematics, Engineering (Nuclear, Electronic, Elec- states. This same microsecond time lag variable control adjusts the rate of re- trical); also Engineering Technology (Nuclear, not only precludes transient noises, but peat as desired. Electronic), Optional four -quarter, all -year also adds to the realism of the organ by Playing features include 17 organ schedule allows finishing four -year B.S. degree making its attack action similar to that voices, two 44 -note keyboards, a built -in programs in 3 yrs.; A.S. degree in 2 yrs. A.A. degree in Electronics Technology in 11/2 yrs. Send - of a pipe organ. The reliability of solid two -speed Leslie speaker plus a 2 -unit for Catalog W -12. Winter Quarter starts Jan. 4th. state techniques is firmly established and main speaker system, 28 notes of chimes, therefore this important characteristic 13 -note heel and toe pedalboard, reverb, NORTHRIDGE COLLEGE OF SCIENCE & ENGINEERING 18758 Bryant St., Northridge, Calif. accrues to the benefit of the owner in vibrato, color -tone attack, repeat and terms of long, trouble -free operation. sustain percussion, stereo chorus con- BARGAIN FREE: GIANT In addition to the switching diodes, trol, treble accent, manual balance, pedal SENSATIONAL NUNI/N6? each key has a blocking diode to prevent volume, expression pedal, headset out- ELECTRONICS feedthrough of a signal via associated let, 75 -watt EIA peak power amplifier, CATALOG wiring, and a sustain diode which and walnut -finished hardwood cabinet charges a capacitor for the desired decay and matching bench. The complete kit HENSHAW TV SUPPLY time. In total, there are 264 diodes em- sells for $849. 3617 'ROOST KANSAS CITY, MO.

December, 1964 75

www.americanradiohistory.com FM- 0.62 mv. and at 200 mv. it was 0.29 mv. EVERYTHING Stereo Demodulator YOU NEED ABOUT TO KNOW (Continued from page 35) High TAPE RECORDING -Gain Tuner Modifications 191IINI/stpreolipvi P! 1 Although the multiplex circuit de- stereo multiplex generator to the input of scribed in this article operates satisfac- 65 TAPE the adapter. torily with tuners requiring a minimum RECORDER 20. Attach the a.c. v.t.v.m. to the of eight microvolts (antenna input) for right output. limiting, problems may be encountered Bow T- -ANNUAL UAL 21. Set the stereo multiplex generator with higher gain tuners, that is, tuners RECORDER BETTER to the left channel only. Adjust L4 for requiring less than three microvolts TAPES TIPS for RECORDING SELECTNTHRIGHT null on v.t.v.m. (only slight retouching limiting. When such tuners are used, the TAPE RECORDING ROW ROME TAPE of L4 is COPYING necessary). Record separation noise immunity, SCA rejection, and in- THE RECORDS IN TRUTH ABOUT ONTO THE (right channel). put- impedance characteristics of the TO BARGAIN TAE TAPE.ßOW 22. Measure left -channel separation. original circuit should OWN SOUND be modified. The PLUS A Left- and right- channel separations required changes can be readily attained should Of STEREO be within 3 db. (A slight com- by the addition of a stage and replace- TA promise in L4 adjustment may be neces- ment of the single -tuned transformer sary to provide equal channel separa- (L6) in the threshold amplifier with a tions.) double -tuned transformer. This consists 23. Connect FM tuner to demod- of two single -tuned windings ( TRW ulator input. 24. Connect the stereo multiplex gen- 12 VOLTS THRESHOLD erator output to the external modulation AMPLIFIER terminal of the FM signal generator; Know -all. frequency modulate a 98 -mc. signal 30% -it with a 1000 cps L =R signal. It's easy to be an authority on tape when 25. Set the FM generator for full you have a copy of Hi Fi /Stereo Review's limiting in the tuner. The indicator light 1965 TAPE RECORDER ANNUAL handy. will then be lit. SCA FILTER (LI) Look at the photo above. The special 26. Attach the a.c. v.t.v.m. to the articles listed on the cover of this 132 - right output. page factbook are just a few of the 23 27. Set the stereo multiplex generator complete features! You get expert tips to the left channel only and adjust L4 Fig. 4. Added stage for high -gain tuners. by the dozens, on equipment - making for null on v.t.v.m. (only slight adjust- better tapes- editing- copying -sound ment is required) . Record separation type 17558 primary and TRW type on everything you need to know about (right channel). 17557 secondary) coupled together with tape recording. Plus... 28. Measure separation in left chan- a 10 -pf. capacitor. The double -tuned ... a complete directory of stereo tape nel. (A slight compromise in L4 adjust- transformer achieves the desired noise recorders! Over 100 photos -complete ment may be necessary for equal right - immunity and increases the selectivity data on 230 models from thirty -three and left -channel separations.) of the 19 -kc. circuit. different manufacturers! All the model 29. Decrease the threshold poten- The additional stage is located at the numbers, specifications, dimensions tiometer to its maximum counterclock- input of the adapter, as shown in Fig. 4. and prices! All the important informa- wise position. The indicator lamp will With the emitter -follower mode used, tion you need to compare the latest tape then be extinguished. this stage supplies the required increase recorders, and select the finest one in 30. Set the FM signal generator out- in input impedance. The additional your price range. put for acceptable tuner quieting. Slowly stage is directly coupled to the pilot Published for the first time (by the edi- advance the threshold potentiometer separator by means of the SCA filter. tors of Hi Fi /Stereo Review ), the 1965 clockwise until the indicator lamp lights. In this manner, the high impedance of TAPE RECORDER ANNUAL is an indis- The demodulator will then automatically the SCA filter at resonance is used to pensable guide for everyone who wants switch to stereo operation at or above the fullest extent and, as a result, the better performance and greater versa- this signal level. increase in SCA rejection can be realized tility from his tape recorder. If you fit The performance of the demodulator without a change in the filter. this description ... was tested by means of the setup shown in Fig. 3. A portion of the results ob- SEND JUST $1 NOW FOR YOUR COPY tained are listed below. of the 1965 TAPE RECORDER ANNUAL Channel separation of stereo demodu- 1- -FILL IN AND MAIL THIS COUPON TODAY! -, lator (channel separation adjusted at WA4AUFI

1 : F35g1 I ZIFF -DAVIS SERVICE DIVISION Dept.TR 500 mv., kc.) At a signal level of 500 589 Broadway New York, N.Y. 10012 mv. r.m.s. channel separation was 34.2 5137 Please send me a copy of the 1965 TAPE db at 100 cps, 43.7 db at 1 kc., 26 db RECORDER ANNUAL. My dollar (plus 15C for at 10 kc., and 20.2 db at 15 kc. At a shipping and handling; 25C outside U.S.A.) signal level of 200 mv. r.m.s. at 100 cps is enclosed. the channel separation was 22.7 db, at Orkp 1 kc. it was 25 db, at 10 kc. it was 20.1 name please print db, and at 15 kc. it was 16.4 db. Harmonic distortion (signal level=

500 mv., 10% pilot): was 1.1% at 100 fíiw,vrE,9 address EW-124 cps, 0.9% at 1 kc., 1.3% at 10 kc., and 1.9% at 15 kc. "I don't give a hoot about Greenwich Mean city state zip code ! The output subcarrier residual with a Time! Right now it's Boston Bean Time and L (PAYMENT MUST BE ENCLOSED WITH ORDER.) --I modulator input level of 500 mv. was they're getting cold."

76 ELECTRONICS WORLD

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December, 1964 77

www.americanradiohistory.com Early Vacuum Tubes The lamp which Fleming used is (Continued from page 43) shown in Fig. 2. It is preserved in the Science Museum in London. With this lamp was found the first practical wire- filament were screened in a glass tube. less use for the Edison effect. I contains a small square of mica which Fleming named the Edison- effect can be interposed between the plate and lamp used to detect wireless signals an the filament. When the plate was "oscillation valve." His patent covers screened by the mica from the negative the application of the Edison -effect lamp leg of the filament, it was found that the to this particular use and to the circuits current stopped. relating thereto, and not to the lamp it- Much of a general nature was learned self. through these experimental years. Pos- After the successful experiments with sibly the most important general char- the lamps, Fleming had the Edison and acteristic of all the Edison -effect lamps Swan United Electric Light Co. make was the unilateral conductivity of these up a number of "oscillation valves" for lamps. Rectification of alternating cur- experimental purposes. Some of these rent at low frequencies had been ac- are shown in the bottom row of Fig. 1 complished in the laboratories utilizing and in Fig. 5. this unilateral conductivity character- On June 15, 1905 Fleming sent to istic. Marconi five of these experimental "os- By 1896 Fleming had about con- cillation valves" for trial. Marconi began cluded his Edison -effect experiments using these valves at once, to the ex- and these lamps were placed in a cup- clusion of all other detector types. Many board for storage, as no practical use more valves were supplied by Fleming M-mvu had been discovered for them. in 1905 and in 1906. In 1907 the British W W Ul/ IAAIL Fleming Valves Marconi Company began to manufacture these valves for its own use. In 1899 Fleming became a technical The British Marconi Company con- The advisor to Marconi. In 1900 he started tinued to use the Fleming "oscillation to assist Marconi in preparations that valves" in its receivers for many years. A were to lead to the establishment of 1912 Marconi receiver with its duplicate do-it-yourselfer's transatlantic wireless telegraph com- "oscillation valves" is shown in Fig. 4. munications. From these simple beginnings, the gi- In 1900 the most troublesome part of ant electron tube industry has grown. newest any wireless equipment was the detector. In those days the only detector of wireless signals was of the contact TIME SIGNAL CHANGED type, such as coherers and the like, THE transmitting clocks of radio sta. which were mechanically very unstable tions belonging to the National Bu- catalog reau of Standards (WWV, and subject to burn -out from the local WWVH, and transmitter. Because of these difficulties, WWVB) and the U.S. Navy (NBA, NPG, Here's your new catalog of quality elec- Marconi developed the magnetic de- NPM, NPN, and NSS) were retarded by tronic kits and assembled equipment 100 millisconds tector which eliminated the mechanical at zero hours Universal . your shopping guide for TV set kits, Time, on September 1, 1964. difficulties and the burn -out but left transistor radios, voltmeters, scopes, The adjustment became necessary be- tube testers, ham gear, PA systems, much to be desired as to sensitivity. The cause of changes in speed of rotation of and a host of other carefully engineered wireless receiver was the weak link in the earth as determined by astronomical products. Every item in the Conar cata- the system and Fleming was given the observation. Such adjustments are made log is backed by a no- loopholes, money- job of improving it. by international agreement, according to back guarantee. It's not the biggest In October 1904, while thinking about a plan whereby the times of emissions of catalog, but once you shop its pages this problem of wireless detection, Flem- time signals are synchronized to about 1 you'll agree it's among the best. For ing recalled the experiments with the millisecond. The last previous adjust- years of pleasurable performance, for ment in phase signal Edison-effect lamps and their ability to the of time pulses fun and pride in assembly, mail the was made on the first of April, 1964. rectify low- frequency currents. Would coupon. Discover why Conar, a division Countries participating in the coordi- of National Radio Institute, is just they rectify the high- frequency current nation are: Argentina, Australia, Canada, about the fastest growing name in encountered in wireless reception? Czechoslovakia, France, Italy, Japan, the kit and Concerning this last question Fleming South Africa, Switzerland, United King- wrote: "I asked my assistant, Mr. G. B. dom, and the U.S. CO1tLJR Dyke, to put up the arrangements for creating feeble high -frequency currents ---I MAIL NOW !1 - NMI in a circuit, and I took out of a cupboard one of my old experimental bulbs. The COHAR NB4C , experiment was at once a great success 3939 Wisconsin Avenue, Washington, D.C. 20016 , and I found I could use a galvanometer Please send me your new catalog. to detect feeble oscillations ... ". Name Fleming in this case had used the rec- Address , tified energy of the incoming signal as

City his sole source of power. No plate battery or other local source of power was used State - Z -code to augment the strength of the received 70 inT ----_-111111111111 signal. CIRCLE NO. 245 ON READER SERVICE PAGE 78 ELECTRONICS WORLD

www.americanradiohistory.com Additional information on the items covered in this section is available NEW PRODUCTS from the manufacturers. Each item is identified by a code number. To obtain further details. simply fill in gc LITERATURE the coupon appearing on page 15.

COMPONENTS TOOLS TEST EQUIPMENT HI -FI AUDIO CB HAM COMMUNICATIONS

MODULAR ROTARY SWITCHES \fa\iliollll current r:lUng is -1(1(1 amperes r.m.c. Item'}'. nrcdiunt, or light dust applitaitns.

1 Oak %lanml.uCuing Co. is unw ulleliu, ils or a half -w:nc anti-age toting of 10 :imputes. 1 he gum Icalurc. aulttolatic thermal regulation .. \Ioduline iotas sw its tchith will be 1oltcard blocking %ollagts limn -III is 1111111 Audis whit :11110111;11 il adjust, the heat petrel 111 Ille

:nailahlc in 2 million different ea'iatinus. ('sing arc asailalu e. right level Imr the ¡Oh. I he line point lip is for the modular principle. OI'. \I (ngintel' tan slue( il' use in the 25 tu 11th oat lange. Ille medium -41111%

i be 11111 111 _1111 w t one of 111.1 semi-( roslunl Stt iu lies [shit li can R.F. MILLIVOLTMETER PROBE tip is fur the :111 :ulge. %%hilt' the assembled and shipped sttcn da\s alter receipt of Porter Elec ironic' Laboratories has heats -dhls tip is for tun to l'un wart applitaliuns. the ou1ul. 1.1 a IleW and intpruccd probe for its li2li r.f. I he institiment Ineasulr,'t s'' long 21 _" t%idc l0 assist the engineer in specifting the switch. ntillittltntttcr. .I he %.sauts. is intprosed to less -`c" high. II has a 0 loos lime tord tut initiated Its .1 011 the tomtpals Iras de,eloped a unique catalogne than 1.2 to 2111111 nut. I-letinents ut( it a( s is 5, molded plug. It optl.tes 1211 %alts a.c. from III tu 211 kc..:t from 211 kc. lu 11111 eight of the gun is a. moues plu a ounces ter from IIIII to 31111 mt-.. 10'; I ?0111 all to 11111(1 mess I hr rond. and 211''; Rum 1111111 to 2111111 mt. I he 'Hobe has a nlasinnun input of "100 toits PHOTOCONDUCTIVE CELLS 111 tic cults a.c. (:tairez Corporal' iras anuo11nttd 1 nt-it, s .mailler. more r uggcd photo( multi( tits tr11 THIN -FILM RESISTORS nllulin, i',1 tu 2 watts o' poach dissipation. 1 he lletavac. Inc. is now offering a wide variety new -'\I sel its is olleted in eight lopes ut cad- 6 at cntl and disc thin-film resistors for appli- mium ''I I'hide and tadntiu11t scltnidc .ensuite cation in the inkuots:ist and oilier high-frequcncv mate' i,,l Ina hut mut nails sea jet( metal case only

fields. They crut be 11,111 :Is cua\ial l et na jutai ianc. .110 inn It iii 411 :1111cicl.

r.f. pacts. duntuts loads. Coupling loops. aucnu- 1 he units hate sollagc ratings tip tu .Inn tolls anus. and intpedame-ma !ling devices. and light resitance down to 2',11 ohms al 2 luul-

Mid use 1.1111. I t 1 imp Mans ings l cast Io oulrr mitt '1 -liese rtsislots Ile (lined in langes of 1 to atilt et 1,d es. ttte design ch:u:wel ist it s 01 are eliminated sinie ohms with potter Emin'. loon 1 s [sait lu I5 watts. a swiull designated by a series of eight tuna. :ti Precision utlmanti- grades ool u , and 2'; are DIFFERENTIAL VOLTMETER tshich are I10111 uhf bels (hi tligits1 selected taia- standard. Fe :inning as unusually low- icmpera- Hewlett- Packard C pane has rlamll' in- lugue and w glati un the orticr cacti. tnre coefficient. cvccllcnt talle stabiliis to 10 troduced the Model 711 Ilse. -tic. differential icalcul. pun ilion cumpunents, ('sing prcfabt tic 2151 (:., and hating the impel % of being nun suluneter /d.c. standard which combines sie func- can assemble susitthes fmllawing the de- p:a\ intluuive. these filet resistors are olltrtd unlit tions in a single. «impact solid state insu r omelet. sign configurations in lit:trd 011 the miner taud. sott -soldered limned eke rodes to Lie iIiLitt' all 1 he Model 711 -1 is a 41st. dillett.mial voltmeter cutventional (incuit subletie technique -. of 11.11; :' accuracy which mac. also be used di- TEMPERATURE CONTROLLER 2 liking Industries, Inc. is now offering the NARROW DECADE COUNTERS Model 4-4111 digital set tcmpeiatuuc conuul- tllcgan Instillment ( has .0:Iilahlc t(r ',Mill haunt' the i ipitut u lias of a digital a new series of narrai ,,Iode counters with M s% slum and the acunais amui stability of a prupur- pre -set capabilities Ior et :ut situp counting luit Im the ertmpant. iion.1i tonuul. utcortiing l' . l he Series FI I I units are available ttith 1-.74-171 I Ile ucuc 111 01 is ti rouit. of tnnnulling I"10 taunting rates of 2111) kt'.. I mc.. and 10 nn. stalls of I Ia'smlt, 611 %t le powcl. l Ile tnnu0ller is \toilets are :nailahlc in four tunligui aiow.. in atljuclbi( in I C. slops mum lia C to ' 2011 C clu41ing built -in single prt'set toc slat ut' stop 1.

I C :nad and han an absolute a« tom, 0f - scnsi- 'unctions alter a pt -set number tul pulses. and sass titil' ul ILI (:. 1 he unit Ine:nitts',I 1 "\ 1 "s final plc sel for t,mbin :uiun si:11 t MO cop. R-

I he units moult an 1 -inch ct'ntcrs. Iltcy are ree- dy as an cIectrunit' fisc. voltmeter: the input LABORATORY POTENTIOMETER tolnplctcic solid- state. emplo%ing silicon uamsis- impedance is constant and greater than 1111111 mcg. Trintpot Iliyfsfon of Bourn . Inc. has tictcl- tots in a Mouin:t, think 'tir (outing logic. ohms. regardless of null Condition. 3 aped a dialrea(Inut precision pattntiunretc'r Glass epos% circuit hua idc are used. with output .\s an a.c. measuring instillment. the unit in- designed espy(ially tot' laborauus applications. nodutes a churl capaen:line of less than 1 pf. at I he \lode' 11;00 "Labltut" is designed for rapid the "ouch and read" point in the measured cir- setting of pietist ttulclges. or reading of the re- tnit. 1 he sl resistance is I nugohln. : \. ai' quired \allagts to a( hie, e null in a bridge circuit a.c. dillmential toluneler. ils spccilicd :uuuau' applicuion. SinliLnl. it eta% be used for the in- is 11.1'7 of reading X11.111';, of full scale. from troduction of known uesistance %aloes in a eir- 11.1 volt to IIInul toits. tuil. \ built -iu rettntler output is driven by a (1.c. tshich he used sep:aael'. will' a 1 he standard model is available in Ihtee re- amplifier Ina, sistances 1111111). 10.01111 and 11111.111111 ohms, but masinnun gain of tin Ilb anti put of i %11l1 into 2111111 tut mlNils special %alucs col he supplied on t ttlut 4. ttl this 111111['. Rcsislaut hdclal(e is 1-I ó and resolution is 11.112S'; Im 0.010q. L.F. WAVE & SPECTRUM ANALYZER (luanTech Laltlralol it s, Inc. bas dcstlopcd HIGH -POWER SCR'S 11 a new tow lrequems and spctlrum an- \Vesting' .. Se !tartar Ditis' las .11,Ier which the tunlp.tn% (laines proeidts meas- cunntctiuns far lo -line coincidence. i -2.4 -8 hinar%, 4 inu'aduttd a new line of high power silicon ulrntcnl capabilities 11111 111aliv associated with staircase. : and puke output to duite other decades. tunuolletl 1ettilit'1s , 11'I)F(. _' \ :I:NI srliesl. I pese nnnh r elalimme and lull equipment. 1 he in. plane. segmented Pe unmet ical display des i(t-, Il' :tutu al 1.ldlt all\ Ilea tontrpt ilia power it l'stlll as a standard Igue anaivtr for har- is Yt" high. Bright. 11111.111111 -hum lite incandescent scmiunttluuor tlesi_ii. 1 hose uv hnitlnrs itut lulle monie and Iholtiet ,iuu;i Is sis of toupies Wa%e- the Ilse of compression boudiug t not psuLtiun lamps ale used for high tisiluilii, and wide -angle hums. the \Iode! all lias uhrte selectable flat s (C11F.1 and an integial hell sink design. 1 he CBE icwing. lopped bandtitllhs I. In. 1011 (Arles) that also cä11511 it ti) iiiulinales solder it tines In the Ilse make it ideal fut speMAI density' ataltsis of 111' high pressuni' 10111.11 1, 10 lut.tinlain eiet(Vit'al 25- TO 450 -WATT SOLDERING GUN randnml signals. I still tt 1111 a smite. \ -1- pluller. :11111 Olt lnl :d antaut heisren Ille SCR %%Act' and Kiln l'"udus, "1""s Inc. has dcteltp ih"'Ad"'Ad tir sui 11.111 tetrltdt't it N1'0111011 a splcrtunl the ba,u. I Ili' ttnsuutlion is completely lice 8 Mall ".111" soldering gent whir makes possible :Il1a1%/el of 11 ide pt-1101 :nu'c Ch:r:cillislit5. mom i ltttuai latigue. I he integral heat sink heat colonic ranges Rom _"I to 1-d0 ;11 Is in one Il'equrnl\ Iallgt is I e\( le In 5111)0 (Nell, ti'ilh

111 cl im Mat s Ihr 1 ant lo sink I hot utial impedance small. lightweight gun. Its (hanging lips. which an a11 111a1s al 1'; ont 1 %Cll. :11111 i 11%nanli( Innnil in comcsiliun:d semiconductors. can he done in seconds. the gun is read for sttrsili %ity of Iront ;u t. Io !nn t. full scale. December, 1964 79

www.americanradiohistory.com Typical applications include use in vibration Applications for this new 100 -mc. plug -in in- DO YOU SAVE YOUR COPIES OF analysis, geophysical measurements, medical, clude radar and computer analysis, semiconduc- oceanography as well as general spectrum and tor studies, and pulse analysis among other of wave analysis. the advancing technologies.

u Electro ics World MINIATURE ELECTRIC DRILL HEAVY -DUTY RELAYS Jensen Tools has introduced a tiny, battery 17 Milwaukee Relays is now offering the new 12 powered drill which has been designed for "900" series relays for heavy -duty applica- many types of light-duty drilling and grinding. tions in motor control, elevator control, heater The Model 9 accommodates drills up to 1/2" loads, welder controls, and other power switch- diameter. Although designed primarily for light - ing applications. duty drilling of aluminum, plastics, gold, silver, The 900 is a 10 -ounce relay with a maximum and platinum, it is capable of chilling through coil resistance of 64.000 ohms and a contact rat- Vi" solid brass. Starting torque exceeds 5 -inch- ing of 25 amps at 115 volts a.c. non -inductive or ounces at 6 volts. 1 h.p, at 115/230 volts a.c., single- phase. The drill operates from any d.c. source from 4 Coil terminal breakage had been eliminated by to 12 volts, depending on the power required. having the coil terminal terminate on the base

Normal operating current is less than 1 amp at which acts as a back -up support. Electrical shock 6 volts. The motor is "TV" suppressed. hazards are reduced by maintaining the position Make sure they're kept neat and always of the flexible lead conductor with a guide built handy for instant reference -with a hand- MICROPHOTOMETER into the armature. Heat dissipation and long 19 Grace Electronics, Inc. is currently market- life are assured by extra heavy stationary con- some file that's designed to hold a full ing a d.c. microphotometcr, Model 380, for tacts. year's copies! making micro- uricrolumen light measurements Engineering sheet 51F649 provides full details with exceptionally short rise time and high sta- on the "900" series. bility. A variety of is washable Kivar cover has a leather- detachable probes available including visible, infrared, and ultraviolet, all of DIGITAL DEVIATION OHMMETER like appearance which use multiplier phototubes as transducers. 10 Non-Linear Systems, Inc. is now marketing

Rise time is 0.5 msec. on most ranges and 1 10 he Model 2033 digital deviation ohmmeter available in maroon backing with black msec. on the 1 millimicroampere range. Seven which automatically treasures resistance directly in terms of percent deviation from some stand- sides or black with maroon ard resistance value, or alternatively, absolute resistance values. 24 -karat solid gold leaf embossed letter- The unit is useful in resistor or integrated circuit studies, ing for magazine's name production, reliability research, quality control, and environmental testing. In automatic systems applications, its direct readout of attractively priced at only $2.95 each, 3 percent deviation eliminates expensive digital for $8.00, 6 for $15.00 arithmetic computation equipment. Specifications include direct readout in percent deviation from +99.99% to -99.99% in steps files are shipped to you prepaid and are of 0.01%, automatic polarity indication, wide fully guaranteed styitchable low-pass filters are incorporated to range of 10 ohms to 10 megohnrs, high over -all permit reducing the speed if fast rise time is not accuracy of ±0.05 %, and a high measurement desired. speed of 330 msec. per reading. NOTE: these special -quantity prices apply for The unit is permanently calibrated in micro- any combination of titles, so you can have them amperes within 1.5% and has nine ranges from BINARY DECODING READOUT for all your favorite magazines. -5 10 ampere to 10 ampere. A 6-inch ureter and Cal -(ao Coutpauy has mailable a projection - Order several today -for all the Ziff -Davis mag- a 3 -ma. recorder jack are the outputs. The d.c. 19 type, binary -to- decimal readout. employing the 8 -4 -2 -I code, azines: Popular Photography, Modern Bride, HiFi/ amplifier drift is less than 2% in four days. standard binary known as the "Shelly" IIDR -100 readout. Stereo Review, Electronics World, Popular Elec- The unit is designed especially for readout ap- tronics, Flying, Car and Driver, Popular Boating, U.H.F. CONVERTER Gavin Instruments, Inc. is now marketing a plications which require a binary -to- message con- Amazing, Fantastic, and and for your other favor- 14 deluxe model u.h.f. converter which has version such as computers, counters, and other ite publications, as well. (Ziff -Davis magazine files been tradenamed "Venus." electronic and electrical equipment. It will accept available in colors of your choice as noted in cou- The new unit features a high built -in ampli- pon. Those for other publications will be shipped fier and special solid -state circuitry for peak all - in standard colors available.) channel reception, even in problem areas. The converter has a special fine -tuning control for r smooth. simple operation. Jesse Jones Box Corp., Dept. EW Box 5120 The converter is housed in a decorator cabinet Philadelphia 41, Pa. in soft gold with tawny brown accent.

Please send me: (Fill in title, quantity and SCHEMATIC MARKING SET ig The Datak Corporation is now offering "in- check appropriate column for color desired) stant lettering," a dry transfer electronic schematic drafting material. Each kit contains BLACK MAROON BACKING/ BACKING/ sheets of all the commonly used schematic sym- MAGAZINE MAROON BLACK bols. Line widths and symbol sizes have been de- TITLE QUANTITY SIDES SIDES signed to fit in with standard industrial and mili- four -line parallel binary coded decimal informa- tary drawing procedures. tion, decodes it into twelve messages, and dis- Electronics A new adhesive, especially compounded for the plays the desired message on the front viewing World kit, adheres well to all tracing papers, vellums, screen in clear, distinct characters. and Molar sheets. The transferred symbols will The circuit contains no moving parts and fea- not rub off its normal handling. In use, a ball- tures silicon semiconductors for reliable opera- point pen rubbed over the symbol releases it from tion over extreme temperature ranges. The read- the carrier sheet and adheres to the working sur- out weighs less than 3 ounces. $2.95 each, 3 for $8.00 or 6 for $15.00 - face. shipped prepaid - fully guaranteed SUB -NANOSECOND PULSER OSCILLOSCOPE PLUG -IN General Applied Science Laboratories, Inc. Fairchild Carrera and Insu- nt Corpora- 20 has available a new sub -nanosecond pulser Total amount enclosed l') tion's Scientific Instrument Dept. has devel- which provides 2 amps of current into 50 ohms oped a new plug -in that permits a standard high - with less than 0.3 msec. rise time. Designated the Name frequency oscilloscope to handle signals of 100 Model 2303, this compact. remotely programma- nu. with a pulse rise time of 3.3 nanoseconds. ble pulser is useful in checking semiconductors, Address Designated the Type 79 -02A. the new unit will switching circuits, magnetic devices. and in nu- fit all Fairchild 765 and 765H series oscilloscopes. clear applications cohere precise amplitude con- City Zone State It features dual -trace performance with IO mv./ trol is necessary. cm. sensitivity. The instrument employs a mercury -wetted, L 80 ELECTRONICS WORLD

www.americanradiohistory.com long -life switch in a specially designed coaxial servo amplifiers having single- ended inputs. Both bound into a bard -cover looseleaf binder. Con- cavity, providing reliable operation almost in- electrical and mechanical damping are used for tents are alphabetically arranged and each sheet definitely. A unit tuning control on the mercury optimum performance. is numbered for quick reference. switch cavity provides slight adjustment of the Any desired single input span from 100 niv. leading edge overshoot. full scale to 1110 colts full scale. each axis, is avail- PC TRIMMING POTS able although 1 -v. full scale is standard. Accuracy Clarostat yIfg. Cn., Inc. is now offering its 63xl ri;Al BIDIRECTIONAL COUNTER is 0.1 percent full stale. 26 Series -I :uul -2 trimming Puts which Anadex Instruments Inc. has announced the Lhe unit measures 101/2" x 13" x 41/2" and have been speeificallt designed for application on 21 availability of a solid -state, bidirectional weighs about 10 pounds, printed- circuit boards. When seated on a PC card, electronic counter featuring an internal power over -all height is l'í ", permitting extremely supply for powering remote pickup heads. DISPLAY STORAGE TUBE close board -to -board ,spacing. The Model CF -4008 is capable of accepting 'Westinghouse Electrotik Tube Division is Electrical specifications include a .25 -watt dis- add /subtract information from two different 24 now offering a high-resolution, rugged-con- sipation rating at 70 C ;Ind metal -to -metal and on] cuts, Flinn the same source on separate lines, struction display storage tube. the type AV X -5047, carbon- to-carbon contacts to provide higher reli- which gives air-to-air radar an air -to- ground ability. extended life. and extremely low noise. capability. \lotrnting terminals are gold plated and located The tube is designed for use in systems that re- for 0.1" grid configuration per industry standards. quire controllable persistence. signal integration, Mechanical and electrical rotation is 295 ( +3 ), or Flom quadrat re signals. It is .0tidablc utitlr high writing speed, or display brightness greater Units are available in a resistance range from 1 is -1, 5, or tì wide -angle "Nixie" displays plus polar- than that available Iron cmsentional CRT's. 100 ohms to ntegohut. Working voltage 350 ity sign. At a writing speed of 100.000 inches per second, volts a.c. between end terminals. The counter measures 1.3/4" h. x 13" d. x 19" w. the tube has stored resolution of 9)) lines per inch Power requirements are 105 -123 v. r.m.s., 50 to 60 when saturated brightness is 10'7- as measured by SOLID TANTALUM CAPACITOR cps. 25 watts. the shrinking raster method. Minimum saturation Cornell- Dubilier Electronics l)is¡slot] has an- brightness is 12)11) footlautbcits. The tube is elec- 21 nounced the ;mailability of a new dipped focused and deflected and has a single MOTOR -SPEED CONTROL trostatically solid tantalum capacitor. Type i I)R. \l odulouics Inc. is now offering "Select -A- writing gun. Oser -all length is 14vá ", usable di- The capacitor combines the advantages of high - 22 Speed," a low -cost version of its industrial ameter is 4 ". density packaging, radial leads for direct place- controllers. This unit provides motor -speed con- ment in PC boards. high solunnetrie efficiency. a tiol through a full range, from top speed to "al- ELECTRONIC MARKING KIT broad range of ratings (from .47 µf. to 330 µf.), most slopped" without loss of torque, eliminating Chart -Pak, Inc. is now offering an electronic maxintunt en%ironntcntal protection, and dual danger to tool or control unit. 25 marking kit for engineers, draftsmen. and operating temperature ranges: -55 -C to -55° The best cutting speed is dialed by means of a product designers in the electronic and electrical without t tlttge dcration, or -125 -C with speci- front -panel control. Powered by Ill -volt a.c., the industries. fied voltage deration. control delivers a full 700 watts of continuous Hundreds of frequently mused titles. words, on power to the tool. codes. letters, and numerals are preprinted HI -FI AUDIO PRODUCTS dry transfer sheets to facilitate labeling and mark- - COMPACT X -Y RECORDER ing on control panels, drawings and schematics, AM /FM- STEREO TUNER F. L. Moseley Co. has announced a new low - printed -circuit terminal boards, and electrical and Lafayette Radio Electronics Corporation is 23 cost, ultra-compact basic systems X -Y re- mechanical components. 28 now uiiickeling a new AM /F \I- stereo tuner corder, the Model 7050A. The kit. which is offered in black, white, red, or as the Model LT -325. The new unit is adaptable to almost any sys- blue, contains thirty 3 "x Ii" sheets, each with a l'he unit features a "Stereo Search" circuit tem requiring high -accuracy X- t' readout at mini- separate backing sheet that is chemically treated Which produces :ut audible signal in both chan - mum cost. It features all solid -state circuitry with to prevent accidental transfer.. : \II sheets are ncls when a stereo station is tuned in. l un er

Everything you ever wanted in a CB transceiver! Back Issues Available Use this coupon to order back issues of ELECTRONICS WORLD We have a limited supply of back issues that can be ordered on a first -come, first -served basis. Just fill in the coupon below, en- Newest! Most Versatile! Most Power Out!

close your remittance in the The I I channel "Messenger I I I" will change every idea you ever had about what a Citizens Band unit should offer! Tiny, all amount of 65 each and mail. transistor, it's really quiet, really hot! Interchangeable for base or mobile -use it as a full 5 -watt battery powered portable pack (Issues prior to 1963 set or a 3 -watt PA system. The "Messenger III ", with an aero- not available.) space transistor developed for the "Relay" communications satellite, delivers more power output with maximum legal input! Double conversion receiver with high Ist I.F. ZIFF -DAVIS SERVICE DIVISION provides excellent spurious and image rejection. Set - Dept. BCEW, 589 Broadway and- forget "Volume" and "Squelch" controls make it possible for the first time to work "close -in" or New York 12, New York at extended range with initial settings. Furnished Please send the following back issues of ELEC- with dynamic microphone -full line of acces-

TRONICS WORLD. I am enclosing to cover sortes available for selective calling, portable the cost of the magazine, shipping and handling, field pack, or public address use Cat. No. $189.95 Net Month Year 242 -150 Month _ Year 1 _ Month _ Year _ E. F..lf]H1iti0N C[l!lil'AtiY Name ® i 110 i, -nth Ave. S.Vd. PJnseca, r.Lnnesota Please send full details on the "Messenger" CB line. WRITE TODAY Address for details on the NAME "Messenger" CB City _ _ Zone line -or see your ADDRESS -State e t st n bu tor! EW No charge or C.O.D. orders please. Clry ',TATE CIRCLE NO. 191 ON READER SERVICE PAGE December, 1964 81

www.americanradiohistory.com lighted push -button "on -off" switch, separate channel treble and bass, program selector, vol - ume, speaker-system selector, speaker balance control, and headphone jack. The SR900 measures 1614" wide x 5" high x Ils/n" deep. The walnut enclosure is optional equipment.

WIDE -RANGE SPEAKER SYSTEM Neshaminy Electronic Corp. has introduced sensitivity is 2 Av. for 20 db signal -to -noise ratio. 32 a new wide -range speaker system for stereo Frequency response is from 15 to 15,000 cps and mono hi -fi applications. ±1 db and channel separation is better than Known as the Z -700, the new speaker features :18 db tê 400 cps. The unit incorporates a variable a pair of "iansZen" 130 push -pull electrostatic If you've recently changed your address or a.f.c. and multiplex noise filter. A built -in ferrite radiators which reproduce middle and tipper frequencies with unmeasurable plan to in the near future, be sure to notify loop antenna is used for AM reception and a distortion to 30,000 300 -ohm antenna input is provided for FM re- cps. Bass is reproduced by the Model 350C dy- us at once. Place magazine address label ception. namic woofer. The woofer has been specifically designed to function in small, totally enclosed here and print your new address below. The instrument is housed in a dark beige cabinet which measures I4s/a" wide x 53z6" high x cabinets. Its heavily weighted, high- compliance 91/2" with legs. cone is capable of Mt" excursions without break- NEW ADDRESS: up or doubling, down to all cps. "CONFERENCE" RECORDER The totally enclosed, fiberglass -filled cabinet NAME Stenotape I)iv. of American Geloso Elec- is finished on all four sides. It measures 15" h. x PLEASE PRINT 29 tronics, Inc. has recently introduced a fully 26" w. x 131" d. and is available in either lac - transistorized portable tape recorder designed quered or oiled tsalnut cabinet finishes. ADDRESS especially for dictation and transcription and conference applications. TRACKING -ERROR INDICATOR CITY ZONE STATE The 4 -10 is a 3 -speed machine that will operate Alard Products has developed a device which for 10 hours from one patented self- loading reel 33 indicates visually the amount of tracking er- MAIL COPIES TO NEW ADDRESS STARTING of tape. It conies complete with a remote-control ror in record players and positions the tonearm for optimum performance. WITH ISSUE. hand microphone. The unit has a digital counter for easy spot Tradenamed "Tru- Trak." the unit consists of If you have any questions about reference, a built -in handle for portability, vu a pointer assembly that attaches to the cartridge your subscription be sure to include meter, anti built -in clear plastic dust cover and and a calibrated scale that fits over the turntable your magazine address label when latch. The machine will operate with the dust spindle. As the tonearm is moved across the turn- writing us. cover closed. Available accessories include a foot pedal and finger -tip control, conference micro- Mail to: ELECTRONICS WORLD, phones, telephone pickups, earphones and head- 1255 Portland Place, Boulder, sets, mixers, and a 12 -volt auto adapter. Colorado 80301 FM- STEREO CAR RADIO Delco Radio Division has developed a tran- 30 sisim-ized stereo adapter which is designed to be plugged into the 1965 Chevrolet AM -FM radios with no modification of the radio receiver. Your Postmaster Suggests: It will be offered as a factory option or can be installed later by the dealer. "Belair," and "Biscayne" mod- Always Include The "Impala,'' els use foin- speakers for stereo reception. The two front speakers are located under the instru- Your (ZIP CODE) Number ment panel in the cowl kickpads and the two rear seat speakers aie mounted at the outboard in your ends of the package shelf just behind the back seat. The adapter is fully transistorized. containing Return Address 11 silicon transistors. one germanium power transistor, and six diodes. The audio amplifier table, the pointer indicates the tracking varia- for the additional stereo channel is contained tions of the tonearm. By changing the mounting within the adapter unit. Automatic switching position of the tonearm, an increase or decrease in tracking error is readily apparent. Egee to receive both mono and stereo programs is EARN DEGREE provided. :An indicator light shows when a pro- The device is matte from Lucite and fits stand- You c an A..s.r;.r:, degree at home. College level I ltti Cll.rtL4T11l)r eht under. gram is being received in stereo. ard cartridge mountings. ml Ihe,n. ontim«,n. edud arson. > the! highly paid eledardr ru nhtI.lTy. Dit silo no lnoel.. t1,111,í tors. lutiun. replete electronics. Over 27.0110 graduates- employed. Resident TRANSISTORIZED STEREO RECEIVER NEW SPEAKER DESIGN school available at Crir',g c.nnpus- 3rouod cri Utah Electronics has just introduced a new 11) :34. Send for free catalog. Il:rntan- Kardon is now offering a new all- speaker which features roll suspension American Institute of Engineering & Technology 31 transistor series of FM-stereo receivers which 34 cloth 1141 West Fullerton Parkway, Chicago 14, III. includes the Models S12900, SRb00, ;sill SR300. for smoother bass response and dual cones for Designated as the "Stratophonic' tins. the reproduction to 2)).0011 cps. P. I(, - features embossed .1í2!l11[) is the top of t he line. It Ii rLIue, IIIl The \f \ \'CR trans- LOW -COST BUSINESS AIDS former mounting facilities (for transformers up FOR RADIO -TV SERVICE to 21.-k" mutmtiug centers). shallots' construction Order books, invoice forms, job ticket (only 3" deep), internal dust cap for positive pro- books, service call books, cash books and tection of the close -tolerance voice -coil gap, and statement books for use with your rub- screw terminals. ber stamp. Customer file systems, book- keeping systems, many others. Write for Specifications include a 10 -oz. barium ferrite FREE 32 PAGE CATALOG now. magnet, a I" voice coil. it peak power rating of OELRICH PUBLICATIONS 3)) watts, and frequency response 30- 20,0110 cps. 6556 Higgins Rd., Chicago, III. 60656

music power output of 75 watts (37.5 watts per FM- STEREO RECEIVER channel) at 4 ohms; frequency response 2 to Bogen Communications Division is now mar- a (30 INSTANTS PARK 100,000 cps ± 1 db at 1 watt and 5 to 60.000 35 keting the RT6000, 60 -watt watts QUALITY TRANSISTORIZED IGNITION MADE BY cps at full rated power. Harmonic distortion is per channel IHF music) solid -state FM- stereo re- NATIONALLY- ADVERTISED MANUFACTURER Dependable-Guaranteed $16.95 Postpaid less than 0.2% and hum and noise suppression ceiver. Pays for itself High-Quality transistors is 95 multiplex separation is 40 db. The FM section has a sensitivity of 2 Av. for 20 10- minute installation Full z r protection db. The All U.S. components Completely epoxy-sealed convenient fingertip db of quieting at 3011 ohms and distortion of less Similar units sell for $29.95 or more. The receiver features Fits all 6V and 12V negative -ground systems. Parts switches for contour, tape monitor, hi and than 0.5% at l))O - modulation. Stereo separation and circuits available. Send for list. rocker Send check o money order to: lo cut, tone -control defeat, and FM interchannel is measured as 25 db at 50 cps, 35 db at 1000 cps, Pp. Baps 51a INSTANTSPARK, r Shermn Oak s. Caliafornia muting. Other front -panel controls include and 20 db at 111,1)00 cps. Response is ± 1 db from

82 ELECTRONICS WORLD

www.americanradiohistory.com switch and front -panel 15 to 50.000 cps. Noise and hum level is rated at SOLID -STATE INTERCOM LINE speaker headphone outlet -65 db. Rauland -Borg Corporation has just intro- for private listening with the speakers silenced, The receiver has a brushed gold front panel 31 duced a new solid -state, all- transistor inter- a powered center -channel output for an exten- which features simplified cont oil: and tuning com line, the "Amplirall" 740I) series. sion or center -channel speaker without any addi- meter for precise program selection. Provision is The new line offers a wide variety of flexible tional amplifiers, and heavy-duty output trans- made for phono, tape head, tape monitor, or aux- formers for good bass response even with in- iliary inputs. Outputs include speakers, tape, or efficient speaker systems. headphones. A stereo minder indicator automatically CB- HAM -COMMUNICATIONS switches from mono to stereo when the station broadcasts in stereo and indicates the change visually. The unit measures 16" wide x 14" deep x LIMITER -AMPLIFIER 4%s" high (including knobs). Kahn Research Laboratories, Inc. has devel- 39 oped a new, low -cost limiter -amplifier which meets or betters FAA operational specification INTEGRATED STEREO AMPLIFIER R543 -D. Whitecrest Industries, Inc. is now offering The Model LIM -63 -1A utilizes two compactrons 36 an integrated stereo control amplifier which and one rugged octal tube. It features a fast provides 100 watts peak porter output (both attack time. The instrument covers a range of and 60 watts music power output (IHF, channels) systems permitting communication with up to 18 300 to 3000 cps and meters compression and out- both channels). remote points. The circuit features instant opera- put level. Precision step altenuators on both the Frequency response is 10- 20,000 cps ±1 db tion and virtually no heat. The intercom is ac- input and output circuits are included. Input and sensitivity (for rated output) is 300 mv. tivated by a "talk -listen" bar and features an ad- and output impedances are 600 solins with a 25- (high -level inputs), 3.5 mv. (phono), and 2 mv. justable volume level. There is a central power ohm microphone input provided. supply for the system with plug-ill junction The omit requires 31/2" of standard 19" rack boxes. space. The intercoms are housed in ultra -modern en- whirls are acoustically treated. Three closures PLUG -IN R.F. TUNING UNIT types of remote stations and complete accessory Defense Electronics, Inc. is now offering a equipment are available. 40 new plug -in r.f. tuning unit, Model TM1-1- S5B, with a tuning 66 -WATT STEREO AMPLIFIER range of 250 -500 mc. 1-1. H. Scott, Inc. has added the Model 233, and has a.f.c. applied o a 6b- watt stereo amplifier to its line of com- 38 to the second local os- ponent loi -fi equipment. cillator in either v.f.o. The amplifier features new decorator styling, or crystal -controlled (tape). Output impedances arc 4, 8, and 16 ohms. tootle. Each channel has individual bass and treble Designed for use controls. A separate loudness contour control pro- with the modular vides the proper compensation for low -level lis- TMR -5A telemetry re- tening. ceiver, the compact The chassis measures 53/4" h. x IS" w. x 91/2" d. unit covers both A grained oiled -walnut cabinet is available at standard U.S. and European telemetry bands. additional Cost. When used with the TS1H -B5 tuning unit, con- MONEY- MAKING OPPORTUNITY WITH A NEW TYPE OF BUSINESS

NOW . . NuTone, America's largest manu- In Home Entertainment Systems . . you can facturer of Built -In Music Systems .. offers supply an even larger market through the you a fine opportunity to own and operate a existing homes in your area. profitable business in your locality. Home owners are surprised at the moderate You can start in full or spare time without cost . . and are pleased to learn that they can previous experience. You need not worry about have a complete music and intercom system large inventory stocks . . because NuTone's installed in the homes they now own. network of wholesalers can furnish everything You can start this business at a minimum in- you need at extra special discounts available vestment . . and expand it to a large staff of to you. sales and installation specialists. We offer you The modernization market is booming . . and complete details . . just mail coupon to . . Built -In Music Systems are in big demand. Mr. Dickinson, Product Manager, Electronics Thousands of new homes have NuTone Built- Division, NuTone, Inc., Cincinnati 27, Ohio. BUILT -IN MUSIC and INTERCOM INSIDE and OUTSIDE the HOME! FREE FACTS COUPON INTERCOM -RADIO BUSINESS

NAME ' ADDRESS I/ Y CITY STATE I I YOU CAN BE FIRST TO START THIS BUSINESS IN YOUR COMMUNITY December, 1964 CIRCLE NO. 258 ON READER SERVICE PAGE 83

www.americanradiohistory.com ti nuotts frequency coverage from 55 to 500 me. radar installation on an exposed flying bridge or is provided. in an open cockpit. Front -panel switching allows the a.f.c., applied The Mould AIR -4\\' is available in either Di- to the second local oscillator. to he used with or 32 -mile ranges, operating from I2, 32, 1 II) volts either a standard or narrow -band FM demodula- d.c. or 115 -volt a.c. electric systems. tor. No a.f.c. setup adjustments are required Power line connections from the below decks with this unit. installed transmitter- receiver unit to the console Featuring automatic frequency control, the are through watertight stuffing glands. The slot- new unit has stability of -0.005% crystal con- ted waveguide antenna, transtnitter-recciser unit. trolled and approximately 0.001 %`C in continu- and power supply are identical to the firm's \Ili -4 ou, mode in the 260 -4110 mc. range. .Spurious radars. response is more than 60 db below fundamental The console case. chassis, and controls are es- ftequency response. Noise figure is 10 db maxi- pecially ruggedizcd to withstand exposure to the mum, 9 db nominal. elements and rough service.

IGNITION NOISE SUPPRESSOR RCA Mobile Communications Department MANUFACTURERS' LITERATURE 41 has introduced a transistorized universal noise clipper that can be used with a 50-me. two - stay radio to suppress ignition and other impulse CONNECTOR CHART Deutsch Electronic Components Division is noises at mobile or base stations. 44 offering a wall chart for determining specifi- According to the company, the plug -in unit cations on the company's line of D \I, 1)5. AIDS, operates effectively with any 50 -me. receiver ir- DD, MDR, DA, DTK, RTK, and hermetic connectors. Information is given on connector shell sizes from 3 to 61 with applicable contact patterns. The chart includes data on contact current rating, coupling mechanism air leakage, tempera- MODEL 55724 ture, and standard finishes.

NEW SOLID STATE TEST EQUIPMENT Simpson Electric Company's bulletin No. 45 41166 contains 16 pages of specifications and Crown RECORDER prices on the firm's complete line of test equipment for electronic, electrical, and temperature - THAT'S PRICED work. Listings include volt- ohm- milliammeters, v.o.m. adapters, hand -sized testers, scopes, and acces- AT ONLY $895 sories. respective of age, make, or model and automatically screens out ignition noise from its own IRON CORE COMPONENTS COMPARE PERFORMANCE vehicle as well as those nearby. United Transformer Corporation announces The clipper requires no modification of re- 46 the release of two new catalogues on iron core ceiver circuits and is inserted in series with the components. Volume I (32 pages) rovers trans- QuarterTrack Record /Play Data antenna connection to the receiver. It measures formers, inductors, and ntagantpss; Volume 11 ips db cps s/n 101/2" x 3" x 4" and may be mounted externally (24 pages) features electric wave filters and high with mobile and desk units or in a rack. "0" coils. 71/2 ±2 50- 25,000 54db Also included in each catalogue is a cross index 33/4 +2 50- 15,000 45db COMMUNICATIONS RECEIVER for locating desired components for a given ap- I Ianunarluud Alanufac tuning Company is plication and an explanation of sIIL specs. 17/8 3 30 10,000 45db - 42 now offering the Model 11Q -88 "drift free" receiver for operation on all the popular amateur ELECTRONICS CATALOGUE bands (Iu through 160 meters) as well as MARS, Lafayette Radio Elecunuits Corp. has an- COMPARE VERSATILITY CB, \V \V V, and marine band. According to the 41 nounced publication of it, I!0i3 electronics company, the crystal front -end design reduces catalogue for lotisse, industrt. ::rad laboratory. thermal drift after a short warm -up to no more The 511i-page listing includes hi -fi and tape rc- Incorporates the Crown use - tested than 50 cycles. coviing equipment. component parts. and test solid state control center, featuring The unit features highly selective circuits with instruments and gives specifications and prices for plug -in circuitry modules for quick skirt ratios of better than 3 to I, and separate the products of over 200 manufacturers. adaptation to a variety of specific AVI and SSB detectors. Sensitivity is a measurable tif. for a .A31 uses in home, commercial and labo- 0.75 I(I db signal -to -noise ratio, and POWER SUPPLIES better than 0.4 µf. for SSB and c.w. Aerate Electric Corporation describes the per - ratory recording.Audio circuitry, _1/4 48 t,rmance features of 36 standard. tegolatc l db from 10- 100,000 cps. Third head RADAR VIEWING CONSOLE d.c. power supplies in a new catalogue just issued. permits playback while recording. Bentl ix Marine has developed a completely '1-he 4 -page listing (175 -BAI2) is illusuaied and Complete pushbutton control. And, 43 waterproof radar viewing console especially gives mechanical as well as electrical character- i pleasure and commercial craft requiring a many other features. istics of the devices.

R.F. SHIELDING PRODUCTS THE HALLMARK INVEST Emerson & Cunning, Inc. is making available OF CROWN - 49 a new I -page pamphlet describing its line of SUPERLATIVE "F.ccoshicld" products. Alaterials cnveied include IN CROWN surface coatings, adhesive, caulking compounds, QUALITY CRAFTSMANSHIP and lubri,ann. THROUGHOUT! References :nr provided to technical bulletins where these :u, available. INDIVIDUAL PERFORMANCE PROPERTIES OF GLASSY MATERIALS RECORD SUPPLIED Corning Glass Works, Electronic Products Di- WITH EACH CROWN 5 n vision is one rn, a revised edition of its reference booklet on the various properties of materials. .Aimed at designers, engineers. and WRITE DEPT. EW -12 other technical personnel. the brochure prnvidrs data on electrical. thermal. chemical, optical. and mechanical characteristics, including volume resistivity. dielectric constant. thermal cuudnc- I N T E R N A T I O N A L tivity. chemical durability. luminescence. and 1718 Mishawaka Rd. Elkhart, Ind. photo- scnsitis its-. arnong others. In addition, the 8 -page booklet contains an ap- CIRCLE NO. 174 ON READER SERVICE PAGE 84 ELECTRONICS WORLD

www.americanradiohistory.com pendix of less familiar definitions and a chart which shows the electromagnetic spectrum.

R.F. COAXIAL FILTERS Bird Electronic Corporation has published a 51 10 -page illustrated brochure listing 80 representative r.f. coaxial low-pass, bandpass, and high -pass models with cut -off frequencies from 30 to 2700 mc. 1111011111 Typical performance curves and electrical and 111111110111...- mechanical data are given. ..

COMPONENT CATALOGUE qttt,t111i1I111;11111111111111111qIIIIIIIIl1111111111;.. U.S. Sentcor, the solid -state division of Nu- 52 clear Corporation of America, is currently distributing a new short -form catalogue covering its line of zener diodes, temperature -compensated reference elements, tantalum capacitors, and other devices.

PIEZOELECTRIC CERAMIC FILTERS Clevite Corporation's Piezoelectric Division is 53 making available a technical paper which presents characteristics of piezoelectric ceramic ladder filters and their application to electronic circuits. A general treatment of ceramic properties and basic filter elements is included, along with 20 line drawings. AWn Al rtcg,isan ele tronic or annaturall y. It 's not nece s sary to a genius eith.er e'l admit it's just difficullt enough to be a challenge. Therebe 's transistorized SCREWDRIVER SPECS circuitry in your favor with Artisan, plus simplified instructions. What do you have CA Xcelitc Incorporated has issued a new cata- when you finish? An instrument we modestly call magnificent, with the near- logue sheet (N764) containing a photo and est thing to the tonal qualities of a pipe organ. Right in your own home. description of a compact "Allen" hex -type screw- BUILD What about price? You'll keep 50% of the cost of a ready -built organ. driver set designed to simplify work on products And you may buy a module at a time , literally " play as you with "Allen" hex recess -set screws and cap screws. pay ". Get the complete Artisan story now. W rite Dept,. EW. Specifications for the screwdriver handle, in- A WHAT? terchangeable blades, and extension shaft are given. a division of Electronic Organ Arts, Inc. ELECTRONIC KITS 2476 North Lake Avenue /Altadena, California Heath Company, a subsidiary of Daystrom, 55 has just announced the availability of its 1965 "Heathkit" catalogue, covering over 250 elec- CIRCLE NO. 156 ON READER SERVICE PAGE tronic kits. The I08 -page booklet, with 16 color pages, offers a complete line of products in the stereo /hi -fi components area, ham and CB communications field, and electronic service equipment area. With this catalogue, the company is introducing many new products, including an electronic organ and a color -TV receiver.

ELECTRONICS CATALOGUE Allied Radio Corporation is now distributing 56 its I965 catalogue presenting the latest in hi -fi components, CB and ham -radio units, recorders and accessories, test equipment, radios and phonographs, tubes, parts, tools, and technical books. The 4- color, 490 -page listing also includes over FREE 100 items from the company's "Knight -Kit" line. BOOKLET TELLS YOU TANTALUM CAPACITORS Cornell -Dubilier Electronics has just released HOW 51 a 4 -page brochure covering the company's line of tantalum capacitors which exceed military specifications. The bulletin (21)8.1)0) contains pho- A proven formula for success is to get in on tographs and a cross -reference to competitive the ground floor of a booming business. Mobile types and military styles including tantalum radio is a booming business. All around, you can -way mobile -radio antenna towers foils, wet anode, and solid annule types. see two springing up -each one a possible new client for you, Most of this work is done on a con- HAM /CB CATALOGUE tract basis with payment 12 months a year. CO World Radio Laboratories has just published 'fhere's little competition . . few fussy cus- l its Catalog No. 24. containing specifications tomers to satisfy . a welcome change and prices on ham and CB gear and accessories. from AM /FM and TV repair! It's not too late Illustrated with charts and photographs, the 81- to make a start toward bigger money! page catalogue also includes sections on hi -fi MAIL COUPON TODAY( equipment and various component parts. Lampkln 105 -B Type 205 -A FM Frequency Me- Modulation Me -.. ter, 0.1 to 175 ter. Range 25 to I LAMPKIN LABORATORIES, INC. MC and up. Price 500 MC. Price MFM Division, Bradenton, (Florida COLOR -TV COMPONENTS $260.00, net. $270.00, net. Triad Distributor Division of Litton Indus- At no obligation to me, please send free 59 tries has issued a 10 -page replacement guide THE PPM METER -AN FOR booklet and information on Lampkin THE TYPE 105 -B. ACCURACY 0.0001 /o -FOR for meters. color -TV components for the receivers of SPLIT- CHANNEL FREQUENCY CHECKS 21 U.S. manufacturers. 50 MC.C. PRICE, $t47 00. I Name The brochure lists the proper replacement flyback, yoke, vertical output and power trans- LAMPKIN MFM DIVISION Address formers, and chokes for more than 1200 indi- BRADENTON, FLA. 1 LABORATORIES, INC. City - State sidual color -TV sets. J December, 1964 CIRCLE NO. 128 ON READER SERVICE PAGE 85

www.americanradiohistory.com 1964 INDEX

As a service to our readers we VOLUMES are again presenting a com- Solve Electronics plete listing of all feature articles which appeared in Problems Fast ELECTRONICS WORLD during 1964. We suggest you keep With Special 11 -12 this for reference. New Slide Rule

Professional, high quality instru- (Lancaster) July 46 ment . specifically designed COMMUNICATIONS Motor -Speed Control for electronic engineers and tech- A.G.C. for Receiver Audio Nov. 102 (Lanterman) 78 Positive- Ground Transistor Ignition nicians . made to our rigid Apr. System (Thornton) 85 specs by Pickett & Eckel. Has Business Radio Report (Sands) Jan. 51 Jan. 78 SCR Automotive Ignition special scales for solving react- Citizens Radio Rules Tightened Oct. System ance and resonance frequency Comments on the New CB Rules (Ward) Nov. 44 Simple Photoelectric problems. Accurately and quickly (Buckwalter) Nov. 42 Amplifier (Turner) locates decimal points. Carries Communicating in a High -Noise Nov. 104 Simplified Solid -State Color widely used formulas and conver- Environment (Devaney) Nov. 39 Organ (Lancaster) Jan. sion factors not found on any other Designing the I.F. Circuit (Tartas) Sept. 46 50 Transistor -Photocell slide rule. Comes complete with Design Trends in Receiver Frequency Color Organ (Blechman) 41 top -grain leather carrying case, il- Control (Kyle) Dec. 52 July Twin -T Oscillators for Electronic Musical lustrated instruction manual, 90 DSB and the Citizens Bander Instruments (Maynard) day consultation service all (Packham) Aug. 38 June 36 - Updated Transistor for just `514.95. Carries lifetime Microphones for Communications Ignition System guarantee against defects in mate- (Conhaim) Apr. 51 (Saatjian) May 51 rial and workmanship. Mixing Magic (Frye) July 54 Modulation Circuits for Solid -State HIGH -FIDELITY & AUDIO CB Transmitters ( Rheinfelder) Feb. 28 SEND COUPON TODAY. Adding VU Meter to Tape Recorder New Citizens Band Circuits (Hogan) Oct. 104 TO: CLEVELAND INSTITUTE (Buckwalter) Jan. 32 Audio -Compression Preamplifier OF ELECTRONICS New Citizens Band Circuits (Wright) Nov. 32 1776 E. 17th St., Dept. EW- 1G4,CIeveland, Ohio 44114 (Buckwalter) Mar. 46 Audio Level Clippers & Limiters _1 Please send me your electronics slide rule. New Citizens Band Circuits (Haskett) Feb. 51 I am enclosing 514.95. (If not fully satisfied (Buckwalter) May 46 Design of a High -Quality Transistor Power after 10 day trial. CIE will refund payment.; New Citizens Band Circuits Amplifier (Furst) Feb. Please send additional descriptive literature. (Buckwalter) July 34 34 Distortion in Phono Cartridges New Citizens Band Circuit (Kogen) _ 28 Nanle_ (Buckwalter) Oct. 54 Aug. íPlease Print) High -Fidelity Measurements New Facilities for WWVB and WWVL Jan. 39 -Science Address or Chaos? (Villchur) 33 New FCC Rules Now in Effect (Sands) May 30 Aug. Integrated Amplifier -Speaker New Look in Microwaves (Sands) Aug. 60 City State_ Zip (Gilmore) Noise Figures of V.H.F. Amateur Mar. 32 L Loudspeakers for Transistor Converters (Connelly, W6QID) Sept. 34 Amplifiers (Brociner) Plumbing the Microwave Circuit Jan. 42 Microphone Sensitivity Rating (Apperson, Jr.) June 23 Tuner cover 26 -54 and 83 -174 MC (Ramsey) May 31 in eight overlapping bands with Precision of U.S. Frequency Standard July 78 Mono Use of Stereo Phones (Trauffer) May 79 good sensitivity. Ideal for use with Single- Frequency Receiver (Kincaid) Apr. 44 New High -Quality Transistor amplifier or Hi Fi to listen to Air. State -Police Microwave (Lincoln) Feb. 48 Amplifier craft, CB, Fire, Polire and orne (Mergner) Transistorized Six -Meter Converter May 42 signals in the VHF 7).7,',7, ,. Noiseless Remote Switching (Martel) (Hejhall) Feb. 46 Mar. 60 Quieting Audio Switching Transistors versus Tubes for Two -Way Transients 355A AM /FM TUNER $4995 (Ives) Nov. 51 Radio (Rice) Nov. 48 Remote Volume Control (Martel) 62 Order today or sen c: for free catalog on fuli line Understanding Frequency -control July of converter, n.,; r_c_iver. for every application. R.F. Pickup in Audio Amplifiers Crystals (Conhaim) May 36 July 65 SCA Background -Music Demultiplexer Uniiunction C.W. Monitor (Cleary) Apr. 62 KUHN ELECTRONICS (Kuntz) Sept. 44 Which Channel Is It? (Sands) Feb. 40 Self -Protecting Transistor Hi -Fi CINCINNATI 17, OHIO Why Not U.H.F. Two -Way Radio? Amplifier (Kramer & (Rice) Mar. 42 Japenga) June 32 Tape- Recorder Equalization Curves GET (Burstein) July 38 COMPONENTS Transistorized FM- Demodulator INTO Stereo ELECTRONICS Capacitors -An Infinite Variety (Englund, Plus & Hansen) Dec. 34 -r I. tiainí to :rr.ress (Frye) Apr. 56 Transistors for Hi -Fi (Meyers, Jr. & cite it ions_ field encinecrs. Confused Fuse (Edwards) Jan. 100 Kahn) Apr. 42 specialists in communications. Constant -Voltage Transformer guided missiles. computers. Transistors for Music (Furst & Zide) Mar. 48 radar and automation Basic & Operation (Jaski) Apr. 40 Transistors vs Tubes for Hi -Fi rdv:mee,l courses in theory & High -Power Photocell (Cain) Mar. 44 (Mergner) Jan. 45 Engi- laboratory. Electronic Inexpensive D.C.- Variable vs neering Technology and Elec- Transistors Tubes for Hi -Fi (Chou) Feb. 36 tronic Technology curricula Inductor (Turner) Feb. 79 "Transistor Williamson" Stereo Power ttboth available. Assoc. degree in New Look in Transformers (Collins) Mar. 36 Amplifier (Sucker) Oct. 42 mos. H. S. also obtainable. Rating Unknown Power Transformers G.I. approved. Graduates in all EW LAB TESTED branches of electronics with (Duguid) July 24 Audio Dynamics ADC -16 Speaker armor companies. Stmt Feb- Shielded Cables (Buchsbaum) Nov. 36 4I, ruary Dorms. System Feb. 92 Using Slug -Tuned Coils (Tartas) Apr. 48 campus. -eptember.High school graduate Burgess Test Tape Apr. 20 or equivalent. Write for cata- Using Hook -up Wire (Tartas) Dec. 36 log. Dual 1009 Automatic Turntable Mar. 18 Eico Model 2036 Stereo Amplifier Aug. 12 VALPARAISO TECHNICAL INSTITUTE CONSTRUCTION Eico Model 2200 FM- Stereo Tuner Nov. 24 Dept. RD, Valparaiso, Indiana Enlarger -Phototimer Oct. 102 Electro -Voice "Coronet I" Speaker Light Dimmer & Power -Tool Control System Mar. 18

86 ELECTRONICS WORLD

www.americanradiohistory.com send for NEW FREE Electro -Voice EV -2 Speaker System Aug. 14 CRYSTAL CATALOG Model Microphone Feb. 22 THE 1965 Electro -Voice 664 NEW TRANSISTOR Electro -Voice 717 Microphone Jan. 20 with Electro -Voice "Sonocaster" Speaker Dec. 20 OSCILLATOR CIRCUITS PHOTOGRAPHY ANNUAL Fisher 500 -C FM- Stereo Receiver Feb. 20 Fisher SA -1000 Stereo Amplifier May 18 "Knight -Kit" KG -870 Amplifier Nov. 22 Citizen Band $195 "Knight" KN -990 Record Changer July 14 EACH Lahti U -2 Speaker System Sept. 16 Class "D" Crystals Harman -Kardon CA -65 P.A. Amplifier Jan. 18 s 3rd overtone - .005% tolerance - to RCA SK -46 Microphone Sept. 18 meet all FCC requirements. Hermetically 20 sealed HC6 /U holders. !a" pin spacing. Scott 310E FM- Stereo Tuner Apr. .050 pins. (Add 15c per crystal for .093 Scott 340B FM- Stereo Receiver June 18 pins). Shure Model 570 Microphone June 20 MI 23 megacycle frequencies in stock: 26.965. 26.975, 26.985, 27.005, 27.015, 27.025, 27.035, 27.035, 27.065, Shure Model 578 Microphone July 14 27.075, 27.085, 27.105, 27.115, 27.125, 27.135, 27.155, 27.165, 27.175. 27.185, 27.205, 27.215. 27.225, 27.255. Sonotone "Velocitone Mark IV" Matched crystal sets for ALL CB units (Specify equipment Cartridge May 18 make and model numbers) _- ______....__.__...... $5.90 per set PHOTOC7iRMSH` Shure V -15 Phono Cartridge Oct. 28 Uher 8000 Tape Recorder Dec. 18 RADIO CONTROL CRYSTALS ANNl°s:,at_ 1965 Is NC6 /U HOLDERS-SIX FREQUENCIES Vernon 47/26 Tape Recorder Oct. 26 In stook t« lmmedlaa dellwq (freauncies lI.t.d In mega. GÖÓe plce .v:úable. add 104! pireé 1.l.I 9paielafr°rmgllan ' INDUSTRIAL ELECTRONICS 27.041, 27.011. 27.141, 24 BIG 27.111. 27.211 $295`ACH Advances in Photosensitive Devices (rd a .r .ry.w r« .a.t.. and aaadunel FULL (Collins) Dec. 49 HERMETICALLY SEALED PRECISION GROUND Advances in Ultrasonics (Part 1) CUSTOM MADE NON -OVEN CRYSTALS 1000KC to 1600KC (Fund. Freq.) COLOR (Glickstein) Feb. 25 Prices on Request Advances in Ultrasonics (Part 2) 1601KC to 2000KC (Fund. Freq.) $5.00 ea. (Glickstein) Mar. 39 2001KC to 2500KC (Fund. Freq.) 4.00 ea. PAGES 2501KC to 5000KC (Fund. Freq.) 3.50 ea. Automated Ships Nov. 55 5001KC to 7000KC (Fund. Freq.) 3.90 ea. Battery Charger Uses an SCR (Dale) Sept. 79 7001KC to 10,000KC (Fund. Freq.) 3.25 ea. Binary Computer Codes and ASCII 10,001KC to 15.000KC (Fund. Freq.) 3.75 ea. ea. (Bukstein) July 28 15MC to 20MC (Fund. Freq.) 5.00 Bootstrap Circuits (Deboo) July 66 ORDER FROM CLOSER PLANT Enjoy the 1965 PHOTOGRAPHY Capacitance Transducer Systems ANNUAL -a superb showcase of color (Silver) Sept. 38 and black -and -white photos by outstand- TEXAS CRYSTALS Computer Input -Output Equipment DEPT. R -124 Division of ing photographers the world over! (Bukstein) Nov. 52 1000 Crystal Drive FORT MYERS, FLORDA Enjoy, too, the convenience of having Computer Logic Fundamentals Phone 813 WE 8 -2109 (Lukens) June 46 this year's edition delivered to your home AND -immediately! But you'll have to send for Data Flow in Digital Computers 4117 W. Jefferson Blvd. ( Bukstein) Aug. 36 LOS ANGELES, CALIF. your copy right now- the supply is going Diversify or Specialize (Frye) Jan. 58 Phone 213 -731 -2258 fast! Electronic Scanning Simplifies Telemetry Fill in and mail the special order form (Sands) July 36 CIRCLE NO. 229 ON READER SERVICE PAGE below- TODAY! (Note: Payment must Electronic Sirens (Kyle) Apr. 32 be enclosed at this low price.) Electronic Time -Delay Relays (Frenzsl, Jr.) Dec. 44 AUTOMATIC PARTIAL CONTENTS include these Portfolios: High -Speed Electronic Printer (Edwards) Dec. 46 * War Pictures by the late renowned photo- TRANSISTORIZED grapher, Robert Capa. Integrated Circuits (Solomon) Sept. 27 Light Dimmers for Home and Industry a new glamor book by Sam Haskins, * Preview of (Wolff) May 25 of Five Girls. author Liquid Temperature Controller (Scott) Nov. 46 BATTERY CHARGER * Abstract color by Wynn Bullock. Magnetic Core Memories (Rusch) Apr. 37 CHARGES 6, 8 or 12 V. BATTERIES * DALI -the surrealist as Philippe Halsman sees Magnetic Modulators (Silver) June 65 him. Magnetostrictive Delay Lines (Collins) Jan. 48 FULL 6 AMP RATE HEAVY GUAGE ALUMINUM CASE * Unusual Nudes by Masaya Nakamura. Measuring the "Sonic Boom" (Kyle) Oct. 58 Optical Scanners: Machines that Read BUILT -IN AUTOMATIC RESET The Wonderful World of Children by Michael * (Gilmore) Oct. 33 CIRCUIT BREAKER Pierce. "Radicians" at the DEW Line PLUS Intl. Portfolio, more color pages, etc. (Stocklin) May 48 Recharging Cadmium Cells (Frye) Oct. 68 Technical Institute (Baird) Mar. 79 GET THE DELUXE Temperature Sensitive Devices (Collins) Oct. 50 GOLD- EMBOSSED LEATHERFLEX Transducers for Industrial Instrumentation (Shiver) July 49 EDITION -only $2.50 prepaid. Understanding Telemetry (Buchsbaum) Apr. 25 FILL IN, DETACH & MAIL Vibration Instrumentation (Silver) Nov. 56 THIS ORDER FORM TODAY! OUTER SPACE Advanced Research for Communications ZIFF -DAVIS SERVICE DIVISION Dept. PA Satellites (Mackey, Jr.) June 64 589 Broadway New York, N.Y. 10012 Advanced Research for Meteorological Please send my copy of the 1965 PHOTOGRAPHY Satellites (Neil) June 61 ANNUAL as I've indicated below: Floating Spacecraft Tracking Stations Send me the regular edition. My $1.25, plus (LaCoste) Aug. 17 150 for shipping and handling (250 outside Goddard's Technical Manpower $2011) U.S.), is enclosed. (Hutchison) June 62 DI. Net Send me the Deluxe Leatherflex -Bound edition, Guest Editorial (NASA Goddard Space postpaid. My $2.50 is enclosed. (Add 500 out- Flight Center) (Goett) June 50 side U.S.) Allow two extra weeks for delivery. Manned Space Flight June 56 Guaranteed for 5 Years EW -124 Radio Telescopes: Past, Present & Future Ask your electronic or automotive distributor for (Giddis & Maggi) July 19 NAME Satellites in Space (Vaccaro) June 51 MODEL NO. BC2 Satellite Tracking, Telemetry, and MANUFACTURED BY J ADDRESS Communications (Mengel) June 58 Technology Spacecraft and Electronics ? /1011óC Packaging June 54 WORKMAN INC. I CODE SARASOTA. FLORIDA PRODUCTS, CITY STATE ZIP What is Goddard? June 52 1--(PAYMENT MUST BE ENCLOSED WITH ORDER.)) World's Largest Radar Telescope Feb. 45 CIRCLE NO. 238 ON READER SERVICE PAGE December, 1964 87

www.americanradiohistory.com NOMOGRAMS Capacitance Nomogram (Gross) Dec. 31 CB Range Nomogram (Karlin) Jan. 29 Delta -Y Transformation Nomogram (Teubner) Feb. 31 Meter Reading Conversion Nomograms (Jones) Aug. 24 Mid -Frequency Amplifier -Gain Nomogram (James) June 31 NEW 1965 GIANT CATALOG Phase -Shift Nomogram (Brindley) Nov. 31 Power & Resistor Charts (Jones) Sept. 33 Resistor Power -Rating Nomogram (Kyle) Apr. 29 Tape -Winding Nomogram (Blechman) Oct. 38 Voltage- Divider Nomogram (Moffat) Mar. 29 TELEVISION & RADIO Antennas and Grounds (Frye) Mar. 56 Automatic Degausser for Color TV (Buchsbaum) Sept. 53 of Cable TV: On the Move (Tepfer) Jan. 40 100's First -Hand Report on TV Tape Recorder new items for for Home Use (Snitzer) June 26 liste d time For Men Only (Frye) June 70 first Fraudulent Technician -A Minority (Frye) May 56 Harnessing the Antenna (Jones) Apr. 46 Helical Video Recorder for Television (Roizen) Oct. 47 Satisfaction Hidden TV Test Signals (Solomon) Apr. 34 GUARANTEED Hum from Crossed Connections (Risse) Feb. 86 or your Ignition Noise Problems (Frye) Aug. 52 money Japanese Color -TV Has Simple back! Controls Mar. 68 "Latter -Day" Enemies (Frye) Nov. 63 Maintaining TV Color Balance July 61 New Circuits for FM Portables May 64 New TV Designs for 1964 RDNIC (Buchsbaum) Mar. 51 New Pay -TV System to Start in July July 30 V 9 -Inch Color -TV Set RADID fi Nov. 110 ( :11 Non -Ignition Noise Sources (Frye) Sept. 58 t-í16 NUMBHONEBAIE1TOr Portable TV Sets (Solomon) Dec. 28 Radio & TV Interference 226 (Part 1) 1.606 (Haskett & Blount) 1NOEx May 39 ata Radio & TV Interference (Part 2) a}M- i (Haskett & Blount) June 40 Reducing U.H.F. TV Interference Sept. 69 f Repairing Miniature I.F. Transformers FOR 38 YEARS THE (McKinney) June 85 Results of EW Tests on U.H.F. OUTSTANDING Converters July 31 NO MONEY DOWN Service Shop of the Future (Frye) Dec. 56 PLUS REVOLVING V Showmanship in Servicing (Frye) Feb. 56 100's of pages V V Simplified Mexican Color TV CHARGE ACCOUNT packed with (Solomon) July 48 savings Alki,i1Y1A421 Stabilizing Vertical Height Sept. 89 BURSTEIN -APPLEBEE CO. Dept. 49, Television Servicing -Soviet Style 1012 -14 McGee St., Kansas City 6, Mo. BUYING GUIDE FOR: (Hannah) Jan. 78 Stereo & Hi -Fi Systems and Compo- U.H.F. Converters: Circuits & Design ' Rush me the FREE 1965 B -A Catalog. I nents Tape Recorders Electronic (Solomon) Feb. 41 Books Phonos & Rec- Parts, Tubes, U.H.F. ords Ham Gear Test Instruments Receiving Antennas Apr. 80 NAME I and Kits Cameras and Film Public U.H.F. Tuners for 1964 TV Sets Address Citizens Band Transistor (Buchsbaum) June 28 ADDRESS I & FM -AM Radios. Unique Color -TV Tubes and Systems (Solomon) Jan. 34 I CITY STAT I RUSH COUPON TODAY CIRCLE NO. 163 ON READER SERVICE PAGE TEST EQUIPMENT & MEASUREMENTS Additional Notes on Audio Sweep Generator (Manus) Nov. 112 PUT Automatic Electronic Testing (Gilmore) .Jan. 25 ZIP Capacitor Value Checker (Mangieri) July 44 Clip -On D.C. Current Probe (Bergh, In Kan & Forge) Sept. 41 1 Construct a Milliwatt Meter (Blair) Sept. 82 Converting Meter Scales (Apperson) Mar. 74 you Design of Simple "Q" Meter (Sandrock) Sept. 84 Diode Curve- Tracer & Analyzer (Kyle) June 44 JOHN JONES Your 380 WEST 33 57 Electronic Switch for Oscilloscope Include NEN YORK. NY ICC:I (Bammel) Feb. 38 Me RICHARD SMITH Electronic Tachometers (Kyle) May 34 ZIP CODE NUMBERS 220 EAST 85 57 Engine Temperature Indicator (Davis) Apr. 36 NEW YORK NY 0028 IN ALL ADDRESSES 4.5 -mc. Detector Alignment Probe Nov. 66 Frequency & Time Standards (Hudson) Aug. 20 High -Stability Crystal Frequency POSTMASTE R Standards (Math) Aug. 44

88 ELECTRONICS WORLD

www.americanradiohistory.com "550 FREE WHEELER"

To bring the "550 ", finest, feature- filled transistorized radio to the discerning C -B user in true, clear focus, WEBSTER offers an incen- tive in the form of an exceptional dividend, "the value wheel" com- prised of such essential (and high quality) accessories as antenna and noise suppression kit in addition to other functional items - car compass, magnetic clip board, 84 page road atlas, 10-code card. a have THE "FREE- WHEELER" (All illustrated above). Anyone who purchases "550" radio can these items, (valued at 64.00) for an additional 10.00-a 54.00 saving! DIVIDEND PACKAGE THE "550 "... A BRIEF SKETCH ... "550" transistorized C -B radio 179.50 Handsomely styled, book -size C -B radio with 11- crystal controlled channels, Universal mounting bracket N/C replaces vacuum tubes entirely with transistors and diodes. WEBSTER has applied Webster Model A -66 base -loaded advanced solid -state circuit concepts to achieve performance that is wholly mobile antenna with universal outstanding in every respect. There are no compromises. "550's" transmitter is cowl mounting bracket and complete full- powered to the 5 watts allowable by F.C.C. It incorporates special high - with 15' RG -58/U and fitting 28.35 level modulation techniques (pat. appd. for) that give 100% capability. Speech 84 page Road Atlas and Travel response is "shaped" for exceptional crispness and clarity. Guide with protective cover 2.95 The all- solid -state superhet receiver is highly sensitive, is particularly well Clip Board with magnetic hold -on. for weak signal reception with 10 db signal -plus- noise /noise ratio at Clings to any iron or steel surface 1.50 suited one -half microvolt! And it provides 60 db rejection to adjacent channel signals! Owners operating manual N/C Station log card w /10 -code on rear .35 Here are just a few of the dozens of functional features: Speaker on front panel ... of reserve audio Quiet, carrier operation is offered by an Auto Compass w /visi -dome dial, plenty power. no- clear markings, aircraft -type adjustable "squelch" ... and there is a highly effective series -gate noise limiter compensators, universal mounting with OFF switch. "550" uses no vibrators, operates direct from 12V car battery. bracket 5.95 Fixed station service is possible using separately available 117V AC supply. All "550's" are pre -wired to accept tone signaling units. Universal, cradle-type Model 6200 Noise Suppression System 24.90 mounting bracket is standard equipment. Total value 243.50 Your cost 189.50

Please rush full information on "550" and "Free-wheeler" dividend deal. THE "CLOVERLEAF" PACKAGE...

Same as above except that Model 6200 Noise Suppression System NAME is omitted ...Total value 218.60 Your cost 184.50 NUMBER STREET 317 ROEBLING ROAD, CITY ZONE STATE SOUTH SAN FRANCISCO, CALIF. NO. December, 1964 CIRCLE 251 ON READER SERVICE PAGE 89

www.americanradiohistory.com Now Big is Your Volt? (Jones) June 42 Ferris 24 -D CB "Microvolter" Mar. 63 How Capacitors Change V.T.V.M. General Atronics K -12 -R Monitor Readings (Duguid) Oct. 53 Oscilloscope July 58 How Linear is Your Sweep? Oct. 91 General Radio Type 1396 -A Tone -Burst SELLING THAT Kelvin Color Temperature June 73 Generator Aug. 69 low "O" Resonance (Tusinski) Nov. 90 Heathkit HO -13 Spectrum Monitor Aug. 68 Measuring Filament Voltage Aug. 65 Hewlett- Packard 208A Test Oscillator June 82 Miniature Regulated Power Supply Hewlett -Packard 214A Pulse RECORDER? (Shields) Feb. 74 Generator Apr. 74 Miniature Voltage Regulators Houston Instrument VM -77B A.C. (Burgess) Feb. 82 V.T.V.M June 82 I BUYING A I Multi- Output Zener Voltage Regulator Idalee Model 100 A.C. Decade Voltage (Reed) Feb. 94 Source May 72 New Approach to High- Frequency Keithley 409 Picoammeter May 74 Measurements (Ferrous) Aug. 41 "Knight -Kit" Ten -2 CB Checker Feb. 64 RECEIVER? ; Piano Tuning -The Electronic Way Mar -Con DRT -100 Techometer June 83 (Van Veen) Sept. 56 Mercury Model 1400 In- Circuit Capacitor Precise Measurement of Radio Tester Dec. 64 Frequencies (Johnson) Aug. 47 Panco Resistance Calibrator Jan. 68 Printed Board Repair (McKinney) May 69 H.F. Parks Lab. ID -1017 Diode Tester Nov. 70 '*XAV p R.F. Response Measurement (Tusinski) Feb. 37 RCA WR -50A R.F. Signal Generator Mar. 62 SCR Tester (Hopkins) Jan. 56 Scientific Columbus MMA -1 Gaussmeter Simple Dwell Meter (Penn) June 43 Adapter Apr. 72 Simple Square -Wave /Pulse Adapter Seco Model 88 Tube Tester Feb. 68 (Shields) Mar. 77 Seco Model 980 Color -Bar Generator Nov. 68 Simple Transistor Tester (Content & Sencore CG126 Color -Bar Generator Jan. 64 Morse) May 50 Sencore MX129 FM- Stereo Multiplex Simple Transistor Tests (McKinney) Aug. 63 Generator Dec. 64 Tone -Modulated Frequency Calibrator Sencore PS127 Oscilloscope Oct. 94 (Ives) Oct. 56 Sennheiser Model ZP -2 Audio Impedance Transistorized Audio Sweep Generator Tester July 58 (Douglas) Aug. 71 Tequipco Model 4 Transistor Tester July 59 Transistorized Color -TV Pattern Texas Crystals TC -3 Alignment Generator (Stewart) Nov. 96 Generator Nov. 72 Units and Standards of Electrical Waters Model 343 Frequency Meter Sept. 76 Measure (Harris) Aug. 29 Western Reserve Electronics Model Unusual D.C. to D.C. Supply 300 Digital V.0 M Oct. 92 (Winklepleck) May 62 Voltage Regulator Design (Frenzel, Jr.) .May 52 ELECTRONICS WORLD runs a Hot Wide -Range Wow & Flutter Meter TUBES & SEMICONDUCTORS Line into the 201,000 electronics (DiElsi) June 76 Early Vacuum Tubes (Watson) Dec. 42 professionals who buy the magazine 4- and 5 -Layer Semiconductor Diodes PRODUCT REPORTS each month. And, for only 35¢ a (Lancaster) Oct. 61 A & M Instrument Model 1300 Universal word, a personal classified ad will Gate Turnoff Controlled Rectifier Lab Standard Feb. 66 (Pippen) help you make Aug. 46 your connection. Ballantine 365 D.C. Volt- Ammeter Mar. 64 Innovations in Receiving Tubes B & K Model 360 V.O.M. Jan. 64 (Collins) Sept. 54 ELECTRONICS WORLD has B &K the Model 445 CRT Tester - New SCR Developments (Lancaster) Dec. 25 largest audience of its kind in the Rejuvenator Apr. 72 Selecting High- Frequency Transistors Bird Model 6154 R.F. Wattmeter world, and this creates an ideal Dec. 66 (Hejholl & Thorpe) Sept. 50 Boonton 89008 Peak -Power Calibrator May 72 Semiconductors for Power Supplies market place for you. Actually, when Budelman 17A4 CB Frequency Meter Aug. 68 (Gutzwiller) Nov. 27 you get together with your co -pro- C -W Engineering MX -4 Stereo Signal Substituting Silicon for Germanium fessionals, you may find that many Generator Sept. 74 Transistors (Hamlin) Dec. 39 are near neighbors. Yet your mutual Eico 369 TV /FM Sweep- Marker Traveling -Wave Tubes (Jarrett) Mar. 25 Generator Sept. 74 needs may be met only through the Tubes Clue to Air Crashes (Halliday) .Jan. 83 EMC Model 801 R -C Bridge and Unijunction Transistor (Pippen) Jan. 46 medium of our classified columns. Capacitor Checker Oct. 94 Using Zener Diodes (Math) Nov. 88 Take advantage of our special personal rate of 35¢ a word (including NIGHT -LIGHT CONTROL name and address) II0T/1 CREDITS Page Credit HE G -E -X6 sulfide photo- NO MINIMUM REQUIRED cadmium 18 Martel Electronics Sales, Inc. -1- cell can be used up to a saving of 25¢ a word 20 Electra- Voice, Inc. 250 volts peak a.c. or d.c. in a variety from our commercial 28 Sony of applications. In the circuit shown, rate of 60¢. 32 (top) .... International Business Machines Corp. when the cell is illuminated, it effectively 32 (bottom left), 33 (bottom right) short -circuits the coil. As the ambient Radio Corporation of America light decreases, the cell resistance goes 32 (bottom right) ... Sperry Gyroscope Corporation up, causing more current to flow through 33 (top left) International Telephone and Telegraph Corp. the coil winding until the magnetic field A small investment can bring quick 33 (top right) Honeywell, Inc. within the coil form is sufficient to close . results, and complete data is , 33 (bottom left), 38 (Fig. 4) Collins Rodio Company the G -E -X7 reed switch. This turns on 42 printed in the Classified Advertis- Science Museum of London the 15 -watt lamp. 43 Marconi Company, Ltd. ing Section. Write your ad and mail 44 (top left) Amperite Co., Inc. RI i0 it today, with your payment to: LAMP 44 (center & right) -Seal M v . Electra Corporation WATT MAX IN1696 MARTIN LINCOLN 46 Century Electronics 8 Instruments, Inc. R2 Is IOK Classified Advertising Manager 49 (center) Claires Corporation 07 v. ] MATT I RJ A.C. 1.3K WORLD 49 (bottom) Eastman Kodak Company A To BO GE-x7 ELECTRONICS t. WATT 200V GE-X6 REED SWITCH One Park Ave., N. Y., N. Y. 10016 64 Mercury Electronics Corporation PHOTO C LI TMOUNTED , CELL E INSIDE 66 Sencore LI FEBRUARY ISSUE CLOSES DEC. 4th , Bird Electronic 68 Corporation 111 75 Heath Company LII0,000 TURNS 39 WIRE ON 2 COIL FORM

90 ELECTRONICS WORLD i www.americanradiohistory.com ELECTRONICS MARKET PLACE COMMERCIAL RATE: For firms or individuals offering commercial products or services. 60C per word (including name and address). Minimum order $6.00. Payment must accompany copy except when ads are placed by accredited advertising agencies. Frequency discount: 5% for 6 months; 10% for 12 months paid in advance. READER RATE: For individuals with a personal item to buy or sell. 35C per word (including name and address). No Minimum! Payment must accompany copy. GENERAL INFORMATION: First word in all ads set in bold caps at no extra charge. Additional words may be net in bold caps at 10C extra per word. All copy subject to publisher's approval. Closing Date: 5th of the 2nd preceding month (for example, March issue closes January 5th). Send order and remittance to: Martin Lincoln, ELECTRONICS WORLD, One Park Avenue, New York, New York 10016

CONVERT Television to Oscilloscope and Signal Tracer. FOR SALE Plans $1.00. Reagan, 1119 W. Maine, Enid, Okla. REPAIRS AND SERVICES CATALOG of over 200 different slide rules, calculating aids. Send 1OC. Dyna -Slide, 600 South Michigan, Chi- TRANSISTOR Ignition coils, components, kits. Advice TV Tuners Rebuilt and Aligned per manufacturers spe- Free. cago, Ill. 60605. Anderson Engineering. Wrentham 5, Mass. cification. Only $9.50. Any Make UHF or VHF. We ship COD Ninety day written guarantee. Ship complete with JUST starting in TV service? Write for free 32 page ANTIQUE EDISON Cylinder Phonographs. Released From tubes or write for free mailing kit and dealer brochure. catalog of service order books, invoices, job tickets, Storage. Display Price sheet sent. Tracy Storage, 114 JW Electronics. Box 51B. Bloomington, Indiana. phone message books, statements and file systems. State, Brewer, Maine. Oelrich Publications, 6556 W. Higgins Rd. Chicago, TELEVISION Tuners -Rebuilt, Air Tested $9.00 Plus III. 60656. Shipping. Guaranteed. Texas Tuners, Box 222, Robert FLIP -FLOPS: Transistorized circuit mounted a on Lee, Texas 76945. printed circuit board with plug -in connector. Operation GOVERNMENT Surplus Receivers, Transmitters, Snoop - up to 10,000 cps in set -reset or trigger mode. Can be RCA TEST Equipment, Authorized Repair & erscopes, Parabolic Reflectors, Picture Catalog 100. Calibration used in counters, registers, Center, Nationwide. Bohr Meshna, Nahant, Mass. shift and memories with no Edwin /Electronics, Box 4457, additional circuitry. $3.87 complete. Send for free lit- Chattanooga, Tennessee 37415. TRANSISTORIZED Products importers catalog. $1.00. erature. KOMTRON, Box 275, Little Falls, N.J. 07424. Intercontinental. CPO 1717, Tokyo, Japan. HICKOK TV -FM Alignment Generator, Model 695, with RECORDS DIAGRAMS for repairing Radios $1.00. Television $2.50. manual. Like new. Built -in bias supply and voltmeter. 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Schematics, 5AV8 68E6 6CL6 6507 747 'ZOOS 26 5AW4 OBF5 6CM6 65F5 12076 35A5 5879 .90 8I IA New 3.95 618 Fourth Street, Newark, N.J. 07107. 51307 708 3585 68E6 6CM7 65F7 704 12AT7 5881 1.95 5J6 613066 6CN7 6587 785 12AU6 35C5 815 2.50 578 613146 6056 65K7 786 120U7 35L6GT ANSA Fone Schematic $2.00. Jerry Reeves, 1815 4th 5U4G 6836 6CD6 65L7GT 35W4 6146 2.45 82913 7.00 5U8 707 12006 Street, SeaBrook, 68K5 60E6 65N7G7 ]88 12AV7 3504 6159 2.75 832 3.00 New Jersey, 08303. 504G 6BK7 6006 6507 7C4 12AX4CT 352567 5V6GT 6BL7GT 6F6 6557 705 120%] 37 6201 1.00 832A 5.50 5%8 606 674 39/44 PHOTO 503GT 6BN6 ]C6 12AZ7 Facsimile Transceivers TT -1F /TXC -1 with Power 6BQ6GT 6J4 608 7C7 12134 42 6900 1.95 a66A 2.95 5046 6007 685 6U8 7E6 12aA6 43 Units PP -86E /TXC -1, used, like new, tested, ready 6A7 5805G 637 606 12BA7 45 1:46 6K6GT 6W4GT E7 50A5 EXTRA SPECIALS: to use. Best offer. Dale McLaughlin, RFD 7, 6626 7F7 I2BE6 Frederick, 5085 r 2 volt VIB Doe 12BF6 SOCS l Maryland 21701. 120H7 6 12 volt New VIB $1.49 taons 50L6GT 12667 50116 50 uatt 251( Sorayue. Resistors30C METERS -SURPLUS, new, used, panel and portable. Send for list. Hanchett, Box 1898, Riverside, Calif. CRO P.O. Box 55 Park Sta. WRITE DEPT. ®FOR OUR FREE ELECTRON TUBE CO. Paterson 3, FOMPLETE LIST NEW supersensitive transistor locators detect buried N.J. OF TUBES & SPECIAL gold, silver, coins. Kits, assembled models. $19.95 up. PURPOSE TUBES Not Connected With Any Underwater models available. Free catalog. Relco -A22, ALL TUBES SENT POSTAGE PAID. Please send 35c handling for orders under $5. Send Tube Box 10563, Houston 18, Texas. Other Mail Order Co 125% dep. on C.O.D. orders. Send approx. postage on Canadian and foreign orders.

December, 1964 CIRCLE NO. 198 ON READER SERVICE PAGE 91

www.americanradiohistory.com ELECTRONICS ENGINEERING AND INSTRUCTION BRAND NEW 011% FCC LICENSE in six weeks. First class radio telephone. UNITED'S FIRST QUALITY Results guaranteed. Elkins Radio School, 2603C, In- wood, Dallas, Texas. DISCOUNTS up to TUBES OFF USED Correspondence Courses and Books sold and rented. Money back guarantee. Catalog free. ONE FULL YEAR' NOT USED! NO PULLS! ? (Courses GUARANTEED WHY PAY MORE Bought). Lee Mountain, Pisgah, Alabama.

Tube Price Tube Price Tube Price Tube Price Tube Price Tube Price I Tube Price Tube Price 0A2 ..80 3DZ4 ../9 6ÁJ5 1.95 6CU6 1.05 6308 .74 8CM7 ..69 12E08 ..78 19C8 .1.05 ELECTRONICS! Associate degree-29 months. Techni- 043 ..90 3EH7 ..60 64J8 1.73 6CÚ8 ..99 6JE6 2.00 BCN7 ..95 12E88 ..95 19CL8 ..57 cians, field engineers, specialists in communications, DÁ40 1.35 3E.í7 ..6n 6ÁK5 ..90 6CW4 1.09 6JE8 1.50 8CS7 ..72 12FX5 ..64 19E48 ..77 0B2 ..80 3ER5 ..86 64K6 ..80 6CW5 ..78 6J5 _ ..92 8CX8 ..89 12FX8 ..88 19607 1.99 missiles, computers, radar, automation. Start February, 6CX8 1.82 6J6 .69 8E88 .92 12646 ..63 I9HV8 1.44 OB3 1.20 3FH5 ..63 64L5 ..35 September. Valparaiso Technical Institute, Dept. N, 0C3 ..75 3F55 _74 6AL7 2.10 6CY5 ..68 637 . 1.65 8EM5 1.15 12GC6 1.04 19JN8 1.20 OD3 .73 30K5 _59 6ÁL11 1.05 6CY7 .69 6J8 . 1.40 8E77 1.08 126E5 .93 19Q9 . ..75 Valparaiso, Indiana. 003 2.75 30W5 ..53 64M8 .76 6CZ5 1.80 6J11 1.83 8FQ7 ..54 12GW6 1.02 1978 .83 054 1.20 3HÁ5 ..99 6A N4 1.59 6C27 1.95 6JH6 .55 8GN8 ..97 12J5 . . ..95 2050 .1.05 64N5 2.65 604 . 1.75 6JH8 1.85 BJVB ..93 12J8 ..82 23EX6 1.47 0Z4 ..77 31185 . .59 .. HIGHLY -EFFECTIVE home study review for FCC com- 1A3 ..73 3H58 1.29 64N6 2.45 606 .67 6.11(8 ..68 8KA8 ..84 121(5 ..73 21075 1.02 I45 ..73 3Q4 ..61 64N8 ..91 6010 1.95 6178 . 1.75 948 ..98 12880 ..87 22BH3 .74 mercial phone exams. Free Literature! Cook's School 64Q5 60A4 .66 6JV8 . ..68 9AU7 67 12KBM 22BW3 1.43 146 ..73 354 ..73 .52 2.75 of Electronics, Box 10682, . Pittsburgh, Pa. 15235 (Es- 197 1.39 3V4 ..61 6406 1.00 6DÁ5 1.28 6JZ8 ..83 9887 1.32 12L6 . ..71 22DE4 ..67 1Á8S .77 4ÁU6 ..52 6407 1.73 6085 .67 686 .. ..61 9CL8 ..77 12L8 -50 22306 1.06 tablished 1945, Jackson, Miss.) 14E4 1.34 4ÁV6 ..40 6ÁQ8 ..77 6006 1.30 6K7 .95 9E48 ..66 120767 2547 .3.00 14F4 1.30 4646 ..85 6AR5 ..53 6DC6 1.33 687G ..75 9U8 . .80 1.35 25ÁC5 2.00 1AG4 2.20 4BC5 6A86 .87 6DE4 ..68 68807 ..87 104111 1.09 1207M 2.50 2541(4 .66 ..56 6K8M 1.85 10805 .89 12R5 25ÁV5 1.00 REI First Class Radio Telephone License in (5) weeks 14J5 . .48 4BC8 1.00 6988 2.00 60E6 ..59 .75 14X2 4BL8 64611 1.70 613E7 ..73 6811 1.50 1008 .1.03 1254707 254X4 . .68 Guaranteed. Tuition $295.00. Job placement free. 183 60 ..61 6455 ..59 6006 .60 68D8 1.12 100E7 ..73 .87 2588 .1.73 ..77 413146 72 61(78 2561(5 Radio Engineering Institute, 1336 Main Street, Sara- 1B5 ..98 41307 6456 . ,78 60J8 1.17 ..80 10E07 .86 12547M .89 99 6K U8 1.05 10EM7 1.75 25806 1.12 105 . ..73 41358 ..96 6A57 2.75 6086 .57 2.50 sota, Fla. íC6 ,.73 6458 .83 60116 1.76 6KZ8 .67 IOEW7 ..97 í25C7 ..78 25C5 -51 Á8U8 71 SOCNB 1DN5 ..53 48Z6 ..56 64533 1.98 6087 1.35 6186 1.00 .93 125F5GT 25CÁ5 1.85 I DSGP 6476 ,.47 6005 1.89 6L5 .90 101478 1.12 .98 25CD6 1.50 LEARN ELECTRONIC Organ Servicing at home. All makes ..98 gg27 3.00 10JA8 .92 2501(4 1.05 107 .78 4CB6 ..55 6478 ..84 6006 1.05 616CÁ 1.40 125F5M 108 2.20 6AÚ4 ..83 6087 .73 61668 1.50 10KU8 1.07 1.75 250N6 1.50 including transistors. Experimental kit- trouble -shoot- ÁC56 ..59 1.40 6166 ..98 l0Y 25EH5 ..53 1E5GP ..98 4CY5 ..70 6AÚ5 ..50 6054 125F7GT ing. Accredited NHSC. Free Booklet. Niles Bryant 61355 1.30 61660 1.65 11CY7 73 25E5 . ..56 1E7 ,.87 40E6 ..60 64U6 ..50 .65 6DT5 ..79 6L6M .2.50 IIJE8 1.70 2516 . ..55 School, 3631 Dept. A, 1F4 ..68 401(6 ..58 6A U7 .,70 125F7M Stockton, Sacramento 20, Calif. IFS .73 6ÁU8 ..85 6076 ..51 6L7 ..1.05 11KV8 1.52 1.75 25W4 ..66 íF6 4076 ..53 6078 .92 6M11 .1.85 1244 .59 25Z5 .1.10 1.20 ÁE87 ..60 64V5 ..89 12567 ..95 BE YOUR OWN Television Repairman! Instruction Book, 103 ..77 6ÁV6 .39 60VÁ 2.65 606 ..1.45 12A5 -95 12567M 25Z6 .73 gEJ7 ..60 . 1246 85 270135 1.59 104 .69 4EM6 64V11 1.65 60W4 ..90 6N7 ...96 1.30 $1.25. Abrilz, Westhampton Beach, N.Y. 11978. 106 ..80 ..94 6ÁW8 ..88 60W5 ..99 6P5 ..95 12A7 1.45 í25H7 1.39 32ET5 ..53 IH4 135 ÁE58 1.90 60ZÁ .78 60707 1.27 1248 3.00 32L7 .85 4EWG ..56 64X3 .,133 12411 1253767 IH5 87 64X4 ..64 6E5 . 2.25 607 -M 1.45 1.74 .99 33GY7 1.40 IH6 ..73 6AR5 .,73 6E47 ..88 6011 .1.05 124135 ..58 125.17M 341305 ..51 qG M6 ..58 6E48 ..77 687 ..1.25 12AC6 ..53 34GD5 ..79 1J3 ..77 4058 1.29 6A %7 .62 1.75 1J6 ..98 64X8 1.45 6EB5 ..71 654 ....413 12406 .48 125K7GT 3545 -85 TUBES IJ6 ..98 4025 1.49 6E135 ..91 657 ....90 124E6 ..48 3585 ..95 4HC7 ..73 6ÁY3 1.15 124E7 .93 11(3 77 6428 1.30 6EH7 1.33 658 ..74 "92 125K7 -M 35C5 ..49 114 ..66 Á8C7 ..73 13BÁ 3.80 6EH7 ..59 65476T .97 124F3 ..65 35EH5 ..55 4HM6 ..56 6EN8 ..77 6547 -M 1.25 124E6 .65 2.00 35L6 ..58 1144 . .87 41(54 685 4.00 12AG6 ,.60 12817 ..78 1LÁ5 2.50 73 687 2.00 6EJ7 ..77 65677 1.15 12507 ..65 35W4 .40 TUBES -TV, Radio, Transmitting And Industrial Types 1LÁ6 ,_87 4876 .99 688 2.00 GEMS ..75 6507 1.35 12AJ6 ..60 3554 1.63 Á3C6 í.6q 12AL5 .95 1250767 3523 1.20 11134 ..87 61310 1.39 6EM7 ..80 6507 ..70 .89 At Sensibly Low Prices. New, Guaranteed, 1st Qual- ILCS 4306 1.64 :EN6EQ7 . -70 65F5 12AL8 ..93 35Z5 .58 1.05 6093 1.15 75 . . 12577 .60 Top Name 11 C6 5AM8 .77 6846 ..48 ..88 6SF7 1.00 12.4011 1.06 5041 . 3.95 ity. Brands Only. Write For Free Catalog 87 SAN8 ..88 12.405 12V6 . -60 1LD5 61347 ..98 6E55 .68 6567 . 1.10 ..58 5045 1.49 1.95 5405 .52 12476 ..48 1266 ...69 5085 or Call WAlker 5 -7000, Barry Electronics, 512 Broad- ILE3 ,87 6688 .88 6E58 1.39 65X7 ..97 12X6 ..68 5484 6ET7 .90 12477 ..74 ...69 5005 . .51 ILGS 1.98 1.40 6804 2.1 1.04 653767 12X4 ..45 way, New York N.Y. 10012. 11H4 ..87 SÁ56 1.75 6805 ..513 6EÚ7 ..66 6537 -M 1.02 12.4U6 ..49 50004 ..46 5478 ..81 6EÚ8 ..77 651(707 .63 12407 ..59 13087 ..73 50E115 ..95 1105 ..57 6007 ..88 12AV5 1387 .72 RADIO & TV Tubes -33C each. Send for free list. 54V8 ..98 6BC8 BENS . .73 651(7.M 1.46 ..93 50HC6 ..86 IN5 87 1.00 12AV6 13E13E817 1.84 11.5 138 SAZ4 .73 6805 1.20 6E W6 ..55 651767 ..81 ..39 I3FD7 50HK6 ..54 Cornell, 4215 -W University, San Diego, Calif. 92105. 588 . 1.30 . 12AV7 ..80 ..78 5006 ...59 105 1313 6806 . .55 6EW7 ..78 6507 ..63 5603 ..50 6507 .92 12AW6 ..98 137 ..78 50X6 . 184 80 6883 ..71 6856 .73 ..78 ..67 BEFORE you buy receiving tubes, test equipment, Hi -fi IRS 75 5888 ..81 68E6 ..53 6EX6 3.65 6587 1.00 124%3 ..63 14446E7 5076 .95 5087 ..84 6E75 6557 ..95 12AX4 ..65 1444 1.10 5077 .1.10 components, kits, parts, send for your giant 154 1.05 6865 . .88 ..88 1445 1.10 etc.... 155 51307 ..99 68E6 .42 6E28 .93 6527 ..95 124X6 ..62 6OFX5 ..60 ..70 12.4X7 .61 1447 .35 70L7 .89 free Zalytron current catalog, featuring Standard brand 174 ..70 SBR8 ..81 60F8 1.70 6FÁ7 1.32 674 ..96 14867 1.35 ITS ,.80 SETA .713 6666 1.65 6FD7 2.37 618 .83 12427 1.42 117L7 .2.50 tubes; RCA, GE, etc. brand new premium 1.31 6FD7 1.79 12427 ..84 1486 .87 117N7 3.95 -all quality 1U4 70 5BW8 6686 ..66 6U5 1.75 1488 1.75 5C08 ..79 6F4 . 2.35 1171.7 3.95 One guarantee at 1U5 . .63 613118 ..94 6U8 81 individually boxed. year -all biggest 5CL8 ..74 6FSGT 1.10 6V3 1.10 12846 ..49 14C5 1.50 117Z3 ..83 IV 1.05 6BJ6 ..63 146 1.75 discounts in America! We serve professional service- SCM8 . .88 6F5M 1.50 6V6GT .52 12847 ..82 22 . . ..95 1X20 ..80 6EJ7 ..77 12806 14E6 1.25 IZ2 3.25 5CQ8 ..82 6638 1.45 666 .67 676M 2.50 ..48 14E7 1.25 24A .95 men, hobbyists, experimenters, engineers, technicians. 243 2.50 SCZS ..70 661(4 1.75 6F6M 1.25 6W4 ..60 1213E3 ..67 26 ..1.10 50E8 6F7 2.50 1213E6 ..51 1467 .87 27 ..1.50 Why pay more? Zalytron Tube Corp., 469 -W Jericho 245 1.25 .81 6885 . .93 6W6 ..69 14 1.75 . 12BF6 ..58 2807 .1.50 246 1.10 50J4 .. .77 6087 . ,84 6F8 1.25 6X4 ..39 Turnpike, Mineola, N. Y. 247 1.50 SEAS ..78 60L7 1.05 6665 2.15 6X5 ..51 12BH7 ..75 14GTS8 ..60 30 ..1.15 6607 ..67 ..78 1281(5 ..98 14X7 1.60 32 ..1.00 24F44 . .93 5E58 1.11 6BL8 ..97 6X8 6FG8 ..54 14J7 1.45 33 _85 7" TV test tube -$6.99. Tubes -6146 -$2.95; 6211 2AH2 1.23 SEUB ..78 6884 ..60 ..65 6Y6 1.00 13SL2 14N7 1.25 .. 2,452 ..70 SEW6 . 56 66N6 ..70 6FH5 .73 7A4 ..87 ..97 34 . ..79 (12AU7 39C, 3 for 1487 . .87 equiv.) $1.00. Germanium diodes, 12606/ . . . 5F07 , .67 613148 6FJ5 2.25 745 35 -51 . .85 283 .98 ..74 87 CU6 1.11 14 .87 287 . .70 SFV8 ..77 6005 6FM7 ..77 746 . 1.15 36 ....95 tested, equiv. 1N34, 1N60 etc., 30 for $1.00. Tophat ..63 12887 ..72 1457 1.25 37 26N4 ..62 SOUS ..62 6806/ . 6FQ7 ..56 747 ..87 70 12BV7 . 14W7 1.25 silicon rectifiers, 750 MA piv 750. Transistors, .66 .74 38 . -90 -1000 2CY5 . .68 SGM6 1.04 6CU6 1.08 6F55 ..74 748 2021W ..79 50X6 .54 6EQ7 ..98 6666 ..68 7407 Í.I5 12BW4 1.09 1454 1.25 39/44 ..55 tubes, resistors, condensers etc., bargain priced. Free 1.49 6EN8 .77 7ÁF7 1.45 12857 ..75 1454 1.25 2E45 . .68 5HC7 6888 ..80 154E11 2EN5 ..49 S1(G8 ..80 6858 ..93 6FW5 1.96 7ÁG7 .87 12826 ..75 42 . 1.25 catalog. Arcturus Electronics, Dept. ZD, 502 -22nd St., 6FW8 12827 ..84 1.5 43 2885 3.65 5J6 -70 68U8 . .68 4.25 7ÁH7 1.25 ..1.20 3205 .56 15F 1.15 45 Union City, N.J. 07087. 2FH5 . 51(68 1.24 6FY5 1.25 7AU7 .63 2.00 .74 6BV8 1.23 12C45 15 1.29 2F05 ..99 5T4 ..84 GOW8 1.35 605 . 1.23 784 1.45 ..60 46 2FS5 578 66X7 6060 1.00 785 ..87 12CN5 ..54 15186118 6 1.28 47 2.10 ELECTRONIC TUBES -Top Brands SOLD at substantial 1.47 ..84 1.09 12CR6 ..65 16403 ..42 21185 ..59 5U4 ..58 6655 1.24 66E5 ..92 786 ..87 48 3.50 Dis- 20W5 2.40 5U8 ..82 61376 _60 60F5 1.75 767 .87 12C56 .63 16403 1.42 SO 1.45 savings! (Minimum Order $15.00) Authorized GE 788 1.25 12CT8 1.60 1741(3 . .51 53 2HK5 ..98 5V3 ..88 6137Á ..64 6088 ..78 12CU6/ 174X4 ..65 ..2.98 tributor. Send for FREE Buyers' Guide for all your 2X2 . -60 5V4 1.45 60Z6 ..54 601(5 ..59 7C5 1.35 55 1.90 2X24 1.30 5V6 ..54 6BZ7 ..99 601(6 .77 7C6 ..87 806 1.05 174X3 . .68 56 95 Tube Requirements. TOP CASH PAID for your excess 12CX6 178E3 . . ..52 .68 57 . 342 . 1.20 5W4 1.75 613Z8 1.06 GGL7 2.35 7C7 ..89 1.35 (New ONLY Quantities). Metro- 343 ..74 5X4 ..90 6C4 .43 6GM5 ..78 7E5 .87 1204 ..67 178E3 .57 58 1.85 inventory -Commercial 1.15 121365 ..67 1785 1.10 59 344 . _58 5X8 ..80 6C5 . 1.40 60M6 ..58 7E6 2.50 politan Supply Corp., 443 Park Avenue South, New 1.25 1213E5 17053 . .86 345 . 1.10 553 ..44 6C6 . .87 6GN8 ..92 7E7 ..60 714 120E8 17C5 .18 York. N.Y. 10016. 212-MU 6 -2834. 34 r4 ..99 523 . 1.50 6C8 ..88 6007 1.89 7EY6 .73 ..8I 75 . 1.90 5Z4 . 1.75 6087 ..78 7F7 1.75 121318 .85 1704 .1.17 76 3415 ..44 6C47 1.35 12006 1.02 170E .67 .1.40 3472 ..71 6A3 . 2.75 6C10 1.55 6075 1.00 7F8 .88 77 .1.25 CASH for following tubes having good filaments: All 34116 ..52 644 ..78 6C44 ..47 6075 98 107 1.25 12007 1.33 17DE4 1.29 78 .1.15 3466 _40 645 3.00 6C45 6GV6 1.85 7H7 1.35 12057 . .82 17130 04 .04 80 .1.25 types DeForest, Arcturus "blue glass," and Daven ..77 1.67 12075 .74 17006 1.04 39W3 ..72 6A6 . 1.95 6CR5 2.05 6GW6 1.00 7HG8 81 . . 1.25 . 12077 . .77 17DQ7 1.85 Brands. Sodion D -21, S -13, S -14. Speed 291, 293, 295. 'R^ . 647 1.10 6C86 6GW8 1.50 7J7 1.95 82 1.23 3.45 ..53 12078 .76 176E5 1.70 387 . 1.35 668G7 1.10 6C06 1.47 60X6 ..55 787 1.95 63 2.10 McCullough 403. Raytheon "BA" rectifier. Emerson 3R A6 .a9 648M 1.15 6CF6 ..95 60X8 1.25 7L7 1.95 12DW1 1.20 175 . .99 84 '6Z4 .95 1.95 120W8 .87 1766CV5 .01 3,'.CS . -61 6A84 .44 6CG7 ..59 6055 .53 7N7 85 ..98 multivalve. For private collection. Earle Young, 450 ,1E6 ..54 6465 3.00 6CG8 ..78 6656 1.10 707 -.87 12058 1.75 17H 1.01 5881 .2.95 .13i14 ..76 64137 1.00 6CK4 ..69 6CZ5 ..53 7R7 ..87 120Z6 . .60 17H3 ..18 6336 .5.95 Magee Ave., Rochester, N.Y. 14613. 38,13 ,.73 64C5 1.95 6016 6H45 ..99 757 .87 12E46 .99 17 1.18 6146 .3.95 ..92 12EC8 1.38 17L66 56 3,104 _76 64C7 . .93 6CL3 ..77 6HB5 2.09 7V7 1.85 6550 .3.75 3656 _56 6AD7 3.25 6CM6 1.45 6HFS 1.90 7W7 1.85 12E05 .60 17 .. .93 807 ..70 .93 3876 . .54 6ÁE5 2.50 6CM7 ..67 6HF8 1.25 7X6 1.25 12E06 ..60 17J28 ECC83/ 171L ',FIG ..Sa 64F3 ..71 6CM8 1.02 6H08 . .79 7X7 1.85 12EK6 ..60 06 1.20 124X7 1.60 PLANS & KITS ? ^.E5 ..56 64F4 ..99 6CN7 .68 6HJ8 ..80 7Y4 67 12E16 ..48 17W6 .. .99 EL34 / 3C,6 ..6: 6AF'A ..99 6CQ4 1.35 6HK5 ..59 777 1.25 12E18 ..86 1845 .47 6CA7 3.75 3655 ..56 GAFE 2.50 6C07 1.80 6HL8 ..71 7Z4 ..87 12EZ6 .55 18F/6 .47 EL84/ :ICY 5 6AF,I 1.98 6CO3 ..90 6HS8 ..79 84 U8 ..88 í2F5 .1.50 186X ..81 6605 1.65 3n6 í.4A 6ÁG5 ..68 GCRG .58 6X26 ..56 SAWS ..91 12F8 ..64 19656 ..75 EZ80/ AUDIO plans for constructing tape degausser cross- . 88X8 ..87 12F46 . .77 19 .. .85 . 71)1 .,67 6ÁG7 1.35 6056 .55 6X6 .56 6V4 ..95 relay $1.00. Jef Enterprises, P.O. 3:+1(6 ..SR 66:X4 ..79 6057 ..67 634 2.95 8805 ..61 12FK6 ..48 19866 .85 GZ34/ over network speaker 3DT6 ..52I 64H6 1.05 6CÚ5 ..56 6J86 ..98 8CG7 ..61 12FM6 . 48 19866 1.35 5484 1.75 Box 968B, Los Altos, Calif. NO TERMS: Mi imum order $5.00 exclusive of postage. Remit full price plus postag ABOVE PRICES we have one of the largest C.O.D. The above list does not reflect our entire stock as SUBJECT TO CHANGE quotation. selections of SPECIAL PURPOSE, BROADCAST & TV TUBES in the U.S. Write for WITHOUT NOTICE PERSONALS

ESTABLISHED 1920 SEND FOR COMPLETE ONLY $35.92 Monthly repays $800.00 (thirty payments). UNITED RADIO CO BOX 1000R, NEWARK, N.J. PARTS CATALOG Borrow $100- $1,000 entirely by airmail. Write today. Bankers Investment Company, 92 -A, Hutchinson, Kansas 67501. CIRCLE NO. 233 ON READER SERVICE PAGE

MUSIC PATENTS HYPNOTISM

ROEMS Wanted for songs and records. Send poems. INVENTIONS: Ideas developed for Cash Royalty sales. FREE Hypnotism, Self- Hypnosis, Sleep Learning Cat - 3rown Music. 49 -RB West 32, New York 1. Raymond Lee, 1606G Bush Building, New York City 36. alog! Drawer H400, Ruidoso, New Mexico 88345.

92 ELECTRONICS WORLD

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Pofe, 1716 -EW Northfield, Muncie, Indiana. 35 2.25 2.50 2.85 1.40 In handsome calf grain carry. 100 3.75 4.60 5.65 8.00 SOUND EFFECTS ing holster that clips on belt. -Quarter -track stereophonic, $4.25. 240 16.50 24.50 Query Query Unique gift! SOUNTAGE; Box 176, N.Y. "SCR SILICON CONTROLLED RECTIFIERS! Equipped with powerful magnet. Levittown, SPORTSMAN 11756. PRV 7A I6Á 25A PRY 7A 168 25A 25 .50 .es 1.20 250 2.40 2.75 3.20 50 .85 1.20 1.40 300 2.70 3.20 3.60 NEW! Tape automatic shutoff $3.95. Also large reel 100 1.35 1.80 2.20 400 3.25 3.60 4.25 adapters. Leroi Electronics, Marengo, III. 60152. 150 1.65 2.20 2.70 500 4.00 4.5 4.90 CT and POWERFUL! 200 1.85 2.50 3.00 600 4.50 5.15 5.65 Silicon Diodes 366 amp Studs Untested 12 for Si COMPA beam Class Diodes 11434 48 60 64 Untested 20 tor SI a brilliant EQUIPMENT TERMS: Money each Guarantee! Throw Our 18111 year. $2 Min. order F.O.B. N.Y.C. Add shpt Charges to 95 "TAB" Or for C.O.D. 25n Dep. Puces shown subject to change. light up HEAR 47 Aircraft. Tower Emergencies, weather. Portable 111 -wQ Liberty St.. N. Y. 6, N. Y. 200 yards. e 9 Transistor AM -FM -VHF Aircraft receiver. Beautiful Seed Tic- Phone: REcter 2.6245 for Cattalo(' Black with Gold Trim. $26.50. Free Details. Transco, CIRCLE NO. 225 ON READER SERVICE PAGE ONLY EACH Box 13482, North County Station, St. Louis 38, Mo. WALKIE- TALKIES -Communicate with friends, business GET associates, up to 5 miles. Service, construction, busi- IT from GOODHEART: ness, boating, hunting, Fire Dept., Police. Free De- ALLBAND SSO RCVR BARGAIN: ii alo- :I1,:. 1: 1, tails, Sheirr Electronics Lab, Dept. G, 1182 Kenniston .5I:It.7. 13 ,,: \'c l \\. ]I, g: "üPkr.. 2 onttinll ke 1! 1 Ave., Los ',moor: 1:: Angeles, Calif. 90019 h e 1 , r r , , 1 : I l I ' ` rimier.. .to , d i, :- o d,.r.n a \ . I., . Pvr .I,1\-. , '11:In,111onk. oih,.,- ,.,a. LABORATORY Test Equipment Bought, Sold, Swapped. h,,ae, ,` a],ge,1, elean. g,l,l, r"I, .\ng. 1u: 149.50 Hewlett Packard, Tektronix, General Radio, I... Etc. Large r do cv 1rv .p.v. ready to u.c 179.50 Inventory. Special Sale. Hewlett Packard VTVM 400A \ .\,1,1 ._11 for ..It Product 11ete1/1"r in.1al1,.,i.I $65.00. Rex -84 Cortlandt St., N.Y. TIME PAY PLAN: Aloe Purcl,.c totaling 100/ :1,:11.1111 or toot, . down 1u n11nt only. . 0 FREE electronics catalog. Tremendous bargains. Elec- ARC-5 trolabs, Department C -109E, Hewlett, New York 11557. Q-5'ef It.,r 111,1-5511 Ice 83 ke IY'.. t'.e -nI , for a ,nee other l'IO.kld ,: ,.;,,,e:;lot.';"'r of ,,it. ,L ,I:. n :,1e ,. Lnnb. !, ii,. ..,tR.. 14,95 MOTORIST \i,r .n for .s,,-:,-,i,no ele,-teer unit. , HIGH With Auto Charge Adapter for recharging in FIDELITY AN APR-4 RECEIVING SET: Time :tt to Irmo t In- . 'r..i,r. IS. It .IeH- s: plug: h:u,tl auto cigarette lighter outlet and powerful ,"ok: checked. grll OK. fo11 I.ns Angele... 179.50 Alnico magnet for attaching under dash. Id1 titl, for 7'\-1t1. 97 3.2201, m,: a,1,1 8125 for LOW. LOW quotes: all components and recorders. Hi -Fi, T\.31. 117344111 , ad,1 titi, for A\I VD , Roslyn 9. Penna. o, 1b, , d11 rCpwr -p1\': :old 81^_3 for RIO' . .rn:nlapL,vr : 1,,,,,,-n . , c c , , ' . WARRANTY HI -FI Components. Tape Recorders. at guaranteed LM FREQ. METER 125 lie io ! Ill, i 11,11131. hetcr. FULLY WARRANTEEO -We Will Not Be Undersold" prices. 15-day money -back il. A ,al ''\\I. avettraev FOR i' :ii ,ali l'l';dt'''.:i,e,l,,.,i'r 11111:51.50 ONE YEAR (except I , i . ' , I : : i , r , d' , l . guarantee. Two i l u 1..\ -year warranty. No Catalog. Quotations , 18 . ii End forever the dead for bulb and Iona If I. Free. Hi- Fidelity Center, 1797 (L) 1st Avenue, N.Y., \ LII.¢ J,ft' 1\I -I,1,-a- 'plug.. d:n:,. or t111 for END. battery problem just any defect develops un- i, . ,'- m I H Parl.. dat:I. dir 1n1.1 d.c normal use of this N.Y. 10028 when you TS 423 UP, _ .1110 ,i :r I;e:1tT.i'11 F.11 1. MUST have product within one par HI -FI components, tape recorders, sleep learn equip- .l Y 1 i,,ìtok tn,P1,.111ent light. PAYS FOR ITSELF horn the data of its put- .. St h,rk ,iru,l`i'lo ment. tapes. Unusual Values. Free Catalog. Dressner, .:a' 111ì ' r in a chow, return Ma proC- - appr nh IT relatively short time , 1:,.111,1:1--"in.trion..'1;,rr uct to the manufacturer 1523 Jericho Turnpike, New Hyde Park 10, N.Y. .;I: ,1ai.a.";'.':'.e'199.50 because it .,,d:,-,I. Ini , u,l lO11 I.n. .In_ and the necessary repairs FREE! Send for money saving stereo catalog 4E12W NEVER NEEDS or rapbcunant of parts 7F1(71t0N1% SCOPES '.,,rd ,1K A ,",ge"11.. 1e.1,.: and lowest quotations 3.1 tt will be nude AT NO on your individual component. BATTERIES! . iñ,.9, d,.n,,ú,,31'.' . 395.00 CHARGE TO YOU other tape recorder or system requirements. Electronic --:514AD .. .i. . ,. \'ide. 11,1:,, i.:n, ...450-00 than a handling and Values. Inc. 200 West 20th Street, N.Y., N.Y. Both come handsomely 10011. -513: III' a,r,.l. i"'r 211 m,' pa....495.00 shipping chards of 50c. I"Il.. GIFT BOXED. FREE- -S1.00 Value "Miracle" Record cleaning cloth =3150 :i' .r"n .old... ,,,. .lo' .o,.,.P...395.00 a n,th every quotation on HIFI EQUIPMENT. Our "ROCK =512 ,.oP. add. ser -.low .,,..11.. , . 450.00 25240 A . . BOTTOM" prices on NAME BRAND amplifiers- tuners- 'I'\' .tatlnn 1:,n,1.11 1'11/0.,. . . 550.00 CONSUMER SERVICE COMPANY taperecorders -speakers- FRANCHISED -59 YEARS IN 7531 -'It" 1,r.aolp: mood ,",n,,. 695.00 160 Mercer Street, New York, N. Y. 10012 I BUSINESS. Write for this month's specials -NOW! HEWLETTPACKARD GOODIES gib! 11K .s books: ' -1000 ,,11.11Y too F'11.1, ,I111.111 . .295.00 Enclosed is $__ _. Please send the following: II Rabsons 57th St., Inc., Dept. 569, 119 W. 57th St., ,202A I.o,eYre11. Fuor, " 295.00 v9:1 York, New York -4104 a11-l'ori,o.e \'T\'.\I " 7 w 1i¡¡I50.00 Sportsman __ Motorist at $12.95 ea. plus 10019. =52OA l,.r:eir .:der rll.11,'ge.ill'11i'n,in .75 ea. for postage and handling. (N. Y. C. resi- A. li .1::"11 T,' ' a,i,i.,1. 1:" , , 295.00 -4000 . dents please In.IO,1. .21n1.5 d,. add 4% sales tax). Foreign orders .1.. rt'v'r". 1,.,.. . 'dr. 51511 ,.I $1.15 additional. io,r31'11 . I"a . . 1 " , full . :,le. :\. I,r 265.00 PRINTING =6504 11.1/i1. 111 ,r t11'111 1,, 295.00 Fol' 1.,\. ,.,Ir:ln"n,sI,.,., 11: Name "th,.r Itr,,gr.. I"Itage , ldrr. n11 .rit hat:o'rr+n,.. Sel/t. a11. FO, (PLE,,aE PRINT) 1.1\: \1,l.l'\,;1:'IIF,:I'1.\rim, sec ilet. a,1, Olt I\'1:111 1965 DESK Calendars, your 1'1111 We Address name, call, address, 1,\T\! ila,,. the ,'id11 i,nent o, 111 1111111 I- ,oa1r,ial' of th, ".n,n, m,11,I'.s.1 Three $1.00. Morgan Printing, 443 Euclid, Akron, Ohio '.." 44307-3. I City State Zip Code BOOK PRINTING. Lowest cost. Paperbacks or hard cov- R. E. GOODHEART CO. INC. Sorry -No charges or C.O.D orders. Ew 124 ers. Catalog free. Addams Printers, 30 W. Washington, Bolt 1220-A, Beverly Hills, Calif. 90213 ....m...__..1 Chicago, Ill. 60602. Manes: Am 213, office 272-57077tsssagsa 27141242 December, 1964 . 243 ON READER SERVICE PAGE 93

www.americanradiohistory.com Rectifiers & Transistors 750 ma. Silicon Diodes Silicon Power Diode PHOTOGRAPHS 3 amps. BARGAINS "Epoxy" or "Top Hat" PIV PIV PIV PIV a 50 50 600 250 25 60 300 300 PHOTOGRAPHERS ATTENTION! Photographs and trans- Write for copy of our 100 70 *700 300 50 80 400 350 parencies wanted -To $500.00 each. Valuable infor- 200 100 *800 380 100 140 500 450 Bargain Brochure mation -Free. Write Intraphoto -EW, Box 74607, Hol- Complete 400 150 *900 480 150 180 600 550 500 200 *Top hat only 200 250 All tests lywood 90004. I Collins SKW, 10 Chan, Autotune Full Leads. rested. Gua anteed. American made. XMTR A -1, A -2, A -3 SLow 10 watt Silicon Zener studs, 5v.- 100v., voltage $1.25 ea. Boonton '.070 Un;vertcr $ 300.00 any Collins It- 388/51J3 Receivers P U R 10 watt Silicon diffused stud power regu- AIRCRAFT RADIO Boonton 1911A 'Q" MTR 625.00 lators & double anode clippers, 10v- Boonton 16(:A "Q" MTh $350.00 120v, any voltage $1.49 ea. 4 Rand Tuning Units for AI'It -4 Re ceivers, Slide Rule Dial, Type CV-253, 1 Watt Zener Diode 6v -200v 750 ea. WANTED Aircraft Radio Sets -Collins: 51R3.51X -51Y 38- 1(1í11I M(' Like New 189.50 Hi- Voltage -Silicon epoxy diode, 21/2 "x3/8"x1/2", -51V -51Z, Bendix: T -21; R21; DFA -70; RA -18C; MK -7; Low Frequency Revr.IIBL -2 14 EC -600 EC 175.00 holes, 8" glass insulated leads, original RI' 233A Audio Generator ...... 375.00 mounting GSA -1, Test Sets: ARC- Boonton -Collins- Hewlett- factory package. HP 61188 Sig. Gen. 10MC.- 400Me. like new 595.00 Packard. Highest prices paid. J. Lee, Box 105, New G.R. Unit ()seill's 1211B 5 to 50me. New . 210.00 HOFFMAN -3000 piv -200 ma. (orig. cost HP 6511AR Sig. Gen. 1()cy to some. Excellent 300.00 ea. Haven, Conn. HP 4755 Tuneable Blolmeler, New 99.00 HP 212A Puise Generator, Excellent 325.00 HÓ FMAN-6000 piv (3000 piv tap)-200$1'95 HP 205 AG Audio Generator. Excellent 295.00 $30.00) $4.50 ea. TS 418 /U Sig. Gen. 4111110e to 1OOme. ma. (orig. cost Like new ...... 495.00 Thermistor, glass bead, 1200 ohms, PHOTOGRAPHY -FILM, Measurements Corp. 31 Intermodttiation 600 °F, factory packed by Victory Engr., Monitor. New 150,00 EQUIPMENT, SERVICES Empire Devices Broadband X -tel mixer type 32A3, long leads 2 for $1.00 CM-107C, 1120me to 17110mc. Excel- 20 Watt Germanium lent 90.00 Wavegudes (internal heat sink) Hl' X370(', New 30.00 2n1038 6 for $1.00 2n1042 4 for $1.00 MEDICAL FILM -Adults only-"Childbirth" one reel, HP S370(1, New ...... 62.50 Close out I(I11 ft of 156.11 A /U, PI. -259 each 2n1039 4 for 1.00 2n1043 3 for $1.00 8mm $7.50; 16mm $14.95. International W, Greenvale, end. New 3,50 2n1040 3for 1.00 2n1044 2for$1.00 Long Island, New York. SPECIAL PItD 11(10A :3db. Attenuator 9.95 1.00 2n1045 700 I'RD 390 Adaptor, NEW 22.50 2n1041 2for PRD 130E 6db. Attenuator 25.00 150 Watt Germanium Hi -Freq Power SCIENCE Bargains- Request Free Giant Catalog 'ICJ" AN /URM 14 Mike Simulator Q 100 volts, 10 amp 2n1046 $1.50 ea. AN /UEH -1 lull ke Dig ('minter 290.00 ea. -148 pages -Astronomical Telescopes, Microscopes, AN /URM 25 Jig. Gen IllEr -5051e. Q 100 volts, 20 amp 2n1907 $1.95 HP 6830 2 4 EMC Sweep Oscillator 1800.00 150 Watt Germanium Power Lenses, Binoculars, Kits, Parts, War surplus bargains. 1'S -47A /APR Sig Generator 75.00 2n457 800 Scientific Co., Barrington, New Jersey. TS -147 /D x Band Test Set 675.00 2x250 3/$1.00 Edmund BC -1032B l'anadaptor 5.25 me IF 125.00 2n102 900 Ballentine 3(10 VTVM 99.00 2n251 2/$1.00 Hewlett Packard 4306 lower Mtr. 120.00 TS- 26811/ U Extol Rectifier Test Set 17.50 2n456 700 2x1022 $1.25 TS- 375A/1.1 VTVM 65.00 2n702- 100mc, Silicon 400, 2n703- 150mc, Sili- INVENTIONS WANTED TS -917 Analyzer for TTI' 175.00 TMC Type FER Receiver Q con -600 Measurements 811 Sig Gen. Q Germanium switching transistors, 150 mw, long Dumont 2560 .scopes 90.00 help idea or Dumont 32 t Scopes 245.00 leads, tested 6 pnp-$1.00, 6 npn -$1.00 INVENTORS. We will develop, sell your SP-Iilltl JX -540 Ec- 54mc /s 450.00 flat case, short printed Job 500- 3Lmc /s Q Small-signal transistors, invention, patented or unpatented. Our national manu- R390 Digital 320.00 leads, new assorted, tested 15/$1.00 chit -1n 5 to 40Ó2c /s circuit board facturer clients are urgently seeking new items for out- Tektronix 514AD 375.00 Nickel- Cadmium Battery -61/2 6 "x2 "x1/2 160.00 oz.- "- right cash sale or royalties. Financial assistance avail- HP 4000 VTVM 210.00 5 amp -hrs. $1.25 ea. 11P 25B For free informa- HP 50011 Freq Mte. 150.00 able. 10 years proven performance. (len. 95.00 SILICON CONTROLLED RECTIFIERS Brokerage, HP 201111 Audio 150.00 PRO 7 16 25 pR o 7 16 25 tion, write Dept. 42, Wall Street Invention Bird 63A VHF Waltmeter amp amp 79 Wall Street, New York 5, N.Y. 25 a.3Ó.600 .90 200 1 .50 2.10 2.60 50 .60 .90 1.10 300 2.30 2.70 3.10 100 1.00 1.50 1.80 400 2.70 3.10 3.85 150 1.30 1.80 2.30 500 3.45 3.95 4.45 4178 Park Ave. ALL TESTS STUD TYPE 600 3.70 4.70 4.90 SPACE Money back guarantee. $2.00 min. order, Include SITUATIONS WANTED Bronx, N. Y. Postage. Catalogue 25g. Electronic Components Co. ELECTRONICS (212) CY 9 -0300 Box 2902 Baton Rouge, La. 70821 GLASSBLOWER experience on TV tube refill. Write Box elocr r NIL 221 ON READER SERVICE PAGE CIRCLE NO. 13 8 ON READER SERVICE PAGE 584, Crestview, Fla.

CLASSIFIED ADVERTISING ORDER FORM 1965 COMMUNICATIONS HANDBOOK Please refer to heading on first page of this section for complete data concerning terms, frequency discounts, closing dates, etc. Spring 1965 ELECTRONIC EXPERIMENTER'S HANDBOOK

1 2 3 4 5 Fall 1965 ELECTRONIC EXPERIMENTER'S HANDBOOK 6 7 8 9 10

THE BIGGEST CLASSIFIED ADVERTISING 11 12 13 14 15 COMBINATION BUY OF THE YEAR IS NOW OPEN TO YOU! 16 17 18 19 20 Don't Miss These Three Great Oppor- Your Ad To A Buy- 24 25 tunities To Expose 21 22 23 ing Audience That Will Respond For An Entire Year. 26 27 28 29 30

1965 Communications Handbook $0.75 Word 35 31 32 33 34 Spring 1965 Elec. Exp. Handbook 0.75 Word Fall 1965 Elec. Exp. Handbook 0.75 Word S @ .35 Reader Rate 1 Rate for All 1.55 Word Words @ .60 Commercial Rate) $ Special Combination - Combination Rate for Communications Insert time(s) Total Enclosed $ and Spring Elec. Exp. Handbooks ONLY $1.10 Word NAME

CLOSING DATE FOR COMBINATION RATES: ADDRESS November 25, 1964

CITY ZONE STATE Send Order and Payment Today to:

Martin Lincoln, Classified Adv. Manager SIGNATURE Ziff -Davis Publishing Company WORD COUNT: Include name and address. Name of city (Des Moines) or of state (New York) counts as one One Park Avenue Zone or Zip Code numbers not counted. (Publisher reserves right to omit Zip Code if space does word each. New York, New York 10016 not permit.) Count each abbreviation, initial, single figure or group of figures or letters as a word. Symbols such as 35mm, COD, PO, AC, etc., count as one word. Hyphenated words count as two words. EW -1264

94 ELECTRONICS WORLD

www.americanradiohistory.com SILICON RECTIFIER SALE WANTED GREGORY ELECTRONICS RECONDITIONED IMMEDIATE DELIVERY FM QUICKSILVER. Platinum. Silver, Gold. Ores Analyzed. FULLY GUAR'NT'D NEWEST TYPE Free Circular. Mercury Terminal. Norwood, Mass. 2 -WAY RADIO SAVINGS AMERICAN MADE FULLY TESTED THIS IS A PARTIAL LIST CASH Paid! Sell your surplus electronic tubes. Want - unused. Clean radio and TV receiving, transmitting WRITE FOR NEW FALL '64 750 MA- SILICON "TOP -HAT" DIODES special purpose. Magnetrons. Klystrons, broadcast E- X- P- A- N -D -E -D CATALOG LOW LEAKAGE FULL LEAD LENGTH types. Want military and commercial lab test equip- PIV /RMS PIV /RMS PIV /RMS PIV, RMS ment. Want commercial Ham Receivers and 50/35 100/70 200/140 300/210 Trans- Extra Special Purchase .05 a .09 ea .12 ea .16 ea mitters. For a Fair Deal write: Barry Electronics, 512 PIV /RMS PIV RMS PIV /RMS PIV RMS Broadway, New York, New York 10012 (Walker 5- 7000). Reconditioned General Electric 400/260 500 /350 600/420 700/490 .20 ea .24 ea .32 ea .40 ea URGENT, NEED IMMEDIATELY. Very high prices paid. PIV RMS PIV,RMS PIV RMS PIV,RMS 800/560 900/630 1000/700 1100/770 Freight prepaid. AN GRC; PRC; APR; ARC; ALT; URM: .48 ea .55 ea .70 ea .75 ea UPM; TSWe also buy all military and commercial Voice Commander test, radar, and communication equipment. Personal FM ALL TESTS AC A DC & FWD & LOAD CALL COL- LECT. IT COSTS Transmitter- The General SILICON POWER DIODE STUDS YOU NOTHING TO HEAR OUR HIGH Receiver Electric VOICE D.C. 50 PIV 100 PIV 150 PIV 200 PIV OFFER. SPACE ELECTRONICS, 4178 PARK AVENUE, 132 to 172 MC. 1 W COMMANDER AMPS 35 RMS 70 RMS 105 RMS 140 RMS BRONX, N.Y. (212) CY 9 -0300. I Personal Transmit- ter- Receiver is J .12 .18 .22 .30 (WANTED) CASH Given: Used Electronic Parts and a 12 .45 .65 .75 .90 high performance, .90 1.15 1.50 1.70 Equipment. Radio Research, P.O. Box 311, Kenmore - i 1.60 1.90 2.30 2.80 Square, Boston 15, Mass. completely self -con- 11111 1.75 2.15 2.55 3.15 tained two -way FM D.C. 300 PIV 400 PIV 500 PIV 600 PIV Radio. Extremely AMPS 210 RMS 280 RMS 350 RMS 450 RMS GOVERNMENT ___,_..,__a__,._ , compact and light- SURPLUS `- weight, VOICE 8 .40 .45 .55 .65 the 1. 1.10 1.35 1.50 1.70 COMMANDER 2.35 2.55 3.00 3.50 is sim- 4.20 ple to operate and 3.50 5.25 7.00 JEEPS $62.50, Transmitters $6.18, Typewriters ltnl 3.75 4.60 5.65 8.00 - - easily hand carried. - $4.15. Walkie- Talkies, Oscilloscopes, Multimeters. "SCR" SILICON CONTROLLED RECTIFIERS "SCR" Typical Surplus Prices. Exciting Details Free. Enter- Except for the final 7 16 25 7 16 25 PRV AMP AMP AMP PRV AMP AMP AMP prises, Box 402 -B8, Jamaica 30, N.Y. stages of the transmitter, the VOICE -'.11I 2.30 2.65 3.10 JEEPS $64.50 Boats $6.18 ". .50 .85 1.20 ...... Typewriters $4.15 COMMANDER - .85 1.20 1.40 :11111 2.60 3.00 3.40 is com- 1.35 1.80 2.20 Ilnl 3.00 3.40 4.15 . Airplanes, Electronics Equipment, 100,000 Bar- pletely transistor- l'. 1.60 2.10 2.65 51111 3.75 4.25 4.75 gains Typically like These Direct From Government in _1111 1.75 2.40 2.90 Gull 4.00 5.00 5.25 ized. Your Area. For Complete Directory and Surplus Cata- log Send Only $1.00. Surplus Service, Box 820 -K, SPECIALS Holland, Michigan.

240 Amp 200 Piv $ 50 MUSICAL INSTRUMENTS Sil. Power Rect 1 ea.

ACCORDIONS, GUITARS, BAND INSTRUMENTS! Save 1/2. 2 Am 1000 Piv Famous makes, free home trial. Easy terms. Trades. p 5C Free Discount catalogs. Mention instrument. Interna- PRICE, including Brand New rechargeable Nickel Sil. Power Rect ea. tional Music Mart, Dept. EW, 5535 Belmont, Chicago, Cadmium Battery Pack 10 for $1.00 MAGAZINES 100 Different Asst $150 $178 Ife crystals and tuning is Precision Resistors d sir d. add '40.00. ELECTRON is A Brand New Electronics Hobbyist 1/2 -1.2 Watt 1/2 % -1% Tol. Magazine. Free Sample Copy, Electron, Box 796, We also have the Montreal, Canada. proper chargers for these units, GE Type IN34 Diode .07 ea $500 Model `4EP27A10, 100 for BOOKS Price: $18. If additional nickel Cadmium Battery Type IN91 Packs are required. Germanium Diode $100 AUTHORS! Learn how to have your book published, they are available at a price I 10 for promoted, distributed. FREE booklet "ZD," Vantage, 525.00 :ch. 120 West 31 St., New York 1. Filament Transformer PUBLISH your book! Join our successful authors: pub- MOTOROLA 450 -470mc licity advertising promotion, beautiful books. All sub- T44A6, 6/12 volts, complete with all accessories, Pri -120V Sec 6.3V at 1 Amp jects invited. for free 504. Send appraisal and detailed less crystals booklet, Carlton Press, Dept. ZDL, 84 Fifth Avenue, and antenna. Money Back guarantee. $2.00 min. order. Orders N.Y.C. 11. F.O.B. NYC. Include check or money order. Shpg. charges plus. C.O.D. orders 25 °0 down. 1,000,000 BOOKS! Bargains! Catalog -dime. Treas- ureSite, 6990 Aberdeen, Upper Darby, Pa. 19082. $108 Warren Electronic Components TECHNICAL manuals for surplus electronics. Stamp for list. Books, Box 184, Riverdale, Md. 230 MERCER ST. N.Y. 10012 N.Y. OR -3 -2620 BOOKS 2000 Subjects Catalogs 104. Myers Book Serv- Same unit less accessories. $78 ice, Marquand, Mo. 63655. T44A6A, 6/12 volts, complete with all CIRCLE NO. 259 ON READER SERVICE PAGE accessories, less crystals and antenna. $128 Same unit less accessories. $98 COINS RCA 25 -54mc CMF40 6 12v 40 watts. Vibrator power supply. Fully nar- TWENTY page A27 Retail price list of USA and row banded. Canadian coins 10e. Our retail selling prices on .... Complete with ARR -2 RECEIVER r:1.2.á.. Ali- I 1I c & Con-,e 11:11:1 "I r C.E., 2 thousands of coins and coin collectors supplies. Bry- all accesso- ,r1.,c 1'ae1 >. $ 4.95 ries, less crys- L 8 N KELVIN -VARLEY PRECISION VOLT- son Incorporated. 612 -Z White, Toledo 5, Ohio. AGE DIVIDER _ (hn1. u.I Itatio tals and an- 1 n1 , 'iiii 1.:11,.:111,11n,li,.r. tenna. "5d "Ei, I,,,nic.: Wo,1,1 Fe111 Ii. I. il od million. LaI, I Heck ell 1111L 49.50 HIGH VOLTAGE PROBE Aa /11K' roe $178 1'11.51 , \ "l'\ II. 511n Meg_I II -cinU n'. Large STAMPS Quality peu be lint. fOr over 512.1111. Brand 2.95 (Same unit without accessories, $148.) R -2378 /VR MOBILE FM RECEIVER : SI1.4II5IC Same unit tuned to your frequency including brand Gv UC Vihratnr Power Supply-Easily con- new antenna, ready for installation. $218 verted 112v1)(2. u,.ed. Good. with S1, FREE! 25 Egypt, 100 handling. Approvals, Bellet P -E -G, 26.95 Hazel Park, Michigan 48030. We Buy Late Model Equipment for Cash T- 19361i /VRC FM MOBILE XMTR 211- 41,511' -Write; Wire or Phone! WSv I1C dynamotor. Easily co verted to I/M. ith 7 lohe- ,. cheinatir.111 -.ed. Good. 12.95 Gift (GON SEND MONEY ORDER OR (HECK WITH ORDER MIN. $2.50 GREGORY PLEASE INCLUDE POSTAGE -Excess promptly refunded. HELP WANTED MINIMUM C.O.D. ORDER $10.00 with 25% DEPOSIT Er ELECTRONICS WRITE FOR BUL. =41. LOADS OF BARGAINS ,1FrAO CORPORATION R. W. ELECTRONICS, INC. EARN Extra money selling advertising book matches. 2430 So. Michigan Ave. Dent. Free Samples furnished. Matchcorp, Dept. MD -124, 249 Rt. 46 Phone 773 -7550 Chicago. Illinois 1273 60616 Phone 225 -1281 Chicago 32, III. Saddle Brook, N.J. Area Code 201 CIRCLE NO. 185 ON READER SERVICE December, PAGE 1964 95

www.americanradiohistory.com FREE Song "Hit" copy. Postcard: Nordyke Publishers, NOW ! ! ! LOW COST AC POWER IN YOUR CAR ! ! 6000 -3 Sunset, Hollywood, Calif. 90028. 12 V DC to 115 V AC (50 W) TRANSISTORIZED POWER SUPPLY KIT REAL ESTATE CIGARETTES -Makes 20 plain or filter -tip for 9ç. Fac- $9.95 per Kit tory -Fresh pipe tobaccos. Mild tropical flavored Philip- w 'Instructions, schematic. etc. has many uses. easy pine cigars. Facts free. Moberly, Box 805, Owensboro, to wire. Approx. size of alum. box 3X3X5" (Factory WIN Government Oil Leases, Opportunities for Se- wired; ready to $16.95 ea.) Kentucky. Complete use- wealth. Mineral (Not rec. for phono) curity Enterprises, 383A Elsie Street, San Francisco, Calif. 94110. WINEMAKERS: Free catalog of equipment. Semplex, SILICON COMPANION Box 7208, Minneapolis, Minn. 55412. CONT. RECT. RECTIFIERS FLORIDA Water Wonderland -Homesites, Cottagesites, TESTED Mobilesites, Established area. $390 full price, $5.00 7 25 3/4 I1'2 2 PRV Amp Amp Amp Amp Amp month. Swimming, fishing, boating. Write, Lake Weir, BUSINESS OPPORTUNITIES 70 .90 1.90 .20 .30 38be, Silver Springs, Fla. Ad 6 -1070 (F -1) a) 140 1.30 2.25 .25 .35 -.40 200 1.50 2.40 .30 .40 .45 250 1.90 2.60 IT 300 2.15 2.85 - -.45 -.50 350 2.40 3.10 - EDUCATIONAL INVESTIGATE Accidents -Earn $750 to $1,000 monthly. BB 400 2.75 .45 .50 .55 Men urgently needed. Car furnished. Business ex- -gz 450 3.10 - OPPORTUNITIES 500 - .55- -.60 -.65 penses paid. No selling. No college education nec- e 600 3.85 .60 .65 .72 essary. Pick own job location. Investigate full time. 700 - - .70 .75 .85 LEARN While Asleep, hypnotize with your recorder, 800 .77 .05 .95 Or earn $6.44 hour spare time. Write for Free Litera- SCRs 900 - - .85 1.00 1.10 phonograph. Astonishing details, sensational catalog 1.20 1.25 ture. No obligation. Universal, CZ -12, 6801 Hillcrest, 1000 - - .95 free! Sleep- Learning Association, Box 24 -ZD, Olympia, Dallas 5, Texas. METERS Washington. ROUND I Made $40,000.00 Year by Mail Order! Helped others SQUARE LEARN while asleep. Remarkable, scientific. 92% ef- 1f/' make money! Start with $10.00 -Free Proof. Torrey, 0 -200 VAC .. .$4.49 ea. fective. Details free. ASR Foundation, Box 721, Dept. O -IMA $2.95 ea. "S" meter 0 -9 53.75 ea. Box 3566 -N, Oklahoma City 6, Oklahoma. 0 -2MA $2.95 ea. 0.200 MA DC..54.25 ea. e.g., Lexington, Kentucky. 0-100 MV $2.95 ea. 0.200 MMA ...$4.95 ea. 0 -500 MMA $2.95 ea. 0.100 MMA ..55.25 ea. AMAZING Mail Order Profits using proven methods. 0 ea. -100 MMA $3.95 0 -1 MA (Arbitrary. Research, 3207 -H Southern Hills, Springfield, Mo. q Scale) $3.95 ea. AC Volts 0 -2; 3: 5: 10: EMPLOYMENT INFORMATION HOW And Where to Raise Capital. Details Free. Finan- 25: or SO 52.75 ea. 0 -150 VAC 3" cial, Box 785 -H, Springfield, Mo. 65801. DC -MA 0 -250. 150 Rd. $4.95 ea. or 100 $4.95 ea. O -1 MA (Arbitrary Scale) $3.95 ea. FOREIGN- U.S.A. Hot listings. All -year jobs now hir- HIGHLY WEEKLY EARNINGS! Address -mail letters fea- AC MA 0.150 53.00 ea. VDC DC Volts 0 -25 0-150 Weston ing. Stamped re- turing real merchandise. Get $10 with every (dual scale) .14.95 ea. Transportation. Family relocation. order - 200.300 or 500 $4.95 ea. 0 -200 VDC . . $4.75 ea, turnable envelope. Global, Box 286 -W, Oroville, Calif. keep $8 profit. Supplies furnished. Free particulars. 0 -20 $3.95 ea. 3 Modern Box 0.54 AC (marked FOREIGN Employment. Construction, other work proj- Merchandising, 357, Oceanside, N.Y. 0 -30 VDC 55.25 ea. 0 -550) $3.95 ea. 0.5 MA DC. $3.95 err. 0.75 VDC $3.95 ea. ects. Good paying overseas jobs with extras, travel FREE REPORT: "609 Unusual, Successful Businesses." expenses. Write only: Foreign Service Bureau, Dept. D, Box 122 -ZDA, Wheeling, Ill. MONTHLY SPECIALS Bradenton Beach, Florida. Solenoid Guardian No. 16AC 115 VAC -2 Ib. pull SELL CB Equipment -Dealerships available to aggres- 1.79 ea. 12 for 20.00 FOREIGN U.S. employment, Big construction projects. sive people who can sell Citizens Band Radio full or Spectrum Analyzer Vectron SA -20 w/s Band Plug -In Model --20 -S ...... $225.00 All trades. Salaries up to $1,600 monthly with travel part time. Knox Electronic, Dept. 194, Galesburg, Dumont .x.322 Scope dual beam DC or AC Coupled excellent condition with manual $369.00 expenses, extras. Write only: Foreign U.S. Employment Ill. 61401. SCR 70PRV -7 Amps. tested $75/100 Bureau, Dept. D -8, The State Building, Portland, Maine. Switch DPST Rust proof 6A -125V new ..12 for $4.50 MONEYMAKING Mailorder opportunities. Details free. Germanium Diodes.. .Computer type-$8./100 Micro Switches V3 -1 SPOT 4/52.19 Litton, P.O. Box 33ZD, Randallston, Md. Micro Switches 1SM1 SPOT 4/1.75 FREE Book "990 Successful, Little -Known Businesses." Transformer 110V PRI 1100 VCT -400 MA ..3.95 MISCELLANEOUS ASSORTED RELAYS -QUANTITIES Work home! Plymouth -717P, Brooklyn 4, New York. WRITE FOR PRICES. SAVE $200 to $2,000 on European automobiles deliv- All Shipments FOB NYC ered at low, low factory tax-free prices by using our DETECTIVES direct shipment plan. Delivery guaranteed, references ADVANCE ELECTRONICS available. Tourist and Military deliveries available in 2 79 Cortlandt St., New York 7, N.Y. RE -0270 Europe. Information on all models and makes Eurauto, DETECTIVE Opportunities. Experience unnecessary. CIRCLE NO. 152 ON READER SERVICE PAGE Postbus 333, Rotterdam, Holland. Write, Wazgner, 125 W. 86th, New York 10024. One Year 21 PICTURE p TUBES OF THE WORLD'S FINEST utual Conductance Lab tested Arr,gear. Indr..dually.ed.ed. Brand. (Par GOVT. SURPLUS and Cote Oared 0u1ä Deyost1 sOuatd COB or Sena Bud IIhtI w t, ELECTRONIC BARGAINS w used me se m order maned TELEPHONE -TELETYPE -TELEGRAPH: 0Z4 6.576 6C 1: EH TUBE finest ELECTRONIC CLEANER Model 14 AT Teletype Used $69.95 IB3 6A T8 6C1/ 6E5 6sH7 LW I:HLr, Paper Tape: 3/e" 900 Ft Roll: 250 -30 f/$3 -60 f /$5 le5 6A04 6CG7 6146 6517 6W6 l.br' CARTONS Telegraph Repeater WE- 61824A New: 34.95 113 6ÁU5 6CG8 615 6587 6%4 I:C5 all purpose New: 12.95 IL4 6A06 6CM7 616 6507 6%5 TP7 Portable Repeater IAS ELECTRONIC TG -30 Telegraph Repeater-Used: $14.95 New: 19.95 174 6AV6 'A7 a8 _s IL[C aOFIC TG -31 Telegraph Repeater New 16.95 104 If Noi Shipped 'B6 cleáner PE -250 Telephone Ringer Used: 4.95 1%2 64x4 8 I II (. 4 h S 12.95 -87 2:552'6 EE -8 Field Telephone Used: 'B8 BD -71 Switchboard line Used: 9.95 5ä6eV6 5í -6 5v4 606 BD -72 Switchboard -12 Line Used: 18.95 Y O U IdREt.CMI1101 6B06 rN57 333 5'5 Mag. & 40 CB lines Used: 59.50 CORNELL BD -89 Switchboard -20 564" BD -95 Switchboard -Cordless New: 24.95 .D6 648 6E1 6 0 R D E R MICROPHONES: SACO 61107 I PER T -30 Throat Microphone -Used: 3 f/$1.00 New: $ .75 6ÁC7 eels 41 T UBE 7^.577 SAGS 61356 T -45 Lip Microphone Used -Each: .75 R E I. w .2AÚ7 45 6ÁK5 61356 47 RS -38 Microphone Button only New: 1.50 100 TUSES OR MORE 6CZ3 686 65'47 12.557 CTIFIERS 6.415 6816 75 T17 Microphone Carbon Re -Cond: 6.95 606 6K7 65Q7 12BÁ6 6AN8 6C4 T -26 Microphone Carbon -Used $1.00.... New: 1.75 PER TUBE 6044 6Q7 cool 12806 77 30c 6 .505 6C6 7B T -24/M Microphone Carbon New: 4.95 6DE6 654 657 I2BE6 6.555 EC86 84 HANDSETS: 60Q6 65A7 668 128,6 and at low rices- tree list TS -9 Butterfly Switch -Used $2.95..Re -Cond: $ 3.95 Other tubes CRT's send fer TS -13 Butterfly Switch w /PL- 55/PL -68- NO SUBSTITUTIONS WITHOUT YOUR PERMISSION Used: $4.95 New: 6.95 .111Cre.6.c (N'f' 1'((111.6 rr,% an H w /PL- 55/PL -68 Used: 4.95 -22/U Butterfly Switch e D170312 Sound Powered New: 7.95 Wdh everrcler ELECTRONIC EXPERT! HEADSETS: HS -33 Headset: with chamois cushions New: $ 7.95 with rubber cushions New: 6.95 per tube HS -23 Headset: with chamois cushions New: 6.95 etwote5è. SOLDER with rubber cushions New: 5.95 Chamois Cushions only 1.50 (No Umit) from this Isst. Rubber Cushions only 1.00 RAGS 6SNI HB -7 Headband only for HS -33/23 New: 3.00 6AÚ6 616 6V6 ANBH -1 Element only, for HS -33 New: 3.00 6W4 FOR COMM CUSrOMEeS ONLY by H -63 Headset with Boom Microphone Used: 3.95 BAQ 6K6 specool orror,erneyo r ..r ,. e e,e -.l HS -30 Headset -Hearing Aid Type Used: .75 ormo g g ,oreo.oM1lobleb 1EN NEW PRACTICAL TV TANNING C CODE EQUIPMENT: Console COMPLETE RADIO FERVlclnc AND ONLY 50 Serene Used: $24.95 sen 4ASIC ELECTRONICS COURSE ONLY 11.00 TERMS: Add 3e per tube TG -34 Keyer -Code Practice Tube Tester TG -10 Keyer -Code Practice Used: 14.95 shipping. Orders under $5.00 VO -3 Code Oscillator Used: 12.95 add 3c per tube shipping MX- 333/GG Code Tape Puller New: 12.95 S3 r plus SOc handling. Canadian Blank Paper Tape: 3 /8" 900 Ft. Roll 25 ea. 30/$3.60/$5 orders add approximate postage. Send 25% deposit Address Dept. EW Prices F.O.B., Lima, O. 25% Deposit on C.O.D.'s Minimum Order $5.00 on C.0.0. orders. No C.O.D. SEND FOR BIG FREE CATALOG! orders under $5.00 or to Canada. No 24 hr. free offer FAIR RADIO SALES on personal check orders $DAY MONEY BACK OFFER' 2133 ELIDA RD Box 1105 LIMA, OHIO Dept, E W 12 4217 University Ave., San Diego , Calif. 9 2 1 0 5 CIRCLE NO. 181 ON READER SERVICE PAGE CIRCLE NO. 172 ON READER SERVICE PAGE 96 ELECTRONICS WORLD

www.americanradiohistory.com CHRISTMAS SALE ELECTRONICS WORLD DECEMBER 1964 ADVERTISERS INDEX FREE $ fl ÓÖ READER READER yv SERVICE NO. ADVERTISER PAGE NO. SERVICE NO. ADVERTISER PAGE NO. y GIFT L OF RADIO & 152 Advance Electronics 96 198 Micro Electron Tube Co. 91 TV PARTS American Institute of Milwaukee School of Engineering 58 ADD 25e for handling Engineering & Technology 82 C 1/J`f'f - -- PLUS - -- Minnesota Mining & Mfg. Co. 1 SECOND GIFT 248 Amperex Electronic Corporation THIRD COVER BOTH 'GIFTS' FREE CHOOSE $ ITEM Music Associated 58 WITH $10 ORDERS ANY 1 FREE 156 Artisan Organs 85 EVERY ITEM CARRIES RMA GUARANTEE! National Radio FACTORY Institute SECOND COVER TESTED SEMI- KON- 161 Automotive Electronics Co. 57 DUCTORS 5 -30 -MC TRANSISTORS, like 2N247, pnp Si Northridge College of 30 TRANSISTORS: audio, switching, rf untested $1' 137 Bogen Communications Division 22 Li 15 TEXAS SWITCHING TRANSISTORS, pnp -n -npn 51' Science & Engineering 75 Lf 25 TOP HAT RECTIFIERS, 750 mil untested $1 1 RHEEM 2N1613 3 -WATT 100MC 163 Burstein -Applebee Co. 88 PLANAR $1 f -1 25 GERMANIUM DIODES, 1N34, 1N48 untested $1 242 Nortronics 4 3 -50 W. TRANSISTORS, T036, untested $1 Capitol Radio Engineering _ 25 "GLASS" TINY SILICON diodes, axial, untested $1 1 l0 W. POWER Institute, The 5 258 NuTone, Inc. 83 -10 TRANSISTORS, T03, untested -51 YULETIDE TRANSISTOR JUMBOPAK TRANSISTORS Channel Master Corp. 58 Oelrich Publications 82 10U Power, Audio, RF, Switching untested 250 Cleveland Institute of 203 Olson Electronics, Inc. 66 J 4 GE 2N170 TYPE TRANSISTORS, npn, rf. $1 Electronics 7 86 L] 20 WATT NPN SILICON MESA 2N1648 transistors $1 ,J 2 25 AMP SILICON STUD RECTIFIERS $1 134 Pennsylvania Fluorocarbon J 6 TRANSISTOR RADIO SET OSC-i.f.'s DRIVER, PP $1 245 Conar 78 L] 15 UPRIGHT Co., Inc. 66 SILICON DIODES, worth $40 51 L 5 GENERAL ELECTRIC 2N107 type, pnp transistors 51 25 SEMI- KON- DUCTORS, 170 Concertone 21 or equal, T03 case $1 206 Poly Paks 97 [1 5 SUN BATTERIES TO 11/4" sixes, lite sensitive $1 `] 3 CBS 20 -WATT TRANSTRS, pnp, stud, 2N1320 $1. 2 2N341 NPN 171 Concord Electronics Corporation .. 6 SILICON TRANSISTORS, 1 watt $1 RCA Electronic Components I] 15 NPN TRANSISTORS, asst. types and cases $1 and Devices FOURTH COVER 15 PNP TRANSISTORS, asst. types and cases Si 172 Cornell Electronics Co. 96 10 FAMOUS 01722 TRANSISTORS, pnp $1 3 CBS 35W TRANSISTORS, 2N1434, pnp, stud $1 174 Crown International 84 RCA Institutes, Inc. 8, 9, 10, 11 4 CK721 TRANSISTORS in new aluminum rose pnp 51 4 SUBMINIATURE 2N131 TRANSTRS, rf -if, pnp $1 2 1 TRANSITRON 1N429 ZENER REFERENCES $1 R. 178 EICO Electronic Instrument Co., W. Electronics, Inc. 95 6 ZENER DIODES, upright styles, assorted $1 r-1 Inc. 24 2 2N964 EPITAXIAL MESA, 500 MC, PNP, TO -18 -51 3 2N1264 UHF TRANSISTORS, 300 me TO 5 case 210 Rohn Manufacturing Co. 71 51 3 TEXAS 20W TRANSTRS, 2N1038, heatsink, TOS $1 177 Editors and Engineers, Ltd. 62 D 6 2N112 TYPE IF, OSC TRANSTRS, TO22 untested $1 214 Sarkes Tarzian, Inc. 14 -] 4 SYLVANIA 2N35 NPN, transistors, T022 $1 180 Electro- Voice, Inc. 20 -1 3 -1 -WATT ZENER DIODES, axial leads, 6V $1 1 -WATT 7 -85 2N424 SILICON NPN MESA transistor . S1 200 Scott, Inc., H. H 19 n 10 PHILCO UHF TRANSISTORS, like SB -100 $1 138 Electronic Components Co. 94 j 2 RHEEM 4 W. 2N497, 2N498 $1 10 2 AMP POWER RECTIFIER 217 Shure Brothers, Inc. 13 STUDS $1 181 Fair Radio Sales 96 T c PRV AMP AMP AMP 221 Space Electronics 94 TRANSITRON ti,n -2i, i. 246 Finney Company, The 16, 17 BRAND =- SCR's I 1N NEW - t. I s Stevens- Robertson Corporation .... 77 .33.i -2313, 1 - 183 G & G Radio Supply Co. 98 SILICON CONTROLLED 'i: _ s.l 224 Switchcraft, Inc. 62 RECTIFIERS a to - a. is 243 Goodheart Co. Inc., R. E. 93 Sylvania 23 MOS POPULAR $ I PARTS PAKS Grantham School of Electronics .... 60 10 RCA PHONO PLUG 'n' JACK SETS, tuners -amps .S1 i 225 "TAB" 93 60 HI -0 RESISTORS, /2, 1, 2W to 1 meg, S% too .51 184 Greenlee Tool Co. 60 i 50 (OILS 8 CHOKES, rf -if, osc, peaking, etc. $1

1 $25 RADIO 'n' TV 228 Terado Corporation SURPRISE, wide variety $1 58 10 TRANSISTOR ELECTROLYTICS, 10 to 100 mf 185 Gregory Electronics Corporation 95 51 .. 50 RADIO 8 TV KNOBS, assorted colors, styles 5 229 Texas Crystals 87 it 50 MICA CAPACITORS, to .Olmf. silvers too $ 186 Hallicrafters 68 , 30 POWER RESISTORS, to 50W, to 24 Kohms $ 10 PANEL SWITCHES, rotary, mica, slide, power $1 Tri -State College 68 1 60 TUBE SOCKETS, receptacles, audio, plugs, etc. $1 187 Heath Company ... 59, 61, 63, 65, 67 7 60 TUBULAR CONDENSERS to .5mf to 1KV Si 7 50 ONE WATTERS, 233 United Radio Co. 92 resistors, asstd. values, 5% too S1 Henshaw TV Supply 75 3- TRANSISTOR SUBMINIATURE AMPLIFIER Only 3 "x2 "x?!r" Valparaiso Technical Wired Institute 86 Printed Circuit W Transistors Instantspark 82 ' 1 INFRA -RED PARABOLIC REFLECTORS 8 FILTER .$1 252 1 INFRA Viking of Minneapolis, Inc. 12 7 -RED PHOTO DETECTOR TRANSDUCER ... .51 189 International Crystal Mfg. 4 TANSISTOR TRANSFORMERS, assorted, worth 52S $1 '-I 40 WORLD'S SMALLEST RESIST., Co., Inc. 2 259 5% too, 1 /10W .51 Warren Electronic Components 95 60 CERAMIC CONDENSERS, i discs, npo's to .05mf $1 -1 40 TEXAS PRECISION RESISTORS, assorted $1 191 Johnson Company, E. F. 81 251 Webster Manufacturing 89 7 10 Lock Transistor Transformers, asstd. Si 1 10 ELECTROLYTICS FP 8 tubulars, to 500mf $1 Kuhn Electronics 3 UTC SUBOUNCER TR'STOR TR'SFORMERS, asst. $1 86 235 Weller Electric Corp. 69 30 SPRAGUE MYLAR condensers, asst. values, volts S1 7 75 ASST. HALF WATT RESISTORS, 5/ too Si -I 35 TWO WATTERS, 194 Lafayette Radio Electronics . 72, 73, 74 237 Winegard Co. 55 resistors, 5% too Si Trusts: .p nil rhor k. m , 128 Lampkin .,r,h.r .,,LI e,r:,:r,, ',.< Laboratories, Inc. 85 238 Workman r Electronic Products, Inc. . 87 LY tr n.k Ii.. Rnterl. net 7n O _ FREE -Winter Cassified Advertising Catalog .... 91, 92, 93, 94, 95, 96 BOX AKS SO. PL OYNNFIELD, MASS. PANHING' OF THE WORLD CIRCLE NO. 206 December, ON READER SERVICE PAGE 1964 97

www.americanradiohistory.com SCR -625 MINE DETECTOR FAMOUS BC -645 TRANSCEIVER IMPORTERS EXPORTERS Complete portable outfit in erigi -$3250 - 15 Tubes 435 to 500 MC nal packing, with all accessories L Ca be nmdihed for 2.w.nv .3,14,r,.....-, of ELECTRONIC EQUIPMENT uoni Brand New rode hamband 4'n -4só I ~ Hr, mc. fixed s olio 460-170 9p fixed euÌ awhile 451,. We fi c television experi- specialize in the export mental '47ó.50o mc. 15 111r TS- 239A /UP OSCILLOSCOPE, for bench -testing all tubes (tunes :done worth Û types of radar and communications electronic of military surplus electronic more than sale Priced 4- equipment. Comprises calibrating voltage gener- 777, 4-7H7. 2-7E6, _ equipment: (IF6, 2 -955 and 1 -w E- BRAND ator, timing marker generator and trigger gen- :3113A.No coverss 46f, to NEW less power erator. 400 mc. B randnew 11C -645 with tubes $99,50 All at LOWEST PREVAILING PRICES. supply In factor.' carton. Excellent Condition Shipping weight 25 lbs. SPECIAL! $19.50$199 In addition to items shown on this page. we have PE-101C Dynamotor. 122 /2.1V input $7.95 AN /ARN -6 RADIO COMPASS DF RECEIVER 100 to in stock or can obtain for export UHF Antenna Assembly 2.45 and domestic customers, military electronic Complete Set of 10 Plugs 5.50 1750 Kc in 4 bands. Builtin vibrator power supply Control Box 2.25 for 24V DC. Complete with tubes, equipment made for World War II, Korean $29.50 War, and later. We maintain one of the SPECIAL "PACKAGE" OFFER: exc. Used BC -645 Transceiver, Dynamotor and all .,cc iiiirh-- largest stocks of Government Electronic ahoy, COMPLETE, BRAND NEW, Surplus Equipment in America! W. Stocks Last 829.50 iOC -610 TRANSMITTER 2 -8 Mc Complete Excellent Used, clean P U R IF YOU DON'T SEE WHAT YOU WANT BC -344 RECEIVER. 150 -1500 Pc., HERE- WRITE US YOUR NEEDS. WE'LL continuous tuning, 4 -band. for 115 V QUOTE ON ANY GOV'T SURPLUS EQUIP- 60 Cycle AC. Excellent used. perfect $79.50 LM FREQUENCY METER MENT YOU SEE ADVERTISED ANYWHERE. working order. complete with tubes. ii ..., hrated modulated. Heterodyne, I2.5 Ne' Write or call today for our low LOW BC -342 RECEIVER. 1.5 to 18 Mc. AC , Rr. with Calibration honk. l, . like $79.50 PRICE, and SPEEDY DELIVERY FROM Only. Like New, complete with all $79.50 LM Frequency Meter as: above, mpletely iwckeil STOCK! tubes lit. with times and less calibres- lion hook. Esc. Used.' clean $34.50 BC -348 SUPERHET RECEIVER 200 to 500 Cr All packing and shipping is made directly and 1.5 to 1800 Mc. Voice Tone, CW. Self -con- from our own warehouse in NYC to give tained dynamotor for 24 V DC. Exec. l'>011. BC -221 FREQUENCY METER you substantial savings in handling costs! Checked out $89.50 Equipped with original calibration charts. 125 Kc to AC Power Supply $14.50 20.000 Kc with Crystal check points in all ranges. Excel. Used with original Calibration Book. Crystal, and all tables. CHECKED OUT: BC -683 FM RECEIVER, 27 to 38.9 Mc , Com- Cn,nodniated Modulated ...P.U.R. $89.50 plete with all tubes. exc. used. Checked $49.50 AC power Supply for 11C221, checked out....$24.50 WE BUY FOR CASH out, in working order your surplus Military Electronic Equipment BC -221 1000 Kc Crystal Brand New $8.95 BC -603 FM RECEIVER, 35 -:d0 Mc. Complete with all BC221 FRED. METER CASE, aluminum. with volt, WRITE -WIRE -PHONE tubes. checked out. Like Nett. $49.50 : ... ,nPply. Shock mounted I:R \ \O NEW ... $2.95 Original -l' inn) . Slsoli al for :hove S 3.15 AC Power Supply for above, wired $12.95 LORAN APN -4 ARC -5 T 23 TRANSMITTER I , , l \I 'l , I 12 -Volt Mobile Dynamotor ;\ no FINE QUALITY nl Power Supply. NEW $ 5.50 I,IiVA1NO-7,1 with .512. $26.50

I 1 c NAVIGATIONAL EQUIPMENT I -2 'l' 512. U.ed. I - t c 53.95 ARC -5 R-28 RECEIVER 2 trier sm.-ibid. 1(111 to I., Determine exact geographic position of your boat Mr., i, 4 crystal channels' Complete with 10 tidies. Excellent Used $24.50 BC1206 -C BEACON RECEIVER or plane. Indicator and receiver complete with all I,ilce NEW $29.50 tubes and crystal. 195 to 420 Kc. made by Setchel - Carlson. Works on INDICATOR ID -6B /APN -4, and RECEIVER R -9B/ AN /APR -4Y FM & AM RADIO RECEIVER 24 -28 volts DC. 135 Kc. IF. APN -4, complete with tubes. Exc. Used. $69.50 High precision lab instrument, suitable for Complete with 5 tubes. Size monitoring and measuring frequency and relative NEW! APN -4A Receiver -Indicator as above, changed signal strength of signals from 38 to 4000 Mc., bs.rLIKE NEW t... $ 1 0.95 to operate same as APN4 -B for improved perform- in 5 tuning unit ranges. For 110 V 60 cycle AC 0 USED. I, -- In! - $4.95 ance NEW $88.50 operation, built -in power supply. Shock Mount for above $2.95 LIKE NEW, SPECIAL $79.50 234 -258 MC RECEIVER AN /ARR -2 INVERTER POWER SUPPLY for above APN -4. INPUT: 'I'\ 1 'r \.1 FN-IS. TN-I0 and rN -5 -h BRAND NEW 11 tune UHF Tunable wo'",oh 24 'r t i'n11 ee :dime h .. _1.1'.1t. Itceii V DC. OUTPUT: 115 V AC, 800 cycles. Like schematic. Only a few at this low price! New $22.50 Couplet, with, I I,. l'.' t,.rd $5.95.... , $0 12 Power -Volt Inverter Supply for above APN -4. -522 2 -METER TRANSMITTER -RECEIVER i.ilte New. P.U.R. SCR ARB CRV 46151 NAVY AIRCRAFT RADIO RECEIVER Terrific buy! VIIF 'rran.mi r ter.h 5,,, ,,.,. 11,,, -I.lf, Sic. We Carry a Complete line of replacement parts and bill to 1.1' ill .1 hand,: 11111 - -O 5.- n- 1151111. .1 channels. scat- controlled. Amplitud' ,sdulal,.,l iccessories for above. ,IC.' -a,.. Me. i -tone super ml oo ü :,i Complete with all 1S tubes, top " rack with alo,-a case. LIKE: NEW! toning1.' land change. Complete $39.50 I'I-;CIALLY PRICED P,U.R. i1Sl., and dynamotor, like , LORAN R -65 /APN -9 RECEIVER A-. -,-,- h.. F'ou'l , `v $59.50 l'oe ,Imply'. I1,1,`'V S a. $32.50 -,r AC i.1.11 8.95 & INDICATOR SCR522 above roc. t :I Used in ships and aircraft. Deter- ARC -3 RECEIVER! mines position by radio signals from , AN 100 XMTR C 'ART-13 -WATT Complete with All tubes Exc. Used $21.50 known xmitters. Accurate to within = I Like NEW ... $33.50 I', of distance. Complete with 11 CHANNELS Crystal- controlled 17 -tube superhet. tunes from 100 tubes and crystal. IN LIKE NEW Con- 200 Kc to 156 MC., AM.. on any 8 preselected channels. -1500 28 -volt DC power input. Tubes: 1 -9002, 6 -6AKS. dition 1- 12SH7, $79.50 2 to 18.1 Mc . 3.12507, 1 -9001, 1.12H6, 2- 1251,17. f 1- 125L7. 1 -12A6. Used, with all parts, less tubes, crystal $29.50 110 V A.C. Power Supply Kit for above 15.00 and visor Special Factory Wired and Tested 19.95 INVERTER POWER SUPPLY for above APN -9. INPUT: $7050 Ai ARC -3 TRANSMITTER 24 V DC. OUTPUT: 115 V AC. 800 cy. Like New $22.50 USED ( . t-i^.ór Companion unit for above tunes 100 to 156 MC On 4rie,(ne+,...."'_ any 8 pre -selected channels. 9 tubes. crystal con- 12 -V. Power Supply for APN -9, like New P.U.R. omplete with Tubes T',i trolled. provides tone and voice modulation. 28V Shock Mount for above $2.95 DC Power input. Complete with all Tubes: 3 -6V6. 2.832A, 1- 125H7, 1 -695. Circuit diagram and connecting plugs available. ramous Collins Auto one Aircraft Transmitter. A11 2.6L6. Exc. Used Only Vo We carry a Complete line of replacement parts and 'W. MCR'. Quick change to any of ten pr chan- Like new condition 528.50 accessories for above. nels or manual tuning. Speech ampfifier!clippr r use. ARC PUSHBUTTON :,'bon or netic mike. Highly stable. highly -3 CONTROL BOX 55.95 , SEbi. r Built In EEO controlled calibrator. APN -12 3 -INCH SCOPE 'PSI `Is modulate 813 In final up to 90,5, class 'B." Ihrnl "Hier' Clam law at our low price! SCR -274 COMMAND EQUIPMENT Has Vertical and horizontal sweep AN'ART -13 XMTR, as above. In LIKE NEW ALL COMPLETE WITH TUBES Like BRAND with focus and intensity controls. r®._,t all and Crystal $89.50 condition, with tubes Type Description Used New NEW coaxial antenna Changeover motor. .'4 OC453 Receiver Complete with 11 tubes and 3JP1 e 0.16 Low Freq. Ose. Coil for ART -13 7.95 190 -550 Kc. $14.95 518.95 P.U.R. CR Tube. For 115 V. 400 Cycle AC n n 24V Dynamotor for ART -13 11.95 BC -454 Receiver 3 -6 Mc. 515.95 519.50 P.U.R. and 24 V DC. circuit dies- $14.95 We carry a complete line of spare parts for above. BC -455 Receiver 6 -9 Mc. $13.95 $19.50 P.U.R. gram included. LIKE NEW. ß 'nfts9 BC946 Receiver 550-1 500 Kr Complete all with r5100AP 'SCOPE. exc. used, like new, Q'42CO tubes. Brand New, in original Parking P U R. JJ DYNAMOTOR VALUES: Excellent BRAND 1.5 to 3 MC. Receiver Brand New P U R : :ti, all lung. va-,I. `nd CR tube$ A. 131LANh: NEW Used NEW ahoy, $69.50 Type Input Output 110 Volt AC Power Supply Kit for all 274 -N . n l DM -32A 28V 1.IA 250V .OSA 2.45 4.45 ARC -5 Receivers. Complete ,5th metal [ 8.95 BC -929 3 -Inch Scope, with all tubes, in :tractions Y JJ DM -33A 28V 5A 575V .16A Factory wired. tested. ready to operate .512.50 BRAND NEW $14.95 28V 7A 540V .25A 4.45 7.50 SPLINE!) TUNING KNOB for 274 -N nd Alt('-.- Conversion instructions, with diagram, for 100 V DM -34D 12V 2A 220V .080A 4.15 5.50 RECEIVERS. Fits BC -453. BC 454 and s 49e 19.50 other 44 AC operation $ 65 DM -35 12V 625V .225A - -. Only

DM -36 28V 1.4A 220V .O80A 1.95 2.95 _. I to :3 Mr Transmitter, Brand New.. .512.95 DM -42 28V 23A 515/1030/2/8 BC -457 TRANSMITTER-4 -5.3 Me. mplete $10.75 12.50 ;O, all tubes and crystal, BRAND NEW EE -8 FIELD PHONES MA 215/260 Like New .. J ff - ...... $7.95 Checked out, perfect working or- DM -53A 28V 1.4A 22011 .080A 3.75 5.45 ii(' 1: TRANSMITTER -5.3 to 7 Mc. Complotr h ,n tl t :, 1 crystal. der. Complete with all parts. Excel- I Like New) BRAND NEW $12.95 lent Condition. PE -73C 28V 20A 1000V .350A 8.95 510.95 Like N $7.95 LIKE NEW! Each 'P$14.50 BC -696 TRANSMITTER 3.4 Me Complete with $11.95 PE -86 28V 1.25A 250V .050A 2.75 3.85 All Tillie, d Crystal. Like New CC -4.56 Modulator ..USED 3.45 NEW 5.95 PEIOIC Dynamotor 12/24V Mum. IB -,1,1 New...7.95 AIL A('CESSORIES AVAILABLE i-131 A1'.,,t'b TG-34A CODE KEYER 0M -37 DYNAMOTOR. Input w;,...:,--,,,,,,, I,I' , !, '_ A. (Ito. -, V I,C -_5 Sta. vl'1t' h ¡.-I, 53.25 Self- contained automatic unit. f'?. MICROPHONES Checked Out, Perfect reproduces code practice signals T -17 1 :,rr ben Hand Alike. A. J/ recorded on paper tape. By use SCHEMATIC DIAGRAMS For"tru, °""ipso;;'"` 65Ç pas-. (-.r4 $4.45...... Brand New $7.95 0ó,,,y of built -in speaker. provides RS -38 \:,v,' Type Carbon hand Mike, ® code -practice signals to one or Please include 25% Deposit with order -Balance I Ike Ness 55.75 more persons at speeds from C.O.D.. or Remittance in Full. 5Oe Handling Charges j11,ß 5 to 25 WPM. on all orders under $5.00. All shipments F.O.B. Our HEADPHONES Checked Out, Perfect W Prior Model Description EXC. BRAND Like New, Warehouse. N.Y.C. All Merchandise subject to USED NEW $29.50 Sale and Price Change. H5.23 ..High Impedance $2.79.. $4.95 tJ Tested H5 -33 -LOW Impedance .. 3.15.. 5.45 ` ai Set of 15 Reel, Army : HS- 30....Low Imp. Ifeatherwt.) .90.. 1.65 Practice Lessons, REAM, EW. G & G RADIO SUPPLY CO. H-16 'U. . High Imp. 12 units) 3.75.. 7.95 original narking .. P U R. TELEPHONICS -600 ohm Low Impedance HEAD Telephone: CO 7 -4605 SETS. BRAND NEW. PER PAIR $3.95 CD -307A Cords. with PLS5 plug and .1826 Jack .99 ASK FOR OUR LATEST FREE BULLETIN OF BARGAINS IN 77 Leonard St. New York 13, N. Y. Earnbnne Cushion= for hnvr -pal' .50 MILITARY SURPLUS ELECTRONIC EQUIPMENT! i Printed in U.S.A. 98 CIRCLE NO. 183 ON READER SERVICE PAGE ELECTRONICS WORLD

www.americanradiohistory.com How to replace top quality tubes with identical top quality tubes

Most of the quality TV sets you are presently servicing were designed around special Frame Grid tubes originated by Amperex. More and more tube types originated by Amperex are going into the sets you'll be handling in the future. Amperex Frame Grid tubes provide 55% higher gain- bandwidth, simplify TV circuitry and speed up your servicing because their extraordinary uniformity virtually e.iminates need for realignment when you replace tubes. Amperex Frame Grid Tubes currently used by the major TV set makers include: 2ER5 2GK5 2HA5 3E117 3GK5 3HA5 4EH7 4EJ7 4E58 4GK5 4HA5 5GJ7 6EH7 6EJ7 6ER5 6ESB 6FY5 6GJ7 6GK5 f:HA5 6HG8 7HG8 8GJ7 If your distributor does not yet have all the Amperex types you need, please be patient -in some areas the demand keeps gaming on the supply. Amperex Electronic Corporation, Hicksville, Long Island, New York 11802.

CIRCLE NO 248 OM READER SERVICE PAGE www.americanradiohistory.com 111 EM11111 Y 1 MOM IAN I111eII 11111

RCA Calibration Center's Resistance RCA Frequency Standard being . =Recertifying Calibration Tubes on the Standard - accuracy 0.0002 ",. used to calibrate an oscillator RCA Static Characteristic Standard.

Calibrating portable Standard Cell on Voltmeter being calibrated on the RCA the RCA Primary Voltage Standard. AC Voltage and Current Standard.

BEGINS SERE

IEPENIIULE OkiiVIRMIANCE IS THE EA! RESULT

No reliability program for receiving tubes can be better 3 Sets of Calibration Tubes, selected to cover every type than the test instruments and equipments it employs. and family of tubes, are measured in the Calibration Center and used by the Cehter's personnel to periodically That's why RCA maintains the extensive Calibration verify the accuracy of all factory tube -testing equipments. Center in its Harrison, N.J., tube manufacturing plant (see photos above). The Center's responsibility: to assure that 4 Sets of Control Tubes, evaluated under the super- all measuring instruments and equipments, used in tube vision of the Calibration Center, constantly monitor the development from initial design through volume produc- repeatability of factory tube -testing equipments. tion, are accurate within rigidly specified limits. Here is Our Harrison Calibration Center is another example of the how this is accomplished: effort we make to assure the specified and dependable performance of every receiving tube that bears the em- The Calibration Center's own equipments are cali- 1 blem of RCA ... performance that benefits you through brated by standards (voltage, resistance, capacitance, customer satisfaction. frequency) whose values are regularly checked against standards of the National Bureau of Standards. SEE YOUR AUTHORIZED RCA DISTRIBUTOR 2 Measuring instruments used in all research, design, FOR TOP -QUALITY development and application laboratories are calibrated RCA RECEIVING TUBES directly from the Center's equipments. RCA ELECTRONIC COMPONENTS AND DEVICES, HARRISON, N.J.

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