•■IP r il 13 a r ® rarr Udul Jl (Tj uUd electronies Dept. 9 56. Fortis Green Road. Muswell Hill. London. N10 3HN. telephone: 01-883 3705 C - MOS 74 TTL ■in • • • • 1-24 25-99 1 00up 1-24 25-99 100 ♦ CD4000AE 23p 19p 15p 7400 14p 12p 10p CD4001AE 23p 19p 1 5p 7401 I4p 12p lOp CD4002AE 23p 19p I5p 7402 14p I2p lOp CD4006AE £1.59 £1.33 £1 .06 7403 15p 12 ip )0p CD4007AE 23p 19p 1 5p 7404 »6p 13p lip CD4008AE £1.75 £1.46 £1.17 7408 I6p 13p lip CD4009AE Use CD4049 7409 !6p I3p Up CD4010AE Use CD4050 7410 1*P 13p lip CD4011AE 23p 19p 1 5p 7413 29p 24p 20p CD40I2AE 23p 19p 15p 7417 27p 22 } P 20p CD4013AE 69p 58p 46p 7420 16p 13 P lip CD4014AE £1.75 £1.46 £1.17 7427 27p 22jp 18p CD4015AE £1.75 £1.46 £1.17 7430 16p 13 P lip CD4016AE 69p 58p 46p 7432 27p 22 ip 18p CD4017AE £1.75 £1.46 £1.17 7437 27p 22 J P 18p CD4018AE £2.51 £2.09 £1.67 7441 75 P 62p 50p CD4019AE 80p 66p 53 P 7442 65p 55p 43p CD4020AE £1.97 £1.64 £1.31 7445 85p 7 1 p 57p CD4021AE £1.75 £1.46 £1.17 7447 95 P 83 P 67p CD4022AE £1.83 £1.53 £1.22 7447A 95 P 83p 67p CD4023AE 23p 19p 15p 7448 85p 7 1 p 57p CD4024AE £1.26 £1.05 84p 7470 30p 25p 20p CD4025AE 23 P 19 P 15p 7472 25p 21 P I7p CD4026AE £2.79 £2.33 £1 .86 7473 30p 25p 20p CD4027AE 98p 82p 65p 7474 32p 26p 2 1 p CD4028AE £1.53 £1.28 £1.02 7475 47p 39p 3 1 P CD4029AE £1 .12 £1.76 £1.41 7476 32p 26p 21 P CD4030AE 7 1 p 59 p 47p 7482 75p 62p 50p CD4035AE £1.75 £1 .46 £1.17 7485 £1 .30 £1 .09 87p CD4040AE £2.01 £1.68 £1.34 7486 32p 26p 21 P CD4042AE £1.49 £1.24 99p 7489 £3.56 £2.80 £2.10 CD4049AE 69p 58p 46p 7490 49p 40p 32p CD4050AE 69p 58p 46p 7491 65p 55p 45 P CD4051AE £2.78 £2.32 £1.85 7492 57p 46p 36p CD4052AE £2.78 £2.32 £1.85 7493 49p 40p 32 P CD4056AE £2.12 £1.76 £1.41 7495 67p 55p 45p CD4060AE £2.51 £2.09 £1.67 74100 £1 .08 89p 72p CD4066AE £1.13 94p 75p 74107 35p 28p 22p CD4068AE 28p 24p I9p 74121 34p 28p 23p CD4069AE 28p 24p 19p 74122 47p 39p 3lp CD4070AE 28p 24p I9p 74141 78p 63p 53p CD4071AE 28p 24p 19p 74145 68p 58p 48p CD4077AE 7I P 59p 47p 74154 £1.75 £1 .48 86p CD4081AE 28p 24p 19p 74174 £1 .00 83p 67p CD4082AE 28p 24p 19 P 74180 £1 .06 88p 7lp C04085AE £1.28 £1.06 85 P 74181 £3.20 £2.50 £1 .90 C04086AE £1.28 £1.06 85p 74192 £1 .35 £1 .14 90p CD4093AE £1.56 £1.20 £1.04 74193 £1 .35 £1.14 90p CD4099AE £2.95 £2.46 £1.96 74196 £1 .64 £1 .34 99p SIEMENS LCD's LINE-0 | 1 LINEAR I.C.'s 555 (8 oin dio) V 55o • BHA0002 £3.01 MCI 358 (CA3C65) £1.16 SN76544N £1.81 555 (TO-99) T 81d • MCI 375 £1.48 SN76550-2 (TAA550) 89p 556 (14 pin dip) £1.29 • CA2111 £1.19 SN76552-2 81p CA3045 £1.69 MCI 455 ( 555T) 62p • SN76660N (T BA 120) 75p 703 (RF/IF Amp) 68p CA3046 88p MC 1 456CG £1.68 SN76666N (CA3065)£1 ..12 709 (8 pin dip) 38p CA3053 59p MCI 458CPI 84p 709 (TO-99) 45p CA3065 £1.60 MC1468G £2.18 • TAA263 £1.50 709 (14 pin dip) 39p CA3075 £1.64 MC1495L £4.24 TAA300 £2.16 710 (8 pin dip) 39p CA3078 £1.26 MC1496G 96p TAA310A £1.87 710 (TO-99) 45p CA3080 59p TAA320 £1.44 710 (14 pin dip) 44p CA3081 £1.86 MC3302P £1 .50 TAA350 £2.43 711 (TO-99) 51 p CA3082 £1.86 MC3401P 74p TAA370 £3.45 711 (14 pin dip) 44p CA3089E (T DAI 200) £2. 43 TAA550 75p 720 (A.M. Radio) £1.76 CA3097E £1.67 • MFC4000B 87p TAA570 £2.74 723 (TO-99) £1.09 CA3123E £1.76 MFC4060A 79p • TAA700 £5.03 723 (14 pin dip) 74p CA3401E (LM3900) 68p MFC6030A 79p • 741 (8 pin dip) 36p CA3600E £1.44 • MFC6040 96p TBA120S £1.25 741 (TO-99) 43p MFC6070 £1.66 TBA231 £1.02 741 (14 pin dip) 36p a7001 £5.34 • TBA281 (723) £2.59 747 (1 4 pin dip) £1.04 MM53I4 £4.80 • TBA500Q £3.16 748 ( 8 pin dip) 42p L005TI (TO. 3) £1.46 • MM5316 £9.99 • TBA520Q £3.85 748 (TO-99) 46p L036TI (TO. 3) £1.46 • TBA530Q £3.27 748 (1 4 pin dip) 49p L037TI (T0-3) £1.46 • MVR5V (T0-3) £1.45 • TBA540Q £3.72 753 (F.M. 1st. I.F.) LI 29 (SOT-32) 85p • MVR12V (T0-S) £1.45 • TBA550Q £5.29 £1.08 LI 30 (SOT-32) 85p • MVR15V (T0-3) £1.45 • TBA560CQ £5.29 75491 88 P • LI 31 (SOT-32) 85p • 75492 £1.10 • NE540L £1.25 TBA625A £1.03 < LM301 T (TO-99) 65p NE546A £1.16 TBA625B £1.03 < Regulofors 100 mA 78105WC aO-9?) 78L12WC (TO-92) 78H5WC (TO-92 1 60p 60p 60p 59p 67p Regulators 1 00mA 78L05AVVC ~> L- u * D NEW LED Lineor Cursors eoch device contains 10 light emWfing diodes in a 20pin dual- in-line pockoge. Ideal for solid Store analogue meters or dials. Type 101 RED £2.26 • PHOTO -DARLINGTON* Regulators 1A 7805UC (T0-220) 781 2UC (TO-220) 781 5UC (TO-220) 781 8UC (TO-220 1 7824UC (T0-220) £1.72 £1.72 £1.72 £1.72 £1.72 LM 1 820 LM2111 LM3900 £1.03 £ 1.12 69p ICL8038 £3.52 AV-1-0212 AY-1 -5051 AY-5-1224 AY-5-3500 AY-5-3507 AY-5-4007 £6.93 £1.44 £3.95 • £6.59 • £6.59 • £7.94 • MCI 303 L MC1306P MC1310P MCI 31 2 MCI314 MCI 31 5 MCI 327 MCI330P MCI 339 P MCI 350 MCI 351 MCI 352 MCI 357 £1.84 80p SL610C SL611C SL612C SL613C SL620C SL621C SL622C SL623C SL624C SL630C SL640C SL641C SL645C £2.03 £2.03 £2.03 £4.31 £3.06 £3.06 £7.62 £5.57 £2.84 £1.87 £3.75 £3.75 £3.75 TCA270Q TCA760 TCA800Q TCA830S TCA940 £5.24 £2.16 £7.24 £1.04 £2.25 T DA 1054 T DA 1200 T DAI 405 TDA14I2 TDAI4I5 TDA2010 TDA2020 £1.50 £2.43 80p « 80p « 80p * £3.00 £3.75 ULN2111A £1.52 £2.39 £2.42 SL650C £9.85 £4.13 SN75491N 88p • £4.62 £1.12 SN75492N £1.10 • 83p SN7600I N (TAA611) £1.82 £1.52 SN76003N £3.30 64p SN76013N £1.98 88p SN76023N £1.98 88p SN76227N (MC1327) £1.89 £1.52 SN76532N £1.88 ZN4I4 £1.26 MINITR0N Minitron Filament Disploy bi-directional 0.36" 301 5F 0-9 L/H d.pt. 3015G - 1 £1.08» SPECIAL PURCHASE SEVEN SEGMENT DISPLAYS litronix Snibn Monsanto & COMMON ANODE R/H Dec. Pt COMMON ANODE L/H Dec. Pt. COMMON ANODE - I COMMON CATHODE R/H Dec. Pt. Our Price RED DL707P DL707 DL701 DL704 £1 . 82 « 0.3 GREEN M*>N5I RED MAN7I YELLOW MAN81 ORANGE MAN3610 MAN 52 MAN72 MAN8? MAN3620 MAN53 MAN73 MAN83 MAN3630 MAN54 MAN74 MAN84 MAN3640 £1.82. £1.82. £1 82. £1 32 . ]_♦ 10‘ 100 ♦ 10- 100 ♦ 1 ♦ 10« 100 ♦ > Red I6p 15p 13p • 27p 24p 22p • 1 8p * I6p 1 4p • Green 27p 2 4p 22p • 33p 30p 27p • 30p 27p 25p • Orange 2V P 24p 22p • 33p 30 P ?7p • 30p 27p 25p • Yellow 34p 31 p 29 p • 35p 32p 29p • 35p 33p 30p • Low Cost Red GoAsP Moforolo MLED 500 in o T092 pockoge. '5p • NEW Opto-isolotors IL1 (4N25 » TILII6) 6 pin industry standard package 2 . 5KV isolation El. 00 • NOTICE Postoge & Pocking Charges With the recent inc.eose in postol charges and a continuing ine'eose in packaging cost* we have been forced »o review our policy. Henceforward: 1 . Orders valued ot £5 or more will be post free. 2. AIIU.K. ‘small pockoge’ orders will go first class mail. 3. Minimum postage & packing charge will increase to 20p. GREEN XAN51 RED XAN7I YELLOW XAN81 XAN52 XAN72 XAN82 XAN54 XAN74 XAN84 £1.49. £1 49a £1.49* 0.4' 0 . 6 ' GREEN MAN45I0 MAN 4570 MAN 4530 MAN4540 RED MAN4710 MAN4720 MAN 4730 MAN4740 YELLOW MAN4810 MAN4820 MAN 4830 MAN 48 40 ORANGE MAN4610 MAN 4620 MAN 4630 MAN 46 40 C. A L/H f-A. C.C. L/H 9 c - Dec. Pt. - 1 Dec Pt. - i RED DL747 DL746 DL750 DL749 £2.32* £2.32« £2.32* £2.32e £2 42, VAT INCLUDED NOTE. MAN 4000 series pinouts ore 14 pin dil the some os MAN50;70 & 80 series. Items marked with a • include 8% VAT Items unmarked include VAT at 25% CALI.ERS WELCOME ADVERT. No.1. of Series B. artisement elektor november 1975 — 1101 Use DOR AM components for your project c The doorwSy to Amateur Electronics DORAM'S NEW CATALOGUE OFFERS THOUSANDS UPON THOUSANDS OF QUALITY ELECTRONIC COMPONENTS AND AUDIO ACCESSORIES FROM TRUSTED BIG NAME MANUFACTURERS. ALL COMPONENTS ARE INDIVIDUALLY CODED AND PRICED • MANY NEW ^ COMPONENTS ADDED FROM CUSTOMER REQUESTS. ^ 16 EXTRA PAGE DATA SECTION. ^ UNIQUE FREE UP-DATE PRODUCT INFORMATION SERVICE DURING LIFE * SPAN OF CATALOGUE. ^ ALL COMPONENTS SENT BY RETURN OF POST. POST AND PACKING FREE (only applies for Great Britain, N. Ireland and B.F.P.O. Nos. - overseas orders F.O.B.) NO QUIBBLE REPLACEMENT PART SERVICE P The doorway to amateur electronics PLEASE PRINT BLOCK CAPITALS DflMm I DORAM ELECTRONICS LIMITED I P. O. Box TR8 | Leeds LS12 2UF I enclose 60p. Please send me by return my . new Doram Catalogue. (Overseas orders I except for B.F.P.O.. please add 30p for I oost and packing surface only). NAME ADDRESS Post Code 1102 — elektor november 1975 publisher's notice y 1 1 b j-nMyTiiHi-f Many Elektor circuits are accompanied by designs for printed circuits. For those who do not feel inclined to etch their own printed circuit boards, a number of these designs are also available as ready-etched and predrilled boards. These boards can be ordered from our Canterbury office. Payment, including £ 0.15 p & p, must be in advance. Delivery time is approximately three weeks. Bank account number: A/C No. 1 1014587, sorting code 40-16-1 1 Midland Bank Ltd, Canterbury . circuit edwin amplifier austereo 3-watt amplifier austereo power supply austereo control amplifier austereo disc preamp universal frequency reference distortion meter a/d converter tap sensor minidrum gyrator minidrum mixer/preamp minidrum noise miniature amplifier light dimmer beetle equa amplifier electronic loudspeaker mostap car power supply digital rev counter (control p.c.b car anti-theft alarm mos clock 5314 clock circuit mos clock 5314 display board mos clock timebase minidrum tap minidrum ruffle circuit automatic bassdrum microdrum aerial amplifier coil less receiver for MW and LW tap preamp twin minitron display twin led display twin decade counter recip-riaa disc preamp 76131 maxi display versatile digital clock dil-led probe big ben 95 compressor tv sound car clock (2 boards) car clock front panel (transpareni plastic) tup/tun tester tup/tun tester front panel p.c.b. and wiring tester rhythm generator M 252 7400 siren CA3090AQ stereo decoder kitchen timer capacitance meter NEW: circuit tap preamp front panels: power input volume tone width clamant clock, alarm clamant clock, time signal ota pll tv tennis, main pcb tv-tennis, modulator/oscillator frequency counter tap power tv tennis 5-volt supply * with solder mask number issue price % VAT 97-536 6 1.20 (25) HB1 1 5 1.10 (25) HB1 2 5 0.55 (25) HB1 3 5 1.50 (25) HB14 5 0.65 (25) HD4 5 1.10 ( 8) 1437 1 1.65 ( 8) 1443 3 0.90 ( 8) 1457 1 0.60 ( 8) 1465A 2 0.80 (25) 1465B 2 0.55 (25) 1465C 2 1.05 (25) 1486 6 0.55 (25) 1487 6 0.45 ( 8) 1492 4 2.20 ( 8) 1499 1 1.20 (25) 1527 2 0.50 (25) 1540 2 1.05 ( 8) 1563 4 1.25 ( 8) •.only!) 1590 1 0.55 ( 8) 1592 4 1.40 ( 8) 1607A 1 1.15 ( 8) 1607B 1 0.85 ( 8) 1620 4 0.70 ( 8) 1621 A 2 0.70 (25) 1621 B 3 1.10 (25) 1621C 3 0.55 (25) 1661 2 0.95 (25) 1668 1 0.95 (25) 3166 5 0.80 (25) 4003 4 1.80 (25) 4029-1 2 1.40 ( 8) 4029-2 2 1.40 ( 8) 4029-3 2 1.40 ( 8) 4039 2 0.50 ( 8) 4040A 3 0.95 (25) 4409 2 1.50 ( 8) 4414B 6 1.10 ( 8) 5027A+B 2 1.85 ( 8) 5028 2 1.25 (25) 601 9A 3 1.20 (25) 6025 2 1.40 (25) 7036 t red 6 1.75 ( 8) 7036-3 6 0.90 ( 8) 9076* 4 1.70 ( 8) 9076/2A 4 1.90 ( 8) 9106* 5 0.55 ( 8) 9110* 5 0.80 (25) 9119* 5 0.75 (25) 9126* 5 0.80 (25) 9147* 5 0.75 ( 8) 9183* 5 0.75 ( 8) number issue price % VAT 1626A 7 1.55 (25) 1626B 4 1.55 (25) 1626C 4 1.55 (25) 1626D 4 1 .55 (25) 1626E 4 1.55 (25) 4015-13 7 1.30 ( 8) 4015-16 7 0.85 ( 8) 6029 7 1.10 (25) 9029-1 A* 7 3.80 ( 8) 9029-2* 7 0.90 ( 8) 9033* 7 1.30 ( 8) 9072* 7 1.90 (25) 9218A* 7 0.80 ( 8) All prices include V AT at the rate shown in brackets. Editor Deputy editor Technical editors Art editor Drawing office Subscriptions W. van der Horst P. Holmes J. Barendrecht G.H.K. Dam E. Krempelsauer Fr. Scheel K. S.M. Walraven C. Sinke L. Martin Mrs. A. van Meyel UK. Staff: Editorial : T. Emmens Advertising : P. Appleyard Editorial offices, administration and advertising: 6 Stour Street, Canterbury CT1 2XZ. Tel. Canterbury (0227) — 54430. Telex: 965504. Elektor has been published every two months until August 1975; it now appears monthly. Copies can be ordered from our Canterbury office. The subscription rate for 1975 is £ 3.60 (incl. p & p); the first issue (Nov/Dec 1974) will be included in this at no additional cost. Single copies: £ 0.35 (incl. p & p: £ 0.45). Subscription rates (airmail): Australia/New Zealand European countries outside UK USA All other countries 8 issues £ 7.20 8 issues £ 5.20 8 issues £ 6.25 8 issues £ 6.40 Subscribers are requested to notify a change of address four weeks in advance and to return envelope bearing previous address. Members of the technical staff will be available to answer technical queries (relating to articles published in Elektor) by telephone on Mondays from 14.00 to 16.30. Letters should be addressed to the department concerned: TQ = Technical Queries; ADV = Advertise- ments; SUB = Subscriptions; ADM = Administration; ED = Editorial (articles submitted for publication etc.); EPS = Elektor printed circuit board service. The circuits published are for domestic use only. The submission of designs or articles to Elektor implies permission to the publishers to alter and translate the text and design, and to use the contents in other Elektor publications and activities. The publishers cannot guarantee to return any material submitted to them. All drawings, photographs, printed circuit boards and articles published in Elektor are copyright and may not be reproduced or imitated in whole or part without prior written permission of the publishers. Distribution: Spotlight Magazine Distributors Ltd., Spotlight House, 1, Bentwell road, Holloway, London N7 7AX. Copyright © 1975 Elektor publishers Ltd — Canterbury. Printed in the Netherlands. selektor 1109 tv tennis 1111 The popularity of television tennis games has prompted Elektor to produce a design than can easily be built by the home constructor for a modest cost. Although several designs have previously appeared on the market, it was felt that there was a need for a simple circuit using a minimum of components. frequency counter 1121 Logic IC's are so cheap that it is possible to build a digital frequency counter for a very small outlay. The circuit described here is based on the popular 74 TTL logic family. The first part deals with the basic counter, and in a subsequent article additions to the instrument will be described. humming kettle — J.P. Kuhler jr 1129 active flash slave — R. Buggle 1129 tap-power 1130 This 'TAP-power' circuit has been specially designed for the TAP preamp system. It includes touch-controlled switches for turning the whole equipment on or off and for selecting the main power amplifiers or the head- phone amplifiers, a power supply for the TAP pre-amp, simple headphone amplifiers and a disc preamplifier. N.B. See the 'Missing link' on page 1 156. clamant clock (1) 1134 Any horologist who keeps a digital clock in the same room as conventional clocks cannot but feel sad to see it sitting there, mute and reproachful amongst its more vociferous brothers, its only sound the feeble humming of the mains transformer. In this article we look at various ways of providing the digital clock with a voice, so that it can draw our attention to the fact that it is keeping time far more accurately than any mere mechanical clock. lie detector —J. Jacobs 1143 brake lights for model cars — R . Zimmer 1143 universal ota pll 1 144 Elektor has taken a lead in drawing attention to the possibilities of the PLL (Phase Locked Loop). The Universal OTA (Operational Transconductance Amplifier) PLL described here is a printed-circuit module which can form the nucleus of many different types of receiver. tv test pattern generator 1149 A television pattern generator is one of the most useful TV service aids. It simplifies checking of the video stages, adjustment of picture geometry, and perhaps most important, setting up of convergence in colour receivers. Using logic IC's for the generation of the test pattern allows the construction of a simple and reliable circuit. with a pencil point — W. Schmidt 1153 market 1154 1104 — elektor november 1975 advertisemer BOOK CORIVER DIGITAL ELECTRONIC CIRCUITS AND SYSTEMS NOEL M. MORRIS MACMILLAN BASIC BOOKS IN ELECTRONIC SERI ES J.C. Clule The principles of assessing the reliability of electronic equipment, including the mathematic background, component failure data, and methods to improve reliability, are described and e: plained at a level suitable for degree and diploma students upwards. £2.6 ELECTRONIC EQUIPMENT RELIABILITY Using the example of the electronic calculator to illustrate many of the systems, this text begins with a description of basic logic functions, including a full coverage of boolean algebra and Karnaugh maps. It then goes on to describe high-speed switching elements, logic gates, calculating functions, asynchronous and synchronous counters, shift registers and display decoding circuits. £2.45 Experiments with oper- ational amplifiers Linear integrated circuit applications by G.B. Clayton This book covers a wide range of practi- cal operational amplifier applications. It provides circuits which include compo- nent values, and suggest measurements that can be made in order to study cir- cuit action. The experiments will be useful for a large variety of measurement and instru- mentation systems. The way in which performance errors are related to the characteristics of the particular amplifier used in a circuit are treated in an appendix. Paperback £ 3.30 Hardcover £ 6.85 by G.B.Clayton This book is concerned with the newf circuits now available, important fc such things as signal measurement an processing systems. After first looking at how to use ope ational amplifiers as measurement ampl fiers and in active filter circuits, th book then deals with the more recentl introduced linar integrated circuit monolithic integrated circuit modi lators, four quadrant multipliers, timer waveform generators and phase locke loops. Paperback £ 3.3< Hardcover £ 6.8! ORDER FORM Please Supply the following (all prices include postage and packing) copy/copies of Experiments with Operational Amplifiers by G.B. Clayton at £ 6.85 per copy (hard cover) copy/copies of Experiments with Operational Amplifiers by G.B. Clayton at £ 3.30 per copy (paperback) copy/copies of Linear Integrated Circuit Applications by G.B. Clayton at £6.85 per copy (hard cover) copy/copies of Linear Integrated Circuit Applications by G.B. Clayton at £3. per copy (paperback) copy/copies of Digital Electronic Circuits and Systems by Noel M. Morris £ 2.45 per copy copy/copies of Electronic Equipment reliability by J.C. Cluley at £ 2.65 per coj To: Technical Book Services Ltd., Dept. 7, 25 Court Close Bray Maidenhead Berks SL6 2DL I enclose £ Name Address /ertisement elektor november 1975 — 1105 loin the Digital Revolution reach yourself the atest techniques of Jigital electronics omputers and calculators are only the beginning of the igital revolution in electronics. Telephones, wristwatches, V. automobile instrumentation — these will be just ome of the application areas in the next few years .re you prepared to cope with these developments? his four volume course — each volume measuring 1 f " x 8^" and containing 48 pages — guides you tep-by-step with hundreds of diagrams and questions "irough number systems, Boolean algebra, truth tables, e Morgan's theorem, flipflops. registers, counters and dders. All from first principles The only initial ability ssumed is simple arithmetic U the end of the course you will have broadened your iorizons, career prospects and your fundamental under- tanding of the changing world around you. Design of Digital Systems Bookl as 1 Also available - a more advanced course in 6 volumes: 1. Computer Arithmetic 2. Boolean Logic 3. Arithmetic Circuits 4. Memories & Counters £5.95 plus 50 p p 5. Calculator Design 6. Computer Architecture Offer Order this together with Digital Computer Logic & Electronics for the bargain price of £ 9.25, plus 50 p p & p. & p. Design of Digital Systems contains over twice as much information in each volume as the simpler course Digitai Computer Logic and Electronics. All the information in the simpler course is covered as part of the first volumes of Design of Digital Systems which, as you can see from its contents also covers many more advanced topics These courses were written so that you could teach yourself the theory and application of digital logic. Learning by self-instruction has the advantages of being quicker and more thorough than classroom learning. You work at your own speed and must respond by answering questions on each new piece of information before proceeding to the next. 3uarantee - no risk to you If you are not entirely satisfied with Digital Computer Logic and Electronics or Design of Digital Systems, you may return them to us and your money will be refunded in full, no questions asked. Designer Manager Enthusiast Scientist Engineer Student Digital Computer Logic and Electronics A Self -instructional Course a w G .Z^e>o£!» Book 4 Basic computer logic Book fl i Logical ' circuit 1 elements • Book 1 | Designing circuits [ to carry out ‘ logical functions Digital Logic and Electronics A S«« mlructm* Ccuw Book IIim « i £3.95 plus 50 p packing and surface post anywhere in the world Quantity discounts available on request. Payment may be made in foreign currencies. VAT zero rated. E7~l To: Cambridge Learning Enterprises, FREEPOST, St. Ives, Huntingdon, Cambs PE 1 7 4BR * Please send me set(s) of Digital Computer Logic & Electronics at £ 4.45 each, p & p included. * or set(s) of Design of Digital Systems at £ 6.45 each, p & p included. * or combined set(s) at £ 9.75 each, p & p included. Name Address * delete as applicable ( No need to use a stamp — just print F REEPOST on the envelope 1106 — elektor november 1975 advertiseme Have you seen this years most important component catalogue yet? • -r i feNRy'sl fi'Wuli I HENRY'S 1975 M | CATALOGUE ^ IS NOW AVAILABLE Don't buy another electronic component until you’ve consulted the Henry's 1975 issue! It's packed with more items than ever before - over 5000 in all, making the Henry's range of electronic components the largest in the UK for the home constructor. There are literally dozens of new lines and new ranges to get excited about ! And many components are selling at reduced prices. Get your copy soon, and start reading these 200 pages of vital statistics about electronic components. If you don't, you'll miss out on a lot of kits, projects and test gear, apart from all the other products. ONLY 50p + 20p p & p Complete with FREE 50p Discount Voucher! FREE to Educational Establishments when ordered on official headed notepaper. Get your copy NOW - send remittance of 70p (cheque or P.O.). MIDLANDS: NEW ELECTRONICS StbRE OPEN. 94/96 UPPER PARLIAMENT STREET NOTTINGHAM TEL 40403 LONDON: 231 TOTTENHAM COURT ROAD W1. (LOWER SALES FLOOR) ELECTRONIC FOOTBALL & TENNIS WITH THE FABULOUS VIDEO SPORT ON YOUR OWN TV Play three exciting elec- tronic ball games. FOOT- BALL. TENNIS. HOLE IN THE WALL on your own TV. Just plug Video Sport into the aerial socket of your TV and away you go. Completely safe for you, your children and your TV. Mains operated. OUR INCREDIBLE PRICE £29.50 INCL. DEMONSTRATIONS NOW IN ALL CENTRES. VAT HI FI SINCLAIR MODULES & KITS SINCLAIR PROJECT 80 TEXAN STEREO AMPLIFIER Features glass fibre pc board, gardners low field transformer 6-IC's 10-transistors plus diodes etc. Designed by Texas 4 Instruments engineers for Henry's jiul P W 1972. Overall size 15 V' x 2 V x 6Y’ mams operated Free teak sleeve with every kn £29.95 (carriage 50p.) (also built and tested £39.501 TEXAN STEREO FM TUNER Features capacity diode tuning lead and tuning meter indicators, mams operated High performance and sensitivity Overall size m teak sleeve 8” x 2 V x 6 Y* Complete kit with teak sleeve. £26.25 (HP 50p I (also built end tested £31 20) ST80 Stereo preamplifier Audio Filter Unit Z40 15 Watt Amplifier Z60 25 Watt Amplifier PZ5 Power Supplies for 1 or 2 Z40 PZ6 Power Supplies (S Tab) for 1 or 2 Z40 TRANSFORMER FOR PZ8 FM TUNER STEREO DECODER IC20 power amp kit PZ20 power supply for 1 oi 2 IC20 £14.05 £8.17 £6.40 £8.17 £5.72 £8.18 £4.86 £14.05 £9.34 £9.34 £5.88 PACKAGE DEALS (carr./packg 3‘jp ) 2 x Z40 ST80 PZ5 £29.32 2 x Z60 ST80 PZ6 £32.60 2 x Z60 ST80 PZS trans £40.42 805 Kit . £42.25 SINCLAIR SPECIAL PURCHASES ‘Project 60 stereo preamp £7.94 (post 20p ) 'Proiect 605 Kit £23.44 (post 25p ) AM/FM MODULES LP1179 LP1171 Combined AM/FM tuner modules, together with a small number of R.C.'s Ferrite Aerial, make up a sensitive FM/MW/LW tuner. 6 Volts supply, supplied with data and circuit sheets. All Henry's prices inclusive of VAT LP1171 combined IF strip £4.60 LP1179 FM front end and AM gang £4.6( £8.62 the pair. Suitable Ferrite aerial 87p. Henru's RADIO Electronic Centres 404-406 Electronic Components & Equipment 01 4028381 H> f 309 PA Disco Lighting High Power Sound 01 723 6963 Electronics 303 Special offers and bargains store Centres Opt All mail to 303 Edgware Road London W2 ! B\N 9am 6pm Prices correct at time of preparation Subject to change without notice l bO t FREE Brochure on New Whether professional, student, teacher or amateur, the field of electronics can open up a new world for you. ■a*cutca»o Huy it w ith .Vmai CROFTON don t just sell kits, we offer you a technical back up service to ensure your success The following is a selection of some of the more popular kits - ^ Mullard CCTV Camera PE CCTV Camera ★ PE Rondo Quadraphonic Four Channel Sound , (Designer Approved ) J Electronic Ignition J Electronic Flash ^7 F > W Tele-Tennis Game JT UHF Modulator y Bench Power Supply J Wobbulator £ All ETI Top Projects rt Many of the Elektor Projects NOTE: PC Bs for most published projects available to order CROFTON ELECTRONICS LTD Dept.A 124 Colne Road. Twickenham, Middx 01 898 1569 CRYSTALS Fast delivery of prototypes and production runs INCLUDING: Statek LF crystals in T05 package Buckman LF, clock and mobile radio crystals Astro Filter crystals Jan General purpose crystals Crystals for Elektor clock designs available. Interface Quartz Devices Limited, 29 Market Street, Crewkerne, Somerset. Tel.: (046031) 2578 Telex: 46283 eieKtor november 19/b — 1107 LECTRONIC COMPONENT DISTRIBUTORS P.0. Box 25 Canterbury Kent Telephone: Canterbury (0227) 52139 Elektor printed circuit boards and binders. Prices as in this issue Component kits and individual components available by return of post from stocks at Canterbury. All prices include VAT and P.+P. 741-8/14DIL £0.22 7400 £0.15 7401 £0.15 7405 £0.19 7447 £1.20 7473 £0.30 7495 £0.69 74121 £0.32 MM5314N . . £4.77 E.1109 £6.08 7038A £3.68 TBA231 . . . CA1310AE. CA3080 . . . CD4011AE . CD4017AE . CD4049AE . TBA120. . . . £ 1.02 . £2.27 . £0.79 .£0.23 .£1.76 .£0.67 . £1.24 SFE 6 mA (6 MHz Filter) £0.90 l/C EXTRACTOR £0.55 NE555V £0.65 l/C INSERTER £1.40 2N3055 . . . . £0.54 Crystals for any requirement PH 100 5-digit 30 MHz freq. counter £99.50 Above types are partial examples. Write or phone for details. 7 p.m. to 9 p.m. phone Dover (0304) 812332 Stock List free on request. r RCA CMOS PRICES ARE DOWN CMOS from the leadox) manufactured at their new 1 off puces co-moo 0.17 CD4019 0.46 CD4041 0 69 CD40G0 0.92 CD4001 0 17 CD4020 0.92 C 040-12 069 CD4063 0.90 C04002 0 17 CD4022 0.79 CD4043 0 83 CD4066 0.58 CD4006 0.97 CD4023 0 17 CD4044 0.77 CD4068 0.18 CD4007 0.17 CD4024 064 C04045 1.15 CD4069 0.18 CD4008 0 79 CD4025 0 17 CD4046 1.10 C04070 0.18 CD4009 0 46 CD4026 1.42 CD4047 0 74 CD4071 0 18 CD4010 0 46 CD4027 0.46 CD4048 0.46 CD4072 0.18 CD4011 0 17 CD4029 0 94 CD4049 0 46 CD4073 0.18 CD-1012 0.17 C 04030 0 46 CD4050 0 46 CD4075 0 18 CD4013 0 46 CD4031 1.81 CD4051 0 77 CD4076 1.27 CD4014 0 83 CD4033 1.14 CD4052 0.77 C04077 0.18 C04015 0 83 CD4034 *83 CD4053 0 77 C D4078 0 18 C04016 0 46 C04035 0 97 CD4054 095 C D4081 0 18 CD4017 0 83 C04036 7 47 CD4055 1 08 CD4082 0.18 CD40I8 0.83 C04040 0 88 CD4J5G 1 08 CD4085 0.57 CD1086 CD4093 CD4095 CD4099 MCI 4501 MC14502 MC 14508 MC14510 MC14511 MC14518 MC14520 MCI 4528 MC14553 MCI 4566 MCI 4585 MM74C14 057 0 66 0 86 1.50 0.32 0.65 4 20 1.26 1 95 1 03 1 03 087 4 07 1.21 1 45 1 16 RCA 1975 CMOS Databook 400 pages of data sheets and 200 pages of circuits. applications and other useful information £2.30 (No VAT) + 37p p&p New 1975 MOTOROLA McMOS Databook £2.30 (No VAT) * 47p p&p CLOCK COMPONENTS, KITS, etc. 6 DIGIT ALARM CLOCK KITS - complete except for case - bleep alarm — intensity control — snooze . . . With 0.3" LED displays £19.80 With 0.5" LED displays £23.76 QUARTZ CRYSTAL TIMEBASE - suitable for any digital clock 32.768 kHz Mm. Xtal: High accuracy/stability for clock or watch .... £ 50 cps Crystal Timebase Kit - will provide stable 50 cps for any clock 1C giving time accurate to within a few seconds a month; contains small PCB, 32.768 kHz Xtal. 3 CMOS IC's. trimmer, zener, C's. R's, 1C skts £ DL704E 0.3" Red Common Cathode 7 segment LED display .... only FND500 0.5" Red Common Cathode 7 segment LED display £ 5LT01 0.5” 4 digit green Phosphor Diode clock display with am/pm . MK50253 4 or 6 digit 1 2 or 24 hi format alarm clock 1C with snooze . . AY51202 4 digit clock 1C specially designed for use with 5LT01 . . . MM5314 4/6 digit clock 1C . . £4.44 AY51224 4 digit clock 1C MK5030M CMOS watch 1C for LED display with date and seconds . . . Display PCB's are available for clocks & counters (up to 8 digits) SOLDERCON 1C PIN SOCKETS (using these & nylon supports, 28 pin Skt: 30p) The sensible method for lowest cost sockets for IC's, displays, CMOS, TTL Strip of 100 for 50p 400 for £2.00 1000 for £4.00 3000 for £10.50 7-way Boss Switch: 7 ultra min. toggle switches in 14 pin DIL £ 2.60 ADD VAT at 8% (higher rate does not apply to any of the above) 15p p&p on orders under £3. Despatch is First Class Post BY RETURN. Price List & Data sent free with any order, or on request (an sae helps) Official Orders welcomed, written, phoned or telexed, from Univs, Polys, Schools, Govt. Depts, Nat. Inds., Rated Cos. etc. Fastest delivery for R & D SINTEL 53(K) Aston St. Oxford Tel. 0865 43203 Tlx. 837650 A/B ELECTRONIC OXFD 3.60 6.40 .85p 1.50 5.80 5.60 5.60 4.25 £19.50 £ £ £ £ IMTEL Technology spoken here. AMBIT supplies coils, filters and semiconductors, based on a theme of wireless and entertainment elec- tronics. Linear ICs: CA3089E FM IF System £1.94* CA3090AQ PLL MPX decoder £3.75 MC1310P PLL MPX decoder £2.20 TBA1 20AS FM I F and detector £1.00" SN76660N FM IF and detector £0.75* uA720/CA31 23 AM radio system £1 .40 TBA651 AM radio system £1.81 uA753 FM I F gain block £0.99 MCI 350 FM IF gain with AGC £0.70 NE560/1/2 HF PLL systems, each £3.19 NE565/7 LF PLL tone decoders £2.75 NE566 Function generator £2.00 LM380 2w AF amp. £1 .00 LM381 stereo low noise preamp £1.85 TBA810AS 7w AF amp. £1 .30 ICL8038CC One chip waveform source, with sine square and triangle outputs. Inc. 12 pages of data and applications £3.10 £0.80 see the 723CN DIL voltage regulator 7800 series voltage regulators price list for full details. Coils and filters from TOKO. 455kHz IFTs with capacitor. 10mm square type 10E 27p each. 7mm square type 7P 27p each. Set of three of either 7P or 10E 60p. 10.7 MHz IFTs with capacitor(s). 10mm square type 10K interstage IF 30p . 2 x 10mm square type 10E ratio detector type system for 10.7 MHz 50p K586 10.7 MHz quadrature coil for such ICs as the CA3089E, TBA1 20 etc. 30p TK342 10.7 MHz dual quadrature coil for ultra low distortion . ( 2 x 10K) 55p 10.7 MHz FM IF filters CFS 10. 7M ceramic filter, sim.to SFE and FM4 types for WBFM at 1 0.7MHz 40p 3132 6 pole linear phase filter IF 2.25 3125 4 pole linear phase IF filter 1.30 AM IF filters for 455/470 kHz. MFH41T 4kHz BW mechanical IF filter for transistor/IC use £1.45 MFH71 T 7kHz BW mechanical IF filter for transistor/IC use £1.45 CFT455/470C 6kHz ceramic IF filter for 455 or 470 kHz £0.50 CFU050D Hi Q 6kHz ceramic IF filter for 470kHz use. £0.55 Full cataolgue system 40p, Or shortform price list free with an SAE. Telephone: (0277)216029 Telex 995194. Radio modules and kits for AM/FM EF5600 FM tunerhead with 5 varicap tuned circuits, AFC & AGC. The best you can buy for the money £10.00. EC3302 FM varicap head. 3 tuned circuits with AFC. Good value at £5.00 MT3302 AM/FM gang tuner with the same circuit for FM as EC3302 £5.00 8319 Dual mosfet, AFC, AGC, 4 tuned circuits, varicap control FM head. £9.00 1 185 FM IF system with single ceramic IF filter and the functions of the CA3089 1C IF system. £4.35 991 200 FM IF strip, with mute, AFC, AGC, meter drive, 8 pole IF filter and a dual detector for 0.1% THD. £9.00 99720 MW varicap tuner, with RF stage ceramic IF filter and AGC. £9.95 9720 - the 99720 in kit form £8.00 Also in our general catalogue: 15cm wirewound slider potentiometers, a comprehensive car radio kit, FM tun- er kits, Larsholt FM tunersets,. DAU trimmers, 15:1 ratio hyper abrupt varicap tuning diode for MW/LW- with 300+ pF swing, (matched gps.) ambit AMBIT international: 37 High Street, Brentwood, Essex, U.K. All prices exclude VAT. UK customers please add 25% VAT and 20p per order postage. Min. CWO £1.00. Overseas customers: please allow extra for postage. Any excess postage or VAT will be credited. Payment may be made with Access, Eurocard, Mastercharge. Simply quote card number. 1108 — elektor november 1975 advertiser™ elektor backi are still available Edition No. 5 is a summer circuit issue. It contains over one hundred cir- cuit designs all proved and mostly original. Price 80p (U.K. including postage). Prices for single copies (1, 2, 3, 4 and 6, including P & P*) U.K. Europe U.S.A. Australia/New Zealand 45p 65p 78p 90p may be subject to increase in postal rates We shall be exhibiting a variety of working projects selected from current and future issues of Elektor, in the Internationa* Audio Festival and Fair. October 20 - 26 at OtyroP' 3 ' London .^L / □ • *- Isaimdl 7 B / □ ■ \ 1 GRAND HALL ENTRANCE FRO OLYMPIA WAY rtB Members of our Editorial Staff will be on hand to answer your technical queries, and we look for- ward to seeing you there. ELEKTOR PUBLISHERS LTD. 6, Stour Street, Canterbury, CT1 2XZ, Tel.: 0227-54430. tennis elektor november 1975 — 1111 The popularity of television tennis games has prompted Elektor to produce a design that can easily be built by the home constructor for a modest cost. Although several designs have previously appeared on the market, it was felt that there was a need for a simple circuit using a minimum of compo- nents. In order to keep costs down the TV tennis circuit generates the most basic ‘picture’ possible, i.e. two ‘bats’ and a ‘ball’. The ball is ‘served’ from one side of the screen or the other and the players move their bats up and down the screen to intercept the path of the ball. If the ball strikes a bat it is re- turned, otherwise it leaves the side of the screen and a ‘new ball’ must be served. Should the ball reach the upper or lower edge of the screen during its traverse across the screen it will ‘re- bound’. The upper and lower bound- aries are, however, not displayed on the screen. The output of the TV tennis game is used to modulate a VHF oscillator so that the game may be plugged direct into the aerial socket of a television. Principle of operation For those not familiar with TV a brief resume of the principles involved may prove helpful. A TV picture is, of course, generated by an electron beam scanning across the phosphor-coated face of a cathode-ray tube in a zig-zag fashion from top to bottom. At the end of each horizontal line the beam flies back to the left hand edge of the screen and starts the next line slightly lower down the screen. Each complete scan (frame) of the picture con- sists of either 405 or 625 lines, depending on the trans- mission standard. To reduce the bandwidth required to transmit the video infor- mation a complete frame is not transmitted in a single scanning of the picture, but is made up of two ‘fields’ con- taining half the number of lines in a frame. These two fields are interlaced with each other to make up a complete frame. Fields are transmitted at a 50 Hz rate, therefore frames are transmitted at half that rate, i.e. 25 frames per second. The video waveform In order to build up a picture on the screen the brightness of the trace must be modulated by varying the electron 1112 — elektor november 1975 tv tenn beam current. This is controlled by the amplitude of the video waveform. So that the scanning of the electron beam in the TV set is in synchronism with the received signal in order to build up the picture correctly, field sync, pulses are transmitted (at the end of each field) and line sync, pulses are transmitted (at the end of each line). To distinguish sync, pulses from video information, sync, pulses are negative- going and confined to a voltage below that required for zero beam current (black level). Video information oc- cupies a range of voltages above black level up to the voltage required to saturate the TV tube phosphor (peak white level). Circuitry in the TV dis- tinguishes between sync, pulses and video information. Field sync, pulses also have a longer duration to dis- tinguish them from line sync, pulses. From the foregoing some of the require- ments for the circuit become apparent. Firstly, the circuit must contain oscil- lators capable of generating field and sync, pulses at the appropriate fre- quencies (50 Hz and 15625 Hz re- spectively). Secondly, circuitry for generating the bat and ball waveforms, and for controlling the movement of these, is required. Fortunately, since we are concerned only with white bats and ball on a black background the only modulation required is peak white level or black level, so analogue circuitry is not needed to produce these waveforms, and digital logic circuits can be used to generate the rectangular pulses necess- ary. Block Diagram The operation of the circuit is be understood with the aid of a bloc diagram (figure 1). Sync, pulses froi the field and line oscillators are mixe in the video mixer and then fed to tl modulator. They are also used to coi trol the timing of the other waveform All the video waveforms are generate using monostable multivibrators and ; the generation of the ‘bats’ is simple: this will be considered first. The lef hand player’s horizontal bat generate IC5 is triggered continuously from th line sync oscillator. A presettable triggt delay is incorporated so that the pub appears a little time after the line syn pulse. This ensures that the bat appeal some way in from the left hand edge c vertical mnis elektor november 1975 — 1113 screen. The right-hand player’s izontal generator IC3 incorporates a £er delay so that this bat appears r the right-hand edge of the screen. :e the triggering occurs after every sync pulse the result would be a ver- 1 band of white the full height of the en. This is where the vertical bat gen- or (IC6 left, IC4 right) comes in. s monostable is triggered from the i sync pulses via a delay which is tinuously variable by the player, s determines the vertical position of bat. The delayed pulse from the ver- l bat generator gates the pulses from horizontal oscillator so that they are y allowed through for the duration this pulse. The result is thus a verti- bar on the screen whose vertical ition can be varied by the player and >se height (length of the bat) is irmined by the duration of the ver- 1 pulse. The same applies for both left- and right-hand bats. $ ball is generated in a similar manner h two monostables (IC1 and IC2). vever, since the ball is continuously ring this in effect means that for cement to the right the horizontal ger delay is increasing all the time, for movement to the left it is de- lsing. downwards movement the vertical §er delay is increasing, while for up- ds movement it is decreasing. Of rse it is necessary to reverse the ction of ball travel when the ball ces a bat or the upper and lower ndaries. This part of the circuit rates as follows: horizontal ball pulse generator 1) is triggered via a delay by the line c pulses. The delay, and therefore horizontal position of the ball on screen, is controlled by the output an integrator, which is fed with a voltage and therefore generates a p which varies the trigger delay arly. The slope of the ramp (positive- negative-going) and hence the direc- i of ball travel is determined by state of flip-flop FF2. If FF2 is ially reset the ball will travel to the Lt. However, should the ‘ball’ out- and the right-hand ‘bat’ output h be high at the same time (i.e. the strikes the right hand bat) then the put of N7 goes low, resetting FF2 reversing the horizontal direction, en the ball strikes the left-hand bat n the output of N8 goes low, re- :ing the flip-flop and causing the ball 4v „ ba 1 » b all^ ba t black level l.4v lllllllllllllllll HnnnnnnniTnl iiiDinin iivrr line sync ifield sync. Ov pulses pulse 9029 -2b Figure 1. Block diagram of TV Tennis game (excluding modulator/oscillator). Figure 2a. The horizontal and vertical wave- forms are gated together as shown to produce the bat and ball display. Figure 2b. The complete video waveform as seen on an oscilloscope. to travel to the right. If the ball does not strike a bat it will leave the side of the screen and will not return until it is ‘served’, since the state of the flip-flop is not changed and the integrator output will eventually saturate in one direction or another. Service will be dealt with in the description of the full circuit. Travel of the ball in the vertical direc- tion is controlled in a similar fashion, but here the change of direction occurs at the upper and lower boundaries. The lower border of the picture corresponds with the leading (negative-going) edge of the field sync pulse, so change of direc- tion at this boundary is accomplished by gating the ball signal with the field sync pulse in N5. To change ball direc- tion at the top of the picture a monostable (IC9) is triggered by the trailing edge of the field sync pulse. The output pulse of the monostable is gated with the ‘ball’ signal to reset FF1. A timing diagram showing how the various pulses are gated together to produce the bat and ball outputs is given in figure 2, together with the general appearance of the complete waveform as seen on an oscilloscope. Complete Circuit The complete circuit is given in figure 3. Field sync pulses are produced by the circuitry in box A, which consists of an astable multivibrator driving a monostable to produce pulses of the correct length. Box B contains similar circuitry, but operating at a much higher frequency, to produce line sync pulses. The Q outputs of these monostables (to produce the negative- going sync pulses) are fed via D3 and D4 1114 — elektor november 1975 tv tern 3 5V I r tennis elektor november 1975 — 1115 igure 3. The complete circuit of the TV nnis game. The modulator/oscillator rcurt is shown inset at the bottom right- in d corner. igure 3a. Suggested modification to derive eld sync pulses from the mains for mains rily versions of the game. This should give a lore stable picture than the free-running eld oscillator. igure 4. Circuit of the mains power supply jr TV Tennis. Parts list for figures 3, 5 and 7 Resistors: R1 ,R2,R39,R43,R55 = 4k7 R3,R4,R47 = 33 k R5,R9 = 10 k NTC R6,R10 = 820£2 R7.R11 = 5k6 R8.R12 = 18 k R1 3,R1 6,R1 7,R20,R21 ,R24,R25, R28,R29,R32,R33,R36,R56,R59 = 10 k R14,R18,R22,R26,R30,R34,R40,R44, R57 = 100 k R1 5,R1 9.R23.R27.R31 ,R35,R53 = 2k2 R37.R41 ,R48,R52 = 2k7 R38.R42 = 10 £2 R45 = 1 k8 R46,R49,R54 = 1 k R50 = 12 k R51 =470 £2 R58 = 27 k PI ,P2 = 4k7 lin. preset P3,P6 =47 k lin. P4,P5,P7,P8 = 100 k lin. preset Capacitors: Cl ,C2 = 4/i7, 10 V C3 = 22 n C4,C8,C1 1 ,C1 4,C1 7,C20,C23 = 1 00 n C5,C6 = 15 n C7 = 390 p C9,C1 5,C21 = 1n5 Cl 0,C1 6,C22 = 180 p Cl 2, Cl 8,C24,C26,C27,C28,C29 = 470 n Cl 3 = 68 n C19,C25,C30 = 220 n C31 ,C32 = 47 jU, 1 0 V C33 = 3n3 C34 = 1 50 n C35 = 3p3 C36 = 4 ... 20 p trimmer C37 = 47 p Semiconductors: T1 ,T2 f T3,T4 / T5 f T6 > T7,T8,T9,T10,T1 1 , T1 2 = BC547B T1 3 = AF239 D1 ... D14 = 1N4148 I Cl ,IC2,IC3,IC4,IC5,IC6,IC7,IC8,IC9 = 74121 IC10JC11 = 7400 IC1 2 = 7402 IC1 3 = 7474 Sundries: L = 4 wdg, 1 mm (p Cu, 0 8 mm H F Tr = 60 £2 240 £1 impedance con- verter (see text) to the junction of R58 and R59. This portion of the circuitry fuctions as the video mixer. Black level occurs when the Q outputs of IC7 and ICS are both high and the bat and ball inputs to D1 1 , D12 and D13 are all low. The voltage at the junction of R58 and R59 is then solely determined by the value of these resistors and is about 1.35 V. When a sync pulse occurs then the junction of these two resistors is held down to about 1 V via D3 or D4. When bat or ball signals occur the inputs to Dll, D12 or D13 go high, so the potential at the junction of R58 and R59 becomes about 4 V. If the unit is to be used for mains only operation the astable in box A can be dispensed with and field sync pulses may be derived from the 50 Hz mains by the modifi- cation shown in figure 3a. PI, R5, R6, Cl and C2 are omitted; the sync pulses are fed in at the original connection to the positive side of Cl on the board, and the track between this point and the output of N2 (pin 6 of IC10) must be broken. The sync pulses are buffered by emitter followers T1 and T2 to avoid loading the monostables excessively. The buffered sync pulses are then fed via the trigger delays to the appropriate monostables which generate the hori- zontal and vertical components of the bat and ball waveforms. The trigger delay circuits are all identical in prin- ciple and merely vary in component values. The trigger delay for IC3 oper- ates as follows: normally T5 is turned on by base current through R23. Its collector voltage (and hence the A in- puts of IC3) is low. The cathode of D7 is held at a few volts positive by the voltage via R21 from P7 (max. 2.5 V), and since T2 is turned off the anode of D7 is at 0 V. Cl 5 thus has a voltage across it equal to the voltage on the cathode of D7 minus the base-emitter voltage of T5. On the leading edge of the line sync pulse T2 turns on, forward biassing D7. Cl 5 thus charges until the voltage across it is 5 V - VbeT2 - Vd 7 - VbeT5 = 3 V approximately. On the trailing edge of the sync pulse T2 turns off. The voltage on the cathode of D7 therefore reverts to its initial value (the potential sup- plied via R21 from P7). However, since the voltage across C 1 5 is still 3 V then the base of T5 must be negative. T5 therefore turns off. Cl 5 now charges via R22 until the voltage on the base of T5 reaches about 0.7 V when T5 turns on and the collector voltage goes low, triggering the monostable. It is evident that the trigger delay is dependent on the time taken to charge Cl 5 after T5 has been turned off, which is in turn dependent upon the voltage applied to the cathode of D7 from P7. The trigger delay may thus be varied by a d.c. voltage, in the case of the bats derived from the various poten- tiometers, and in the case of the ball from the emitters of T1 1 and T12. In the case of the ball, as explained earlier, the trigger delay in both hori- zontal and vertical directions is continu- ously varied to achieve motion of the ball. Horizontal movement of the ball is controlled by FF2 and the integrator constructed around T12. When FF2 is preset the Q output is high and C32 charges via P9 and R50. The potential on the emitter of T12 therefore rises. This is applied to R13, thus continu- ously increasing the trigger delay and making the ball move to the right. When FF2 is cleared (reset) then C32 dis- charges via P9 and R50. The voltage on the emitter of T12 falls, thus decreasing the trigger delay and making the ball move to the left. The rate of charge or discharge of C32, hence the speed of the ball, is determined by the setting of P9. Vertical ball movement is controlled in a similar manner by FF1 and Til. Note that in this circuit the AND-gates shown in the block diagram have been replaced by NOR-gates connected to the Q out- puts of the monostables. This is of course exactly equivalent to AND-gates connected to the Q outputs (De Morgan’s theorem). The horizontal bat trigger delays are preset, by P7 for the right-hand player, and by P4 for the left-hand player. This allows the position of the bats to be adjusted to a few cm away from the sides of the screen. The vertical position of the bats is continuously adjustable, by P6 for the right-hand player and P3 for the left-hand player. P5 and P8 are presets used to adjust the bat position 1116 — elektor november 1975 tv tenr Figure 5. Printed circuit board and com- ponent layout for the modulator/oscillator circuit. Figure 6. Printed circuit for the TV Tennis game. Figure 7. Component layout for the main board. so that P6 and P3 are effective over the full height of the screen. Service of the ball It is evident that if the state of FF2 is not reversed by a coincidence between the ball and one of the bat signals then the voltage at the emitter of T12 will continue to rise or fall as C32 either charges or discharges, until it reaches either zero volts or supply minus the base-emitter voltage of T12. The ball •will then disappear off one side of the screen or the other and will not return. For this reason (as well as for the rules of the game) it is necessary to ‘serve’ the ball when this has occurred. Ideally the ball should emanate from the bat of the player who is serving. However, in practice this is difficult to achieve as it means that at the instant of service the vertical ball trigger delay must be matched to the vertical bat trigger delay. Since the delay circuits are independent component tolerances will make this unlikely. It is, however, possible to make the ball service depen- dent upon the bat position at the time of service, though not coincident with it. Service is accomplished as follows: for a service by the left-hand player the 4-pole switch SI is closed. Thi produces several results. Firstly points ) and Z are connected to ground via R38 This clears FF1 and presets FF2 so tha when the ball is served it will travel up wards and to the right. 9079 A tennis elektor november 1975 — 1117 7 nxiorionn UUOUOOTJ onnnnnn uuuuuoa aannnnn UOOOOOa aaaaaaa uuooooo • jQLonnnaa oouuuua uooaou so the ball travels in a direction determined by the states of FF1 and FF2 (i.e. up and to the right). Service by the right-hand player oper- ates, so to speak the same way but backwards, i.e. pushing S2 grounds point X so that the ball still travels up- wards. However, point Y is grounded so that the ball travels to the left, and point U is grounded to discharge C32 so that it starts from the right. The verti- cal starting position is determined by the emitter potential of T1 0. Modulator and oscillator The only part of the circuit which remains to be described is the modu- lator/oscillator which converts the video output at point A into a VHF signal suit- able for feeding direct into a television aerial socket. This part of the circuit is shown inset in figure 3. An AF239 forms the basis of the oscillator circuit which is tuned to the required fre- quency by the coil L and C36/C37. The output may be fed direct into an unbal- anced 50 - 75 £2 coaxial cable termin- ating in a normal TV coax plug, or if the TV has continental type 240 - 300 £2 twin feeder input then the output must be fed through an inverse balun trans- former before feeding into the 300 £2 feeder. Power Supply A power supply which is absolutely free from mains ripple is absolutely essential for the TV Tennis game. The reason for this is fairly obvious. Any mains ripple will cause a variation in the input voltages to the trigger delay circuits, and hence in the trigger delays. This pro- duces distortion of the picture as the trigger delay varies down the screen height. For portable operation a 6 V lantern battery or accumulator may be used, with a decoupling capacitor across the supply pins on the board (say 1000 /i), whilst for mains only oper- ation the 5 V power supply shown in figure 4 is strongly recommended. It is based on an integrated circuit regu- lator the LI 29. This IC will provide a stabilised voltage of 5 V from inputs up to 20 V and will supply a maximum current of 600 mA. However, to mini- mise power dissipation within the IC it is recommended that a transformer with a 6.3 V RMS secondary voltage be used. This will give a D.C. input to the IC of about 9 V. The bridge rectifier is made up of 4 1-amp diodes such as 1N4001. Note that C3 should be a tantalum type to reduce output noise and any tendency to R.F. instability. Components Dl, D2, R1 and R2 correspond with figure 3a. *oint U (R51) is connected to positive upply, thus charging C32 rapidly and lolding the ball off the left-hand side of he screen. Point T (cathode of D14) is connected to the emitter of T9, whose )ase is fed via R39 from P3 (left-hand bat control). The voltage on C3 1 is thus constrained to slightly above the emitter voltage of T9, thus determining the ver- tical position from which the ball will start. When the switch is released the constraints on C3 1 and C32 are released Construction and adjustment The p.c. board and component layout for the VHF oscillator are given in figure 5, for the main board in figures 6 and 7, and for the power supply in figure 8. A point-to-point wiring dia- gram is given in figure 9. Slider poten- 1118 — elektor november 1975 tv tenn VA'JW,' 1 V\ vv>> S&vfev'fc *• .-i mm&Mi*.. »%'-<>'> vsv'V gWapMifSp k&xo jJjxv: fv^.w.v.vyvWhr»v»T^»V.v.v.vJ •* It*: 9»: mmmtmmzmd tennis elektor november 1975 — 1119 i iN iVyS Figure 9. Point-to-point wiring diagram showing how the various boards are intercon- nected with each other and with the switches 4 . and potentiometers. fmM %SS'% *S& y • / * • • • » • 'QSS&I 1 r 0 •’fJUUUVJULlt, 1120 — elektor november 1975 tv tern tiometers are used for the bat controls as these give easier control than rotary types and are sufficiently robust for domestic use. The oscillator is mounted on a separate board as it must be housed in a completely screened box to avoid radiated interference and to minimise pickup of other transmissions. A small diecast or pressed aluminium box with a lid is suitable. The main board housing should also be a metal box. Having checked that the circuit is correct and that the power supply is giving the correct voltage before connecting it to the unit, power can then be applied and the output of the VHF oscillator plugged into a TV set. Due to the har- monics generated extending into the hundreds of MHz the unit will function on both VHF and UHF although the line oscillator frequency is of course different for405 and 625 line reception. Initially all the potentiometers should Parts list for figures 4 and 8 Resistors: R1 ,R2 = 470 JT2 Capacitors: Cl = 470 /i/1 6 V C2,C4 = 100 n C3 = 10jU/6 V (tantalum) Semiconductors: D1 = DUS D2 = 4.7 V zener B = Bridge rectifier, or 4 x 1 N4001 IC1 = LI 29 Sundries: Transformer, 6.3 ... 8 V (r.m.s.) second- ary Figure 8. Printed circuit board and com- ponent layout for the power supply. be set at the middle of their travel. If oscilloscope is available the waveform point A can be checked, if not, th proceed as follows. For VHF operate the TV set should be tuned to channel or 9, though with pushbutton turn there is often no indication of t channel the set is tuned to, so it must tuned over the entire band until t signal is picked up. By adjusting the 1 tuning and C36 it should be possible tune in the signal. At first the pictu will be rather chaotic as the field a] line sync oscillators are not running the correct frequency. By adjusting ] it should be possible to obtain vertic lock, i.e. the picture will stop Tolling Of course with mains field sync there no adjustment and if lock is n< obtained it will be necessary to adju the frame hold control on the TV se It may be found that, due to the tolc ances of Cl and C2 it is not possible obtain the correct field sync frequenc The oscillator may run at 25 Hz, which case the picture will lock b will jitter considerably. In this case C and C2 should be reduced to 2 fi 2. may be found that a black bar appea in the centre of the screen. This because the field sync oscillator running at 100 Hz, and PI should 1 adjusted until normal lock is obtaine Having obtained vertical lock t] picture will probably consist of random pattern of white dashes. 1 can now be adjusted until the tv bats appear on the screen. If the lii sync oscillator is tuned to a multip of the line frequency then four ba may appear. Having obtained tl correct number of bats the horizont positions of the left- and right-har bats may be adjusted by P4 and F respectively. The final adjustment is to the range < the vertical bat controls. With tl slider controls set to the centre < their travel P5 and P8 are adjusted < that the bats are halfway down tl screen. It should now be possible t traverse the bats over the enti screen height, and some furth< slight readjustment of P5 and F may be necessary to achieve this. The unit is now ready for use and should be possible to serve a ball fro either side of the screen by pressii the appropriate service button. Due 1 the simple nature of the circuit it me be found that pressing the servii button causes slight picture jitter, bi this should not prove inconvenient j practice. I jquency counter elektor november 1975 — 1121 \\& m \s ** ' <*%%. ppW-T'K.o^ \L NS ^ ^\rCV)^ 1 * uie Q ° e ° X s%sf%* Specification Input sensitivity (frequency measurement) 1 .7 V p-p. Input sensitivity (period measurement) 2.6 V p-p. with an input risetime of 0.5 jLts/V. Maximum input frequency 18 MHz. l its basic form the instrument is a six- igit frequency/period meter. The basic aunter/latch/display is shown in fig- re 1 , which is the circuit of two stages f the counter, showing how the 7490’s re cascaded, and how the intercon- ections between the latch and reset lputs are made. The segment series re- store are shown dotted, as the circuit lay be used with either Minitron or ED displays, and series resistors are ot required with Minitrons. l p.c. board for one stage of the ounter/latch/display decoding is given l figure 2. Six of these boards are re- uired for the six-digit counter. The isplays are all mounted on a single oard to which the counter boards are 'ired, either with wire links, as in fig- re 3, or if LED displays are used, via sgment resistors, as in figure 4. igure 5 shows the pinout and voltage/ urrent curve for a Minitron display ype 301 5F. Note that for use with a 447 decoder the points shown as round are in fact commoned to +5 V. l p.c. board for use with Minitron dis- lays is shown in figure 6, and the com- onent layout in figure 7, showing the onnections to a counter board. igure 1. Two stages of the counter/latch/ lisplay circuit, showing how the counters are ascaded. Parts list for figure 1 IC's: IC1 = 7490 Resistors: IC2 = 7475 R1 = 1 k IC3 = 7447 R a • • • Rg = 1 80 £1 ( LED display only) 1122 — elektor november 1975 frequency coiin Figure 2. P.c. board for one decade of t counter, latch and display driver. Figure 3. Component layout for figure 2 usi Minitron displays. Figure 4. Component layout for figuri showing segment resistors for LED displa Figure 5. Pinout and characteristics of Mi tron. Figure 6. P.c. board for Minitron displ; Figure 7. Component layout for Minitr display. Figure 8. Pinouts of three popular LED C plays. * RESET O c c c ' /, 1 q ~ P - C 3 If] c o C Id D ® — • 93 ’* LATCH 1 ,3 C d ♦ q :> Qs. 3 IC2 £ 3 3 O C c c c c c c c 1C 3 1 1 \ TEST ^ <2> R b Rb 3 3 3 3 3 3 3 3 v 0 DP R* - f Rb R 3 -TrT R. R«1 « i m { Rao • * r ic 16 i A 15 i B 14 i 3 i J ---12 i C 11 l h 1 l o I H 9 i Figure 9 shows the corresponding boai for use with LED displays. Most cor mon anode LED displays are pin cor patible with respect to the cathode (se ment) connections, but some types ha 1 multiple anode connections (usual pins 3 and 9). These are catered for c the board, but if a display is used th; does not have anode connections 1 these pins it may or may not be neces ary to cut them off, depending c whether or not they are N.C. (no coj nection). The pin connections of three popuk LED displays are given in figure 8. F( further data on common-anode LEDdi plays see Elektor No. 3 page 451 . Photographs 1 and 2 show the gener, appearance of the display/counter boar assembly, and also how the segmer resistors are soldered to the back of th display board when using LED display: Control logic To make the decade counter just di scribed function as a frequency counte various control signals must be applie to it. Firstly, the pulses to be counte must be gated into the first stage of th counter. Secondly, after the cour period has ended the count must b stored in the latch. The counter mm then be reset ready for the next couni All these functions are performed b the control logic, the circuit of which i given in figure 10. The counter will operate in two basi modes, frequency and period. In th frequency mode incoming pulses ar counted for a period of time dependen upon the counter gate period. Thus i the incoming frequency was 100 kH and the gate period 1 s then the coun displayed would be 100000. In the period mode the internal fre quency reference of the counter is itsel counted and is gated by one cycle of thi incoming signal. Thus, if the interna reference frequency was 1 00 Hz, an< the signal to be measured had a perioi of 1 s, then the count displayed wouli be 000100. Of course the decimal poin on the display board can be shifted si that this could be displayed as 1 .00 (se< below). The control logic operates as follows. I equency counter elektor november 1975 — 1123 I® I® ®l r® MirSJITROfVJ DISPLAY ®1 ♦ t> a t> bt> l O 90 cO 'O °o * r * c ' V- mC \ * > w r • > ■— c * *V_ > > C c C C C c c c B p 3 3 3 3 3 3 3 C C C C c c c c B 3 3 3 3 3 3 3 3 C C c c c c c c B\ 3 3 3 3 3 C C c c c c c c J 3 3 B\ 3 3 3 C c c c c c c c 3 3 3 3 Opcoa SLA 1 Pin 1 Cathode a 2 Cathode f 3 NC 4 NC 5 NC 6 Cathode DP 7 Cathode e 8 Cathode d 9 NC 10 Cathode c 11 Cathode g 12 NC 13 Cathode b 14 Common Anode Hewlett-Packard Pin 5082-7730 1 Cathode a 2 Cathode f 3 Common Anode 4 No pin 5 No pin 6 Cathode DP 7 Cathode e 8 Cathode d 9 NC 10 Cathode c 1 1 Cathode g 1 2 No pin 1 3 Cathode b 14 Common Anode Data Lit 707 Pin 1 Cathode a 2 Cathode f 3 Common Anode 4 NC 5 NC 6 Cathode DP 7 Cathode e 8 Cathode d 9 Common Anode 10 Cathode c 11 Cathode g 12 NC 13 Cathode b 14 Common Anode 1124 — elektor november 1975 frequency count > < J a co □ □ ui j nnnnnnn □s OOUUOUU rinnrinnn U0UUUU7J riaonricia roa OOUUTJOU lOQ tjdoouuu -ariaanj nnnnnnn Qq xjooao on ooannria h XT T T 1 T T T ° : rc roT rc rc rt : a| ■o A A A A A A A A A A the basic version of the frequency counter the reference frequency is de- rived from the 50 Hz mains. This is adequate for many applications, but provision is made for the addition of a crystal-controlled reference for greater accuracy and versatility. The 50 Hz reference is taken from the secondary of the mains transformer that supplies power to the counter. The A.C. waveform is rectified by the bridge thus providing a 100 Hz full-wave rectified waveform. This is fed to the input of SI O/2 7413 NAND Schmitt trigger) via Rl, and is clamped to 4.7 V by D1 . The 100 Hz pulses from the out- put of SI are divided down to 50 Hz, 10 Hz, 5 Hz, 1 Hz and 0.5 Hz by FF1 , IC4 and IC5. The 50 Hz, 5 Hz and 0.5 Hz outputs are used to provide * « 10 ms, 100 ms or Is gate periods de pending on the position of switch SI For ease of operation, a fifth deck or SI can be used to switch the decima point (figure 10b). The switch position: can then be labelled ‘MHz*, ‘kHz’ anc ‘sec*. In the first three positions of SI th< gate pulse is fed from Sib into Schmit trigger S2, together with the signal to bt measured. Thus when the gate signal from Sib is a logic ‘1’ the signal to be measured i: allowed through S2 to the counter in put. The latching and reset signals an derived in the following manner, refer ring to the timing diagram figure 1 1 During the gate period (waveform I from Sib ‘high’) the gating signal I holds pin 9 of N 1 and pin 11 of N2 high The outputs C (to latch) and D (to resei inputs of counter) are thus low. The latch is thus in the ‘store’ mode and the reset inputs of the counter are low, sc the counter counts the pulses which are gated through S2 to output E by the gating signal. At the end of the gate period wave- form B and waveform A (from SI a) both go low. A is connected directly to pin 8 of N 1 and B is connected via R4 and C 1 . The negative-going edge of B is differentiated (B*). N1 performs the logic function C = A + B so a short posi- tive-going pulse appears at output C, momentarily putting the latches into requency counter elektor november 1975 — 1125 lO S y. 1 = x 100 Hz 2= * 10 Hz 3 *= xi Hz 4 = period 05V FF1 ... FF2= IC1 =7473 S1...S2 • IC2 = 7413 N1...N4 = IC3 = 7402* IC4 = 7490 IC5 = 7490 IC6 = 74121 D2 . . . D3 = DUS E = Counter C = Latch D = Reset * $ee text 9033-10 Figure 9. P.c. board and component layout For LED display. c igure 10. Circuit diagram of control logic. the ‘enable data entry’ mode and thus storing the count. This pulse also trig- gers the monostable IC6, which per- forms several functions. Firstly, its Q output holds the input to SI high, thus blocking the 1 00 Hz pulses to FF1 . It also holds pin 12 of N2 high, so the output remains low. The Q output clears FF1 . When the monostable resets the timebase will restart. The next posi- tive transition of the A signal will be inverted by N3, and the input (pin 12) of N2 will be pulled low by R5. Since the other input is connected to the B signal, which is already low, the out- put of N2 goes high for the duration of the positive A pulse, thus resetting the counter. When the B signal goes high again the counter commences another count and the sequence repeats. D4 lights when the gate is open. The pulse length of the monostable IC6 can be varied by PI. It is apparent that this pulse length determines the time for which the timebase is disabled, and hence the interval between counts. This facility is useful, as with a short count interval the continual variation in the last digit can be annoying. A longer count interval will alleviate this. On the other hand, when a rapid succession of measurements is to be taken then a short count interval is useful. Period Measurement To measure the period of the incoming Parts list for figure 10 Resistors : R1 ,R2 = 470 £2 R3 = 180 ft R4 = 10 k R5 = 330 £2 PI =47 Min. Capacitors: Cl = 100 p C2 = 220 /Lt, 1 0 V C x = 100 n Semiconductors: D1 = zener 4.7 V, 250 mW D2,D3,D5,D6 = DUS D4 = LED IC's: IC1 = 7473 IC2 = 7413 IC3 = 7428 (7402) IC4,IC5 = 7490 IC6 = 741 21 Sundries: SI = 4-pole 4-way switch (or 5-pole 4-way, see text) 1126 — elektor november 1975 frequency counte nn □ 9312 - 13 - 14-15 9033 H+A+F B 1 v y 9312 - 13 - 14-15 9033 — 12 waveform the 100 Hz reference i counted whilst the gate, latch and rese functions are derived from the signal tc be measured. To do this the switch SI i set in position 4. This disables the time base, connects the gate input of S2 t( the Q output of FF2 and connects th< 100 Hz signal to the other input. It alsi connects the latch circuitry input A U the incoming signal. The sequence o operations is thus as follows: on tht first negative transition of the inpu signal H FF2 clocks and its Q outpu goes to 4 P thus opening the counte gate. 100 Hz pulses (G) are now gatec through SI (E) and are counted. On tht next negative transition of the inpu signal the flip-flop FF2 again clocks anc the Q output goes to ‘O’, thus closinj the gate. The gate period is thus ont complete cycle of the input waveform The input waveform drives the latch reset circuitry in a similar manner t( requency counter elektor november 1975 — 1127 14 ul c T S & J i b 3 c • C Tp 5 | i b p i q 3 » q P tic p C 2 c IC5 3 1 c IC3 P r x X q IC6 3 c P c 3 4 c 3 3 c 3 q P Tlj i G 3 ■ i q P q P it q 3 1 — i mf • — 0 •— © » 8 S ( i_X_t 4P- x "" 4 Reset Latch^ ■ 9033 : igure 11. Timing diagram of counter in fre- luency measuring mode. : igure 12. Timing diagram of counter in >eriod measuring mode. : igure 13. P.c. board for control logic. : igure 14. Component layout for control ogic. :hat for a frequency measurement, and :he timing diagram is shown in fig- are 12. Of course, the A signal is now he input signal, and the B signal is the Q output of FF2. With a 100 Hz reference frequency and 1128 — elektor november 1975 15 Parts list for figure 15 Resistors: R1 ,R2 = 3k9 R3 = 6k8 R4 = 470 S2 R5 = 100£2 R6 = 1 80 £2 R7 = 1 k R8,R9,R10= 1 £2 PI = 1 k, preset Semiconductors: Capacitors: Cl ,C2 = 1 00 n C3,C4 = 1 n C5 = 2200 /i, 1 6 V C6 = 220/i,4 V C7 = lOjti, 16 V C8 = 470 £1, 6,3 V B1 = bridge rectifier B20 C2200 D1 =3 A diode D2,D3 = DUS D4 = zener 4.7 V, 400 mW T1 = TUP T2,T3,T5 = TUN T4 = TIP 2955 Sundries: FI = fuse 2.5 A slow blow Trl = transformer 12 V, 2 A requency counter humming kettle / active flash slave elektor november 1975 — 1129 J.P. Kuhlerjr. humming kettle igure 15. Power supply for frequency punter. igure 16. P.c. board and component layout f power supply. he gate periods of 10 ms, 100 ms and s the range of the instrument is mited. It is only possible to obtain a ull-scale reading in the period mode dien the period is 9,999.99 seconds, or a period of 1 s the display will be nly 000100, a resolution of one art in a hundred. Clearly, for short eriod measurements a higher reference requency is necessary to obtain a larger ount and hence a better resolution, rovision is made for feeding in an ex- irnal reference frequency by breaking he circuit at the point marked ‘EXT ;EF’. In the frequency mode the maxi- lum and minimum frequencies which an be measured are limited by the gate eriods. For instance with a 1 s gate eriod a frequency of 1 00 Hz will only e measured with a resolution of one art in a hundred, whilst with a 10 ms ate period an input frequency of reater than 99.9999 MHz would cause he counter to overrange. However, ince the upper frequency limit of the TL counters used in the circuit is only 8 MHz anyway, this problem does not rise. ^ printed circuit board and component lyout for the control logic board are iven in figures 13 and 14, showing the onnections to the switch. tower supply V suitable power supply for the fre- uency counter is shown in figure 15. 'his is well decoupled against mains- •orne interference and has a 100 Hz >utput for the reference frequency. A >oard and component layout for the >ower supply are given in figure 16. Vs the complete frequency counter Iraws about 2 amps, the series regulator ransistor T4 should be mounted on an dequate heatsink. If the unit is housed n an aluminium case then the back of he case should prove suitable, n a future issue we shall be describing dditions to the frequency counter, LOtably an input preamplifier to in- rease the input sensitivity. 14 Those who have in the course of time lost the whistle of their domestic kettle and the unfortunate ones who do not possess a whistling kettle at all, who must boil water without the aid of an acoustic signal, are encouraged by the author not to resign themselves to this unsatisfac- tory situation. A very modest amount spent on components together with a little work puts a ‘humming kettle’ within everyone’s grasp! The circuit is so simple that further ex- planation is hardly necessary. As the temperature increases, the resistance of the NTC drops until at a certain moment (adjustable with Pj) transistor T! cuts off, so that T 2 conducts and the buzzer is activated. R. Buqqle active For those who have often been annoyed by badly illuminated flash photographs and also dislike the tangle of cables involved in using two flashguns, the flash slave is the only solution. The author spent quite some time build- ing several slave units before arriving at the design presented here, which has the advantages that it requires no separate supply voltage and that both electronic and ordinary flashguns can be operated. Four silicon photovoltaic cells (BPY 1 1 ) form a light sensor. Undoubtedly other types will do, too. The thyristor must be of a type with a very low firing voltage; the TIC 46 used here performs quite well. The circuit itself needs little comment: only that the polarity of the flash con- nection should be correct; the ‘plus’ Of course the circuit must be mounted in, on, or in the immediate vicinity of the kettle. sijuve should be connected to the centre pin of the connecting cable. The circuit can best be housed in a small, transparent plastic box. 1130 — elektor november 1975 tap-pow Thi; TAP-power circuit has been special^ designed for the TAP preamp system. It includes touch-controlled switches for turning the whole equipment on or off and for selecting the main power amplifiers or the headphone amplifiers, a power supply for the TAP pre-amp, simple headphone amplifiers and a disc preamplifier. NAND gates N 1 , N2 and N3, N4 (IC 4 = CD4001) make up two touch switches. Four LEDs are used to indicate the con- dition in which the system has been set; D2 = ON, D3 = OFF, D6 = headphones and D5 = power amplifier. Because of the difference between this circuitry and the rest of the TAP system, construction is much simpler: instead of a diode matrix only two flip-flops are used here. The power supply is split up into three sections: one for the touch switches, one for the rest of the TAP preamp and one for the disc preamplifier. The supply for the touch switches must stay in operation even in the ‘OFF’ condition, because it would not other- wise be possible to start the whole out- fit with the ‘ON’ touch switch. For this reason, the switch supply is drawn directly from the unstabilised supply via series resistor R15 and zener diode Dl. Integrated voltage stabiliser IC 3 stabil- ises the 10-V supply needed for the TAP pre-amp. This can be accurately ad- justed with preset potentiometer PI . As the maximum output current of this IC is only 150 mA, the external power transistor T1 is added. When the supply voltage is switched on with the ‘ON’ touch switch, the logic state prevailing at the output of gate N1 is ‘1’, while it is ‘0’ at the output of N2. Transistors T2 and T3 are therefore cut off, and the supply voltage becomes available at output C. When the ‘OFF’ panel is touched, logic levels at the outputs of N1 and N2 are reversed, with the result that T2 and T3 turn on. The potential at pin 13 of IC3 is therefore pulled down almost to zero, so that the internal output transistors in the IC are cut off. The voltage at output C drops to 0 and the TAP preamp is turned off. The flip-flop formed by N3 and N4 pro- vides a changeover between headphones and the main power amplifier. When the output of N3 is at logic ‘1’, transistors T5 and T6 turn on, switching on the headphone amplifier built around T7 and T8. This amplifier, including the associated components within the dashed rectangle in figure 1 , is dupli- cated on the board for the left-hand headphone channel. Both amplifiers derive their supply from the collector of T6.The output of N4 is at logic‘0’. Transistor T4 is cut off and relay Re is not' energised. The relay contacts, Figure 1. Circuit of the main power supply the TAP switches for on/off switching an< loudspeaker/headphone selection, and one o the headphone amplifiers. ip-power elektor november 1975 — 1131 Parts list for figure 1 Resistors: R1 5,R35 = 680 ft R16 = 0.68 ft R1 7 = 1 k R18 = 3k3 R19,R28,R31 ,R36 = 470 ft R20,R21 ,R22,R23 = 10 M R24,R26,R27,R29,R32 = 27 k R25 = 220 ft R30 = 10 k R33 = 6k8 R34 = 1 k5 PI = 1 k Capacitors: C18 = 2200 fJL/35 V C19,C23 = 220 /i/1 6 V C20 = 330 n C21 = 470 n C22 = 4/U7/1 6 V C24 = 100 Ji/26 V Sundries: Transformer = 240 V/16 V, 1 A (see text) Bridge rectifier = B40C 1 500 Relay Re = 1 0 V, 300 ft (see text) Semiconductors: D1 = 5V6/400 mW D2,D3,D5,D6 = LED D4= DUS T1 = BD 135 (cooled) T2,T6 = BC 177 (possib. TUP) T3,T5,T8 = BC 107 (possib. TUN) T4 = BC 517 T7 = BC 549 C, BC 109 C IC3 = /iA 723 IC4 = CD 4011 ■vhich switch the supply for the main Dower amplifiers on and off at the primary of the mains transformer for hese amplifiers, stay open. When the loudspeaker touch panel s touched the relay contacts close and the power amplifier is turned on: the tieadphone amplifier no longer gets a power supply because the logic ‘O’ at the output of gate N3 cuts off transis- tors T5 and T6. riie. disc preamplifier (figure 2) is the * same as was described in the April 1975 issue of Elektor. Power supply for the preamplifier is provided by the inte- grated stabiliser IC 2 . Points A and B are connected to the corresponding points in figure 1 . Construction Current consumption of the touch- switching circuit is about 30 mA in the ‘OFF’ position. In the switched-on state, the maximum consumption with headphone listening is about 100 mA (not counting the TAP preamplifier, of course!). Including the TAP preampli- fier, the maximum current consumption is 320 mA when the headphone ampli- fiers are on and the volume control is at maximum. Figure 1 shows six points at which the D.C. voltage can be checked. With the transformer secondary delivering 16 volts RMS and the TAP preamp not connected, the voltages at these points should be 20 V, 10 V, 12 V, 6.8 V, 1.8 V and 6 V respectively. The headphone amplifier delivers 2 V R.M.S. with the maximum input signal of 850 mV. Headphones with an im- pedance of 400 ohms or higher can be 1132 — elektor november 1975 tap-powei Parts list for figure 2 Capacitors: Cl, Cl 5 = 680 p Resistors: C2,C6,C10,C14 = 4/J7/25 V R1 ,R1 4 = 100 k C3,C1 3 = 2n7 R2.R13 = 1 M C4,C5,C1 1 ,C1 2 = 4n7 R3.R11 = 10 £2 C7,C9 = 470 n R4.R12 = 1 k2 C8 = 1 0 /i/1 6 V R5.R10 = 270 k C16 = 100 n R6,R9 = 150 k R7 = 56 k Cl 7 = 10 ... 22 yu/25 V R8 = 470 k Semiconductors: IC1 = SN 761 31 , /JA 739, TBA 231 IC2 = TBA 625 C Figure 2. Circuit of the disc preamplifiers, and external connections to the TBA 625C stabil- iser 1C from which they are supplied. Figure 3. Printed circuit board and com- ponent layout. ap-power elektor november 1975 — 1133 onnected to the output D. The value >f capacitor C23 is calculated for head- >hones with an impedance of 2 k. rransistor T1 must be adequately cooled; the power dissipation - and lence the dimensions of the heatsink leeded — depends on the transformer econdary voltage: Transformer Heatsink secondary area voltage (V RMS) (cm 2 ) 16* 50 18 80 It is often a good solution to use the case as a heat sink, with the transistor mounted on the outside. The pull-in voltage for relay Re is about 10 V. The contacts fnust be rated to make and break at least 250 V, and a current depending on the maximum drawn by the power amplifiers. For two 100 W amplifiers driving 4-ohm loads a relay with 8 A contacts is suit- able. To avoid relay chatter when a number of touch panels are operated at the same time, it is advisable to connect 1 n capacitors C a to Cd across each pair of touch contacts. A 100 n/400 V capacitor can be con- nected across the relay to prevent contact burning. The TBA 625C stabiliser IC delivers an output of 1 5 V. As this is the minimum acceptable voltage for the disc preampli- fier, it is essential that a Type C stabil- iser be used. A heat sink is not absol- utely necessary. A tantalum electrolytic capacitor should be used for Cl 7 to forestall any possible tendency to oscil- lation. Figure 3 shows the printed circuit board and the component layout for the TAP- power circuit. Except for the mains transformer, bridge rectifier, smoothing capacitor Cl 8 and relay, all the com- ponents are accomodated on one board. r Or Ol $ ® 3 $ In .'HhHF* Jc, Jg HP* HP • — IQs 25 — • •— niss — • ^ Hh B . ® HP* £ < HP* HP *c „ > HP* R35b H JJb " « R36« run. 'S' . . (L 3 ?r 1 1 1 1 § in C »C4 D II YM B c I I RE 73 ® « ® * ® **■ > -*■ ** A 9072 1134 — elektor november 1975 clamant clock part 1 Any horologist who keeps a digital clock in the same room as conven- tional clocks cannot but feel sad to see it sitting there, mute and reproachful amongst its more vociferous brothers, its only sound the feeble humming of the mains transformer. In this article we look at various ways of providing the digital clock with a voice, so that it can draw our attention to the fact that it is keeping time far more accurately than any mere mechanical clock. The main attribute lacking in a digital clock is the comforting tick which as- sures us that the thing is actually going. How many man-hours have been wasted waiting for the elusive change of that last digit? ‘Well I’m sure its been stuck at that time for more than a minute now.’ A clock with a seconds display or flash- ing colon alleviates these problems, but the hypnotic effect of such devices has been known to send people to sleep. No such problem exists with a tick, which informs us that the clock is work- ing without actually looking at it. The circuit The tick-tock sound of a conventional clock is produced by the balance wheel (or pendulum) and escapement, the tick and tock sounds having different pitch. The pitch of the sounds and the rep- etition frequency obviously depend on the physical construction of the clock. A grandfather clock will have a deeper, more leisurely tick than a travelling alarm. Electronic simulation of the sound is fortunately relatively simple. The waveform of the ticking is a damped res- Figure 1. Gyrator circuit to simulate tick-tock of a clock. Figure 2. P.C. board and component layout for gyrator circuit. R 1 X X R3 X R4 R6 R9 00 00 00 00 Jt -X CD CD ID to JT L— J CO 0- TUN T X C3 R5 R8 co CO cc JC v -X II b * 10 RS — — • R9 . r J I 1136 — elektor november 1975 clamant clock part 1 minute-counter units of hours X r 9(1) r 9(2) r 0U) r 0I2) 7490 :6 A B C 0 4 1 ( ► tens of hours r 9(1) r 9<2> R 0I1) R 0(2) a | (\| 7490 : 1 0 A B C D r - - r rn I clock V 0 6 si mi A B C D A B C D 7442 7442 0 1 2 3 4 5 01 234 56789 V ■ i* i S2 I I I alarm system clear 1/2 7473 :2 A A I — clock clear 1/2 7473 :2 B B \ 10 (ioii S3 alarm signal generator 1 __l 1 0 o— o 4015 4 The frequency of the sounds may be adjusted to suit personal taste by exper- imenting with the values of Cl, C2 and C4. Since C3 and the input impedance of the trigger input differentiate the trigger pulse, changing the value of C3 will affect the ‘crispness’ of the sound. $ P.C. Board A suitable printed circuit board already exists for the Minidrum gyrator, and the board and component layout (modified for use with clock) are given in figure 2. Alarm Clock One clock noise in popular demand by readers (though perhaps not first thing in the morning) is an alarm. It is a simple matter to add an alarm to a digi- tal clock (but unfortunately not so simple if the display is multiplexed). The alarm control circuit given in figure 4 is suitable for TTL clocks with parallel outputs (i.e. where the BCD outputs of the hours and minutes counters are available continuously and are not strobed). It was felt that an alarm set- ting accuracy of one minute was not necessary, so the smallest step provided in this circuit is 10 minutes. The circuit operates as follows: the portion of the circuit inside the dotted box is the alarm. The rest is the existing clock circuitry. The BCD out- puts of the hours and tens of minutes counters are decoded to decimal by the 7442’s. No decoding of the tens of hours is required as the truth table for this counter (table 1) shows. Outputs A and B are never both ‘1’ at the same time. The desired alarm time is selected by single-pole switches SI - S3. When the required time is reached three of the inputs of the four-input NAND gate go high. This allows the alarm signal con- nected to the fourth input to pass through the gate. The possibilities for the actual alarm sig- nal generator are endless. The simplest solution would be a fixed frequency os- cillator such as an astable multivibrator. There are however more interesting possibilities. The voltage-controlled multivibrator of figure 5 can be made to play a tune by connecting differing voltages sequentially to the control in- put. For a control voltage range of 2-5 V the frequency range covered is about 3 octaves. There are various methods of driving the oscillator. A simple circuit is shown in figure 6. This consists of a 7490 connected as a BCD decade counter, with its outputs con- nected to the VCO via presets. As the Table I HOURS A A B B 0 0 1 0 1 10 1 0 0 1 20 0 1 1 0 clamant clock part 1 elektor november 1975 — 1137 6 Figure 3. Photograph of the completed board. Figure 4. Circuit of an alarm control system. Figure 5. A voltage-controlled oscillator VCO that may be used to generate a tuneful alarm signal. Figure 6. Using the existing seconds counter in the clock to produce a varying voltage for the VCO. Since the outputs interact it is diffi- cult to tune this circuit to play a particular melody. Figure 7. This circuit may be used to make the VCO play a tune. Ten independent sequential outputs are produced, so each pre- set can be used to tune one note in the se- quence. Figure 8. Extension of the circuit of figure 7 to a 20-note sequence. Table I. Output of an arbitrary tens of hours counter as in figure 4. output states of the counter change so will the output voltage to the VCO. Of course the outputs change in a binary sequence so more than one output can be high at one time. Since the outputs interact it is difficult to set this circuit to play a particular tune. In addition the 1 Hz clock pulses are also fed in via R2 increasing the per- mutations still further. If one requires a circuit which can be set to play a particular tune then figure 7 is more suitable. Here the outputs of the 7490 are decoded with a 7442 to give ten independent outputs. These outputs go low in sequence as the counter goes through its cycle. All other outputs are high, reverse-biassing their respective diodes, so no current flows through their respective presets. Only the preset connected to the output which is low forms a potential divider with R 1 . This means that each note in the sequence can be tuned independently. This ten-note sequence can easily be ex- tended to twenty notes by the circuit of figure 8. In this circuit two decoders are driven by the 7490 and are switched in and out by the 1 Hz clock pulses to the counter. Thus, during the half-period when the clock pulse is ‘0’ the outputs of the 7490 are switched through the transfer gates (7400) to decoder A. The other transfer gates are disabled by the ‘O’ on their commoncd inputs, so their outputs are all ‘1\ This is an invalid in- put code for the 7442 so all its outputs are high. During the ‘1’ half period of the clock pulse the reverse situation occurs. Decoder B is enabled, whilst A is disabled. Decoder A thus controls the even notes 0, 2, 4, . . . in the sequence, whilst decoder B controls the odd notes 1 , 3, 5, .... Of course in this case, if an equal time span is required for each note then the clock pulse waveform must have a 1 : 1 mark-space ratio. The 7490 in all these cases can be the existing seconds counter in the clock. Another variation on the alarm theme can be obtained by a circuit which changes the rhythm of the tone se- quence, making it less monotonous. Such a circuit is given in figure 9. The dividers I to III are again part of the existing clock circuit. The operation of the circuit is as follows: counter II controls the pitch of the volt- age controlled multivibrator as in the circuit of figure 6, except that no ad- justment is provided for. The time at which the alarm sounds is again deter- mined by the alarm control circuit, as in figure 4. The rhythm variation is provided by gating the C output of counter I with the A output of counter 1138 — elektor november 1975 clamant clock part 1 III, and the B output of counter I with the B output of counter III. This has the following effects. Starting at a point in the timing cycle where counter III has just reset A 4 and B 4 are both ‘O’. The outputs of N1 and N2 are thus high so (assuming it is time for the alarm to go off and the outputs of N3 and N4 are high) the tone sequence controlled by counter III can pass through N5. After 10 seconds output A 4 goes high and the pulses from output C 2 switch the out- put of N2 between ‘O’ and ‘1*. The tone from the output of N5 is thus switched on and off at a 2.5 Hz rate. After 20 seconds output B 4 goes to ‘1’ whilst output A 4 goes to ‘O’. The output of N2 is thus high whilst via N1 output B 2 switches the tone on and off at a 5 Hz rate. After 30 seconds output A 4 again goes to M’ while B 4 remains at ‘1’. Outputs B 2 and C 2 therefore both affect the tone output. When either of these outputs is high the tone is off, and when both of them are low the tone is on. A timing diagram for these events is shown in figure 10. The top two wave- forms are the outputs B 2 and C 2 during >a 1 second interval of the sequence (this repeats every second). The other 4 waveforms are the tone outputs that occur for the four possible states of A 4 and B 4 . The audible effect is thus as follows: an uninterrupted tone sequence for 10 seconds, then a further 1 0 second in- terval of tone bursts and silence as in figure lOd, then 10 seconds as figure lOe and finally 10 seconds as in figure lOf, after which the sequence repeats. Of course, during each ten second period the frequency of the tone is being varied by the outputs of counter II. It should be noted that for all these alarm circuits a symmetrical 1 Hz squarewave is required from the output of counter II. This means that the 7490 (which consists of a divide-by-2 and a Figure 9. Circuit for generating an alarm sig- nal with variable pitch and rhythm. Figure 10. Timing diagram for the circuit of figure 9, showing the tone sequences for the four possible states of A4 and B4. Figure 11. Circuit to gradually increase the volume of the alarm signal if the sleeper does not awaken immediately. Figure 12. A complete alarm circuit incorpor- ating the ideas of the previous circuits. divide-by-five counter in the same package) must be connected with the divide-by-2 after the divide-by-5, as shown in figure 9. If an existing clock circuit is used this counter may be connected as a BCD decade counter (i.e. with the divide-by-5 after the divide-by-2). Some slight modification may therefore be necessary. Volume Control In order not to awaken the sleeper too harshly it is a simple matter to arrange a volume control so that the alarm tone starts at a low level and gradually be- comes louder and louder until it is switched off. This is achieved by the circuit of figure 1 1. The counter shown is the minutes counter (i.e. the one that drives the minutes display). Since the alarm can only be set in units of ten minutes, the alarm will sound when the tens of minutes have just changed to the required number and the minutes coun- ter is reset. Outputs A to C of the minutes counter are thus at ‘O’, so T2 to T4 are turned off. The alarm tone is applied to the base of T1 via R1 and switches this transistor on and off causing a signal from the loudspeaker. Since there is a 390 £2 resistor (R2) in series with it the tone is not very loud. After 1 minute the A output of the counter goes to ‘1’, switching on T2 and thus connecting R3 in parallel with R2. The tone thus becomes louder. After 2 minutes output B becomes ‘1’ while A becomes ‘O’. R4, which is smaller than R3, is paralleled with R2, so the tone becomes louder still. After 3 minutes outputs A and B are ‘1’, and after 4 minutes output C becomes ‘1’, by which time the tone is quite loud. Output D is not connected to this sys- tem. If the sleeper has not awoken after 8 minutes output D will become ‘ 1 ’ and can be connected to set off a small explosive charge underneath the bed. A less drastic cure for the deep sleeper is to connect an additional transistor to output D with a 56 12 resistor in series with its emitter. The complete circuit of an alarm system is given in figure 12. Everything within the dotted box is the alarm circuit, whilst everything outside is the existing clock circuitry. This differs slightly from the circuits discussed in that a HEX-inverter replaces the five-input NAND-gate in the alarm control circuit. This has open-collector outputs, so the outputs may be joined to perform a wired-OR function. In this circuit the additional transistor T9 is shown con- nected to output D5 for the extra loud alarm signal. A suitable printed circuit board and component layout for this alarm are given in figure 13. Time Signal Generator Provision of a ‘six pips’ time signal every hour is a relatively simple matter clamant clock part 1 elektor november 1975 — 1139 no r- I sec B? b C2 C A 4 » 0 04 • 0 I d A4 • 1 84-0 tone 1 tone 2 tone 1 Peuse tone 2 e A4 0 04 - 1 f I A 4 • 1 B4 * 1 I , I tone 1 tone 2 • 1 1 1 1 i 1 i ! I 1 ! l l 1 l 1 1 1 1 i 1 1 1 i 1 1 1 1 1 tone 1 1 1 lone 2 1 i ■ 1 MIS 11 minute pulses [>° a in Bin 7490 : 10 B 5V © fl] T 4 T3 T2 LS 8ft alarm signal T 1 4015 11 I X R3 CJ R4 a R5 R2 Cl § 0 cc O CN § n ro Components list for figure 12 Resistors: R 1 = 39 k R2 ... R5 = 47 k R6 = 18 k R7,R12,R13= 1 k R8,R1 1 = 12 k R9,R1 0 = 1 M R14,R18 = 390n R15 = 180 £2 R16 = 120 D. R17 = 56 n Capacitors: Cl ,C2 = 1 n5 Semiconductors: T 1 ... T9 = TUN D1,D2 = DUS IC's: IC1 = 7401 IC2,IC3 = 7442 Switches: 51 = single pole 6-way 52 = single pole 10-way 53 = single pole 3-way (decimal coded thumbwheel switches suggested) x 8i L J <015 12 | 1140 — elektor november 1975 clamant clock part and a suitable circuit is given in fig- ures 14 (block diagram) and 15. The portion of the circuit outside the dotted box in figure 15 is the existing seconds counter in the clock. The circuit works in the following manner: the inputs of gate 1 are connected to the outputs of the tens of minutes, minutes, tens of seconds and seconds counters corresponding to the time 59 minutes 55 seconds. When this time is reached the inputs of gate 1 will all be high, so the output will be low. At any other time at least one input must be low, so the output will be high. Nor- mally therefore, the Q output of IC2 is low, so the output of IC4b is high blocking the oscillator IC4a (which will be dealt with later), whilst the Q output is high, holding the -r 6 counter IC3 in Figure 13. P.C. board and component layoui for the circuit of figure 12. Figure 14. Block diagram of a time-signal gen- erator. Figure 15. Complete circuit of the time-signal generator. T4 1 Hz pulses Flipflop gate 2 4015 14 LS 8ft clamant clock part 1 elektor november 1975 — 1141 Components list for figure 15 Resistors: Capacitors: R1 = 220 k Cl = 470 n IC's: R2,R5 = 2k2 C2 = 1 /i, 6 V IC1 = 7430 R3,R4,R6 = 1 k IC2 = 7473 R7 = 100 £2 Transistors: IC3 = 7492 PI ,P2 = 1 k Tl ... T4 = TUN IC4 = 7413 the reset condition. On the negative- going edge of the incoming seconds pulse at 59 minutes 55 seconds the out- put of the seconds counter will assume the condition ‘5’, i.e. outputs A and C high. The output of gate 1 will go low, clearing IC2 so that the Q output goes low and the Q output goes high. IC3 may now count the incoming sec- onds pulses. However, due to the propa- gation delays through the seconds counter, IC1 and IC2, it will not count on the abovementioned negative-going edge, as this has already disappeared be- fore the counter is enabled. However, the negative-going pulse is differentiated by Cl and R3 (neglecting R1 and the base resistance of Tl), and turns off T1 for about 100 ms. This takes pin 1 of IC4 high, and since pins 4 and 5 are already held high by the Q output of IC2 the oscillator will be gated through it providing a 1 kHz tone burst of 100 ms duration. On each negative-going edge of the five subsequent second pulses IC3 will count and the oscillator will provide a 100 ms tone burst. On the fifth pulse the D out- put of IC3 will go high, and on the sixth pulse the D output goes low, clocking 1C2, so that its Q output goes high and its Q output goes low. This disables the oscillator and holds the counter (IC3) in a reset condition so that it can count no further seconds pulses. This condition obtains for a further 59 minutes 55 sec- onds until it is time for the next signal. The circuit thus produces six pips every hour, starting with the first pip at 59 minutes 55 seconds and terminating with a pip exactly on the hour. Of course, this circuit produces pips of equal length, whereas the last pip of a radio time signal is longer than the pre- ceding five. An alternative circuit, which produces this type of signal, was de- scribed in Elektor July/ August 1975. Oscillator and Amplifier The oscillator is a simple single time COUNT D OUTPUTS C B 0 0 0 0 1 0 0 1 2 0 1 0 3 1 0 0 4 1 0 1 5 1 1 0 0 0 0 0 Table II. Truth table for the 7492 connected as a divide-by-6 counter. 1142 — elektor november 1975 clamant clock part ‘ constant multivibrator based on the 7413 which is a dual 4-input NAND Schmitt Trigger. Assuming the output of IC4a is initially high then C2 will charge through PI until the voltage across it reaches the threshold of the Schmitt trigger. The output will then go low and C2 will discharge through PI until it falls below the threshold, when the output will go high again. Because of hysteresis the negative-going threshold is below the positive-going threshold, so the frequency of the oscil- lator is determined by the time taken to charge and discharge C2 between these points, which is of course dependent on the time constant P1C2. The oscillator frequency can therefore be varied by PI. With C2 = 1 ju and PI set to 330 £2 the frequency will be about 1 kHz. Altering PI also changes the mark-space ratio of the waveform, but this is unimportant in this application. The other gate in IC4 is used to gate the oscillator output into the amplifier, consisting of T2 to T3. This is a simple switching amplifier, as only square waves are being dealt with. In the quiescent state only T2 is turned on so the current drawn is only about 7 mA. P.C. Board The track pattern and component lay- Figure 16. Board and component layout for the time-signal generator. out of a board suitable for the time- signal circuit is given in figure 16. Note that R4 (shown dotted in figure 15) is a precaution against power supply ripple appearing at the loudspeaker output. Depending on the power supply it may or may not be necessary. lie detector / brake lights for model cars elektor november 1975 — 1143 J. Jacobs lie detector This lie detector works in the usual manner by measuring skin resistance and therefore is no innovation, but in com- parison with the designs popular some years ago it offers a number of useful im- provements. In the circuit the advantages of opamps have been turned to full use. The detector operates fully symmetri- cally, and therefore two batteries are required. The voltage across the elec- trodes according to local regulations in some countries, may not be higher than 2 V so a reference voltage of no more than 1.2 V is applied to the input of the measuring bridge. Since the resistance of the human skin is generally 50 k or less, the voltage across the electrodes will be at maximum 0.6 V. The set-up of the measuring bridge has the additional advantage that the reference voltage is independent of the battery voltage. To obtain a sufficiently high sensitivity the total amplification in the detector should preferably be greater than 1 00,000 times. Therefore a second opamp was added, which brings the overall amplification to about 250,000 times. With the double potentiometer of 500 k the amplification R. Zimmer can be adjusted from 0 to the above-mentioned maximum. The 100 k potentiometer serves- to adjust the sensitivity of the moving coil meter; therefore the input bridge is first brought completely out of balance to the one side and then to the other by means of the 100 k potentiometer, whilst the positive and negative deflection of the meter is adjusted to maximum. After- wards the adjustment potentiometer can, if required, be replaced by a fixed re- sistor. brake lights for model cars This circuit performs two functions: when the supply voltage to the motor of the model car cuts out, the car will not stop abruptly but will continue over some distance and during that time two LED’s will light up and function as brake lights. Thus a very realistic effect is obtained. The circuit is extremely simple. As long as the car is under power, there is a voltage across the motor (M), the polarity of which is indicated in the diagram. Capacitor Cj and (via diode D) also C 2 are now charged. When the voltage cuts out, C\ discharges across M and C 2 discharges via the two LED’s, resistor R, and motor M. If braking is the result of a short-circuit of the supply voltage, both capacitors dis- charge via the short-circuit connection; in that case the LED’s burn somewhat brighter. The value of resistor R can be calculated with the following simple formula: r = 12 - 2 V lhd Iled Usually a value of about 560 12 will be suitable. 1144 — elektor november 1975 universal ota pll Performance Data Narrow-band FM reception (VCO free-running frequency approxi- mately 10.7 MHz) Capture and hold ranges Capture Hold Input 160 pV 190 kHz 540 kHz Input 1 .6 mV 250 kHz 4 MHz Input 10 mV 400 kHz 10 MHz AM Suppression Input 1 60 pV >60 dB Input 100 pV • >40 dB Sensitivity Deviation = ±3 kHz Minimum input = 3.2 pV With input = 4 pV : output = 700 mV, signal/noise ratio = 40 dB Wide-band Stereo FM reception (VCO free-running frequency approxi- mately 455 kHz) Capture and hold ranges With minimum input (12.6 pV): Capture range » hold range ^400 kHz Sensitivity (Deviation = ±30 kHz) Minimum input =12.6 pV With input = 500 pV: output = 360 mV, signal/noise ratio >40 dB Elektor has taken a lead in drawing attention to the possibilities of the PLL (Phase Locked Loop), and has devoted a number of articles to designs incorporating this versatile circuit, as well as to explaining the principles of different applications. The Universal OTA (Operational Transconductance Amplifier) PLL described here is a printed-circuit module which can form the nucleus of many different types of receiver. Most of the integrated PLLs now avail- able for FM receivers are expensive and require a 24-volt power supply, which makes them inconvenient for either portable or car-borne use. This universal PLL works quite happily on a 5-volt supply, but the working voltage may be determined in practice by the needs of a MOSFET RF amplifier, which can re- quire 9 volts. This, however, is easy to provide in battery-powered portable equipment, and it also leaves a margin for stabilisation when running from a 1 2 V car supply. Sensitivity on a 10.7 MHz FM input with 3 kHz deviation is 3.2 pV for a 700 mV audio output. For a receiver for the 144 to 146 MHz band, the aerial signal is pre-amplified and converted to a band from 10 MHz to 12 MHz by a stable 134 MHz mixer- oscillator. Any signal in the 2 MHz-wide band can then be tuned in by adjusting (with a potmeter) the frequency of the voltage-controlled oscillator incorpor- ated in the PLL. Figure 1 shows a block diagram of the arrangement. The 134 MHz local oscil- lator will normally be a crystal oscillator of lower frequency in conjunction with a multiplier. Assuming the combined gain of the pre-amplifier and the mixing stage to have the easily-achievable value universal ota pll elektor november 1975 — 1145 of 20 dB, the overall receiver sensitivity for the quoted audio output of 700 mV will be some 0.3 /iV, which is better than that of most commercial receivers for this band. For reception of wide-band broadcast FM signals, the unusual arrangement of a double superheterodyne, with a second IF as low as 455 kHz, is used (see figure 2). The low modulation index of a stereo FM signal makes de- modulation with a good signal-to-noise ratio difficult to achieve, and even in the best (and most expensive) receivers this is seldom above 50 dB on strong sig- nals. With this very low second IF, 60 dB is achieved. Yet again; what is a PLL? For those who have not yet had an opportunity to familiarise themselves with the basic concept of the phase- locked loop, the essential features of this circuit can be repeated. The key element is a voltage-controlled oscillator. When the loop is used in a receiver, this oscillator is automatically synchronised with the carrier of the incoming signal. The other elements in the loop are sub- servient to the main purpose of keeping the oscillator synchronised. In practice, this is done by maintaining a constant phase difference between the incoming c J OTA PLL I 6029 1 n o| AF Figure 1. Block diagram of a receiver for narrow-band FM transmissions in the 144 MHz-146 MHz amateur band, with a fixed-frequency mixing oscillator and band- spread tuning by varying the intermediate frequency. signal and the oscillator output: hence the term ‘phase-locked loop’. By definition, the oscillator is voltage- controlled. So if the incoming signal is frequency -modulated, the control volt- age applied to the oscillator to keep it synchronised becomes, of itself, the demodulation of the incoming signal. As liiil 1146 — elektor november 1975 universal ota pll a method of detection, this has import- ant advantages over other methods in terms of better rejection of interfering signals, lower distortion, and better signal-to-noise ratio. Circuit description The input is fed in across resistor R1 (figure 3). The value of this resistor must be selected to give correct matching to the preceding mixer stage, and suitable values will be given in later articles describing particular appli- cations. Transistors T1 and T2 form a differential amplifier with an asym- metrical input, while T3 and diodes D1 and D2 stabilise the current flowing through T1 and T2. The two collectors of the differential amplifier are con- nected through capacitors C4 and C5 to the two differential inputs (2 and 3) of the CA3080 operational transconduc- tance amplifier 1C1 . The use of both in- puts in this fashion gives an extra 6 dB gain without impairing stability and also facilitates the operation of the limiting diodes D3 and D4. In addition to receiving the RF (or IF) signal at the differential inputs (pins 2 and 3)-, IC1 is fed via pin 5 with the output of the voltage-controlled oscil- lator formed by T4 and T5. Although this oscillator is described as voltage- controlled, it should more properly be called current-controlled, the current being regulated by T6 and T7 in the emitter leads of T4 and T5 respectively. It can, however, be said without too much straining of the truth that the commoned bases of T6 and T7 are volt- age-controlled from the output (pin 6) of IC1. In the foregoing description the path of the loop has, in effect, been followed in the reverse direction. Recapping and going the correct way round: the DC component of the signal at pin 6 of the phase-comparator IC1 is amplified by T6 and T7 and controls the frequency of oscillator T4 + T5. As in all FM detectors, AM rejection is important. The CA 3080 has good AM rejection at low input-signal levels, but is less good at higher levels. These higher levels, however, are taken care of by the clipping diodes D3 and D4, which begin contributing to AM rejection when the peak-to-peak signal between pins 2 and 3 of IC1 exceeds 1 volt. Capacitor Cl 1 is one of the components whose value influences the VCO free- running frequency (455 kHz in the broadcast FM receiver, or about 10 MHz in the narrow-band FM receiver) so its value is quoted for particular appli- cations (see Table). When the receiver is tuned by varying the VCO frequency, as in the narrow-band FM receiver, pot- meters PI and P2 come into play. When the working IF frequency is fixed, these potmeters can be used for preset adjust- ment. 6029 3a * see text universal ota pll elektor november 1975 — 1147 Figure 2. Block diagram of a double super- heterodyne for stereo FM reception, with intermediate frequencies of 10.7 MHz and 455 kHz. Figure 3. Circuit of the Universal OTA PLL. Table: Values of R1, R14, R24, C9,C11 and C14 for specific applications. Values of R1, R14, R24, C9, Cl 1 and C14 for specific applications Mode of operation (all FM) Supply voltage R1 R14 R24 C9 C11 C14 Type of transmission Intermediate frequency Minimum input* Wide band mono 10.7 MHz 160 /iV 9 330 £2 1 k 150 £2 100 p 10 n Narrow band 10.7 MHz 3.2 /iV 9 330 £2- 2k2 47 k o £2 — 220 p 10 n Wide band mono 455 kHz 400 /iV 9 _ 47 k 2k2 560 p 2n2 10 n Narrow band 455 kHz > o CM 9 3k3 47 k 82 £2 560 p 2n2 10 n Wide band stereo 455 kHz 500 9 — 47 k 2k2 220 p 2n2 — Wide band stereo 455 kHz 200 jUV 12 — 47 k 2k2 220 p 2n2 * At the PLL! (— = omitted) The low-pass filter which removes the unwanted ‘sum’ frequency (oscillator plus input signal) is formed by C8, C9, R14 and R16. As the values of these resistors also effect the VCO free- running frequency, they have to be sel- ected carefully for each application. In practice, R16 is given a fixed value of 68 k£2 while R14 is specified for each application. This also applies to the feedback resistor R24 which controls the gain of the output audio ampli- fier T8 and T9. Resistor R28 and ca- pacitor Cl 4 provide de-emphasis. It will be seen that the whole of the DC com- ponent at the output (pin 6) of the phase comparator is passed to the VCO: this helps to ensure a large ‘hold range’ for the loop. Detailed descriptions of applications of the Universal PLL will be given in later articles, but the two which have already been mentioned can be briefly discussed here. <5> D5 <5> d> i — x — -L — i — r X R,7 P = R,9 n oeX £ lOOn t T ? 1 JLT R23 1 < \ 1 — — , " \ I l L / . R 18T 1 R20| d j£ > < » LI 470/JH 12V P1 JL Ik C 1 2 P2 -L 100ft "'"-'l -U o* o 6029 3b * see text Resistors: Parts list R1 ,R1 4.R24 = see table R2.R4.R1 1 ,R1 2,R28 = 4k7 R3,R8,R1 5,R1 7,R1 8,R19,R20 = 1 k R9,R10,R23 = 10 k R5.R6 = 560 £2 R7 = 1 00 £2 R27 = 100 k R13,R22= 220 k R1 6 = 68 k R21 = 470 k R25.R26 = 2k2 PI = 1 k P2 = 1 00 £2 Capacitors: Cl ,C2,C6,C10 = 100 n C3 = 470 JU/1 6 V C4,C5 = 22 n C7 = 47 /i/1 6 V C8,C1 3 = 470 n C9,C1 1 ,C1 4 = see table Cl 2 = 47 M/10 V Cl 5= IOO/i/6 V Cl 6 = iom/io V Semiconductors: T1 ... T7 = BF 494 T8 = BC 547 T9 = BC 557 Inductor: IC1 = CA 3080 LI = 470 JUH D1 ... D6 = 1 N 41 48 1148 — elektor november 1975 universal ota pi Narrow-band FM receiver In narrow-band FM systems, noise always tends to be a problem because the modulation index (the ratio of the maximum deviation to the highest modulation frequency) is by definition low, but the good noise performance of a PLL demodulator goes a long way towards overcoming this handicap. The limiting sensitivity of the Universal PLL, when used in a narrow-band FM re- ceiver, has already been stated to be 3.2 jiV, not counting the gain of the RF and mixer stages preceding it. With an input of 4 /iV — slightly above the limiting value — the signal-to-noise ratio is 40 dB. The principle of using a crystal-con- trolled fixed-frequency local oscillator, and tuning the IF with the VCO, offers a very simple and effective form of band-spreading. Stereo FM receiver FM sound broadcasting has a maximum deviation of 75 kHz, which gives a modulation index of 5 on mono trans- missions having a 15-kHz audio band- width. With a stereo transmission, the maximum modulation frequency is 53 kHz, but the effective bandwidth of Figure 4. Printed circuit board. Figure 5. Component layout of the universal OTA PLL. the composite stereo signal is greater than this, and in practice the modu- lation index works out as low as 0.6. This means that, ‘other things being equal’, stereo reception has a signal-to- noise ratio 20 dB lower than the same stereo transmission reproduced in mono. These problems are discussed more fully in ‘Modulation Systems’ (Elektor 2, p. 246 and Elektor 3, p. 454). A PLL detector can help considerably in this situation, because it can easily be made to work on a very low second IF. The output of an FM demodulator is proportional to the quotient of the de- viation and the working frequency. If, therefore, the working (intermediate) frequency is as low as 455 kHz, the out- put will be considerably greater than with the normal intermediate fre- quency of 10.7 MHz, while the noise will be approximately the same in both cases. In theory, a ‘normal’ discrimi- nator could be made with this working frequency and the usual 75-kHz devi- ation, but it would be difficult to make it work satisfactorily. A PLL demodu- lator, on the other hand, lends itself readily to working with these para- meters and enables a 60-dB signal-to- noise ratio to be obtained. elektor november 1975 — 1149 tv test pattern generator A television pattern generator is one of the most useful TV service aids. It simplifies checking of the video stages, adjustment of picture ge- ometry, and perhaps most important, setting up of convergence in colour receivers. Using logic IC's for the generation of the test pattern allows the construction of a simple and reliable circuit, and the design given here is based on the 74 series TTL logic family. The test pattern generator produces the well-known dot and crosshatch patterns. In the crosshatch mode a number of horizontal and vertical bars are displayed on the screen, whilst in the dot mode only the crossing points of these bars are displayed, thus producing an array of dots. Building up the video signal The number of bars in the display has certain constraints placed upon it by the nature of the television picture. This is composed of a raster of 625 lines. Since the horizontal bars are produced by dividing down the 15625 Hz line frequency digitally, it follows that the ratio (625 : number of bars) must be a whole number, as it is not possible to obtain a non-integral division ratio digitally, and if it were the pattern would move anyway. Since 625 = 25 2 then 25 is a convenient number of bars. One of these is lost during the field blanking interval, so only 24 are in fact displayed. Since the ‘boxes’ formed by the bars should ideally be squares rather than rectangles this determines the number of vertical bars. The aspect ratio of a television picture is 4 : 3, so the number of verti- Parts list for figures 1 and 6 Resistors: R1 = 1 k R2,R3 = 470 £2 PI = 470 Hlin. P2 = 1 k lin. Capacitors: Cl = 1 n5 C2 = 220 p C3 = 220 n/250 V IC's: IC1 = 7400 IC2 = 7413 IC3,IC4 = 7490 IC5 = 7402 Figure 1. Circuit of the video generator section. cal bars is 24 x 4 or 32. The oscillator which produces the vertical bars runs at a higher frequency than line frequency (since there are several picture elements along each line). The circuit can conveniently be divided into two sections. The video generator, which produces the actual pattern, and a synchronising unit which produces the field and line sync pulses and also pro- vides the timing for the video generator. The circuit of the video generator is given in figure 1 . The vertical bar gener- ator SI is a NAND Schmitt trigger connected as an astable multivibrator. Since the TV line frequency is 15625 Hz and there are 32 vertical bars it follows that the frequency of this astable must be 500 kHz. PI provides some adjust- ment so that the number of lines can be varied slightly. This oscillator is synchronised by line sync pulses. Each line sync pulse turns on Tl, grounding pin 5 of SI and momentarily blocking the oscillator. When the line sync pulse finishes Tl turns off and the oscillator restarts. This ensures that the pulses which make up the vertical bars occur at the same point along every line of the TV picture, as otherwise a random pattern would result. 1150 — elektor november 1975 tv test pattern generato tv test pattern generator elektor november 1975 — 1151 Figure 2. Oscillogram of the V signal at the output of N1. Figure 3. Timing diagram for the generation of the H signal. Figure 4. Oscillogram of the H signal. Figure 5. Circuit of the sync generator, showing connections to the video generator. Figure 6. P.c. board and component layout for the video generator. Figure 7. Photograph of the completed video generator. The output of the astable has substan- tially a 1:1 mark space ratio. This would, if used as the video signal, pro- duce black and white vertical bands of equal thickness. However, for the purposes of the pattern generator very narrow bands provide more information about the state of the video stages of the TV, since a narrow band requires a shorter pulse length and hence a greater bandwidth. Accordingly the output of the astable is differentiated by C2 and R3, and the spiky pulses are fed into a second Schmitt trigger to square them up again. This also inverts the signal, so it is in- verted a second time by N1 to appear in the correct sense. Figure 2 shows the vertical signal V as it appears at the out- put of Nl. The absence of pulses where the sync pulses occur can be clearly seen. The pulse length of the V signal is about 200 ns. Line sync pulses at the collector of T1 are also counted by IC3 and 1C4, which are 7490’s connected as divide-by-five counters. Output D of IC4 is therefore a pulse train at 1/25 of line frequency. The timing diagram for this division is shown in figure 3. Waveform V is the line sync input. Waveform 4 b’ is the D output of IC3, and waveform ‘c’ is the D output of IC4. However, this waveform cannot be used directly as the horizontal video signal, as the pulse length is equal to 5 line periods, which would make the horizontal bars too thick. For this reason it is ‘NANDed’ with waveform ‘b’ in N2 and then inverted by N3 to produce waveform 4 d* (H). This has a duration of 64 /is or one line period. However, due to inter- lace each horizontal bar will actually have a thickness of two lines. Figure 4 shows an oscillogram of the H signal. To produce the complete video signal the H and V signals must be summed. To produce the crosshatch pattern the horizontal and vertical signals must be ‘OR-d’ together, as there must be a bar when vertical or horizontal pulses are present. For the dot pattern, which corresponds to the crossing points of 1152 — elektor november 1975 tv test pattern generator •C «Q C3 C3 Hh* HH • — r~wn — • nnnnnn IC 6 UOOOUU'UTJ J 1 £ I . »-||^ • — cio— • ® • © • (3) 74404 Parts list for figures 5 and 7 Resistors: Capacitors: Semiconductors: R1 = 270 n Cl = 10 n IC1 = 7413 R2= 27 k C2 = 820 p IC2 - IC5 = 7490 R3 = 18 k C3 = 220 n IC6 = 74123 R4 = 39 k R5= 10k PI = 1 k lin. (part of video generator) P2 = 100 n preset C4 = 33 n D1 - D4 = DUS the horizontal and vertical bars, the pattern must appear only when horizon- tal and vertical information are present. The' H and V signals are thus ANDed together. These functions are performed by N4 and N5 respectively, and SI selects the pattern. N6 and S2 provide the option of a positive or negative pattern i.e. white pattern on black back- ground or black pattern on white ground. Note that peak white corre- sponds to logic ‘O’. It is possible to use this circuit as it stands without any additional circuitry. This is accomplished by tuning the set to a station so that sync pulses are available from the transmission. The circuit may be triggered by picking up line flyback pulses from the line output transformer using a pickup coil. The dimensions of this coil are not at all Figure 8. P.c. board and component layout for the sync generator. Figure 9. Photograph of the completed sync generator. critical, and several turns of insulated connecting wire a few cm diameter should prove suitable. The video signal is then taken from PI via C3 and is in- jected into the video stages of the TV. PI adjusts the video level so that the sig- nal does not interfere with the synchronisation of the set. A more elegant solution is to employ a built-in sync generator, the circuit of which is given in figure 5. Again a Schmitt trigger operates as an astable multivibrator, this time at a frequency of 250 kHz. The divide-by-two stages of four 7490’s are used to divide this down to the line frequency of 15625 Hz. The 50 Hz field sync pulses are pro- duced by taking the output of the third divide-by-two stage (31250 Hz) and feeding it back through the divide-by- five stages of the four 7490’s. Since the field and line sync pulses must have pulse lengths of about 250 /is and 4 /is respectively the 50 Hz and 15625 Hz outputs are used to trigger the two halves of a 74123 dual multivibrator, with appropriate time constants. The line sync pulses are used to trigger the video generator, and are also mixed with the field sync pulses and the video signal using the diode-resistor mixer network. Note that the output capacitor of the video generator is replaced by D4 in this circuit. The video output is taken from point B, and may be injected directly into the video stages of the TV set. Alternatively, the VHF/UHF modu- lator for the TV-tennis (described else- where in this issue) can be used. Construction A printed circuit board and component layout for the video generator are shown in figure 6, and for the sync generator in figure 8. Photographs of the completed boards are shown in figures 7 and 9. with a pencil point elektor november 1975 — 1153 W. Schmidt with peneil point 4any electronics enthusiasts look on older removing as a loathsome job. This s especially true of printed circuit >oards with narrowly-spaced conductors. Pilings which often happen when one is rying to desolder are: The solder forms bridges between the conductors. Blobs of solder drop off the board. )e-soldering tools or wicks are available ommercially, but there is no need to ay out that kind of money. Any work- hop toolbox should yield a really cheap evice which will do the trick - a pencil. Spelling pencils with long leads of 2B >r B hardness are particularly suitable e.g. clutch pencils). To remove solder rom a hole, the solder must be heated nth a soldering iron until it melts figure 1 ). The next step is to stick the >encil point in the hole, and take away he iron (figure 2). Where the pencil sad touches molten solder, the solder jumps’ away, because of its surface ension, and the hole is cleared of solder figure 3). i similar method can be used for get- ing rid of bridges of solder between racks. To do this, the pencil point is lid flat on the molten solder between he tracks. ung uno Mm :uno 1154 — elektor november 1975 markei Hall effect 1C Special features of a new Milliard Hall-effect integrated circuit, type TCA450A, include: small physical size, wide operating voltage and temperature ranges, high sensi- tivity, low offset flux, and self balancing. It can therefore be used to advantage in the measure- ment of magnetic field strengths in small areas or gaps. The function of the TCA450A is to translate information about the polarity and strength of a mag- netic field into a differential out- put current. The device is mono- lithic and consists of a silicon Hall-effect element and two as- sociated integrated amplifiers encapsulated in a miniature low profile plastic package. Typical applications include the provision of isolated current sensing and control in high cur- rent applications, contactless and highly-reliable electronic switching, sensing and control in electromagnetic systems where the field strength must be main- tained at a precisely determined level, the conversion of magnetic quantities into proportional cur- rents and the detection and pos- itional movement of rotating shafts. Brief Min.Typ.Max. Data Supply voltage 4 8 16 V Magnetic sensitivity of Hall element - 0.4 — V/T Voltage gain of amplifier - 15 — Mutual conduc- tance of amplifier — ±240 — mA/V Offset flux den- sity in balanced condition - ±25 mT Mullard House, Torrington Place, London, W.C. 1. C.R.T. probe attachment A new probe attachment has been introduced by Brandenburg Limited for use with the company's direct-reading high- voltage meters. The beryllium- copper attachment which screws into the existing h.v. probe unit, is designed to be slipped beneath the anode connection on the c.r.t. Brandenburg Limited, High Volt- age Engineering Division, 939 London Road, Thornton Heath, Surrey, CR4 6JE. New transistor for switched mode power supplies The latest addition to the Mullard range of transistors for high- frequency switched mode power supplies operating direct from ‘rectified mains’ inputs is type BUX82. It is intended for use in 400 W push-pull or 100 W to 200 W single-ended circuits. Together with other types in the same series, the BUX82 will not only operate satisfactorily at the ‘rectified mains' level, but will also accommodate the ±10% voltage variations regularly ex- perienced on mains supplies. To meet these requirements, the device has an open base collector-emitter rating of 400 V and a collector breakdown rating of 800 V (Vre = 0). Th e d.c. an d peak collector current ratings are 5 A and 8 A respectively. Fast switching characteristics not only minimise switching losses, but also facilitate high-frequency (25 kHz to 50 kHz) operation. Mullard House, Torrington Place, London, W.C. 1. m •W < e ' *> XX a\c* A6^ <0^ A > O c® ov 9 o\\N e V 6 ; e®®< t I'" - n< 1 , y,o° y-.e®'' ,*\® v.a'J® e'' / , lo^V ** vo’Vc** !e* 0 0- o'* e \*. , 0 < * vN'" Lc- ^S« s 'V' c, > *<>< u v > , 0 o® °v° o' * ® .a^S q^ xX e \e c ^ . ^ 0 \S^ vA°* 6 ^ v.o^ ^ \e^° e a v o<0 .XX<° <® v\e^ vaC V «(\S v ° dV * K ,„ »9°' c®o^ e ®° 3®") S O® '* V* xceX cO market elektor november 1975 — 1155 Range of Coiled Cables Available from Lemo Lemo (UK) can now supply a range of coiled cables, terminated or unterminated. Up to five con- ductors can be ordered, in a variety of uncoiled (maximum) lengths, and these can be cither telecommunications light-current flexibles or with mains-carrying flex in the cores. Outer insulation can be either p.v.c. or rubber, with the conductor insulation following suit. Lemo (UK) Ltd, 6 South Street, Worthing, Sussex BN 1 1 3AE. M-Tron industries establishes international division M-Tron Industries of Yankton, South Dakota, has formed an International Division to sell their crystals to the overseas market. The new international division will be located at 2200 Shames Drive, Westbury, L.I., New York 11590. Telex 961474. M-Tron Industries manufacture a wide line of quartz crystals. Pro- ducing over 10 million crystals a year, they are the number one manufacturer of CB and monitor crystals in the United States. Combined C-MOS and bipolar relay driver package The MM74C908/918 Dual High Voltage C-MOS driver consists of two C-MOS “NAND” gates driving a bi-polar emitter-follower Darlington to achieve high current drive and high voltage capabilities, while having the very low input- current characteristics of complemcntary-metal-oxide. The MM74C908/918 specifi- cations are at a min. 30 V break- down voltage and an output current range between 250 mA and 350 mA. However, this com- ponent is aimed at the telecom- munications market and was specifically designed to replace high voltage telephone relay drivers. Therefore, an improved version for this usage will be specified at 56 V min., packaged in a 14-lead, 2.5 Watt configur- ation. The main advantage of this new C-MOS High Voltage Driver is its nil power consumption - just leakage current in the stand-by- mode, while. a conventional telephone relay driver in the same mode uses about 10 to 20 mA. The dual high-voltage C-MOS drivers will be available in two different versions, the MM74C908N 8-pin moulded dual-in-line package and the MM74C918N 16-pin moulded dual-in-line package. National Semiconductor, The Precinct, Broxhourne, Herts. EN10 7HY. 'Switchmode' power transistors Motorola have just introduced the switchmode series of power tran- sistors. Designed for high-voltage power switching applications, the first devices in this series are designated 2N6542 to 2N6547 and are n-p-n triple-diffused sili- con transistors. Before these devices were introduced, designers of power equipment had to use transistors that were often only specified for resistive loads at room temperature. Unfortunately, in real life things are seldom so simple and, consequently, the designer was often faced with the task of using power devices at high temperatures and with reactive loads without sufficient information as to how the transis- tors were likely to perform under these conditions. Featured in the data sheets for these devices are all the significant specifications for high tempera- ture use Oc = 100°C) and for secondary breakdown under base forward biased and base-reverse- biased conditions. Dynamic voltage capabilities (sus- taining voltages) are given for v CEO (SUS) a nd V CEX (SUS)- Furthermore, V^EX (SUS) mi™ - mum is specified at two values of •c at a case temperature of 100°C, with tha-device driving a clamped inductive load. A blocking voltage rating, V£EV> * s specified at the same case tem- perature and maximum values for V CE (sat). V BE (sat). ICEV and ICER are a lso provided. Fall time and storage time, im- portant parameters for switching performance, are specified at rated Ic, VcEX (SUS) and Tj = 100°C, with an inductive load. CHARACTERISTICS OF NEW SWITCHMODE POWER TRANSISTORS *T C = +25°C, unless other- wise noted 2N6542 2N6543 2N6544 2N6545 2N6546 2N6547 V C EX @ T C = +100°C 350 V 450 V 350 V 450 V 350 V 450 V V CEV 650 V 850 V 650 V 850 V 650 V 850 V v CEO 300 V 400 V 300 V 400 V 300 V 400 V V CE (SAT) T c = 100°C 2 V 2 V 2.5 V 2.5 V 2.5 V 2.5 V V BE (SAT) @t c = +100°C 1.4 V 1.4 V 1.6 V 1.6 V 1.6 V 1.6 V Ic peak (Amps) 10 10 16 16 30 30 Iq continuous (Amps) 5 5 8 8 15 15 E s / b (min) joules 1 80 p\ 180 p\ 500 p\ 500 p\ 2mj 2m j Hp£ (min) 7 7 7 7 6 6 td (max) psec .05 .05 .05 .05 .05 .05 t r (max) psec 0.7 0.7 1.0 1.0 1.0 1.0 t s (max) psec 4/4* 4/4* 4/4* 4/4* 4/5* 4/5* tf (max) jusec 0.8/ 0.8/ 1.0/ 1.0/ 0.7/ 0.7/ 0.8* 0.8* 0.9* 0.9* 1.5* 1.5* Pq watts 100 100 125 125 175 175 *Tq = +100°C Inductive load operating conditions. New Mains Filters for Electrical Equipment Tekdata announce the availability in U.K. of a new mains filter incorporating an I.E.C. socket. The units are Underwriters Laboratories approved and are de- signed in accordance with the I.E.C. , V.D.E., C.S.A. and the proposed American Standards Association specifications. Each filter measures only 40.6 mm square by 20.5 mm high, and is incorporated in the panel-mounted recessed connec- tor on the equipment. Current ratings from 1 to 6 amps, are available, for voltages of 125/250 at 0 to 60 Hz. Equipment con- nection to the mains input/filter combination is by solder lugs. Maximum leakage to earth is 0.25 mA at 125 V, and 0.5 mA at 250 V ; the filters will withstand a dielectric test of 2,100 V d.c. Tekdata Ltd, Westport Lake, Canal Lane, Tunstall, Stoke on Trent, Staffs. ST6 4PA. Heat sinks The range of heat sinks produced by Dieter Assmann Electronics Limited now includes extruded metal, die cast, staggered finger and spring types. More than 35 different versions of standard extruded metal heat sinks are stocked. The total range of standard products, which in- cludes more than 80 heat sinks of a variety of shapes and dimen- sions, is one of the most compre- hensive available from a single source. Dieter Assmann Electronics Ltd, Victoria Works, Water Lane, Watford, Herts. WD1 2NW. 1156 — elektor november 1975 advertisemen [ In connection with the rapid growth of Elektor, we are now looking for an assistant The successful applicant will have the opportunity to assist in the technical development of our magazine. Conditions of employ- ment: attractive salary, 37% hour week, 8.3% holiday bonus and 3.5% Christmas bonus, etc. Applications with career details should be addressed to the Managing Director, Elektor Publishers Ltd, 6 Stour Street, Canterbury CT1 2XZ. Applicants should have a sound knowledge of electronics and an ability to write lucidly on that sub- ject. Previous journalistic experi- ence is not essential but would be an advantage, as would a knowledge of the German language. [ HARDWARE A comprehensive range of screws, nuts, washers etc. in small quan- tities, and many useful constructors' items. Sheet aluminium to individual requirements, punched, drilled, etc. Fascia panels, dials, nameplates in etched aluminium. Printed circuit boards to personal designs, one-off's or small runs. Machine engraving in metals and plastics, contour milling. Send lOp stamps for catalogue. RAMAR Constructor Services Masons road Stratford on Avon Warwicks. CV37 9NF. Missing link The most recent experiments with the TAP- power (this issue, page 1 130) have shown that the most reliable circuit for the touch inputs is as follows: — capacitors Ca and Cd are included across the touch contacts, Cb and Cc are omitted; — the connections from the touch panels to the main pcb are made via 1 Mf2 series resistors instead of wire links, e.g. a 1 MS2 resistor connects the junction of the 'ON' touch panel and Ca to the junction of R20 and pin 8 of N1 . PLASTIC BOXES Two new ranges of ABS plastic boxes are offered at competitive prices and with short deliveries. The first range, for electronic circuits and controls, gives volumes from 348 to 1 ,369 cc in four sizes. The second, for potting, gives 41 to 187 cc in three sizes. ABS material is said to be antistatic, easily punched and drilled, and capable of withstanding 100°C. Standard colours offered are grey, blue, orange and red. Albol Ltd. 3 Crown Buildings, Crown Street, London SE5. market elektor november 1975 — 1157 Mercury-wetted relays From Astralux Dynamics Limited, the 270/280 series of miniature mercury-wetted reed relays are ideal for low-level switching applications. The mercury wetting of the relay contacts eliminates electrical contact ‘bounce' and gives a stable contact resistance (initial contact rating 0.05 £2 maximum). The avoidance of spurious operation means that the devices are suitable for interfacing with low-level logic equipment, while the relatively high power ratings enable the relays to be used for switching inductive loads. The life expectancy is also increased : up to 50 x 10 6 operations. The relays are available in l Form A, 2 Form A, 1 Form C md 2 Form C configurations. Ratings for the Form A types are: breakdown 1.2 kV d.c. minimum; .witching 200 V, 1 mA and 28 V, L A (1 kV d.c. and 2 A d.c. maxi- mum); d.c. contact rating 50 VV naximum. The corresponding Igures for the Form C types are: breakdown 1 kV d.c. minimum; witching 200 V, 1 mA and 28 V, l A (200 V d.c. and 1 A d.c. naximum); d.c. contact rating 14 W maximum. Astralux Dynamics Limited, Srightlingsea, Colchester, Essex, CO 7 OSW. P.C.B. Transfer System This system, from J.H. Equipment Ltd allows the production of high-quality one- off printed circuits without re- course to photography. The etch- resistant pads and tracks are laid out on the copper side of the board and the resulting circuit can then be etched. The manufac- turers claim that their method of applying the adhesive to the sym- bols gives better definition than similar systems, as there is no ad- hesive overlap which can produce ragged edges. The system is available in kits of ten sheets of symbols as illus- trated. Metallised plastic film capacitors Designated Type MKM, these capacitors are the latest in a series developed by Siemens and feature exceptional compactness, stab- ility, low loss and close tolerance. They have been introduced principally for use in completely automated production systems but, in a protected version, are also well suited to applications in both professional and semi- professional electronic equip- ment. Individual capacitors are cut from a large ‘mother’ capacitor of known value, on which many of the processes necessary to the production of discrete units have already been carried out. In this way a uniformity of the electrical characteristics of the capacitors is achieved, which is not possible when produced individually. Currently, LST Electronic Com- ponents stock the B32551 version of the MKM capacitor. This is available at voltage ratings of 100 V d.c. and preferred values of 10 to 68 nF, and at 250 V d.c. and preferred values of 100, 150 and 220 nF. The pin spacing of the B32551 is 10 mm. LST Electronic Component Ltd, Victoria Road, Chelmsford, Essex. Inexpensive Programmable Op-Amp A single external resistor allows the characteristics of a new Motorola op-amp to be optimised to suit power supplies from ±6 to ±15 V. Parameters which are programmed by the external resistor include input current and voltage, power con- sumption and current noise. The new op-amp, designated type MC3476, does not require fre- quency compensation, has offset null capability and is fully pro- tected against damage from short circuits. A typical power con- sumption of only 4.8 mW makes the MC3476 a good choice for use in battery powered equipment. The data sheet gives the typical offset voltage, offset current and bias current as 2 mV, 2 nA and 15 nA respectively. Input resistance and capacitance are 5 M£2 and 2 pF, while input common-mode voltage range, common-mode rejection ratio and supply voltage rejection ratios are quoted as ±10 V, 70 dB and 25 jltV/V respectively. The output resistance is 1 k£2 and the output current into a short circuit is typically 12 mA. From the performance point of view the MC3476 offers a mini- mum large signal voltage gain of 50 kV/V (min) with a 10 k£2 load and an output voltage swing of ±10 V at 25°C. Slew rate with the same load is 0.8 V//Ltsec and the unity gain transient response is typically 0.35 /isec. Motorola Ltd, Semiconductor Products Division, York House Empire Way, Wembley, Middlesex. MOTOROLA INC. 'Semiconductor Products Division Technical Rrmma Information MC3476 PROGRAMMABLE OPERATIONAL AMPLIFIER CASE 601 03 FI SUFFIX PLASTIC FACKAGl CASf 676 OllHI Null lA.prftu., Input Np. I.rtit.| Input V|» INPUT BIAS CURRENT ..nut SET CURRENT GAIN BANDlftlOTH FROOUCT ICBFVI ....up SE T CURRENT •• It Sf* Cu»«IM i«AI OPEN LOOP CAIN ...put SET CURRENT R„, la NEGATIVE SUPPLY ' 0 »« Ti itt W CC v 1 f • 10. A ' Ml * V CC v ti •„,* I0.A •mi * ’»•* •ft 0 V MO >1) 360 fc (1 •eov 1 0 Mfl bjo ft n l»OV B?0 .1! 360 ft (1 ♦» 0 V ft B ME) 1 2 MEl I t 12 V 1 O MU 750 *11 ♦ 12 V I 2 MU 1 S MU t 1ft V 1 » MU 1 0 M(1 115 V 2 7 Mil TO MU 1158 — elektor november 1975 advertisemen SEMICONDUCTORS Ei TRANSISTORS BRAND NEW FULLY GUARANTEED Type AC107 AC113 AC115 AC117K AC122 AC 125 AC 126 AC127 AC128 AC 132 AC134 AC137 AC141 AC141K AC142 AC142K AC151 AC154 AC155 AC156 AC157 AC165 AC166 AC167 AC 168 AC 169 AC 176 AC177 AC 178 AC179 AC 180 AC180K AC181 AC181K AC187 AC187K AC 188 AC188K ACY17 ACY18 ACY19 ACY20 ACY21 ACY22 ACY27 ACY28 ACY29 ACY30 ACY31 ACY34 BC173 BC174 BC175 BC177 BC178 BC179 BC180 BC181 BC182 BC182L BC183 BC183L BC184 BC184L BC186 BC187 BC207 BC208 BC209 BC212L BC213L BC214L BC225 BC226 BC301 BC302 BC303 BC304 BC440 BC460 BCY30 BCY31 BCY32 BCY33 BCY34 BCY70 BCY71 BCY72 BCZ10 BCZ11 BCZ12 BD115 BD116 BD121 BD123 BD124 BD131 BD132 BD133 BD135 BFY53 BSX19 BSX20 BSY25 BSY26 BSY27 BSY28 BSY29 BSY38 BSY39 Price 0.20 0.19 0.20 0.30 0.12 0.18 0.18 0.19 0.19 0.15 0.15 0.15 0.19 0.30 0.19 0.26 0.16 0.20 0.20 0.20 0.25 0.20 0.20 0.20 0.25 0.15 0.20 0.25 0.29 0.29 0.20 0.30 0.20 0.30 0.22 0.23 0.22 0.23 0.26 0.20 0.20 0.20 0.20 0.17 0.19 0.19 0.36 0.29 0.29 0.21 0.15 0.15 0.22 0.19 0.19 0.19 0.25 0.25 0.15 0.15 0.15 0.15 0.20 0.20 0.29 0.29 0.11 0.11 0.12 0.18 0.13 0.17 0.26 0.36 0.28 0.25 0.31 0.37 0.31 0.37 0.25 0.27 0.31 0.22 0.26 0.15 0.20 0.15 0.20 0.26 0.26 0.63 0.81 0.61 0.67 0.70 0.51 0.61 0.67 0.41 0.18 0.16 0.16 0.16 0.16 0.16 0.16 0.16 0.19 0.19 Type BSY40 BSY41 BSY95 BSY95A BU105 Cl 1 1E C400 C407 C424 C425 C426 C428 C441 C442 C444 C450 MAT 100 MAT101 MAT 120 MAT121 MJE521 MJE2955 MJE3055 MJE3440 MPF102 MPF104 MPF105 OC19 OC20 OC22 OC23 OC24 OC25 OC26 OC28 OC29 OC35 OC36 OC41 OC42 2N918 2N929 2N930 2N1131 2N1132 2N1302 2N1303 2N1304 2N1305 2N1306 2N1307 2N1308 2N1309 2N1613 2N1711 2N1889 2N1890 2N1893 2N2147 2N2148 2N2192 2N2193 2N2194 2N221 7 2N2218 2N2219 2N2220 2N2221 2N2222 2N2368 2N2369 2N2369A 2N2411 2N2412 2N2646 2N2711 2N2712 2N2714 2N2904 2N2904A 2N2905 2N2905A 2N2906 2N2906A 2N2907 2N2907A 2N2923 2N2924 2N2925 ACY35 ACY36 ACY40 ACY41 ACY44 AD 130 AD140 AD142 AD143 AD149 AD161 AD162 AD161 & AD162(MP) 0.69 Price 0.29 0.29 0.13 0.13 £2.04 0.51 0.31 0.26 0.26 0.51 0.36 0.20 0.31 0.31 0.36 0.22 0.19 0.20 0.19 0.20 0.56 0.88 0.57 0.51 0.43 0.38 0.38 0.36 0.65 0.47 0.49 0.57 0.39 0.30 0.51 0.51 0.43 0.51 0.20 0.25 0.31 0.^1 0.21 0.20 0.22 0.15 0.15 0.18 0.18 0.21 0.21 0.24 0.24 0.20 0.20 0.32 0.46 0.38 0.73 0.58 0.36 0.36 0.36 0.22 0.20 0.20 0.22 0.20 0.20 0.18 0.15 0.15 0.25 0.25 0.48 0.21 0.21 0.21 0.18 0.21 0.21 0.21 0.16 0.19 0.20 0.22 0.15 0.15 0.15 0.21 0.29 0.18 0.19 0.36 0.39 0.49 0.49 0.39 0.51 0.36 0.36 ADT140 AF114 AF115 AF116 AF117 AF118 AF124 0.51 0.25 0.25 0.25 0.25 0.36 0.31 Type AF125 AF126 AF127 AF139 AF178 AF179 AF180 AF181 AF186 AF239 AL102 AL103 ASY26 ASY27 ASY28 ASY29 ASY50 ASY51 ASY52 ASY54 ASY55 ASY56 ASY57 ASY58 ASY73 ASZ21 BC107 BC108 BC109 BD136 BD137 BD138 BD139 BD140 BD155 BD175 BD176 BD177 BD178 BD179 BD180 BD185 BD186 BD187 BD188 BD189 BD190 BD195 BD196 BD197 BD198 BD199 BD200 BD205 BD206 BD207 BD208 BDY20 BF115 BF117 BF118 BF1 19 BF121 BF123 BF125 BF127 BF152 BF153 BF154 BF155 BF156 BF157 BF158 BF159 BF160 BF 162 BF163 BF164 BF165 OC44 OC45 OC70 OC71 OC72 OC74 OC75 OC76 OC77 OC81 OC81D OC82 OC82D OC83 OC139 OC140 OC169 OC170 OC171 OC299 OC201 OC202 OC203 OC204 OC205 OC309 OCP71 ORP12 ORP60 ORP61 P20 Price 0.31 0.29 0.29 0.31 0.51 0.51 0.51 0.51 0.51 0.38 0.68 0.68 0.26 0.31 0.26 0.26 0.26 0.26 0.26 0.26 0.26 0.26 0.26 0.26 0.26 0.41 0.08 0.08 0.08 0.41 0.46 0.51 0.56 0.61 0.81 0.61 0.61 0.67 0.67 0.71 0.71 0.67 0.67 0.71 0.71 0.77 0.77 0.87 0.87 0.92 0.92 0.98 0.98 0.81 0.81 0.98 0.98 £ 1.02 0.25 0.46 0.71 0.71 0.46 0.51 0.46 0.51 0.56 0.46 0.46 0.71 0.49 0.56 0.56 0.61 0.41 0.41 0.41 0.41 0.41 0.16 0.13 0.10 0.10 0.15 0.15 0.16 0.16 0.26 0.16 0.16 0.16 0.16 0.20 0.20 0.20 0.26 0.26 0.26 0.26 0.29 0.29 0.26 0.26 0.36 0.41 0.44* 0.44* 0.41* 0.41* 0.51* Type P346A P397 ST140 ST141 TIP29 TIP30 TIP31A TIP32A TIP41A TIP42A TIS43 UT46 ZN414 2G301 2G302 2G303 2G304 2G306 2G308 2N2926 2N2926 2N2926 2N2926 2N2926 B 2N3010 2N3011 2N3053 2N3054 2N3055 2N3319 2N3391 A 2N3392 2N3393 2N3394 2N3395 2N3402 2N3403 2N3404 2N3405 2N3414 2N3415 2N3416 2N3417 2N3525 2N3614 2N3615 2N3616 2N3646 2N3702 2N3703 2N3704 2N3705 2N3706 2N3707 2N3708 2N3709 2N3710 2N3711 2N3819 2N3820 2N3821 2N3823 2N3903 2N3904 2N3905 2N3906 2N4058 2N40591 2N4060 BC113 BC114 BC115 BC116 BC117 BC118 BC1 19 BC120 BC125 BC126 BC132 BC134 BC135 BC136 BC137 BC139 BC140 BC141 BC142 BC143 BC145 BC147 BC148 BC149 BC150 BC151 BC152 BC153 BC154 BC157 BC158 BC159 BC160 BC161 BC167 BC168 BC169 BC170 BC171 BC172 BF 167 Price 0.20 0.43 0.13 0.18 0.44 0.52 0.56 0.68 0.68 0.81 0.31* 0.28* 1.11 0.19 0.19 0.19 0.25 0.41 0.36 0.13 0.11 0.10 0.10 0.10 0.71 0.15 0.18 0.47 0.42 0.15 0.17 0.15 0.15 0.15 0.18 0.21 0.21 0.29 0.43 0.16 0.16 0.29 0.29 0.77* 0.69 0.76 0.76 0.09 0.12 0.12 0.13 0.12 0.12 0.13 0.08 0.09 0.09 0.09 0.29 0.51 0.36 0.29 0.29 0.31 0.29 0.28 0.12 0.10 0.12 0.10 0.16 0.16 0.16 0.19 0.10 0.81 0.81 0.12 0.19 0.12 0.19 0.12 0.16 0.16 0.41 0.31 0.31 0.31 0.31 0.46 0.10 0.10 0.12 0.19 0.20 0.18 0.29 0.31 0.19 0.12 0.12 0.46 0.51 0.12 0.12 0.12 0.12 0.15 0.15 0.22 Type BF 1 73 BF 1 76 BF 1 77 BF178 BF 1 79 BF 1 80 BF181 BF182 BF 183 BF184 BF 185 BF 187 BF 188 BF194 BF195 BF196 BF197 BF200 BF222 BF257 BF258 BF259 BF262 BF263 BF270 BF271 BF272 BF272 BF273 BF274 BFW20 BFX29 BFX84 BFX85 BFX86 BFX87 BFX88 BFY50 BFY51 BFY52 2G309 2G339 2G339A 2G344 2G345 2G371 2G371B 2G373 2N524 2N527 2N598 2N599 2N696 2N697 2N698 2N699 2N706 2N706A 2N708 2N711 2N717 2N718 2N718A 2N726 2N727 2N743 2N744 2N914 2N4061 2N4062 2N4284 2N4285 2N4286 2N4287 2N4288 2N4289 2N4290 2N4291 2N4292 2N4293 2N5172 2N5194 2N5294 2N5296 2N5457 2N5458 2N5459 2N6122 25301 2S302A 25302 25303 25304 25305 25306 25307 2S321 Price 0.22 0.36 0.36 0.31 0.31 0.31 0.31 0.41 0.41 0.26 0.31 0.28 0.41 0.12 0.12 0.15 0.15 0.46 0.98 0.46 0.61 0.87 0.56 0.56 0.36 0.31 0.81 0.81 0.36 0.36 0.61 0.28 0.22 0.31 0.22 0.25 0.22 0.20 0.20 0.20 0.37 0.20 0.17 0.19 0.17 0.17 0.12 0.18 0.43 0.50 0.43 0.46 0.13 0.14 0.25 0.36 0,08 0,09 0.12 0.31 0.36 0.25 0.51 0.29 0.29 0.20 0.20 0.15 0.12 0.12 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.12 0.56 0.56 0.56 0.32 0.32 0.41 0.69 0.51 0.43 0.43 0.56 0.71 0.80 0.80 0.80 0.75 74 SERIES T.T.L. I.C's BIPAK STILL LOWEST IN PRICE. FULL SPECIFICATION GUARANTEED. ALL FAMOUS MANUFACTURERS. Type Quantities 1 25 100+ Type Quantities 1 25 100+ Type Quantities 1 25 100+ 7400 0.14 0.18 0.12 7448 £1.02 0.99 0.97 74122 0.65 0.63 0.60 7401 0.14 0.13 0.12 7450 0.14 0.13 0.12 74123 0.69 0.68 0.65 7402 0.14 0.13 0.12 7451 0.14 0.13 0.12 74141 0.79 0.76 0.73 7403 0.14 0.13 0.12 7453 0.14 0.13 0.12 74145 £1.20 £1.16 £1.11 7404 0.14 0.13 0.12 7454 0.14 0.13 0.12 74150 £1.39 £1.30 £1 .20 7405 0.14 0.13 0.12 7460 0.14 0.13 0.12 74151 £1.02 0.97 0.93 7406 0.36 0.31 0.29 7470 0.30 0.27 0.25 74153 0.93 0.88 0.83 7407 0.36 0.31 0.29 7472 0.30 0.27 0.25 74154 £1.57 £1 48 £1.48 7408 0.28 0.22 0.21 7473 0.38 0.36 0.32 74155 £1.11 £1.06 £1.02 7409 0.23 0.22 0.21 7474 0.38 0.36 0.32 74156 £1.11 £1.06 £1.02 7410 0.14 0.13 0.12 7475 0.56 0.54 0.52 74157 0.93 0.88 0.83 7411 0.23 0.22 0.21 7476 0.41 0.40 0.39 74160 £1.30 £1.25 £1.20 7412 0.26 0.25 0.24 7480 0.56 0.54 0.51 74161 £1.30 £1.25 £1.25 7413 0.30 0.29 0.28 7481 £1.02 0.97 0.93 74162 £1.30 £1.25 £1.20 7416 0.28 0.27 0.26 7482 0.83 0.79 0.74 74163 £1.30 £1.25 £1.20 7417 0.28 0.27 0.26 7483 £1.11 £1.06 0.97 74164 £1.67 £1.62 £1.55 7420 0.14 0.13 0.12 7484 0.93 0.90 0.88 74165 £1.67 £1.62 £1.55 7422 0.28 0.27 0.26 7485 £1.48 £1.44 £1.39 74166 £1.48 £1.44 £1.39 7423 0.37 0.36 0.35 7486 0.32 0.31 0.30 74174 £1.48 £1.44 £1.39 7425 0.37 0.36 0.35 7489 £3.70 £3.47 £3.24 74715 £1.02 0.97 0.93 7426 0.37 0.35 0.33 7490 0.60 0.58 0.56 74176 £1.16 £1.11 £1.06 7427 0.37 0.35 0.33 7491 £1.02 0.97 0.93 74177 £1.16 £1.11 £1.06 7428 0.42 0.39 0.37 7492 0.69 0.66 0.59 74180 £1.16 £1.11 £1.06 7430 0.14 0.13 0.12 7493 0.69 0.66 0.59 74181 £3.66 £3.56 £3.47 7432 0.37 0.35 0.33 7494 0.79 0.76 0.69 74182 £1.16 £1.11 £1.06 7433 0.39 0.37 0.35 7495 0.79 0.76 0.69 74184 £1.67 £1.62 £1.55 7437 0.32 0.30 0.28 7496 0.89 0.86 0.80 74190 £1.81 £1.76 £1.71 7438 0.32 0.30 0.28 74100 £1.39 £1.34 £1.30 74191 £1.81 £1.76 £1.71 7440 0.14 0.13 0.12 74104 0.56 0.54 0.51 74192 £1.81 £1.76 £1.71 7441 0.69 0.66 0.59 74105 0.56 0.54 0.51 74193 £1.81 £1.76 £1.71 7442 0.69 0.66 0.59 74107 0.41 0.39 0.37 74194 £1.20 £1.16 £1.11 7443 £1.11 £1.06 £1.02 74110 0.56 0.51 0.46 74195 £1.02 0.97 0.93 7444 £1.11 £1.06 £1.02 74111 0.83 0.81 0.78 74196 £1.11 £1.06 £1.02 7445 £1.48 £1.44 £1.39 74118 0.93 0.88 0.83 74197 £1.11 £1.06 £1.02 7446 £1.11 £1.06 £1.02 74119 £1.39 £1.30 £1.20 74198 £2.55 £2.50 £2.45 7447 £1.02 0.99 0.97 74121 0.46 0.44 0.41 74199 £2.31 £2.21 £2.11 Devices may be mixed to qualify for quantity prices, the above series of I.C's in booklet form. PRICE 35p. (TTL 74 series only) data is available for LINEAR I.C's 2G374 0.18 Type Quantities Type Quantities Type Quantities 2G377 0.31 1 25 100+ 1 25 100+ 1 25 100+ 2G378 0.17 72702 0.46 0.44 0.42 SL701C 0.46 0.42 0.37 /XA723C 0.45 0.43 0.40 2G381 0.17 72709 0.23 0.21 0.19 SL702C 0.46 0.42 0.37 76003 £1.39 £1.34 £1.30 2G382 0.17 72709P 0.19 0.18 0.17 TAA263 0.74 0.65 0.56 76023 £1.39 £1.34 £1.30 2G401 0.31 72710 0.32 0.31 0.28 TAA293 0.93 0.88 0.83 76660 0.88 0.86 0.83 2G414 0.31 72741 0.28 0.27 0.26 TAA350A £1.71 £1.67 £1.57 LM380 0.93 0.90 0.88 2G417 0.26 72741C 0.26 0.25 0.24 /JA703C 0.26 0.24 0.22 NE555 0.45 0.43 0.40 2N388 0.36 72741 P 0.28 0.27 0.26 JLA709C 0.19 0.18 0.17 NE556 0.88 0.86 0.83 2N388A 0.56 72747 0.79 0.74 0.61 /UA711C 0.32 0.31 0.28 TBA800 £1.39 £1.34 £1.30 2N404 0.20 72748P 0.35 0.33 0.31 H A712C 0.32 0.31 0.28 ZN414 £1.11 — — 2N404A 0.29 SL201C 0.46 0.42 0.37 TRIACS Case 100 V 200V 400V 2 Amp T05 0.31 0.51 0.71 6 Amp TO66 0.51 0.61 0.77 10 Amp TQ48 0.77 0.92 £1.12 ALL PRICES PLEASE ADD VA ITEMS EXCEPT 11 D.I.L. SOCKETS 1 25 100+ TS014 14 pm type .0.31 0.28 0.25 TS016 16 pin type .0.35 0.32 0.30 TS024 24 pin type .0.69 0.64 0.62 BPS 8 8 pin type (low cost) . . .0.14 0.12 0.10 BPS14 14 pin type (low cost) . . .0.15 0.13 0.11 BPS16 16 pin type (low cost) . . .0.16 0.14 0.12 GIRO NUMBER 388-7006 Postage & Packing Add extra for airmail D.T.L. 930 SERIES Type Quantities Type Quantities Type Quantities 1 25 100+ 1 25 100+ 1 25 100+ BP930 0.14 0.13 0.12 BP944 0.15 0.14 0.13 BP962 0.14 0.13 0.12 BP932 0.15 0.14 0.13 BP945 0.28 0.26 0.23 BP9093 0.42 0.40 0.38 BP933 0.15 0.14 0.13 BP946 0.14 0.13 0.12 BP9094 0.42 0.40 0.38 BP935 0.15 0.14 0.13 BP948 0.28 0.26 0.23 BP9097 0.42 0.40 0.38 BP936 0.15 0.14 0.13 BP951 0.65 0.60 0.56 BP9099 0.42 0.40 0.38 SILICON RECTIFIERS 300mA 750mA 1 Amp 1*5 Amp 3 Amp 10 Amp 30 Amp PIV (DO 7) (SO 16) Plastic (SO 16) (SO 10) (SO 10) (TO 48) 50 0.05 0.06 1N4001 0.05 0.07 0.14 0.19* 0.56* 100 0.05 0.07 1N4002 0.06 0.09 0.16 0.21* 0.69* 200 0.06 0.09 1 N4003 0.07 0.12 0.20 0.23* 0.93* 400 0.07 0.14 1N4004 0.08 0.14 0.28 0.35* £1.25* 600 0.08 0.16 1N4005 0.09 0.16 0.33 0.42* £1.76* 800 0.11 0.18 1N4006 0.10 0.18 0.35 0.51* £1.94* 1000 0.13 0.28 1N4007 0.11 0.23 0.44 0.60* £2.31* 1200 — 0.32 0.28 0.54 0.69* £2.88* advertisement elektor november 1975 — 1159 PO BOX 6 WARE HERTS SUPER UNTESTED PAKS QUALITY TESTED PAKS MAMMOTH I.C. PAK Pak No. Description . Price £p U 1 120 Glass Sub-min. General purpose Germ, diodes 0.60 U 2 50 Mixed Germanium transistors AF/RF 0.60 U 3 75 Germanium gold bonded sub-min. like OA5, PA47 . . . 0.60 U 4 30 Germanium Transistors like OC81, AC1 28 0.60 U 5 60 200mA sub-min. silicon diodes 0.60 U 6 30 Sil. Planar trans. NPN like BSY95A, 2N706 0.60 U 7 16 Sil. rect. TOP-HAT 750mA, VLTG. RANGE up to 100 0.60 U 8 50 Sil. planar diodes DO-7 glass 250mA like OA200/202 . 0.60 U 9 20 Mixed voltages, 1 Watt Zener Diodes 0.60 U10 20 BAY50 charge storage diodes DO-7 glass 0.60 U11 20 PNP Sil. planar trans. TO-5 like 2N1 132, 2N2904. .. . 0.60 U13 30 PNP-NPN Sil. transistors OC200 & 2S1 04 0.60 U14 150 Mixed silicon and germanium diodes 0.60 U15 20 NPN Sil. planar trans. TO-5 like 2N696, 2N697 0.60 U16 10 3 Amp sil. rectifiers stud type up to 1000 PIV 0.60 U17 30 Germanium PNP AF transistors TO-5 like ACY 1 7-22 . 0.60 U18 8 6Amp sil. rectifiers BYZ13 type up to 600 PIV 0.60 U19 20 Silicon NPN transistors like BC 108 0.60 U20 12 1-5 Amp sil. rectifiers top hat up to 1000 PIV 0.60 U21 30 AF. Germ, alloy transistors 2G300 series & OC71 . . . . 0.60 U23 25 MADT's like MHz series PNP transistors 0.60 U24 20 Germ. 1 Amp rectifiers GJM series up to 300 PI V. . . . 0.60 U25 25 300 MHz NPN silicon transistors 2N708, BSY27 .... 0.60 U26 30 Fast switching silicon diodes like 1N914 Micro-Min. . . 0.60 U29 10 1 Amp SCR's TO-5 can. up to 600 PIV CRS1/25-600 . £1.20* U32 25 Zener diodes 400 mW DO-7 case 3-33 volts mixed ... 0.60 U33 15 Plastic case 1 Amp sil. rec'.ifiers 1N4000 series 0.60 U34 30 Silicon PNP alloy trans. TO-5 BCY26 2S302/4 0.60 U35 25 Silicon planar transistors PNP TO-18 2N2906 0.60 U36 20 Silicon planar NPN transistors TO-5 BFY50/51/52 . . . 0.60 U37 30 Silicon alloy transistors SO-2 PNP OC200, S2322 . . . . 0.60 U38 20 Fast switching silicon trans. NPN 400 MHz 2N301 1 . . 0.60 U39 30 RF. Ger. PNP transistors 2N 1303/5 TO-5 0.60 U40 10 Dual transistors 6 lead TO-5 2N2060 0.60 U43 25 Silicon trans. plastic TO-18 A. F. BC1 13/1 14 0.60 U44 20 Silicon trans. plastic TO-5 BC1 15 0.60 U45 7 3A SCR. TO-66 up to 600 PIV £1 .20* U46 20 Unijunction transistors similar to TIS43 0.60* U47 10T0220 AB plastic triacs 50 V 6 A £1.20* U48 9 NPN Sil. power transistors like 2N3055 £1.20 U49 12 NPN Sil. plastic power trans. 60 W like 2N5294/5296 . £1.20 Code No's mentioned above are given as a guide, to the type of device in the pak. The devices themselves are normally unmarked. EXCLUDE VAT VOLTAGE REGULATORS AT 25% TO ALL *ADD 87 , NO VAT add 20p overseas Minimum order 75p TO.3 Plastic Encapsulation JUA. 7805/Ll 29 5V (Equiv. to MVR5V) £1.25p /LIA.7812/L130 12V (Equiv. to MVR12V) £1.25p /JA.7815/L131 15V (Equiv. to MVR15V) £1.25p jiA.7818 18V (Equiv. to MVR18V) £1.25p r i PIV 0.6A 0.8A 1 A 3A 5A 5A 7A 1 0A 16A 30A T018 T092 T05 T066 T066 T064 T048 T048 T048 T048 10 0.13 0.15 — — — — — — — — 20 0.15 0.18 — — — — — — — — 30 0.19 0.22 — — — — — — — — 50 0.22 0.28 0.20 0.25 0.36 0.36 0.48 0.51 0.54 £1.18 100 0.25 0.30 0.25 0.25 0.48 0.48 0.51 0.57 0.58 £1.43 150 0.31 0.38 — — — — — — — — 200 0.38 0.44 0.25 0.30 0.50 0.50 0.57 0.62 0.62 £1.63 400 — — 0.30 0.39 0.55 0.57 0.62 0.71 0.77 £1.79 600 — — 0.39 0.48 0.69 0.69 0.78 0.99 0.90 — 800 — — 0.58 0.65 0.81 0.81 0.92 £1.22 £1.39 £4.07 Type Price Type Price Type Price Type Price AA119 0.08 BY101 0.12 BYZ16 0.41 OA85 0.09 AA120 0.08 BY105 0.18 BYZ17 0.36 OA90 0.07 AA129 0.08 BY 114 0.12 BYZ18 0.36 OA91 0.07 AAY30 0.09 BY 124 0.12 BYZ19 0.28 OA95 0.07 AAZ13 0.10 BY126 0.15 CG62 OA200 0.07 BA100 0.10 BY127 0.16 (OA91 Eq) 0.06 OA202 0.07 BA116 0.21 BY128 0.16 CG651 (OA70- SD10 0.06 BA126 0.22 BY 130 0.17 OA79) 0.07 SD1 9 0.06 BA148 0.15 BY 133 0.21 OA5 Short 1 N34 0.07 BA 154 0.12 BY 164 0.51 Leads 0.21 1N34A 0.07 BA155 0.15 BYX38/30 0.43 OA10 0.14 1N914 0.06 BA 156 0.14 BYZ10 036 OA47 0.07 1N916 0.06 BA173 0.15 BYZ11 031 OA70 0.07 1N4148 0.06 BB104 0.15 BYZ12 031 OA79 0.07 1S021 0.10 BY 100 0.16 BYZ13 0.26 OA81 0.07 1S951 0.70 Pak No. Quality Tested Paks Price Q 1 20 Red spot transistors PNP 0.60 Q 2 16 White spot R.F. transistors PNP . . . 0.60 Q 3 4 OC 77 type transistors 0,60 Q 4 6 Matched transistors OC44/45/81/ 81 D 0.60 Q 5 4 OC 75 transistors 0.60 Q 6 5 OC 72 transistors 0.60 Q 7 4 AC 128 transistors PNP high gain . . 0.60 Q 8 4 AC 126 transistors PNP 0.60 Q 9 7 0C81 type transistors 0.60 Q10 7 OC 71 type transistors 0.60 Q11 2 AC 127/128 Complementary pairs PNP/NPN 0.60 Q12 3 AF 1 16 type transistors 0.60 Q13 3 AF 1 17 type transistors 0.60 Q14 3 0C171 H.F. type transistors .... 0.60 Q15 7 2N2926 Sil. Epoxy transistors mixed colours 0.60 Q17 5 NPN 2 x ST. 141. & 3 x ST. 140 . . . 0.60 Q18 4 MADT'S 2 x MAT 100 & 2 x MAT 120 0.60 Q19 3 MADT'S 2 x MAT 101 & lx MAT 121 0.60 Q20 4 OC 44 Germanium transistors A.F. . 0.60 Q21 4 AC 127 NPN Germanium transistors 0.60 Q22 20 NKT transistors A.F. R.F. coded . . 0.60 Q23 10 OA 202 Silicon diodes sub-min . . . 0.60 Q24 8 OA 81 diodes 0.60 Q25 15 1N914 Silicon diodes 75 PIV 75 mA 0.60 Q26 8 OA 95 Germanium diodes sub- min-1N69 0.60 Q27 2 10A 60OPIV Silicon rectifiers 1S425B 0.60* Q28 2 Silicon power rectifiers BYZ 13. . . 0.60 Q29 4 Sil. transistors 2 x 2N696, 1 x 2N697, 1 x 2N698 0.60 Q30 7 Silicon switch transistors 2N706 NPN 0.60 Q31 6 Silicon switch transistors 2N708 NPN . . . . : 0.60 Q32 3 PNP Sil. trans. 2 x 2N1 131. 1 x 2N1 132 0.60 Q33 3 Silicon. NPN transistors 2N1 71 1 . . 0.60 Q34 7 Sil. NPN trans. 2N2369, 500 MHz (code P397) 0.60 Q35 3 Silicon. PNP TO-5 2 x 2N2904 & 1 x 2N2095 0.60 Q36 7 2N3646 TO-1 8 plastic 300 MHz NPN 0.60 Q37 3 2N3053 NPN Silicon transistors. . . 0.60 Q38 5 PNP transistors 3 x 2N3703, 2 x 2N3702 0.60 Q39 5 NPN transistors 3 x 2N3704, 2 x 2N3705 0.60 Q40 5 NPN transistors 3 x 2N3707, 2 x 2N3708 0.60 Q4 1 3 Plastic NPN TOI 8 2N 3904 0.60 Q43 5 BC 107 NPN transistors 0.60 Q44 5 NPN transistors 3 x BC 108, 2 x BC 109 0.60 Q45 3 BC 1 13 NPN TO-18 transistors . . . 0.60 Q46 3 BC 115 NPN TO-5 transistors .... 0.60 Q47 4 NPN high gain transistors 2 x BC 157, 2 x BC 168 0.60 Q48 3 BCY 70 PNP transistors TO-18 .. . 0.60 Q49 3 NPN transistors 2 x BFY 51 , 1 x BFY 52 0.60 Q50 7 BSY 28 NPN switch transistors TO-18 0.60 Q51 7 BSY 95A NPN transistors 300 MHz 0.60 Q52 8 BY 100 type silicon rectifiers .... £1.20 Q53 25 Sil. & Germ, trans. mixed all marked new £1.50 Q54 6 TIL 209 Red LED £1.20* Manufacturers ''Fall Outs’* which include Functional and part Functional Units. These are classed as 'out-of- spec' from the makers' very rigid specifications, but are ideal for learning about I.C's and experimental work. Pak No UIC00 UIC01 UIC02 UIC03 UIC04 UIC05 UIC06 UIC07 UIC10 UIC13 UIC20 UIC30 UIC40 UIC41 UIC42 UIC43 UIC44 UIC45 UIC46 UIC47 UIC48 UIC50 UIC51 UIC53 UIC54 UIC60 UIC70 Contents 12 x 7400 12 x 12 x 12 x 12 x 7401 7402 7403 7404 12 x 7405 8 x 7406 8 x 7407 12 x 7410 8 x 7413 12 x 7420 1 2 x 7430 1 2 x 7440 5 x 744 1 5 x 7442 5 x 7443 5 x 7444 5 x 7445 5 x 7446 7447 7448 7450 7451 5 x 5 x 12 x 12 x 12 x 7453 12 x 7454 12 x 7460 8 x 7470 Price 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 Pak No. UIC72 UIC73 UIC74 UIC75 UIC76 UIC80 UIC81 UIC82 UIC83 UIC86 UIC90 UIC91 - UIC92 = UIC93 - UIC94 =• UIC95 - UIC96 - UIC100 UIC121 -ox UIC141 - 5 x UIC151 - 5 x UIC154 - 5 x UIC193 = 5 x UIC199 = 5 x UIC XI 25 Assor- ted 74's Contents 8 x 7472 7473 7474 7475 7476 7480 7481 7482 7483 7486 7490 7491 7492 7493 7494 7495 7496 x 8 8 8 8 5 5 5 5 5 5 5 5 5 5 5 5 x x X X X X X X X X X X X X X X 5 - 5 - 5 5 5 5 5 Price 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 74100 0.60 74121 0.60 74141 0.60 74151 0.60 74154 0.60 74193 0.60 74199 0.60 £1.50 APPROX. 200 PIECES Assorted fall-out integrated circuits, including: Logic, 74 series, Linear, Audio and D.T.L. Many coded devices but some unmarked — you to identify. OUR SPECIAL PRICE £1.20p JUMBO SEMICONDUCTOR PAK Transistors— Germ, and Silicon. Rectifiers— Diodes— Triacs— Thyristors— I.C.'s and Zeners. ALL NEW AND CODED APPROX 100 PIECES Offering the amateur a fantastic bargain PAK and an enormous saving— identification and data sheet in every pak. ONLY £1.85p UNTESTED LIN PAKS Manufacturers "Fall Outs” which include Functional and part Functional Units. These are classed as 'out-of- spec' from the makers' very rigid specifications, but are ideal for learning about I.C.’s and experimental work. Pak No. Contents Price ULIC709 = 10 x 709 0.60 ULIC710 = 7x710 0.60 ULIC741 = 7x741 0.60 ULIC747 ■ 5x747 0.60 ULIC748 = 7x 748 0.60 Containing 75 of the C280 range of capacitors as- sorted in values ranging from .01 ^iF to 2.2 /jF. Complete with identification chart. FANTASTIC VALUE ONLY £1.20p. SIL. G.P. DIODES 300 mW 40 PIV (min) SUB-MIN FULLY TESTED Ideal for Organ builders 30 for 50p, 100 for £1.50, 500 for £5, 1000 for £9. G.P. SWITCHING TRANS TOI 8 SIM. TO 2N706/8 BSY27/28/95A All usuable devices. No open and shorts. ALSO AVAILABLE IN PNP similar to 2N2906, BCY 70 20 for 50p, 50 for £1, 100 for £1.80. 500 for £8, 1000 for £14. When ordering please state NPN or PNP G.P. 100 30 WATT GERMANIUM T03 METAL CASE Vcbo 80 V. Vceo 50 V, 1C 10 A, Hfe 30-170 replaces the majority of Germanium power Transistors in the OC AD NKT range. 1-24 25-99 100+ 44 p 41p 37p 115 WATT SILICON T03 METAL CASE Vcbo 100 V, Vceo 60 V, 1C 15 A. Hfe, 20-100 suit- able replacement for 2N3055, BDY11 or BDY20 1-24 25-99 . 100+ 50p 48p 46 p INDICATORS 3015F Minitron 7 Segment Indicator £1.11p* MAN 3M L.E.D. 7 SEGMENT DISPLAY 0.127" High Characters £1.76p* ZENER DIODES 400 mW 8p FULL RANGE IN STOCK VOLTAGE RANGE 2-33 V 1.5 W 17p 10W* 30p 1160 — elektor november 1975 advertisemeni H.M. ELECTRONICS SHEFFIELD S103BD 275a, Fulwood Road, Broomhill, Tel: 0742-669676 BEC CABINETS (Book End Chassis) Standard cabinet GB1 14"x6"x2" GB1 A9"x6"x2" GB2 14"x7”x3" GB3 14"x9"x4" GB4 14"x9"x6” Send 15p for wallet of leaflets (Refundable on 1st purchase) A beautifully designed modern cabinet with simulated black leatherette top (PVC bonded to metal) solid wooden end cheeks, with room at the back for Output Sockets etc. Felt pads are fitted on bottom of cheeks for non-scratch. The Castle 8.RS.DD. A highly sensitive, full range eight inch unit designed for use in the recommended cabinet, or one of similar dimension. Suitable for use with good quality stereo installations, tape recorders, car radios, public address and background music systems, it has a frequency range of 50 to 20,000kHz - the lower limit variable with increases in cabinet volume. Recommended retail price is £9.00 excluding VAT. Aluminium Voice Coil High Flux 14,000 Oersteds Ceramic Magnet Roll Surround Double Diaphragm 8" Die -cast Chassis 8 ohms Impedance 15 Watt DIN Power Handling Acoustics Limited Park Mill, Shortbank Road, Skipton, Yorks. Tel: Skipton 5333. advertisement elektor november 1975 — 1161 ■mum M aUADRAPiHONY LICENSEES FOR CBS SQ, JVC CD4 and SANSUI QS QUADRAPHONIC SYSTEMS Complete kits of parts and P.C.B. to licenser’s specification CBS SQ MATRIX DECODER TYPE Ml. . . KIT £ 8.00 BUI LT £ 9.00 CBS SQ FULL LOGIC TYPE LI A KIT £21.00 BUI LT £23.00* CBS SQ FULL LOGIC TYPE L2A KIT £25.50 BUI LT £27.50 CBS SQ FULL LOGIC TYPE L3A KIT £29.50 BUI LT £32.50 CBS SQ STEREO TO QUAD SYNTHESISOR . KIT £14.00 BUI LT £15.50 CD4 DEMODULATOR £20.00 BUI LT £22.00* QS VARIOMATRIX DECODER. . . £18.00 BUI LT £20.00* * As described in Elektor June 1975 "Quadro in Practice" Circuits 2, 4 an 6 on Pages 647, 649 and 650. ALL KITS INCLUDE FINEST TOLERANCE COMPONENTS, FIBRE GLASS P.C.B. 's AND ALL IC's LICENSE FEE PAID New range of ELEKTOR project Equa Amplifier Kit £ 9.00 Mos Clock 5314 Kit £ 18.00 Mos Clock Timebase Kit £ 10.00 Disc Pre-Amp 76131 Kit £ 4.00 TV-Sound Kit £ 9.90 Tap Pre-Amp Kit £ 11.00 P.C.B.’s £ 7.00 £ 2.75 £ 5.00 ALL PCB's & PARTS SOLD SEPARATELY MINIMUM ORDER £ 1.00 plus 25% VAT kits complete with ELEKTOR CA 3090 AQ Stereo Decoder Kit Electronic Loudspeaker Kit (2-Way) . Loudspeaker Kit (3-Way) . SOLE MANUFACTURERS OF THE COMPLETE RANGE OF THE RONDO QUADRAPHONIC SYSTEM AS DESCRIBED IN "PRACTICAL ELECTRONICS", SEPTEMBER 1973 TO JULY 1974. SUPERVISED AND APPROVED BY THE AUTHOR, R.A. COLE. MAIL ORDER SUPERVISOR SHELAGH LONGMAN ’LEASE SUPPLY: KIT BUILT KIT CBS SQ MATRIX DECODER TYPE Ml EQUA AMPLIFIER KIT CBS SQ FULL LOGIC TYPE LI A MOS CLOCK 5314 KIT CBS SQ FULL LOGIC TYPE L2A MOS CLOCK TIMEBASE KIT CBS SQ FULL LOGIC TYPE L3A DISC PRE-AMP 76131 KIT CBS SQ STEREO TO QUAD SYNTHESISOR TV SOUND KIT CD4 DEMODULATOR TAP PRE-AMP KIT QS VARIOMATRIX • RONDO DETAILS CA 3090 AQ STEREO DECODER ELECTRONIC LOUDSPEAKER 2 3 x NAME ADDRESS TOTAL ENCLOSED £ CASH ALL PRICES INCLUDE POSTAGE & PACKING. PLEASE ADD 25% VAT TO ALL PRICES EXCEPT MOS CLOCK (8%). 10-14, BURWELL ROAD, LEYTON, LONDON, E.10. TELEPHONE 01-539 0347 1162 — elektor november 1975 advertisement babani press You can now obtain these best-selling reference works through Elektor at Canterbury: Please send me (tick circle) O O o o o First book of transistor] (equivalents and substitutes 40 p Second book of transistor equivalents and substitutes 95 p Handbook of integrated circuits, equiv- alents and substitutes 75 p Practical electronic science projects . . 75 p Practical stereo and quadro- phony handbook . . . 75 p I enclose remittance of for the books and 20 p post and packing. Name Address Postcode The new Rank WOW& FLUTTER _ leter Type 1 4 Fully transistorised for high reliability Versatile Meets in every respect all current specifications for measurement of Wow, Flutter and Drift on Optical and Magnetic sound recording/reproduction equipment using film, tape or disc High accuracy with crystal controlled oscillator Simple to use accepts wide range of input signals with no manual tuning or adjustment Two models available: Type 1742 'A' BS 4847: 1972 DIN 45507 CClR 409-2 Specifications Type 1742 'B' BS 1988: 1953 Rank Kalee Specifications For further information please address your enquiry to Mrs B.Nodwell Rank Film Equipment, PO Box 70 Great West Road, Brentford Middlesex TW8 9HR Tel: 01-568 9222* Telex 24408* Cables Rankaudio Brentford RANK FILM EQUIPMENT EK-ll FOR FURTHER DETAILS E5 advertisement elektor november 1975 — 1163 Look through this issue of ELEKTOR and you will find that ELEKTOR is not just one more electronics magazine. ELEKTOR is different different — in its presentation — in its style and content — in its use of new techniques and components in practical circuits. ELEKTOR is the magazine for your profession, study or hobby. ELEKTOR avoids long-winded theoretical discussions and the like. Instead, it gives practical applications. If you order a subscription, you will be sure to receive ELEKTOR regularly*. Fill in the form overleaf and send it today to ELEKTOR PUBLISHERS LTD. * ELEKTOR is also on sale at leading component shops, newsagents and stationers throughout the UK. eekfor binders The dark green binder collects your loose copies of ELEKTOR into one handy volume. Each copy is fastened simply and firmly with a metal pin, and any copy can easily be removed later without disturbing the others. Matching self-adhesive labels are provided to show the year. ELEKTOR binders can be ordered from our Canterbury office using the form overleaf. Price: £ 1.85 (incl. VAT and p&p). I I Subscription rates (up to and including no. 9 January 1976): Please note that no. 5 (July/ August) is a double issue; our 'Summer Circuits' issue. All prices include Postage. — Subscription to 8 issues (no. 1 included free) £3.60 — Trial subscription to 4 issues (no. 2 - no. 5) £2.00 — From no. 2 (February 1975) £3.60 — From no. 3 (April 1975) £3.15 — From no. 4 (June 1975) £2.70 — From no. 5 (July/August 1975) £2.25 — From no. 6 (September 1975) £ 1.80 — From no. 7 (November 1975) £ 1.35 — From no. 8 (December 1975) £0.90 — Single copies £0.45 2. FOLD HERE 1 Postage will be paid by Elektor Do not affix Postage Stamps if posted in Gt. Britain, Channel Islands or N. Ireland BUSINESS REPLY SERVICE Licence No. CU 203 ELEKTOR PUBLISHERS LTD., 6, Stour Street, Tl o r- D O O 5 z > r O z o H X m O O H H CANTERBURY CT1 2BR 3. 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NUMBER 1437 1443 1457 1465 A 1465B 1465C 1499 1527 1540 1590 1607 A 1607B 1621 A 1621 B 1621 C 1661 1668 4029 1 4029 2 4029 3 4039 4040A 4409 5027 A & B 5028 6019A 6025 1492 1563 1592 1620 4003 9076 9076/2A PRICE £1.65 £0.90 £0.60 £0.80 £0.55 £1.05 £1.20 £0.50 £1.05 £0.55 £1.15 £0.85 £0.70 £1.10 £0.55 £0.95 £0.95 £1.40 £1.40 £1.40 £0.50 £0.95 £1.50 £1.85 £1.25 £1.20 £1.40 £ 2.20 £1.25 £1.40 £0.70 £1.80 £1.70 £1.90 UK 92 UK 105/C UK 115 UK 165 UK 167 UK 195 UK 220 UK 230 UK 275 UK 285 UK 302 UK 305 UK 330 UK 345/A UK 555 UK 710/C UK 715 UK 780 UK 832 UK 855 UK 875 UK 930 UK 3009/00 UK 3009/10 UK 3009/20 TELEPHONE AMPLIFIER £ 8.27 F.M. MICROTRANSMITTER £8.07 HI FI AMPLIFIER 8W £4.50 R.I.A.A. EQUALIZED STEREO PREAMPLIFIER £ 5.64 STEREO PREAMPLIFIER RIAA & CCIR STANDARDS £ 6.98 MINIATURE AMPLIFIER 2W £3.67 SIGNAL INJECTOR £3.53 AM/FM ANTENNA AMPLIFIER .... £4.16 MIKE PREAMPLIFIER £6.98 VHF/UHF ANTENNA AMPLIFIER . . . . £8.87 RADIO CONTROL TRANSMITTER . . . £17.50 FM TRANSMITTER £3.38 GCX2 CHANNEL SPLITTING UNIT 1500 & 2500 HZ £8.34 SUPERHET RADIO CONTROL RECEIVER . £8.81 RADIO CONTROL STRENGTH METER . . £9.65 FOUR CHANNEL A.F. MIXER £11.12 PHOTOELECTRIC CELL SWITCH .... £7.74 ELECTRONIC UNIT FOR METAL DETECTOR £11.65 PHOTO ELECTRONIC REVOLUTION COUNTER £17.71 ELECTRONIC FUZZ BOX £ 7.23 CAPACITIVE DISCHARGE ELECTRONIC IGNITION UNIT NEG. EARTH £17.33 R.F. POWER AMPLIFIER 3 to 30 MHz. . . £2.65 METAL CABINET £6.26 METAL CABINET £6.08 METAL CABINET £6.98 ALL PRICES INCLUDE VAT PLEASE ADD 20p FOR P&P. I.C. INSERTION TOOL £1.45 each I.C. EXTRACTION TOOL £0.45p EACH BOOKS MULLARD FET'S .. .. £1.80 MULLARD MOS I.C.'S.. £2.00 MULLARD DATA BOOK 1974/75 £0.40 MULLARD TRANSISTOR AUDIO & RADIO CIRCUITS £1.80 ELEKTOR BACK ISSUES NOS. 1, 2,3,4 £0.35 NO. 5 ISSUE £ 0.70 L.E.D. DISPLAYS TYPE EP27 7 SEGMENT 4 FOR £5.00 723 FAIRCHILD 7 14 Pin D.I.L. Var. Voltage Reg. 65p FAIRCHILD 741 8 Pin D.I.L. Op. Amp ^V\T 33p NATIONAL semiconductor 14 Pin D.I.L. 2 Watt Audio Amp. £ 1.20 NATIONAL * semiconductor LM 1303 ^ MC * 131 OP 14 Pin D.I.L. 7 7 Stereo / Pre-Amp r £ 1.65 MOTOROLA 'Z— 14 Pin D.I.L. / Coiless \ Stereo Decoder f £ 2.30 > » 414 555V u±mt radio chip £ 1.25 SIGNETICS ' 8 Pin D.I.L. Timer 70p NATIONAL semiconductors 5314 24 Pin Clock Chip £4.35 3 ELECTRONICS 283 Edgware Road, London W2. Tel. 01-262 8614 Hours of business 9.30 - 6.00 Monday to Saturday callers welcome Motorola Semiconductors Ltd.. York House. Empire Way. Wembley. Middlesex. Telephone: 01-902 8836. European manufacturing facilities at Toulouse and East Kilbride. Distributors: Celdis Ltd.. Reading. East Kilbride: GDS (Sales) Ltd.. Slough. Dublin: Jermyn. Sevenoaks: Lock Distribution, Oldham: Semicomps Ltd.. Wembley.