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2. enclose cheque PO payable to DIRECT BOOK SERVICE for Please charge my Card Number Card Security Code the last three digits on or just below the signature strip Please send book order codes Card valid from date Please continue on separate sheet of paper if necessary Everyday Practical Electronics February 2009 69 PCB SERVICE Printed circuit boards for most recent EPE constructional projects are available from the PCB Service see list These are fabricated in glass fibre and are fully drilled and roller tinned Double sided boards are NOT plated through hole and will require vias and some components soldering to both sides All prices include VAT and postage and packing Add 1 per board for airmail outside of Europe Remittances should be sent to The PCB Service Everyday Practical Electronics Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Tel 01202 873872 Fax 01202 874562 Email orders epemag wimborne co uk On line Shop www epemag com Cheques should be crossed and made payable to Everyday Practical Electronics Payment in sterling only NOTE While 95 of our boards are held in stock and are dispatched within seven days of receipt of order please allow a maximum of 28 days for delivery overseas readers allow extra if ordered by surface mail Back numbers or photocopies of articles are available i
3. A Window To The World Rebuilding A Post war Aerodyne 301 Component Lore Switches s co radion gone ARTICLES on restoration and repair history circuit techniques personalities reminiscences and just plain nostalgia you ll find them all Plus features on museums and private collections and a full colour photo feature in every issue IT S MOSTLY about valves of course but solid state whether of the coherer and spark gap variety or early transistors also has a place FROM THE DAYS of Maxwell Hertz Lodge and Marconi to what was the state of the art just a few short years ago There is also a selection of free readers For Sale and Wanted advertisements in every issue Radio Bygones covers it all THE MAGAZINE is published six times a year and is only available by postal subscription it is not available at newsagents TO TAKE OUT a subscription or to request a sample copy please complete the form below and return it to RADIO BYGONES Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Tel 01202 873872 Fax 01202 874562 Web sites www radiobygones co uk www radiobygones com A SAMPLE COPY of Radio Bygones 9 75 Bygones Add 75p for overseas airmail postage SUBSCRIPTIONS post paid 1YEAR 2YEAR UNITED KINGDOM aae AMA UU S S REST OF EUROPE AIRMAIL 23 50 45 00 Please print clearly and check that you hav
4. O Sim o lt JUNCTION TEMPERATURE C Fig 1 1995 54 BS170 MOSFET gate threshold variation with temperature from Fairchild Semiconductor datasheet BS170 Rev C transistors after discussing some of the physics of the MOSFET and the origin of its threshold voltage MOSFET operation A full understanding of the operation of the MOSFET and other semiconductor devices and the influence of temperature on their characteristics and operation requires knowledge of atomic physics of solids and quantum statistical mechanics This is beyond the scope of Circuit Surgery and most circuit designers do not need a really detailed knowledge of the physics however some idea of device physics is very useful for understanding circuit operation datasheets and SPICE simulation A simplified cross section diagram of a MOSFET is shown in Fig 3 Conduction between source and drain in a MOSFET takes place in a narrow channel region under the gate The term lateral MOSFET is used to describe this structure which is used for low power devices as the current flows entirely through a horizontal plane The structure of power MOSFETs is different but the fundamental principles of operation are the same The basic operation of the N channel MOSFET as shown in Fig 3 is as follows If we apply zero low or negative gate source voltage the device is off because the N P N regions act as two back to bac
5. 0 50V O 3A Model 461 554 0 30V 0 10A Panel Meters High quality analogue panel meters class 2 zero point correction mirror scale Meter size 46 x 60mm Cutout size 38mm All meters 5 89 each Magnifying Desk Lamp A high quality scratch resistant magnifying glass fitted to a bal anced swivel arm and desk mount An integral flourescent tube provides illumination Magnification 3x Lens 120mm Tube 22W Daylight simulation Model 028 205 28 80 equipment for the Entertainment 7 Tel 0191 2514363 Station Road Ej PCB Production Laminates clad paper Single sided low cost paper composite board 100 x 160mm Board 0 58 100 x 220mm Board 160 x 233mm Board 220 x 233mm Board 8 x 12 Boar Copper clad glass fibre Single amp Double 1 6mm 305g m 100 x 160mm Singl ale 220 x 233mm Double 8 x 12 Double Photoresist Coated 1 6mm 35 micron Pre coated with a high quality photo resist layer Available in low cost paper composite or Glass fibre Single amp Double sided Other sizes also available Glass Fibre PCB Production Chemicals Aerosol Photoresist spray covers 2m Powder developer makes 1lt Powder developer makes 1011 Ferric Chloride Pellets makes 500ml Ferric Chloride Pellets makes 1It Ferric Chloride Pellets makes 5lt Clear Fine etch crystals makes 5lt Tin Plating Powder makes 11 Aerosol Flux spray Aerosol PCB Laquer spray Tools Cutters
6. M4 x 10mm SCREW NUTS AND STAR WASHERS Fig 2 the Altronics case will come with the main earth lugs mounted in place However if you re using a different enclosure here s how to install the chassis earth point Two nuts are used to permanently lock the assembly in place Make sure that it forms a sound electrical contact with the chassis mounting location and orientation It s mounted with its positive DC output at top right Chassis earth lugs Fig 2 shows the mounting details for the main chassis earth lugs This assembly consists of two double ended quick connect spade terminals which are bolted to the chassis using an M4 x 10mm machine screw two star washers and two nuts The second nut on top locks the first nut in place so that there s no possibility of the earth terminals coming loose The chassis supplied with the kit will come with the earth lugs mounted in position However if you are using a different case then you will have to remove the powder coating yourself To do this tempo rarily bolt one of the double ended quick connects to the chassis and use a pencil to outline the contact area The connector can then be unbolted and the powder coating removed using a sharp implement or a small grinding tool The two double ended earth lugs can then be bolted in position Be sure to do the nuts up nice and tight to ensure a reliable earth A second earth lug is mounted at the front of the ch
7. 0 0 O TINA Pro V7 Basic Flowcode V3 Hobbyist Student O Electronic Components Photos Version 1 1 E L1 Project Design Single User same only the licence for use varies i O Project Design Multiple User under 500 students 1 Project Design Multiple User over 500 students I fj I 0 0 a Bani eE EE E E aero Sees DIT POS COU TORNO vacate esdue ede csi attendee ae eet ndi DIE a Emu Ebr enclose cheque PO in sterling payable to WIMBORNE PUBLISHING LTD for O Please charge my Visa Mastercard Maestro Valid From Card expiry date Oad NO Maestro Issue No Card Security Code The last 3 digits on or just under the signature strip m um um um um Em EN 62 Everyday Practical Electronics February 2009 READ Oats Email editorial wimborne co uk ee Matt Pulzer addresses some of the general points readers have raised Have you anything interesting to say Drop us a line All letters quoted here have previously been replied to directly LETTER OF THE MONTH 5 Tuning in Dear EPE Ge
8. Next install the 3 way pin header the crystal and the two LEDs take care to orient these correctly We used a 10 WAY IDC TRANSITION CONNECTOR RED STRIPE 10 WAY IDC CABLE KEY eee 10 WAY KEYED IDC SOCKET SIDE VIEW Fig 7 here s how to assemble the IDC lead 18 red LED for LED35 and a green LED for LED34 Winding inductor L1 Inductor L1 is wound on a 28mm powdered iron core using 0 5mm enamelled copper wire Neatly wind on the 60 turns and twist the wires to gether to prevent the windings loosen ing then secure it in position on the board using two cable ties That done strip the insulation from the ends of the wires using a utility knife and solder them to the PC board The board can now be mounted in the small instrument case and secured with four M3 x 6mm screws You will need to cut holes in the rear panel for the IDC socket and for the cable entry for the screw terminal points Display board The commonly available display LEDs used for the tachometer are suit able for inside a car providing the sun does not shine directly on the display However they are not bright enough when operating in direct sunlight For this you will need sunlight readable 7 segment displays and high intensity LEDs The parts list has the details Begin the assembly by installing all the wire links Keep these straight and tight so that t
9. Notes Note that capacitors C1 and C3 are polarized as indicated by the sign at one end Breadboarding Components needed Integrated circuits IC1 162 IC3 type 7611 CMOS operational amplifier op amp I1 type 555 timer IC2 IC3 Thermistor TH1 NTC negative temperature coefficient disc type with a resistance of 5KQ at 25 C For example type TTC502A Light emitting diode LED1 suggest red Loudspeaker LS1 miniature 8 2 07160 impendance Capacitors C1 to C3 values 10uF axial electrolytic 25V C1 C3 10nF polyester C2 Potentiometer VR1 50kQ miniature preset type Resistors R1 to R8 values 47kQ R1 R2 R5 to R8 IMQ R3 220 2 All 0 25W carbon film Switch S1 On Off single pole single throw SPST Battery B1 9V and connecting leads Protobloc and wire links ov rei EMI o O O O O O O O O O Ooo aj iei O 8 0 0 0 0 99 0 6 06 O00 000 9 eee 00000 BATTERY Fig 5 2 Assembly of the Frost Alert on Protobloc e If unsure use the Circuit Tester described in Part 1 of this series to identify the anode lead for LED1 e None of the component values are critical except that it is advisable to use the values of TH1 1 as listed Use the recommended CMOS e LT op amp for IC1 not a 741 op amp Ini the 7
10. 12 rotational degrees between an even number of firings it prevents erratic RPM measurements We also set the tachometer to count between four successive firing pulses for engines with six cylinders and over This is to provide a sufficient count value especially at high RPM to en sure a high resolution calculation For the 4 digit display the fast updates are not required and so the update is slowed down to a more read able rate as set by the update counter Between display updates each RPM calculation is added together and the total is averaged before being dis played The display update period is one ofthe tachometer settings that can beadjusted Typically a 200ms update five times a second is satisfactory however update times from 0 510ms can be set in 2ms steps Circuit description The circuit can be divided into two sections Figs 3 and 4 which correspond to the control board and the display board The control section includes microcontroller IC3 and the LED display power supply involving ICA inductor L1 and transistor Q1 The display section incorporates the 32 LED bargraph the four 7 segment displays the shift LED the LDR and the display drivers IC1 and IC2 The control section of the circuit is shown in Fig 3 IC3 is the microcontrol ler that drives the data and clock lines for the display driver ICs It also accepts the tachometer signal from the engine and performs the calculations required
11. STEP 5 switch off and connect the supply leads 22V OV 22 for the righthand power amplifier to the power supply module STEP 6 remove the two fuses from the righthand power amplifier and install 1 5Q 5W resistors in their place ie one in series with the 22V rail and in series with the 22V rail The best way to do this is to solder these resistors across a couple of spare M205 fuses after first destroying the internal fuse wires First drill a hole in each end cap breaking the fuse wire in the process The resistor leads can then be bent to shape fed through the end caps and soldered see photos The modified fuses with their resis tors are now plugged into the fuse holders These 1 5Q resistors protect 34 the output transistors by limiting the current through them ifthere is a fault eg ifthe Vgg multiplier circuitry 010 is not functioning correctly STEP 7 wind trimpot VR1 on the right channel power amplifier fully anti clockwise switch on and check that the amplifier s output voltage ie between the loudspeaker terminals is less than 50mV If not check the base emitter voltage of each transistor in the ampli fier they should all be 0 6V to 0 7V Check also that the correct transistor is installed at each location and that they are all the right way round STEP 8 assuming the output voltage is correct monitor the voltage across one of the 1 5Q 5W resistors and wind trim p
12. amp Strippers We carry a wide range of specialist tools for the elec tronics industry including Side Cutters 130mm Low cost 115mm Draper 2 38 Wire Strippers 130mm Low cost 2 30 150mm Draper 5 5 86 11 99 Tools Ratchet Crimping Pliers High quality ratchet crimping pliers for various terminals including Automotive Data Power and Data connections Red Blue Yellow 80 j BNC TNC RF series 15 62 RJ11 12 amp 45 Series 11 76 Non 23 53 CK Tools Crimp Pliers Green Red Blue 3 Red Blue Yellow 0 24 2 5 crimps 0 5 6 crimps Non insulated crimps Cable Ribbon 7 0 127mm Grey ribbon cable on a 0 05 1 27mm pih with a red e miN ing stripe Supplied by 305mm 1ft or on full 30 5m 100ft reels Per 60 Way IDC Crimp tool CAT 5e Networking UTP Cable Conforms to CAT5E 100MHz standard ETA verified TIA EIA 568 B 2 305m Box 63 56 100m Reel 24 30 exc carriage RJ45 Outlet Kit Backing Box 2 Gang Plate RJ45 Module Blank Module Coloured id inserts 2 86ea 2 29 10 Tools Plastic punch down tool amp cable stripper Professional punch down IDC amp trim tool Outlets CAT5e Outlet Module 1Gang Plate 2 Mods 2 Gang Plate 4 Mods Module Blank 1 Module Blank 2 Module Blank 0 45 Other keystone outlets switches amp accessories avail able Patch amp Cross over leads from 0 5 Prices Exclude Vat 15 UK Carriage
13. and use Outlook Express for all your email requirements how to use the Windows Media Player 8 to play your CDs burn CDs with your favourite tracks use the Radio Tuner transfer your videos to your PC and how to use the Sound Recorder and Movie Maker How to use the System Tools to restore your system to a previously working state using Microsoft s Website to update your Windows set up how to clean up defragment and scan your hard disk and how to backup and restore your data How to successfully transfer text from those old but cherished MS DOS programs 514 7 99 INTRODUCING ROBOTICS WITH LEGO MINDSTORMS Robert Penfold Shows the reader how to build a variety of increasingly sophisticated computer controlled robots using the brilliant Lego Mindstorms Robotic Invention System RIS Initially covers fundamental building techniques and mechanics needed to construct strong and efficient robots using the various click together components supplied in the basic RIS kit explains in simple terms how the brain of the robot may be programmed on screen using a PC and zapped to the robot over an infra red link Also shows how a more sophisticated Windows programming language such as Visual BASIC may be used to control the robots Detailed building and programming instructions provided including numerous step by step photographs 288 pages Large Format 1 Tu uM 14 99 MORE ADVANCED ROBOTI
14. founder of semiconductor manufacturer Intel made a prediction now known as Moore s Law It states that the number of transistors on a chip will double about every two years thus increasing the power and reducing the cost of products made with semiconductor devices Brian Halla chief executive officer of National Semiconductor argues it is not universally applicable however Speaking last November at international Electronica trade show he declared Analogue does not follow Moore s Law Moore s Law is not about power efficiency it is only about more transistors There are smarter things for us to do now And analogue is what he predicted would create the next great growth cycle for the semiconductor industry Semiconductors implement everything he argued and new markets in renewable energy electric vehicles distributed healthcare and better battery management would all demand analogue semiconductors He summed up semiconductor industry is essential for everything and this spells a rebirth for the semiconductor industry Funny by gaslight Have you ever tried to read a newspaper or magazine by gaslight Probably not although firms like Camping Gaz still sell gas lighting systems using gas canisters and proper incandescent mantles There are also parts of London and Malvern and other towns I m sure where street lighting still uses gas The point making is that gas lighting has a strange green cast
15. minals towards the top and are again secured using 6g x 12mm countersink self tappers The 35A bridge rectifier can go in next Because it uses the chassis for heatsinking it s important to ensure good metal to metal contact It s mounting area should be completely free of powder coating if it isn t mark out the area and remove the powder coating using a small grind ing tool Now smear the underside ofthe 35A bridge rectifier BR1 with heatsink compound and bolt it to the chassis using an MA screw star washer and nut Fig 1 and the photos show BR1 s 26 RIGHT SPEAKER OUTPUT x 5 OUTPUT Cf Hm CABLE TIE SPEAKER PROTECTOR C Hm BOARD RECTIFIER BRIDGE AMPLIFIER LEFT AMPLIFIER INPUT EARTHING LUG O 22 NOTE ALL FEMALE SPADE QUICK CONNECTS MUST BE FULLY INSULATED NOT SHOWN FOR CLARITY LEFT CHANNEL HEATSINK ADHESIVE CABLE TIE DOWN POINT Everyday Practical Electronics February 2009 Constructional IEC MAINS INSULATE FROM CONNECTOR REAR PANEL GRN SLEEVE WITH HEATSHINK TUBING SEE TEXT SLEEVE SWITCH LEADS WITH HEATSHINK RIGHT TUBING SEE TEXT CHANNEL POWER AMPLIFIER RIGHT AMPLIFIER NYLON INPUT RIGHT CHANNEL PREAMP amp VOLUME CONTROL BOARD HEATSINK Everyday Practical Electronics February 2009 21 2 x DOUBLE ENDED QUICK LET CASE BASE
16. pot is not used This avoids placing strain on the pot s soldered joints and in any case is unnecessary since the pot s ferrule is also secured to the front sub panel Before mounting the preamp fit a flat washer over the pot s threaded ferrule That done fit the three 25mm tapped spacers then slip the preamp board into position and secure it to the front sub panel by fitting the nut anda shakeproof washer to the pot Do this nut up firmly but don t over tighten it to avoid stripping the thread Finally the three spacers can be se cured to the chassis using M3 x 6mm machine screws and washers The three indicator LEDs and the IR LED on the preamp board all go through a cutout in the front sub panel Provided you ve installed them cor rectly as shown in Part 4 last month they should all line up neatly with their respective holes when the front panel is later installed Note that the photos show these parts going through separate holes in the front sub panel The chassis supplied for kits will feature a large cut out in the sub panel instead Note also that ifthe infrared receiver module IRD1 has a metal shield then it must be insulated from the front panel see p36 Jan 09 Power supply module The power supply board is next on the list but first you have to add some extra spade connectors First you need to install three extra single ended connectors at the DC output end of the board to go with the e
17. s payable to Quasar Electronics Please visit our online shop now for full details of over 500 electronic kits projects modules and publications Discounts for bulk quantities Quasar Eled tronics Limited PO Box E Bishops Stortford CM23 4WP United Kingdo Tel 08717 177 168 03 496 imn ics com Fax 07092 E mail s Web www VISA Electron SOLO QUASAR electronics Get disc In PIC amp ATMEL Pr grammers e have a wide range of low cost PIC s ATMEL Programmers Complete range and ocumentation available from our web site Programmer Accessories 0 pin Wide ZIF socket 7IF40W 14 95 8Vdc Powersupply PSU010 18 9 eads Parallel LDC136 3 95 Serial LDC441 3 95 USB LDC644 2 95 NEW USB amp Serial Port PIC Programmer USB Serial connection 8 Header cable for ICSP T4 Free Windows soft ware See website for PICs supported ZIF Socket and USB lead extra 18Vdc Kit Order Code 3149KT 39 95 Assembled Order Code AS3149 49 95 NEW USB All Flash PIC USB PIC programmer for all Flash devices No external power supply making it truly portable Supplied with box and Windows XP Software ZIF Socket and USB lead not incl Assembled Order Code AS3128 44 95 Assembled with ZIF socket Order Code AS3128ZIF 59 95 PICALL ISP PIC Programmer Will program virtually a
18. the associated LED lights The prototype Simple Dice assembled on Protobloc a score of 6 is represented by a jumbo LED Note C1 and LED ballast resistor R4 are missing in this photo On a roll The roll ofthe dice is accomplished n by pressing push to make switch 52 to generate the clock pulses These are generated at a rapid rate and all of the LEDs appear to be lit Upon releasing 52 one of the six selected outputs stays high and the associated LED is lit To ensure that a player cannot anticipate when a particular LED re mains lit the astable operates at a high frequency determined by the values of resistors R1 and R2 and capacitor C1 Thus when 52 is pressed all the H rea Fig 5 3 Simple Dice circuit diagram Construction brief To ensure trouble free assembly you should try and follow these basic guidelines Always use single core 0 6mm diameter plastic sleeved wire for wire links not thicker The ends of the wire should be stripped of plastic for about 8mm The use of thicker wire can permanently damage the springy sockets underneath each hole Never use stranded wire it can fray and catch in the sockets or a strand can break off and cause unwanted connections below the surface of the breadboard It is very important to make sure that the bared ends of link wires and component leads are straight before inserting them into the breadboard Kinks in the wire will catch in the springy clip
19. video enhancer improved video enhancer video fader horizontal wiper improved video wiper negative video unit fade to grey unit black and white keyer vertical wiper audio mixer stereo headphone amplifier dynamic noise reducer automatic fader pushbutton fader computer control interface 12 volt mains power supply 115 5 45 288 pages 124 pages All prices include UK postage for postage to Europe air and the rest of the world surface please add 2 per book For the rest of the world airmail add 3 per book CD ROM prices include VAT and or postage to anywhere in the world Send a PO cheque international money order sterling only made payable to Direct Book Service or card details Visa Mastercard or Maestro to DIRECT BOOK SERVICE WIMBORNE PUBLISHING LIMITED SEQUOIA HOUSE 398a RINGWOOD ROAD FERNDOWN DORSET BH22 9AU Books are normally sent within seven days of receipt of order but please allow 28 days for delivery more for overseas orders Please check price and availability see latest issue of Everyday Practical Electronics before ordering from old lists For a further selection of books see the next two issues of EPE Tel 01202 873872 Fax 01202 874562 E mail dbs wimborne co uk Order from our online shop at www epemag com BOOK ORDER FORM milla ipi TR TRENT Address Post code AONA aean E Telephone
20. 10 20 dB 50 2 1GHz attenuator set 39 051 50 1GHz feedthrough terminator 9 50 The new accessories are available from local distributors or direct from Pico Technology at http accessories picotech com ENHANCED 8 B T PIC CORE Microchip has announced its enhanced mid range 8 bit PIC microcontroller core MCU architecture supporting PIC12 and PIC16 MCUs with feature and peripheral improvements including more program and data memory deeper enhanced hardware stack additional reset methods 14 additional programming instructions including efficiency optimisations resulting in code size reductions increased peripheral support reduced interrupt latency The enhancements provide users with a performance boost of up to 50 and code size reductions of up to 40 Peripheral support includes Microchip s mTouch module for touch sensing user interfaces LCD displays multiple analogue to digital converters ADCs and pulse width modulation PWM modules additional timers and analogue comparators Additional feature enhancements include increased memory support with program flash addressability up to 56KB and data RAM up to 4KB With 14 additional instructions giving a total now of 49 the enhanced core optimises program code and data handling which reduces code space and increases efficiency with fewer clock cycles It also provides the ability to migrate with minimal effort among existing mid range PIC MCU
21. 168 62 62 The PC also has a built in wired Ethernet port but there is nothing currently connected to it so the command does not bother to show the details Below that the route command shows a lot more information It explains the different ways in which your computer can connect onward to other devices through different gateways Gateways are typically other PCs or routers which can bridge your connection from your local network out onto other networks The most interesting line is the first which shows that our computer uses 192 168 62 62 as a gateway In this case it is the local private address of the author s router Routers are intelligent pieces of electronics and have a small high performance microcontroller inside them They too have a TCPIP stack inside and virtually all provide Ethernet adapter Wireless Network Connection Gonnection specific DHS Suffix IP Address Subnet Mask Default Gateway Ethernet adapter Local firea Connection Media State print 1 2 HH 11 5 F1 25 63 aH di 32 69 ic Active Routes Hetmask z 192 168 62 62 209 209 209 6 192 168 62 1 Media disconnected 5 TCP Loopback interface Atheros AH R5HBH5G Wireless Network Adapter Realtek HTL8137 81Hx Family Fast Ethernet Gateway Interface Network Destination 4 6 6 8 4 6 6 8 192 168 62 1 168 62 62 255 0 0 0 127 8 8 1 127 6 8 1 255 255 0 0 192 168 62 62 2 168 62 62 255 255 255 0 19
22. 2 50 less than 1kg Cullercoats 65 50 50 greater than 1kg or gt 30 x Fax 0191 2522296 Tyne amp Wear Cheques Postal orders payable to sales esr co uk NE30 4PQ ESR Electronic Components Ltd PLEASE ADD CARRIAGE amp VAT TO ALL ORDERS Web 5 Editorial Offices EVERYDAY PRACTICAL ELECTRONICS EDITORIAL Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Phone 01202 873872 Fax 01202 874562 Email enquiries epemag wimborne co uk ite www epemag com See notes on Readers Technical Enquiries below we regret technical enquiries cannot be answered over the telephone Advertisement Offices Everyday Practical Electronics Advertisements Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Phone 01202 873872 Fax 01202 874562 Email stewart kearn wimborne co uk r editor f New Year since 1 becam ah the team at ion lieve but it s now 2 ont working wit zine 5 to be first 12 ate maga 7 e 1 5 hard hly enjoyed i produce a first appreciate t M p b publishing 5 11 4 Ly E O O AVAILABILITY Copies of EPE are available on subscription anywhere in the world see opposite and from all UK newsagents distributed by SEYMOUR EPE can also be purchased from retail magazine outlets around the world An Internet online version can be
23. 24 95 Additional D81820 Sensors 3 95 each E items are available in kit form KT suff or re assembled and ready for use AS prefix 177 4 Ch DTMF Telephone Relay Switcher Call your phone num ber using a DIMF phone from anywhere in the world and re motely turn on off any of the 4 relays as de sired User settable Security Password Anti Tamper Rings to Answer Auto Hang up and Lockout Includes plastic case 130 x 110 x 30mm Power 12Vdc Kit Order Code 3140KT 54 95 Assembled Order Code AS3140 69 95 8 Ch Serial Port Isolated I O Relay Module Computer controlled 8 channel relay board 5A mains rated relay outputs and 4 opto isolated digital inputs for monitoring switch states etc Useful in a variety of control and v sensing applications Programmed via serial port use our new Windows interface termi nal emulator or batch files Serial cable can be up to 35m long Includes plastic case 130x100x30mm Power 12Vdc 500mA Kit Order Code 3108KT 54 95 Assembled Order Code AS3108 64 95 Infrared RC 12 Channel Relay Board F Control 12 onboard relays with e included infrared remote con trol unit Toggle or momentary 15m range 112 x 122mm Supply 12Vdc 0 5A Kit Order Code 3142KT 47 95 Assembled Order Code AS3142 59 95 Audio DTMF Decoder and Display Detect DTMF tones from tape recorders receivers two way radios et
24. 5400 5 plus postage amp packing 3 Control ee or receive alert notification from anywhere By sending plain text messages this kit will allow you to control up to eight devices At the same time it can also monitor four digital inputs It works with old Nokia handsets such as the 5110 6110 3210 and 3310 which can be bought inexpensively if you do not already own one Kit supplied with PCB pre programmed microcontroller and all electronics components with clear English instructions brightest LEDs available in the world They offer up to 120 lumens per unit and will last up to 100 000 hours This kit allows you to power the fantastic 1W 3W and 5W Luxeon Star LEDs from 12VDC This means that you can take advantage of what these fantastic LEDs have to offer and use them in your car boat or caravan Kit supplied with PCB and all electronic components FLICKERING FLAME LIGHTING KIT KC 5234 4 95 plus postage amp packing This lighting effect uses a single 20 watt halogen lamp the same as those used for domestic down lights to mimic its namesake Mounted on a compact PCB it operates from 12V DC and uses just a handful of readily available components Use it for stage performances or for unique lighting effects at home e Requires Nokia data cable which can be readily found in mobile phone accessory stores As published in EPE March 2007 E TEMPERATURE SWITCH KIT KG 9140
25. BBC from a staff of four up to a Corporation of several hundred Brian Hennessy s book also describes the devlopment of broadcasting equipment the search for premises and looming bankruptcy before ending with the emergence of a firmly established Chartered Corporation the BBC Meticulous research over many years over a hundred photographs plans and diagrams as well as interviews with many of those who were there at the time make this a valuable and original work for those involved in media studies for radio enthusiasts or simply for those interested in radio and the fascinating story of the emergence of broadcasting 436 pages Order code EBB 26 00 PRACTICAL ELECTRONIC FILTERS Owen Bishop This book deals with the subject in a non mathematical way It reviews the main types of filter explaining in simple terms how each type works and how it is used The book also presents a dozen filter based projects with applications in and around the home or in the constructor s workshop These include a number of audio projects such as a rythm sequencer and a multi voiced electronic organ Concluding the book is a practical step by step guide to designing simple filters for a wide range of purposes with circuit diagrams and worked examples Order code 299 5 45 188 pages ELECTRONIC PROJECTS FOR EXPERIMENTERS R A Penfold Many electronic hobbyists who have been pursuing their hobby for a number of years seem to suffer
26. Check the 230V wiring to the IEC socket mains transform er and mains switch to ensure all is correct In particular the Everyday Practical Electronics February 2009 Constructional Ditching the preamp and using a conventional volume pot instead One of the options that you have in building this unit is to ditch the Preamplifier amp Remote Volume Control module and LEFT CHANNEL INPUT SOCKET use a dual 10k log pot as the volume control instead This option would typically be used if you wanted to use a CD TO LEFT POWER AMP INPUT player to drive the power amplifier modules the signal output from a CD player is usually but not always sufficient to drive the amplifier modules to full power output The advantage of this scheme is that you save money ie the cost of the preamplifier and construction time But there are a couple of disadvantages First as mentioned last month using a simple volume control varies the input impedance to the power amplifiers thereby slightly degrading the signal to noise ratio And second your CD player may not he able to drive the amplifiers to full output power on CDs that give below average output signal levels Another disadvantage is that you no longer have the con venience of remote volume control If you do want to omit the preamplifier Figs 3 and 4 show how it s done As shown the incoming left and right channel signals are fed to the top of the pot and the attenuated si
27. Daily News always given thought to using cameras to restore sight to the blind This 1s a little different more like James Bond stuff But Vlach has no desire to intrude on other people s privacy with her eyecam There are amazing other possibilities she asserts one being to record her entire life from now on or even shoot a reality TV show from her eye s perspective She says she will let inspiration strike once she has the device 23 and on the past Roy Want a senior principal engineer at Intel is assured that it s entirely possible to build a wireless camera to fit inside Vlach s prosthetic and link it to a smart phone that could transfer the video to another phone a TV studio or a computer In a world where eyecams were common they might serve a kind of computerised backup to people s memories he said You d never need to forget anything again you d never lose anything You could ask it for instance Where was the last time I saw my car keys The Test amp Measurement World website notes that 1f the project is a success it could not only lead to medical advancements for the blind but also to creating a widespread innovation to digitise people s memories by recording everything for them to refer back to If so one hopes the manufacturers can agree a single common format The video to brain interface may take some development too Moore s Law queried Back in 1965 Gordon Moore a co
28. Data etc PRACTICAL SKILLS Learn how to identify Electronic Components Avoid Static Hazards Carry Out Soldering and Wiring Remove and Replace Components TEST EQUIPMENT How Choose and Use Test Equipment Assemble a Toolkit Set Up a Workshop and Get the Most from Your Multimeter and Oscilloscope etc SERVICING TECHNIQUES The Manual includes vital guidelines on how to Service Audio Amplifiers The Supplements include similar guidelines for Radio Receivers TV Receivers Cassette Recorders Video Recorders Personal Computers etc TECHNICAL NOTES Commencing with the IBM PC this section and the Supplements deal with a very wide range of specific types of equipment radios TVs cassette recorders amplifiers video recorders etc REFERENCE DATA Diodes Small Signal Transistors Power Transistors Thyristors Triacs and Field Effect Transistors Supplements include Operational Amplifiers Logic Circuits optoelectronic Devices etc MODERN ELECTRONICS MANUAL m The essential reference work for everyone studying electronics 9 Over 800 pages 9 In depth theory 9 Projects to build 9 Detailed assembly instructions 1 Full components checklists Extensive data tables 9 Manufacturers web links 9 Easy to use Adobe Acrobat format 9 Clear and simple layout 9 Comprehensive subject range 9 Professionally written Supplements BASIC PRINCIPLES Electronic Components and their Characteristics Circuits Using Passive C
29. IC1 and IC2 include dimming inputs The dimming control circuitry comprises LDR1 and transistors Q2 and Q3 along 1 high intensity 5mm orange LED LED33 1 10V 1W Zener diode 201 1 1N5404 diode D1 1 FR302 100V 3A fast recovery diode D2 2 1N4148 switching diodes D3 D4 Capacitors 2 470mF 25V low ESR PC electrolytic 1 220mF 10V PC electrolytic 2 100mF 16V PC electrolytic 2 10mF 16V PC electrolytic 1 2 2mF 63V PC electrolytic 1 100nF MKT polyester 2 47nF MKT polyester 1 10nF MKT polyester 2 1nF MKT polyester 1 470pF ceramic 2 22pF ceramic Resistors 0 25W 196 except where stated 1 100k 2 1 1 2kQ 1 22kQ 1W 5 7 1kQ 10kQ 1 2200 2 4 7kQ 2 1002 1 3 3k 1 0 102 5W 1 2 2kQ Potentiometers 1 50kW horizontal mount trimpot VR1 2 20kW horizontal mount trimpots VR2 VR3 2 200kW horizontal mount trimpots VR4 VR5 1 5 horizontal mount trimpot VR6 Reproduced by arrangement with SILICON CHIP magazine 2009 www siliconchip com au with the associated trimpots VR2 to VR6 This circuit is operated from a 10V supply derived from the 2200 dropping resistor and Zener diode ZD1 Transistors Q2 and Q3 act as voltage followers where the emitter voltages are 0 7V above the base volt age The emitter voltages therefore follow the voltage across the LDR With high ambient light the LDR is a low resistance and the voltage across the LDR is about 1V The emitters of Q2 and Q3 ar
30. IC2 is a timer IC wired as alow frequency astable causing it to oscillate at a frequency set by the values 48 Fig 5 1 Frost Alert circuit diagram Everyday Practical Electronics February 2009 Component Info IC1 type 7611 CMOS op amp IC2 IC3 type 555 timer IC Viewed from the top an indented dot and a half moon shape at one end in dicates pin one The pins are numbered anti clockwise end ing at pin 8 opposite pin 1 TH1 disc thermistor 5kQ resistance at 25 C Example type TTC502A Has long leads and can be connected either way round in the circuit LS1 loudspeaker The two wires to the loudspeaker can be connected to the circuit ei ther way round The speaker will need two 0 6mm plastic covered wires attached to its terminals of capacitor C1 and resistors R5 and R7 This frequency is about 1Hz and is monitored by the flashing of LED1 Each time IC2 output pin 3 goes high so turning on LED1 it enables the sec ond astable based on IC3 via its pin 4 When IC2 pin 3 falls to OV it switches off IC3 The frequency of the astable that is centred on IC3 is 100 times higher than that based on IC2 so that the two astables provide a continuous beep beep sound from LS1 The circuit is adjusted so that it responds to a temperature of 0 C by immersing the thermistor in melting ice to make sure it is at 0 and ad justing preset VR1 so that the alarm is just triggered
31. In the example system of Fig 5 the two lines are normally low under standby conditions so taking one or both of them high for a period of time could be used as a reset signal to the receiving device The receiving equipment will usually be based on a microcontroller so this type of checking will require a few lines of additional program code rather than any additional hardware 5232 Output 1 Ha232C Output RS232C 1 5232 2 HLCMOS imant 1 TTL CMOS Input 2 TTLCMOS Output 1 ITTLCMOS _ Output 2 Fig 4 The MAX202 provides two line drivers plus two line receivers but requires no awkward or expensive inductors and operates from a single 45V supply Everyday Practical Electronics February 2009 45 Readers Circuits WIN A PICO PC BASED OSCILLOSCOPE WORTH 799 200MHz Analogue Bandwidth Dual Channel storage Oscilloscope pectrum Analyser Frequency Meter Multimeter USB Interface i you have a novel circuit idea which would be of use to other readers then a Pico Technology PC based oscilloscope could be yours After every 20 published IU circuits Pico Technology will be awarding a PicoScope 3206 digital storage oscilloscope for the best IU submission In addition a PicoScope 2105 Handheld Scope worth 199 will be presented to the runner T Fuel Guage Interface circuit shown in Fig 1 was developed to assist in the display of fuel level on a rally c
32. OHOHOHOH HOH HOH HONO HOH NOH NOR HORE HONOR OROROH B Postcode 2222202 enclose cheque P O bank draft to the value of please charge Visa Mastercard Maestro Card Security Code The last 3 digits on or just under the signature strip EO IME Expiry Maestro Issue No Visa SEND Everyday Practical Electronics Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Tel 01202 873872 01202 874562 Email orders epemag wimborne co uk Payments must be by card or in Sterling cheque or bank draft drawn on a UK bank Normally supplied within seven days of receipt of order Send a copy of this form order by letter if you do not wish to cut your issue A See eee eee 5 pw ee BECOME A PIC WIZARD WITH THE HELP OF Everyday Practical Electronics February 2009 ES 2 CIRCUIT SURGERY REGULAR GLINIC BY IAN BELL MOSFET physics and parallel transistors Ree EPE Chat Zone www chatzo nes co uk contributor Gerry recently posted the following question about MOSFETs Metal Oxide Semiconductor Field Ef
33. System JUY 08 PIC MIDI Sound Wave Generator Galactic Voice Coolmaster AUGUST 08 Four Channel A V Selector DC Relay Switch For High Current Loads Versatile Temperature Switch 70 PRO ECTTITLE ORDERCODE COST Mains Monitor Monitor 679 nterface 680 SEPTEMBER 08 Magnetic Cartridge Preamplifier 681 Super Speedo Corrector 682 Ultrasonic Eavesdropper 683 S Video To Composite Video Converter double sided 684 OCTOCBR 08 Inteligent Car Air Conditioner Controller Cordless Power Tool Charger Controller 20W Class A Amplifier Module Left Channel Right Channel PSU 08 50MHz Frequency Meter Mk 2 Version 1 Version 2 Version 3 Variable Turbo Boost Control Fuel Cut Defeater DECEMBER 08 Christmas Star 20W Class A Amplifier Speaker Protector amp Muting Radar Speed Gun Head Display JANUARY 09 20W Class A Amplifier Preamplifier and Remote Volume Control 1000 1 UHF Prescaler double sided FEBRUARY 09 1 3V To 22V Regulated Power Supply LED Tachometer Control Board Display Board EPE SOFTWARE All software programs for EPE Projects marked with a star others previously published downloaded free from the Library on our website accessible via our home page at www epemag com PCB MASTERS PCB masters for boards published from the March 06 issue onwards can also be downloaded from our website ww
34. The build up of this charge tends Fig 2 In a perfect world transistors in parallel would behave like a larger more powerful transistor In practice this is easier with FETs than it is with BJTs Everyday Practical Electronics February 2009 SOURCE CHANNEL DRAIN SOURCE CURRENT Fig 3 Simplified cross section of a lateral MOSFET used for low power applications to inhibit further movement of the charge carriers Thus the formation of the depletion region is a balance between the mechanisms of diffuse and recombine and the opposing build up of separated charges reverse biased diode enhances the formation of the non conducting depletion region so no current flows When a diode is forward biased a certain voltage has to be applied before the depletion region is reduced to the point at which the diode can conduct The separated charges produce a potential barrier which must be overcome before conduction takes place hence the typically 0 6V to 0 7V required to switch on a silicon diode MOSFET depletion regions In an N channel MOSFET with low zero or negative voltage applied to the gate there is a depletion region all around the source and drain and directly underneath the gate So like a reverse biased diode no current can flow If we apply a positive gate source voltage the electrostatic attraction of this gate voltage will pull negatively charged electrons from the nearby silicon main
35. a few minutes I had the eye in the machine Then I turned on the current and the waves carrying television were broadcast from the aerial The essential image for television passed through the eye within half an hour after the operation On the following day the sensitiveness of the eye s visual nerve was gone The most sensitive optical substance known is the nerve of the human eye I had to wait a long time to get the eye because unimpaired ones are not often removed by surgeons Nothing was gained from the experiment It was gruesome and a waste of time Eye on the future Eighty one years later the idea is reborn in reverse well nearly A one eyed San Francisco artist is trying to replace her missing eye with a webcam and technical experts say it s possible To be fair they are not proposing to connect the artificial eye to her brain but to computers Tanya Vlach is a 35 year old artist who lost her eye in a 2005 car accident She wears a realistic replica eye made of acrylic but feels she could do far more than this She wants scientists to build an eyecam for her prosthesis that can dilate with changes of light and allow her to blink to control its zoom focus and on off switch She explains There have been all sorts of cyborgs in science fiction for a long time and I m sort of a sci fi geek With the advancement of technology I thought Why not Her surgeon R William Danz told the New York
36. are supplied with specified board components quality fibreglass tinned PCBs and February 09 have clear English instructions Watch this space for future featured kits Electronics FULL FUNCTION SMART CARD AC DC CURRENT CLAMP READER PROGRAMMER KIT METER KIT FOR DMMS 15 95 Fi 8 75 Program both the microcontroller and EEPROM in the popular gold silver and A great low cost alternative to expensive current clamp meters _ emerald wafer cards Card used needs to conform to 150 7816 standards It uses a simple hall effect sensor and iron ring core setup and Powered by 9 12 VDC wall adaptor or a 9V battery Instructions outline connects to your digital multimeter It will measure AC and DC software requirements that are freely available on the internet Kit supplied 4 current and has calibration dial to allow for magnetising with PCB wafer card socket and all electronic components of the core Much cheaper than pre built units Kit supplied with PCB clamp case with silkscreened e PCB measures 141 x 101mm gt 5 2 front panel amp all electronic components wee RADAR SPEED GUN MKII 29 00 6 00 13 25 If you re into any kind of This versatile kit will allow you to monitor the battery voltage Effect and depth controls allow you to vary the voice to racing like cars bikes the airflow meter or oxygen sensor in your car The kit simulate everything from to the hy
37. as it may I would still like to register for the EPE Chat Zone if I may I purchase your fine magazine if and when it is available here at great expense to keep me aware of what is going on Hoping you can help shed some light on this situation Jason Mitchell via email Alan replied to Jason Many thanks for your email which is sorry account of your trials and tribulations I am dismayed to read of your difficulties I have some close contacts in Cape Town and I have been told about the problems that are a regular feature of South African telecoms Some spamblocking services eg http www sorbs net reference IP addresses and domains striving to blacklist any sources of spam They can affect genuine emails that are screened out erroneously but it is usually quite rare There is also the possibility of overzealous spamfilters filtering out mail on the recipient s system I do however email my South African correspondents routinely without any problem so I think that the fears of SA emails being regularly screened out are probably unfounded As regards the EPE Chat Zone even though we use robust forum software that has never been compromised by hackers this has been a constant target for spammers who try to post spam into Everyday Practical Electronics February 2009 the forums hard to believe I know Only about 1 of applications are genuine and consequently all new applications have to be pre appr
38. connects to the outer collar The other ends of these cables can then be trimmed to length and con nected to screw terminal blocks CON2 and CON4 on the preamplifier Be sure to tin the leads as before and again make sure the connector screws are done up tightly Loudspeaker cabling The loudspeaker leads both to and from the loudspeaker protector module are run using heavy duty 90 0 18 speaker cable The cables are terminated at both ends using female spade connectors and must be routed exactly as shown in Fig 1 and the photos In particular note the path for the loudspeaker cable from the right chan nel power amplifier This must be kept as far away as practical from the mains wiring between the IEC socket and the power transformer As shown it runs around the chassis earth terminal and then runs along the bottom section of the rear panel behind the transformer to the Everyday Practical Electronics February 2009 If your infrared receiver module has a metal shield like this one then be sure to insulate it from the front panel as described last month The AC Sense leads from the loud speaker protector module are terminated in piggyback crimp connectors at the bridge rectifier end as shown here loudspeaker protector module The cable is anchored in position using several adhesive cable tie mounts Two of these are attached to the bottom of the rear panel while the third sits in front of the chassis
39. drivers and receivers to provide an inversion and that the software must be designed to take this into account Synchronous link An RS232C uses a form of asynchronous serial communication which means that the link can be provided using just one signal line plus a ground connection or two lines plus a ground connection if two way communication is required The two ends of the system are synchronised using additional signals on the data lines and by using a standard rate when sending data Provided the receiving system is set up to interpret the synchronising signals correctly and it is also set to receive data at the correct rate data will normally be transferred without any corruption of the data The alternative approach is to use a synchronous link and the rate at which data is sent is not standardised with this method There are no baud rates to contend with or word formats either A slight drawback of the synchronous approach is that each link requires two signal lines plus a ground connection for one way operation or four lines plus a ground connection for a two way system There are two handshake lines on each serial port that are under software control which is sufficient for a basic synchronous output With a simple synchronous link the two signal lines are used to carry the data and a clock signal The clock signal is not a regular series of pulses and it is not a clock signal of the type used to control most digi
40. earth lugs Mounting the transformer The toroidal mains transformer can now be bolted into position This transformer is supplied with two neoprene rubber washers one sits under the transformer ie be tween the transformer and chassis while the other sits on top A metal cup washer is then placed over the top rubber washer and the whole assembly secured using a large bolt that passes up through the centre of the transformer Before installing the mounting bolt check that the powder coating has been cleared from around its hole at the bot tom of the chassis this is necessary to ensure the bolt is correctly earthed Now install the bolt and do the nut up finger tight then rotate the transformer so that its yellow secondary lead is exactly in line with the GND centre connection on the adjacent power supply board Constructional Project 1 custom pre punched steel case with screened front and rear panels Altronics 1 32mm black aluminium knob with grub screw 1 16 16V 160VA magnetically shielded toroidal transformer Altronics MA 5417 1 SPST 10A 250V AC rocker switch 1 chassis mount fused male IEC socket 1 4A 250V AC slow blow fuse M205 1 230V AC 3 pin IEC mains power lead 3 6 3mm double ended chassis mount spade lugs 5 6 3mm single ended chassis mount spade lugs 40 6 3mm female spade fully insulated connectors 2 piggyback crimp connectors 1 red RCA phono plug 1 black RCA phono plug 2 chassis
41. envelope or a self addressed envelope and international reply coupons We are not able to answer technical queries on the phone PROJECTS AND CIRCUITS All reasonable precautions are taken to ensure that the advice and data given to readers is reliable We cannot however guarantee it and we cannot accept legal responsibility for it A number of projects and circuits published in EPE employ voltages that can be lethal You should not build test modify or renovate any item of mains powered equipment unless you fully understand the safety aspects involved and you use an RCD adaptor COMPONENT SUPPLIES We do not supply electronic components or kits for building the projects featured these can be supplied by advertisers We advise readers to check that all parts are still available before commencing any project in a back dated issue ADVERTISEMENTS Although the proprietors and staff EVERYDAY PRACTICAL ELECTRONICS take reasonable precautions to protect the interests of readers by ensuring as far as practicable that advertisements are bona fide the magazine and its publishers cannot give any undertakings in respect of statements or claims made by advertisers whether these advertisements are printed as part of the magazine or in inserts The Publishers regret that under no circumstances will the magazine accept liability for non receipt of goods ordered or for late delivery or for faults in manufacture TRANSMITTERS BUGS
42. from the dreaded seen it all before syndrome This book is fairly and squarely aimed at sufferers of this complaint plus any other electronics enthusiasts who yearn to try something a bit different The subjects covered include Magnetic field detector Basic Hall effect compass Hall effect audio isolator Voice scrambler descrambler Bat detector Bat style echo location Noise cancelling LED stroboscope Infra red torch Electronic breeze detector Class D power amplifier Strain gauge amplifier Super hearing aid Order code BP371 5 45 PRACTICAL FIBRE OPTIC PROJECTS R A Penfold While fibre optic cables may have potential advantages over ordinary electric cables for the electronics enthusiast it is probably their novelty value that makes them worthy of exploration Fibre optic cables provide an innovative interesting alternative to electric cables but in most cases they also represent a practical approach to the problem This book provides a number of tried and tested circuits for projects that utilize fibre optic cables The projects include Simple audio links F M audio link P W M audio links Simple d c links P W M d c link P W M motor speed control RS232C data links MIDI link Loop alarms R P M meter All the components used in these designs are readily available none of them require the constructor to take out a second mortgage Order code 74 5 45 138 pages 132 pages STARTIN
43. into your favourite word procesing or DTP package behaviour It is so simple to use that it will take you less than 10 minutes to make your first digital design It is so powerful that you will never outgrow its capability e Software TINA includes the following Virtual Instruments Oscilloscope Function Generator Multimeter Signal Analyser Bode Plotter Network Analyser Spectrum Analyser Logic Analyser Digital Signal Generator XY Hecorder Flowcode V3 Hobbyist Student For details on Flowcode see the previous page for simulating digital logic circuits e Create I your own macros highly scalable Create This offer gives you two seperate CD ROMs in DVD style cases the software will need registering FREE with Designsoft TINA and your own circuits components and i c s Matrix Multimedia Flowcode details are given within the packages Easy to use digital interface A Animation brings circuits to life e Vast library of logic macros and 74 series i c s with data sheets e Powerful tool for designing and learning Hobbyist Student 44 inc VAT PROJECT DESIGN WITH CROCODILE TECHNOLOGY EOD T DER An Interactive Guide to Circuit Design Site Licence 599 plus VAT An interactive CD ROM to guide you through the process of circuit design Choose from an extensive ELECTRONIC range of input process and output modules including CMOS Logic Op Amps PIC PICAXE Remote Control Modules IR and Radio Transis
44. is provided via the 3 3kQ resistor to pin 5 and the 1 2kQ Everyday Practical Electronics February 2009 bug Jo ejdsrp ay pue 031 jndur ay sassav01d sm 1d OIJUOIOIIIU 88491014 SI EDI uo paseq sr FMI AY 26 814 gt V V Im GILINOHIVL 031 14510 1 00 yOVSNI ZOEN ZZ LAZ 87 LYNL YTIOULNOD c D E E H i i V ol 4426 4426 Oo 13s l 5 cS LS ZHWOZ i V dfi NMOd 159501 303 38 AVW zz LOdNI T3 3l1 O MOI CAI 717 y y O M IIN bn INdNI i 3901 ov UN D AOL x 4001 AOL 3 4 8849124 zaz NIA HOH o 891 A 81 ca zi JOL Age tee ML AZZ ta QNO c s ADL NI YAWN Jl el TT mool 170 OL NI 12 19 R S 100V6cWl 1933 zol za ALY G31 120 62 0 ONIWWIG HIST ee oe wwgz NO Mod 0 JO AS SNL 09 11 6001 T MI 2 97 gt da MOI SIQONY 6006 Gee OL A AO Y lt VOVSNL AZL 11 ta 13 Everyday Practical Electronics February 2009 Constructional Project Dant sali sS EDETachjomjjtel 1 P
45. knowledge required e Mathematics is kept to a minimum and all calculations are explained e Clear circuit simulations 60 Everyday Practical Electronics February 2009 PiCmicro TUTORIALS AND PROGRAMMING VERSION 3 PiCmicro MCU development board Suitable for use with the three software packages listed below This flexible development board allows students to learn both how to program PlCmicro microcontrollers as well as program a range of 8 18 28 and 40 pin devices from the 12 16 and 18 series PlCmicro ranges For experienced programmers all programming software is included in the PPP utility that comes with the development board For those who want to learn choose one or all of the packages below to use with the Development Board e Makes it easier to develop PlCmicro projects e Supports low cost Flash programmable PlCmicro devices Fully featured integrated displays 16 individual l e d s quad 7 segment display and alphanumeric l c d display Fully protected expansion bus for project work USB programmable ASSEMBLY FOR PiCmicro V3 Formerly PiCtutor Assembly for PlCmicro microcontrollers V3 0 previously known as PlCtutor by John Becker contains a complete course in programming the PIC16F84 PlCmicro microcontroller from Arizona Microchip It starts with fundamental concepts and extends up to complex programs including watchdog timers interrupts and sleep modes The CD makes use of the latest sim
46. less important ripple counters No background other than a basic knowledge of electronics is assumed and the more theoretical topics are explained from the beginning as also are many working practices The book concludes with an explanation of microprocessor techniques as applied to digital logic Order code 106 9 05 UNDERSTANDING ELECTRONIC CONTROL SYSTEMS Owen Bishop Owen Bishop has produced a concise readable text to introduce a wide range of students technicians and professionals to an important area of electronics Control is a highly mathematical subject but here maths is kept to a minimum with flow charts to illustrate principles and techniques instead of equations Cutting edge topics such as microcontrollers neural networks and fuzzy control are all here making this an ideal refresher course for those working in Industry Basic principles control algorithms and hardwired control systems are also fully covered so the resulting book is a comprehensive text and well suited to college courses or background reading for university students The text is supported by questions under the headings Keeping Up and Test Your Knowledge so that the reader can develop a sound understanding and the ability to apply the techniques they are learning Order code NE35 24 99 HOW ELECTRONIC THINGS WORK AND WHAT TO DO WHEN THEY DON T Robert Goodman You never again have to be flummoxed flustered or taken for a ride by a piece of el
47. making colours look slightly odd mind you so do sodium and mercury vapour street lights It was only recently that I discovered the green tinge had nothing to do with gas as a substance In fact today s natural gas light has the same green glow as the old town gas coal gas did and the greenish blue colour comes from the emission spectrum of thorium The mantles are made by soaking cotton bags in thorium and cerium nitrates and then drying them out In a world rightly obsessed with finding greener methods of lighting our homes offices factories and public buildings thorium may represent the answer Not because of its unnatural light spectrum but because thorium is mildly radioactive and a potential energy source In fact thorium may be a solution to our energy needs in the coming decades particularly because the energy stored in known reserves of thorium exceeds the total of all fossil fuels According to the World Nuclear Association a commercial organisation committed to sustainable development thorium is three times more abundant in nature than uranium and can be used as a nuclear fuel through breeding to uranium 233 U 233 When this thorium fuel cycle is used much less plutonium and other transuranic elements are produced compared with uranium fuel cycles Several reactor concepts based on thorium fuel cycles are under consideration notably by Russia which has had a programme to develop a thorium uranium fue
48. many other attractive accessories may also be fitted This in essence is case modding or PC Customising as it is sometimes called and this book provides all the practical details you need for using the main types of case modding components including Electro luminescent EL go faster stripes Internal lighting units Fancy EL panels Data cables with built in lighting Data cables that glow with the aid of black light from an ultraviolet UV tube Digital display panels LED case and heatsink fans Coloured power supply covers 192 pages CD ROM 6244111077 8 99 ROBOT BUILDERS COOKBOOK Owen Bishop This is a project book and guide for anyone who wants to build and design robots that work first time With this book you can get up and running quickly building fun and intriguing robots from step by step instructions Through hands on project work Owen introduces the programming electronics and mechanics involved in practical robot design and build The use of the PIC microcontroller throughout provides a painless introduction to programming harnessing the power of a highly popular microcontroller used by students hobbyists and design engineers worldwide Ideal for first time robot builders advanced builders wanting to know more about programming robots and students tackling microcontroller based practical work and labs The book s companion website at http books elsevier com companions 9780750665568 contains
49. not going to be expected to keep track of when your IP address changes Virtual Server 824486 124 E UN 10000 o Fig 2 A typical router NAT setup screen Solutions Fortunately there is a free reliable service that solves both these problems DynDNS is a service on the Internet that allows you to register your Public IP address and select a unique domain name that can be used to refer to it This is how the author set up his demonstration website at http mikehibbett dyndns org When the IP address changes one simply contacts the DynDNS service provider with the new IP address assigned by the ISP and the global mapping of the dyndns org website is changed instantly The service is not only free it is so widely used that many routers provide a means to automatically contact the DynDNS service should your public IP address change You can find more details by going to the website at www dyndns com and clicking on Free Dynamic DNS Home Logout gt You can configure the DSL Cable Router as a virtual server so that remote users accessing services such as the Web or FIP at your local site via public IP addresses can be automatically redirected to local servers configured with private IP addresses In other words depending on the requested service TCP UDP port numbers the DSL Cable Router redirects the external service request to the appropriate server located at another i
50. potential should be reduced to match the coil voltage if a 5V or 6V relay is used The coil resistance should be about 180 2 or greater Easy does It There are numerous integrated circuits designed to provide RS232C line drivers and or receivers and the 202 is one of the easiest to use It contains two line receivers plus a couple of line drivers and the power supply circuitry to enable the drivers to operate at the correct output voltages even though the MAX202 operates from a single 5V supply Fig 4 shows the circuit for twin line drivers and receivers based on the MAX202 In the present context it is only the line drivers that are of interest but in many practical applications it is necessary for the peripheral device to send data or handshake signals back to the computer The line drivers can then be used to provide the proper signal levels needed to drive RS232C inputs reliably An advantage of using the MAX202 is that it provides dual 12V supplies for the line drivers without the need for any Fig 3 A simple relay driver circuit that can be controlled using an RS232C handshake output Everyday Practical Electronics February 2009 expensive or awkward components such as high quality inductors for low frequency operation Capacitors C2 to C4 are the only discrete components needed for the supply circuit and these must be high quality types such as tantalum capacitors Remember it is the convention for line
51. solution Essentially we have a high speed oscillator running at 5MHz and this frequency is counted and then cap tured for the period between firing pulses For a 40Hz input we would have 40 firing pulses every second and the counter would count up to 125 000 5 000 000 40 between pulses The value of 125 000 may not appear to be of much use but if we divide this number into 150 million we get the correct 1200 RPM reading for a 4 cyl inder 4 stroke engine The resolution is now one RPM We can use a different numerator for the division calculation for each type of engine For example fora twin cylinder 4 stroke engine we use a value of 300 million for the numerator In this case a 40Hz signal would give a reading of 2400 RPM The RPM calculations are repeated every 1ms and a new RPM reading will be obtained ifthe captured count value is different from the previous count The actual rate at which the RPM is updated is dependent on the time pe riod between the firing pulses For the 40Hz signal we have an RPM update 40 times per second or once every 25ms This is 12 times faster than the RPM measurement described in Fig 1 At higher RPM the update time is even quicker With a 100Hz signal equivalent to 3000 RPM for a 4 cylinder 4 stroke engine the 11 Constructional Maingkeatunes Fast 32 LED circular bargraph Dot or bargraph option 4 digit display Gear shift indicator LED Limiter signal output Display f
52. the current amplifi cation provided by the bomb proof Zetex ZTX653 transistor 2A continuous at IW Although the output curve gave a good fit especially in the all important lower half of the fuel range the voltage needed shift ing up by about a volt This was accomplished by introducing a couple of diodes in the feedback loop one silicon 1N4148 and one Schottky BAT85 Added together their forward voltage drops give about 0 95 V helped by some forward biasing current through resistor R2 Setting up is quite simple adjust preset VR2 to give 10 output from IC2 and tweak preset VRI to set zero on the gauge Some might raise the question why no anti slosh conditioning 46 Ingenuity Uniimited Our regular round up of readers own circuits TR1 ZTX653 D1 D2 1N4148 85 k Fig 1 Circuit diagram for the Fuel Guage Interface to prevent the needle swinging around as the car flies over the bumps and the fuel sloshes around in the tank This is solved by the meter technology The fuel gauge needle is pivoted on a bimetallic arm Wire coiled around the arm heats it according to the voltage applied to the gauge Due to the differing expansion rates of the two metals the arm bends in proportion to the temperature change caused by the current in the wires and the needle moves across the scale The thermal inertia of this system eliminates rapid changes in needle posit
53. tool to help debug your PIC software PIC Video Cleaner Improving video viewing on poorly maintained TVs and VCRs PIC Graphics LCD Scope A PIC and graphics LCD signal monitor for your workshop PIC to Printer Interface How to use dot matrix printers as data loggers with PIC microcontrollers PIC Polywhatsit A novel compendium of musical effects to delight the creative musician PIC Magick Musick Conjure music from thin air at the mere untouching gesture of a fingertip PIC Mini Enigma Share encrypted messages with your friends true spymaster entertainment PIC Virus Zapper Can disease be cured electronically Investigate this controversial subject for yourself PIC Controlled Intruder Alarm A sophisticated multi zone intruder detection system that offers a variety of monitoring facilities PIC Big Digit Display Control the giant ex British Rail platform clock 7 segment digits that are now available on the surplus market PIC Freezer Alarm How to prevent your food from defrosting unexpectedly PIC World Clock Graphically displays world calendar clock and global time zone data PICAXE Projects A 3 part series E PICAXE devices PIC microcontrollers that do not need specialist knowledge programming equipment PIC based Tuning Fork and Metronome by at long last getting your instrument properly tunea Versatile PIC Flasher An attractive display to enhance your Christmas decorations or your child
54. wires amp matrix board PCB Production Drafting Materials A4 Artwork Film per 10 sheets Clear Manual Film 1 20 Clear Laser Film _ 175 White H Laser Film 4 62 Etch Resist Pens Dalo Pen 5210 Staedtler Fine 1 20 Etch Resist Transfers 2210 mixed DIL ee a eno mixed Rnd pads 2 Alfac mixed pads 1 84 Transfer Spatular 125 We carry the full of Seno amp Alfac PCB transfers see our web site for full details Soldering Irons We carry in stock a wide range of nd en and soldering accessories Irons from 12 to 100 Watts 25W 240V Ceramic 6 00 30W 240V Basic 4 68 Sage Desolder Pumps Basic 165 x 18 2 85 Antistatic 195mm 4 12 Antex Mini 198mm 6 52 Antex Pro 210mm 11 11 Soldering Station A 48W adjustable temperature station with a rotary di al LED Temperature metering on off switch iron holder and tip clean ing sponge This station features ac curate heat das for instant compensation amp stable tempera tures temperature range of 150 420 C Low volt age iron with Silicone cable Supply 240V Iron 24V 48W Model 167 540 49 00 Soldering Station 48W adjustable temperature soldering station with a rotary di al Pigil Temperature Indication on off switch iron holder and tip ge cleaning sponge This station fea tures accurate heat instant compens
55. 0 silicone washer and a nylon screw the PC board for any shorts between copper tracks or open circuits and make any necessary repairs You can now begin the assembly by installing the 1100 resistor R1 and the three diodes making sure the latter are all oriented correctly the banded ends are the cathodes K That done capacitors C1 to C3 can be installed again taking care with their orientation since they are all electrolytic types Next install PC stakes for the IN OUT and GND terminals then install trimpot VR1 Regulator REG1 can also be mounted It can either be mounted on the top of the PC board as shown in the photo or under neath as shown in Fig 3 so that it can be fastened to a heatsink Heatsinking Whether or not you need a heatsink for REG1 depends on the output cur rent and the voltage between the IN and OUT terminals of the regulator Everyday Practical Electronics February 2009 That s because these two values togeth er determine the power dissipation within the regulator It s determined simply by multiplying the two values together to get the power dissipation in watts ie P VI Generally if the dissipation is less than 0 25W no heatsink will be required For example if the current drawn from the regulator is 50mA and the voltage between the IN and OUT terminals is 5V then the dissipation will be 0 25W and no heatsink will be necessary However if the dissipation is more th
56. 00KT 59 95 ost items are available in kit form KT suffix r assembled and ready for use AS prefix Motor Speed Controllers Here are just a few of our controller and driver modules for AC DC Unipolar Bipolar stepper motors and servo motors See website for full details DC Motor Speed Controller 100V 7 5A Control the speed of almost any common DC motor rated up to 100V 7 5A Pulse width modulation output for maximum motor torque at all speeds Supply 5 15Vdc Box supplied Dimensions mm 60Wx100Lx60H Kit Order Code 3067KT 13 95 Assembled Order Code AS3067 21 95 PC Standalone Unipolar Stepper Motor Driver Drives any 5 6 or 8 lead unipolar stepper motor rated up to 6 Amps max Provides speed and direc tion control Operates in stand alone or PC controlled mode Up to six 3179 driver boards can be connected to a single parallel port Supply 9Vdc PCB 80x50mm Kit Order Code 3179KT 12 95 Assembled Order Code AS3179 19 95 Bi Polar Stepper Motor Driver Drive any bi polar stepper motor using externally sup plied levels for stepping and direction control These usually come from software running on a computer Supply 8 30Vdc PCB 75x85mm Kit Order Code 3158KT 17 95 Assembled Order Code AS3158 27 95 Bidirectional DC Motor Controller Controls the speed of most common DC motors rated up to 32Vdc 10A in both the forward and re verse
57. 02 874562 Email epeads wimborne co uk For rates and information on display and classified advertising please contact our Advertisement Manager Stewart Kearn as above BTEC ELECTRONICS TECHNICIAN TRAINING NATIONAL ELECTRONICS VCE ADVANCED ICT HNC AND HND ELECTRONICS FOUNDATION DEGREES NVQ ENGINEERING AND IT DESIGN AND TECHNOLOGY LONDON ELECTRONICS COLLEGE 20 PENYWERN ROAD EARLS COURT LONDON SW5 9SU TEL 020 7373 8721 www lec org uk Coastronix For a wide range of electrical goods from LEDS PICS soldering equipment Versatile Programmable PIC On Screen Display lay text over an signal Fuly amp O for se e PIC 16FG284 micro User definable fonts Example code for MSF cash register wire BARDWELL Ltd est 1948 Electronic Component Supplies LED s Semis IC s Resistors Caps etc 1000 s bargains at our secure site www bardwells co uk 288 Abbeydale Rd Sheffield 57 1FL 0845 166 2329 local rate or interfaces and much more take a look at www coastronix com or call 01634 660157 The British Amateur Electronics Club Archive Website Archiving extracts for 140 Newsletters from 1966 2002 Currently have interesting and useful selected articles from 19 Newsletters Also a section about built electronics projects with schematics and photos Plus useful info downloads and links NO ADVERTS Website Address http baec tripo
58. 150mAh Instrument case with edge connector and screw terminals Size 112mm x 52mm x 105mm tall This box consists of a cream base with a PCB slot a cover plate to pro tect your circuit a black lid with a 12 way edge connector and 12 screw terminals built in 8mm pitch and 2 screws to hold the lid on The cream bases have minor marks from dust and handling price 2 00 VAT 2 2 35 for a sample or 44 00 VAT 51 70 for a box of 44 866 battery pack originally intended to be used with an orbitel mobile telephone it contains 10 1 6Ah sub C batteries 42 x 22 dia the size usually used in cordless screwdrivers etc the pack is new and unused and can be broken open quite easily 7 46 VAT 8 77 Please add 1 66 VAT 1 95 postage amp packing per order JPG Electronics Shaws Row Old Road Chesterfield S40 2RB Tel 01246 211202 Fax 01246 550959 www JPGElectronics com Mastercard Visa Switch Callers welcome 9 30 a m to 5 30 p m Monday to Saturday ELECTRONICS NEXT MONTH VU PEAK METER WITH LCD BARGRAPHS There are VU meters and then there s our VU meter This audio essential is a sophisticated but easy to build bargraph display that makes it simple to record audio signals at the correct level It shows both the average signal and peak levels in stereo on an LCD and you can adjust both the display range and number of steps It s just the thing for all you budding audiophiles and DIY sound engineers WATER TAN
59. 2 168 62 62 2 168 62 62 255 255 255 255 4 8 1 127 0 0 1 255 255 255 255 62 62 62 62 240 0 0 6 62 62 62 62 255 255 255 255 255 255 255 255 192 168 62 1 to in this case the modem is a combined modem router Other modems have a single Ethernet connection that connects to a stand alone router to which your PC connects If you re terribly modern then your modem or router is equipped with a WiFi interface an Access Point to which your laptop computer can connect wire lessly If you are very unlucky then your modem is equipped with a USB connection which plugs straight into your laptop If this is the case then you should skip the rest of these 127 0 0 6 169 254 0 6 192 168 62 0 192 168 62 62 192 168 62 255 224 0 0 6 255 255 255 255 255 255 255 255 Default Gateway Fig 1 A PC s IP and route setup 58 Everyday Practical Electronics February 2009 CINeXa System WAN LAN NAT b Special Application Virtual Server Firewall web a webserver to which you can attach and make configuration changes Typing the IP address of the router into your web browser is the normal way to gain access to the router s configuration pages Security One very important task that a router will perform is to stop people remotely accessing your network Most will do this by default if they didn t then your computer would quickly become infected with viruses But we want people to be able to connect into o
60. 20 x 8 pin DIL sockets SP103 15 x 14 pin DIL sockets SP104 15 x 16 pin DIL sockets SP109 15 x BC557B transistors SP112 4 x CMOS 4093 SP115 3 x 10mm Red LEDs SP116 3 x 10mm Green LEDs SP118 2 x CMOS 4047 SP124 20 x Assorted ceramic disc caps SP130 100 x Mixed 0 5W C F resistors 2 x TLO71 Op Amps 20 x 1N4004 diodes 15 x 1N4007 diodes 5 x Miniature slide switches 3 x BFY50 transistors SP137 SP138 SP142 SP143 4 x W005 1 5A bridge rectifiers 20 x 2 2 63V radial elect caps 2 x CMOS 4017 5 Pairs min crocodile clips Red amp Black 5 Pairs min crocodile clips assorted colours 10 x 2N3704 transistors 5 x Stripboard 9 strips x 25 holes 4 x 8mm Red LEDs 4 x 8mm Green LEDs 4 x 8mm Yellow LEDs 15 x BC548B transistors 3 x Stripboard 14 strips x 27 holes 10 x 2N3904 transistors 10 x 2N3906 transistors 2 x C106D thyristors 2 x LF351 Op Amps 20 x 1N4003 diodes 5 x BC107 transistors 5 x BC108 transistors 4 x Standard slide switches 10 x 220 25V radial elect caps 20 x 22 25V radial elect caps 20 x 1 63V radial elect caps 10 x 1A 20mm quick blow fuses 10 x 2A 20mm quick blow fuses 5 x Phono plugs asstd colours 20 x 4 7 63V radial elect caps 20 x BC547B transistors 8 x 1M horizontal trimpots 4 x 5 metres solid core wire 3 x CMOS 4066 3 x 10mm Yellow LEDs 6 x 20 pin DIL sockets 5 x 24 pin DIL sockets 5 x 25mm mono jack plugs 5 x 2 5mm mono jack sockets SP144 SP146 SP147 SP151 SP152 SP153 SP154 SP156 S
61. 41 s output voltage does not fall to zero as required to disable the alarm when the temperature is above 0 C e If you want a simpler circuit you could dispense with IC3 and its associ ated components and then use the flash ing LED as your alarm function Alterna tively you could reduce the value of C1 to 100nF to produce a continuous alarm Everyday Practical Electronics February 2009 tone in which case LED1 would flash at too high a frequency to be of use e The circuit could be set up to sound the alarm at a different temperature from 0 C depending on the setting of VR1 Protobloc component layout minus speaker and battery 49 Breadboarding Project 10 Simple Dice E circuit diagram shown in Fig 5 3 makes an interesting electronic alternative to the traditional little cubic dice with its collection of dots on its six faces The circuit is based on a CMOS 4017 decade counter IC2 which has ten outputs that go high positive in turn with each successive clock pulse pro duced by a 555 timer IC1 operating as an astable This is achieved by connecting output pin 3 of the 555 to the clock input pin 14 of the 4017 However instead of allowing the 4017 to cycle through all of its ten states the reset pin 15 is connected to the Q6 output pin 5 so that the 4017 only cycles through states QO to Q5 resetting to QO as pin 5 goes high When each of the six outputs QO to Q5 goes high
62. 5 plus postage amp packing This kit operates a relay when a preset temperature is exceeded and drops out the relay when temperature drops Ideal as a thermostat ice alarm or hydroponics applications etc Adjustable temperature range of approx 30 to 150 C Kit includes NTC thermocouple 12VDC required e Kit includes 20W halogen lamp PCB plus electronic components e Now includes ceramic base FREE CATALOGUE Checkout Jaycar s extensive range HOW TO ORDER e ORDER ON LINE www jaycarelectronics co uk e PHONE 0800 032 7241 e FAX 61 2 8832 3118 e EMAIL techstore jaycarelectronics co uk e POST Box 107 Rydalmere NSW 2116 Australia e ALL PRICING IN POUNDS STERLING e MINIMUM ORDER ONLY 10 Australian Eastern Standard Time Monday Friday 09 00 to 17 30 GMT 10 hours only Expect 10 14 days for air parcel delivery For your FREE catalogue log on to www jaycarelectronics co uk catalogue or check out the range at www jaycarelectronics co uk ms lectronics PCB Production Development 0 1 Copper Stripboard Size Tracks Holes 25 x 64mm 75 64 x 95mm 95 127mm 36T 50H 95 x 432mm 36T 170H 100 x 100mm 39T 38H 100 x 500mm 39T 199H 119 455mm 46T 179H Stripboard track cutter Solderless Breadboard Tie Points amp Size Paner Pails 3 32 175 42 0 3 08 Many other sizes available i also jump
63. A VIDED GAME CONSOLE Design inspired fy the Atari 80072600 X Spectrum Apple 11 amp Cammodore 64 Complete Package eBook 1 Great for Hobbyists AND Camplete Sariwa Ki eBook on Deslgning the AGS Console Parallax S2 Key Compatible Fully EET ui 65 Micro Edition Unit J BU Fun Way to Learn Embodded Systems F a E zm d Mm s pr P9 4 E y WWW XGAM ES TATION co 312 266 2390 37 Mach Glen drum sounds Us SOMA Computerjor SHG Itolseven instruments atfone time TEAGHEIN RIC microcontr Programme E Ao uj y ee 70 Wome pss AKIS to youripl VOL 1 BACK ISSUES January 1999 to June 1999 Plus some bonus material from Nov and Dec 1998 VOL 2 BACK ISSUES July 1999 to December 1999 VOL 3 BACK ISSUES January 2000 to June 2000 VOL 4 BACK ISSUES July 2000 to December 2000 VOL 5 BACK ISSUES January 2001 to June 2001 VOL 6 BACK ISSUES July 2001 to December 2001 VOL 7 BACK ISSUES January 2002 to June 2002 VOL 8 BACK ISSUES July 2002 to December 2002 VOL 9 BACK ISSUES January 2008 to June 2003 VOL 10 BACK ISSUES July 2003 to December 2003 VOL 11 BACK ISSUES January 2004 to June 2004 VOL 12 BACK ISSUES July 2004 to December 2004 VOL 13 BACK ISSUES January 2005 to June 2005 VOL 14 BACK I
64. A closer look at the characteristics in Fig 6 for low gate source voltages approximate graph Fig 8 Parallel BJTs need emitter resistors to help reduce current hogging and thermal runaway problems MOSFETs generally do not suffer from this problem its current to increase so it gets hotter still and so on a process known as thermal runaway which may lead to destruction of the transistor The problem can be reduced by including a resistor in the emitter circuit of each transistor chosen to give around 0 2V drop at full load current see Fig 8 References Fairchild Semiconductor BS170 MMBFI70 N Channel Enhancement Mode Field Effect Transistor 1995 Datasheet www fairchildsemi com ds BS BS170 pdf Alfio Consoli et al Thermal Instability of Low Voltage Power MOSFETs IEEE Transactions on Power Electronics Vol 15 No 3 May 2000 pp 575 581 Alan Ball Thermal Stability MOSFETs ON Semiconductor Application Note AND8199 2005 www onsemi com pub link Collateral AND 8199 D PDF INFO FERYSTER EU Everyday Practical Electronics February 2009 Everyday Practical Electronics February 2009 Radio The leading magazine for vintage radio YYLONES enthusiasts April May 2008 3 75 E Russian Cold War Spy Sets And Encoders e Issue No 112 2008 arch 1 Radio P 0 ly 200 aa Ssue No Fr H t Bygones 1 115
65. AT UK and EU customers add VAT at 1596 to plus VAT prices 61 Everyday Practical Electronics February 2009 SPECIAL PACKAGE OFFER DIGITAL WORKS TINA Pro V7 Basic Flowcode V3 Hobbyist Student TINA Analogue Digital Symbolic RF MCU and Mixed Mode Circuit Simulation Testing and PCB Design TINA Design Suite is a powerful yet affordable software package for analysing designing and real time testing analogue digital MCU and mixed electronic circuits and their PCB layouts You can also analyse communication optoelectronic circuits test and debug microcontroller applications Enter any circuit up to 100 nodes within minutes with TINAS easy to use schematic editor Enhance your schematics by adding text and graphics Choose components from the large library containing more than 10 000 manufacturer models Analyse your circuit through more than 20 different analysis modes or with 10 high tech virtual Counter project instruments Present your results in TINA s sophisticated diagram windows on virtual instruments or in the live interactive mode where you can even edit your circuit during operation Digital Works Version 3 0 is a graphical design tool that enables you to construct Customise presentations using TINA s advanced drawing tools to control text fonts axes line width colour and layout You can create digital logic circuits and analyze their and print documents directly inside TINA or cut and paste your results
66. Australia and Papua New Guinea which cost 10 50 Normally sent within seven days but please allow 28 days for delivery more for overseas Payment in sterling only please Visa Maestro and MasterCard accepted Send fax or phone your card number card expiry date valid from date and card security code the last 3 digits on or just under the signature strip with your name address etc Or order on our secure server via our UK website Overseas customers your credit card will be charged by the card provider in your local currency at the existing exchange rate Everyday Practical Electronics February 2009 VOL 38 No 2 FEBRUARY 2009 Editor MATT PULZER Consulting Editors DAVID BARRINGTON JOHN BECKER Subscriptions MARILYN GOLDBERG General Manager FAY KEARN Editorial Admin 01202 873872 Advertising and Business Manager STEWART KEARN 01202 873872 On line Editor ALAN WINSTANLEY EPE Online Internet version Editors CLIVE Max MAXFIELD and ALVIN BROWN Publisher MIKE KENWARD READERS TECHNICAL ENQUIRIES Email techdept epemag wimborne co uk We are unable to offer any advice on the use purchase repair or modification of commercial equipment or the incorporation or modification of designs published in the magazine We regret that we cannot provide data or answer queries on articles or projects that are more than five years old Letters requiring a personal reply must be accompanied by a stamped self addressed
67. C board code 699 size 117 x 101mm 1 PC board code 700 89mm diameter Both circiut boards available from the EPE PCB Service 1 small instrument case size 140 x 110 x 35mm 1 ORP12 type light dependent resistor LDR1 1 20MHz parallel resonant crystal X1 1 right angle 10 pin IDC header 1 10 way IDC line socket 1 10 way IDC PC board transition connector 1 3 way pin header 1 jumper shunt for 3 way header 2 2 way PC board mount screw terminals 5 08mm pin spacing 1 powdered iron core 28mm OD x 14mm ID x 11mm Jaycar LO 1244 L1 1 TO220 heatsink 25 x 29 5 x 12 6mm 3 SPST micro tactile switches vertical mount 0 7mm actuator 51 to 53 2 50mm cable ties 1 18 pin DIL IC socket 1 500mm length of 0 7mm tinned copper wire 1 1m length of 10 way IDC cable 1 3 5m length of 0 5mm enamelled copper wire 2 M3 x 10mm screws 4 M3 x 6mm screws 2 M3 nuts 2 PC stakes Extra hardware for Display 3 M3 brass nuts 6 M3 x 12mm Nylon screws 6 M3 Nylon nuts 3 M3 x 12mm countersink screws resistor in series with trimpot VR1 The feedback voltage at pin 5 is maintained at 1 25V for regulation of the output It means that with the addition of the resistive divider the output voltage can be higher than 1 25V VR1 allows adjust ment of the output from 1 8V up to 4V The incoming 12V supply from the car s battery is fed via diode D1 which provides protection against reversed polarity and the supply is filtered with th
68. CS WITH LEGO MINDSTORMS Robert Penfold Shows the reader how to extendthecapabilities of the brilliant Lego Mindstorms Robotic Invention System RIS by using lego s own accessories and some simple home constructed units You will be able to build robots that can provide you with waiter service when you clap your hands perform tricks see and 264 pages avoid objects by using bats radar or accurately follow a line marked on the floor Learn to use additional types of sensors including rotation light temperature sound and ultrasonic and also explore the possibilities provided by using an additional third motor For the less experienced RCX code programs accompany most of the featured robots However the more adventurous reader is also shown how to write programs using Microsoft s VisualBASIC running with the ActiveX control Spirit OCX that is provided with the RIS kit Detailed building instructions are provided for the featured robots including numerous step by step photographs The designs include rover vehicles a virtual pet a robot arm an intelligent sweet dispenser and a colour conscious robot that will try to grab objects of a specific colour 902 14 99 THE PIC MICROCONTROLLER YOUR PERSONAL INTRODUCTORY COURSE THIRD EDITION John Morton Discover the potential of the PIC microcontroller through graded projects this book could revolutionise your electronic
69. EP 10 Slip a 120mm length of 10mm diameter heatshrink tubing over this twisted pair and lightly shrink it into place using a hot air gun gently does it STEP 11 Secure this section of the cable in position using another two nylon P clamps As before these should be orientated exactly as shown in Fig 1 STEP 12 Trim the brown cable to length and crimp on a female spade connector STEP 13 Plug the connectors into the IEC socket The blue lead goes to the neutral terminal while the brown lead goes to Live STEP 14 Further secure the leads using cable ties two between the transformer and the first P clamp and one right at the IEC socket STEP 15 Prepare a 100mm long earth lead with female spade connectors at either end and connect it between the earth terminal on the IEC socket and a spare chassis earth lug STEP 16 Fit a 4A slow blow fuse to the IEC socket STEP 17 Secure all the wiring in the amplifier by fitting cable ties as shown in Fig 1 This not only improves the appearance by keeping everything tidy but ensures reliability as well In particular make sure that the 230V mains wiring is properly se cured by the P clamps and by fitting cable ties immediately behind the spade connectors at the IEC socket and the mains switch Initial checks That completes the wiring but there are a few things to check before plugging in a mains cable and switch ing on Just follow this step by step checklist 1
70. G ELECTRONICS THIRD EDITION KEITH BRINDLEY A punchy practical introduction to self build electronics The ideal starting point for home experimenters technicians and students who want to develop the real hands on skills of electronics construction A highly practical introduction for hobbyists students and technicians Keith Brindley introduces readers to the functions of the main component types their uses and the basic principles of building and designing electronic circuits Breadboarding layouts make this very much a ready to run book for the experimenter and the use of multimeter but not oscilloscopes and readily available inexpensive components makes the practical work achievable in a home or school setting as well as a fully equiped lab Order code 42 12 99 VIDEO PROJECTS FOR THE ELECTRONICS CONSTRUCTOR R A Penfold Written by highly respected author R A Penfold this book contains a collection of electronic projects specially designed for video enthusiasts All the projects can be simply constructed and most are suitable for the newcomer to project construction as they are assembled on stripboard There are faders wipers and effects units which will add sparkle and originality to your video recordings an audio mixer and noise reducer to enhance your soundtracks and a basic computer control interface Also there s a useful selection on basic video production techniques to get you started Circuits include
71. ICON CHIP magazine 2009 www siliconchip com au Laser 3B by www laser com Back issues are also available 42 Integrators Installers Trade and Retail customers welcome KATS AV transmission and IR control system Barix Ethernet based communications ey C Bus Shop C Bus and C Bus Wireless www cbus shop com Laser Business Systems Ltd Tel 44 0 20 8441 9788 Fax 44 0 20 8449 0430 Email info laser com 16 Garthland Drive ENS 3688 Everyday Practical Electronics February 2009 ELECTRONICS MANUALS ON CD ROM 29 95 EACH ELECTRONICS SERVICE MANUAL ELECTRONICS SERVICE MAHUAL A practical reference ma ees oom electronics Servicing N z aub ee E TE Everything you need to know to get started in repairing electronic equipment 9 Around 900 pages 9 Fundamental principles Troubleshooting techniques 9 Servicing techniques Choosing and using test equipment 9 Reference data Manufacturers web links 9 Easy to use Adobe Acrobat format 9 Clear and simple layout 9 Vital safety precautions 9 Professionally written Supplements SAFETY Safety Regulations Electrical Safety and First Aid UNDERPINNING KNOWLEDGE Electrical and Electronic Principles Active and Passive Components Circuit Diagrams Circuit Measurements Radio Computers Valves and manufacturers
72. K LEVEL INDICATOR Water rates up metering round the corner hosepipe bans eco friendly water usage there are many reasons to install your own water tank and make use of what falls freely from the sky However with a really large tank how do you know what the water level is The answer is a neat circuit from your favourite electronics magazine This elegant solution is perfect for the seasoned builder or the comparative novice there are no microcontrollers or fancy displays just good old fashioned ingenuity LED TACHOMETER PART 2 Following on from the introduction and assembly of the electronics for our state of the art tachometer Part 2 shows you how to house the meter and set it up for your selected engine type MARCH 09 ISSUE ON SALE FEB 12 ADVERTISERS INDEX AUDON ELECTRONICS BETA LAYOUT COMPACT CONTROL DESIGN CRICKLEWOOD DISPLAY ELECTRONICS ESR ELECTRONIC COMPONENTS FERYSTER JAYCAR ELECTRONICS JPG ELECTRONICS LABCENTER LASER BUSINESS SYSTEMS MAGENTA ELECTRONICS NURVE NETWORKS LLC PEAK ELECTRONIC DESIGN QUASAR ELECTRONICS SHERWOOD ELECTRONICS STEWART OF READING ADVERTISEMENT OFFICES Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU PHONE 01202 873872 Fax 01202 874562 EMAIL epeads wimborne co uk For Editorial address and numbers see page 4 Published on approximately the second Thursday of each month by Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown D
73. NLINE WWW PCB POOL COM Pre 2 oF GrophiGeas RI ISSN 0262 3617 PROJECTS THEORY NEWS COMMENT e POPULAR FEATURES 9 VOL 38 No 2 February 2009 Wimborne Publishing Ltd 2009 Copyright in all drawings photographs and articles published in EVERYDAY PRACTICAL ELECTRONICS is fully protected and reproduction or imitations in whole or in part are expressly forbidden Our March 2009 issue will be published on Thursday 12 February 2009 see page 72 for details Everyday Practical Electronics February 2009 INCORPORATING ELECTRONICS TODAY INTERNATIONAL WWW epemag com LED TACHOMETER PART 1 by John Clarke For use with virtually any internal combustion engine ADJUSTABLE 1 3V TO 22V REGULATED POWER SUPPLY by John Clarke Simple easy to build versatile circuit 20W CLASS A AMPLIFIER MODULE Pt 5 by Greg Swain Chassis assembly wiring and adjustment details INGENUITY UNLIMITED Sharing your ideas with others Fuel Gauge Interface BREADBOARDING PROJECTS by Dr Malcolm Plant Part 5 Frost Alert Simple Dice TECHNO TALK by Mark Nelson Unforgettable Memories RECYCLE IT by Julian Edgar A voltmeter for almost nothing RECYCLE IT by Julian Edgar Salvaging and using common thermostats INTERFACE by Robert Penfold More on serial port compatibility CIRCUIT SURGERY by lan Bell MOSFET physics and parallel transistors PIC N MIX by Mike Hibbe
74. P160 SP161 SP164 SP165 SP166 SP167 SP168 SP172 SP173 SP174 SP175 SP177 SP178 SP181 SP182 SP183 SP186 SP189 SP192 SP195 SP197 SP198 SP199 SP200 SP131 SP133 SP134 SP135 SP136 Catalogue available 1 inc P amp P or FREE with first order P amp P 1 75 per order NO VAT Cheques and Postal Orders to SHERWOOD ELECTRONICS 10 NEWSTEAD STREET MANSFIELD NOTTS NG19 6JJ RESISTOR PACKS C Film 5 each value total 365 0 25W 3 40 RP7 10 each value total 730 0 25W 4 65 RP10 1000 popular values 0 25W 6 60 4 5 each value total 305 0 5W 4 20 8 10 each value total 610 0 5W 6 85 RP11 1000 popular values 0 5W 8 95 CRICKLEWOOD ELECTRONICS Established 1981 Frustrated with your suppier Visit our component packed website for a vast range of parts old and new many unavailable elsewhere www cricklewoodelectronics com 1000 s OF PRICES REDUCED Alternatively phone us on 020 8452 0161 with your requirements Visit our Shop Call or Buy online at www cricklewoodelectronics com Visit our shop at 02 0 84152 6 40 42 Cricklewood Broadway London NW2 3ET 47 Breadboarding Breadboa 4 beginner s guide to simple solder free circuit prototyping Part 5 Frost Alert and Simple Dice This month in Part 5 we present a couple more interesting circuits for building on breadboard a Frost Alert and a Simple Dice Project 9 Frost Al
75. SSUES July 2005 to December 2005 VOL 15 BACK ISSUES January 2006 to June 2006 VOL 16 BACK ISSUES July 2006 to December 2006 VOL 17 BACK ISSUES January 2007 to June 2007 VOL 18 BACK ISSUES July 2007 to December 2007 VOL 19 BACK ISSUES January 2008 to June 2008 NEW FIVE YEAR CD ROM Jan 2003 to Dec 2007 NOTE These CD ROMs are suitable for use on any PC with a CD ROM drive They require Adobe Acrobat Reader available free from the Internet www adobe com acrobat WHAT IS INCLUDED All volumes include the EPE Online editorial content of every listed issue plus links to all the available PIC Project Codes for the PIC projects published in those issues Please note that we are unable to answer technical queries or provide data on articles that are more than five years old Please also ensure that all components are still available before commencing construction of a project from a back issue Everyday Practical Electronics February 2009 iJ Aeae STA plateland f j F i Showsfsensor patchland volume sf Save my 422 One DG gt Di Of FF TVs a Ma VIS Br y of E SO ua Volume Numbers STORE YOUR BACK ISSUES ON CD ROMS Er pa QUU E A great way to buy EPE Back Issues our CD ROMs contain back issues from our EPE Online website plus bonus articles all the relevant PIC software links and web links Note no fre
76. TELEPHONE EQUIPMENT We advise readers that certain items of radio transmitting and telephone equipment which may be advertised in our pages cannot be legally used in the UK Readers should check the law before buying any transmitting or telephone equipment as a fine confiscation of equipment and or imprisonment can result from illegal use or ownership The laws vary from country to country readers should check local laws A roundup of the latest Everyday News from the world of electronics Freesat and Apricot Barry Fox reports on two product introductions one new and First Freesat recorder The first Freesat recorder the FOXS AT HDR from Humax is now on sale for 300 and Freesat is finally offering consumers advice albeit none too clear on what kind of dish they need to let a dual tuner recorder record one channel while watching another or record two channels Humax told Freesat soon after the May 08 service launch that it was essential to warn consumers of the need to install a dual LNB for future use of a recorder because Humax feared future calls from confused customers Freesat acknowledged in July 08 that there needs to be further information on installation etc so this is definitely something that is in development and will be improved upon over the next few weeks In early Oct 08 there was still no sign of advice Now there is advice in the Freesat website FAQ but it is st
77. THEN OMUKIMAGAZINEROR EVECTRONICSTECHNOLOGY eC OMPUTERIPROJEGTS P0 GUST X E TX ma S re Uy 4 7 m x X m i 1 m 8 75 US 10 25 CAN u 2009 PRINTEDIN THEUK e s f 7 6 Me 25274 07806 Copyright 2008 Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU UK and TechBites Interactive Inc PO Box 857 Madison Alabama 35758 USA All rights reserved WARNING The materials and works contained within EPE Online which are made available by Wimborne Publishing Ltd and TechBites Interactive Inc are copyrighted You are permitted to make a backup copy of the downloaded file and one 1 hard copy of such materials and works for your personal use International copyright laws however prohibit any further copying or reproduction of such materials and works or any republication of any kind TechBites Interactive Inc and Wimborne Publishing Ltd have used their best efforts in preparing these materials and works However TechBites Interactive Inc and Wimborne Publishing Ltd make no warranties of any kind expressed or implied with regard to the documentation or data contained herein and specifically disclaim without limitation any implied warranties of merchantability and fitness for a particular purpose Because of possible variances in the quality and condition of mate
78. a 4 cylinder 4 stroke engine there are two sparks or firing pulses per engine revolution A 40Hz pulse signal from the engine therefore corresponds to 1200 RPM 40 x 60 x 1 2 If we want the display to show 1200 we can do this in several ways First we can wait 30 seconds so that the counter reaches a count of 1200 but this is far too long to be practical A better method is to count the incoming signal over a 300ms period This would allow the counter to reach 12 after 300ms The display would Everyday Practical Electronics February 2009 then show a 12 and two more zeros could be added after the 12 to make it display 1200 These last two digits will always be set at zero and so the resolution is only 100 RPM The re sulting 300ms update time ie three times a second is probably fine for a digital display because we would not be able to read it if it changed at a much faster rate However if we add a multi LED bargraph to the tachometer then the 300ms update period would prevent the bargraph from rapidly responding to changes in engine revs a quick blip of the throttle would probably not even be registered The other problem with the 300ms update period is that it only has 100 RPM resolution and so the increments on the circular display would not be very precise Problem solved Clearly a tachometer with a bargraph that has many steps will need a much faster and more accurate means of measuring RPM Fig 2 is the
79. amp taxes may apply Prices valid until 28 2 09 Max weight 1216 5kg Heavier parcels POA Minimum order 10 REMOTE EXTENDER a MKII KIT KC 5432 25 plus postage amp packing Operate your DVD player or digital decoder using its remote control from another room It picks up the signal from the remote control and sends it via a 2 wire cable to an infrared LED located close to the device This improved model features fast data transfer capable of transmitting Foxtel digital remote control signals using the Pace 400 series decoder Kit supplied with case screen printed front panel PCB with overlay and all electronic components KG 9098 12 95 plus postage amp packing Using two a adj o motors that are fitted with mirrors patterns similar to a spirograph toy can be projected onto a wall Great for parties Operating voltage is W 6VDC PCB size 100 x 74mm Kit WE supplied with silk screened gold plated PCB 2 motors and mirrors plus all electronic components Don t forget to check out our laser Pointers and modules elsewhere in the catalogue Note Laser not included Requires 9VDC wall adaptor and 2 wire cable LUXEON STAR DRIVER KIT LT LLL SMS CONTROLLER 5389 75 plus MODULE KIT T amp packing Luxeon high power LEDs are some of the KC
80. amples In cludes a 16F627 Flash Microcontroller that can be reprogrammed up to 1000 times for experimenting at will Software to compile and program your source code is included Kit Order Code VK8048KT 22 95 Assembled Order Code VVM111 39 95 Controllers amp re data acquisition and control units we have See website for full details 12Vdc PSU for all units Order Code PSUA45 8 95 Here are just a few of the guo and USB Experiment Interface Board 5 digital input chan nels and 8 digital out put channels plus two analogue inputs and iz two analogue outputs ai with 8 bit resolution Kit Order Code VK8055KT 20 95 Assembled Order Code VVM110 39 95 Rolling Code 4 Channel UHF Remote State of the Art High security 4 channels Momentary or latching relay output Range up to 40m Up to 15 Tx s can be learnt by one Rx kit in cludes one Tx but more avail able separately 4 indicator LED s Rx PCB 7 7x85mm 12Vdc 6mA standby Two amp Ten Channel versions also available Kit Order Code 3180KT 44 95 Assembled Order Code AS3180 54 95 Computer Temperature Data Logger Serial port 4 channel tem perature logger C or F Continuously logs up to 4 separate sensors located 200m from board Wide range ot tree software applications for stor ing using data PCB just 45x45mm Powered by PC Includes one DS1820 sensor Kit Order Code 3145KT 17 95 Assembled Order Code AS3145
81. an this you will need to fasten the regulator to a heatsink to keep it cool For example let s say that the current drawn from regulator REG1 is 250mA and that the voltage across it is 5V In this case the dissipation will be 1 25W ie 5 x 0 25 and a heatsink will be necessary Heatsink temperature The type of heatsink required depends on the amount of power dissipated by the regulator and the temperature rise that can be tolerated Typically a 20 C rise in heatsink tem perature is acceptable because this means that at a typical room tempera ture of say 25 C the heatsink will run at 45 C which is quite tolerable Most heatsinks are specified by their temperature rise in C per watt C W This means that a 10 C W heatsink will rise 20 C above am bient when dissipating 2W Note that the LM317T TO 220 pack age is rated at 15W maximum power dissipation Isolation Usually it will be necessary to electri cally isolate the tab of the regulator from the heatsink see Fig 3 The reason for this is that the heatsink may be connect ed to ground 0V while the regulator metal tab sits at the output voltage To isolate the tab use a TO 220 silicone insulating washer and secure the assembly to the heatsink using an M3 nylon screw and nut Alternatively you can use a metal screw provided you fit an insulating bush into the regulator tab fixing hole Note that capacitor C1 may need to be increased in value if
82. anding over a handling fee It s known as the 419 scam because many of the missives come from Nigeria where Section 419 of the Penal Codes makes them illegal A new book Conned by James Morton and Hilary Bateson reveals that greedy gullibles have been falling for the same trick for over a hundred years In 1905 a prisoner in a Spanish jail was mailing letters asking for cash to retrieve impounded luggage which contained details of a secret bank account in Britain In China 419 scammers can expect the death penalty in the US there is a little known provision for claiming tax relief on money lost to scammers The book also tells how a Brit gets his revenge by asking any scammers who contact him to prove their identity by emailing back a photo of themselves holding a fish while balancing a loaf of bread on their head and with a sign round their neck saying plonker Barry Fox 9 Constructional Part 1 By JOHN A responsive and accurate tachometer is essential for motoring enthusiasts This unit features a bright 4 digit display plus a 32 LED circular bargraph The LED bargraph responds rapidly to changes in RPM while the digital display shows accurate RPM readings with a steady throttle IGITAL tachometers might be accurate but they don t respond like an analogue instrument This ta chometer combines the best features of analogue and digital instruments blip the throttle and the LED bargraph rapidl
83. ar A colleague presented the author with an ancient Smiths analogue fuel meter and asked if I could work out how to drive it The input is from a fuel sender basically a float on a swinging arm in the fuel tank offering a variable resistance output depen dent on the height of the fuel in the tank This is achieved by a short ing contact attached to the arm moving across a resistive track Measurements of the two components suggested that the tank re sistance was fairly linear over the fuel level range 3002 empty to 300Q full and the gauge had a resistance of 600 needing 2 5V to read Empty and 7 5V to read Full This confirmed that the obvious solution of putting the sender and gauge in series and running them off the vehicle supply wouldn t work the sender resistance went in the wrong direction Driving the sender with a constant current was also rejected and a PIC solution seemed too elegant Using Excel modelling on the computer it was found that a resistor in line driven from a regulated voltage would give an acceptably useful output and one of 300 driven by 10V would be about right This voltage swing required some buffering to drive the gauge over 100mA would be required at the upper end of the scale A power audio op amp was considered but with some voltages close to supply and ground it was decided to stick to a simple rail to rail CMOS 7621 wired in a voltage follower configuration with
84. ar phone mentioned it may be sold under another brand elsewhere so a little googling will help pinpoint the name the HTC Tytn II is also known as Kaiser AT amp T Tilt and P4550 There is plenty online for Apple iPhone owners to check out too Ee aee me am da 66 po he OE Boke Dee Uo goer m omm zac mec uo Dom The HTC Il discontinued is typical of PDA mobile phones using Windows Mobile to handle mail web and satellite navigation on the move Not so mobile email Having fallen for the seductive appeals of the Tytn II in practice although I could fetch POP3 email happily I had never managed to send a single email on the move and I gave up after a month or two Orange did eventually claim that their SMTP server had been down for months and this strange admission would explain why outbound mail was apparently broken However by scouring the forums I learned of a bug with Windows Mobile 6 1 that disabled the sending of mail if an SMTP server becomes unreachable eg smtp orange net then WM 6 1 would cripple the phone s account setup Eventually I learned of a forthcoming Microsoft patch but this is nothing that Orange knew about or would admit to at the time An update wa
85. assis to the left of the preamp board This is a single ended lug and is used to ensure a reliable earth connection for the body of the volume potentiometer Installing the modules The five PC board modules can now be installed in the chassis Note 28 that these modules are all mounted on 10mm tapped stand offs except for the preamplifier module which mounts on three 25mm tapped stand offs Begin by mounting the left and right channel power amplifier modules These should already be attached to their heatsinks and it s just a matter of lining these up with their mount ing holes in the chassis and bolting them into position using M4 x 10mm machine screws and star washers The star washers go under the heads of the screws and bite into the chassis to ensure that the heatsinks are securely earthed Note do not over tighten these screws The heatsinks are made of aluminium and it s all too easy to strip the threads if you are ham fisted Once the heatsink screws are in the spacers fitted to the power amplifier boards can be secured to the chas sis using M3 x 6mm screws and flat washers If necessary loosen off the heatsink screws under the chassis to get everything to line up then do the screws up nice and tight Preamplifier module The preamplifier module can now be mounted As previously mentioned the preamplifier is secured using only three of its four mounting holes the hole adjacent to the volume control
86. ata bits The receiving device is given an appropriate time to read the first bit after which the clock line is set low and then the data line is also set low Next the data line is set to the appropriate state for the second bit and then a low to high transition on the clock line is used to indicate to the receiving device that a fresh bit of data is available This sequence of events is repeated for the remaining six bits In Fig 5 a low to high transition is used to latch each bit of data into the receiving device but the system will work just as well if a transition in the opposite direction is used The crucial elements are to always have the data line at the appropriate level when an active transition occurs and to leave the data line at that level long enough for the data to be read properly The system should function reliably provided those two criteria are met Of course it 15 the convention for an asynchronous serial link to deal in bytes of data or in certain applications five or seven bit groups of data are used A normal RS232C interface is not used with groups of more than 8 bits of data With a synchronous system things are less rigid and the number of bits is tailored to match the requirements of the application The data can be 4 bit nibbles 32 bit long words or anything else within reason The system is not standardised and is designed specifically for a given application In practice this usually means designin
87. ated from 12 volts this versatile project triggers a 6 amp relay when the light intensity falls below an adjustable threshold Turn lights on around the house when it goes dark or trigger an alarm when a light is switched on Kit supplied with Kwik Kit PCB relay and all electronic components QM 1323 10 00 plus postage amp packing A budget priced meter with everything you need capacitance temperature and 10 on AC and DC compact and light weight with rugged moulded case e Data hold Relative measurement e Case included e Category Cat Ill 600V e Display 4000 count Ave RMS True RMS e Dimensions 137 H x 65 W x 35 D mm KC 5350 postage amp SACER When running AV cables for your home theatre system you may experience some signal loss over longer runs This kit will boost your video and audio signals preserving them for the highest quality transmission to your projector or large screen TV It boosts composite S Video and stereo audio signals Kit includes case PCB silk screened amp punched panels and all electronic components e Doosts Composite S Video and Stereo Audio e 9VAC 150mA required use our plugpack MP 3027 As published in EPE Magazine March 2006 POST amp PACKING CHARGES Order Value Cost 10 49 99 5 50 99 99 10 100 199 99 20 200 499 99 30 500 40 Note Products are despatched from Australia so local customs duty
88. ation Here s the procedure STEP 1 disconnect all nine spade connectors from the 22V OV 22V terminals at the output end of the power supply module STEP 2 disconnect the loudspeaker leads from the power amplifier modules STEP 3 connect an IEC mains power cable to the amplifier and use a 33 Constructional Adjusting the quiescent current through the power amplifiers 4 _ The quiescent current flowing the output stage of each power amplifier is initially adjusted by installing 1 50 5W re sistors in place of the fuses The voltage across one resistor is then monitored and trimpot VR1 adjusted for a reading of 1 68V equivalent to a quiescent current of 1 12A The easiest way to connect the resistors is to blow the fuse wires in a couple of spare M205 fuses then drill holes multimeter to confirm continuity be tween the earth pin of the plug and the chassis earth That done plug the cord into a mains socket and switch on Warning don t go poking around the rear of the IEC socket with power applied The metal strap that runs from the Live terminal to one end of the fuse carries 230V AC STEP 4 check the unregulated 22V rails at the output of the power sup ply module These rails should both be measured with respect to the terminal and should be a little high at around 24V since they are un loaded If the meter reads OV switch off immediately and recheck the connec tions to BR1
89. ation amp stable temperatures tem J range of 150 480 C ow voltage tron with Silicone cable Supply 240V Iron 24V 48W Model 167 570 52 23 Digital Multimeter Model 121 120 Price 11 47 A highly featured digital multitester for professional use Offers 30 ranges and 8 unctions including temper ature capacitance diode continuity and hFE measure ment Large 3 5 digit LCD display with automatic po larity indicator gt with shrouded test leads type temperature probe and shock proof rubber holster Technical Specifications voltage 00mV 1000V AC volts 2V 700V 0 8 DC current 2mA 20A 41 2 200 20 0 esistance 200 Ohms 20M hms 40 8 Capacitance 2000pF 20uF a Temperature 0 C 1000 C 1 5 Frequency 20kHz 1 Max 1999 battery Power supply 9V ag x ER x 40 mm T hekiectres amp Lightin PCB Production Processing Equipment We carry a large range of the photographic amp chemical Pines und equipment for PCB production a full list with ull technical specifications is available in our catalogue or vist our web site _ xposure units 2 x 8W Tubes 6 min timer 229 x 159mm yond area Model 332 002 95 00 4 x 15W Tubes 7 min timer 330 x 260mm working area 332 004 207 99 Chemical Processing Low cost plastic tray Process tanks feature
90. ault finding and repairing valve amplifiers A hands on approach to valve electronics classic and modern with a minimum of theory Planning fault finding and testing are each illustrated by step by step examples A unique hands on guide for anyone working with valve tube in USA audio equipment as an electronics experimenter audiophile or audio engineer Particular attention has been paid to answering questions commonly asked by newcomers to the world of the vacuum tube whether audio enthusiasts tackling their first build or more experienced amplifier designers seeking to learn the ropes of working with valves The practical side of this book is reinforced by numerous clear illustrations throughout 135 pages Order code 40 23 99 THEORY AND 368 pages REFERENCE THE EMERGENCE OF BROADCASTING IN BRITAIN Brian Hennessy The beginning of any great enterprise should be recorded for posterity Few knew that the Children s Hour Uncles Arthur Jeff and Caractacus were also the engineers who struggled by day to develop technical equipment and would soon become Assistant Controller Station Director and Organiser of Programmes for the BBC This is a very human account from the dawn of radio to the attainment of a Royal Charter in the late 1920s It tells of the struggles and frustrations of engineers in developing innovative equipment and of the great John Reith who battled with everyone to bring the
91. ay brightness for each driver Balancing is required because there may be labley2iGapacitomcGodes Value uF Code EIA Code IEC Code 100nF 0 1uF 104 100n 47nF 0 047uF 473 47n 10nF O 01uF 103 10n inF O 001uF 102 1nO 470pF NA 471 470p 22pF NA 22 22 variations in the current drive between IC1 and IC2 with dimming current Software The software files are available for download via EPE Downloads site access via www epemag com Pre programmed PICs are available from Magenta Electronics see their advert in this issue for contact details Construction The Digital Tachometer has two PC boards The control PC board is coded 699 and measures 117 x 101mm It is housed in a small instrument case measuring 140 x 110 x 35mm The display PC board is coded 700 and is 89mm in diameter Both boards are available from the EPE PCB Service Fig 5 shows the component over lay for the control board while Fig 6 shows the components on both sides of the display board While it is a single sided board ie copper pattern on one side only it does have components on both sides Begin construction by checking the PC boards for any shorts between tracks for breaks in the tracks and for correct sized holes Some components such as the screw terminals and the 3A diodes will require hole sizes that are larger than the standard 0 9mm required for most other components TablemiigResistormGolourGodes 2 4 Band Code 1 bro
92. be too bulky for some applications and the sensing tube cannot be altered in length Using thermostats Nearly all thermostats open when the trip point is reached This is lt 5 Although thermostats be used to directly control mains voltages we ve covered only low voltage DC switching in this article Make sure that you re up to speed with mains power wiring before attempting to use salvaged thermostats in high voltage appli cations If in any doubt yu MUST consult a qualified electrician or someone who is experienced with mains circuits otherwise the results could be fatal because they were designed to con trol heating elements that need to be switched off when the temperature ris es sufficiently In other words they re normally closed NC designs Only one pair of contacts is pro vided so what do we do when we want to turn something on rather than off when the trip point is reached This is easily achieved with a double throw or changeover relay and Fig 1 shows how it s wired It s also easy to add a couple of LEDs to indicate the switching status of the thermostat Fig 2 shows how to do this In this case LED1 lights when the fan is off thermostat closed while LED2 lights when the fan is running thermostat open The two 5600 resistors limit the current through each LED to about 18mA EPE Reproduced by arrangement with SIL
93. below the socket and damage it if you have to tug to release the wire from the holes Make surethat the arrangement of components and wire links is tidy with components snugly fitting close to the surface of the Protobloc This usually means providing more link wires than is perhaps necessary so as to avoid having wires going every which way across the board Never connect the battery leads to the top and bottom rails ofthe breadboard until you have carefully checked that all the component connections correspond to those on the circuit diagram Some components such as switches and relays do not have appropriate wire leads for insertion into the Protobloc If you have access to a soldering iron solder short lengths of single core 0 6mm diameter plastic sleeved wire to the terminals of these components Everyday Practical Electronics February 2009 Breadboarding Component Info LED1 to LED 6 red light emitting 52 pushswitch mM diode IC1 type 555 timer IC Viewed from the top an indented dot and a half moon shape at one end in dicates pin one The pins are numbered circuit diagram LEDs light in rapid succession too anti clockwise end fast for the eye to see the lighting of The longer lead is the anode the shorter lead is the cathode The anode lead is connected to the the push to make release to break outputs of IC2 as shown in the ing at pin 8 opposite C1 pol
94. c using the built in mic or direct from the phone line Char 4 acters displayed 16 character display as they are received and up to 32 numbers can be displayed by scroll ing the display All data written to the LCD is also sent to a serial output for connection to a computer Supply 9 12V DC Order Code PSU445 Main PCB 55x95mm Kit Order Code 3153KT 24 95 Assembled Order Code AS3153 34 95 Telephone Call Logger Stores over 2 500 x 11 digit DTMF numbers with time and date Records all buttons pressed during a call No need for any con nection to computer during operation but logged data can be downloaded into a PC via a serial port and saved to disk Includes a plastic case 130x100x30mm Supply 9 12V DC Order Code PSU445 Kit Order Code 3164KT 54 95 Assembled Order Code AS3164 69 95 ot Ne Products ere are a few of the most recent products dded to our range See website or join our mail Newsletter for all the latest news Bipolar Stepper Motor Chopper Driver New bipolar chopper driver gives better performance from your stepper motors It uses a dual full bridge mo tor driver based on SGS Thompson chips L297 amp L298 Motor current for each phase is set using an on board potenti ometer Can handle motor winding currents of up to 2 Amps per phase Operates from a DC supply voltage of 9 36V All basic motor controls provided including full or half step pi
95. column on EPE Online where more bonus material is available including further details of ClearMyMail news of the BT IPlate adaptor plate that may boost speeds for some broadband customers You will also find hyperlinks to support Net Work as well You can email me at alan epemag demon co uk ILE ACE Be P Em Riu d am 11 Everyday Practical Electronics February 2009 DIRECT BOOK SERVICE Electronics Teach In Mike Tooley A broad based introduction to electronics find out how circuits work and what goes on inside them Plus 15 easy to build projects The 152 page A4 book comes with a free CD ROM containing the whole Teach In 2006 series originally published in EPE in PDF form interactive quizzes to test your knowledge TINA circuitsimulation software a limited version plus a specially written TINA Tutorial together with simulations of the circuits in the Teach In series plus Flowcode a limited version a high level programming system for PIC microcontrollers based on flowcharts The Teach In series covers everything from Electric Current through to Microprocessors and Microcontrollers and each part includes demonstration circuits to build on breadboards or to simulate on your PC In addition to the Teach In series the book includes 15 CMOS based simple projects from the Back To Basics series by Bart Trepak these are Fridge Freezer Alarm Water Level Detector Bur
96. d the trans former leads are all the correct length to reach their destinations and are Everyday Practical Electronics February 2009 Reproduced by arrangement with SILICON CHIP magazine 2009 www siliconchip com au pre fitted with female spade quick connects We ll deal with the second ary wiring first all you have to do is twist the various lead pairs together and plug them into the relevant quick connect terminals on bridge rectifier BR1 and the power supply module First twist the white and black leads together to form the OV centre tap and connect them to the adjacent GND point on the power supply module That done twist the red and 31 Constructional Project The RCA phono input sockets must be fully insulated from the chassis The audio cable shield wires go to the individual solder lugs do not join them or connect them to chassis at this point as this would create an earth loop The transformer s red and yellow secondary leads plug into the piggyback connector at the bridge rectifier BR1 as shown here They should then be strapped using cable ties so that the connectors cannot short against BR1 s metal case yellow secondary leads together and plug them into the piggyback spade connectors on the AC terminals of BR1 There s one important wrinkle you have to watch out for when plugging in the transformer secondary leads it s all to easy to push the male lug of each pigg
97. d Only c SC ttt 1 um p r ae gt 2465A 4 Ch 350MHZ Delay Sweep Cursors etc 2465B 4 Ch 400MHZ Delay Sweep Cursors etc 2465B Rack Mount 4 Ch 400MHZ Delay Sweep GUTS rl M M 2467 4 Ch 350MHZ Delay Sweep Cursors etc TAS 465 Dual Trace 100MHZ Delay Cursors TAS 485 4 Ch 200MHZ Delay Cursors HP 54501A Digitising 2 2 Ch 100MHZ 10 MS S 54502A Digitising 2 Ch 400MHZ 400 MS S 54600A Dual Trace 100MHZ 20 MS S 195 54600B Dual Trace 100MHZ 20 MS S 225 Check out our website 1 0005 of items currently in stock Everyday Practical Electronics February 2009 PHILLIPS PM3052 Rack Mount Dual Trace 60MHZ PM3055 2 1 Ch 60MHZ dual TB Delay Autoset PM3065 2 1 Ch 100MHZ dual TB Delay Autoset 125 PM3084 4 Ch 100MHZ Delay TB PM3335 Digital Storage Dual Trace 60 20 MS S PM3337Rack Mount Digital Storage Dual Trace 60MHZ 20 MS S PM3365A Digital Storage Dual Trace 100MHZ 100 HITACHI V222 Dual Trace 20MHZ DC Offset Alt Mag V522 Dual Trace 50MHZ DC Offset Alt Mag V665 Dual Trace 60MHZ Delay Sweep Cursors etc 75 V1065 Dual Trace 100MHZ Delay Sweep Cursors etc 203 4 Dual Trace 20MHZ Component Tester 203 6 Dual Trace 2OMHZ Component Tester 305 Dual Trace O3MHZ Analogue Digital 40 MS S per Channel Component Tester 604 2 Dual Trace 60MHZ Component Tester Used Equipment GUARANTEED Most Manuals supplied Please check avai
98. d com BOWOOD ELECTRONICS LTD Suppliers of Electronic Components Place a secure order on our website or call our sales line All major credit cards accepted Web www bowood electronics co uk Unit 10 Boythorpe Business Park Dock Walk Chesterfield Derbyshire S40 2QR Sales 01246 200222 Send 60p stamp for catalogue Miscellaneous VALVES AND ALLIED COMPONENTS IN STOCK Phone for free list Valves books and magazines wanted Geoff Davies Everyday Practical Electronics February 2009 JIN LY INCLUDING P amp P FROM OUR DIRECT BOOK SERVICE Radio tel 01788 574774 71 Europe s Largest Surplus Store 20 000 000 items line NOW New items added dail Established for over 25 years UK company Display Electronics prides itself on offering a massive range of electronic and associated electro mechanical equipment and parts to the Hobbyist Educational and Industrial user Many current and obsolete hard to get parts are available from our vast stocks which include 6 000 000 Semiconductors 5 000 Power Supplies 25 000 Electric Motors 10 000 Connectors 100 000 Relays amp Contactors 2000 Rack Cabinets amp Accessories 4000 Items of Test Equipment 5000 Hard Disk Drives Display Electronics Telephone 29 35 Osborne Road 44 020 8653 3333 Thornton Heath Surrey UK CR7 8PD Fax 44 020 8653 8888 Rechargeable Batteries With Solder Tags NIMH NICAD AA 2000mAh AA 650mAh PP3
99. d should not be connected direct to ordinary logic inputs 44 such as the one shown in the circuit diagram of Fig 2 Transistor TR1 is switched on when the RS232C output is at 12V sending its collector c to little more than the OV supply voltage Transistor TR1 is switched off when the driving output line goes to 12V and R3 then pulls the output of the circuit high Resistor R1 and diode D1 limit the input voltage to TRI at about 0 7V and protect it from an excessive reverse There is an inversion through this circuit so the software must be designed to take this into account Fig 1 The DTR and RTS lines at pins 4 and 7 respectively can be directly controlled by a Visual BASIC program This enables a basic synchronous link to be produced D1 144148 Gnd MORE ON SERIAL PORT COMPATIBILITY Essentially the same circuit can be used to control a relay and a suitably modified version of the circuit is shown in Fig 3 As before operates as a simple common emitter switch that is turned on when the RS232C output is at 12V and turned off when it is at 12V In this case though the load for TRI 15 the relay coil and the relay is therefore switched on when the RS232C output is set at 12V Diode D2 protects the circuit from the high reverse voltage spike that occurs when the relay is switched off The supply potential is given as 12V in Fig 3 which assumes that the relay has a 12V coil The supply
100. direction The range of control is from fully OFF to fully ON in both directions The direction and speed are controlled using a single potentiometer Screw terminal block for connections Kit Order Code 3166v2KT 17 95 Assembled Order Code AS3166v2 27 95 AC Motor Speed Controller 700W Reliable and simple to install project that allows you to adjust the speed of an electric drill or single phase 230V AC motor rated up to 700 Watts Simply turn the potentiometer to adjust the motors RPM PCB 48x65mm Not suitable for use with brushless AC motors Kit Order Code 1074KT 12 95 Assembled Order Code AS1074 18 95 Box Order Code 2074BX 5 95 QUASAR electronics Get Plugged In Electronic Project Labs Great introduction to the world of electron ics Ideal gift for budding electronics expert 500 in 1 Electronic Project Lab Top of the range Com plete self contained elec tronics course Takes you from beginner to A Level standard and beyond Contains all the hardware and manuals to assemble 500 projects You get 3 comprehensive course books total 368 pages Hardware Entry Course Hardware Advanced Course and a microprocessor based Software Program ming Course Each book has individual circuit explanations schematic and connection dia grams Suitable for age 12 Order Code EPL500 149 95 Also available 30 in 1 16 95 50 in 1 21 95 75 in 1 32 95 130 i
101. downloadable files of all the programs and subroutines program listings for the Quester and the Gantry robots that are too long to be included in the book 366 pages Order code NE46 21 99 NEWNES INTERFACING COMPANION Tony Fischer Cripps A uniquely concise and practical guide to the hardware applications and design issues involved in computer interfacing and the use of transducers and instrumentation Newnes Interfacing Companion presents the essential information needed to design a PC based interfacing system fromthe selection of suitable transducers to collection of data and the appropriate signal processing and conditioning Contents Part 1 Transducers Measurement systems Temperature Light Position and motion Force pressure and flow Part 2 Interfacing Number systems Computer architecture Assembly language Interfacing A to D and D to A conversions Data communications Programmable logic controllers Data acquisition project Part 3 Signal processing Transfer function Active filters Instrumentation amplifier Noise Digital signal processing 295 pages Order code NE38 35 99 67 THEORY AND REFERENCE THE AMATEUR SCIENTIST CD ROM The complete collection of The Amateur Scientist articles from Scientific American magazine Over 1 000 classic science projects from a renowned source of winning projects All projects are rated for cost difficulty and possible hazards Plus over 1 000 pages of help
102. e 36 scale you could have dusk night and day ranges marked Another use is in battery powered equipment Because the meter draws very little power it could be used in many applications to permanently display the battery voltage That way you ll always know if you ve got a battery that s nearing the end of its charge or its life Components You ll need only two components as well as access to a computer just about any image manipulation pro gram a scanner and a printer You ll also temporarily need a plugpack a 10k 2 pot and a multimeter to carry out the scale calibration The two electronic components required are an analogue VU meter from a discarded audio cassette deck and a 100k multiturn trimpot used here as a variable resistor Old cassette decks with large illumi nated VU meters turn up all the time in car boot sales and at the local tip It is extremely rare for the VU meters to be dead so you can be fairly safe in collecting any old cassette deck for this purpose Try to obtain a deck that has two separate meters one for each stereo channel rather than one that has them combined into a single display VU meters are typically moving coil voltmeters that have a very high sensitivity This means that it takes very little voltage to move the needle across the full scale typically just 0 3V to 0 4V Their coil resistance is very high at around 6000 to 7000 Plug
103. e 470uF capacitor The cathode side of the diode also supplies the 5V 14 1 90mm female stormwater fitting 90mm ID x 21mm 1 40mm suction cap with 5mm diameter x 15mm locking pin 1 90mm diameter neutral tint 1 5mm display filter with display masking cut for a tight fit inside the 90mm PVC pipe 1 90mm diameter piece of 0 5mm galvanised steel 1 piece of 25 x 42mm x 1mm aluminium 4 M3 tapped 6mm long Nylon spacers Semiconductors 2 M5451B7 PDIP40 package IC1 1C2 1 PIC16F88 I P microcontroller programmed with ledtacho hex IC3 1 MC34063 DC DC converter IC4 1 LM2940CT 5 low dropout TO 220 3 terminal 5V regulator REG1 1 TIP42C PNPtransistor Q1 2 BC557 PNPtransistors Q2 Q3 4 common anode 12 5mm red 7 segment displays LTS542R or equivalent DISP1 DISP4 Note for sunlight readable displays use the Agilent 16mcd 20mA HDSP H151 from Farnell Cat 100 3141 or 264 313 www farnellinone com au 28 green 5mm LEDs LED1 LED27 LED34 Note use gt 400mcd 20 angle and 10mA for sunlight readability 6 red 5mm LEDs LED28 LED32 LED35 Note use 400mcd 20 angle and 10mA for sunlight readability regulator REG1 an LM2940CT 5 This is a low dropout regulator intended for automotive use with input protection against supply transients The 1000 series resistor supplying REG1 limits peak currents into the transient protec tion circuitry Dimming As mentioned display drivers
104. e at 1 7V This fixes the Everyday Practical Electronics February 2009 je ssaujusSriq enprarpurt YIIYM pue LD 51 e dsrp paseq sr uot as ay 914 40 lt lt 1 V 1dSId Constructional Project I JUL 18 Ld e IDE D NO Wadd oxaz A ZEA Ledai oead 62051 871 zaJ 9 31 cav eq31 6d3122031 L 7G31 O71 6143181937 210351 9 151 slay elan L Ld3101031 9 31 zan 1997 15 Everyday Practical Electronics February 2009 Constructional voltage across trimpots VR2 and VR3 at 10V 1 7V or 8 3V The resistances of VR2 VR3 therefore set the current through the collectors and emitters of Q2 and Q3 This in turn sets the bright ness for display drivers IC1 and IC2 respectively In low ambient light the LDR resist ance rises and so the emitter voltage rises Current sources Q2 and Q3 therefore drop their collector current because there is less voltage across VR2 and VR3 and so the displays dim Trimpots VR4 and VR5 shunt Q2 and Q3 to set the minimum cur rent flow into IC1 and IC2 when the LDR is in darkness which results in Q2 and Q3 being fully switched off Trimpot VR6 is included to adjust the threshold where the LDR starts dimming The individual adjustments of dim ming current for IC1 and IC2 are in cluded to allow balancing the displ
105. e gifts are included Order on line from www epemag com or by phone fax email or post BACK ISSUES CD ROM ORDER FORM Please send me the following Back Issue CD ROMs Price 16 45 each 29 95 for Five Year CD ROM postage to anywhere in the world Post DM LJ enclose cheque P O bank draft to the value of please charge my Visa Mastercard Maestro CardiNo M nes Card Secur ity 257 The last 3 digits on or just under the signature strip Valid a eee Dele S l Maestro Issue No SEND TO Everyday Practical Electronics Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Tel 01202 873872 Fax 01202 874562 E mail orders epemag wimborne co uk Payments must be by card or in Sterling cheque or bank draft drawn on a UK bank Normally supplied within seven days of receipt of order Recycle It BY JULIAN EDGAR Salvaging and using common thermostats Thermostats are attached to or buried in lots of consumer items and are easy to salvage Here s a look at the common types and some hints on how they re used EED to control a fan heater or pump on the basis of tempera ture It s a common requirement that can be achieved using an electronic circuit with a thermocouple or therm istor input However it s much cheaper and easier to use a thermostat salvaged fro
106. e the number correct REST OF THE WORLD AIRMAIL er 29 00 756 00 15 valid from Exp date m m m m m m m m Yes would like a sample copy for 3 75 Maestro Issue ERE A free issue is available for download from www radiobygones com em CELERE Yes would like to take out a subscription for One year 6 issues Two years 12 issues 2202002 ee payable to Wimborne Publishing Ltd Post gt Please debit my Visa Mastercard Maestro card If you do not wish to cut your issue send a letter or a copy of this form 37 ver the last few articles we have developed some Ethernet hardware and built of the box software to provide a simple webserver Now it s time to write our own software in the form of an embedded webserver that can provide secure remote control of your electrical appliances from anywhere in the world And it s only going to take just a few lines of code and some minor modification to the Microchip supplied software The webserver is going to be based on the hardware design covered in last month s article which explains why we added a relay into the circuit Just what kind of appliance you can control will depend very much on the choice of relay and your hardware skills We are only interested in the software aspects
107. e two leads together and fit one end of each lead with a piggyback crimp connector see photo opposite page That done plug these into the AC terminals of the bridge rectifier then route the leads to the loudspeaker protector and trim them to length Finally strip about 5mm of insulation from the ends of the leads and tin them before connecting them to the screw terminal block CON2 If you route these leads as shown in the photos they can be secured to the chassis using a cable tie that passes through one ofthe transformer ventila tion slots A second cable tie adjacent to CON2 is also a good idea Audio input wiring The audio input signal leads can now be run from the rear panel to the preamplifier These leads should be run using figure 8 stereo screened audio cable ie with the inner conduc tor individually shielded Route these leads exactly as shown and secure them using cable ties and ad hesive cable tie mounts The locations of the latter are indicated on Fig 1 MWhereltolbuyicompletecandgshonbfonmiits A kit of parts for the 20W Stereo Class A Amplifier Cat K5125 is available from Altronics 174 Roe St Perth WA 6000 Australia The kit is complete and includes the five modules unassembled and a pre punched steel chassis similar to that shown in the photographs Alternatively you can purchase individual kit modules but not the chassis separately Check the Altronics website at for further detail
108. ectronics equipment With this fully illustrated simple to use guide you will get a grasp on the workings of the electronic world that surrounds you and even learn to make your own repairs You don t need any technical experience This book gives you Clear explanations of how things work written in everyday language Easy to follow illustrated instructions on using test equipment to diagnose problems Guidelines to help you decide for or against professional repair Tips on protecting your expensive equipment from lightning and other electrical damage lubrication and maintenance suggestions Covers colour TVs VCRs radios PCs CD players printers telephones monitors camcorders satellite dishes and much more Order code 200 pages 228 pages 394 pages 21 99 VINTAGE RADIOS Tony Thompson Since the 1920s the radio set has been an important part of most people s lives In the thirties and forties the wireless was an important piece of furniture and a potent symbol of status beautifully made floor standing and table top sets in veneered wood and trendy Bakelite became the focal points of living rooms up and down the land After the war the emphasis began to change towards portability and the change from valves to transistors in the 1960s changed the radio into a more useful but far less interesting object The book tells the collector and the armchair wireless enthusiast everything he or she needs to know abo
109. electrically operated pumps and or heaters with thermostat control suitable ET20 Low cost Etching Tank with heater amp pump 49 84 Universal Tank with heate Model 333 007 160 00 Bubble etch Tank with heater amp bubble ne Model 333 004 196 00 Any of these items carriage 5 50 PCB Production Tools Drill Bits HSS parallel shank bits available in sizes from 0 3mm to 0 3 0 95mm 0 05mm steps 0 60ea 4 00 10 1 0 2 0mm in 0 1mm steps 0 40ea 3 60 10 HSS Reduced shank 2 35mm bit available in sizes from 0 6mm to 1 7mm 0 1 steps 0 84ea 7 60 10 Reground Tungsten carbide reduced shank available in sizes from 0 6 to 1 6mm in 0 1mm steps 1 90 Drilling Machines Expo Zircon 12V drill 3 8mm capacity 11900rpm 14 20 Minicraft MX1 230V 8000 21000rpm with chuck amp collet Model EPE270 390 Normal price 48 51 SPECIAL PRICE amp 31 02 Servisol Products Aerosols Switch Cleaner Freezer Foam Cleanser Cleaner lubricant Vide Head Cleaner Aero Klene Aero Duster Isopropyl alcohol Heatsink Compound Heatsink Compound Silicone grease Bench Power Supplies A range of single bench power sup pies with variable voltage amp current limiting Features hort circuit and Foldback overload protection Metal case with on off switch outputs via Red Black amp Green Earth 4mm shrouded sockets LN ow d Model 461 540 0 20V 2A 0 30V0 3A
110. elow and take 40 off the total including VAT price SOFTWARE FOR 16 Series PlCmicro Version 4 The C for PlCmicro microcontrollers CD ROM is designed for students and professionals who need to learn how to program embedded microcontrollers in C The CD contains a course as well as all the software tools needed to create Hex code for a wide range of PICmicro devices including a full C compiler for a wide range of devices Although the course focuses on the use of the PlCmicro microcontrollers this CD ROM will provide a good grounding in C programming for any microcontroller Complete course in C as wel as C programming for PlCmicro microcontrollers e Highly interactive course e Virtual C PlCmicro improves understanding e Includes a C compiler for a wide range of PlCmicro devices e Includes full Integrated Development Environment e Includes MPLAB software e Compatible with most PICmicro programmers e Includes a compiler for all the PICmicro devices Minimum system requirements for these items Pentium PC running Windows 98 NT 2000 ME XP CD ROM drive 64MB RAM 10MB hard disk space FLOWCODE FOR PiCmicro V3 Flowcode is a very high level language programming system for PlCmicro microcontrollers based flowcharts Flowcode allows you to design and simulate complex systems in a matter of minutes A Powerful language that uses macros to facilitate the control of devices li
111. ensure that all sections of the case including the side panels and the front and rear panels Everyday Practical Electronics February 2009 are correctly earthed and that means ensuring they make good electrical contact with each other There are two reasons for this 1 All sections of the case must be con nected to the mains earth to ensure safety 2 Correct earthing is essential to keep RF interference out of the audio circuitry The first job is to ensure that the two side panels the front and rear pan els and the lid are all earthed to the bottom section of the chassis This is done by using an oversize drill to remove the powder coating from the countersunk screw holes Use a drill that s slightly smaller in diameter than the screw heads and be sure to remove the powder coating right back to the bare metal Don t just do this for one or two holes do it for all the holes in each panel Provided you use a drill that s not too big the bare metal will later be covered by the screw heads Next scrape away the powder coating around the screw holes in side the panels the underside of the lid and from the matching contact areas around the screw holes in the chassis This includes the contact areas around the screw holes on the inside folded sections of the front panel That way when the case is as sembled earthing takes place via the 23 Constructional Fig 1 follow this diagram and the y phot
112. er amp Remote Volume Control This month we show you how to assemble everything into a custom made steel chassis that s been de signed by Altronics www altronics com au This precision laser cut chassis is supplied with all the holes drilled and with pre punched front and rear panels with screened lettering This case is similar to their 2U deluxe rack cases but is much deeper and features a bevelled front panel The completed amplifier looks very professional although at 420 x 425 x 88mm W x D x H it s really quite a large unit This size is necessary to accommodate the large finned heatsinks used for the power amplifiers and to allow the various modules to be logically placed and separated inside the chassis The large chassis size is also im portant to aid ventilation as the main heatsinks run quite hot in operation about 30 above ambient In addi tion the bottom of the chassis and the lid have large ventilation slots which line up with the heatsink fins to allow the air to circulate through them That s one of the drawbacks of a class A amplifier they generate lots of heat that has to be dissipated Now let s assume that you ve com pleted all the modules and that you re ready to mount them in the chassis and install the wiring Here s how to go about it Preparing the case The supplied case has a tough pow der coating that s also a good insulator However you must
113. ere the curve changes from concave to convex Here also the curves for the various temperatures cross over one another the temperature coefficient is zero changing the temperature does not change the drain current at this V about 3 8V on Fig 7 Below this value of V the drain current has a positive temperature coefficient and above it it is negative The basic formula for the drain current of a saturated MOSFET is this formula is gain parameter which depends on the size shape of the transistor width length ratio and gate oxide thickness and on the mobility of charge carriers in the channel Mobility describes the ease with which electrons or holes move when under the influence of an electric field applied voltage For MOSFET channels the mobility decreases with temperature causing k to have a negative temperature coefficient simple explanation Although there is more than one mechanism at work a simple explanation for this is that at higher temperatures the increased vibration of the silicon crystal lattice means that electrons or holes cannot move so easily The formula also depends on the threshold voltage V As we see from Fig 1 this has a negative temp erature coefficient but note that it 1s subtracted from V in the formula An increase in temperature will decrease V increasing Vos Vp and hence increasing I Thus we have two opposing effects mobility v
114. ert IS project produces an inter mittent audio alarm when the air temperature reaches the freezing point of water that is 0 in normal conditions The temperature sensing device is a thermistor TH1 the resistance of which decreases with increasing temperature The circuit diagram shown in Fig 5 1 may be regarded as made up of two main building blocks The first building block acts as atemperature sensitive electron ic switch based on operational amplifier op amp IC1 which is activated when the thermistor reaches 0 C Once acti vated it energises the second building block comprising two 555 timers IC2 and IC3 that are interconnected as two coupled astables Together they pro duce a loud pulsing audio alarm from loudspeaker LS1 when the thermistor s temperature falls to 0 C How it works In order to understand how the cir cuit works focus first on IC1 which is connected as an electronic switch Notice that the voltage divider action of resistors R1 and R2 provide a fixed voltage on the non inverting pin 3 of IC1 This voltage is compared with the variable voltage on its inverting pin 2 which is determined by the resistance of the thermistor TH1 and of the set ting of potentiometer VR1 which is used as a variable resistor Once this variable voltage falls below the voltage on IC1 pin 3 the output of IC1 pin 6 rises sharply to near the positive supply voltage and is sensed by pin 4 of IC2
115. est amp Control PC based measure amp control units Analogue Digital data loggers from 49 Robot and Controller Kits Micros LCD Relay boards Free Software From 29 Plura Embedded Controller Learn more at wWww audon co uk Budget Test Equipment Scopes Multimeters Function Generators from 99 PC Weather Stations Wind speed direction temp humidity rainfall Free software From 59 P Electronics www audon co uk 44 0 115 925 8412 Fax 44 0 115 925 9757 Everyday Practical Electronics February 2009 SHERWOOD ELECTRONICS Buy 10 x 1 Special Packs and choose another one FREE 15 x 5mm Red LEDs 12 x 5mm Green LEDs 12 x 5mm Yellow LEDs 25 x 5mm 1 part LED clips 15 x 3mm Red LEDs 12 x 3mm Green LEDs 10 x 3mm Yellow LEDs 25 x 3mm 1 part LED clips SP10 100 x 1N4148 diodes SP11 30 x 1N4001 diodes SP12 30 x 1N4002 diodes SP18 20 x BC182B transistors SP20 20 x BC184B transistors SP23 20 x BC549B transistors SP24 4 x CMOS 4001 SP25 4 x 555 timers SP26 4 x 741 Op Amps SP28 4 x CMOS 4011 SP29 4 x CMOS 4013 SP33 4 x CMOS 4081 SP34 20 x 1N914 diodes SP36 25 x 10 25V radial elect caps SP37 12 x 100 35V radial elect caps SP38 15 x 47 25V radial elect caps SP39 10 x 470 16V radial elect caps SP40 15 x BC237 transistors SP41 20 x Mixed transistors SP42 200 x Mixed 0 25W C F resistors SP47 5 x Min PB switches SP49 4 x 5 metres stranded core wire SP102
116. est software and DMX Light Player soft ware is included a DLL is pro vided to write your own software Stand alone test func tion that outputs all 512 channels at a time with adjustable levels Supplied with case lead amp CDROM K8062 Kit 46 95 VM116 Assembled 49 95 Other Velleman Instruments HSP10 Handheld Scope 94 95 HSP10SE Handheld Scope inc case 105 00 HSP4O Personel Scope inc case 189 95 PCS500A PC Digital Storage Scope 270 00 PPS 10 Personel Poscket Scope 99 00 VPS10 Panel Scope 99 00 PCS 10 4 Channel Data Bagger 29 95 Tel 0191 2514363 Fax 0191 2522296 sales esr co uk Station Road 5 Cullercoats Tyne amp Wear 4PQ Remote Control Transmitter For use with the K8057 VM109 2 channel RF receivers Generates unique 32 bit code more than 1 000 000 000 unique codes code can easily be changed for safety purposes choose continuous or burst transmission LED indicator K8059 Kit Remote Control Receiver Two relay contact outputs for use with K8059 and VM108 two chan nel RF codelock transmitters tog gle or pulse function selectable per output can learn a unique 32 bit code from the transmitters store up to 31 transmitters LED indicators for outputs and functions K8057 Kit CA Ea 8 95 12 55 Remote Control Transmitter Compact 2 button IR keychain remote compati with most Velleman IR receivers 2 powerful SHIR LEDs
117. ether with the brown primary lead Start of the primary lead s quick connector and twist the leads together all the way back to the base of the transformer STEP 4 Slip a320mm length of 10mm diameter heatshrink tubing over this twisted pair and lightly shrink it into place using a hot air gun Be careful not to apply too much heat you don t want the cable insulation to melt gently does it STEP 5 Secure this cable in position using the nylon P clamps as shown in Fig 1 Note the orientation of the P clamps cable should run adjacent to the power supply board so that it is well away from the righthand power amplifier The switch end of the cable runs under the preamp and must be routed exactly as shown STEP 6 Trim the switch end of the added brown lead to the same length as the brown primary lead and crimp on a fully insulated spade connector Make sure that all the wire strands go inside the connector a strand outside the connector will be dangerous STEP 7 Attach the front panel to the am plifier chassis and clip the mains switch into position The two switch terminals go towards the top of the panel STEP 8 Connect the two spade con nectors to the switch terminals The transformer s primary lead goes to the top terminal Use a cable tie to secure the leads at the switch terminal STEP 9 Twist the added brown lead with the blue primary lead all the way to the latter s spade connector ST
118. even build an oscilloscope The contents include a description of the basic oscillscope Advanced real time oscilloscope Accessories Using oscilloscopes Sampling oscilloscopes Digital storage oscilloscopes Oscilloscopes for special purposes How oscillocopes work 1 the CRT How oscilloscopes work 2 circuitry How oscilloscopes work 3 storage CRTs plus a listing of Oscilloscope manufacturers and suppliers Order code NE37 288 pages 24 00 Rad iOS aes gc 68 PRACTICAL ELECTRONIC FAULT FINDING AND TROUBLESHOOTING Robin Pain To be a real fault finder you must be able to get a feel for what is going on in the circuit you are examining In this book Robin Pain explains the basic techniques needed to be a fault finder Simple circuit examples are used to illustrate principles and concepts fundamental to the process of fault finding This is not a book of theory it is a book of practical tips hints and rules of thumb all of which will equip the reader to tackle any job You may be an engineer or technician in search of information and guidance a college student a hobbyist building a project from a magazine or simply a keen self taught amateur who is interested in electronic fault finding but finds books on the subject too mathematical or specialised The fundamental principles of analogue and digital fault finding are described although of course there is no such thing as a digital fault all fa
119. f required see the Back Issues page for details WE DO NOT SUPPLY KITS OR COMPONENTS FOR OUR PROJECTS Please check price and availability in the latest issue A large number of older boards are listed on and can be ordered from our website Boards can only be supplied on a payment with order basis PRO ECTTITLE OCTCBRR 07 Simple Seismograph V8 Doorbell Main Board Display Board Standby Power Saver Transmitter Receiver PSU NOVEMBER 07 Vehicle Voltage Monitor USB Electrocardiograph Inductance amp Q Factor Meter Experimenter s Audio System Main Board PSU Teach In 08 Master Control Board DECEMBER 07 iPod or MP3 Player Charger AVR ISP Socketboard PIC Speech Synthesiser Playback Record JANUARY 08 Serial I O Controller MIDI Drum Kit Main Board Display Phone Fax Missed Call Alert PIC Carillon FEBRUARY 08 MIDI Drum Kit Optical Sensor Studio Series Stereo Preamplifier Pre Amp PSU Electrosmog Sniffer MARCH 08 Fluorescent Tube Driver Studio Series Stereo Headphone Amplifier APRIL 08 Studio Series Remote Control Module MIDI Activity Detector PIC In Circuit Programming Add On PC Controlled Burglar Alarm Main Board Display Board MAY 08 PC Controlled Burglar Alarm Keypad Electric Mobility Buggy Monitor Mini Theremin JUNE O8 Monopoly Money Universal High Energy LED Lighting
120. f writing to them using Visual BASIC is also exactly the same for conventional and virtual ports The obvious way of sending data to the outside world using a serial port is to write bytes of data to the port so that they are sent in standard asynchronous form and then decoded by the receiving device in the normal way However this is not necessarily the best way of doing things for every application Using an RS232C link tends to be more straightforward in theory than in practice and it is not something you ever hear described as straightforward previous Interface article covered the Level conversion As explained in the previous Interface article two of the handshake outputs of the port are under direct software control and can therefore be used as general purpose outputs The two handshake outputs are the DTR and RTS lines which are respectively at pins 4 and 7 of the serial port see Fig 1 One slight complication when using these is that they are at standard RS232C signal levels which are approximately 12V True and 12V False It is therefore necessary to process these lines using RS232C line receivers in order to obtain signals at conventional logic levels For many purposes a simple common emitter switching stage is all that is needed RI ac 47 Output VY DI 1N4148 Gnd Fig 2 A simple line receiver circuit that is suitable for many applications The outputs of an RS232C port are about 12V an
121. fect Transistors It came up during discussion on another forum that the gate source threshold of MOSFETs can vary with temperature Lo and behold page three of the datasheet for the BSI70 shows a graph datasheet Fig 6 demonstrating this see www fairchildsemi com ds BS BS170 pdf None of us could think of an explanation Anyone here like to hazard a guess The graph in question is shown in Fig 1 The BS170 is an N channel enhancement mode field effect transistor which according to the datasheet is manufactured using DMOS technology These devices have low on state resistance and provide reliable and fast switching performance and can handle up to 500mA DC They are suitable for low voltage low current applications such as small servo motor control power MOSFET gate drivers and other switching applications Discussion on the forum in response to this post raised issues such as parallel connection of devices thermal runaway including differences between MOSFETs and BJTs bipolar junction transistors in this respect Parallel connection of transistors seems like a great way to provide high power handling capability see Fig 2 However this will only work if the transistors share the power handling equally and consistently any imbalance may lead to destruction of the devices So this month we will take a look at parallel lt a gt ey de Ug A fe 2
122. for a range of up to 15m 16 channels allow use of multiple transmitters in one room easy channel configuration no jumpers required 6 25 MKI 62 Mini Kit Remote Control Receiver Two channels with relay output channel and reception indication through LEDs toggle pulse selec tion for each channel learn mode for channel ID all settings are stored in EEPROM compatible with most Velleman Kit IR remotes MK161 Mini Kit 7 95 3 30V 3A Power Supply Suitable as a power supply for all common Velleman kits using a sta bilised DC voltage between 3 and 30V 3A max Of course this pow er supply unit can also be used for other purposes By replacing the trimmer by a potentiometer it may even be used as an adjustable power supply unit Supplied with heat sink 19 95 K7203 Kit Sound to Light Unit Low mid and high channels Sensitivity adjustment channel LED indication per channel Attractive translu cent enclosure Microphone includ ed Noise suppressed according to EN55015 K8017 Kit 27 55 Clap On Off Switch Operate your lighting simply by clapping your hands Good immunity against sur rounding noises l clap 2 clap mode selection 2 clap mode features built in safety turn off timer approx 5h output relay pulse or toggle selection MK139 Mini Kit Voice Changer Make your voice sound like a robot add vibrato effect use the pitch buttons and make you
123. for both manuals saving 10 by ordering both together FULL NAME ADDRESS POSTCODE SIGNATURE Please charge my Visa Mastercard Maestro Card No Valid From Maestro Issue No Card Security Code Expiry Date e Everyday Practical Electronics February 2009 enclose cheque PO in UK pounds payable to Wimborne Publishing Ltd The last 3 digits on or just under the signature strip lllo lll ll L1 ll Ta gt ORDER FORM L i Simply complete and return the order form with your payment to the following address i Wimborne Publishing Ltd p Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Price includes postage to anywhere in the World We will happily exchange any faulty CD ROMs but since the content can be printed out we do not offer a refund on these items m Your will be posted to you by first class mail or airmail normally within four working days of receipt of your order aay aaa 43 By Robert Penfold use of the free programming language Visual BASIC Express Edition 2008 to write data to a serial port The latter could be a conventional PC RS232C port but these days it would more probably be a virtual type added to a USB port or PCI expansion slot It does not really matter which type of serial port is used since they are effectively the same once integrated into the operating system using the correct driver software The method o
124. ful science techniques that never appeared in Scientific American Exciting science projects in Astronomy Earth Science Biology Physics Chemistry Weather and much more The most complete resource ever assembled for hobbyists and professionals looking for novel solutions to research problems Includes extensive Science Software Library with even more science tools Suitable for Mac Windows Linux or UNIX 32MB RAM minimum Netscape 4 0 or higher or Internet Explorer 4 0 or higher Order code AS1 CD ROM BEBOP BYTES BACK and the Beboputer Computer Simulator CD ROM Clive Max Maxfield and Alvin Brown This follow on to Bebop to the Boolean Boogie is a multimedia extravaganza of information about how computers work It picks up where Bebop left off guiding you through the fascinating world of computer design and you ll have a few chuckles if not belly laughs along the way In addition to over 200 megabytes of mega cool multimedia the CD ROM contains a virtual microcomputer simulating the motherboard and standard computer peripherals in an extremely realistic manner In addition to a wealth of technical information myriad nuggets of trivia and hundreds of carefully drawn illustrations the CD ROM contains a set of lab experiments for the virtual microcomputer that let you recreate the experiences of early computer pioneers if you re the slightest bit interested in the inner workings of computers then d
125. g the receiving device first and then writing the software for the PC to match this design Missing link Although a synchronous link can have as little as two connecting lines plus an earth connection real world links often have an additional C4 line The problem with a simple twin line system is that it can get out 1o0n of synchronisation if there are any spurious pulses on the two lines or cs it may never become properly synchronised if there are any such pulses l on initially such as when the computer is booted Each block of decoded data is then the end of one block and the beginning of the next one giving totally scrambled and erroneous results The hardware solution is to have a third output from the sending device that is used to reset the receiving equipment prior to a new set of data being sent This method is not a practical proposition using the handshake outputs of an RS232C port since there are only two outputs that are under direct software control However it is still possible to have some form of error checking but this has to rely on software routines at the receiving device instead of an extra wire in the link For example in a practical system there will often be a relatively long gap between each set of bits This gap can be detected by a software routine at the receiving equipment and used as a reset signal Another ploy is to set one or both of the lines at a certain level before starting the transmission of data
126. glar Alarm Scarecrow Digital Lock Doorchime Electronic Dice Kitchen Timer Room Thermometer Daily Reminder Whistle Switch Parking Radar Telephone Switch Noughts and Crosses Enigma and a Weather Vane There is also a MW LW Radio project in the Teach In series 152 pages CD ROM Order code ETI 8 50 CIRCUITS AND DESIGN A BEGINNER S GUIDE TO TTL DIGITAL ICs R A Penfold This book first covers the basics of simple logic circuits in general and then progresses to specific TTL logic integrated circuits The devices covered include gates oscillators timers flip flops dividers and decoder circuits Some practical circuits are used to illustrate the use of TTL devices in the real world Order code 2 5 45 PRACTICAL ELECTRONICS CALCULATIONS AND FORMULAE F A Wilson C G LA C Eng F LE E Bridges the gap between complicated technical theory and cut and tried methods which may bring success in design but leave the experimenter unfulfilled A strong practical bias tedious and higher mathematics have been avoided where possible and many tables have been included The book is divided into six basic sections Units and Constants Direct Current Circuits Passive Components Alternating Current Circuits Networks and Theorems Measurements Order code 5 5 49 MICROCONTROLLER COOKBOOK Mike James The practical solutions to real problems shown in this cookbook pr
127. gnals on the pot wipers are then fed directly to the power amplifier inputs Fig 3 shows the circuit while Fig 4 shows the wiring diagram External preamp If you intend using an external preamplifier you can omit the volume control altogether and simply run the audio input leads direct to the class A power amplifiers What about all those blank holes on the front panel Easy just mount the necessary parts to fill in the holes but don t wire them up The LEDs can be secured at the rear using epoxy RIGHT CHANNEL INPUT SOCKET TO RIGHT POWER AMP INPUT Fig 3 this circuit shows how to use a dual 10kQ log pot as the volume control Fig 4 follow this diagram to wire the volume pot in place FROM RIGHT INPUT SOCKET TO RIGHT POWER AMP FROM LEFT INPUT TO LEFT POWER 10kQ GANGED VOLUME CONTROL POTENTIOMETERS resin female spade connectors should all be tightly crimped the con nectors must be fully insulat ed and there must be no wire strands outside these connectors In addition all spade connectors should be a tight fit onto their lugs especially at the IEC socket the mains switch and the bridge recti fier Re tension any connectors that slide on too easily 2 Check that BR1 s positive and nega tive terminals connect to the correct terminals on the power supply board 3 Check that all the electrolytic capacitors on the power supply board a
128. hey will not short against each other That done install the 7 segment LED displays with the decimal points at the lower right hand side of each display Next install the two 1nF capacitors and the two electrolytic capacitors The latter both lie on their sides see photo and must be oriented as shown the 220uF capacitor lies adjacent to the 10 way IDC connector Now install all the LEDs taking care to orient these correctly These all sit flush against the PC board We used green LEDs for all except the red line LEDs and the shift light LED Note that you can use any number of red LEDs for the red line from 0 10 it s your choice The LDR should be installed at the same height as the LEDs IC1 and IC2 are installed on the rear ofthe PC board Before installing them make sure that the displays have been soldered in correctly and that there are no shorts between pads Now place the ICs in position and solder each pin us ing a fine tipped soldering iron The next job is to make up an IDC lead using a 10 way IDC insulation displacement connector and the key ed IDC socket see Fig 7 The cable is inserted into the IDC which is then squeezed together using a vice or clamp Install the transition connector on the display PC board That s all for this month In Part 2 we ll finish the construction describe thetest and set up procedures and give some hints on installation EPE Everyday Practical Electronics Februa
129. ia k in the formula 56 transconductance characteristics from Fairchild Semiconductor datasheet BS170 Rev C INDUCTIVE COMPONENTS tending to decrease I as temperature increases and threshold voltage tending to increase it The threshold voltage variation has a stronger effect at lower values of Views and mobility variation dominates at larger values of Vos Hence we see the I curves move from positive to negative temperature coefficient as V 1 increased Thus thermal instability in parallel MOSFETS is possible in situations where they are operated at low values of V above This is probably not a common problem but could happen for example if an over rated power MOSFET was used so that relatively low V values were required for the currents in the circuit A paper by Alfio Consoli et al in 2000 argued that trends in efficient power MOSFET design made this problem more likely The issue is also discussed in a 2005 application note AND8199 by Alan Bell from ON Semiconductor onsemi com BJTs have a positive temperature coefficient of the collector current for a given input unlike the drain current for a MOSET this occurs over the full operating range For any set of parallel transistors they will all be slightly different so one will inevitably take a little more current than the others This one will get hotter causing POINT OF INFLECTION INCREASING TEMPERATURE Fig 7
130. ice The coupon must be used in conjunction with all other terms and conditions specified by Microchip Technology Inc MICROCHIP www microchip com The Microchip name logo PIC and MPLAB are registered trademarks of Microchip Technology Incorporated in the USA and other countries All other trademarks and registered trademarks are the property of their respective owners Microchip Technology Inc All rights reserved ME216 Eng 09 08 Constructional 9 11 610 ZZV Power Suppiy Want regulated voltage that can be adjusted to suit your application This Adjustable Power Supply is small easy to build and can be adapted to produce a fully regulated voltage ranging from 1 3V to 22V at currents up to 1A By JOHN CLARKE HERE are many fixed voltage IC regulators available and these can be had with 5V 6V 8V 9V 12V and 15V outputs But what if you want a voltage output that does not fit into one of the standard ranges or if you want to be able to easily adjust this output voltage An adjustable regulator is the answer one that can be set to provide the exact voltage you require This Adjustable Power Supply comprises a small PC board that utilises a 3 terminal voltage regula tor It does not have too many other components in fact there are just three diodes three capacitors a re sistor and a trimpot to set the output voltage from the regulator Circuit details The full circu
131. ign rules Interactive design rule checking Fully configurable bill of materials Polygonal and split power planes Large component libraries for both RS274X Excellon and ODB simulation and PCB layout database export Mixed mode SPICE circuit simulation 3D Viewer with 3DS NL Co simulation of PIC AVR 8051 and and DXF export 22 microcontroller firmware P EFTE E i P 73 pr xL 2 JN PI ds Professional schematic capture Publication quality schematics Automatic component placement TAL 2H gateswap optimization P ET i Prices start from just 150 visit our website for full details or to download a free demo abcenter E E Labcenter Electronics Ltd 53 55 Main Street Grassington North Yorks BD23 5AA Registered in England 4692454 Tel 44 0 1756 753440 Email info labcenter com exc VAT amp delivery www liabcenter com
132. ill not clear Instead of posing the simple questions What kind of dish should I have installed if I want to use a Freesat recorder Freesat s the other a revival web site FAQ asks the question How many cables will I need from my satellite dish to connect to Freesat This is likely to confuse because Sky dishes with quad LNBs use what looks like a single cable made from four bonded strands Freesat says we try and provide clear information to consumers on our website without confusing them with lots of technical detail MD Emma Scott puts the price for a dual LNB installation at 120 instead of the usual 80 and claims 40 of customers are up sold to a dual LNB Freesat is confident that no consumers have been disadvantaged because its call centre staff were explicitly briefed to explain recorder installation Freesat asks if we have heard anything from consumers to the contrary As no dual tuner recorders have yet been sold no viewers have yet had the chance to find out they cannot record one channel while viewing another Blast from the past Twenty years ago Sir Clive Sinclair s devices were fine for hobbyists but Apricot was the Great British Hope for home office computing Apricots were designed to compete with pre Mac Apples and the IBM PC The first models had two 3 5 inch floppy drives and were beautifully styled But they were infuriatingly not fully IBM compatible The disc f
133. imming control is included Serial data is fed in at pin 22 of each IC and the clock signal is fed into pin 21 The serial data comes from the microcontroller IC3 on the control board and this selects which LEDs are to be lit and which are not IC1 and IC2 are run at 5V at pins 1 and 20 while the LEDs have their own adjustable high current supply Pin 19 BRC is the brightness control input It requires 750 to fully drive the LEDs lower current reduces the LED brightness A 1nF capacitor at each pin prevents oscillations We have provided separate dimming control for each IC so that they can be adjusted to provide the same apparent brightness The light dependent resis tor LDR1 controls the brightness Power There are two power supply circuits one to provide 5V for the ICs and the above mentioned LED supply which operates in switch mode to minimise heat dissipation It comprises IC4 transistor Q1 and inductor L1 see the circuit diagram in Fig 3 IC4 is an MC34063 DC DC con verter which runs at around 40kHz to switch transistor Q1 on and off Each time Q1 switches on current builds through L1 until it reaches a peak of about 3A as detected by the voltage drop across the 0 10 5W re sistor between pin 6 and 7 When the current reaches 3A Q1 switches off and the charge within L1 is allowed to continue to flow via diode D2 The resulting supply is filtered with a 470 low ESR capacitor Voltage feedback
134. in these articles so the hardware and its construction is very much down to you Do remember however that you must not attempt to use this circuit to switch mains voltages unless you know exactly what you are doing and understand how to build safe high voltage circuits If in doubt stick with controlling low voltage circuits The author for example has used this circuit to control the on off button on his computer motherboard That carries its own risks but none of them are potentially fatal Before we go through the changes required to the software and web pages we have to work out how to get the existing design from last month to be accessible on the Internet rather than simply connected to your PC locally To do that we need to understand how the PC connects to the Internet and how other computers can or if we wish cannot connect back to us Internet connection For most of us using a home broadband Internet connection the physical interface out of the house is through either the BT telephone wires or a coaxial cable wire Either way the wire is connected to a modem somewhere in your house Some modems provide one or more Ethernet ports for computers to connect articles because you have no easy way to connect your own designed hardware onto the Internet Alternatively go buy yourself a proper modem they can be purchased for around 20 to 30 Routers The job of the router is often two fo
135. ion job done and no elec tronics required Steve Dellow Warwick Everyday Practical Electronics February 2009 ELECTRO NICS LTD 135 Hunter Street Burton on Trent Staffs DE14 2ST Tel 44 0 1283 565435 Chips Parts amp Kits for EPE Projects Programmed PICs and chips for most EPE projects Check our website or phone for prices We have supplied kits for EPE projects for almost 30 years amp Everyday Electronics Top Kits ICEbreaker P C16F877 in cir cuit emulator Kit 900 34 99 1kV 500V Insulation Tester Inc drilled case Kit 848 32 95 Pipe Descaler High Power with led monitor Kit 868 22 95 All Prices Include VAT Add 3 00 P amp P per order or 7 99 for next Fax 44 0 1283 546932 20W Stereo Amp Wide band Low distor tion 11W channel Stereo 20W Mono True rms Real Power Short Circuit amp Overhe Protected Needs 8 to 18V supply Kit inc all parts amp heatsink for stereo or mono KIT 914 11 90 Latest Technology Stable Reliable high performance Ultrasonic PEsT Scarer ran dom 32k pulses Kit867 19 99 P Metal Detector Micro based design sensitive Kit847 63 95 MAGENTA Bat Detectors Our original famous KIT detector KIT 861 37 99 amp See the new built Mkllb and MKIII on the web day Chqs amp most major cards accepted Mail Order Only www magenta2000 co uk sales magenta2000 co uk Measure T
136. is actually bolted to the aluminium baseplate These thermostats are snap action types and react more slowly than fry pan thermostats to ignore short term temperature spikes As a result their hysteresis is also larger Typically they are suitable for sensing temperatures from about 60 C to 200 C 41 Recycle It Every discarded electric iron has a thermostat mounted inside These snap action thermostats can be used to switch at temperatures from about 60 C to 200 C Because they don t use a remote probe this type of thermostat is useful when the temperature of the general environment needs to be sensed Oil filled heater thermostats as with clothes iron thermostats oil filled heater thermostats are designed to sense the temperature of their environ ment and don t have a sensing probe These thermostats are quite sensitive have a small hysteresis and work at room temperatures making them ideal for activating fans inside electri cal equipment Get your magazine instantly anywhere in the world buy and download from the web TAKE A LOOK A FREE ISSUE IS AVAILABLE A one year subscription 12 issues costs just 18 99 US Water bed heater thermostats these thermostats use a remote bulb allowing temperature sensing at a point remote from the thermostat itself They can be set very precisely over the 25 C to 50 C range are quite sensitive and have a small hysteresis However the bulb may
137. is made of video presentations showing soldering and construction techniques The second section contains a set of ten projects for students to build ranging from simple sensor circuits through to power amplifiers A shareware version of Matrix s CADPACK schematic capture circuit simulation and p c b design software is included The projects on the CD ROM are Logic Probe Light Heat and Moisture Sensor NE555 Timer Egg Timer Dice Machine Bike Alarm Stereo Mixer Power Amplifier Sound Activated Switch Reaction Tester Full parts lists schematics and p c b layouts are included on the CD ROM Electronics Circuits amp Components V2 0 provides an introduction to the principles and application of the most common types of electronic components and shows how they are used to form complete circuits The virtual laboratories worked examples and pre designed circuits allow students to learn experiment and check their understanding Version 2 has been considerably expanded in almost every area following a review of major syllabuses GCSE GNVQ A level and HNC It also contains both European and American circuit symbols Sections include Fundamentals units and multiples electricity electric circuits alternating circuits Passive Components resistors capacitors inductors transformers Semiconductors diodes transistors amps logic gates Passive Circuits Active Circuits The Parts Gallery will help students to recognise common elec
138. it diagram for the Adjustable Regulated Power Supply is shown in Fig 1 REG1 is an LM317T 1 5A adjustable voltage regulator that provides a nominal 1 25V between its OUT and ADJ adjust terminals We say it is a nominal 1 25V because depending on the device it can be anywhere between 1 2V and 1 3V This doesn t really matter though because we can adjust the output voltage to the required level using the trimpot Note if you do want a regulator that provides a better tolerance for the 1 25V reference then you could use an LD1117V instead This has a 1 238 1 262V range However do not 20 apply more than 15V to the input of this regulator Output voltage The output voltage from REG1 is set by the 1100 resistor R1 between the OUT and ADJ terminals and by the re sistance between the ADJ terminal and ground This works as follows By using a 110Q resistor and as suming an exact 1 25V reference the current flow is set at 11 36mA This is calculated by dividing the voltage between the OUT and ADJ terminals 1 25V by the 1100 resistor This current also flows through trimpot VR1 1 PC board code 698 available from the EPE PCB Service size 35 38mm 1 LM317T adjustable 3 terminal voltage regulator REG1 1N4004 1 diodes 01 03 2 100mF 25V PC electrolytic capacitors C1 C3 1 10mF 25V PC electrolytic capacitor C2 1 110W 0 25W 196 resistor R1 1 2kW horizontal trimpot VR1 4 PC
139. ject Reproduced by arrangement with SILICON CHIP magazine 2009 www siliconchip com au REGULATED OUTPUT C3 100uF see text ADJUSTABLE POWER SUPPLY i Fig 1 the circuit is based on an LM317T adjustable voltage regulator D1 provides reverse polarity protection while VR1 sets the output voltage SILICONE SEE TEXT Fig 2 here s how to install the parts on the PC board flow through REG1 which could cause damage Diode D3 is also included to pro tect REG1 It does this by clamping the voltage between the ADJ terminal and the OUT and IN terminals in the event that one of the latter is shorted to ground 0V Finally capacitors C1 and C2 reduce ripple by bypassing the IN input and ADJ terminals respectively Capacitor C3 prevents regulator oscillation by swamping any low value capacitance that may be connected to this output Construction All parts for the Adjustable Power Supply are mounted on a PC board code 698 measuring just 35x38mm This board is available from the EPE PCB Service The circuit board com ponent layout is shown in Fig 2 and the PCB copper foil master in Fig 4 As usual begin construction by checking M3 NUTS PC BOARD HEATSINK 15mm LONG m 15mm LONG M3 NYLON M3 MACHINE SCREW SCREW Fig 3 regulator REG1 can be mounted underneath the PC board and attached to a heatsink as shown here Note that its metal tab must be isolated from the heatsink using a TO 22
140. k diodes Only a very small leakage current can therefore flow from drain to source or vice versa Appling a positive voltage to the gate creates a conducting channel under the gate due to the redistribution of charge within the device This process is related to the operation of a diode MOSFET regions The N and P regions in the MOSFET refer to the type of chemical used to dope pure silicon to create useful device behaviour N type silicon has more electrons free to take place in conduction than in pure silicon These free to move electrons are referred to as charge carriers it is the availability of free charge carriers which determines how well a material conducts electricity P type has fewer electrons but these gaps can be regarded as mobile holes which act like positive charge carriers Thus both P and N type silicon conduct electricity reasonably well and increasing the dopant concentration increases conductivity Placing an N region next to a P region creates a PN junction also known as a diode With nothing connected to a diode free charge carriers electrons in the N region and holes in the P move by diffusion across the junction The holes and electrons recombine after which they are no longer available as charge carriers This creates a depletion region around the PN junctions The movement of charge carriers to create the depletion region leaves behind fixed charges on the atoms in the depletion region
141. ke 7 segment displays motor controllers and l c d s The use of macros allows you to control these devices without getting bogged down in understanding the programming Flowcode produces MPASM code which is compatible with virtually all PlCmicro programmers When used in conjunction with the Version 3 development board this provides a seamless solution that allows you to program chips in minutes e Requires no programming experience e Allows complex PlCmicro applications to be designed quickly e Uses international standard flow chart symbols e Full on screen simulation allows debugging and speeds up the development process e Facilitates learning via a full suite of demonstration tutorials e Produces ASM code for a range of 18 28 and 40 pin devices e New features in Version 3 include 16 bit arithmetic strings and string manipulation improved graphical user interface and printing support for 18 series devices pulse width modulation 2 new ADC component etc The Hobbyist Student version is limited to 4K of code 8K on 18F devices oe be int es bore eid Peel ar Hobbyist Student a a a eco Eus 44 inc VAT Institutional Schools HE FE Industry 99 plus VAT Institutional Professional 10 user Network Licence 300 plus VAT SILC 599 plus VAT Flowcode 10 user Network Licence 350 plus VAT Flowcode 50 user Network Licence 699 plus V
142. ker protector module if this hasn t already been done To do this apply power and check that the relay turns on after about five to seven seconds If it does temporar ily short the temperature switch input the relay should immediately switch off Similarly the relay should immedi ately switch offif you disconnect one of the leads to the AC Sense input Now check that the relay switches off if a DC voltage is applied to the loudspeaker terminals this simulates an amplifier fault condition This is done by connecting either a 3V 6V or 9V battery either way around be tween the LSPKIN terminal and the ground terminal of CON1 The relay should immediately switch off Repeat this test for the RSPKIN ter minal then reverse the battery polarity and do these two test again The relay should switch off each time the battery is connected see also pages 26 and 27 Everyday Practical Electronics February 2009 Constructional Project This close up view shows the mounting details for the preamplifier module Note that it is mounted on three 25mm spacers only two at the back and one at the front near the power LED The other end of the board is supported at the front by securing the pot shaft to the front sub panel installing a spacer here would stress the pot connections Dec 08 Note you need at least 3V test battery to bias on the transistors in the DC detection circuit STEP 16 switch off and reconnect the lo
143. l since the early 1990s Thorium is naturally occurring slightly radioactive metal found in small amounts in most rocks and soils Up to now it has been used in light bulb elements lantern mantles arc light lamps welding electrodes and heat resistant ceramics Glass containing thorium oxide has a high refractive index and dispersion and is used in high quality lenses for cameras and scientific instruments Thorium certainly has potential although any gains will be hard won The World Nuclear Association concedes Much development work is still required before the thorium fuel cycle can be commercialised and the effort required seems unlikely while or where abundant uranium is available Shame Everyday Practical Electronics February 2009 Constructional Project 4 F 1 A 2 wae A By GREG SWAIN chassis assembly wiring and adjustment detalls 24 Everyday Practical Electronics February 2009 In this final article we show you how to build a high performance 20W Class A Stereo Amplifier using the modules described over the last few months N the Oct 08 and Nov 08 issues we published the circuit and as sembly details for our new high per formance 20W Class A Stereo Power Amplifier modules along with a suitable Power Supply module Then in the Dec 08 issue we described a Speaker Protection amp Muting module and followed that up in Jan 09 with a Low Noise Preamplifi
144. lability before ordering or calling Prices plus carriage and VAT 35 Recycle It A voltmeter for almost nothing Want a really cheap voltmeter Here s how to adapt a VU meter that s been scrounged from an old audio cassette deck ECENTLY in this column we ve covered both a very cheap lead acid battery charger made from a plugpack and a resistor and a variable output switchmode 12V power supply made from a phone charger Voltmeter In both cases it s useful to also have a meter displaying voltage In the case of the battery charger a voltmeter lets you monitor the battery s voltage as it charges while in the power supply it lets you monitor the output voltage There s a heap of other uses for a voltmeter as well especially when you realise that this meter will cost you next to nothing And it s easy to customise the scale and the voltage range over which the meter works Want some more possible uses Well in a model railway layout you could use the meter to display the voltage being fed to the lighting but instead of having volts marked on the 100kQ MULTI TURN TRIMPOT Fig 1 a VU meter is a very sensitive instrument It can be adapted to measure a wide variety of voltages by installing a 100kQ variable resistor potentiometer in series with the supply voltage This allows you to easily adjust the full scale deflection FSD to match the peak voltage you need to measur
145. lb This comprises a small copper cylinder usually about as big as a short pen cil which is connected to the main switch mechanism by small bore copper tube The tube and the bulb are filled with a liquid or gas that expands as it gets warm and the resulting fluid pressure activates the switch Common consumer goods in which bimetallic strip thermostats are used include oil filled electric space heat ers electric frying pans and clothes irons Remote bulb thermostats are Electric frying pan thermostats use a stainless steel probe that can be inserted through the wall of a pipe or into liquids They can be adjusted to trip at temperatures from about 40 C to 200 C Everyday Practical Electronics February 2009 GND Fig 1 most thermostats are normally closed designs ie they open when the set point temperature is reached But by using a double throw relay it s possible to turn on something when the thermostat opens as shown here This circuit shows how to switch on a 12V DC fan at temperatures above the thermostat set point THERMOSTAT GND Fig 2 when a relay is used adding LEDs to show the operat ing status of the thermostat is easy In this case LED1 lights when the fan is off while LED2 lights when the fan is on used in old electric water bed heat ers Table 1 shows the characteristics of each of these types Selecting a thermostat Scrounge a few of the abovemen tioned consumer items eg d
146. ld First it provides a means of connecting several computers simultaneously to the Internet Second it provides for a private local network You can share network printers and files locally without giving the outside world access In many cases this is a necessity your internet service provider or ISP typically assigns you a single IP address for accessing the Internet Each computer must have its own unique IP address so clearly you cannot have several computers sharing the same one With a router each computer can have its own locally unique and private IP address and the router provides a means of multiplexing each computer onto the Internet IP networking is a complex subject but we only need to know a small amount to be able to get by and put our embedded webserver onto the Internet So let s start by having a look at how a typical computer is configured Command Prompt iy Mindows Configuration ir re Mike Hibbett f ABEL Assuming your computer is currently connected to the Internet open up a command shell on your PC select Start then Run type in and then click OK Type in the command ipconfig then the command route print You should see something similar to Fig 1 The ipconfig command displays the IP address or addresses assigned to your PC s network ports In our example the wireless interface has an IP address of 192
147. ll this column is for you And it s also for people without a lot of dough Each month we ll use bits and pieces sourced from discards sometimes in mini projects and other times as an ideas smorgasbord And you can contribute as well If you have a use for specific parts which can easily be salvaged from goods com monly being thrown away we d love to hear from you Perhaps you use the pressure switch from a washing ma chine to control a pump Or maybe you salvage the high quality bearings from VCR heads Or perhaps you ve found how the guts of a cassette player can be easily turned into a metal detector Well we made the last one up but you get the idea If you have some practical ideas write in and tell us the difference between the switch on and switch off temperatures is fairly small and they react quite quickly to temperature changes Both snap action and slow mov ing thermostats are used in frying pans with later models more likely to be the snap action type It s very easy to tell if you re salvaging a snap action thermostat hold the control box up to your ear as you slowly turn the knob If you hear a satisfying click you know you re got a snap action type Clothes iron thermostats clothes irons also use bi metallic thermostats Despite being controlled by a knob or lever placed on top of the iron the thermostat is mounted deep in side the iron In fact one end of the bimetallic strip
148. ll 8 to 40 pin serial mode AND parallel mode PIC15C family PIC microcontrol lers Free Windows soft ware Blank chip auto detect for super fast bulk programming Optional ZIF socket Assembled Order Code AS3117 24 95 Assembled with ZIF socket Order Code AS3117ZIF 39 95 ATMEL 89xxxx Programmer ai Uses serial port and any standard terminal comms program 4 LED s display the status ZIF sockets not included Supply 16Vdc Kit Order Code 3123KT 24 95 Assembled Order Code AS3123 34 95 Introduction to PIC Programming Go from complete beginner to burning a PIC and writing code in no time Includes 49 page step by step PDF Tutorial Manual Program ming Hardware with LED test section Win 3 11 XP Programming Software Program Read Verify amp Erase and 1rewritable PIC16F84A that you can use with different code 4 detailed examples pro vided for you to learn from PC parallel port Kit Order Code 3081KT 16 95 Assembled Order Code AS3081 24 95 871 Credit Card Sales PIC Programmer Board Low cost PIC programmer board supporting a wide 4 range of Microchip PIC microcontrollers Requires PC serial port Windows interface Kit Order Code VK8076KT 21 95 PIC Programmer amp Experimenter Board The PIC Programmer amp Experimenter Board with test buttons and LED indi cators to carry out educa tional experiments such as the supplied programming ex
149. ltage differential probes a passive 500 2 scope probe set of 5062 coaxial attenuators and a 50 2 coaxial terminator The new high voltage differential probes give a choice of bandwidths from 70 to 100MHz and have differential measuring ranges from 700V to 7kV They are suitable for measurements on mains circuits motors and switch mode power supplies especially in applications where voltages are not referenced to ground The new 500MHz passive scope probe is perfect for general purpose use with 10 1 attenuation and an input impedance of IMQ It has adjustable low frequency and high frequency compensation and is compatible with all major brands of oscilloscope The cable length is 1 5 metres The new BNC attenuator set allows you to increase the input range of your scope or reduce the output level of a fixed amplitude signal source The BNC feed through terminator is useful for connecting signals from a low impedance source Alan Tong MD of Pico Technology commented With our 16 years of experience in PC oscilloscopes we know how difficult it can be to find good quality probes and accessories for your scope Now we can save you time and money by supplying all the scope accessories that you need The prices are 042 100MHz 1400V CAT III differential probe 330 043 100MHz 700V CAT III differential probe 450 TA044 70MHz 7kV CAT I differential probe 480 049 500MHz passive 10 1 probe 45 TA050 3 6
150. ly the gate and drain to the P type region just under the gate If sufficient electrons accumulate here there will eventually be an excess of electrons so the area just under the gate will behave as if it is N type silicon This processes 1s known as inversion because the type of semiconductor has been inverted P to N or N to P by the applied voltage Having created an N type inversion region under the gate Fig 3 we now have an N N N path from source to drain rather than the N P N back to back diodes previously described The conducting region under the gate is called the channel Conduction can now take place from source to drain The transistor is on and the gate source voltage at which this occurs is called the threshold voltage Inversion does not occur instantly at one gate voltage but actually takes place over a range of voltages thus we can have weak inversion through to strong inversion at or above the threshold voltage Traditional circuit design uses the MOSFET in strong inversion but more recently very low power circuit design techniques using weak inver sion have been developed The formation of depletion layers and channel inversion involves the availability of charge carriers and their distribution in the semiconductor Distribution of charge produces potential like the potential SOURCE SOURCE DRAIN SOURCE CURRENT barrier in a diode In the case of a MOSFET a key quantity 15 the surface X
151. m a junked consumer item Whether you need to switch at room tempera ture or 200 C the thermostat doesn t have to cost you a cent How they work A thermostat is basically an adjust able temperature switch Nearly all thermostats that you can salvage work in a similar way A special piece of metal called a bi metallic strip is the basis of the You could pay lots for a professional looking thermostat like this or instead use a salvaged frying pan thermostat and a handful of other components to make your own for nearly nothing 40 design As its name suggests this strip is actually two different metals joined together These two metals have different expansion rates so as they are heated one gets longer faster than the other This causes the strip to bend When it has bent far enough ie it s hot enough it breaks the connec tion between two electrical contacts turning off the circuit The switch ing temperature is varied by using a threaded rod to vary the distance between the electrical contacts and the bimetallic strip As you can imagine in this type of design the electrical contacts open and close very slowly In certain ap plications this could cause arcing so many thermostat designs use a snap action approach where a small leaf spring causes the contacts to quickly snap open or snap closed once the trip point has been reached Another type of thermostat uses a remotely mounted bu
152. maxi mum voltage is towards the end of the scale After you ve setthis don t touch the trimpot again Next alter the input voltage mea sure it with the multimeter and work out what each ofthe other graduations on the modified meter scale should show Be sureto round offthe voltages to the nearest whole volt For example on one of the meters shown here the scale goes 4 7 11 14 18 25 34V Once you ve figured it all out use your graphics software to put the numbers on the scale along with any other writing you want Finally print it out on gloss paper cut it to shape and stick it in place Using it Using the meter is as simple as connecting it and its series 100 trimpot across the voltage source that you want to monitor Note that if the Fig 2 wiring a 10k pot across a plugpack provides a variable voltage source allowing you to calibrate the scale The multimeter shows what the readings on the new meter scale should be Everyday Practical Electronics February 2009 meter needs to be used at night it s easy to illuminate the scale In fact the cassette deck that you scrounged the meter from probably also had a suitable bulb in it Make sure that it has the correct voltage rating for your application though EPE Reproduced by arrangement with SILICON CHIP magazine 2009 www siliconchip com au ANGRE S XGAMESTATION LEARN STEP HOw TO DESIGN AND BULO YOUR DW
153. most advanced training centres Easy access to customers throughout the UK and Europe and a comprehensive programme of workshops and seminars will allow customers to enhance their skills in embedded solutions RF and analogue design The training centre will also enhance our opportunity to engage in a two way dialogue with our customers which will help to shape the development of future Microchip products The new building will integrate innovative features designed to reduce carbon emissions to levels which are around 50 lower than conventional buildings These features include a heat recovery system to recycle warm air peripheral infra red lighting and access to a bore hole to provide a sustainable source of water for heating and cooling Navigation with a rear view The Travel Liberty 7 is Sevic s brand new GPS navigation device with a 4 3 inch TFT touch screen as well as a rear view camera The device features GPS navigation 4 3 inch TFT touchscreen 2D 3D map depiction day and night mode voice guidance points of interest POIs intelligent destination search warning signal if you exceed the speed limit zoom function zoom in zoom out favourites prepared for TMC optional accessory not available for all countries European maps Teleatlas Bluetooth camera The Teleatlas European map including POIs is pre installed onto the provided 2GB SD card An intelligent destination search makes using the pil
154. mount nsu ated RCA phono sockets red and black 2 2 way loudspeaker terminal panels 1 pot nut and washer 5 P clamps 20 M3 x 6mm screws 20 M3 shakeproof washers 20 M3 flat washers 13 M4 x 10mm screws 1 M4 x 16mm screw to secure bridge rectifier BR1 22 M4 flat washers 1 M4 shakeproof washer for bridge rectifier BR1 Heatsink compound for BR1 Modules 1 right channel class A power amplifier module Altronics K 5126 1 left channel class A power amplifier module Altronics K 5127 1 power supply module Altronics K 5128 1 preamp and remote volume control module Altronics K 5129 1 loudspeaker protector module Altronics K 5124 Wire cable miscellaneous 1m brown 32 0 20 extra heavy duty hook up wire mains rated 2m red 32 0 20 extra heavy duty hook up wire 1m black 32 0 20 extra heavy duty hook up wire 2m green 32 0 20 extra heavy duty hook up wire mains rated 250mm 24 0 20 heavy duty blue hook up wire 1m figure 8 shielded audio cable 1m heavy duty 90 0 18 speaker cable 40 small nylon cable ties 7 adhesive cable tie mounts 500mm of 10mm diameter heatshrink tubing Finally do the nut up firmly but don t over tighten it otherwise you ll distort the metal chassis Note Fig 1 shows both the trans former and the preamplifier module offset to the right compared to their true locations in the chassis This has been necessary to keep these parts clear of the magazine centre As previously mentione
155. n important classes of filter filter order filter impedance and impedance matching and effects of different filter types Advanced Theory which covers the use of filter tables mathematics behind filter design and an explanation of the design of active filters Passive Filter Design which includes an expert system and filter synthesis tool for the design of low pass high pass band pass and band stop Bessel Butterworth and Chebyshev ladder filters Active Filter Design which includes an expert system and filter synthesis tool for the design of low pass high pass band pass and band stop Bessel Butterworth and Chebyshev op amp filters ROBOTICS amp MECHATRONICS Case study of the Milford Instruments Spider Robotics and Mechatronics is designed to enable hobbyists students with little previous experience of electronics to design and build electromechanical systems The CD ROM deals with all aspects of robotics from the control systems used the transducers available motors actuators the circuits to drive them Case study material including the NASA Mars Rover the Milford Spider and the Furby is used to show how practical robotic systems are designed The result is a highly stimulating resource that will make learning and building robotics and mechatronic systems easier The Institutional versions have additional worksheets and multiple choice questions e Interactive Virtual Laboratories e Little previous
156. n 1 39 95 amp 300 in 1 59 95 details on website Tools amp Test Equipment We stock an extensive range of soldering inverters amp much more please visit web site to see our full range of products tools test equipment power LM Two Channel USB Pc Oscilloscope This digital storage oscillo scope uses the power of your PC to visualize electrical sig nals Its high sensitive display resolution down to 0 15mV combined with a high band width and a sampling fre quency of up to 1GHz are giving this unit all the power you need Order Code VPCSU1000 289 95 Personal Scope 10MS s The Personal Scope is not a graphical multimeter but a com plete portable oscilloscope at the size and the cost of a good mul timeter Its high sensitivity down to 0 1mV div and extended scope functions make this unit ideal for hobby service automo 754 tive and development purposes Because of its exceptional value for money the Personal Scope is well suited for educational use Order Code VHPS10 429795 119 95 See website for more super deals www QuasarElectronics com securo Online ore recs e Full Listing amp Photos e Kit amp Software Poin Everyday Practical Electronics Magazine has been publishing a series of popular kits by the acclaimed Silicon Chip Magazine Australia These projects are bullet proof and already tested down under All Jaycar kits
157. n eternity tethered to a PC and broadband I decided that the time was ripe to try handling email on the move It has taken over four months for my new but already discontinued HTC Tytn II mobile phone to settle into a usable state The phone runs Windows Mobile 6 1 and includes mobile versions of Internet Explorer Microsoft Word Excel Notes Adobe Reader and more It is a powerful multitasking device and its PDA style has a slide out mini QWERTY keyboard and touch sensitive display The jury is still out on the need for a stylus though My HTC II uses the Orange network and has built in WiFi so it is very good for keeping on top of emails at home as it relieves me of the chore of firing up a laptop At other times GPRS handles email and data at which time an extremely close eye must be kept on tariffs to avoid incurring eye watering running costs 30 000 to fetch a movie as one user found to their dismay If you want to get the best out of your phone then it s wise to check out what others are saying online There is bound to be a forum dedicated to your phone and this can be a lifesaver For example www xda developers com is dedicated to the HTC product line Www modaco com cov ers Windows Mobile and Pocket PC phones and www blackberryforums com is there to lend a hand with Blackberry phones These forums offer practical tips and pointers to useful software patches or updates If you can t find your particul
158. n hits the internal collar 3 Crimp the connection using the crimping tool 4 Check that the connection is secure and properly insulated with no wire strands outside the connector this is particularly im portant for the 230V AC wiring The leads at the other end of each cable are also later fitted with spade connectors after they have been run Everyday Practical Electronics February 2009 to their destinations and cut to the correct length It s best to install the low voltage DC wiring first This can go in as follows 1 Install the supply wiring to the two power amplifiers These cables should be run using extra heavy duty red green and black leads Twist the leads together and initially fit spade connectors to the power supply ends only That done plug each cable into the power supply board and route it to its respective power amplifier board When it reaches the amplifier board cut the green lead to length fit it with a spade connector and plug it in The red and black leads then continue under the amplifier to the centre of the board They then diverge at right 29 Constructional Project One essential item that s required to build this amplifier is a ratchet driven crimping tool necessary for crimping the insulated quick connect terminals to the leads Don t even think of using one of the cheap non ratchet crimpers that typicall
159. ng in Now I have discovered that the account I created has been deleted In this regard I have gone through my spam filters with a fine toothed comb and to date have not received a confirmation email either way This might sound a little bit crazy but I am beginning to suspect that there is a problem with communications between South Africa and the UK as I am not able to contact or illicit a response from any one of your advertisers in your magazine Magenta Electronics is a prime example I have now given up trying to email them as they do not respond leading me to 79 kindly will be think that email communications from my country has been blacklisted by major UK ISPs It is indeed possible to do this especially in Linux based machines that run Spamassassin it takes one line of code to block an entire country I can really understand that this country of mine quite frankly has an appalling reputation and is indeed the crime capital of the world including cyber crime and that this place is a spammers paradise but I am quite perturbed that lately only a handful of my emails to the UK reach their recipients and it seems coincidentally that those who do get my mail have their sites and accounts hosted outside the UK This situation is new to me in the past I ve dealt with Greenweld and I ve been a longtime customer of Bull Electrical I am still receiving their catalogue in the mail each year 0 that
160. ng of bipolar steppers and direction control Synchroniseable when using multiple drivers Perfect for desktop CNC applications Kit Order Code 3187KT 29 95 Assembled Order Code AS3187 39 95 Shaking Dice This electronic construction kit is great fun to build and play with Simply shake and watch it slowly roll to stop on a random number j Kit Order Code VMK150KT 9 95 Running MicroBug This electronic construc tion kit is an attractive bright coloured bug shaped miniature robot The microbug is always hungry for light and travels toward it Kit Order Code VMK127KT 9 95 Video Signal Cleaner Digitally cleans the video signal and removes un wanted distortion in video signal In addition it stabi lises picture quality and luminance fluctuations You will also benefit from improved picture quality on LCD monitors or projectors Kit Order Code VK8036KT 19 95 Assembled Order Code VVM106 26 95 PC Interface Board This interface card excels in its simplicity of use and installa tion The card is con nected in a very sim ple way to the printer port there is no need to open up the computer Likewise there is no need to install an extra printer port even if a printer is to be used This can be connected to the card in the usual manner Connection to the computer is optically isolated so that damage to the computer from the card is not possible Kit Order Code VK80
161. nics up to the operation and architecture of microprocessors The virtual laboratories allow users to operate many circuits on screen Covers binary and hexadecimal numbering systems ASCII basic logic gates monostable action and circuits and bistables including JK and D type flip flops Multiple gate circuits equivalent logic functions and specialised logic functions Introduces sequential logic including clocks and clock circuitry counters binary coded decimal and shift registers A D and D A converters traffic light controllers memories and microprocessors architecture bus systems and their arithmetic logic units Sections on Boolean Logic and Venn diagrams displays and chip types have been expanded in Version 2 and new sections include shift registers digital fault finding programmable logic controllers and microcontrollers and microprocessors The Institutional versions now also include several types of assessment for supervisors including worksheets multiple choice tests fault finding exercises and examination questions ANALOGUE FILTERS Analogue Filters is a complete course in designing active and passive filters that makes use of highly interactive virtual laboratories and simulations to explain how filters are designed It is split into five chapters Revision which provides underpinning knowledge required for those who need to design filters Filtrer Basics which is a course in terminology and filter characterizatio
162. nline site is designed with IE7 in mind I agree it sometimes nags users but usually it isn t too onerous and after a while you find the benefits outweigh any drawbacks We have found that every user who had problems using IE6 and 64 audience will get to hear some of the audio spill over If it s difficult to find the correct frequency I can suggest some alloc ations to try there are specifically reserved frequencies Before taking this equipment to his club George should first tune to an ordinary broadcast station and make sure that he can successfully hear that through the intended headphones Good luck hope this helps you to get out and enjoy the club again Godfrey Manning G4GLM via email Thanks for the tips Godfrey any more helpful ideas out there then went on to update their system to IET suffered no further problems An alternative is Firefox which has plenty to offer it s free and will run alongside your IE6 IES is on the way I m sorry this is the best I can offer I hope it doesn t get in the way of your enjoyment of the magazine Alan Winstanley On line Editor d Africa calling or trying 0 I have tried to register for the Chat Zone which I did approximately a month ago I never received an email informing me of the outcome of the decision whether I was accepted or not on the board While I suspect the email may have been lost I kept checking by loggi
163. nt for a digital tachometer It comprises a counter a timer and a digital display DISPLAY LED TACHOMETER ARRANGEMENT Fig 2 the block diagram for the LED Tachometer is more complicated than the basic unit and includes both digital and bargraph LED displays During calibration the red line RPM can be selected as well as the number of red line LEDs The tachometer then automatically calculates the RPM in crements required to light each LED The shift light RPM can also be en tered into the tachometer during the setting up procedure If you do not want the shift light LED to operate you can enter an RPM setting higher than the engine will reach The rev limiter output from the tachometer can be used to prevent the engine from over revving if say you miss a gear However the limiter ac tion is very abrupt and is not suitable for normal speed or RPM restriction The limiter output controls an external cutout circuit that works by killing the ignition or interrupting fuel to the injectors We will discuss these op tions in Part 2 next month Setting up the tachometer is easy because we use the digital display to show the options and the current settings while you set the number of cylinders and other settings using pushbutton switches Basic digital tachometer The basic arrangement for a typical digital tachometer is shown in block diagram Fig 1 It comprises a counter a timer and a digital display For
164. nternal IP address E Public Priv ate Private IP TCP 192 168 62 69 _ 192 168 62 0 When choosing a local IP address for your own PIC webserver device choose one that is close in value to the value assigned to your PC Take the PC s address the four numbers separated by characters and change the last number to a different value in the range of 1 to 254 Update the PIC source code with the new value update your router to point the ISP assigned public address to this value as shown in Fig 2 and when your web server is powered up and connected to the router web page requests made from the Internet to your public IP address will be sent directly to it You can switch your PC off and so long as the router is powered up your webserver will be available 24 hours a day anywhere in the world Next month we will finally complete the practical webserver design and put a globally accessible yet secure appliance switch onto the Internet Everyday Practical Electronics February 2009 59 5 PLEASED TO BE ABLE TO OFFER YOU THESE ELECTRONICS CD ROMS ELECTRONICS PROJECTS 2 ee Electronic Projects is split into two main sections Building Electronic Projects Circuit simulation screen contains comprehensive information about the components tools and techniques used in developing projects from initial concept through to final circuit board production Extensive use
165. o the mounting holes for both PC boards the REG1 and Q1 mounting holes and the cable tie holes for secur ing L1 need to be 3mm in diameter Control board Start with the control PC board you can install the low profile components such as the resistors links and ICs Use rs et s umb am Table 1 to selectthe resistors and check each value with a digital multimeter IC3 is installed in a socket make sure it goes in with the correct orientation The diodes go in next making sure that the orientation of each is correct That done install transistors Q2 and the trimpots and the switches The 10 way IDC plug can then be installed Everyday Practical Electronics February 2009 1 as well as the two 2 way screw termi nal connectors Next install the capacitors but note that the 47nF capacitor top right marked with the asterisk should be left out of the circuit for the moment Both transistor Q1 and the regulator REG1 are mounted horizontally and secured with an M3 screw and nut to 17 Constructional The control board is mounted on pillars in the bottom half of the case and secured using four screws The Mode and set LEDs towards the rear are used during the setting up procedure details next month the PC board Q1 is also mounted on a small heatsink The leads can be bent using pliers before each component is inserted into the PC board holes
166. omponents Power Supplies The Amateur Electronics Workshop The Uses of Semiconductors Digital Electronics Operational Amplifiers Introduction to Physics including practical experiments Semiconductors and Digital Instruments CIRCUITS TO BUILD The Base Manual describes 12 projects including a Theremin and a Simple TENS Unit ESSENTIAL DATA Extensive tables diodes transistors thyristors and triacs digital and linear i c s EXTENSIVE GLOSSARY Should you come across a technical word phrase or abbreviation you re not familiar with simply look up the glossary and you ll find a comprehensive definition in plain English The Manual also covers Safety and provides web links to component and equipment Manufacturers and Suppliers Full contents list available online at www epemag com SUPPLEMENTS Additional CD ROMs each containing approximately 500 pages of additional information on specific areas of electronics are available for 19 95 each Information on the availability and content of each Supplement CD ROM will be sent to you PRESENTATION CD ROM suitable for any modern PC Requires Adobe Acrobat Reader which is included on the CD ROM Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Tel 01202 873872 Fax 01202 874562 PLEASE send me THE MODERN ELECTRONICS MANUAL CD ROM ELECTRONICS SERVICE MANUAL CD ROM enclose payment of 29 95 for one manual or 49 90
167. on t dare to miss this Order code 2 CD ROM GETTING THE MOST FROM YOUR MULTIMETER R A Penfold This book is primarily aimed at beginners and those of limited experience of electronics Chapter 1 covers the basics of analogue and digital multimeters discussing the relative merits and the limitations of the two types In Chapter 2 various methods of component checking are described including tests for transistors thyristors resistors capacitors and diodes Circuit testing is covered in Chapter 3 with subjects such as voltage current and continuity checks being discussed In the main little or no previous knowledge or experience is assumed Using these simple component and circuit testing techniques the reader should be able to confidently tackle servicing of most electronic projects Order code BP239 5 49 Over 1 000 projects Over 800 pages in Adobe Acrobat format 21 95 96 pages OSCILLOSCOPES FIFTH EDITION lan Hickman Oscilloscopes are essential tools for checking circuit operation and diagnosing faults and an enormous range of models are available This handy guide to oscilloscopes is essential reading for anyone who has to use a scope for their work or hobby electronics designers technicians anyone in industry involved in test and measurement electronics enthusiasts lan Hickman s review of all the latest types of scope currently available will prove especially useful for anyone planning to buy or
168. orge Chatley asks in his letter Linux and more Dec 08 about ways to receive from a radio mic so as to overcome his hearing impairment I suggest the easiest way is to tune an ordinary scanner scanning receiver to the radio mic frequency usually this would be FM mode The scanner would then feed headphones that George needs to wear I expect he ll have to turn the volume up high so proper headphones with acoustic cups that cover the ears is in order otherwise those in the nearby Registration and Dear EPE I have been trying to register on the new website but I am not getting very far I click on the Register link and get taken to the Registration page but I cannot enter any details into the text boxes asking for my details such as name and email address The only things that work for me are the country and state selection boxes I know it does say on the homepage and probably on other pages to use IE7 but I am using IE6 because I find IE7 far too over protective and have to click on lots of boxes and stuff just to get to my own home page Please can you let me know where I am going wrong Thanks Mike Brearley via email Alan replied to Mike I don t run the EPE Online site myself but unfortunately I fear you ve answered your own question IE6 dates back to 2001 it s full of security holes and it isn t compatible with more modern standards of web code We do highlight that the EPE O
169. ormatting was slightly different and the screens incompatible Quality control at the factory was poor The power supplies overheated and solder joints opened up The venture collapsed and in 1990 Mitsubishi bought the brand name and then closed the factories Now Apricot is back in a highly competitive market with small laptops that look much like other laptops and are similarly priced Linux versions cost 279 and Windows XP costs 49 extra Says CEO Shahid Sutan My partner Julien Clairet and I have been negotiating for years to buy the trademark We are now bringing the brand back The components of course come from the Far East but the laptops are assembled in the UK GROUND BREAKING Microchip has announced that work has started on building its new European headquarters located in the Winnersh Triangle near Reading The ground breaking ceremony took place on 18 September 2008 and completion of the new building is scheduled for September 2009 Partofa 100 million development scheme for the Winnersh Triangle Microchip s new headquarters will be purpose built to house their European sales and support teams as well as a state of the art regional training centre with extensive training rooms conference suites and laboratories Gary Marsh Microchip s European VP Sales explains Building the new European headquarters to our own specifications gives Microchip the opportunity to create one of the industry s
170. ors Low cost auto motive type crimpers are definitely not suitable here as their use would result in unreliable and unsafe connections particularly where the mains wiring is concerned Everyday Practical Electronics February 2009 Il il aalala This chassis view clearly shows the routing of the loudspeaker cable from the right channel power amplifier It runs along the bottom of the rear panel and is secured using adhesive cable tie mounts and cable ties As shown in the photos all the sup ply leads are tightly twisted together This not only keeps the wiring neat but also minimises hum pick up since the hum fields are effectively cancelled out There s an easy way to twist the leads together and that s by using a hand drill All you have to do is secure one end of the leads in a vice and the other end in the drill chuck You then rotate the drill handle until you get a nice even lead twist along the full length of the cable Tight squeeze Make the twists reasonably tight but don t overdo it the wire will break through the insulation if you do Once it s done trim the ends to remove any damaged insulation and fit spade con nectors to the leads at one end of the cable only The spade connectors are fitted as follows 1 Trim 6mm of insulation from the end of a lead and twist the wire strands together 2 push the lead into the connec tor until the insulatio
171. orset BH22 9AU Printed in England by Apple Web Offset Ltd Warrington WA1 4RW Distributed by Seymour 86 Newman St London W1T Subscriptions INLAND 19 95 6 months 37 90 12 months 70 50 2 years OVERSEAS standard air service 23 00 6 months 44 00 12 months 83 00 2 years Express airmail 32 00 6 months 62 00 12 months 119 00 2 years Payments payable to Everyday Practical Electronics Subs Dept Wimborne Publishing Ltd Email sups epemag wimborne co uk EVERYDAY PRACTICAL ELECTRONICS is sold subject to the following conditions namely that it shall not without the written consent of the Publishers first having been given be lent resold hired out or otherwise disposed of by way of Trade at more than the recommended selling price shown on the cover and that it shall not be lent resold hired out or otherwise disposed of in a mutilated condition or in any unauthorised cover by way of Trade or affixed to or as part of any publication or advertising literary or pictorial matter whatsoever Ye 4 for rectifi n AC supply T 14 25 Audio c 100Wrms 4ohm DC sup ply circuit on board with LED indication ideal for ac tive speaker system or sub woofer guitar amp home theatre systems etc Over load amp short circuit protected K8060 Kit 13 25 Assembled with heatsink 28 75 Audio Amplifier Stereo 2 x 50Wrms or a Mono 100Wrms ampli fie
172. os to install the parts in the chassis and complete the wiring Note that the supply leads to the modules transformer and mains switch are twisted together see photos and text screws themselves and also via direct metal to metal contact between the various sections The transformer mounting bolt must also be earthed This means that you have to remove some of the powder coating from around the mounting hole on the outside of the chassis ie from under the bolt head The same goes for all other mounting screws that go through the bottom of the chassis In particular make sure that you clear away the powder coating from around the six heatsink mounting holes Once you ve done all this remove the front panel wrap it up and put it to one side so that it doesn t get scratched or damaged It doesn t take much of an accident to spoil the panels appearance while you are installing the parts in the chassis and completing the interwiring Installing the hardware You can now start installing the hardware in the case see Fig 1 Be gin by securing the IEC fused power socket to the rear panel using two 6g x 12mm countersink self tappers That done mount the two insulated RCA phono input sockets and the two loudspeaker terminal panels Note that the white left colour coded RCA phono socket goes to the top while the red right socket goes to the bottom The loudspeaker terminal pairs go in with their red positive ter
173. ot VR1 slowly clockwise until the meter reads 1 68V This is equivalent to a quiescent current of 1 12A That done let the amplifier run for about five minutes or so and then check the voltage again During this time the amplifier heatsink will be come quite warm and the quiescent current will drift slightly Readjust to obtain 1 68V again STEP 9 switch off remove the 1 50 5W resistors and install the 3A fuses STEP 10 repeat steps 5 to 8 for the left channel power amplifier module STEP 11 let the amplifiers run for about 30 minutes so that the heatsinks get nice and hot then check the voltage across one of the 0 1Q 5W resistors in the right channel power amplifier Adjust trimpot VR1 for a reading of 112mV Now check the voltage across in the end caps and solder the resistors in place as shown The original fuses can then be removed and the modified fuses clipped into place see photos the other 0 10 resistor these resistors have a tolerance of about 10 so set so that the average voltage across them is 112mV STEP 12 repeat step 11 for the left channel power amplifier STEP 13 switch off and reconnect the preamplifier s 22V OV 22V leads to the power supply module STEP 14 check the preamplifier and remote volume control for correct operation as described in the Jan 09 issue skip this step if you ve already done this STEP 15 check the operation of the loudspea
174. ot incredibly simple It costs 349 00 Euro For more information contact Sevic Systems Luxembourg SA Zone Industrielle Bommelscheuer L 4901 Bascharage Luxembourg Tel 352 0 26 65 65 Email info sevic com Web www sevic com Everyday Practical Electronics February 2009 PEAK EXPANSION Peak Electronic Design has recently expanded their distributor network with the appointment of five new distribution partners Now the famous Peak Atlas range of automatic component identification and measurement tools are easier to get hold of in Australia Holland Germany USA and the UK This is in addition to a worldwide network of established distributors so buying Peak products is faster and easier To assist with the UK Hobbyist market a new UK distribution partner has joined Peak JPR Electronics in Dunstable offer the full range of Peak products as well as many other products aimed at hobbyists education and industry To find your nearest distributor simply visit www peakelec co uk and click on the distributors tab If you can t find a distributor near you then you can of course order from Peak directly West Road House West Road Buxton Derbys 5 7 Tel 01298 70012 Fax 01298 70046 Email sales peakelec co uk and technical peak elec co uk PICO S NEW SCOPE PROBES Pico Technology renowned leaders in PC oscilloscopes has released a new range of oscilloscope accessories including three high vo
175. other parameters too m as the DC 150mm long Fabric Wrist Strap Sealed retail pack Battery included Gold plated croc clips 2 AA Batteries included see description in main offer Uniros Aluminium 6 LED Torch ics Peak Electronic Design Ltd West Road House West Roads edd 2200 pep per erden Pica 29172 UK VAT or 0018995 Everyday Practical Electronics February 2009 Buxton Derbyshire Ska7 6HF 1298 70012 wwwapeakelec conuk sales peakelec co uk 65 Surfing The Internet Net Work Alan Winstanley Mail on the move his month s Net Work column discusses trends in mobile email suggesting an effective anti spam service with more discussion and bonus content available by following the Net Work link on EPE Online One of the unstoppable trends in electronics is the drive towards cramming more technology into a smaller size with lower price breaks and lower power consumption Compare the carrier bag sized immobile phones of the 1980s that could barely make a phone call and needed a battalion of Ni Cad batteries to power them with today s indispensable but ever more disposable cellphones The latest phones use custom lithium ion batteries and apart from SMS text messaging may incorporate email web browsing a digital camera or two a video and MP3 player GPS and Bluetooth all displaying on a bright colour LCD with satnav available as an accessory After spending a
176. oved by myself before the account is opened I physically screen the list and make a decision based on a number of criteria Sometimes I get it wrong and a genuine Chat Zone application is inadvertently disallowed but if the user contacts me afterwards I am more than happy to set up an account immediately If you would like to confirm your choice of username I will open an account with a temporary password Perversely it is true to say that our automated confirmation emails from the Chat Zone server are treated as spam by some ISPs and never reach their intended destination in which case I will personally email the logins from my desktop So please let me know your choice of username and we ll see what happens Thank you for persevering with this and thank you also for your interest in EPE magazine Alan Winstanley On line Editor Linux PICkit 2 serial coms utility WIP Dear EPE I jumped at the chance of a PICkit 2 for a tenner However I was a little disappointed that there was no serial coms tool So now temporarily hacked away at the linux pk2cmd to make a simple tool Since I want the convenience of leaving the PICkit 2 in situ and not have to swap the cable from place to place I have bridged the UART s TX pin RC6 with a diode to RB7 My hack is quite happily putting the PICkit 2 into serial mode and receiving data from the PIC s UART when it s running I haven t done it in the other direction as I
177. ovide the basis to make PIC and 8051 devices really work Capabilities of the variants are examined and ways to enhance these are shown A survey of common interface devices and a description of programming models lead on to a section on development techniques The cookbook offers an introduction that will allow any user novice or experienced to make the most of microcontrollers Order code 26 25 99 142 pages 256 pages 240 pages COMPUTING AND ROBOTICS WINDOWS XP EXPLAINED N Kantaris and P R M Oliver If you want to know what to do next when confronted with Microsofts Windows XP screen then this book is for you It applies to both the Professional and home editions The book was written with the non expert busy person in mind it explains what hardware requirements you need in order to run Windows XP successfully and gives an overview of the Windows XP environment The book explains How to manipulate Windows and how to use the Control Panel to add or change your printer and control your display How to control information using WordPad notepad and paint and how to use the Clipboard facility to transfer information between Windows applications How to be in control of your filing system using Windows Explorer and My Computer How to control printers fonts characters multimedia and images and how to add hardware and software to your system How to configure your system to communicate with the outside world
178. potential particularly at strong inversion at the silicon surface just below the gate Surface potential is dependent on temperature doping level which is why we see a variation of V with temperature in Fig 1 BS170 MOSFET The device Gerry referred to the BS170 1 described as using DMOS technology which uses a different physical structure from Fig 3 to create the MOSFET The approach used in Fig 3 cannot readily be extended to produce high power devices the cross sectional area of the conducting region simply cannot be made big enough to make the on resistance I eto small without using an unreasonably large area of silicon Furthermore the large gate area would make such a device very slow due to the high capacitance of a very large gate In Fig 4 is shown the structure of a basic power MOSFET The channel is still horizontal under the gate but it is much shorter than in the conventional MOSFET and the current flow between channel and drain is vertical The short channel means a low on resistance a property required by power devices The actual structures of real power MOSFETS is more complex than that shown in Fig 4 and a variety of other structures including trenches are used The vertical nature of power MOSFETs means that the transistors can readily be repeated in parallel across a piece of silicon to increase current handling capacity This is only feasible if they share the current e
179. purchased and downloaded for just 18 99US approx 13 per year available from www epemag com TED UK MAGAZINE FORIELECTRONICS TECHNOLOGY amp COMPUTER PROJECTS EED GU PAR 228 5 amp LA Prius cP 4 SUBSCRIPTIONS Subscriptions for delivery direct to any address in the UK 6 months 19 95 12 months 37 90 two years 70 50 Overseas 6 months 23 00 standard air service or 32 00 express airmail 12 months 44 00 standard air service or 62 00 express airmail 24 months 83 00 standard air service or 119 00 express airmail Online subscriptions for downloading the magazine via the Internet 18 99US approx 13 for one year available from www epemag com Cheques or bank drafts in sterling only payable to Everyday Practical Electronics and sent to EPE Subs Dept Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Tel 01202 873872 Fax 01202 874562 Email subs epemag wimborne co uk Also via the Web at www epemag com Subscriptions start with the next available issue We accept MasterCard Maestro or Visa For past issues see the Back Issues page BINDERS Binders to hold one volume 12 issues are available from the above address These are finished in blue PVC printed with the magazine logo in gold on the spine Price 7 95 plus 3 50 p amp p for overseas readers the postage is 6 00 to everywhere except
180. qually which brings us back to temperature coefficients in relation to parallel connection of transistors Itisnotjustthreshold voltage which varies with temperature and other parameters have a more obvious link to using MOSFETS in parallel The drain source resistance is of particular relevance here Fig 5 shows the variation of R with temperature for DS ON the BS170 The temperature coefficient NORMALISED DRAIN SOURCE ON RESISTANCE Everyday Practical Electronics February 2009 CHANNEL Fig 4 Simplified DMOS power MOSFET structure JUNCTION TEMPERATURE C Fig 5 BS170 MOSFET R Fairchild Semiconductor datasheet BS170 Rev C 1995 DS ON variation with temperature from is clearly positive over the full operating range of the device The positive temperature coefficient of Ry Means that if a 2 heats up due to power dissipation its Ry ox increases For two parallel MOSEETS of the same type this positive temperature coefficient reduces the current in the hottest device as its resistance increases and forces more current to flow in the cooler device The warmer device will tend to cool and the cooler device tends to warm up keeping the current and temperature balanced in the two devices The same balancing effect occurs for any number of parallel devices This balancing is particularly effective when the MOSFETS are close together with a good thermal connection between devices as the
181. r Three input sensitivity settings Overload amp short cir cuit protection protection against incorrect power supply polarity Speaker transient suppression K4004 Kit 43 95 PIC Programmer Suitable for a wide range of Microchip PIC mi crocontrollers onboard configurable 40 pin ZIF socket Microcontroller se lection using patch jumper easy to use programming PlCprog2006 software included SUBD connector set included K8076 Kit 1A Power Supply Low cost universal symmetric power supply just add a suitable transformer and a heatsink trimmers can be replaced by po tentiometers to allow continuous ad 17 95 justment of output LED output indicators K8042 Kit 95 Velleman Instruments We also carry the Velleman range of fully assembled test equipment This range of hand held Scopes and PC based measurement equipment uses all the latest tech niques to achieve state of the art equipment that would be at home in any industrial applications or in the hands of the enthusiast Full specs on our web site Two channel USB PC Oscilloscope A digital storage oscilloscope uses the power your PC to visualize electrical signals Its high sensitive display resolution down to 0 15 combined with a high bandwidth and a sampling frequency of up to 1GHz are giving this unit all the power you need PCSU 1000 USB Scope 229 95 2MHz USB PC Function Generator A digital function gene
182. r voice sound lower or higher built in microphone and power amplifier with volume con trol just add a speaker MK171 Mini Kit Mini PIC Application Module Create your own custom PIC application without the hassle of making the hardware 9 Free programmable I Os Onboard Relay LEDs amp Buzz er PIC16F630 inc VM142 Assembled 7 95 20 95 Prices Exclude Vat 15 UK Carriage 2 50 less than 1kg 5 50 greater than 1kg gt 30 Cheques Postal orders payable to vrsA ESR Electronic Components Ltd PLEASE ADD CARRIAGE amp VAT TO ALL ORDERS Our new autorouter will turn this into this J D du i 1 2 TR le j 1 os TOCA ee omi M kt I 2 2 Sit i n a z 9 HU ES 72 ON J Tes 3073 Ih SCION SCA m2 3h Emu ELM EEG NT uv MD x 7 gt ES M fp SS 5 2 4 4 2 4 OR Eu TENES CERIS 3 mn LLL PI rell a RE NER E Tn rare bitte f mime UCET meer due anl T T i E hd ARIA amp gt HO I ris v wl 1 T 88 ee 4
183. rary DLL You may write custom Windows 98SE 2000 Me XP applications in Delphi Visual Basic C Builder or any other 32 bit Windows application development tool that supports calls to a DLL K8055 Kit VM1 10 Assembled USB Interface Board With a toal of 33 input outputs including ana logue digital and 1PWM output Connection to the computer is galvanically op tically isolated so that dam age to the computer is not possible thus providing a high level of secure implementa tion Supplied with test software amp examples K8061 Kit 48 95 High Power LED Driver Power up to four 1W or two 3W high power LEDs not incl Delivers accurate constant current required by most high power LEDs built in rectifier for easy connection to AC source compact size 4 short circuit protected no heatsink re gt quired K8071 Kit 4 95 VM143 1W for IW LEDs 7 55 VM143 3W for 3W LEDs 7 95 Remote Control by Telephone Turn up to three devices on or off over the telephone It is also possible to check the condition of a switch open or closed A major advantage of this circuit lies in the fact that audio signals are used to tell whether a specific output has been turned on or off Operation is protected by a user defined code which is simply a keyed in from the telephone key pad K6501 Kit 19 95 26 95 18 95 29 95 29 95 USB DMX Interface Control DMX fixtures using a PC and USB interface t
184. rator which can be connected with a PC via USB Standard sig nal waves like sine triangle and rectangle are available other sine waves can be easi ly created The signal waves are created in the PC and produced by the function generator via DDS Direct Digital wave Systhesis PCGU100O0 USB Function Generator 95 00 VELLEMAN is major European distributor of high quality electronic products They have been trading for more than 35 years and operate from Gavere Belgium With a network of over 17 000 dealers in more than 80 countries are now able to offer you the complete range of their electronic kits modules PC based development products and test equip l ment 80 page catalogue and new supplement available email or phone for a copy Full listing and specs of all kits amp modules on our web site PIC Programmer For Microchip FLASH PIC microcontrollers sup ports 4 different 300 mil PICs 8p 14p 18p and 28p test buttons and LED indicators Supplied with program ming examples amp easy connection to a PC through the serial port Supplied with a PIC16F627 and software to compile and program your source code K8048 Kit VM111 Assembled USB Interface A interface board with 5 digital input amp 8 digital output chan nels In addition there are two analogue inputs amp two ana logue outputs with 8 bit resolution All communication routines are contained in a Dynamic Link Lib
185. rature and pressure sensors Wave height and motion logging devices using GPRS and a PC based data analysis package GPRS to ZigBee gateway for remote data acquisition Data acquisition and analysis board for very high current sensing application Controller system and PC interface software for paddles in a wave tank to simulate various wave profiles CCTV camera remote control for 4 monitors and up to 100 cameras Our regular customers include a world leading manufacturer of industrial analytical instruments and a leader in research and development of renewable energy systems 22 Everyday Practical Electronics February 2009 Unforgettable Memories Mark Nelson An experiment using a camera chip to replace a damaged eyeball may have far more applications than the designer intended and the future looks bright for analogue semiconductors Mark Nelson casts an eye over the facts cientists involved with optics must have stronger stomachs than me as I have never felt comfortable with the notion of playing with human eyes So you had better Look away now if you are squeamish although I promise there is no gratuitous gore in this article I must confess I still get the shivers when I read about Logie Baird s 1928 television experiment using an eyeball removed by a surgeon from a young man s head To quote the man himself As soon as I was given the eye I hurried in a taxicab to the laboratory Within
186. re installed with the correct polarity These things have a nasty habit of exploding if they re in the wrong way round The same goes for other electrolytics across the supply rails on the other modules In fact it s not a bad idea to wear safety glasses when switching on for the first time just in case you do have a capacitor in the wrong way around or you accidentally reverse the supply polarity Exploding capacitors and eyeballs generally don t mix too well 4 Use a multimeter to confirm that all the chassis panels are correctly earthed Do that by checking for continuity between the earth ter minal of the IEC socket and each of the panels in turn remove some of the powder coating from an inside surface of each panel to make these checks if necessary Similarly check that the heat sinks are earthed to the chassis and that all external screw heads are earthed 5 Usea multimeter to confirm that the output transistors Q12 and Q14 are Everyday Practical Electronics February 2009 correctly isolated from the heatsink of each power amplifier module Testing and adjustment There are three basic procedures to go through here First you have to check that the power supply module is delivering the correct voltages You then apply power to each power amplifier module in turn and ad just its quiescent current Finally you power up the preamplifier and loudspeaker protector modules and check their oper
187. rials and workmanship used by readers EPE Online its publishers and agents disclaim any responsibility for the safe and proper functioning of reader constructed projects based on or from information published in these materials and works In no event shall TechBites Interactive Inc or Wimborne Publishing Ltd be responsible or liable for any loss of profit or any other commercial damages including but not limited to special incidental consequential or any other damages in connection with or arising out of furnishing performance or use of these materials and works 65 CRM ty Cost P Manufacturing Service 52 BEN QU vd manufa cturec dde s own designs for a discount price The PCB POOL concept has made professional quality PCB prototypes available to students amp hobbyists worldwide Simply send us your files amp receive your prototypes in a few days Download our FREE WATCH UR PCB PCB Layout Software View your PCB as it e Schematic Capture gets manufactured PCB Layout Auto Router amp Auto Placer We send HD images at each production stage Complete Component Library so you can track ils progress Prafessional Version Drilling Exposure 9 Tin Stripping UV curing Hot air levelling ww w free pcb software com www pcb pool com Email sales pcb pool com Free Phone UK 0800 389 8560 Simply send your tiles amp order O
188. rom 0 9999 RPM or above 10 000 RPM optional Two display options for RPM above 9999 RPM Options for 1 RPM 10 RPM or 100 RPM display resolution Automatic display dimming in low ambient light Set up for 1 2 3 4 5 6 8 10 and 12 cylinder 4 stroke engines and 1 2 3 4 5 and 6 cylinder 2 stroke engines Selectable red line RPM Selectable shift light RPM Selectable limiter RPM Selectable number of red line LEDs Selectable display update period Selectable RPM hysteresis for LED bargraph Selectable limiter minimum on time RPM reading is updated every 10ms or 100 times per second Note that because the calculation of RPM is made every 1ms the new RPM value is available almost as soon as the counter value has been captured The resulting RPM value is sent to the bargraph driver to display the latest reading Twin cylinder motorbikes One small problem with this method of RPM measurement is that it does not work with engines that have uneven firing between cylinders It would measure two different RPM readings because of the uneven spacing between successive firing pulses This is mainly a concern with twin cylinder 4 stroke engines with cylinder separations of less than 180 such as from Harley Davidson Ducati and Moto Guzzi To prevent this reading problem we have included setting selections for these engines that count between four successive firing pulses Because the spacing is constant in engine
189. ry 2009 VERY SPECIAL OFFER READER Everyday Practical Electronics and Microchip have teamed up to offer you the chance to buy a PICkit 2 Debug Express Kit DV164121 at an unprecedented discount price In this issue of EPE you have the chance to purchase this kit via microchipDIRECT at an unmissable price of only 9 99 including VAT and Delivery to UK addresses As this is an unprecedented price the offer is limited to one per household UK addresses only one per e mail address Go to http microchipdirect com Register or log on to the site with the Great Britain Union Jack flag and enter the part number DV164121 Add the PICkit to the Shopping Cart and the enter the Coupon number 08 and press the apply coupon button Select checkout which will take you to the address and payment processes remember to accept the terms amp conditions and then place the order Allow up to 28 days for delivery microchip wWwWw micnochipdirect com Conditions This offer is only valid to UK readers Only one PICkit 2 Debug Express Kit per household and or one per e mail address is allowed This offer applies to all UK purchases made before 31st January 2009 via microchipDIRECT and inserting and quoting the correct coupon reference This offer may not be used in conjunction with any other offer This coupon has no cash value This offer may be withdrawn without prior not
190. s Note the kit does not include an infrared remote control handpiece This must be purchased separately Almost any universal remote should be suitable eg Altronics Cat A 1009 or Jaycar AR 1703 30 Note that the shield leads are sepa rately connected to their respective solder lugs on the insulated RCA input sockets Do not connect these shield leads together or to chassis otherwise you ll get an earth loop At the preamplifier end trim each cable to length then strip about 14mm ofthe outer insulation away from each conductor in turn and carefully sepa rate and twist the screening braid wire strands together That done strip about 10mm of insulation from each inner conductor then double each bared end back on itself twist it together and lightly tin with solder The shield wires can also be doubled up twisted and tinned Now secure the audio input leads to the screw terminal blocks Note that it s important to do these screw connections up nice and tight other wise the signal to noise ratio will be compromised Some of the left over figure 8 audio cable can now be used to make the two audio leads that run from the pream plifierto the power amplifier modules Separate the cable into two separate leads and fit an RCA phono plug to one end of each lead red for the right channel black for the left Make sure that each shield wire con nects to the earthy side of its phono plug ie to the terminal that
191. s as well as up or down with PIC12 and 8 MCUs The first devices based upon the enhanced 8 bit mid range PIC MCU core are expected to roll out in the spring of 2009 Third party compiler support for devices utilising the enhanced core will be provided by HI TECH Software CCS microEngineering Labs and Byte Craft Limited For further information visit Microchip s Web site at www microchip com enhanced Everyday Practical Electronics February 2009 Passport to World Band Radio The 2009 edition of Passport to World Band Radio explodes with hundreds of programmes you cannot find elsewhere From the matchless reporting of the BBC to the musical heights of the Andes it is a broadcast menu that is one part Newsweek another National Geographic Every station stands out comedy from England science from Russia waltzes from Austria It is the depth and variety that is missing from ordinary radio and This book covers it all what s on what to buy how to get started It is the world s best selling short wave guide trusted by over a million readers since 1985 560 pages 175 x 235mm colour and B W photos 17 50 IBS Gazelle Book Services Ltd tel 44 0 1524 68765 Email sales gazellebooks co uk Conned It s a safe bet that every EPE reader will have received emails or faxes or even letters which tell of a trapped fortune in a far off land that can be released for sharing by h
192. s digital specified components i on construction and 3 cameras data samplers and the list goes identification of parts e Kit includes PCB and all specified electronic components kit KC 5474 LOW VOLTAGE BATTERY WARNING KIT 9000 3 00 20 50 This circuit monitors any battery voltage between 3 15 volts utomatically supplies power for 12V emergency lighting Secure on line ordering once set Whenever the voltage falls below a predetermined uring a blackout The system has its own 7 5Ah SLA battery e ALL prices in Pounds Sterling value red LED lamp lights up It hich is maintained via an external smart charger Includes Minimum order ONLY 10 does not however automatically anual override and over discharge disconnect the battery Uses a rotection for the tiny amount of power from attery Kit supplied with ORDER YOUF FREE e 8 pages LI JI Nl the battery being monitored electronic Could save you n a E 0 E nponents screen embarrassment or a a T CATALOGUE rinted PCB front panel TODAY fortune by avoiding nd case Charger and SLA 1 4 Lo battery damage tery available separately Jaycar Electronics a x KG 9090 95 plus postage amp packing This kit can operate as a twilight on off switch or as a light trigger relay Oper
193. s ceiling BECOME A PIC PROJECT BUILDER WITH THE HELP OF EPE NOTE The PDF files on this CD ROM are suitable to use on any PC with a CD ROM drive They require Adobe Acrobat Reader included the CD ROM EPE PIC PROJECTS CD ROM ORDER FORM Please send me quantity EPE PIC PROJECTS VOL 1 CD ROM Price 14 45 each the world includes postage to anywhere in enclose cheque PO bank draft to the value of please charge my Visa Mastercard Maestro CAINO Card Security Code The last 3 digits on or just under the signature strip SEND Everyday Practical Electronics Wimborne Publishing Ltd Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Tel 01202 873872 01202 874562 Email orders epemag wimborne co uk Payments must be by card or in Sterling cheque or bank draft drawn on a UK bank Normally supplied within seven days of receipt of order Send a copy of this form or order by letter if you do not wish to cut your issue Order on line from WWW epemag com or by Phone Fax Email or Post EPE PIC RESOURCES V2 CD ROM ORDER FORM Please send me quantity PIC RESOURCES V2 CD ROM B Price 14 45 each includes postage to anywhere the world PROG OSS m Bi EHHOHOHOE HON HOHOHOH BOE OHOHOHOHOH OHOHOHOHOHOHOHOHOHOHOHOHOHOHOH HONO HOHOHOHO NOE OHOHOHOHOHOHOHOHOHOHOHOH
194. s construction work A uniquely concise and practical guide to getting up and running with the PIC Microcontroller The PIC is one of the most popular of the microcontrollers that are transforming electronic project work and product design Assuming no prior knowledge of microcontrollers and introducing the PICs capabilities through simple projects this book is ideal for use in schools and colleges It is the ideal introduction for students teachers technicians and electronics enthusiasts The step by step explanations make it ideal for self study too this is not a reference book you start work with the PIC straight away The revised third edition covers the popular reprogrammable Flash PICs 16F54 16F84 as well as the 12F508 and 12F675 270 pages Order code NE36 20 99 INTRODUCTION TO MICROPROCESSORS AND MICROCONTROLLERS SECOND EDITION John Crisp If you are or soon will be involved in the use of microprocessors and microcontrollers this practical introduction is essential reading This book provides a thoroughly readable introduction to microprocessors and micrcontrollers Assuming no previous knowledge of the subject nor a technical or mathematical background It is suitable for students technicians engineers and hobbyists and covers the full range of modern micros After a thorough introduction to the subject ideas are developed progressively in a well structured format All technical terms are carefully introduced and
195. s eventually sent to my phone and lo it worked briefly before stopping again My favourite solution for handling outbound mail remains AuthSMTP www authsmtp com which I configured to run on my mobile phone All outbound problems have now ceased and AuthSMTP s technical support remains consistently excellent helped by the fact that the tech guy uses a Tytn II himself My Tytn II is now in constant use for checking email hardly ever for phoning and it fetches the first few kilobytes only any interesting looking mails are then fully downloaded manually Unsavoury spam Spam remains an infernal problem that impinges on mobile email Approximately 8796 of all mail I receive on my regular email address is spam and this alone would drown out the smartest of Windows Smartphones Spam is the scourge of today s wired world and it is especially intrusive when trying to check mobile email My solution is to utilise the ClearMyMail service on my main work email address Its statistics show me that out of 4 199 mails it checked 3 650 of them were spam ClearMyMail could be the saviour for spam sufferers everywhere and it is extremely efficient at sifting out unwanted mail The cost of this service is extremely low considering the vast amount of time it saves More importantly it also unleashes my mobile email and in conjunction with AuthSMTP permits me to handle email correspondence on the move Be sure to check my Net Work
196. scanned in from an old speedo Once you have the arc and the in crements you can use the software to delete the numbers and any other markings you don t want That done measure the width of the scale on the meter and then size the on screen version to match this and print it out without any numbers on it Next carefully remove the original scale most meters are held together with tape with the scale glued in place and temporarily place your un num bered scale behind the pointer To provide a variable calibration voltage use the approach shown in Fig 2 This involves wiring a 10kQ potentiometer across the output of a discarded plugpack By adjusting the pot you can vary the calibration voltage from OV up to the maximum voltage provided by the plugpack The multimeter is included so that p wo 1 5 2 6 Hmm JE instruments gee that sounds like a good brand When you make your own scales you can put anything you like on them MULTIMETER VOLTS PLUG PACK POWER SUPPLY 100kQ MULTI TURN TRIMPOT Recycle It On the right is one of a pair of VU meters removed from an old cassette deck At left is its modified brother recalibrated and rescaled as a voltmeter reading up to 34V you can measure the voltage being fed to the VU meter Calibration So how do you perform the calibra tion First adjust the 100kQ trimpot sothat the most commonly read
197. stakes 1 0 220 semiconductor insulating kit This means that if VR1 is set at say 1kQ then the voltage across this resis tor will be 1kQ x 11 36m4A or 11 36V This voltage is then added to the 1 25V reference to derive the output voltage in this case 12 61V In practice however the current flow out ofthe ADJ terminal also contributes slightly to the final output voltage This current is of the order of 100UA So if VR1 is set to 1kQ this can add 0 1V to the output ie we get 12 71V If you are interested in the output voltage equation then it is Vout 1 R1 R2 apy x R2 where is the output voltage Vrer is the voltage between the OUT and ADJ terminals and apy is the cur rent out of the ADJ terminal typically 50uA but can be as high as 100uA R1 is the resistance between the OUT and ADJ terminals while R2 is the resistance between the ADJ terminal and ground OV Protection Diode D1 in series with the input provides reverse polarity protection This means that if you connect the supply voltage around the wrong way you cannot do any damage Diode D2 protects the regulator should the input become shorted to ground If that happens D2 becomes forward biased and conducts effec tively preventing any reverse current Everyday Practical Electronics February 2009 MAY NEED TO BE LARGER 01 03 1N4004 a A K Constructional Pro
198. sterical ranting of Sc S OT BNET ihe mosse features a 10 LED bar graph that lights the LEDS in response Daleks The kit includes PCB with overlay enclosure speaker this kit is for you The to the measured voltage preset 9 16V 0 5V or 0 1V ranges and all components nas electronics are mounted ing complete with a fest response time high input impedance and i a the supplied jiffy box and auto dimming for night time driving the radar gun assembly is 2 Kit includes PCB with overlay LED bar graph and all can be made simply with electronic components two coffee tins fitted end M to end The circuit needs z LDL E 19VDC at only 130mA so you can use a small SLA or rechargeable battery pack Kit includes PCB and all specified components PC INFRARED 433MHZ REMOTE KIT CONSTRUCTORS TRANSCEIVER KIT SWITCH KIT MANUAL 6 95 Did you know that most Pentium 11 75 uin 2 Suitable for remote control of practically anything up to a range i of 200m The receiver has momentary or toggle output and the A must for amateur SIUS RIT NS momentary period be adjusted Up to five receivers can be the box This quick ug jm used in the same vicinity Short useful the T more experienced and easy kit plugs into your motherboard to provide IR support form kit contains two PCBs and all P Huge sa of information for external devices such as notebook computers PDA
199. subjects which have proved difficult for example 25 complement are clearly explained John Crisp covers the complete range of microprocessors from the popular 4 bit and 8 bit designs to today s super fast 32 bit and 64 bit versions that power PCs and engine management systems etc Order code NE31 22 00 298 pages 222 pages Everyday Practical Electronics February 2009 The books listed have been selected by Everyday Practical Electronics editorial staff as being of special interest to everyone involved in electronics and computing They are supplied by mail order direct to your door Full ordering details are given on the last book page FOR A FURTHER SELECTION OF BOOKS AND CDROMS SEE THE SHOP ON OUR UK WEBSITE www epemag com All prices include UK postage EASY PC CASE MODDING R A Penfold Why not turn that anonymous grey tower that is the heart of your computer system into a source of visual wonderment and fascination To start you need to change the case or some case panels for ones that are transparent This will then allow the inside of your computer and its working parts to be clearly visible There are now numerous accessories that are relatively inexpensive and freely available for those wishing to customise their PC with added colour and light Cables and fans can be made to glow interior lights can be added and it can all be seen to good effect through the transparent case Exterior lighting and
200. tal circuits It is used to indicate to the receiving equipment that a fresh bit of data is available on the data line and is ready Fig 5 Timing diagram for a basic synchronous data link In this example there are eight bits of data in the group but within reason any required number of bits can be used for processing There is more than one way of arranging things but the waveform diagram of Fig 5 helps to explain a typical approach to synchronous communication With this scheme of things the clock signal goes through a low to high transition each time a fresh bit of data is ready to be read The receiving device must be designed to almost immediately detect each transition of this type and then read the bit of data In theory it is possible for the data to be sent as fast or as slow as you like but in practice there is obviously an upper limit It is important that data is not transmitted at a rate which is faster than the receiving device can handle properly With a computer as the sending device this is unlikely to be a problem because the transmission rate will usually be slow in relation to the speed at which the receiving device can process received data It might be necessary to deliberately slow things down when the receiving device is a computer or in any case where the receiving device is relatively slow Matter of timing Returning to the waveform diagram of Fig 5 in this example there is a series of eight d
201. the input voltage has a lot of ripple In addition you should make sure that the input 21 Constructional lo p ol 698 O REGULATOR Fig 4 this is the full size etching pattern for the PC board Check your board for defects before mounting any of the parts voltage does not go above C1 s 25V rating Increase C1 s working voltage rating to 35V if it does In fact you can apply up to 35V to the input if C1 is a 35V type Adjusting the output Note that the voltage applied to the supply must be several volts higher than the required output voltage This Our capabilities PIC microcontroller applications Analogue and digital design Data acquisition Compact Control Design is necessary in order for the regulator to provide regulation In practice the minimum volt age across REG1 required for regulation is called the dropout voltage For the LM317T this voltage varies with the current and is typically 1 5V ui for currents be low 200mA rising to 1 7V at 500mA and 2V at 1A Note that the vol age drop across diode D1 must be added to the dropout voltage in order to calculate the required input volt age For example if our power supply draws 200mA and the required output voltage is 6V then the input voltage must be 6V plus 0 7V to compensate for the voltage across D1 plus 1 5V for the dropout voltage ie the input voltage must be 2 2V higher than the outp
202. these figures into Ohm s Law ie I V R and you ll find that the BY JULIAN EDGAR 02 D Here a side adjusted multiturn trimpot has been used as the series variable resistor This makes calibrating the meter easy meter current is only about 0 5mA for full scale deflection FSD Building it If you need to measure a voltage that rises only to about 0 4V all you need do is connect the meter straight across the supply However it s much more likely that you ll want to measure a peak voltage of 5V 12V or even 24V Fortunately it s very easy to decrease the sensitivity ofthe meter just wirea variable resistor preset in series with the meter as shown in Fig 1 But how do you make the scale match the readings you want the meter to show Most VU meters use a non linear movement that is the needle moves less for a given voltage increment at the top end of the scale than it does towards the bottom This means that you can either position the scale markings closer together as you move up the meter scale or you can space the markings evenly and jump further between numbers We chose to do the latter Meter scale You can use your PC and printer to make the new scale You could scan in the original scale and modify it Everyday Practical Electronics February 2009 but in practice it s best to start with the scale from another instrument The meters shown here use a scale that was originally
203. to display the RPM Calibration and op tion settings are set using switches 51 to S3 while LED34 and LED35 show the display status IC3 operates at 20M Hz as set by the crystal X1 The ignition signal from the engine can be obtained from the car s Engine Control Unit ECU from a reluctor Hall effect trigger or points or via an ignition coil connection for cars that have a distributor Two separate inputs are provided a high level input for connecting to high voltage signals such as from an ignition coil and reluctor and a low level input for a low voltage source such as the ECU The high level signal is fed via an attenuation network consisting of a 22kQ resistor two 47nF capacitors and the 10kQ resistor to ground The resulting signal is coupled via a 2 2uF capacitor to remove any low frequency or DC voltages that may be present and limited by 10V Zener diode ZD2 The signal is then applied to the pin 6 input of IC3 via a 10kQ limiting resistor By contrast the low level input is applied to pin 6 via a 2 2kQ resistor and 100Q resistor Diodes D3 and D4 limit the signal swing to between 0 7V and 5 7V IC3 s pin 6 input also incorporates its own protection diodes and these are protected from excessive current by the 1000 resistor Display section The display section shown in Fig 4 mainly involves IC1 and IC2 which might just have been designed for our very purpose Each M5451 IC can drive up to 35 LEDs and a d
204. tors Thyristors Relays and much more COMPONENTS PHOTOS Click Data for a complete guide to the pin layouts of i c s transistors etc Click More Information for detailed background information with many animated diagrams A high quality Nearly all the circuits can be instantly simulated in Crocodile Technology not included the CD ROM and you can customise the designs as required 200 jpg images of electronic components This selection of high resolution photos can be used to enhance projects and presentations or to help with training and educational material They are royalty free for use in commercial or personal printed projects and can also be used royalty free in books catalogues magazine articles as Get TINA Flowcode for a total of just 50 including VAT and postage WHAT S INCLUDED Light Modules Temperature Modules Sound Modules Moisture Modules Switch Modules Astables including 555 Remote Control IR amp Radio Transistor Amplifiers Thyristor Relay Op Amp Modules Logic Modules 555 Timer PIC PICAXE Output Devices Transistor Drivers Relay Motor Direction amp Speed Control 7 Segment Displays Data sections with pinouts etc Example Projects Full Search Facility Further Background Information and Animated Diagrams Runs in Microsoft Internet Explorer All circuits can be viewed but can only be simulated if your computer has Crocodile Technoloy version 410 or later A free
205. trial version of Crocodile Technology can be downloaded from www crocodile clips com Animated diagrams run without Crocodile Technology Single User 39 00 inc VAT well as worldwide web pages subject to Multiple Educational Users under 500 students 59 00 plus VAT Over 500 students 79 00 plus VAT restrictions see licence for full details UK and EU customers add VAT at 15 to plus VAT prices Now contains Irfan View image software for Windows with quick start notes included Minimum system requirements for these CD ROMs Pentium PC CD ROM drive 32MB RAM 10MB hard disk Price 19 95 inc VAT space Windows 95 98 NT 2000 ME XP mouse sound card web browser Please send me CD ROM ORDER FORM N Electronic Projects Electronic Circuits amp Components V2 0 ORDERING ALL PRICES INCLUDE UK O Analogue Electronics Version required POSTAGE O Digital Electronics V2 0 O Hobbyist Student 1 Analogue Filters O Institutional Student Single User Standard Version price Electronics CAD Pack O Institutional Professional 10 user includes postage to most countries the world EU residents outside the UK add 5 for airmail postage per order O Robotics amp Mechatronics O Site licence O Assembly for PlCmicro O C for 16 Series PlCmicro V4 O Flowcode V3 for PlCmicro Digital Works 3 0 PlCmicro Development Board hardware I 0 fl
206. tronic components and their corresponding symbols in circuit diagrams Included in the Institutional Versions are multiple choice questions exam style questions fault finding virtual laboratories and investigations worksheets ANALOGUE ELECTRONICS U dme ea 00000 ee Lan om cl eee ee ee ee ee eee eee Virtual laboratory Traffic Lights Analogue Electronics is a complete learning resource for this most difficult branch of electronics The CD ROM includes a host of virtual laboratories animations diagrams photographs and text as well as a SPICE electronic circuit simulator with over 50 pre designed circuits Sections on the CD ROM include Fundamentals Analogue Signals 5 sections Transistors 4 sections Waveshaping Circuits 6 sections Op Amps 17 sections covering everything from Symbols and Signal Connections to Differentiators Amplifiers Single Stage Amplifiers 8 sections Multi stage Amplifiers 3 sections Filters Passive Filters 10 sections Phase Shifting Networks 4 sections Active Filters 6 sections Oscillators 6 sections from Positive Feedback to Crystal Oscillators Systems 12 sections from Audio Pre Amplifiers to 8 Bit ADC plus a gallery showing representative p c b photos DIGITAL ELECTRONICS V2 0 Digital Electronics builds the knowledge of logic gates covered in Electronic Circuits amp Components above and takes users through the subject of digital electro
207. tt Interfacing PICs to the Internet via Ethernet Part 5 NET WORK by Alan Winstanley Mail on the move Unsavoury spam Regulars and Services EDITORIAL NEWS Barry Fox highlights technology s leading edge Plus everyday news from the world of electronics EPE MICROCHIP EXCLUSIVE SPECIAL OFFER A Microchip PICkit 2 Debug Express Kit for only 9 99 BACK ISSUES Did you miss these ELECTRONICS MANUALS The Modern Electronics Manual and Electronic Service Manual on CD ROM PIC PROJECTS CD ROM A plethora of handPlCed projects PIC RESOURCES CD ROM EPE PIC Tutorial V2 plus PIC Toolkit Mk3 and a selection of PIC related articles CD ROMS FOR ELECTRONICS A wide range of CD ROMs for hobbyists students and engineers SUBSCRIBE TO EPE and save money READOUT Matt Pulzer addresses general points arising DIRECT BOOK SERVICE A wide range of technical books available by mail order plus more CD ROMs EPE PCB SERVICE ADVERTISERS INDEX Readers Services Editorial and Advertisement Departments 10 24 AG 48 23 36 40 44 54 58 19 38 AS 52 53 60 63 64 67 70 72 All prices INCLUDE 17 5 VAT Postage amp Packing Options Up to 2Kg gross weight UK Standard 3 7 Day Delivery 3 95 UK Mainland Next Day Delivery 8 95 Europe EU 6 95 Rest of World 9 95 up to 0 5Kg lOrder online reduced price UK Postage We accept all major credit debit cards Make cheques PO
208. udspeaker leads to the power ampli fier modules Watch the ventilation That s it your new 20W Class A Ster eo Amplifier is now ready for action Just one final thing as previously mentioned the heatsinks get quite hot and the air must be allowed to flow freely through the bottom and top ventilation slots This means the amplifier must sit out in the open on a hard level surface Do not enclose itin a cabinet and do not stack anything on top of it EPE www stewart of reading co uk OSCILLOSCOPES ON EXTRA SPECIAL OFFER TEKTRONIX 465 Dual Trace 100MHZ Delay Sweep 465B Dual Trace 100MHZ Delay Sweep 466 Dual Trace 100MHZ Analogue Storage 468 Dual Trace 100MHZ Delay Sweep Digital Storage 475 Dual Trace 200MHZ Delay Sweep 2214 4 Ch 20MHZ Analogue 1 5 5 95 2215A Dual Trace 60MHZ Delay Sweep Dual TB 2220 Dual Trace 60MHZ Digital Storage Cursors 125 2225 Dual Trace 5OMHZ 2230 Dual Trace 100MHZ Digital Storage Cursors 195 2235 Dual Trace 100MHZ Dual TB 2430 Dual Trace 150MHZ 100 MS S 2445 4 Ch 150MHZ Delay Sweep Cursors etc 2445A 4 Ch 150MHZ Delay Sweep Cursors etc 2445B 4 Ch 150MHZ Delay Sweep Cursors 2445B With DMM 4 Ch 150MHZ Delay Sweep Cursors 300 STEWART of READING 17A King Street Mortimer Near Reading RG7 3RS Telephone 0118 933 1111 Fax 0118 933 2375 www stewart of reading co uk 9am 5pm Monday to Frida For Limited Perio
209. ulation techniques which provide a superb tool for learning the Virtual PICmicro micro controller this is a simulation tool that allows users to write and execute MPASM assembler code for the PIC16F84 microcontroller on screen Using this you can actually see what happens inside the PlCmicro MCU as each instruction is executed which enhances understanding e Comprehensive instruction through 45 tutorial sections e Includes Vlab a Virtual PlCmicro microcontroller a fully functioning simulator e Tests exercises and projects covering a wide range of MCU applications e Includes MPLAB assembler e Visual representation of a PlCmicro showing architecture and functions e Expert system for code entry helps first time users e Shows data flow and fetch execute cycle and has challenges washing machine lift crossroads etc e Imports MPASM files PRICES Prices for each of the CD ROMs above are Order form on next page Supports PlCmicro microcontrollers with A D converters Can be powered by USB no power supply required HARDWARE eur pi NI Ld S n j F E fj Lac 57 A ae ys As da MP E x Pv uc 1 55 including VAT and postage supplied with USB cable and programming software 40 OFF Buy the Development Board together with any Hobbyist Student or Institutional versions of the software CD ROMs listed b
210. ults are by nature analogue This book is written entirely for a fault finder using only the basic fault finding equipment a digital multimeter and an oscilloscope The treatment is non mathematical apart from Ohm s law and all jargon is strictly avoided Order code NE22 ELECTRONIC TEST EQUIPMENT HANDBOOK Steve Money In most applications of electronics test instruments are essential for checking the performance of a system or for diagnosing faults in operation and so it is important for engineers technicians students and hobbyists to understand how the basic test instruments work and how they can be used The principles of operation of the various types of test instrument are explained in simple terms with a minimum of mathematical analysis The book covers analogue and digital meters bridges oscilloscopes signal generators counters timers and frequency measurement The practical uses of these instruments are also examined 109 9 95 274 pages 33 99 206 pages DIGITAL GATES AND FLIP FLOPS lan R Sinclair This book intended for enthusiasts students and technicians seeks to establish a firm foundation in digital electronics by treating the topics of gates and flip flops thoroughly and from the beginning Topics such as Boolean algebra and Karnaugh mapping are explainend demonstrated and used extensively and more attention is paid to the subject of synchronous counters than to the simple but
211. ur network but only to our embedded webserver of course Opening up a safe pathway from the Internet into your network is not an unusual thing to do and routers provide a mechanism to do this which is quite safe so long as it is set up carefully It uses a network address translation table to map specific IP applications such as HTTP for web browsers to a single specified IP address on your private network You choose the local IP address program that address into your web server and then your web server becomes accessible to the whole world A typical router NAT setup screen is shown in Fig 2 and the user manual for your router should explain how to set up the feature The public IP Address shown in Fig 2 is the IP address by which you are known on the Internet It is assigned by your ISP to you automatically when you plug in your modem For home users this value is normally dynamic if you have a power cut when your modem powers up again it will more than likely be assigned a new public IP address For normal Internet access this is never important you initiate all contact with the Internet from home and the responses work their way back through the path that your request made Forsomeoneto connectto yourembedded server they are going to need to know your Public IP address which is inconvenient Most people are used to connecting to web servers by a name containing a domain name at the least and they are certainly
212. uring a trip to your local council tip and in notime at all you ll have more thermo stats than you know what to do with So let s take a look at the characteristics of each design Frying pan thermostat electric fry ing pans and electric woks use a thermostat that s integrated into the module that plugs into the handle The module has a knob on it for setting the temperature and a stain less steel probe about the length of your little finger but a bit smaller in diameter These thermostats can be set to operate from about 40 C to 200 C Their design makes them suitable for applications where the probe needs to remotely sense temperature eg by being pushed through a grommet and into a pipe The hysteresis ie Table 1 Characteristics Of Thermostats Electric Frypan Thermostat Tempera Wide 40 ture Range 200 C Hysteresis Sensitivity Clothes Thermostat Fairly wide 60 200 C Large Oil Filled Heat Water Bed er Thermostat Thermostat Narrow 5 Narrow 25 50 50 me Many not snap Most snap Short stainless Whole thermo Whole thermo Remote copper 9 Steel probe stat stat bulb Everyday Practical Electronics February 2009 Recycle It Whenever you throw away an old TV or VCR or washing machine or dishwasher or printer do you always think that surely there must be some good salvageable components inside We
213. ut classic radios from the 1920s to the end of the 1960s All the important makes and models are discussed and the author also covers buying and selling care and restoration and many other topics including foreign radios and radio related ephemera Illustrated with hundreds of colour photographs this is the perfect collector s companion to the fascinating topic 208 pages hardback Order code CVR 21 95 ALL PRICES INCLUDE UK POST amp PACKING Everyday Practical Electronics February 2009 PROJECT BUILDING ELECTRONIC PROJECT BUILDING FOR BEGINNERS R A Penfold This book is for complete beginners to electronic project building It provides a complete introduction to the practical side of this fascinating hobby including the following topics Component identification and buying the right parts resistor colour codes capacitor value markings etc advice on buying the right tools for the job soldering making easy work of the hard wiring construction methods including stripboard custom printed circuit boards plain matrix boards surface mount boards and wire wrapping finishing off and adding panel labels getting problem projects to work including simple methods of fault finding In fact everything you need to know in order to get started in this absorbing and creative hobby Order code 92 5 49 BUILDING VALVE AMPLIFIERS Morgan Jones The practical guide to building modifying f
214. ut voltage Therefore we need to apply 8 2V minimum to the input for regula tion This is the absolute minimum and to ensure correct regulation un der varying loads a 9V input tothesupply would be ideal Note also that any ripple on theinput supply that drops below the required volt age will cause problems since the supply will not be regulated dur ing these low going excursions Once E you ve connected the supply it s just a matter of adjust ing trimpot VR1 to set the required output voltage Finally note that in some applications you might want to replace VR1 with a fixed resistor eg if VR1 s setting is close to a standard fixed value This has been catered for on the PC board just replace VR1 with resistor R2 shown dotted Electronics and Software design Phone 01260 281694 Fax 01260 501196 enquiries compactcontrol co uk Power supplies and power control q p e Ultra low power applications 77 Woolston Avenue GPRS SMS communications Congleton USB RS232 422 485 IrDA interfaces Cheshire Schematic capture and PCB layout CW12 UK Firmware development in C and assembler Company number 5528711 Software development using C and visual studio Examples of completed projects Engine control unit Diesel injector driver and USB CANbus interface for a specialist automotive company Modbus based 24 bit data acquisition system with direct connection to tempe
215. values 10kQ R1 R2 100k 2 R3 4 0 2 R4 All 0 25W carbon film Capacitor C1 value 100nF 0 1F polyester Switch 1 On Off single pole single throw SPST Pushswiteh 2 push to make release to break Battery B1 9V and connecting leads Protobloc and wire links ooooo Je e fe fe 3 e 0 e e peg 1 1 pura e ej ej ej ej emote Control BATTERY Fig 5 4 Assembly of the Simple Dice on Protobloc Everyday Practical Electronics February 2009 51 VOLUME 1 MINI CD ROM A plethora of 20 hand PlCked PIC Projects from selected past issues of EPE Together with the PIC programming software for each project plus bonus articles The projects are PIC Based Ultrasonic Tape Measure You ve got it taped if you this ultrasonic distance measuring calculator EPE Mind PiCkler Want seven ways to relax Try our PIC controlled mind machine PIC MIDI Sustain Pedal Add sustain and glissando to your MIDI line up with this inexpensive PIC controlled effects unit PIC based MIDI Handbells Ring out thy bells with merry tolling plus a MIDI PIC up of course EPE Mood PiCker Oh for a good night s sleep Insomniacs rejoice your wakeful nights could soon be over with this mini micro under the pillow PIC Micro Probe hardware
216. w the Library section EPE PRINTED CIRCUIT BOARD SERVICE Order Code Project Quantity Price enclose payment of cheque PO in sterling only to Everyday Practical Electronics E vr Gard INO Se kee ena bie Nor Valid From Expiry Date Card Security No Maestro Issue No Signature Note You can also order PCBs by phone Fax or Email or via the shop on our website on a secure server http www epemag com Everyday Practical Electronics February 2009 CEASSIFIEDFADVERTISEMENTS Everyday Practical Electronics reaches more UK readers than any other UK monthly hobby electronics magazine our sales figures prove it We have been the leading monthly magazine in this market for the last twenty three years If you want your advertisements to be seen by the largest readership at the most economical price our classified page offers excellent value The rate for semi display space is 10 VAT per centimetre high with a minimum height of 2 5cm All semi display adverts have a width of 5 5cm The prepaid rate for classified adverts is 40p VAT per word minimum 12 words All cheques postal orders etc to be made payable to Everyday Practical Electronics VAT must be added Advertisements together with remittance should be sent to Everyday Practical Electronics Advertisements Sequoia House 398a Ringwood Road Ferndown Dorset BH22 9AU Phone 01202 873872 Fax 012
217. want to check out the easiest and safest way to protect RC7 UART s RX pin during programming ideas welcome Making the tool bi directional with what I know now is not an issue and should be easily implemented I want to make it all stand alone from pk2cmd I m calling some of its routines for convenience at the moment and investigate the seemingly undocumented protocols that the PICkit 2 uses to access the PIC s ICD for debugging If anyone would like to help out or has any useful suggestions please let me know I plan to eventually release it as an open source project chris c via Chat Zone Good luck with the project chris c Can anyone offer assistance EVERYDAY PRACTICAL ELECTRONICS Stewart Kearn 01202 873872 or email Stewart kearn wimborne co uk Atlas Star Pack Atlas Atlas LCR Premium Carry Case Atlas DCA Model DCA55 Semiconductor Analyser Identifies type and pinout Connect any way round Measures gain junction characteristics and more Now with premium strong probes Measure capacitance and ESR Capacitance from 1uF to 22 000uF TA deeds ie Atlas LCR ESR from 0 01 ohms to 20 ohms Features our unique automatic discharge function Atlas LCR Model LCR40 Passive Component Analyser Automatic component identification inductor capacitor or resistor Auto frequency selection Measures main resistance of inductors automatically component value and
218. wn black yellow brown red red orange brown brown black orange brown 5 Band Code 1 brown black black orange brown red red black red brown brown black black red brown yellow violet black brown brown orange orange black brown brown red red black brown brown brown black black brown brown brown red black brown brown red red black black brown brown black black black brown yellow violet red brown orange orange red brown red red red brown brown black red brown brown red red brown red red brown brown brown black brown brown ERUNT ELT URL ERAT ESL EU EUNT EUR a a N oO 16 Everyday Practical Electronics February 2009 IC2 UNDER DISP1 DISP2 DISP3 ICT UNDER lt PITE LED1 LDR FRONT VIEW 09 amp 9 1 gt Diis Constructional Project DISPA Queer Qe GD g J 2208 Inf gt LED2 10 WAY TRANSITION CONNECTOR IC2 M5451 REAR VIEW Fig 6 here s how to assemble the display PC board The 7 segment displays and the LEDs all sit flush against the board while the LDR should be mounted so that its face is level with the tops of the LEDs The two display driver ICs IC1 and IC2 are mounted on the rear of the display board as shown on the right Use a soldering iron with a fine tip to solder their pins to the PC pads Als
219. xist ing double ended connectors That done install an extra double ended connector at the GND terminal to go with the existing single ended con nector at the input end of the board see Fig 1 Make sure that the screws that hold these connectors in place are done up nice and tight You will need a screw driver to hold the head of each screw in place and a ratchet driven socket to tighten up the nuts Having added the extra connectors the power supply board can now be mounted in position Secure it using M3 x 10mm screws and flat washers Leave the power toroid transformer out for the time being that step comes a little later after you ve installed the low voltage DC wiring Wiring up Fig 1 shows the wiring routes It s not nearly as intimidating as it ap pears at first sight as most of it simply consists of DC supply wiring to the various modules In addition there s a small amount of audio signal cabling plus the loudspeaker cabling and the mains wiring As can be seen most of the supply wiring is terminated using insulated female spade connectors These simply plug into the quick connect spade ter minals on the various modules Screw terminal blocks handle most of the other terminations the exceptions be ing the RCA phono input sockets on the two audio power amplifier boards By the way a ratchet driven crimp ing tool see photo is an absolute necessity when it comes to installing the crimp connect
220. y are in a single power transistor formed from thousands of small MOSFETs connected in parallel some power devices have over 20 000 parallel transistor cells Thus in general MOSFETs can work in parallel both in discrete and integrated circuits Transfer characteristic However the situation is not quite as simple as it seems from just looking at and the temperature coefficient of threshold voltage has a role as we will see in a moment The graph in Fig 6 shows the transfer characteristics also known as transconductance characteristics of the BS170 MOSFET This graph shows the relationship between drain source current output and gate source voltage input Fig 6 shows the characteristics for three different temperatures Looking at the top 55 lt z LLI ee ee z lt ag a E Vas GATE TO SOURCE VOLTAGE V Fig 6 BS170 MOSFET transfer 1995 of the graph we can clearly see that for a given the drain current decreases as temperature increases negative temperature coefficient This is in line with our previous discussion and what we would expect from the positive temperature coefficient of However for low values of lt the temperature coefficient of drain current is positive This is not very clear on Fig 6 so a portion of the graph is redrawn approximately in Fig 7 For all three temperatures shown and any we care to plot the graph has an inflection point wh
221. y responds to the change in en gine revs while the true RPM will be shown on the 4 digit display with up to one RPM resolution A gear shift light and a rev limiter output are standard features and it can operate with virtually any car or motorcycle except magneto ignition 10 Its vast array of optional setting adjust ments makes this tachometer a truly versatile instrument For performance cars and motorcycles this versatility includes the ability to display engine speed above 10 000 RPM On display The circular display section of the tachometer has been made as small as is practical and it can be installed within the instrument cluster of your car if there is sufficient space available Alternatively it can be housed in a cylindrical case and mounted using a suitable holder on the dashboard windscreen or instrument cluster The main electronics part of the tach ometer needs to be mounted under the dashboard or within a side cover in a motorcycle The LED bargraph is arranged in a 76mm diameter circle that covers a 286 span The 32 LEDs are green except for the extreme clockwise end which uses five red LEDs to indicate the red line RPM You can increase the red line indication to as many as 10 LEDs Everyday Practical Electronics February 2009 Constructional Project 305 FOR RESOLUTION 300ms FOR 100RPM RESOLUTION TRADITIONAL DIGITAL TACHOMETER Fig 1 the basic arrangeme
222. y supplied automotive crimp kits They are not up to the job for a project like this as the amount of pressure that s applied to the crimp connectors will vary all over the place This will result in unreliable and unsafe connections especially at the mains switch and IEC socket terminals By contrast a ratchet driven crimp ing tool applies a preset amount of pressure to ensure consistent reli able connections angles and are routed to the 22V and 22V terminals 2 Install the 22V OV and 22V sup ply wiring between the power sup ply board and the preamplifier 3 Install the 22V and OV wiring between the preamplifier and the loudspeaker protector module Note that this wiring actually runs behind the bridge rectifier Fig 1 shows it in front for clarity and is tied down to one of the transformer ventilation slots An adhesive cable tie mount at the front left corner of the power supply board provides a second anchorage point 4 Install the 22V wiring between the bridge rectifier BR1 and the power supply board 5 Install earth leads from the power supply board to the main chassis earth point and from the pream plifier board near the volume pot to its adjacent chassis earth AC Sense leads The two AC Sense leads that run from the bridge rectifier to the loud speaker protector are next on the list These are the blue leads that run to BR1 s AC terminals in Fig 1 First twist th
223. yback connector down so that it shorts against the metal case of BR1 To avoid this bend each male connector upright after plugging in the transformer lead and secure it in this position using a cable tie see photo It s also a good idea to fit cable ties at both ends of the twisted pairs to keep the wiring tidy 22 Mains wiring It s now time to connect the trans former primary leads brown and blue and install the rest of the mains wiring Take particular care with the mains wiring your safety depends on it In particular be sure to use fully insulated spade connectors for all connections to the IEC socket and mains switch As shown in Fig 1 the transformer s blue primary lead connects to the Neutral terminal on the IEC socket while its brown primary lead runs directly to the top terminal of the mains switch In addition you need to run a heavy duty 32 0 20 mains rated cable brown between the bot tom terminal of the mains switch and the Live terminal of the IEC socket The best place to start this wiring is at the power transformer Here s the procedure step by step STEP 1 run the primary leads straight down the side of the transformer to the chassis and secure them together at top bottom and centre using three cable ties STEP 2 cut a 600mm length of brown 32 0 20 heavy duty cable this will be used to connect the IEC socket Live terminal to the mains switch STEP 3 twist this lead tog
224. yester capacitor individual LEDs pin 1 While this arrangement does not This capacitor is mimic the dots on the six faces of a unpolarized so dice it does provide an effective but IC2 type 4017 decade counter it does not mat simple electronic solution it takes the ter which way effort and some would say the fun round it is con out of rolling a traditional dice and nected picking it up off the floor Notes Use the Circuit Tester to confirm PIN 1 Use She seca Or find the anode a lead of each of Viewed from above an indented dot tre pole and the six LEDs as described in Part 1 of and a half moon shape at one end either of the oth If this series indicates pin one Once pin 1 has er two connec Wei e You can experiment with the val been identified pins are numbered tions to make an ues of R1 R2 and 1 as the values 1 to 16 going anticlockwise on off switch MM not critical provided the LEDs flash very fast when 52 is pressed However R1 should not be less than 1kQ e Note that it does not matter which way you read the LEDs left to right as on the diagram or right to left pro vided players agree which end of the row is to be six Next Month Components needed Integrated circuits 161 IC2 type 555 timer 161 type 4017 decade counter 12 Light emitting diodes LED1 to LED6 any colour Suggest LED6 is a jumbo type Resistors R1 to

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