EPE 2007-01

BALANCED MICROPHONE PREAMPQ Balanced InputQ Balanced and Unbalanced OutputsQ 3-Band EqualiserQ Ground Lift

JUMPING SPIDERSimple novel fun project

CHARGER FOR DEEP-CYCLE 12V BATTERIES Part 1A 16A, 3-step PIC controlled design

$6.95 US $8.99 CANJAN 2007 PRINTED IN THE UK

Copyright 2006, Wimborne Publishing Ltd (408 Wimborne Road East, Ferndown, Dorset, BH22 9ND, 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 materials 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.

BULL GROUP LTDUNIT D HENFIELD BUSINESS PARK

HENFIELD SUSSEX BN5 9SLTERMS: C/ CARDS, CASH, PO, CHEQUE OR

ONLINE ORDERING. PRICES PLUS VAT

UK DELIVERY 5.50

TEL 0870 7707520 FAX 01273 491813

[email protected]

HB7 Stirling Engine

Base measurements: 128 mm x 108 mm x 170 mm, 1 kg

Base plate: beech - Working rpm: 2000 rpm/min. (the

engine has a aluminium good cooling Cylinder)

Bearing application: 10 high-class ball-bearings

Material: screw, side parts all stainless steel

Cylinder brass, Rest aluminium and stainless steel.

Available as a kit 80.75 or built 84.99

www.mamodspares.co.uk

HB9 Stirling engine

Base measurements: 156 mm x 108 mm x 130 mm, 0,6

Kg Base plate: beech Working rpm: approx. 2,000 min


Material of the engine: brass, aluminium, stainless steel

running time: 30-45 min.



HB10 Stirling Engine


Kg Base plate: beech Working rpm: approx. 2,000 rpm


Material of the engine: brass, aluminium, stainless steel

running time: 30-45 min





Kg Base plate: beech

Working rpm: 2000 - 2500 rpm/min,run Bearing applica-

tion: 4 high-class ball-bearings Material: screw, side parts

total stainless steel Cylinder brass Rest aluminium, stain-

less steel.




Base measurements: 156 mm x 108 mm x 130 mm, 1 Kg

Base plate: beech Working rpm: 2000 - 2500

rpm/min,Bearing application: 6 high-class ball-bearings

Material: screw, side parts total stainless steel

Cylinder brass Rest aluminium, stainless steel.

Available as a kit 136 or built 140.25




kg Base plate: beech Working rpm: 2000 - 2500 rpm/min,

Bearing application: 6 high-class ball-bearings Material:

screw, side parts total stainless steel Cylinder brass


Everything in the kit enables you to build a fully functional

model steam engine. The main material is brass and the

finished machine demonstrates the principle of oscillation.

The boiler, uses solid fuel tablets, and is quite safe. All

critical parts (boiler, end caps, safety vent etc.) are ready

finished to ensure success. The very detailed instruction

booklet (25 pages) makes completion of this project pos-

sible in a step by step manner. Among the techniques

experienced are silver soldering, folding, drilling, fitting

and testing. 29.70 ref STEAMKIT Silver solder/flux pack

3.50 ref SSK


STEAM ENGINE KIT



Base plate: beech Working rpm: 2000 - 2500 rpm/min, .

Incl. drive-pulley for external drives Bearing application:

10 high-class ball-bearings Material: screw, side parts total

stainless steelCylinder brass Rest aluminium, stainless

steel Available as a kit 140.25 or built 144.50




kg Base plate: beech Working rpm: 2000 rpm/min. (the




Cylinder brass Rest aluminium, stainless steel

Available as a kit 97.75 or built 102




Base plate: beech Working rpm: 2000 rpm/min. (the




Cylinder brass Rest aluminium, stainless steel.


2kW WIND TURBINE KIT

The 2kW wind turbine is sup-

plied as the following kit: turbine

generator 48v three taper/

twisted fibreglass blades & hub

8m tower (four x 2m sections)

guylines / anchors / tensioners /

clamps foundation steel rectifier

2kW inverter heavy-duty pivot

tower. 1,499

Solar Panels

We stock a range of solar photovoltaic panels. These are

polycrystalline panels made from wafers of silicon lami-

nated between an impact-resistant transparent cover and

an EVA rear mounting plate. They are constructed with a

lightweight anodised aluminium frame which is predrilled

for linking to other frames/roof mounting structure, and

contain waterproof electrical terminal box on the rear. 5

watt panel 29 ref 5wnav 20 watt panel 99 ref 20wnav

60 watt panel 249 ref 60wnav. Suitable regulator for up

to 60 watt panel 20 ref REGNAV

Solar evacuated tube panels

(20 tube shown) These top-of-the-range solar panel

heat collectors are suitable for heating domestic hot

water, swimming pools etc - even in the winter! One unit

is adequate for an average household (3-4people), and

it is modular, so you can add more if required. A single

panel is sufficient for a 200 litre cylinder, but you can fit

2 or more for high water usage, or for heating swimming

pools or underfloor heating. Some types of renewable

energy are only available in certain locations, however

free solar heating is potentially available to almost every

house in the UK! Every house should have one -really!

And with an overall efficiency of almost 80%, they are

much more efficient than electric photovoltaic solar pan-

els (efficiency of 7-15%). Available in 10, 20 and 30 tube

versions. 10 tube 199, 20 tube 369, 30 tube 549.

Roof mounting kits (10/20 tubes) 12.50, 30 tube

mounting kit 15

BENCH PSU 0-15V 0-2a Output

and voltage are both smooth

and can be regulated according

to work, Input 230V, 21/2-num-

ber LCD display for voltage and

current, Robust PC-grey hous-

ing Size 13x15x21cm, Weight

3,2kg 48 REF trans2

NEW ELECTRONIC CONSTRUCTION KITS

This 30 in 1 electronic kit includes an introduction to elec-

trical and electronic technology. It provides conponents

that can be used to make a variety of experiments includ-

ing Timers and Burglar Alarms. Requires: 3 x AA batter-

ies. 15.00 ref BET1803

AM/FM Radio This kit enables you to learn about elec-

tronics and also put this knowledge into practice so you

can see and hear the effects. Includes manual with

explanations about the components and the electronic

principles. Reqs: 3 x AA batts. 13 ref BET1801

This 40 in 1 electronic kit includes an introduction to

electrical and electronic technology. It provides conpo-

nents that can be used in making basic digital logic cir-

cuits, then progresses to using Integrated circuits to

make and test a variety of digital circuits, including Flip

Flops and Counters. Reqs: 4 x AA batteries. 17 ref

BET1804

The 75 in 1 electronic kit includes an nintroduction to

electrical and electronic technology. It provides conpo-

nents that can be used to make and test a wide variety of

experiments including Water Sensors, Logic Circuits and

Oscillators. The kit then progresses to the use of an inter-

grated circuit to produce digital voice and sound record-

ing experiments such as Morning Call and Burglar Alarm.

Requires: 3 x AA batteries. 20 ref BET1806

www.slips.co.uk

ISSN 0262 3617PROJECTS . . . THEORY . . .

NEWS . . . COMMENT . . .POPULAR FEATURES . . .

VOL. 36. No. 1 JANUARY 2007

Everyday Practical Electronics, January 2007 1

Wimborne Publishing Ltd 2006. Copyright in alldrawings, photographs and articles published inEVERYDAY PRACTICAL ELECTRONICS is fullyprotected, and reproduction or imitations in whole orin part are expressly forbidden.

Our February 2007 issue will be published on Thursday,11 January 2007, see page 72 for details.

www.epemag.co.ukEPE Online: www.epemag.com

Projects and CircuitsProjects and CircuitsBBAALLAANNCCEEDD MMIICCRROOPPHHOONNEE PPRREEAAMMPP by John Clarke 10Suitable for PA, Karaoke and many other applications

JJUUMMPPIINNGG SSPPIIDDEERR by Thomas Scarborough 22Easy-to-build fun projectHHIIGGHH EEFFFFIICCIIEENNCCYY PPOOWWEERR SSUUPPPPLLYY FFOORR 11WW LLUUXXEEOONN SSTTAARR LLEEDDSS 38by Peter SmithUses a pair of D cells and includes a brightness control

IINNGGEENNUUIITTYY UUNNLLIIMMIITTEEDD Sharing your ideas with others 50Short-Range Radio Control

CCHHAARRGGEERR FFOORR DDEEEEPP -- CCYYCCLLEE 1122VV BBAATTTTEERRIIEESS PPAARRTT 11 by John Clarke 52A 16A, 3-step PIC controlled design

Series and FeaturesSeries and FeaturesTTEECCHHNNOO TTAALLKK by Mark Nelson 17Lucky Strike?

PPIICC NN MMIIXX by Keith Anderson 20Implementing a software PLL for serious users of PICs Part 1

PPRRAACCTTIICCAALLLLYY SSPPEEAAKKIINNGG by Robert Penfold 26Mounting circuit boards

CC FFOORR PPIICCss PPaarrtt 33 by Mike Hibbett 28Cross-compiling a C program

CCIIRRCCUUIITT SSUURRGGEERRYY By Ian Bell 46Understanding power MOSFETs

NNEETT WWOORRKK TTHHEE IINNTTEERRNNEETT PPAAGGEE surfed by Alan Winstanley 62Better Browsing

Regulars and ServicesRegulars and ServicesEEDDIITTOORRIIAALL 7

NNEEWWSS Barry Fox highlights technologys leading edge 8Plus everyday news from the world of electronics

CCDD--RROOMMSS FFOORR EELLEECCTTRROONNIICCSS 34A wide range of CD-ROMs for hobbyists, students and engineers

RREEAADDOOUUTT John Becker addresses general points arising 64

DDIIRREECCTT BBOOOOKK SSEERRVVIICCEE 66A wide range of technical books available by mail order, plus more CD-ROMs

EEPPEE PPCCBB SSEERRVVIICCEE 70PCBs for EPE projectsAADDVVEERRTTIISSEERRSS IINNDDEEXX 7722

INCORPORATING ELECTRONICS TODAY INTERNATIONAL

SeasonsGreetings

to all our readers and advertisers

30 in ONE - 15.95 Order Code EPL030KT




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We have some fantastic gift ideas for young (and older) enquiring mindsWe have some fantastic gift ideas for young (and older) enquiring mindsWe have some fantastic gift ideas for young (and older) enquiring mindsWe have some fantastic gift ideas for young (and older) enquiring minds

Robot Sensor - 19.95 Order Code EPLR20KT

Digital RecordingLaboratory - 29.95 Order Code EPLDRKT

AM-FM Radio Kit - 6.95 Order Code ERKAFKT

Short Wave Kit - 6.95 Order Code ERKSWKT

Crystal Radio Kit - 6.95 Order Code ERKCKT

Electronic Project LabsAn electronics coursein a box! All assume no previous knowledge and require NO solder.See website for fulldetails

Electronic Bell - 8.95 Order Code EAKEBKT

Electronic Motor - 8.95 Order Code EAKEMKT

Generator - 8.95 Order Code EAKEGKT

Room Alarm - 4.95 Order Code EAKRAKT

Hand Held Metal Detector - 9.95 Order Code ELMDX7KT

Metal Detector - 9.95 Order Code ELMDKT

Automech - 12.95 Order Code C21-605KT

Coptermech - 12.95 Order Code C21-604KT

Trainmech - 12.95 Order Code C21-606KT

Hexapod Monster Robomech - 17.95 Order Code C21-883KT(soldering required)

Stegomech - 12.95 Order Code C21-602KT

Tyrannomech - 12.95 Order Code C21-601KT

Musical LED JingleBells - 17.95 Order Code 1176KT

Flashing LED Christ-mas Tree - 6.95 Order Code 4080KT

Solderless Electronic Project Kits

MechanicalMotorisedWooden KitsFuture engineers can learn about the opera-tion of transmissions steered through gears or pulleys. Easy tobuild, no glue or sol-dering required.

Festive Fun Electronic Project Kits250 different educa-tional electronic kits. Soldering is required.

See our website for even more

great gift ideas!

Quasar Electronics Limited PO Box 6935, Bishops Stortford CM23 4WP, United KingdomTel: 0870 246 1826 Fax: 0870 460 1045 E-mail: [email protected]: www.QuasarElectronics.com

All prices INCLUDE 17.5% VAT.Postage & 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).!Order online for reduced price UK Postage!Payment: We accept all major credit/debit cards. Make cheques/POspayable to Quasar Electronics.Call now for our FREE CATALOGUE with details of over 300 kits, projects, modules and publications. Discounts for bulk quantities.

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Secure Online Ordering Facilities Full Product Listing, Descriptions & Photos Kit Documentation & Software Downloads

Moon Walker - 34.95 Order Code 4015KT

Hyper Peppy - 29.95 Order Code 4016KT

Robotic Arm - 59.95 Order Code 4017KT

Sumo Man - 59.95 Order Code 4019KT

P!mot Advanced Robot- our most advancedrobot to date (please see our website for fulldetails) - 99.95 Order Code 4026KT

Secure Online Ordering Facilities Full Product Listing, Descriptions & Photos Kit Documentation & Software Downloads

Get Plugged In!

Soldering Set - 9.95 Order Code SOL939

Hobby Tool Set - 17.95 Order Code HTK300

20 Piece ElectronicsTool Set - Now 24.95 Order Code HTK368

5 Illuminated Magnifier- 44.95 Order Code HTM015

48W Digital SolderingStation - 59.95 Order Code SOL050

3-12V 1.5A PSU - 19.95 Order Code PSU400

Robot KitsThese educationalelectronic robot kitsmake a great introduc-tion to the excitingworld of robotics and require NO soldering.See website for details

0-30V/0-3A RegulatedPower Supply - 89.95 Order Code PSU676

Hobby DMM - 5.95 Order Code MM006

Clamp Meter - 14.95 Order Code MC616

Helping Hands - 6.95 Order Code HTS165

Ultrasonic Distance Measurer - 24.95 Order Code UDM634

Universal BatteryTester - 4.95 Order Code UBT393

12V 150W PowerInverter - 29.95 Order Code RPI530

Metal Detector - 34.95 Order Code MDS920

120mm RechargeableSpotlight - 18.95 Order Code TOR260

Deluxe MicroscopeSet - 26.95 Order Code SCI284

4 in 1 PC LinkTelescope - Now 99.95 Order Code SCI293

4-ch Sequencer - 49.95 Order Code ELT298

Snow Machine - 99.95 Order Code ELT598

2x200W Car Booster Amplifier - 79.95 Order Code AMP022

20W Guitar Amplifierwith Overdrive - 69.95 Order Code MUS033

Multi-Band Radio Receiver - 24.95 Order Code RAD4997

Audio/Video Transmis-sion System - 54.95 Order Code AVE125

Tools &Equipment

Home and Leisure

1kV/500V Insulation Tester

EPETEACH-IN 2004COMPLETE 12 PARTSERIES FROM NOV03All parts to follow thisEducational ElectronicsCourse. Inc. Bread-board, and wire, aslisted on p752 Nov 03KIT920..29.99

Additional Parts aslisted in misc. Sec-tion(less RF modules,Lock, and Motor/g.box)

KIT921.12.99Reprints 1.00 per

part.

EPEPIC Toolkit 3As in EPE Apr/May/Jun 03 and on PIC Resources CD

Magenta Designed Toolkit 3 board with printed com-ponent layout, green solder mask, places for 8,18, 28(wide and slim), and 40 pin PICs. and many Magentaextras. Also runs with WinPic800 prog. Software. 16 x 2 LCD, PIC chip all parts and sockets included.

Follow John Beckers excellent PIC tutorial 2 series.

www.magenta2000.co.uk Tel: 01283 565435 Fax: 01283 546932 email: [email protected]

20W Stereo Amp.

KIT 914 ...... 11.90(includes all parts & heatsink for stereo or mono)

EPE May 05 -- Magenta Stereo/Mono ModuleWide band Lowdistortion 11W /channel Stereo20W Mono. True(rms) Real Power

Short Circuit &Overheat Protect-ed. Needs 8 to 18Vsupply.Latest Technology - Stable, Reliable, highperformance IC with local feedback.

BrainiBorg

KIT 912 ... 29.99KIT 913 ... 38.95

BrainiBorg comes withPC software CD(WIN95+& XP)with illustrated con-struction details, and canbe programmed to walkand respond to light andobstacles on any smoothsurface.

Kit includes all hardware, components, & 3 motor/gearboxes.Uses 4 AA batteries (not supplied).

A super walking programmable robot witheyes that sense obstacles and daylight.

(Kit with CD Rom &Serial Lead)(As 912 but Built &Tested Circuit board)

(With 16F84Chip)KIT 880 ...34.99

KIT 880 ... (With 16F877Chip)39.99OR - Built & Tested 49.99 & 55.99

E L E C T R O N I C S L T D 135 Hunter Street Burton on TrentStaffs DE14 2ST UK

MAGENTA BRAINIBOT I & II

KIT910..16.99KIT911..24.99

Full kit with ALL hard-ware and electronics.

As featured inEPEFeb03 (KIT 910)

Seeks light, beeps, andavoids obstacles

Spins and reverseswhen cornered

Uses 8 pin PIC chipALSO KIT 911 - As 910PLUSprogrammablefrom PC serial portleads and software CDincluded.

ICEBREAKER

KIT 900..34.99

PIC Real TimeIn-Circuit EmulatorWith serial lead & software disk, PCB, Breadboard,

PIC16F877, LCD, all components and patch leads.

PSU 3.99 Featured inEPE Mar00

Ideal for beginners &experienced users. Win-dows (95 to XP) Soft-ware included

ICEbreaker uses PIC16F877 in-circuit debugger functions.

SUPER PIC PROGRAMMERMagentas original parallel port programmer. Runs withdownloaded WINDOWS 95 - XP software. Use standardMicrochip .HEX files. Read/Prog/Verify wide range of18,28,and 40 pin PICs. Including 16F84/876/877, 627/8, (Inc.A versions) + 16xx OTPs.

KIT 862. 29.99Power Supply 3.99

From Aug/Sept.99EPE.Featuring 8 analogue inputs andserial data transfer to PC.Magenta redesigned PCB - LCDplugs directly onto board. Use as Data Loggeroras a testbed for developing other PIC16F877 projects. Kit includeslcd, programmed chip, PCB, Case, all partsand 8 x 256kEEPROMs

8 CHANNEL DATA LOGGER

KIT 877.........49.95

PIC STEPPING MOTOR DRIVERPCB with components and PIC16F84 programmed with dem-onstration software to drive any 4 phase unipolar motor up to24 Volts at 1 Amp.Kit includes 100 Step Hybrid SteppingMotor Full software source code supplied on disc. Use thisproject to develop your own applications. PCB allows simplePIC programmer SEND software to be used to reprogramchip. KIT 863.........18.99

PIC LCD DISPLAY DRIVER

KIT 860.19.99

16 Character x 2 Line dis-play, pcb, programmedPIC16F84, software disk andall components to experimentwith standard intelligent al-phanumeric displays. In-cludes full PIC source codewhich can be changed tomatch your application.

Learn how to drive the dis-play and write your owncode.

Ideal development base formeters, calculators,counters, timers --- justwaiting for your application

Top quality display withindustry standard driver,data and instructions

12V EPROM ERASERA safe low cost eraser for up to 4 EPROMS or other UVerasable windowed devices at a time in 20 minutes.Operates from a 12 Volt supply (400mA). Ideal for mobilework -and in educational applications where mains voltagesare to be avoided. Safety interlock prevents contact with UV.

KIT 790 ..... 29.90

PIC PIPE DESCALER SIMPLE TO BUILD SWEPT FREQUENCY OUTPUT HIGH POWER AUDIO & VISUAL MONITORING

An affordable circuit which sweeps theincoming water supply with varyingfrequency electromagnetic signals.May reduce scale formation, dissolveexisting scale and improve the waysalts in the water behave.Kit includes case PCB coupling coiland all components.High coil current ensures maximumeffect. LED and piezo monitor.

KIT 868 .. 22.95 PSU 3.99

PIC WATERDESCALER

EPE PROJECT PICsProgrammed PICs for EPE Projects

12C508/9-3.90; 16F627/8 - 4.9016F84/71/ - 5.90

16F876/877/ 18Fxxxx - 10.00All inc. VAT and Postage

KIT 848...32.95

Super design. Regulatedoutput and efficient cir-cuit. Dual scale meter,compact case. Reads upto 200 Megohms.Kit includes wound ferritetransformer, drilled andpunched case, meterscale, PCB & ALL compo-nents. (Needs PP3 bat-tery).

DUAL OUTPUTTENS UNITAn excellent kit for this project based on the EPE March97Design. Our Full Kit includes all components, hardware andan improved Magenta pcb. All hardware and electrodes areincluded. Designed for simple assembly and testing, provid-ing a high level controlled dual output drive.

KIT 866 .. 32.90Inc. 4 electrodes

Set of 4 SpareElectrodes 6.50

EPE MICROCHIP P.I.Treasure Hunter

Stable Sensitive Pulse Induction detector. Easy to build anduse. No ground effect - works in sea water. Detects GoldSilver, ferrous and non ferrous metals.

KIT 847 ... 63.95Kit Includes Head-phones, coil and

all Hardware

Stepping & DC Motors

MD100 100 step Unipolar..... 9.99MD200 200 step Unipolar..... 12.99MD24 Type 23 size 200 step..22.95

A range of motors for many applications:Visit our website for more details

Ultrasonic PEsT ScarersTwo Ultrasonic PEsT Scarers.Kit 812 produces regular highlevel pulses of 32kHz. Kit 867 produces Random pulses andcan work with an optional slave unit to give two separateultrasound sources. Both kits need 9V supply.

Kit 812 ... 14.81psu. 3.99Kit 867 ... 19.99 867Slave 12.51

MOSFET MKII Bench PSU0-25V 2.5A

Based on Mk1 design, withswitching pre-regulator forhigh efficiency. Panel metersfor A and V. Toroidal trans-former. Variable Volts 0 - 25AND Variable Current limitfrom 0 -2.5AKit includes punched and la-belled case. A classic andessential piece of test gear

Kit 845 ... 64.9568000 Trainer Kit 621.. 99.95

All Prices Include VAT, Add 3.00 P&P perorder, or 7.99 for next day.Chqs. P.O. & Most major cards accepted.See our Website for many more kits, prod-ucts, & Secure On Line ordering.Mail Order Only.

BAT DETECTORSMagentas Super Heterodyne Bat detectors. Our best sellingkit 861 now includes a drilled case and front panel label.The MkIIb and digital MkIII are supplied built & ready to go

KIT 861 .. 37.99MkIIb .. 49.95 MkIII .. 89.95

Soft Zip Up Pouchfor all 3....5.99

Prices Exclude Vat @17%.UK Carriage 2.50 (less than 1kg)

5.50 greater than 1kgCheques / Postal orders payable to

ESR Electronic Components.PLEASE ADD CARRIAGE & VAT TO ALL ORDERS

www.esr.co.uk

Station RoadCullercoatsTyne & WearNE30 4PQ

Tel: 0191 2514363Fax: 0191 [email protected]

4000 Series4000B 0.274001B 0.164002B 0.194008B 0.234009UB 0.234010B 0.234011B 0.164012B 0.164013B 0.184014B 0.304015B 0.274016B 0.204017B 0.204018B 0.294019B 0.254020B 0.254021B 0.314022B 0.324023B 0.234024B 0.224025B 0.204026B 0.674027B 0.214028B 0.214029B 0.384030B 0.174035B 0.314040B 0.194041B 0.314042B 0.194043B 0.354044B 0.354046B 0.354047B 0.244048B 0.344049B 0.294049UB 0.174050B 0.204051B 0.234052B 0.324053B 0.224054B 0.564055B 0.344060B 0.164063B 0.414066B 0.184067B 2.204068B 0.194069UB 0.174070B 0.154071B 0.204072B 0.184073B 0.174075B 0.174076B 0.304077B 0.284078B 0.304081B 0.164082B 0.214085B 0.284086B 0.334093B 0.164094B 0.294098B 0.224099B 0.354502B 0.324503B 0.404508B 1.404510B 0.454511B 0.304512B 0.274515B 0.994516B 0.444518B 0.264520B 0.344521B 0.624526B 0.404527B 0.404529B 0.444532B 0.244536B 1.004538B 0.404541B 0.334543B 0.474555B 0.324556B 0.404584B 0.274585B 0.474724B 0.9440106B 0.1940109B 0.5840174B 0.4640175B 0.4174HC Series74HC00 0.1674HC02 0.1774HC03 0.2174HC04 0.1474HC08 0.1674HC10 0.2174HC11 0.2174HC14 0.1874HC20 0.2874HC27 0.1674HC30 0.2274HC32 0.1474HC42 0.3674HC73 0.4074HC74 0.1574HC75 0.3174HC85 0.2374HC86 0.2174HC107 0.4074HC123 0.3374HC125 0.2674HC126 0.4674HC132 0.2674HC133 0.3474HC137 0.3074HC138 0.2674HC139 0.3174HC151 0.33

74HC153 0.3074HC154 0.9474HC157 0.2274HC158 0.2374HC160 0.6474HC161 0.2774HC162 0.4574HC163 0.2674HC164 0.2374HC165 0.2174HC173 0.3874HC174 0.2774HC175 0.3574HC193 0.3974HC195 0.3274HC240 0.3274HC241 0.3774HC244 0.4074HC245 0.3474HC251 0.3074HC253 0.2574HC257 0.2574HC259 0.2974HC273 0.3274HC299 0.6174HC365 0.2874HC367 0.3874HC368 0.2974HC373 0.3574HC374 0.3474HC390 0.5274HC393 0.3674HC563 0.5674HC573 0.2774HC574 0.3074HC595 0.2774HC597 0.2274HC688 0.4674HC4002 0.3174HC4017 0.3674HC4020 0.3674HC4040 0.2974HC4049 0.3174HC4051 0.5074HC4052 0.3474HC4053 0.2274HC4060 0.2374HC4075 0.2774HC4078 0.3274HC4511 0.6474HC4514 0.8474HC4538 0.4174HC4543 0.9074LS Series74LS00 0.3874LS01 0.1474LS02 0.2274LS03 0.2974LS04 0.3074LS05 0.1474LS08 0.1974LS09 0.1574LS10 0.2774LS11 0.1774LS12 0.2574LS14 0.3374LS15 0.2474LS20 0.2774LS21 0.2074LS26 0.1774LS27 0.2574LS30 0.2074LS32 0.2374LS37 0.3174LS38 0.1874LS40 0.1474LS51 0.2474LS73 0.3674LS75 0.3074LS83 0.3874LS85 0.4874LS86 0.2574LS92 0.4574LS93 0.5874LS107 0.3074LS109 0.2174LS112 0.2474LS113 0.2374LS114 0.3674LS122 0.3174LS123 0.3174LS125 0.2874LS126 0.2574LS132 0.4774LS133 0.3674LS136 0.2374LS138 0.3374LS139 0.2674LS145 0.5674LS148 0.6474LS151 0.2974LS153 0.3874LS156 0.3674LS157 0.2274LS158 0.2174LS160 0.4874LS161 0.3274LS162 0.4474LS163 0.3274LS164 0.4374LS165 0.4874LS173 0.2474LS174 0.2474LS175 0.3074LS190 0.6074LS191 0.2774LS192 0.6074LS193 0.4374LS195 0.2474LS221 0.4174LS240 0.3274LS241 0.3274LS243 0.30

74LS244 0.4174LS245 0.4574LS247 0.6074LS251 0.2474LS257 0.2474LS258 0.2474LS266 0.1474LS273 0.3274LS279 0.2474LS283 0.4774LS365 0.2174LS367 0.2174LS368 0.2174LS373 0.3974LS374 0.3874LS378 0.6274LS390 0.3474LS393 0.3374LS395 0.26

Linear ICsAD524AD 23.04AD548JN 2.48AD590JH 5.28AD595AQ 13.92AD620AN 9.88AD625JN 16.20AD633JN 5.92AD648JN 2.57AD654JN 5.51AD711JN 1.97AD712JN 2.51AD736JN 5.80AD797AN 7.25AD811N 5.50AD812AN 6.32AD820AN 3.41AD822AN 5.20AD829JN 6.41AD830AN 5.44AD847JN 5.95AD9696KN 7.73ADEL2020A 5.06ADM222AH 3.55ADM232AA 3.55ADM485JN 2.97ADM666AN 2.72ADM690AN 5.13ADM691AN 6.48ADM695AN 6.48ADM699AN 3.58CA3046 0.65CA3130E 0.87CA3140E 0.63CA3240E 0.91DG211CJ 1.25DG411DJ 2.00ICL7106CPL 2.21ICL7107CPL 2.06ICL7109CLP 5.76ICL7611DCP 1.00ICL7621 0.84ICL7660SCP 0.80ICM7555 0.41ICM7556 1.04L165V 2.36L272M 1.21L293E 4.20L297 5.12L298N 6.67L4960 2.81L6219 4.48LF347N 0.46LF351N 0.44LF353N 0.40LF356 0.52LM311N8 0.17LM319N14 0.90LM324 0.20LM335Z 1.12LM339N 0.19LM348N 0.36LM35DZ 0.76LM358N 0.13LM380N 0.90LM386 0.45LM392N 0.79LM393N 0.21LM1881 2.90LM2901N 0.15LM2917N8 1.98LM3900N 0.72LM3914 1.97LM3915 2.24LM13700 1.35LMC660CN 1.26LMC6032IN 1.55LP311N 0.74LP324N 0.75LP339N 0.75LT1013CN8 4.64M34-1 0.30M34-2 0.30MAX202CPE 2.00MAX208CN 6.99MAX220CPE 5.06MAX222CPE 5.06MAX232CPE 1.30MAX483CP 3.13MAX485CP 2.04MAX631ACP 4.99MAX635ACP 4.99MAX1232CP 2.80MC1458N 0.27MC1488 0.40MC1489 0.35MC3302 0.56MC4558P 0.40MK484 0.66NE521N 6.39NE555N 0.16NE556N 0.24NE565N 2.30NE592 0.62

NE5532N 0.48NE5534N 0.54NE5539N 4.35OP07CN 0.80OP27CN 2.33OP90GP 2.91OP97FP 1.84OP113GP 3.44OP176GP 2.09OP177GP 2.18OP200GP 5.60OP213FP 5.20OP275GP 2.57OP282GP 2.27OP283GP 5.20OP290GP 4.28OP297GP 4.64OP400GP 11.81OP495GP 8.69RC4136 1.00SG3524N 0.82SG3543 6.88SSM2141P 3.21SSM2142P 6.16SSM2143P 3.78TBA120S 1.04TBA800 0.75TBA810S 0.64TBA820M 0.53TDA1170S 4.80TDA2004 2.24TDA2030AV 1.24TDA2050V 2.51TDA2611A 1.88TDA2822A 0.79TDA2653A 2.99TED3718DP 5.03TEA5115 3.11TL061CP 0.37TL062CP 0.60TL064CN 0.29TL071CN 0.30TL072CN 0.40TL074CN 0.25TL081 0.28TL082CN 0.32TL084CN 0.37TL7705ACP 0.82TLC271 0.63TS272CN 0.57TS274CN 0.50TS555CN 0.40TMP01FP 5.60UA741CN 0.18ULN2003A 0.38ULN2004A 0.44ULN2803A 0.42ULN2804A 0.41

74 Series7407 0.40

RAMGM76C88. 3.60

EPROMs24LC08BP 0.7324LC16BP 0.6924LC32AP 1.1427128-200 3.9927256-200 3.9927C64A-15F 2.8027C256B-15F3.0027C512-15F12.8527C1001-15. 3.1727C2001-15. 4.4127C4001-10F5.9893C46N 0.33

A/D ConvertersData Acquisi-tionAD420AN 25.38AD7528JN 11.42AD7545AK 14.04AD7828KN 20.33DAC0800 2.40ICL7109CPL 7.75uControllersAT89C2051 6.38PIC Series12C508A04P 0.7812C509A04P 0.8316C54C04P 1.4916C54BJW 7.6016C56A-04P 1.6316F84-04P 3.1416F84-10P 3.7616F627-04P 1.5316F627-20IP 1.8017F628-20IP 2.5816F867-04SP 5.1016F877-20P 5.79

Diodes1N914 0.051N916 0.051N4001 0.051N4002 0.051N4003 0.031N4004 0.041N4005 0.041N4006 0.041N4007 0.031N4148 0.031N4149 0.071N5400 0.081N5401 0.081N5402 0.081N5404 0.091N5406 0.101N5407 0.101N5408 0.106A05 0.276A1 0.306A2 0.276A4 0.286A6 0.326A8 0.306A10 0.35BA157 0.07BA158 0.08BA159 0.13BAT41 0.12BAT42 0.07BAT46 0.12BAT85 0.09BAV21 0.07BAW62 0.07BAX16 0.05BY127 0.18BY133 0.10OA47 0.70OA90 0.33OA91 0.32OA200 0.56UF4001 0.08UF4002 0.08UF4003 0.09UF4004 0.08UF4005 0.10UF4006 0.10UF4007 0.14Zeners 2.7 to 33V500mW 0.061.3W 0.10

VoltageRegulators7805 0.277806 0.297808 0.277812 0.207815 0.2778L05 0.2278L06 0.3278L08 0.2278L12 0.1678L15 0.2678L24 0.3978S05 0.5378S12 0.4278S15 0.327905 0.237912 0.247915 0.227924 0.3879L05 0.2079L12 0.2679L15 0.2879L24 0.30ADM666AN 3.44L200CV 1.67

L296 4.42L387A 2.72LM2940CT5 0.75LM317LZ 0.25LM317T 0.30LM317K 2.28LM323K 2.40LM334Z 0.96LM337T 0.64LM338K 5.31LM338T 1.10LM723 0.40LP2950CZ5.0 0.72REF01CP 2.31REF195GP 3.04TL431CP 0.14

TriacsBT136-500 0.58BT136-600 0.50BT137-600 0.58BT139-500 1.00BT139-600 1.20BTA08-600B 0.84BTA08-600BW0.76BTA08-600C 0.96BTA08-600SW0.93BTA08-600TW1.10BTA12-600BW0.92BTA16-600CW1.45BTA16-600B 1.28BTA26-600B 2.78TIC206D 0.70TIC206M 0.75TIC226D 0.80TIC226M 1.00TIC246D 1.00TIC246M 1.00TIC236D 1.12ZO105DA 0.53

Thyristors2N5060 0.192N5061 0.19BT151-500R 0.65C106D1 0.36PO102AA 0.30TIC106D 0.49TIC116D 0.66TIC126D 0.77

Bridge Rectifiers1A 50V 0.351A 100V 0.321A 200V 0.391A 600V 0.401A 800V 0.431.5A 50V 0.191.5A 100V 0.111.5A 200V 0.191.5A 400V 0.201.5A 600V 0.241.5A 800V 0.261.5A 1kV 0.182A 100V 0.342A 200V 0.342A 400V 0.352A 800V 0.362A 1000V 0.453A 200V 0.343A 400V 0.403A 600V 0.333A 1000V 0.334A 100V 0.784A 200V 0.804A 400V 0.864A 600V 0.906A 100V 0.496A 200V 0.646A 400V 0.536A 600V 0.676A 800V 0.378A 100V 0.988A 200V 1.008A 400V 1.208A 600V 1.338A 1000V 1.0525A 100V 1.4725A 200V 1.5425A 400V 1.9825A 600V 1.8235A 50V 1.6735A 100V 1.5735A 200V 1.8035A 400V 1.4435A 600V 1.9035A 1000V 2.32

Transistors2N2222A 0.162N2369A 0.512N2646 1.022N2904A 0.352N2905A 0.302N2907A 0.282N3053 0.382N3054 0.852N3055 0.582N3439 0.622N3440 0.502N3702 0.092N3703 0.102N3704 0.112N3705 0.082N3771 1.442N3772 1.722N3773 2.302N3819 0.272N3903 0.112N3904 0.052N3905 0.102N3906 0.052N4401 0.082N4403 0.092N5245 0.802N5296 0.572N5401 0.122N5551 0.072N6491 1.582N7000 0.192SB548 0.30AC127 0.50AC128 0.76AC187 0.68AC188 0.97ACY17 4.84AD149 1.29AD161 0.73AD162 0.95BC107 0.15BC107B 0.14BC108 0.13BC108B 0.14BC108C 0.18BC109 0.17BC109C 0.16BC114 0.19BC115 0.41BC118 0.41BC132 0.36BC134 0.36BC135 0.36BC140 0.75BC142 0.50BC143 0.38BC159 0.17BC160 0.28BC170B 0.16BC171B 0.16BC177 0.15BC178 0.18

BC179 0.15BC182B 0.09BC182L 0.11BC183L 0.09BC184 0.09BC184L 0.12BC206B 0.72BC208 0.72BC209A 0.72BC212L 0.09BC213L 0.12BC214 0.08BC214L 0.10BC225 0.15BC237B 0.11BC238B 0.11BC250A 0.15BC261B 0.30BC262B 0.24BC267B 0.30BC319C 0.13BC327 0.08BC327-25 0.08BC328 0.09BC337-16 0.10BC337-25 0.07BC348B 0.14BC357 0.25BC393 0.73BC461 0.41BC463 0.29BC477 0.52BC479 0.32BC516 0.21BC517 0.12BC546B 0.06BC546C 0.08BC547A 0.09BC547B 0.09BC547C 0.10BC548A 0.08BC548B 0.09BC548C 0.08BC549B 0.09BC549C 0.09BC550C 0.11BC556A 0.08BC556B 0.10BC557A 0.09BC557B 0.09BC557C 0.09BC558A 0.08BC558B 0.09BC559A 0.08BC560A 0.09BC636 0.10BC637 0.19BC638 0.21BC639 0.09BC640 0.13BCY72 0.20BD124P 6.86BD131 0.48BD132 0.46BD135 0.22BD136 0.21BD137 0.23BD138 0.19BD139 0.23BD140 0.14BD150C 0.82BD201 0.40BD202 0.70BD232 0.50BD237 0.32BD238 0.44BD240C 0.37BD245C 1.10BD246C 1.18BD283 0.61BD284 0.61BD400 0.79BD437 0.17BD438 0.22BD442 0.37BD534 0.47BD535 0.50BD581 0.62BD597 0.92BD646 0.52BD648 0.52BD650 0.53BDX32 1.78BDX34C 0.45BDX53C 0.53BDX54C 0.50BF180 0.31BF182 0.31

BF245B 0.40BF257 0.33BF259 0.33BF337 0.40BF422 0.15BF423 0.15BF459 0.33BF469 0.36BFX29 0.29BFX84 0.31BFX85 0.33BFX88 0.27BFY50 0.30BFY51 0.22BFY52 0.24BS107 0.21BS170 0.15BU208A 1.53BU326A 1.40BU500 1.54BU508A 1.40BU508D 0.98BU806 1.06BUT11A 0.57BUT11AF 1.14BUX84 0.78BUZ900P 5.60BUZ905P 5.60IRF530 0.53IRF540 0.78IRF630 0.42IRF640 0.63IRF730 0.66IRF740 0.91IRF830 0.68IRF840 0.78MJ2955 0.90MJ2501 1.60MJ3001 1.84MJ11015 2.45MJ11016 2.78MJE340 0.33MJE350 0.32MPSA05 0.14MPSA13 0.09MPSA42 0.14MPSA55 0.13MPSA56 0.12STW80NE-103.80TIP29A 0.32TIP29C 0.33TIP30A 0.47TIP30C 0.27TIP31A 0.23TIP31C 0.35TIP32A 0.29TIP32C 0.30TIP33C 0.74TIP41A 0.32TIP41C 0.32TIP42A 0.47TIP42C 0.43TIP50 0.28TIP110 0.28TIP120 0.30TIP121 0.32TIP122 0.24TIP125 0.31TIP126 0.31TIP127 0.35TIP132 0.50TIP137 0.64TIP141 0.93TIP142 0.93TIP147 1.07TIP2955 0.46TIP3055 0.46ZVN2106A 0.40ZVN2110A 0.45ZVN3306A 0.28ZVN4206A 0.52ZVN4210A 0.56ZVN4306A 0.74ZVN4310A 0.88ZVP2106A 0.42ZVP2110A 0.46ZVP3306A 0.32ZTX302 0.17ZTX450 0.19ZTX451 0.19ZTX453 0.26ZTX500 0.16ZTX502 0.17ZTX550 0.22ZTX551 0.33ZTX600 0.33ZTX600B 0.35ZTX605 0.36

ZTX651 0.33ZTX653 0.37ZTX689B 0.40ZTX690B 0.37ZTX705 0.39ZTX750 0.25ZTX751 0.34ZTX753 0.40ZTX789A 0.41ZTX790A 0.41ZTX851 0.50ZTX853 0.50ZTX951 0.54ZTX1048A 0.48ZTX1051A 0.46ZTX1053A 0.45

DiacDB3, 32V 0.08

per 100 of onevalue onlyResistors - Please State Value Required

1/8W Carbon Film 5% E12 Series 10W-1M0 0.02 Each, 0.80 per 100W Carbon Film 5% E12 Series 1W-10M 0.02 Each, 0.60 per 100W Metal Film 1% E24 Series 10W-1M 0.04 Each, 1.72 per 100W Carbon Film 5% E12 Series 1W-10M 0.02 Each, 0.95 per 1002.5W Wirewound 5% E12 Series 0W1-220W 0.23 Each1W, 2W, 5W, 20W, 25W & 50W also in stock - selected values only, contact sales dept.Preset Resistors - Please State Value RequiredEnclosed, 10mm Square Horz / Vert. 100W - 1M0 0.15W 0.12 EachSkeleton, 10mm Dia. Horizontal. 100W - 1M0 0.1W 0.09 EachSub-min, 6mm Dia, Horizontal E3 200W-1M0 0.1W 0.12 EachMultiturn, 10mm Square, Top Adjust. E3 100W-1M0 0.5W 0.81 EachMultiturn, 19mm Long, End Adjust. E3 50W-1M0 0.5W 0.59 EachPotentiometers - Please State Value RequiredSingle Gang Shaft, 25mm Dia. 470W-2M2 Linear 0.56 EachSingle Gang Shaft, 25mm Dia. 4k7,10k,47k,100k,1M,2M2 Log 0.56 EachDual Gang Shaft, 20mm Dia. 1k0-2M2 Linear 1.54 EachDual Gang Shaft, 20mm Dia. 10k-470k Logarithmic 1.54 EachSwitched Shaft, 20mm Dia. 1k0-2M2 Linear 1.92 EachSwitched Shaft, 20mm Dia. 4k7-2M2 Logarithmic 1.92 EachPCB Mount, Splined Shaft, 16mm Dia. 470W-1M0 Linear 0.48 EachPCB Mount, Splined Shaft, 16mm Dia. 470W,4k7,100k,1M0 Log 0.56 EachDual PCB, Splined Shaft, 16mm Dia. 10k,50k100k,500k Lin 1.05 EachDual PCB, Splined Shaft, 16mm Dia. 10k,50k,100k,500k Log 1.00 Each

We carry a large range of capacitors in stock, including:Ceramic Mini Disc, Dipped Ceramic Multilayer, Dipped & Boxed Polyester,Mylar Film, Polystyrene, Plastic Film, MKT Polyester, Tantalum Bead, Sub-min-iature Radial, 105C Radial, Low Leakage Radial, Non Polarised Radial & Ax-ial, PCB Can Electrolytics, Polypropylene & Ceramic Trimmers and Tuningcapacitors. Full technical details available.

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VOL. 36 No. 1 JANUARY 2007

Power for the peopleOver the years we have reported on many developments of energy generation, from wind

and wave power to nuclear fusion. As yet, only wind power seems to have come of age andis now providing energy to the national grid.

We first reported on experimental wave power systems back in the September 78 issue ofPE, so that seems to have taken an age to come to fruition. Similarly with nuclear fusion,which is perhaps the most exciting prospect and one that could provide all the worlds ener-gy needs in the future, without most of the potential problems associated with the presentnuclear reactors, waste disposal etc.

Worldwide research and a great deal of collaboration has been lavished on fusion experi-ents; the Joint European Torus (JET) project was set up in 1978 to construct and operate afusion facility at Culham in Oxfordshire. (There is a facility for visitors and educational par-ties to view the project see the JET website for details.) JET started operating in 1983 andwas the first fusion facility to achieve significant production of controlled fusion power in 1991.

As we go to press the ITER Agreement has been signed in France, this is a joint interna-tional research and development project to demonstrate the feasibility of fusion power. ITERwill be built at Cadarache in the South of France as a joint venture between the EuropeanUnion, Japan, China, India, Korea, Russia and the USA. (ITER originally stood forInternational Thermonuclear Experimental Reactor, but that title was dropped to avoid anynegative connotations ITER also means the way in Latin.) The aim is to be able to deploythe first generation of fusion power plants to deliver power to the grid by 2050.

The new facility will commence construction in 2008, with assembly of the ITER deviceitself scheduled to begin in 2011. The overall cost is estimated to be 10 billion Euros (about$12 billion US), a figure that seems low in comparison with the escalating cost of the 2012London Olympics and the annual cost of electricity in the USA alone of $210 billion.

Provided prolonged fusion can be achieved and the sun can be contained in a box theproblem being the construction of the box then the world may have most of its powerrequirements serviced by fusion in 100 years time. Lets hope it is worth waiting for; ofcourse, we may run out of oil before then, so we may also need the wind and waves to help!

TTHHEE UUKKss NNoo..11 MMAAGGAAZZIINNEE FFOORR EELLEECCTTRROONNIICCSS TTEECCHHNNOOLLOOGGYY && CCOOMMPPUUTTEERR PPRROOJJEECCTTSS

HD BabelIf you think the format war between Blu-ray and HD-DVD is confusing, Barry fox

suggests you should spare a thought for the companies that must make the discs

8 Everyday Practical Electronics, January 2007

NNeewwss .. .. .. A roundup of the latestEveryday News from the worldof electronics

Emergency CollectionNow available at www.thebrandcollec-

tion.com is a range of innovative beauty,home and lifestyle products for all thefamily. These genius products bring youadvanced technology, substantiated per-formance promise and design credentialsat affordable prices. For example, theWorlds first iPod and Mobile Chargerusing regular batteries. Claimed to be des-tined to become a style icon thanks to itssmart technology and mini dimensions,this pocket-size AA battery charger isdesigned to charge your iPod withoutneeding a computer. It also chargesmobile phones, providing up to threehours of extra talk time so you wont beleft stranded with a dead phone battery.

Dyna-Brite Rescue is said to be more reli-able than Superheroes, this advanced multi-function support device for car and homeprepares you to deal with a range of emer-gencies, from a flat car battery to a powercut. Jump-start your car through the ciga-rette lighter, charge your mobile and muchmore with this all-in-one car charger, mobilephone charger, emergency siren/alarm, highpower flashlight and am/fm radio withspeakers. Portable and lightweight, it isclaimed to offer peace of mind day and nightfor women, men and families at home andon the road.

Battery-free Crank It Flashlight the firstweatherproof battery-free emergency torchis now available in the UK. Just 30 secondsof continuous cranking provides up to an

hour of superbright light. Unbeatable in arange of emergency situations and bad-weather conditions because it never needsbatteries or bulbs replaced, its shockproofand, if it falls in water, dont despair becauseit floats.

Fran OConnor, Innovation Director said,These are professional-standard emergencyaids for everday living, and also first-classcompanions for travellers and outdoor pur-suit enthusiasts. They fit with The BrandCollection ethos of providing proven, well-tested gadgets that work brilliantly and last along time offering customers real value formoney.

For all enquiries on these and other prod-ucts please call 0207 350 2020 or log on atwww.thebrandcollection.com.

PRODUCTION houses must cope witha chaos of different master tape for-mats before they can even think aboutadding interactive menus and pressingdiscs. This was the clear message to springout of two conferences held in Barcelonaby market analysts Understanding andSolutions. The first tackled the broad issueof Making HDTV Business Happen, andwas strongly supported by the Blu-raycamp, and Sony in particular.

The second event was the official confer-ence of the DVD Forum, which likes topretend that Blu-ray does not exist.Stephanie Holm, Head of Operations atNational Geographic warned: We aredealing with 17 HD standard productionand master formats, and they need stan-dards conversion. The average incrementalcost for HD productions is 13% more thanfor SD.

Michael Becker, MD of Imagion, anauthoring facility in Germany, reckons thatmastering for blue laser discs takesbetween four and six times longer than fora conventional DVD. Andy Quested,Principal HD Technologist at the BBC,reckoned there were at least 20 productionstandards for HD programming.

The BBC has not yet seen a standardsconverter, either 60-50Hz or 50-60Hz,which it can recommend. So the BBCshoots programmes like Planet Earth at 50interlaced pictures a second. RichardOsborn, of Abbey Road Interactive puts thenumber even higher: There are between17 and 25 different standards depending onhow you count them. Abbey Road has

standardized on 23.976 frames per secondfor film material instead of 24fps. This oddnumber frame rate is derived from the USNTSC standard of 59.97 to avoid harmon-ic interference at 60Hz. Other companiesare choosing 24 fps or 25 fps or 50i.

Dieter Schlautmann, Head of NewMedia Development at Sonopress inGermany reminded that there are threestandards for coding HDTV material,MPEG-2, MPEG-4 VC-1 and MPEG-4H.264; and a wide range of Dolby andDTS audio standards. Will Morley MD ofthe De Luxe authoring studios in London,says: It takes 45 hours to do two codingpasses then manual fixing, often 500manual fixes thats 20 hours extra. Aninternational disc needs 58 hours of quali-ty assurance checking. If the checkers finda problem and fix it their reward is 58 morehours of QA.A pain in the neck

All this plus the extra cost of pressing puts up the cost of authoring blue laserdiscs, to levels which only major compa-nies can afford. Their chances of gettingtheir money back are then jeopardised bythe format war between Blu-ray and HD-DVD. Consumers may just wait for the warto end before buying anything.

The conference provided a good exampleof how the Hollywood studios seem tothink that if they ignore this problem it willgo away. During a relentlessly upbeatpanel session several Hollywood studioexecutives and even Chairman Jim

Bottoms repeatedly referred to blue laseras a new format, not formats. Lateranother panel chairman, Bill Foster,remarked that some disc producers founddealing with the AACS LicensingAuthority, which controls the copy protec-tion system used by both blue laser discs,as a pain in the neck.

Laurent Villaume, President of Frenchreplicator QOL (Quantum OpticalLaboratories), agreed wholeheartedly andreminded that the studios had made the useof AACS compulsory. Every HD discmust use it. We have no choice and wehave to pay a lot of money. The licence isvery expensive. We have to pay $25,000and then we have to buy the keys for thediscs.

Masato Otsuka, Senior VP and Directorof Memory-Techs R & D Centre and DVDVerification Laboratory in Tokyo, addedOn top of the $25,000 to become a licens-ee, we have to buy an MKB group of keysfor around $400. And then we have to pay$1500 each for the Content Certificatekeys needed to code a disc. Thats $1500for each disc. And if we need to re-make adisc, even if we only make a small changein the graphics, we have to buy a new CCfor another $1500. Its too much. We needto see a reduction.

The AACS-LA website is still, aftermore than two years, only under construc-tion with the key information areas Newsand FAQ still coming soon. AACS-LAsappointed spokesman has been unable orunwilling to say when the site will containthe promised information.


CONTINUITY TESTERExtech Instruments, a supplier of test and

measurement equipment for the industrialmarketplace, has announced its new CT20Continuity Tester Pro. This extremely-affordable test product features the uniquecapability for single person operation ofwire and cable continuity checking andidentification, eliminating the need forsomeone to be at both ends of the wiresunder test. The Continuity Tester Pro is theperfect tool for electricians, cable TV andaudio systems installers, alarm technicians,HVAC installers, auto repair technicians,handymen and DIY homeowners.

The CT20 is a two-part system consistingof the master Continuity Tester/Transmitterand a unique two-lead, bicolour (red/green)

LED Remote Probe. The master ContinuityTester/Transmitter is used for local conti-nuity testing and remote wiring identifica-tion. Using the Remote Probe allows forsingle-person remote continuity testingwhen identifying cables, verifying polarityor labelling long distance wire/cable runswhere the other ends of the wires or cablesare in a completely different area out ofsight and sound.

The bright pulsating LED is visible evenin bright daylight areas. It flashes greenwhen wiring is properly identified andflashes red when wiring is reversed. Themaster Continuity Tester/Transmitter fea-tures bright flashing LEDs and a loud pul-sating beeper which can be heard over highbackground noise.

This combination of thetwo parts allows a singleuser to identify up to threewires or cables at a time forcorrect labelling, with onlyone trip to the other end ofthe wire or cable location.Lightweight and pocket-sized, both parts of theContinuity Tester Pro fea-ture alligator clips to enablethem to hang from thecable(s) under test.

The UK distributor isBurn Technology Ltd, DeptEPE, Winfrith TechnologyCentre, Dorchester DT28DH. Tel: +44 (0) 1305 852090 Fax +44 (0) 1929 463214 sales (czburntec.com).Web: www.extechinstruments.co.uk.

RAPID TOOLSCATALOGUE

Rapid Electronics have sent us an excel-lent just-over-pocket-sized booklet of thetools the company can supply. Whats in it?Well, goodness, hard to say practicallyeverything it seems, all covered in over 170pages, nicely presented in colour and withprices. We can only say get a copy!

Contact Rapid Electronics Ltd., DeptEPE, Severalls Lane, Colchester, EssexC04 5JS. Tel: 01206 751166. Fax: 01206751188. Email: [email protected],uk.Web: www.rapidonline.com.

Maplins OffersMaplin Electronics have sent a couple

brochures highlighting their special offers masses of them, too many to categorise,even though only 12 A4 pages are involved.Contact Maplin for your copy of their latestoffers info, via tel: 0870 429 6000, web:www.maplin.co.uk, or visit one of theirmany nationwide stores.

MERG AUTUMN JOURNALThe Model Electronic Railway Group

(MERG) have sent us their AutumnJournal. What a whopper! The range ofactivities is ever increasing, as is theirmembership they tell us.

We know many of you already belong toMERG, but if you are into model railwaysand dont belong yet, you should!

For more information contact JohnFerguson, Secretary MERG, 5 Butts Lane,Danbury, Essex CM3 4NP. Tel: 01245223888. Email: [email protected].

IF you have ever thought about becominga video game developer, now is yourchance. Parallax Inc. a privately held com-pany located in Rocklin, CA USA, haspartnered with Nurve Networks LLC andAndre LaMothe, best-selling game devel-opment author, to release a new Propellerpowered gaming product, the Hydra GameConsole! With the Hydra you can developgames, graphics and media applications.

For beginner to intermediate coders, youneed only basic programming experience inany Basic or C-like language. All of thehardware and software you need is included.Additionally, the Hydra hardware is coveredin detail with schematics, descriptions,dozens of games, demos, and tips allowingyou to take full advantage of its resources,including its expansion port and 128K gamecard.

The Hydra kit also comes with GameProgramming for the Propeller PoweredHydra, Andre LaMothes latest book. Thiscomprehensive book covers everythingyou need to know about game program-ming for the Propeller in Spin and assem-bly language. All aspects of the Propellerchip are introduced, from its architecture tousing the Propeller Tool for programming.

The Propeller chip was released byParallax Inc. in April of this year. The chip,designed at the transistor level, uses a newcustom-silicon design for simultaneousmulti-processing. The Propeller is a 32-bit

architecture consisting of eight processorswhich run at 33V up to 80MHz. ThePropeller is programmed in both a high-level language, called Spin T, and low-level (assembly) language.

The Hydra Game Console is available atwww.parallax.com or by calling theParallax Sales Department in the USA on1-888-512-1024. Please mention EPEwhen responding.

HYDRA VIDEO GAME DEVELOPER

Constructional Project Constructional Project Constructional Project Constructional Project

10 EverydayPracticalElectronics,January2007 EverydayPracticalElectronics,January2007 11

Main Features

Balanced input for micro-phone

Balanced and unbalanced output

Level control 3-band equaliser Runs from battery, plugpack

or phantom power

Battery indicator Ground lift Rugged diecast housing

This Balanced Microphone Preamp comes with a 3-band equaliser and is suitable for Karaoke, public address or many other applications. It can run from a plugpack, its own internal 9V battery or phantom power.

Whether it is for karaoke, public address or for a band, a microphone connection to an amplifier is a basic requirement. this Balanced Microphone Preamplifier includes a 3-band equaliser and can be used to drive a guitar amplifier, any stereo amplifier or provide an additional channel for a public address amplifier.

Balanced microphones are desirable since they prevent the injection of hum and noise into the sound system. A balanced microphone has a 3-wire cable usually connected via XLR plugs and sockets. XLR pin 1 is the return or ground and the other two terminals (pins 2 & 3) are for the signals. The signals are in anti-phase; in other words when one line goes positive, the other line swings negative by the same amount. Any hum that is picked up along the lead is effectively cancelled because the same level of hum will be present in both signal lines.

In controlThe 3-band equaliser (bass, mid and

treble controls) is handy for enhancing a musical instrument so that it sounds natural when played through the mi-crophone or to remove sibilance (the whistle sound from a voice, particular-ly when pronouncing the letter s) by reducing the treble level and boosting the mid range. or the bass control can be reduced to suppress popping noises which occur when speakers hold the microphone too close.

Balanced Microphone Preamp

by JOHN CLARKE



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Parts List Balanced Microphone Preamp

1 PC board, code 599, available from the EPE PCB Service, size 102 x 84mm

1 metal diecast box, 119 x 94 x 57mm

1 front panel label, 112 x 88mm2 SPST ultra-mini rocker

switches (S1-S2)1 momentary-contact pushbutton

switch (S3)1 PC-mount 9V battery holder1 mono 6.35mm panel-mount

jack socket (CON 2)1 3-pin male XLR panel-mount

connector (CON 3)1 3-pin female XLR panel-mount

connector (CON 1)1 2.5mm PC-mount DC socket1 PC-mount 10k 16mm log

potentiometer (VR1)3 PC-mount 100k 16mm linear

potentiometers (VR2-VR4)4 knobs to suit potentiometers4 stick-on rubber feet4 M3 tapped x 6mm Nylon spacers12 M3 x 6mm screws1 M3 x 10mm screws1 M3 nut3 M2.5 x 6mm screws1 3mm eyelet crimp connector 12 PC stakes1 200mm length green hookup

wire 1 200mm length pink hookup wire1 200mm length orange hookup

wire1 200mm length blue hookup wire1 200mm length red hookup wire1 200mm length purple hookup wire

Semiconductors2 TL072 dual op amps (IC1, IC2)1 1N5819 Schottky diode (D1)3 1N4004 diodes (D2-D4)1 12V 1W Zener diode (ZD1)1 5.6V 1W Zener diode (ZD2)1 5mm red LED (LED1)1 7812 +12V voltage regulator

(REG1)Capacitors3 100F 16V PC electrolytic1 100F 16V PC electrolytic

(optional) 2 22F 16V PC electrolytic3 10F 16V PC electrolytic2 10F 16V non-polarised (NP

or BP) electrolytic2 2.2F 16V PC electrolytic1 470nF MKT polyester1 220nF MKT polyester1 15nF MKT polyester1 12nF MKT polyester1 2.7nF MKT polyester1 1.5nF MKT polyester2 1nF MKT polyester1 330pF ceramic1 220pF ceramic1 100pF ceramic1 22pF ceramic

Resistors (0.25W 1%)2 100k 2 3.3k2 18k 1 2.2k2 12k 5 1k6 10k 1 2201 10k (optional) 3 1502 1k (optional)

A level control is included to pre-vent overload and a ground lift switch can reduce hum in some situations.

Circuit detailsLets now have a look the circuit

in Fig.1. It uses two low-cost op amp ICs, four potentiometers, an XLR socket and plug, a 6.35mm jack socket, several switches and a few other low- cost parts.

Op amp IC1a functions as a bal-anced-to-unbalanced preamplifier with a modest gain. The balanced microphone signal is fed to pins 5 & 6 of IC1a via 22F capacitors and 1k resistors. Gain for the inverting input is set at 13.3 by the 3.3k feedback

resistor from pin 7 to pin 6. Frequen-cies above 48kHz are rolled off by the 1nF capacitor across the 3.3k feedback resistor.

For the non-inverting input (pin 5), the input signal is attenuated by a factor of 0.77 due to the 3.3k resistor connecting to Vcc/2. Overall gain for this signal path is therefore 0.77 4.3 or +3.3. Thus, the signal gain for both signal paths is the same.

The 330pF capacitor between pin 2 and pin 3 of the XLR socket shunts high frequencies so that the Preampli-fier does not detect radio frequencies. The output of IC1a is fed to the Level potentiometer, VR1, via a 2.2F capaci-tor and then to pin 3 of op amp IC1b.

This provides a gain of 46 by virtue of the 100k feedback resistor between pins 1 & 2 and the 2.2k resistor to the half supply rail (Vcc/2). IC1b drives the following 3-band equaliser stage via a 2.2F capacitor.

EQ controlsThe equaliser stage is based on op

amp IC2a and potentiometers VR2, VR3 and VR4. These potentiometers and their associated resistors and capacitors are in the feedback path between pins 6 & 7.

Each of the Bass (VR2), Midrange (VR3) and Treble (VR4) feedback networks are effectively in parallel and act more or less independently (ie, with modest interaction). When the tone pots are all centred, the gain over their respective frequency ranges is unity (1) and therefore the overall frequency response is flat.

Lets now look at the Bass con-trol in more detail. When we wind the wiper of VR2 fully clockwise towards the output of IC1b, the input resistance for IC2a now decreases to 18k while the feedback resistance increases to 118k. At the same time, the 15nF capacitor is completely in the feedback circuit across the 118k resistance. Without this capacitance the gain would be 118k/18k or 6.5 (ie, +16dB boost). The addition of the capacitor forces the circuit to give this gain below 100Hz and this reduces towards 1 as the frequency increases.

Conversely, when the pots wiper is wound towards IC2a (anti-clockwise), the gain without the capacitor is 18k/118k or 0.15 (ie, 16dB cut). The 15nF capacitor is now on the input side so the gain rapidly increases to 1 at frequencies above 100Hz. Maximum bass cut is below 100Hz.

The Midrange section with VR3 works in a similar manner except that there is now a 12nF capacitor in series with the input. This combines with the 2.7nF capacitor across VR3 to give a bandpass filter.

Finally, the Treble control (VR4) operates with only a 1.5nF capacitor in series with the wiper. As a result, this control produces a high frequency boost or cut at 10kHz. Response curves for the tone controls are shown in Fig.2.

The 220pF capacitor across IC2as feedback path provides high frequency rolloff to prevent instability. Similarly,



SpecificationSensitivity ................................................................ 6.8mV input for 1V outputSignal Handling ............................................... 2.3V RMS with equaliser set to

flat response and 12V supply; 1.8V RMS at 9V supplyInput Impedance ........................................................................................ 1kFrequency Response ............................................... 3dB at 30Hz and 19kHzEqualiser Response ........................................ +11dB and 11dB boost or cut

at 100Hz; +9.6 and 10dB boost or cut at 1kHz; +7.4 and 8.4dB at 10kHz

Signal-To-Noise Ratio ........................................ 80dB with respect to 1V out and 20Hz to 20kHz bandwidth; 185dB A-weighted

Phase Difference at Balanced Outputs ............. 180 at 1kHz; 160 at 20kHzBattery Current ............................................................................. 8.8mA at 9V

the 1k resistor at the inverting input acts as a stopper for RF signals to pre-vent radio pickup.

IC2as output at pin 7 drives the unbalanced output at CON2 via a 10F capacitor and 150 resistor. IC2as output also drives pin 2 of the XLR output socket CON3, again via a 10F capacitor and 150 resistor. Also, IC2as output drives inverting amplifier IC2b. This has a gain of 11 to derive the out-of-phase signal for pin 3 of CON3.

The remaining pin on the XLR plug is the ground pin (pin 1). This is ei-ther directly connected to ground via switch S2 or AC-coupled to ground via a 470nF capacitor. Opening the ground lift switch (S2) prevents a hum loop if the input is separately earthed. This is not likely to occur with a mi-crophone but there may be separate grounds connected when the unit is used to convert a balanced line to an unbalanced output.

Power supplyPower for the circuit can come from

a DC plugpack, internal 9V battery or via phantom power. Diode D4 provides reverse polarity protection for external DC power sources such as a plugpack. The DC supply rail is then filtered and applied to 3-terminal regulator REG1 to provide the +12V rail which is then fed to IC1 and IC2 via diode D2.

The internal battery supply is fed to the op amps via Schottky diode D1. A Schottky diode has a lower voltage drop than a standard diode and this extends the battery life.

Note that the negative return of the battery goes via the DC power socket. Hence, the battery is disconnected whenever a plug is inserted into the DC power socket (CON 4).

Phantom power is delivered via pins 2 & 3 of the XLR plug and applied via two 1k resistors to diode D3. Zener diode ZD1 regulates the voltage to 12V before it is applied to the rest of the circuit. This phantom power is usu-ally produced from a source of either 48V with a 3.4k impedance or from 24V with a 600 impedance. We can draw up to 7.5mA from each supply or 15mA in total at 12V.

Diodes D1, D2 & D3 isolate each sup-ply so that only one source can deliver power to the circuit. Essentially, where more than one supply is connected, it is the highest voltage source that powers the unit.

The half-supply rail (Vcc/2) is ob- tained using two 10k resistors con-nected in series across the power supply. The half supply point is de-coupled using a 100F capacitor to filter out any supply ripple.

Switch S3, LED1, ZD2 and the series 220 resistor form a simple battery test indicator. If the voltage is 9V, the voltage across the 220 resistor will be 9V 15.1V 11.8V (the LED voltage drop) or 2.1V. As a result, a current of 9.5mA will flow through LED1 when S3 is closed. This will cause the LED to glow brightly.

Fig.2: this graph shows the responses generated by the bass, mid-range and treble controls. The maximum bass boost is 12dB at 100Hz, while maximum mid-range boost is about 9dB at 850Hz. The treble boost is limited to about 7dB at 11kHz

As the battery voltage goes down, the current through the LED drops accordingly and so its brightness also decreases. For example, a battery voltage of 7.5V will only leave about 0.6V across the 220 resistor and so just 2.7mA will flow through the LED which will then be quite dim.

Building itMost of the parts for the Balanced

Microphone Preamplifier are mounted on a PC board coded 599 measuring 102 89mm. This is housed in a metal diecast box measuring 119



Table 1: Resistor Colour Codes

o No. Value 4-Band Code (1%) 5-Band Code (1%) o 2 100k brownblackyellowbrown brownblackblackorangebrown o 2 18k browngreyorangebrown browngreyblackredbrown o 2 12k brownredorangebrown brownredblackredbrown o 4 10k brownblackorangebrown brownblackblackredbrown o 3(optional) 10k brownblackorangebrown brownblackblackredbrown o 2 3.3k orangeorangeredbrown orangeorangeblackbrownbrown o 1 2.2k redredredbrown redredblackbrownbrown o 7 1k brownblackredbrown brownblackblackbrownbrown o 1 220 redredbrownbrown redredblackblackbrown o 3 150 browngreenbrownbrown browngreenblackblackbrown

94 57mm. The diecast case serves to provide shielding for the audio circuitry and makes the unit extremely rugged a necessary requirement for stage work.

Fig.3 shows the PC board assembly details. Begin by checking the PC board for any shorts or breaks in the copper tracks. Check also that the PC board fits neatly into the case. If it doesnt, file the corners and edges of the board so that it fits when seated on 6mm standoffs. These can be

temporarily attached for testing the PC board fit. Position the PC board within the box and mark out the four corner mounting holes. Remove the PCB and put the box to one side.

Install the three wire links first, then the resistors. Note that the resistors marked with an asterisk are only used if the mi-crophone needs an external supply. Table 1 shows the resistor colour codes used in the circuit. It is wise to check each value with a digital multimeter, as the colours can be hard to recognise.

The diodes can be installed next, making sure that D1 is the 1N5819. Be careful not to mix up the two Zener diodes. ZD2 is the 5.1V Zener and may be marked 1N4732 or C5V1. ZD1 is the 12V device and will be labelled 1N4742 or C12V.

Next, install the two ICs and the capacitors. Non-polarised capacitors can be installed either way around but standard electrolytics with negative lead markings must be placed in the PC board with the correct polarity.

The DC socket and REG1 can now be installed, followed by the PC stakes. The four pots can then be mounted on the PC board.

LED1 should be installed about 20mm above the PC board. It is later bent over to mount in a hole in the side of the case. Finally, complete the PC board by installing the 9V-battery holder using three M2.5 screws. Make sure the leads are soldered to the PC board.

Drilling the boxReturning to the box. The first job

is to drill out the four corner mount-ing holes in the bottom of the case to 3mm. That done, attach the four 6mm tapped spacers to the underside of the PC board using M3 6mm screws. Note that the 6mm spacers must be nylon or insulated types to prevent the tracks on the PC board from shorting to the case.

Next, mark out the positions for the pot shafts. The shaft centres are about 22mm above the outside base of the box. Drill the holes for the pot shafts, then use a rat-tail file to elongate the holes vertically. This will make it easier to insert the pots through the holes when the final assembly is in-serted into the box.

Fig.3: install the parts on the PC board as shown here. The components marked with an asterisk are optional and are installed only if you are using a phantom powered microphone or an externally powered microphone



Table 2: Capacitor Codes

Value F Code EIA Code IEC Code 470nF 0.47F 474 470n 220nF 0.22F 224 220n 15nF 0.015F 153 15n 12nF 0.012F 123 12n 2.7nF 0.0027F 272 2n7 1.5nF 0.0015F 152 1n5 1nF 0.001F 102 1n 330pF 331 330p 220pF 221 220p 100pF 101 100p 22pF 22 22p

Now mark out and drill the mount-ing holes for the 6.35mm jack socket, the XLR connectors, the switches and the LED and DC socket. Use the pho-tographs as a guide to the positioning of these holes.

The switch cutout and XLR holes can be made by first drilling a se-ries of holes around the outside perimeter, then knocking out the centrepiece and carefully filing to shape. The switches must be a snug fit so that they will be held correctly in position with the integral plastic retaining lugs. The XLR connectors are secured with M3 6mm screws that are tapped directly into the case. We used an M3 tap to make the thread and first drilled the hole out to 3/32 (2.4mm). If you use nuts instead of tapping the hole you will find it dif-

Above: this view shows the location of the battery test switch (S3), the power socket (CON4) and the battery test indicator LED on the rear panel. Note that S3 should be a pushbutton switch, not a rocker type as shown here

Right: this end of the case carries (from left to right) the 3-pin male XLR socket (CON3), a 6.5mm jack socket (CON2), the Ground Lift switch (S2) and the Power switch (S1). The 3-pin female XLR socket mounts on the other end of the case

ficult to attach the lower nut unless it is glued in position first. Finally, drill a 3mm hole for the case earthing connection.

Now fit the PC board and secure it with M3 6mm screws. That done, mount the remaining hardware and

complete the wiring as shown in Fig.4. The wiring to the the XLR connectors and switches is easier to install if they are not attached to the box but remember to pass the leads through the holes in the case before soldering to the terminals. The connectors and

The PC board is secured to the bottom of the case using machine screws, nuts and spacers. All external wiring to the board is terminated using PC stakes. Note the earth wire between the case and pin 1 and shield terminals of CON3



599

switches can then be mounted in place after wiring.

The LED is inserted into its hole in the side of the box by bending its leads over and pushing it into posi-tion. Make up a labelled paper or card panel (see heading photo) and glue it onto the lid and install the knobs to complete the final assembly.

TestingApply power using a 9V battery and

check that the battery test LED lights when the test switch is closed. Note that this LED will not operate if you are using a plugpack or phantom power. Test for 9V (when a fresh battery is powering the unit) or 12V when a plugpack is supplying power between pins 4 & 8 of IC1 & IC2.

Further testing can be done with a microphone and amplifier. Check the operation of the level control and the equaliser controls. The ground lift should only be used when there is a hum present in the signal. EPE

Fig.4: follow this wiring diagram to connect the external switches and sockets to the stakes on the PC board. Note that CON1 (balanced input) is a 3-pin female XLR socket, while CON3 (balanced output) is a 3-pin male XLR socket. The jack socket (CON2) provides the unbalanced signal output

Fig.5: this is the full-size (102 84mm) etching pattern for the PC board Reproduced by arrangement with

SILICON CHIP magazine 2006.www.siliconchip.com.au

ACCORDING to the song,Thunderbolt and lightning arevery, very frightening, althoughthis didnt worry visionary scientists likeFranklin and Tesla. Nowadays most peoplehave given up on the idea of stealing godsthunder but are exploiting lightning strikesfor highly practical research projects.

Most films begin with an establishingshot to put things in context, so Ill askyou to bring to mind the illustrations youprobably saw years ago of the Americanscientist Benjamin Franklin. For it was hewho in June 1752 performed a famousexperiment in which he successfully creat-ed electrical sparks from a key attached tothe conducting string of a kite that wasinsulated from ground by a silk ribbon.

O lucky manFranklin was a twice-fortunate man, lucky

once because he didnt kill himself in anexperiment we know to be highly dangerous(he was unaware). He was fortunate also inthat his name became inextricably associatedwith this stunt, since the same experimenthad been performed a month earlier inFrance at the behest of the naturalistThomas-Franois Dalibard. Franklin was, ofcourse, unaware of Dalibards work anddeveloped his researches to a greater degreeof perfection. The lightning conductor forprotecting structures was his idea alone.

Franklin set out and documented hisfindings in great detail, which is more thancan be said of the maverick genius NikolaTesla, born in Serbia but a US resident formost of his life. Teslas works, which arestill surrounded in mystery to some extent,took off in the 1880s after he was seized bythe notion of transmitting electrical poweron an industrial scale without using wires.His idea was to harness the immense powerof lightning and distribute artificially-madelightning to consumers through the air.

Doubtful sanityIts at this time that a saying of Robert

Frost comes to mind, namely that A civi-lized society is one which tolerates eccen-tricity to the point of doubtful sanity. In1899 Teslas laboratory created a high-fre-quency AC generator more than 16 metresin diameter that generated 300,000 watts ofpower and produced artificial lightningbolts 40 metres long.

So far, so good, but after this he aimed tosupply homes with what he called cosmicenergy, electrical forces from the Earthsupper atmosphere that could be collectedby spherical antennas on each roof. Hisexperiments along these lines ceased in1905, after which he transferred his atten-tion to creating a peace ray that would putan end to war by using macroscopic parti-cle beams that he termed teleforce.

Practical purposesHarvesting the heavens has not been

accomplished yet, although atmosphericelectricity has thwarted many other pro-jects. The wire antenna that the offshoreradio station Laser 558 tried in 1984 wasa case in point. The intention was for ahelium balloon to hold the antenna verti-cal but this failed continually as a resultof atmospheric electricity. Eventually thestation opted for a conventional T-anten-na slung between a pair of 100-footmasts.

According to The Weather Channel,we know far more about what doesntwork than what does when it comes toharnessing lightning. Their severe weath-er expert Dr Greg Forbes admits scien-tists have yet to determine what would bea practical method. It is tough to get asingle geographical spot that would behit often enough to really generate elec-tricity, he says, and each bolt is so shortin duration, youd need an awful lot ofthem to get a useful amount of energy.Its a neat experiment, but not realistic.

Scientists are still studying lightningnevertheless. American space agencyNASA believes that researching lightningwill give it a better idea of how the atmos-phere works as a whole. By characterizingthe electrical behaviour of storms, NASAmay advance the pursuit of more accurateforecasts, which has positive ramificationsfor emergency planning and preparedness.New Scientist magazine reported recentlythat scientists in the USA believe it may bepossible to predict the volume of waterstored in a storm cloud simply by recordingthe amount of lightning it produces.Studies involving satellites indicate that itsthe amount of ice inside a cloud that deter-mines the number of lightning bolts pro-duced. The next task is to correlate this fig-ure with the volume of rainfall likely to fol-low.

Unlucky strikeTheres an old saying that lightning

never strikes twice in the same spot. Werethis the case, insurers would pay out farless money in compensation but the truth isthat lightning strikes the easiest path toground whether it has been struck beforeor not. The Association of British Insurershas been looking at the frequency andseverity of lightning in relation to climatechange and has concluded that the overallnumber of lightning strikes per year willremain the same.

Reassuring as this may or may not be,there are many organisations that need toknow about the lightning of today broadcasters, railway operators and elec-tricity supply companies. This is why theEA Technology research centre at

Capenhurst, Cheshire, operates a dedi-cated lightning location system thatenables subscribers to see the locality oflightning anywhere across the UnitedKingdom and the north-western coast ofcontinental Europe on their PC screens.By logging particular trouble spots forlightning damage over a period of timeusers can refine the effectiveness of theirprotection systems, leading to betterinvestment policy decisions in future.

The mechanisms for providing thisinformation are elegant in the extreme,not just for the advanced technology usedbut also in the ingenious way that theprocess alerts users only to harmfullightning. It achieves the latter by locat-ing only cloud-to-ground strikes; its pri-mary purpose is assessing, locating andpredicting damage likely to haveoccurred. These cloud-to-ground strikesmake up a third of all lightning strikes(the remaining two thirds occur within orbetween clouds).Natural waveguide

Lightning strikes are detected by radiodirection finding techniques at the extralow frequency (ELF) of 1.1kHz, at whichfrequency the earths surface and the ionos-phere act together to create a naturalwaveguide that propagates ground wavesalone. Because there is no interfering skywave at these operating frequencies, thebearings produced are more accurate thanin conventional systems and the mainlyhorizontally polarised radiation from interand intra-cloud strikes is not registered atall, unless it is very close to a directionfinding station (within 30km).

At ground stations across the countrythe analogue signals from the directionfinding aerials are amplified, filtered andconverted into a bearing and strengthvalue. The data is then sent as a digitalsignal along permanent landlines toCapenhurst, where the strike is loggedand its position triangulated. With datafrom several base stations to compare,spurious signals caused by local interfer-ence can be rejected and genuine thun-derbolts triangulated anywhere in main-land Britain; often with an accuracy ofless than one kilometre.

Lightning fast!Each incident is plotted, and stored

along with its time and other data, on thecomputer mapping system. Subscriberscan watch the passage of an approachingstorm live on their PCs. Each new strikeappears on screen within seconds ofoccurrence. Indeed, it is possible to see aflash in the sky and watch the data arriveon the screen lightning fast, before hear-ing the clap of thunder!


Lucky Strike?Exploiting lightning for practical research

TTTT EEEECCCCHHHHNNNNOOOO----TTA L KA L K MARK NE LMARK NE LS O NS O N

Magnetic Cartridge Pre-ampKC-5433 11.75 + post & packingThis kit is used to amplify the 3-4mV signals from a phono cartridge to line level, so you canuse your turntable with the CD or tuner inputs onyour Hi-Fi amplifier - most modern amps don'tinclude a phono input any more. Dust off the oldLP collection or use it to record your LPs on toCD. The design is suitable for 12" LPs, and alsoallows for RIAA equalisation of all the really old78s. Please note that the input sensitivity of thisdesign means it's only suitable formoving-magnet, not moving-coilcartridges. Kit includes PCB withoverlay and all electroniccomponents. Requires 12VAC

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Theremin Synthesiser MKIIKC-5426 43.50 + post & packingBy moving your hand between the metalantennae, create unusual sound effects! TheTheremin MkII improves on its predecessor byallowing adjustments to the tonal quality byproviding a better waveform. With a multitude ofcontrols, this instrument's musical potential is onlylimited by the skill and imagination of its player.Kit includes stand, PCB with overlay, machinedcase with silkscreen printed lid, loudspeaker, pitchantennae, all specified electronic components and clear English instructions.

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IR Romote Control Extender MKIIKC-5432 7.25 + post & packingOperate your DVD player or digital decoderusing its remote control from another room. Itpicks up the signal from the remote control andsends it via a 2-wire cable to an infrared LEDlocated close to the device. This improvedmodel features fast data transfer, capable oftransmitting Foxtel digital remote control signalsusing the Pace 400 series decoder. Kit suppliedwith case, screenprinted fro

EPE 2007-01

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