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WIRING ALLOCATION TESTER
LOW-COST HOME ALARM
LOW-COST 10MHz COUNTER
PRECISION SERVO DRIVER
MAPLIN PROJECTS BOOK FORTY FIVE
EDITORIAL
I This Project Book replaces Issue 45 of Electronics, which
is now out of print, and contains a compilation of projects
from this magazine. Other issues of Electronics will also
be replaced by Project Books once they are out of print.
For current prices of kits please consult the latest Maplin
Catalogue or the free price change leaflet, order as CA99H.
I Editor Robert Ball1 Compiled by Mike Holmes.1 Contributing Authors Alan Williamson, Chris Barlow, Tony Bricknell.1Technical Authors Robin Hall, Mike Holmes.1Technical Illustrators Ross Nisbet, Kevin Kirwan, Paul Evans. Nicola HullI Production Scheduler Steve Drake.
Print Co-ordinators John Craddock, Len Carpenter.'Publications Manager Roy Smith'Development Manager Tony Bricknell1 Drawing Office Manager John Dudley"Art Director Peter Blackmore.'Designer Jim Bowler.1Published by Manila Electronics plc.Mail Order P 0 Box 3. Rayleigh, Essex SS6 8LR'Telephone Retail Sales: (01702) 5641611 Retail Enquiries: (01702) 552911 I Trade Sales: (01702) 554171.1 Cosine': (01702) 552941.i General: (01702) 554155.
Fax: (01702) 553935. I Telex: 995695
Visit a Maplin Shop for Personal Service.You'll lind Maplin Service inBelfast, 357-359 Lisburn Road. Telephone: (01232) 683929Birmingham, Sutton New Road, ErdingtonTelephone: (0121) 384 8411.Brighton, 65 London Road. Telephone' (01273) 620930.Bristol, 302 Gloucester Road, Horfield.Telephone. (01179) 232014.Cardiff, 29-31 City Road. Telephone (01222) 464554.Chatham, 2 Luton Road. Telephone: (01634) 818588Coventry, 12 Bishop Street Telephone (01203) 550504Dudley, Unit 7. Sterling Park Telephone: (01384) 485051Edinburgh, 126 Dairy Road Telephone: (0131) 313 5551Glasgow, 264-266 Great Western Road.Telephone. (0141) 353 3323.Ilford, 302-304 Green Lane. Telephone (0181) 599 0100.Leeds, Carpet World Building, 3 Regent Street.Telephone: (01132) 449200.Leicester, Office World Building. Burton Street.Telephone (01162) 623288.Liverpool, Edge Lane, Fairfield Telephone (0151) 230 0366.London, 146-148 Burnt Oak Broadway. Edgware.Telephone. (0181) 951 0969.107-113 Stanstead Road, Forest Hill. Telephone. (0181) 291 9192.120-122 King Street, Hammersmith Telephone: (0181) 748 0926.Manchester, 169 Cheetham Hill Road, Cheetham Hill.Telephone (0161) 832 25508 Oxford Road Telephone: (0161) 236 0281.Middlesbrough, Unit 1. The Forbes Building. 309-321 LinthorpeRoad Telephone (01642) 242900.Milton Keynes, Snowdon Drive (next to Office World), Winterhill.Telephone (01908) 692720Newcastle-upon-Tyne, Unit 4, Allison Court (beside The MetroCentre) Gateshead Telephone: (0191) 488 9555.Northampton, 139 St James Road. Telephone: (01604) 756726.Nottingham, 86-88 Lower Parliament Street.Telephone (01159) 410242.Portsmouth, 98-100 Kingston Road. Telephone: (01705) 654411.Preston, Unit 1, Corporation Street. Telephone: (01772) 258484.Reading, 129-131 Oxford Road. Telephone: (01734) 566638.Sheffield, 413 Langsett Road, HillsboroughTelephone (01142) 855492.Slough, 216-218 Farnham Road. Telephone: (01753) 551419.Southampton, 46-48 Bevois Valley RoadTelephone (01703) 225831.Southend-on-Sea, 282-284 London Road. Westcliff-on-Sea.Telephone (01702) 392000Stockport, 259-261 Wellington Road SouthTelephone (0161) 480 4900Stoke-on-Trent, 39-45 London Road Telephone (01782) 749947
All our shops are open from 9 00am to 5.30pm Monday 10 Saturday 19 30wri
Friday) Shops that are open on Sundays are. Brighton it local conditionspermit. Edinburgh 10 00am to 4 30pm. Glasgow 9 00am to 5.30pm. Manchester
Oxford Road and Cheetham Hill if local conditions permit Newcastle 10 00am to4 30prn. All shops are closed to Public Holidays Shops do not close for lunch
PROJECTS
WIRING ALLOCATION
TESTERI Traces wires in multi -way cables over
long distances.
10 ILIOneWxpenCsiOveSbTutHeffOecMtivEe homeALAalarm
that can connect to many different types
of sensor.
of
FOR MAIL-ORDER ENQUIRIES, PLEASE DO NOTCALL OUR SHOPS AS THEY WILL BE UNABLETO HELP YOU.Send all mail to: P.O. Box 3, Rayleigh, Essex SS6 8LR.
LOW-COST
I V 10MHz COUNTERI A frequency/period/unit counter with3 internal gate times, leading zeroblanking, reverse polarity protection
and 8 -digit LED display.
22ZN419/409 PRECISION
SERVO DRIVERI Specifically for use with pulse widthoperated servos, in a variety of controlapplications.
Copyright. All material is subject to worldwide copyright protection,and reproduction or imitation in whole or part is expressly forbidden.All reasonable care is taken to ensure accuracy in preparation of the
magazine. but Maplin Electronics plc cannot be held legally responsiblefor its contents. Where errors occur corrections will be published as soonas possible afterwards. Permission to reproduce printed circuit boardlayouts commercially, or marketing of kits, must be sought from thepublisher.
©Copyright 1994 Maplin Electronics plc.
1
Photo 1. Transmitter withtest leads.
Design by ELVText by
Alan Williamson
WIRINGCATION
TER
Features* Electronic Wire Identification* Independent Sender and Receiver* Up to 16 Wires Encoded Simultaneously* One Person Operation* Digital Readout of Wire Number* Crystal Controlled Accuracy
2
IntroductionThis project is a handy test instrument
which takes the hassle out of identifyingand trouble -shooting multi -way cableinstallations.
Anyone who has ever installed amulti -way cable between two locations inthe home or the office is probably familiarwith the problem of wire identification.Often the connections must be made inawkward, difficult -to -reach corners, whilecommunication with an assistant at the'other end' may be difficult or impossible(or you may have no assistant). Suchmulti -way cables are commonly used intelephone, intercom and alarm systems.
Obviously a cable of only 2conductors does not raise these sorts ofproblems, similarly if each conductor in amulti -way bundle has a unique colour. Inmany alarm systems, however, multi -waycables without colour coded conductorsare in common use for security reasons.Also difficulties with wiring allocation mayarise where a cable is extended by adding alength of multi -way cable that happens tobe available, but is not identical.
In these instances it would bereassuring to be able to check and recordthe function or number of each conductorin the cable. The Wiring Allocation Testerprovides this service in a fast and efficientmanner that eliminates the risk of wrongconnections. The system has two parts: atone end of the cable a code transmitter is
used to send a unique signal on eachconductor, while a special receiver at theother end checks whether each wire's codeis coming through with the aid of a digitalread-out. Both the transmitter and receiverare light -weight, battery -powered units inrugged ABS enclosures.
Principle of OperationThe transmitter can encode up to 16
different conductors at once by attachingsmall crocodile clips to the cable. If a cablehas fewer than 16 conductors, theremaining transmitter connectors aresimply not used. If there are more that 16conductors in the cable, then these can beallocated in groups of 16 at a time. It isimportant however to make sure that theconductors to which the transmitter isconnected have no voltages present orpower applied, nor should they be shortedtogether or cross connected at any point.
At the transmitter end, eachconductor must be labelled with numbers1 to 16, corresponding to the numbersprinted on the front panel of thetransmitter. The single lead at the oppositeside of the transmitter box is markedREFERENCE and must be connected, forany test, to the corresponding REFERENCElead on the receiver. In many cases it ispossible to make use of the cable screeningbraid if it has one, or a conductor in thebundle with some distinguishing featurethat makes it identifiable from the others. If
neither of these actions is possible then theREFERENCE leads on both the transmitterand the receiver may be clipped to anearby earth connection such as a metalwater supply pipe, or a central heatingpipe.
The receiver has two leads, one forground (REFERENCE) and one for testingany of the conductors previously allocatedat the other end of the cable. Both receiverleads have crocodile clips as used on thetransmitter. The signal input lead of thereceiver is connected to the requiredconductor in the cable. The instrumentindicates the number of the wire as definedat the transmitter side (1 to 16) on a liquidcrystal display (LCD). Short-circuits to theREFERENCE potential are indicated by thedisplay reading '36'.
Both the transmitter and the receiverare each powered by a 9V battery. Thebattery in the transmitter may be installedby unlocking the cross -head screw at theback of the instrument and removing thetop half of the enclosure. The receiver has aseparate battery compartment that may beopened without unlocking a screw.
The transmitter's battery will typicallylast for about 400 hours and the receiver'sbattery about 2,000 hours of operationassuming that a PP3 size Alkaline type isused (e.g. FK67X). The transmitter has ared flashing LED to indicate that the unit isswitched on, which goes out if the batteryvoltage drops below about 6.5V, thus
1 Ql= 32KHzR2
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Figure 1. Circuit diagram of the transmitter unit.
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Transmitter
indicating that a new one should beinstalled, but the instrument will continueto operate for a couple more hours.
The receiver's on/off slide switch islocated on the left-hand side panel of theinstrument. A conductor number isdisplayed when a valid code from thetransmitter is received.
The TransmitterThe circuit diagram of the transmitter
is given in Figure 1. The 9V supply voltageis applied to decoupling capacitor C3 viaswitch Si and R6. The voltage across C3 isused to power all transmitter circuits withthe exception of the LED. The actual circuitsupply voltage is of relatively littleimportance and lies between 5V and 8Vdepending on the number of conductorsconnected since CMOS ICs, as used here,can usually operate from supplies between3V and 15V
ICI is a 14 -stage, binary rippleup -counter containing an oscillatoroperating at 32.768kHz as determined bythe quartz crystal Ql. Divider stages in IC1provide a number of control signals for theother parts of the circuit. Output Q5supplies a frequency of 1024Hz, used toclock all of the four 4 -bit shift registers inIC2 and IC3 in parallel. The data input ofIC2a is tied to the positive supply line,resulting in a logic one being transferredfirst to Q1 and then to all outputs of IC2a oneach low to high transition of the clockpulse received from IC1.
As IC2a Q4 is the data source for thesecond shift register, IC2b, then Q1 of thesecond stage goes high on the fifth clockpulse applied to IC2a, and then outputsIC2b Q2, Q3 and Q4 go high on the sixth,seventh and eighth clock pulsesrespectively. This process continuesthrough IC3a and b until the last output togo high is Q4 of IC3b. In other words all 16outputs change state from low to high oneafter the other so that while the last,number 16, is high for just one clock cycle,the first is high fora full 16 clock cycles.
At the end of this Q10 of IC1 is used toclear or reset all shift registers to zero. Thereset state is of the same duration as theperiod in which all 16 clock pulses areproduted, so that when Q10 goes lowagain after 32 clock pulses, the shiftregisters are enabled again to accept theclock pulses supplied by Q5 of IC1. Thissequence is repeated, starting with thelow -to -high transition of Q1 of IC2a. The'on' (logic high) time of any shift registeroutput depends on its position in the chain,so that while IC2a Q1 has the maximumon -time of 16 clock periods, IC3b Q4 ishigh for only one period. It is by these timeperiods that the receiver recognises each ofthe 16 conductors. Hex inverters IC4 toIC6d buffer the 16 lines for output to thecrocodile clips as active low.
The power on indicator D4 has itsanode connected to the 9V supply voltagedirectly behind the contact of switch Si.The cathode is connected to the collectorof TI via 4.7V Zener diode D5, and thesetogether with associated components D6,D7 and R5 form a 10mA current source.The LED will light at constant brightness
IC1 QS
IC1 Q10
IC4 ST1
IC4 ST2
IC6 ST15
IC6 ST16
IC2 Q5
IC2 Q10
Display Load
ST3 Input
IC3d Reset
IC3a CountEnable
Receiver
IIIttttltttltttt1 2 3 4 5 6 7 8 9 10111213141516
Clock Cycles
Figure 3. Timing diagrams to illustrate the operation of the code transmitter and receiver.
while the battery voltage exceeds about6-7V. This value is obtained by subtractingthe sum of the voltage drops across R5(0.7V), D5 (4.7V), and D4 (1.3V) from thenominal battery voltage of 9V; there isnegligible voltage drop across thecollector -emitter junction of T1. If thebattery voltage drops below 6.7V, the LEDis rapidly reduced in brightness until it goesout at about 6-0V.
This current source is pulsed, therebyflashing the LED, to keep the overallcurrent consumption as low as possible.1C1 outputs Q12 -14 are combined with awired OR function provided by D1- 3 andR3 to produce an LED flash rate of about2Hz. This arrangement results in a powersaving of around 12-5%.
The ReceiverThe circuit diagram of the receiver is
given in Figure 2. Like the transmitter, thereceiver is powered by a 9V battery via Siand an RC network, R8 and C3. R8 has arelatively high value which ensures acircuit supply voltage of around 5V. Sincethe receiver circuit does not containcurrent -hungry components, the batterycapacity will be sufficient for about 2,000hours of operation.
Again a CD4060 oscillator/divider isused as the central clock source, IC2. The
clock pulse frequency at output Q5 is also1024Hz as derived from the quartz crystal,Q1, frequency of 32-768kHz. This signal isapplied to the clock input of a first decadecounter, IC4b at pin 9. The samplingperiod of the counter, duringwhich anumber of these clock pulses can becounted, is determined by the duration of a'gating' or enable signal applied to pin 10.This period 'gate' control originatesdirectly from the receiver's input.
The sequence of events can befollowed commencing with the momentwhen output Q10 of IC2 supplies a resetpulse. This low -to -high transition isdelayed by the integrator network R6 andC4 and inverted by IC3b which connects toIC3d. Because of the NAND logic functionof IC3d, this now inverted low level inputforces it to output a low -to -high transitionwhich is used to reset the counters in bothhalves of IC4, as well as the oscillator/divider, IC2. Consequently output IC2Q10 goes low again, terminating the resetpulse, and the circuit is then ready to begina new count cycle.
If the receiver's input at ST3 is opencircuit then the inputs of gate IC3a arepulled high by R5. As IC3a is wired as aninverter, its output is then at a constantlogic low level that maintains the first stagecounter IC4b in a disabled state by tying
5
IC5
S1 0 0 0 0 0 0 0 o 000000000 0 ° 0 00
o oC2 o o 0-0
0 C 3 IC2
00000000
IC4
01
ST17
D6 T 1001 POMO
000
II 4i 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
00000000
000
0 0 0 0 0 0 0 00---000-0 0
0 0 0 0 0 0 0 co
I
the enable pin low, even though thiscounter is receiving clock pulses. Thedisplay indicates '00' in this condition.
If however ST3 and ST4 areconnected, then IC3a outputs a logic highthat enables counter IC4b. Also on thistransition a monostable made up from C5,D4, R7 and IC3c generates a very short,logic 0 pulse for the other input of IC3d,which again will reset the two counters inIC4, as well as the oscillator/divider, IC2.Since the pulse is very short, these circuitsare re -enabled almost immediatelyafterwards, so that the clock pulsessupplied by output Q5 of IC2 may again becounted by IC4b and IC4a from thebeginning. It can be seen from this that,since the timebases of both the transmitterand receiver are identical, pulses from anyof the transmitter's outputs when applied toST3 will exactly synchronise bothtimebases.
DisplayThe four outputs of IC4b are in binary
format but only register '0' to '9' (BCD).After '9' the counter rolls over to '0' again,but a carry is effected by Q4 going lowwhile connected to the enable input ofIC4a. With the 'CLK' input permanentlygrounded, 'EN' of IC4a becomeseffectively a negative edge triggered clockinput to register a count of 10.
Because it need only discriminatebetween 0 and 1 (higher values than 16 donot occur), only Q1 of IC4a is connected tothe least -significant input of the associatedBCD to 7 -segment latch/decoder/LCDdriver IC5. The next higher input of IC5,
Photo 2. The finished receiver.
pin 3, is driven by IC3a, so that if ashort-circuit exists between a conductorand the reference (ground) potential, thisgate supplies a permanent logic high levelcausing the value received by IC5 to beincreased by '2'. As a result, the count of'1' from IC4a is changed into '3', and this is
MIST19 ("A ST16 ST14 ST12 ST10 ST8 ST6ST15 6143-0T11 ST9 06-T-7-1.5 ST4 ST3 ST2 ST1
ST18 +c3 0a0a013111111011111101111111.11100000000 00000000 00000000
OEIDO IC6
0001
Figure 4. Printed circuit board for the transmitter.
why short-circuits in the cable areindicated by the unique value '36' on thedisplay.
The low to high reset transition fromIC2 Q10 is also communicated via a
contrived from C6, D5 and R9 to the'STRB' inputs of both. IC5 and IC6, to latchthe count into the drivers for display. This iswhy there is a need to delay the reset pulsewith R6 and C4, so that the value can beretrieved before the counters are clearedby the same output, Q10. Since thepreviously established counter states arelatched in IC5 and IC6, the display readingdoes not change. When the input terminalsare disconnected, the display shows '00'after the next count cycle. Since themeasurement rate is about 30 per second,the display changes for each wireconnection test virtually immediately.
Since the LCD needs an AC backplanesignal, the Q8 output of IC2 is utilised forthis purpose, thus obviating the need foranother special backplane generator chip.The frequency of the backplane signal is128Hz.
Encoding the CableFigure 3 shows two timing diagrams
for the transmitter and receiver. It can beseen that while the output of IC4 ST1 of thetransmitter is low for all 16 clock cycles,each successive output goes low one cyclelater, until IC6 ST16 is the last to go low foronly one clock cycle. Hence each wire in acable loom is identified by the duration ofan active low pulse. Left to its own devices,i.e. with ST3 open circuit, the receiveridles at the same frequency but is notlocked to the transmitter, and the countersare reset to zero by the reset pulse from 1C2Q10 after every 32 clock cycles. Thedisplay shows '00' (open circuit or
6
'nothing') while IC3a output is low.When the receiver is connected to one
of the wires to test, the transmitted activelow pulse, if present, first synchronises thereceiver by the high to low leading edgeresetting both its timebase and displaycounters via IC3d, before enabling thecounters to count the timebase clockcycles with IC3a. The number of thesedepends on the length of the transmittedpulse and, because both the transmitterand receiver timebases are crystalcontrolled, the counts are very accurate. Ifthe test pulse is the longest (16 clockcycles) then the receiver will be able tocount a full sixteen of its own clock pulsesbefore 'reset' transfers the result to thedisplay. If however the test pulse is shorter,then the receiver is only allowed to count acorrespondingly fewer number of cycles.
Note that ST1 -ST16 do not Photo 3. Transmitter and receiver assembled PCBs.
correspond to the front panel numbers onthe transmitter, which are the reverse wayround. Hence ST1 outputs the longestpulse allowing the maximum of 16 counts(for wire 16), while ST16 has the shortestallowing only one count made by thereceiver (for wire 1). Hopefully this willavoid some confusion while testing theinstrument.
The input of IC3d is protected by R4 inseries with clamping diodes D2 and D3,the latter being a Zener type to limitpositive going inputs, as D2 alone wouldnot provide sufficient protection against
0 D2ST3 ST4 0000000
1C30 D6 C5x0 0 0 0 0 0 0 0-11--0
0r-0o
00000000000000000000 D40-0E0
D°1. R7 le
LCD1 ;10
TCs
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
?? 0 0 0 0 0 0 0 0 o o o o 0 o o o
1
IC5 IC6 D5
at00000000 000000000
0 -0
C3*
ST1 ST2
1*
0 00 0
co -NJ -00 0 0 00 0 0 00 0 cu oo o o o0 00 0 0 0
0
0-0
0
Figure 5. Printed circuit board for the receiver.
7
Crystal
serious input overload conditions,although it serves to prevent the inputs ofIC3a exceeding the chip's supply potential.
General PCB AssemblyFor those readers with little
experience in project building, a'Constructors' Guide' (stock code XH79L)is available to help with componentidentification. This helpful booklet alsocontains hints and tips on soldering andconstructional techniques. Please notethat, unlike most other Mapl in kits, thisguide is not included in this kit.
If errors are made during assembly ofthe PCB, the removal of a misplacedcomponent may be difficult withoutcausing too much damage, so pleasedouble-check each component type, valueand its polarity where appropriate, beforesoldering! Each printed circuit board (PCB)has a printed legend to assist in positioningeach item correctly, see Figures 4 and 5 forthe transmitter and receiver respectively,which also show the track layouts.
In each case install, solder and trimthe leads from all the components ensuringthan no wires stand proud of the board bymore than two or three millimetres.Commence with resistors and capacitorsfirst, and diodes last. Only after all othercomponents have been fitted would youthen carefully insert the relevant ICs intotheir places, making sure to correctly alignthe pin number 1 marker at one end of eachDIL package with the legend. All the ICs inthis design are CMOS types which can beat risk from static electric charge duringhandling, so do not remove them fromtheir protective packaging until they areneeded, and handle them carefully whenyou do so. All ICs have to be soldered inposition, which should be done carefullywith pauses of several seconds betweensoldering each pin. To ensure that thepackage lies flat on the PCB, solder twodiagonally opposite pins at two cornersfirst while pressing the device to the PCB.
Make sure that electrolytic capacitorsare fitted the correct way round. Thenegative lead, indicated by a dark stripeand minus (-) sign on the body of the
Section Thru PCB
Figure 6. Mounting the crystal Ql.
Figure 7. Mounting capacitor C3.
Figure 8. Positioning the transmitter power -onLED.
Figure 9. Mounting the receiver's on/off switch.
S1
0
0
ST3 ST4El
11111111111111111111111111111111
11111111111111111111Identification
Component Side
capacitor (or light stripe on a darkbackground), must be inserted in the holeopposite that marked as positive (+) on thePCB legend.
Transmitter ConstructionThe transmitter is built on a single
printed -circuit board. Construction is quitestraightforward with reference to thetransmitter parts list and the legend inFigure 4. Begin by fitting the wire links andresistors, then the capacitors. Fit the diodesand transistor next, but not the ICs just yet.Crystal Q1 should be mounted flat on thePCB as shown in Figure6, similarly soshould C3 as in Figure 7.
Push the terminals of the miniaturetoggle switch, SI , as far as possible into itsallocated holes, then solder them at thetrack side. Fit the LED D4 so that the lowerside of its plastic body is about 15mmabove the board surface, as shown inFigure 8. It may help to cut a 15mm widestrip of card for insertion between the pinsto accurately position this item.
Connect the battery clip wires tosolder points ST18 (+, red wire and ST19(-, black wire). ICs 1 to 6 can then beinstalled with regard to the precautionsmentioned earlier.
Seventeen crocodile clips and flexibleleads are provided with the kit for thetransmitter. The leads should be arrangedinto a regular colour distribution, witheither black or white for the individual'REFERENCE' connection. Insert the freeend of each lead into its respective hole inthe side of the top half of the transmittercase. Make a knot in each lead on theinside to provide a strain -relief and a freelength of about 1 Omm. Connect all 16signal input leads, and the single referencelead, to their respective points on the PCB,bearing in mind that, as mentioned earlier,wires numbered 1, 2 and so on go to ST16,15 etc., up to wire 16 at ST1, in 'reverseorder'. Otherwise the PCB will beconnected to the case top half back tofront! Finally attach the chosen'REFERENCE' wire to ST17.
Carefully fit the completed PCB intothe lower half of the enclosure, and install
Lid ofBox
1Bose-of Box
Figure 10. Orientation of the LCD.
8
5mm
Figure 11. Receiver box cut-out details.
and connect the battery. Remove the nutsfrom the switch's threaded boss and placethe top half of the enclosure onto the lowerhalf, while carefully drawing out al117leads up to their strain -relief knots. Alsomake sure that the top of the LED is aboutlevel with the front panel surface. Then thetop and the bottom halves of the case canbe secured with the self -tapping screwprovided.
Receiver ConstructionThe construction of the receiver is also
straightforward but a few special pointsshould be noted.
The LC display is not soldered directlyonto the board but instead plugs into thepair of 20 -way contact strips, which aresoldered in place first. These contact stripsraise the LC display a little so that its face isat the correct height for the front panel ofthe enclosure, but especially to preventheating of its pins by a soldering ironsplitting the glass! Do not insert the displayat this stage yet.
As with the transmitter, fit the wirelinks and resistors followed by thecapacitors and diodes. Again fit capacitorC3 and the crystal Q1 flat on the board. Tofit S1, cut off three 1 Omm long pieces of thewire supplied in the kit and solder these atone end into the three holes for the slideswitch Si . Make sure they remain vertical.Next, slide the solder terminals of Si overthe wires until S1 is flush on the board, andsolder in position, but without also meltingand moving the PCB solder joints on the
Photo 4. How the contact strips are used forthe LCD.
PCB! See Figure 9 for an illustration.Lastly install ICs 2 to 6 (there does not
seem to be an IC1 for some reason) with thesame care as for the transmitter. Carefullyinsert LCD1 into its.two rows of pinconnectors making sure it is the right wayround according to the alignmentidentification illustrated in Figure 10. The
result should be as shown in Photo 4. Withthis the PCB is practically complete. Thereceiver's pair of input leads are threadedthrough their holes and tied with a strainrelief knot in the same manner as those ofthe transmitter. The red wire goes to ST3,the black (or white) to ST4. The battery clipred wire goes to ST1 (+), and the blackwire to ST2 (-).
Turn the receiver's case front or tophalf front -side down, and install the PCB init with the LC display facing down behindthe window aperture. Push the PCB downuntil the surface of the LCD is about levelwith the inner front panel surface. Don'tforget that these LCDs often have a thin,protective plastic film on the front glasssurface which should be peeled off. ThePCB is secured with two self -tappingscrews at the side of the batterycompartment. Apply glue beside the inputterminals to secure the PCB in this area.
Remove the battery cover andassemble the two halves of the case. At thesame time, as with the transmitter, drawout the two input wires and guide thebattery clip wires to the batterycompartment, through the slot provided. Ifnecessary adjust the position of the batteryclip in the compartment.
Join the two case halves with thescrews provided, and install the battery.The wiring allocation tester is now readyfor use. No alignment is required, butproper operation can be verified bydirectly examining each of the transmitter'soutputs in turn with the receiver.
RECEIVER PARTS LISTRESISTORS
TRANSMITTER PARTS LISTRESISTORS:
R1 20M 1 R1 20M 1
R2 33k 1 R2 33k 1
R4 10k 1 R3 100k 1
R5,R8 100k 2 R4, R6 10k 2
R6, R7 22k 2 R5 6811 1
R9 82k 1
CAPACITORSCAPACITORS Cl ,C2 33pF 2
Cl ,C2 33pF 2 C3 100µF 16VC3 1µF 16V 1
C4,C5 lOnF 2 SEMICONDUCTORSC6 1 nF 1 IC1 C4060BE 1
IC2,1C3 C4015BE 2
SEMICONDUCTORS IC4-6 C4049UBE 3
IC2 C4060BE 1 T1 BC548 1
1C3 C4011BE 1 D5 ZPD 4V7 Zener 1
IC4 C4518BE 1 D1-3,D6,D7 1N4148 5
IC5,1C6 C4056BE 1 D4 3mm LED Red 1
D3 ZPD 8V2 Zener 1
D1 -D5 1N4148 5 MISCELLANEOUSQ1 32.768kHz Miniature
MISCELLANEOUS Quartz Crystal 1
Q1 32.758kHz Miniature S1 SPDT Min Toggle 1
Quartz Crystal 1 PP3 Battery Clip 1
LCD1 31/2 Digit Display 1 Test Lead with Crocodile Clip 17S1 SPDT Slide Switch 1 Silvered Wire 39cm
PP3 Battery Clip 1 Instruction leaflet 1
40 -Way IC Contacts 1 StpTest Lead with Crocodile Clip 2
Silvered Wire 39cmThe above items are available as a kit only:
Order As LP61R (Wire Alloc Tester Kit).
9
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FEATURES* Low Cost* Normally Open and
Closed Security Loops* Arm Key Switch
* AdjustableExit/Entry Delay
* Tamper and PanicButton Loops
* Audio/VisualStatus Indicators
* Extremely LowStandby Current
/10
tmaatmaatritmaatiatiaanSpecifications of PrototypePower supply input voltage:Current at 12V:
Siren Switching Current:Exit/Entry Delay Time:Security Loops:Tamper Loop:Panic Button Loop:
Photo 1. Completed PCB.
Introduction
6V to 12VDCStandby = 1 3µAActive = 3mAIntruder= 7.5mAHelp = 4.5mA1 A Maximum1 to 60 secondsNormally Open and Normally ClosedNormally ClosedNormally Open
The need for an inexpensive buteffective home alarm is becoming ofgreater importance as time passes. Thissimple unit has several features which arenormally found on more expensive alarmsnow available.
No alarm can offer completeprotection against the determinedprofessional burglar, but it will act as astrong deterrent to the small-time thief.This alarm can be triggered from a widerange of security sensors, such as a reedswitch, pressure mat, window foil, etc.It can be expanded further to include heat,vibration and infra -red detectors. Thissystem flexibility ensures that the potentialthief never knows just what to expect fromhouse to house.
The operating principle is that whenthe arm key is turned on, you then have upto 60 seconds to secure the building;during this exit time a buzzer will besounding. After this delay the alarm isactive and ready to be triggered by any ofthe sensors in the security loops. If you arestill inside the building a red indicator actsas a reminder that the system is active.
When one or more of the sensors isdisturbed the alarm is triggered, lightingthe intruder indicator and sounding thebuzzer. You now have up to 60 seconds ofentry delay to deactivate the alarm beforethe main siren goes off.
The alarm is equipped with twoadditional security loops which arepermanently active and immediatelytrigger the main siren when disturbed. Thefirst of these is a 'tamper -proof' loop whichwhen broken sounds the siren until it isre -connected. The second loop is used formanually operated panic buttons, and ifeither loop is triggered, the help indicatorwill light up until the alarm is reset by thekey switch being turned from the standbyto the armed condition.
Circuit DescriptionA circuit diagram detailing the
complete unit is shown in Figure 1. Thetiming and control of the sequence ofevents is governed by the logical functionof the following Integrated Circuits (IC) andTransistors (TR):
IC1 TLC555 timer, 1 to 60 secondsexit/entry delay.
IC2a,b 4001BE latch, alarm active andexit/entry delay select.IC2c,d 4001BE latch, security loop trigger.IC3a,b 4011BE gate, siren entry delay.
IC3c,d 4011BE latch, tamper and panicloop trigger.TR1 BC548 timer entry re -trigger.
TR2 BC548 exit/entry buzzer switch.TR3 TIP122 siren switch.
PCB ConstructionAll information required about
soldering and assembly techniques can befound in the 'constructors guide' includedin the kit (stock code XH79L). Removal of amisplaced component will be fairlydifficult so please double-check eachcomponent type, value, and its polaritywhere appropriate, before soldering! ThePrinted Circuit Board (PCB) has a legend tohelp you correctly position each item, seeFigure 2. Install all the componentsincluding the buzzer which is secured tothe board using the 8BA screws and nuts.When mounting the red Light EmittingDiodes (LEDs) you must ensure that theirpolarity and positioning is correct. Thecathode (K) is denoted by the shorter of thetwo leads and by a flat on the bottom edgeof the package as shown in Figure 3.
When the assembly of the circuitboard is complete you should check yourwork very carefully, making sure that allsolder joints are sound. It is also veryimportant that the solder (track) side of thePCB does not have any trimmedcomponent leads standing proud by morethan 2mm, as they may cause shortcircuits. The completed PCB assembly isshown in Photo 1.
TestingAl) the tests can be made with the
minimum of equipment. You will need aregulated 12V DC power supply, or 12Vbattery, capable of providing the currentrequired by the siren you have chosen touse, but which must not draw more than1A, and some hook-up wire. The followingquoted meter readings were taken from theprototype using a digital multimeter; someof the readings you obtain may vary slightlydepending upon the type of meter you use.
Before you commence testing theunit, set the two presets, RV1 and RV2,fully counter -clockwise (CCW). Next, fittwo wire links to Terminal Block 3 (TB3) asfollows:
Terminal 3 to 4 (normally closed securityloop), see Figure 4.
Terminal 7 to 8 (normally closed tamperloop).
Prepare the key switch S1 and siren SRI ,then connect them to TB2 as follows:
S1 to terminals 1 and 2 (set key switch to itsclockwise ON position).SR1 red lead (+V) to terminal 3 and black(-V)to 4.
Do not connect any power to TB1 until it iscalled for during the testing procedure!
11
TR
18C
548
100k I
CI
R2
1004
C12
2u2F
2
R4
4k7
LO1
AC
TIV
E
C2
NM
100n
F
ICI
TLC
555
3
R3
722
k
R5
4k7
+11
1111
C3
C4T
1=1
100n
F22
uF
T
TR
2
B21
R6
C5
R9
100k
100n
F4k
7
INT
RU
DE
R
4001
8EIC
2 c
LD2
4001
8E
EN
TR
Y
CC
W
BC
548
DI
1N41
48
A05
I N41
48
CC
W
EX
IT
It '1
22M
213
3
I C2
o
3
1N41
48
RV
I02
2M2
IC2b
4001
8E5
1N41
48
R7
100k
4
R15
1
TB
3
4k7
R8
TB
352 N /
0
SE
CU
RIT
YLO
OP
10
IC2d
4001
8E12 13
10M
CS
MN
10nF
R16
TE
13
100k
3 4
53T
B3
N /
C
SE
CU
RIT
YLO
OP
I 00n
F
I C3
4011
tlE
R12 4k 7
11
C7
100n
F
HE
LP LD3
V40IC
31g
1IB
E
6 13
TB
3
TA
MP
ER
LOO
PT
133
RII
4k 7
TB
2
SIR
EN
-+
-C>
3
SR
I
041N
4148
IC3
g40
11B
E
C9
NM
R18
100n
F
747
0kR
1947
0k
RIO
12
4011
8E
11)1
006
1N41
48
100k
54P
AN
ICB
UT
TO
N
T83
CE
1
TB
3lO
nF 1
.15
6
R17
1014
R13
100k
TB
2
R14 4k 7
07IN
4148
TR
3T
IP12
2
C10
100n
FC
I1
T22
0uF
2
182
51 AR
MT
B2
TB
I
OV
Figure 2. PCB legend.
The first test is to ensure that there areno short circuits before you connect thepower supply. Set your multimeter to readOHMS (f1) on its 20kf1 or equivalentresistance range, and connect the testprobes to terminals 1 and 2 of TB1. Withthe probes either way round a readinggreater than 1 kil should be obtained.
Before testing the currentconsumption of the unit, set S1 to itscounter -clockwise OFF position. It is alsorecommended that the output of the siren ismuffled to reduce its sound intensity! Now
set your meter to read DC mA and place itin series with the positive line of the powersupply to TB1 terminal 1. When thenegative power line is connected to TB 1terminal 2 the following should beobserved:
1. None of the LED's should light.2. Buzzer should not sound.3. Siren should not sound.4. A current reading of approximately
13p,A should be obtained.
Next, turn the key switch clockwise toits ON position, which should arm thealarm system. At the same time the buzzershould sound for approximately onesecond, and at the end of this time theactive indicator, LD1, should light. Repeatthis procedure whilst advancing theposition of RVI in small steps. Each time
the setting is increased, the exit delayshould also increase until, when RV1 isfully clockwise, a maximum delay ofapproximately 60 seconds is reached.During the exit delay a current reading ofapproximately 35mA should be observed,dropping down to 3mA when the system isactive.
To test the alarm trigger function, eachsecurity loop on TB3 must be individuallyopened or closed. Set RVI and RV2 fullycounter -clockwise. Then turn the keyswitch S1 to its ON position (system armed)and perform the following tests:
la. Link terminals 1 and 2 (normally opensecurity loop).
Result: Active indicator LD1 goes out.Intruder indicator LD2 lights up.Buzzer sounds for a one second entrydelay.
TB3
ecaseeeee'1Normally
open
SecurityloopS2
Normallyclosed
SecurityloopS3
Tamperloop
0Panicbutton
S4
TB2 TB1
ecsee
SirenSR1
e®
+ -+12VPowerinput
Figure 3. LED information. Figure 4. Wiring diagram.
13
1
Photo 2. Batteries and AC adaptor (FK64U,RK44X, YJ19V, YJ22Y, YB23A). Photo 3. Sirens (11(42V, 11(43W, YK60Q, YP11M, XG14Q, YN59P, YZO3D).
A
TB1
0®
+12V I
Battery
T_
B
TB1
0®
+12V300mA
Regulatedmains
adaptor
+12VBattery
1N4001
1N4001
C
TB1
0®
A
+12V300mA
Regulatedmains
adaptor
Figure 5. Power supplies.
Active indicator LD1 lights up.Siren SR1 sounds.Supply current reading increases bythat demanded by your siren.
1 b. Reset the alarm by turning the keyswitch off (system standby).
Result: All indicators go out.Siren stops sounding.Current reading drops back to 1 .3µA.Remove the link from terminals 1 and 2.
2a. Re -arm the system.Remove the link from terminals 3 and 4(normally closed security loop).
Result: Same as test 1 a.
2b. Reset the alarm (system standby).
Result: Same as test 1 b.Refit the link at terminals 3 and 4.
3a. Link terminals 5 and 6 (normally openpanic loop).
Result: Help/tamper indicator LD3 lights up.Siren sounds immediately.
3b. Remove the link from terminals 5 and 6.Arm the system.
ResUlt: Help/tamper indicator LD3 goesout.Siren stops sounding.Reset the alarm (system standby).
4a. Remove the link from terminals 7 and 8(normally closed tamper loop).
Result: Same as test 3a.
4b. Refit the link at terminals 7 and 8.Arm the system.
Result: Same as test 3b.Reset the alarm (system standby).
This completes the testing of the alarm.Now disconnect the power, test links andyour multimeter from the unit.
Using the AlarmBefore the completed module can be
used in a practical working environmentthe following operating conditions shouldbe considered.
Power Supply: as can be seen from Figure5, there are three basic power supplyoptions. The simplest is shown in 'A' wherea 12V battery supplies all the power to the
alarm system. It must be remembered thatthe capacity of the battery will determinethe effective operational life of the unit,which is in turn governed by the sequenceof events. In its standby condition thealarm draws very little current (1.3µA), soeven small capacity batteries will last for arelatively long period. However, whenarmed the supply current increases to 3mAand once triggered the current drawn bythe siren can go up to lA depending uponthe type you have selected. For this reasonit is advantageous to use a battery with ahigh capacity to ensure good long termoperation, as illustrated in Photo 2.
The second option, 'B', uses a 12Vregulated mains adaptor which must havesufficient current capacity to drive thesiren. The prototype used a siren whichdrew less than 300mA, so only a smallmains adaptor (YB23A) was necessary.Although this option gives a virtuallyun-interrupted supply you must take intoaccount the fact that should the 240V ACmains fail, then the alarm system is leftinoperable. For this reason a secondarybattery back-up supply is advantageous,as indicated in option 'C' of Figure 5.Combining both supplies requires two1 N4001 1 A rectifier diodes (QL73Q)connected as shown which effectivelyisolate the supplies from each other.
Siren: as can be seen from Photo 3 thereis a wide range of sirens available fromMapl in, and their current consumptionstarts as low as 30mA (YP1 1 M), extendingup to 600mA (YN59P). Since the alarm hasa switching capacity of 1 A it is permissibleto use more than one siren as long as thetotal current demand is less than 1 A andwithin the capacity of the power supply,in other words the following combinationsare possible:
Where all sirens are wired in parallel:Up to 33 30mA piezo electronic sirens(YP11M), total current 990mA.Up to 6 150mA micro sirens (JK42V), totalcurrent 900mA.
14
Up to 3 300mA miniature piezo sirens(JK43W), total current 900mA.Up to 3 300mA low cost electronic sirens(YK60Q), total current 900mA.Up to 3 300mA staccato electronicsounders (YZO3D), total current 900mA.Up to 2 500mA electronic sirens (XG14Q),total current 1A.1 600mA metal horn siren (YN59P).Or any combination of these totalling 1A.
The siren chosen for testing the prototypewas the micro siren (JK42V) drawing only150mA but producing a very loud output.All the sirens are loud and there must becareful consideration when choosingwhere to install them as you could veryeasily upset the neighbours!
Box: it's good practice to build as much aspossible into the box, because the morewiring there is outside the easier it is totamper with. The choice of box willdepend upon the following design criteria:
1. Size of assembled alarm PCB.
2. Size of batteries.
3. Size of mains power supply. Can beexternal if battery back-up fitted.4. Size of siren. Additional sirens can beoutside the box.5. Box material plastic or metal.6. Free-standing or wall mounted.
7. Front panel layout and markings.
A comprehensive range of boxes isavailable from Maplin which can be foundin the current catalogue.
Security Sensors: as can be seen from
Photo 4. Security loop sensors (YW46A, FK77J, lU65V, YW47B, FK46A, FP12N, YZ67X, YB91Y, FK79L,YW50E, YW51F, FP11M, YU81C, jG24B, YM87U, FK47B, FK78K, YW48C, YW49D, FK76H, PA77J).
Photo 4 shows a wide range of sensors andyour selection will depend on yourrequirements. Here is a list to help youselect those most suitable for your needs.Reed switchesRecessed door or window YW46ARecessed five terminal door orwindow FK77J
Recessed panel pin fixing,five terminal door or window JU 65VSurface mounting, door orwindow YW47B
Panic buttonsRound panic buttonHelp buttonMetal panic button
Pressure matsStandard carpetStair carpet
FK46AFP12NYZ67X
YB91YFK79L
Window protectionWindow foilFoil terminalsGlass break detector
Infra -redPhoto relay systemIndoor pulsed infra -redmovement detectorIndoor passive infra -redmovement detector
MiscellaneousHeat detectorVibration detectorDoor junction box5 -Way junction box8 -Way junction box4 -Core burglar
alarm cable (1 metre(100 metres)
YW50EYW51FFP11M
YU81C
JG 24 B
YM87U
FK47BFK78KYW48CYW49DFK76H
XR89WPA77J
LOW COST HOME ALARMPARTS LISTRESISTORS: All 0.6W 1% Metal Film
Bolt 8BA 1/2in. 2 BoltsNut 8BA 2 NutsConstructors' Guide 1
(BFO9K)(BF19V)(XH79L)
R1,2,6,7,10,13,16 100k 7 (M100K) Home Alarm Leaflet 1 (XTO3D)
R3 22k 1 (M22K)R4,5,9,11,12,14,15 4k7 7 (M4K7) OPTIONAL
R8,17 10M 2 (M10M) SR1 Micro Piezo Siren 1 (JK42V)
R18,19 470k 2 (M470K) S4 Help Button As Reqd (FP12N)
RV1,2 Hor Encl Preset 2M2 2 (UHIOL)Security Loop Switches:
CAPACITORS 52 Std Pressure Mat As Reqd (YB91Y)
C1,2,3,5,7,9,10 Disc Ceramic 100nF 7 (YR75S) S3 Surface BA Reed As Reqd (YW47B)
C4 PC Electrolytic 22µF 25V 1 (FF06G) Window Foil As Reqd (YW50E)
C6,8 Disc Ceramic lOnF 2 (BX00A) Foil Terms As Reqd (YWS1F)
C11 PC Electrolytic 220µF 16V 1 (FF13P) 4 -Wire Burglar Cable As Reqd (XR89W)
C12 PC Electrolytic 2µ2F 100V 1 (FFO2C)Batteries:
SEMICONDUCTORS Alkaline KAA 8 (FK64U)
D1,2,3,4,5,6,7 1N4148 7 (QL80B) 12V Battery Box 1 (RK44K)
LD1,2,3 LED Red 5mm 2mA 3 (UK48C) PP3 Clip 1 (HF28F)
TR1,2 BC548 2 IQB73Q) Gen Purpose 991 2 (Y)19V)
TR3 TIP122 1 (WQ73Q) Gen Purpose HP992 2 (Y123A)
IC1 TLC555CP 1 (RA76H) Gen Purpose HP1 1 (YJ22Y)
1C2 4001BE 1 (QX01B) AC Adaptor Regulated 1 (YB23A)
IC3 4011BE 1 (QX05F) Rectifier Diode 1 N4001 2 (QL73Q)
MISCELLANEOUS
TB ITB2TB351
DIL Socket 8 -PinDIL Socket 14 -PinLow Cost Alarm PCB2 -Way PC Terminal4 -Way PC Terminal8 -Way PC TerminalPlas Key Switch
1
2
1
1
1
1
1
(BL17T)(BL18U)(GE82D)(FT38R)
(RK73Q)(RK38R)(FV42V)
The above parts, not including Optional items,are available as a kit:
Order As LP72P (Low Cost Home Alarm Kit)The following item is also available separately
although not shown in the 1991 Maplin catalogue:Low Cost Alarm PCB Order As GE82D
BZ1 Buzzer 12V. 1 (FL40T)
15
by Tony Bricknell
LOW COST7n u
1111Y TERsuiFEA T U R E S
* Functions as a frequency counter/period counter/unit counter* Three internal gate times in frequency counter mode* 10 cycle, 100 cycle and 1000 cycle gate times in period mode* Leading zero blanking and automatic decimal point shifting* Reverse polarity protection * Reset switch for added flexibility* 8 Segment multiplexed LED display * Low cost design* Minimal wiring required
16
11111111111111110C>his project is the first in a
0suite of low cost testequipment for the hobbyist.
During this series the constructionof several useful items of testequipment will be covered.
1 . 2 . 3 . 4 . 5 .
There are many multifunction countersavailable but, unfortunately, most arepriced way out of the range of the homehobbyist. This project aims to fill the gap inthe lower end of the market by offering acounter, packed with features normallyfound on its more expensive counterparts(no pun intended).
The design is based on the IntersilICM7216A, giving measurements offrequency, periodic time or totalisingcounter (event counter). The counter inputhas a maximum frequency of 10MHz infrequency and unit counter modes, and2MHz in periodic time mode. For periodmeasurement the unit gives a 0.1msresolution. In the frequency mode, the usercan select input gating periods of 01, 1 or10 seconds. With a 10 second gate time, thefrequency can be displayed to an accuracyof 0.1Hz in the least significant digit. Thereis a delay of 0.2 seconds between eachmeasurement for all ranges, and theICM7216A allows leading zero blanking andautomatic decimal point positioning,according to range to be incorporated. Thereading is displayed in kilohertz in thefrequency mode, and in micro -seconds forthe time measurement mode. Four 0.56in.high contrast, double digit displays areused, which are multiplexed at 500Hz with a12.5% duty cycle for each digit. A fullspecification of the prototype can be foundin Table 1.
Input AmplifierWith reference to Figure 1, it can be
seen that the signal input on PI (signal) andP2 (ground) is immediately capacitivelycoupled to remove any DC bias. The signal,clamped by Dl and D2, enters a wide banddiscrete amplifier. To achieve a high inputimpedance an FET is used for TR1. Theoutput signal from the drain of TR1 is fedinto TR2, to provide a clean switchingwaveform to drive the A input of IC1.
Logic and DisplayIC1 handles the range and function
switching, display buffering andmultiplexing, and the internal and externaloscillators. Its block diagram can be found inFigure 2. The output from the collector ofTR2 enters ICI on pin 28. The internalcrystal frequency is determined by thesetting of VC I. IC1 provides the digit andsegment drive for the 8 -digit, 7 -segmentdisplay. The function and range inputs aretime multiplexed to select the input functiondesired. This is achieved by connecting theappropriate digit driver output to the inputs.Noise on the multiplex inputs can causeimproper operation, which is particularly Figure 1. Circuit diagram.
17
EXTOSC 0Input
OSCInput "-
OSCOutput o
ResetInput 0
OSC
SELECT
+104 or +10
103
RANGE
SELECTLOGIC
DECODERDIGIT
DRIVERS
Digit-0 Outputs
(8)
InputA 0
Input 0B
STORE ANDRESET LOGIC
RANGE
CONTROLLOGIC
FunctionInput 0
Hold0Input
CONTROLLOGIC
CONTROLLOGIC
FN
CONTROLLOGIC
EN
+1 011COUNTER
CL OVERFLOW
DATA LATCHES& OUTPUT MUX
STORE
D.P.LOGIC
QD
CL
R
MAINFF
DECODER
LOGIC
CONTROL
LOGIC
SEGMENT
DRIVER
Range0 Input
Control0 Input
7 Segment-o do D.P.
Outputs
Figure 2. Block diagram of the ICM7216A.
Supply voltage 10V -15V
Average supply current 0 12V 110mA
Nominal input impedance 1M 11
Input signal frequency range 10Hz-10MHz
Input signal amplitude (p.d.)10kHz - 1MHz input frequency, 30mV1MHz - 5MHz input frequency, 45mV5MHz - 10MHz input frequency, 90mV
Functions Frequency, Periodic time, Unit counterGate times 0.1, 1, 10 seconds (Frequency mode)
10, 100, 1000 cycles (Period mode)Best resolution 0.1Hz (Frequency mode)
0.1us (Period mode)Indicators 8 seven-segment displays, 2 range LED's,
Over-range
Timebase 10MHz high-stability crystal
Table 1. Specification of prototype.
true when the unit counter mode isselected, since voltage changes on the digitdrivers can be capacitively coupled throughthe LEDs to the multiplex inputs. Formaximum noise immunity, a low pass filterconsisting of a 10kf2 resistor and 68pFcapacitor is placed in series with themultiplexed inputs.
Power SupplyA 12V regulated input is required
which can be supplied from an AC adapter.D3 ensures that no damage will be done tothe circuit if the power supply is connectedwith incorrect polarity. This 12V linepowers the front-end amplifier directly,while a regulated 5V line is taken from thissupply to drive all the additional circuitryincluding the LED display.
ConstructionThe Low -Cost Counter is constructed
on a single -sided glass fibre PCB, chosenfor maximum reliability and stability.
Figure 3 shows the PCB, with printedlegend, to help you correctly locate each
18
11111111111111111item. The order in which the componentsare fitted is not critical, however thefollowing instructions will make theassembly task as straightforward aspossible. For general information onsoldering and assembly techniques, referto the Constructors' Guide in the kit.
From the short length of 22 s. w. g. TCwire included in the kit, cut and fit the 39links. Next, fit the four PCB pins. Afterinsertion, use a hot soldering iron to pressthe pins into position. If sufficient heat isused, it should not be necessary to use agreat amount of force. Once in place, thepins may be soldered.
Now fit the remaining components,starting with the small resistors and diodes,working upwards in size until the switchesare fitted last. The IC socket should befitted before any other high profilecomponents, as it must be kept flush withthe PCB. Ensure that the notch at the endof the socket aligns with the white block onthe legend. Do not insert the IC until it iscalled for during the test procedure!
Special precautions are needed whenfitting the semiconductors (diodes andtransistors). In particular, take care not tooverheat them during soldering. All thesilicon diodes have a band identifying oneend, be sure to position these adjacent tothe white blocks marked on the legend.
Figure 4. Inserting LD1, LD2 and DYI-4.
When installing the transistors, match theshape of each case to its outline on thelegend. Take care with the polarity of theelectrolytic capacitors, which is indicated bya full-length negative (-) stripe, the leadnearest this symbol goes into the holeopposite to that marked with a positive (+)symbol on the legend.
Install LD1 and LD2 at a height of 5mmabove the PCB, matching the flat side of thepackage with that shown on the legend. Thedouble-digit displays DY1 -4 are installednext, and must be raised off the PCB to aheight of 4mm, as shown in Figure 4.
Before continuing further it isrecommended that you take severalminutes to double-check your work to makesure that there are no dry joints, or straystrands of solder that could cause a shortcircuit. It is also very important that thesolder side of the circuit board does nothave any trimmed component leadsstanding proud by more than 3mm, as thismay cause a short circuit.
No specific box has been designatedfor the project, however, the single boardprototype fitted nicely into an ABS box with Figure 3. PCB with legend.
19
1111111111111111127 rii
metal front panel type M4005 (stock codeWYO2C), see Figure 5 for box drillingdetails.
The choice of connectors for thepower and input leads is entirely up to you.However, it is good practice not to use thesame type of connector for differentfunctions.
When installing the complete PCBassembly remember to use some form ofspacer between its solder side and theinside surface of the case, particularly vitalif you are using a metal case or chassis.
Setting Up and TestingApply power to the PCB (+12V to P3,
OV to P4) and check the voltage presentacross pin 18 (+V) and pin 8 (OV) of thesocket for ICI using a multimeter. A
toO
1020
CN
NO
0
0
Hole dataA. 03mmB. 03.5mm CSKC. 05mmDimensions in mm
21
25
136
Figure 5. Box drilling details.
kHz #Ps 0
Freq.
0.13
kHz
ps 0n
Un
Un
Figure 6. Display conditions.
reading no greater than 5.5V and no lessthan 4.5V should be present. If there iszero volts present then you may have thepower supply polarity incorrectlyconnected. By moving S2, LD1 and LD2may be made to illuminate. If everything issatisfactory, remove the power supply andinsert IC2. Be careful not to bend the pinswhich are easily damaged. Temporarilyshort together P1 and P2, and re -connectpower. The format of the display will differdepending which mode you are in. Switchthrough the ranges with S2 and check thatthe display varies as shown in Figure 6. Themultifunction counter is now fully working.
kHz
Period
.0 LInn
kHz 0
Period
X100-MI
kHz 0PS 3#E
kHz 0Ps 0
Unitcounter
Not used inunit counter
mode
nnnl.0 1- t
n rt n.LIUUIJ
Lwi
The completed PCB. A project you can count on!
33
1111111111111111Calibration andAccuracy
The unit is calibrated by applying asignal of known frequency and accuracy tothe input, and then adjusting VC1 until thecorrect frequency is displayed. The settingof VC1 will determine the accuracy of theunit, and care should be taken in making thisadjustment. However, if a reference signalis not available, set VC1 to its mid -point. Itwas found that, on the prototype, thisprocedure produced a small, but acceptableerror equating to 0.002%, with an inputfrequency of 10MHz.
In a universal counter such as this, itmust be realised that there can be crystaldrift and quantisation errors. In frequencyand period modes, a signal derived from theoscillator is used by either the referencecounter or the main counter. Therefore, inthese modes an error in the oscillatorfrequency will cause an identical error in themeasurement. For instance, an oscillatortemperature coefficient of 2OppinPC willcause a measurement error of 2OppmPC.
Mode Main Counter Reference Counter
FrequencyPeriodUnit counter
Input AOscillatorInput A
1 00Hz (Oscillator - 105)Input ANot Applicable
Table 2. Internal counters.
In addition, there is a quantisationerror inherent in any digital measurement of±1 count. Clearly this error is reduced bydisplaying more digits. In the frequencymode the maximum accuracy is obtainedwith high frequency inputs, and in periodmode maximum accuracy is obtained withlow frequency inputs.
In UseThe selected mode of operation
decides which signal is counted into the maincounter, and which signal is counted by thereference counter, as shown in Table 2.
Reset switch Si - When the resetswitch is depressed, any measurement inprogress is stopped, the main counter isreset, and the chip is held ready to initiate anew measurement. The latches which hold
the main counter data remain enabled,resulting in an output of all zeros. When theReset switch is released, a newmeasurement is initiated.
Function switch S2 - Changing thefunction with S2 will stop the measurementin progress without updating the display,and then initiate a new measurement. Thisprevents an erroneous first reading afterthe function switch is moved.
Gate switch S3 - In frequency countermode this switch selects a 0.1s, is or lOsgate time. In period mode the switchselects 10 cycle, 100 cycle or 1000 cyclegate times.
In every range, any overflow is shownby the decimal point in the most significant(left-hand) digit being illuminated.
LOW COST 10MHz COUNTERPARTS LISTRESISTORS: All 0.6W 1% Metal FilmR1,12 22011R2R3R4, 5R6R7R8, 9R10,11
CAPACITORSClC2C3C4,6,12C5C7C8,9C10C11VC1
1M4k71k47k4701210M10k
220nF Poly Layer220pF Ceramic100pF Ceramic100nF 16V Minidisc Ceramic220p.F 16V PC Electrolytic33pF Ceramic68pF Ceramic470µF 16V PC Electrolytic220µF 10V Minelectrolytic65pF Trimmer
SEMICONDUCTORSD1,2 1N4148D3 1N4001
2 (M220R)1 (M1M)1 (M4K7)21 (M47K)1 (M470R)2 (M10M)2 (M10K)
1 (WW45Y)1 (WX60Q)1 (WX56L)3 (YR75S)1 (FF13P)1 (WX50E)2 (WX54J)1 (FF15R)1 ULO6G)1 (WL72P)
2 (QL80B)1 (QL73Q)
TR1TR2IC1RG1LD1,2DYI,2, 3,4
BF244ABC5487216Ap.A7805UCMini LED RedDD Display Type A
MISCELLANEOUS51 Sub Min Push SwitchS2,3 4 Pole Slide SwitchXT1 FS Crystal 10MHzP1-4 Pin 2145
DIL Socket 28 -PinLC 10MHz Counter PCBConstructors' GuideLC 10MHz Counter Leaflet
OPTIONALBox M4005Red Display FilterRegulated Adaptor
1 (QF16S)1 (QB73Q)1 (UL64U)1 (QL31J)2 (WL32K)4 (BY66W)
1 UM47B)2 (FH38R)1 (FY78K)4 Pins (FL24B)1 (BL21X)1 (GE55K)1 (XH79L)1 (XK31J)
(WYO2C)(FR34M)(YB23A)
The above parts, excluding Optional items, are available as a kit:Order As LP37S (LC 10MHz Counter Kit)
The following is also available separately although not shown in our1991 catalogue:
LC 10MHz Counter PCB Order As GE55K
21
ZN419/409PRECISIONSERVO
11E-MilerlFJ1Ft.MS* HIGH OUTPUT DRIVE CAPABILITY
* LOW COMPONENT COUNT lArAPPLICATIONS * Motor Speed Control * Servo Control *
IntroductionThe ZN419 precision servo
IC (also supplied as the ZN409) isspecifically designed for usewith pulse width operated servomechanisms, used in a variety ofcontrol applications. A lowexternal component count andrelatively low powerconsumption make the deviceideal for use in model boats,aircraft and cars where batterylife, space and weight are ofprime consideration.
In addition to the role of aservo driver, it is also possible touse the IC in motor speed controlapplications. The device issupplied in a 14 pin DILpackage. Figure 1 shows the ICpinout and Table 1 shows sometypical electrical characteristicsfor the device.
GeneralDescription
A typical control system isthat based on the operation of ajoy -stick to vary the pulse widthof a timing circuit. Largenumbers of pulses are
multiplexed by time division andare used to modulate a radiocontrol transmitter. At thereceiver, the received signal isdemodulated and a train ofpulses is produced to control aservo. The servo consists of amotor driven reduction gearbox
which has a potentiometercoupled to the output shaft. Theservo potentiometer producesan output which corresponds tothe position of the output shaft.The output from thepotentiometer is used to controlthe pulse width of a timing
Parameter Conditions Min Typ Max
Supply voltage 3.5V 5V 6.5VSupply current Quiescent 4.6mA 6.7mA 10mAInput resistance 20k 27k 35kInput current 350µ.A 500µA 650µALower input threshold (Pin 14) 1.15V 1.25V 1.35VUpper input threshold (Pin 14) 1.4V 1.5V 1.6VMinimum output pulse 2.5ms 3.5ms 4.5msOutput saturationvoltage Load current = 400mA 300mV 400mV
Table 1. ZN419 typical electrical characteristics.
22
TIMINGCOMPONENTS
REGULATED2.2 VOLTS E
OUTPUT
POTENTIOMETER& TIMING E
REFERENCE
DIRECTION EOUTPUT
PNP BASEDRIVE
OUTPUTEARTH
OUTPUT 17
OU1TV,an
TIMORWINO -MILE
OU7PlIfwTS
IS VOLTS11131ULATON
"IA*
1 23seas
REGULATOR
14 INPUT
131 DEADBAND
12PULSEEXPANSION
11 LOGIC
3 POSITIVESUPPLY
PNP BASEDRIVE
E1 OUTPUT
Figure 1. IC pinout. Figure 3. Legend on both sides of PCB.
*Li CI
100uF
P130-4
P20 4-
C4
470nF
I 0'
C3I n5F
II
R2
150k
NC
LK3 !
41!
2
13
11
10
OP
ICI
CB
100ef
ZN419/409
(t) TR2
BC 327
TR3
BC327
3
CS
2u2F P12
IDR63304
R4
10121k
C7
100nF
R5
330k
R7
2k2
LK4
OP
R9
4K7
P60
P5O
P7OP9O
PBO
Figure 4. Circuit diagram of servo application.
monostable which forms part ofthe ZN419 IC. An internal pulsecomparison stage compares theinput pulse width with that of themonostable pulse and producesan output which determines thecorrect phase of the on -chippower amplifier. Another outputfrom the pulse comparison
circuit drives a pulse expansioncircuit which expands thedifference between the inputand monostable pulses. Thedifference pulse is used to drivethe motor in such a direction asto reduce the difference so thatthe servo takes up a positionwhich corresponds to that of the
controller joy -stick.In addition to driving servo
motors, the ZN419 can also beused for motor speed control. Inthis application the IC acts as alinear pulse width amplifier. Themotor is driven with a train ofpulses which have a variablepulse width such that the speed
of the motor can be controlledbetween zero and maximum.The ZN419 uses fixed timingcomponents and a fixed resistoris used in place of the servopotentiometer. The centre of therange monostable periodrepresents zero motor speed,and pulses less than or greaterthan this drive the motor in theforward or reverse directionrespectively. A direction outputis produced on pin 4 of the ICand this may be used to control arelay to determine the motordirection. The pulse expansioncomponents should be chosen toprovide a suitable relationbetween the controller joy -stickposition and the speed of themotor.
A `deadband is requiredaround the centre of this range,between the minimum forwardand reverse positions, where nopower is applied to the motor.The IC contains an internaldeadband control circuit and thesize of the deadband isadjustable to suit differentrequirements.
Because of the high currentconsumption of many motors,using the device in motor speedcontrol applications usuallyrequires a separate high currentpower supply to increase theoperating time betweenrecharging the batteries.
IC Power SupplyThe IC requires a 4V to 6.5V
(absolute maximum) single railpower supply which is capableof supplying a current of up to10mA. As the device is primarily
23
w
P1 0
TR
1
8C55
8
+ I=1
Cl
IN 1
00uF
P4 O P13 0-
-P
IO 0 E2 0
R3
R2
22k
22k LK
I
O O
* S
EE
TE
XT
RV
1
220k
I LK
3
C2
NM
lOnF C
4
111:
1+
410
SW
C6
1I 0
0nF
BV
R8
10k
02 7
7 \-
-7D
I1N
4148
VV
IN41
48
12
C3 ii_
__.
11
ICI
ZN
419/
409
til)
TR:
BC
558
R12 4k
7
+1/
1 T P
3 0
TR
2B
C32
7
TR
5Z
TX
650
TR
38[
327
CS
14
I2u2F+ p12
R6
330k
C7
100n
F
--I I
--R
13 1kR
533
0k
P6 0 P5 0 P7 0
R7
2k2
P9 0
R4
0M
UC
8at
NM
100
nF
RV
2220k ^-
10
R9
4k7
P8 0
RIO
4k7
R14
100R
R15
10O
R
R16
100R
TR
6
6071
2
TR
7B
D71
2 aR
L I
+V
2 TR
8B
D71
2
-0
031N
4148
C9
1111
1
]00n
F 047I
1N40
07 L
,A
P 1
I
-0 P14 0
LK4
RI 1
4k7
r 1 1
TR
9M
P5F
114
1 I 1 1
1i
11
11
11
OV
P15 0
designed for use in radiocontrolled models the supply isusually derived from a battery.For reliable operation it isrecommended that highfrequency supply decoupling isused close to the IC to preventhigh frequency voltage spikeson the supply rail.
PCB AvailableA high quality, double
sided, fibreglass PCB withscreen printed legend isavailable as an aid toconstructors wishing to use theZN419 IC. The PCB may beutilised in the construction ofeither a servo driver or a motorspeed control circuit. Figure 2shows the combined circuitdiagrams for both the speedcontroller and servo driveroptions. The PCB legend isshown in Figure 3.
In order to make the PCB assmall as possible, componentsare mounted on both sides of theboard. The PCB is marked "sideA" and "side B" for ease ofidentification. Whenconstructing either circuit, thecomponents mounted on side Ashould be fitted first, followed bythe components on side B. It isnecessary to solder somecomponents on the same side ofthe PCB as they are mounted,instead of the normal 'other side'.This is particularly the case withR5, R8, R11, R13, R14, R15, R16and D4. Protruding componentleads should be cut as close tothe PCB as possible so that theydo not obstruct components onthe other side of the board.
Servo DriverOption
Figure 4 shows the circuitdiagram of the servo driverapplication. If building thiscircuit, reference should bemade to the servo driver partslist only and not to the motorspeed controller parts list whichshows a different set ofcomponent values. Figure 5shows the wiring diagram for themodule when used as a servodriver.
The circuit is primarilydesigned to operate from a 6Vbattery but may be poweredfrom any supply voltagebetween 4V and 6V. Powersupply connections are made toP1( + V) and P2(0V). A pulsewidth modulated input isrequired to drive the module,with a variable pulse widthbetween 0.2ms and 2.5ms asillustrated in Figure 6 and Figure7. A typical test circuit is shown
Photo 1. Top side of servodriver version. Inset: sideview shows that somecomponents are mountedunderneath.
OV I/PP W.M.S'gnalinput(From
receiver)
Figure 5. Servo driver wiring diagram.
Fe-P.W.M.
0.2mS10-04 Min.
2.5mSMax.
20mS Frame
+5V
Figure 6. Control signal.
in Figure 8. Please note: LK1 andLK2 are not fitted for the servodriver application, but both LK3and LK4 should be fitted.
Motor SpeedControl Option
Figure 9 shows the diagramof the motor speed controlcircuit. When building thiscircuit reference should bemade to the motor speed controlparts list only and not to theservo driver parts list whichshows a different set ofcomponent values. Figure 10shows the wiring diagram for themodule when used as a motorspeed control circuit.
The circuit has two separatepower supply rails. A 4 to 6Vpower supply is used for ICI andassociated components, and theconnections from this supply aremade to P1( + V) and P2(0V). Anadditional supply (usuallyprovided by a rechargeableNi-Cd pack) is required for themotor drive circuitry andconnections from this supply aremade to P3( + V) and P4(0V). Thesupply voltage for the motor maybe between approximately 6Vand 8V at continuous currents upto 5A using the componentsspecified; however, highervoltages and currents can beaccommodated using differentcomponent values. In particular,the power handling capability ofrelay FtL1 and resistors R14 - R16
25
Photo 2. Note how the power transistors are mounted on the motor driver option.
20mS Osc.Frame Generator
40018E
Carb
Pin14 = +5VPin 7 = OV
+5V
0.2 to 2.5mSMonostable P.W.M.
Figure 8. Typical test circuit.
6-8VHigh current OVmotor supply +V
(See text)
DCMotor
P4P3
Auxiliarypower supply
output.(See text)
0+V
j OV
6 6P11 P10
0O
P15 0P14
NC NC
J..)
P5 P9
RL1
P1
P1302s1.111 -.P1 P20 ...16114 99 0
Motordirection
links(See text)
OV I/P OV
ICI
1-1
P W.M.S goalinput
(Fromreceiver)
4-6VPowersupply
(See text)
Figure 10. Motor speed control wiring diagram.
Servo Driver Application
Power Supply VoltagePower Supply Current (quiescent)Input Pulse Width
Motor Speed Control Application
Power Supply Voltage
Power Supply Current
Input Pulse Width
LowHighP1 &P3 &
current supply (P1 & P2)current supply (P3 & P4)P2 (quiescent)P4
4V - 6V8mA at 6V0.2ms - 2.5ms
4 - 6V6 - 8V8mA at 6VSee text0.2ms - 2.5ms
Table 2. Specification of prototype.
180r RotationP.W.M. =0.5mS -2.5mS
Figure 7. Servo operation.
should be taken intoconsideration as well as thepower dissipation of transistorsTR5 - TR8. A suitable 12V relayto use in place of RL1 is FJ43W.
Power transistors TR6 - TR8are positioned close to the edgeof the PCB (see photo 2), to allowthe installation of heatsinks asrequired. There is a small 'e onthe legend denoting the emitterof the transistor for referencepurposes. If and to what extent aheatsink is required is reallydetermined by the powerconsumption of the motor beingdriven; higher power motors willobviously require additionalheatsinking. If the model has ametal chassis, it is often possibleto use this as a heatsink for themotor drive transistors. It shouldbe remembered though that thetransistor heatsink tags are atcollector potential and ifnecessary should be insulatedfrom the heatsink using asuitable bush and insulatingwasher such as stock codeWR23A.
The direction of rotation ofthe motor is set by fitting eitherwire link LK1 or LK2. Please noteLK1 and LK2 should never beused together at the same time!LK3 and LK4 are not used in themotor speed control application.
Two preset resistors areused to align the module. Therelationship between the controlstick and the speed of the motoris set using RV1. Because bothforward and reverse motor driveare required, a "no drive" or zeroposition is needed; this isdetermined by adjusting RV2.Some experimentation isnecessary to optimise theparameters of the module forindividual applications.
Finally, Table 2 shows thespecifications for both the servodriver and speed control optionsfrom the prototype module.
26
p 9 ti 0
P1
TR
I
BC
558
CI
100u
F
P4
P13
P10 P2
R3
22k
RI
22k
LK2i
LK I
O
R2
E1
k
RV
I
220k
R8
10k
IIMI
C2
lOnF C
4
I uF 0+
02 7
7S
ZD
IIN
4148
I N41
48
10
12
C3
22nF
13 11
I C I
ZN
419/
409
8 - N
C7 - N
C
14
C5
2u2F
P12
1 D
-0
+V
I
TR
48C
558
R12
4k7
P3 O
+V
2
P11
C7
100n
F
R13 1k
R4
nI k
U
RV
222
0k
NM
C8
MO
O 1
00nF
R10
4k7
TR
5Z
TX
650
R14
cJ
100R
R15
-0
R
R16
100R
TR
680
712
TR
780
712
RL
I
TR
880
712
-o
C9
100n
F
D4
7c -
1N40
07
03I N
4I48
4k7
TR
9H
P51
11 4
11 a
OV
P14 0 P15 0
Photo 3. View on underside of motor driver option.
SERVO DRIVERPARTS LISTRESISTORS: All VeW 5% Carbon Film
MOTOR DRIVERPARTS LISTRESISTORS: All 1/8W 5% Carbon Film (unless specified)
R1,3 Not Fitted R1,3 Micro Res 22k 2 (U22K)
R2 Micro Res 150k 1 (U150K) R2,4,13 Micro Res lk 3 (U1K)
R4 Micro Res 100k 1 (U100K) R5,6 Not FittedR5,6 Micro Res 330k 2 (U330K) R7 Not FittedR7 Micro Res 2k2 1 (U2K2) R8 Micro Res 10k 1 (U10K)R8 Not Fitted R9 Not FittedR9 Micro Res 4k7 1 (U4K7) R10,11 Micro Res 4k7 2 (U4K7)R10,11 Not Fitted R12 4k7 (0.6W 1% Metal Film) 1 (M4K7)R12 Not Fitted R14,15,16 10011(0.6W 1% Metal Film) 3 (M100R)R13 Not Fitted RV1,2 Vert End Preset 220k 2 (UH2OW)
R14,15,16 Not FittedRV1,2 Not Fitted CAPACITORS
Cl Minelect 100µF 10V 1 (RK50E)CAPACITORS C2 Ceramic 10,000pF 1 (WX771)
Cl Minelect 100p.F lOy 1 (RKSOE) C3 Ceramic 22,000pF 1 (WX78K)C2 Not Fitted C4 Minelect 1µF 63V 1 (YY31J)
C3 Ceramic 1500pF 1 (WX70M) C5 Minelect 2200nF 63V 1 (YY32K)
C4 Minelect 470nF 63V 1 (YY3OH) C6,7,8,9 Minidisc 100riF 16V 4 (YR75S)
C5 Minelect 2200nF 63V 1 (YY32K)C6,7 Minidisc 100nF 16V 2 (YR75S) SEMICONDUCTORSC8,9 Not Fitted ICI ZN419/409CE 1 (YH92A)
TR1,4 BC558 2 (QQ17T)SEMICONDUCTORS TR2,3 Not FittedIC1 ZN419/409CE 1 (YH92A) TR5 ZTX650 1 (UH46A)TR1,4 Not Fitted TR6,7,8 BD712 3 (WH16S)TR2,3 BC327 2 (QB66W) TR9 MPSA14 1 (QH600)TR5 Not Fitted D1,2,3 1N4148 3 (QL80B)TR6,7,8 Not Fitted D4 1N4007 1 (QL79L)TR9 Not FittedD1,2,3 Not Fitted MISCELLANEOUSD4 Not Fitted RL I Min 6V 6A Relay (FJ42V)
DIL Socket 14 Pin (BL18U)
MISCELLANEOUS P1,2,3,4,10,11,RL 1 Not Fitted 12,13,14,15 Pin 2145 1 Pkt (FL24B)
DIL Socket 14 Pm 1 (BL18U) LK1 Wire Link See TextP1,2,5,6,7,8, LK2 Wire Link See Text9,12,13 Pin 2145 1 Pkt (FL24B) LK3 Not FittedLK1 Not Fitted LK4 Not FittedLK2 Not Fitted PC Board (GE83E)LK3 Wire Link Fit Wire Link Leaflet (XK49DLK4 Wire Link Fit Wire Link Constructors' Guide (XH79L)
PC BoardLeafletConstructors' Guide
1
1
1
(GE83E)(XK49D)(XH79L)
The following item is not shown in our 1991 catalogue:ZN419 PWM PCB Order As GE83E
28
III
III11IIII
MN IEll
IIMI IIIII111
1
