This is only a preview of the February 1993 issue of Silicon Chip. You can view 54 of the 104 pages in the full issue, including the advertisments. For full access, purchase the issue for $10.00 or subscribe for access to the latest issues. Items relevant to "Build The Electronic Cockroach":
Items relevant to "A Low Fuel Indicator For Your Car":
Articles in this series:
Items relevant to "A 2kW 24VDC To 240VAC Sinewave Inverter; Pt.5":
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DYNAMIC _
E
SERVICING - VINTAGE RADIO - COMPUTERS - AMATEUR RADIO - PROJECTS TO BUILD
Sony's nel/V ca,ncorder
eli,ninates the shakes
PROJECTS FOR
MODEL RAILROADS
YOU COULD
WIN
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15 TEMPERATURE CONTROLLED
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Vol.6, No.2; February 1993.
FEATURES
1 The Silicon Chip 5th Birthday Sweepstakes
Enter & you could win a car - lots of other prizes as well
HERE'S A PROJECT that's just
for fun. It's a robotic car that
behaves just like a cockroach.
Put it on the ground, switch it on
& it heads for a dark corner.
Turn to page 16.
6 Microwave Disinfection Of Medical Waste by J. Cusack & M Taitz
A new technique that doesn't harm the environment
14 Sony's New 8mm Video Camera by Leo Simpson
An active prism system eliminates the shakes
PROJECTS TO BUILD
16 Build The Electronic Cockroach by John Clarke
A robot car that seeks the dark
26 Three Simple Projects For Model Railroads by Terry Mowles
Train controller, traffic light simulator & points controller
MAKE YOUR MODEL railroad
layout more realistic &
interesting by building the
projects described on page 26.
They include a low-cost train
controller, a traffic lights
simulator & a points controller.
38 A Low Fuel Indicator For Your Car by John Clarke
Lights a lamp when it's time to fill up
46 The MAL-4 Microcontroller Board, Pt.3 by Barry Rozema
Step-by-step assembly instructions plus test programs
56 Audio Level/VU Meter With LED Readout by Bernie Gilchrist
A peak hold facility lets you accurately set recording levels
80 A 2kW 24VDC To 240VAC Sinewave Inverter, Pt.5 by John Clarke
Chassis wiring & final check-out
SPECIAL COLUMNS
"'"'7,--
THE SERVICEMAN tried all the
usual short-cuts on a Thorn TV
set this month but still had to fix
the set the hard way. His story
starts on page 64.
42 Computer Bits by Darren Yates
File backups plus a useful utility for LHA & PKZIP
64 Serviceman's Log by the TV Serviceman
A story to support Murphy's Law
96 Vintage Radio by John Hill
The awakening of the Dragon
DEPARTMENTS
4 Publisher's Letter
9 Mailbag
24 Circuit Notebook
54 Back Issues
73 Order Form
74
100
101
102
104
Product Showcase
Ask Silicon Chip
Notes & Errata
Market Centre
Advertising Index
RUNNING OUT OF PETROL is
inconvenient at best & dangerous
at worst. This project reminds
you to fill up by lighting a lamp
when the fuel drops below a
preset level. See page 38.
FEBRUARY
1993
3
Publisher & Editor-in-Chief
Leo Simpson, B.Bus.
Editor
Greg Swain, B.Sc.(Hons.)
PUBLISHER'S LEITER
Technical Staff
John Clarke, B.E.(Elec.)
Robert Flynn
Darren Yates, B.Sc.
Reader Services
Ann Jenkinson
Sharon Macdonald
Sales & Marketing Mgr.
Sharon Lightner
Phone (02) 979 5644
Mobile phone (018) 28 5532
Regular Contributors
Brendan Akhurst
Garry Cratt, VK2YBX
Marque Cro.zman
John Hill Jim Lawler, MTETIA
Bryan Maher, M.E., B.Sc.
Jim Yalden, VK2YGY
Bob Young
Photography
Stuart Bryce
Editorial Advisory Panel
Philip Watson, MIREE, VK2ZPW
Norman Marks
Steve Payor, B.Sc., B.E.
SILICON CHIP is published 12 times
a year by Silicon Chip Publications
Pty Ltd. A.C.N. 003 205 490. All
material copyright©. No part of this
publication may be reproduced without the written consent of the publisher.
Printing: Magazine Printers Pty Ltd,
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Distribution: Network Distribution
Company.
Subscription rates: $42 per year
in Australia. For overseas rates, see
the subscription page in this issue.
Liability: Devices or circuits described in SILICON CHIP may be
covered by patents. SILICON CH IP
disclaims any liability for the infringement of such patents by the manufacturing or selling of any such
equipment.
Editorial & advertising offices:
Unit 1a!77- 79 Bassett Street, Mona
Vale, NSW 2103. Postal address :
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2097. Phone (02) 979 5644. Fax
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ISSN 1030-2662
4
SILICON CHIP
Australia's unseen electronics industry
From time to time, some of our readers express concern that the Australian electronics industry is dying or dead and that this is a symptom of the
problems with our economy in general. Well it is true that our economy
does have problems, in common with many countries around the world.
And it is also true that we have a worryingly high level of imports. But all is
not black; far from it.
Surprising though it may seem, there is a large electronics industry in
Australia although it is very fragmented. This may be news to many of our
readers because there are few Australian brands represented in the consumer electronics market and therefore people naturally assume that the
industry has largely disappeared.
In fact, the amount of electronics manufacturing in this country is much
larger than it ever was in the past, and considerably larger than before 1973
when we had a substantial consumer electronics industry. The biggest
sector is in communications but it is represented right across the board and
a considerable amount is exported. As an example of this, a press release
has just crossed my desk telling of $131 million of exports in 1991 from
IBM's Wangaratta plant - this in spite of rumours in the press about IBM's
long-term plans.
More surprising still, 25% of Australia's exports are manufactured goods
and this has a substantial electronics component. Still not reassured? Go
into a club or casino and see all the poker machines - most are made in
Australia. Or go into an amusement parlour - again, most of the machines
are made in Australia. Or what about your computer modem? Again, it is
probably made in this country. Or what about all the security electronics in
the places where you live, work, shop or play? Again, it is mostly made in
Australia.
I could go on but it is clear that electronics manufacturing is happening
on a large scale in this country and has been for many years. The question
which then arises is should the Government do more to encourage local
industry? The classic answer is to say yes but each time government acts to
help one particular sector of the economy it causes distortions in other
sectors. However, it would be good if government did more to buy locally
made products - too often overseas made goods are favoured.
Overall though, there are considerable grounds for optimism about Australian industry and the electronics industry in particular.
Leo Simpson
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Amy's 1st Primer
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PC - Fastype
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Microwave disinfection
of medical waste
Hospitals & clinics generate large quantities of
potentially dangerous medical waste which
must be safely disposed of. Now there is a new
method whereby the material is first shredded
& then disinfected by exposure to microwave
radiation.
By JOHN CUSACK & MARK TAITZ*
The subject of waste disposal has
become of major concern in industrial countries in recent years. Latent
dangers, such as possible groundwater
pollution, mean that waste should no
longer be simply dumped in landfills.
And public concern about air pollution has put a question mark against
the traditional incineration method
of disposal.
Very few people are aware of the
large quantities of medical waste pro6
SILICON CHIP
It is obvious that uncontrolled disposal and open landfill dumping carry
a risk of disease transmission. But
more than anything else, it has been
the spread of AIDS that has focused
public concern on infection control
and environmental practices within
the health care industry.
Sterilisation or incineration?
The options for treating infectious
waste in the past have been sterilisaduced by hospitals, pathology laboration (by autoclaving) or incineration.
tories, clinics and doctors' practices. . Waste which has been sterilised can
In the United States alone, more than be burnt or shipped to landfills. In the
600,000 tonnes of medical waste are
latter case though, it should be thorgenerated every year by the health
oughly shredded into tiny fragments
care industry. This includes blood and which are unrecognisable as medical
blood products, cultures and stocks waste. This is because many municiof infectious agents, "sharps" (neepal landfills now reject even treated
dles, razors, etc), as well as pathologi- medical waste when it still recogniscal wastes. By the end of the decade,
able.
the amount of such waste is expected
In Australia, most medical waste
to grow significantly.
(called "contaminated waste") is dis-
◄
Left: the microwave disinfection
process is housed in a steel housing
not unlike a standard shipping
container. The waste is shredded,
sprayed with steam & then irradiated
with microwave energy to disinfect it.
The end product is unrecognisable as
medical waste.
k l.r !.. '"'
posed of by high temperature incineration or sealed in yellow plastic
bags which are trucked to municipal
landfills and then immediately buried in designated areas by bulldozer.
The first method brings concern about
air pollution while the second has
concerns about groundwater contamination.
Autoclaves are high pressure steam
vessels, designed originally for sterilising medical instruments. The process involves heating the waste, usually with saturated steam, to 131 °C
and keeping it at this temperature for
up to 45 minutes. It must be continuously checked to see that the material
being sterilised has actually attained
the required temperature, the pressure in the autoclave being about two
bar (ie, about two atmospheres). However, the standard small autoclaves
on the market are not suitable to treat
the large volumes of waste produced
by the health care industry.
Some large hospitals have their own
medical waste incinerators. Initially
designed for the disposal of large
pathological wastes, they are n0t able
to process in an environmentally
sound way today's broader medical
waste stream, which can include about
15% plastics and 20% non combustible material.
Furthermore, due to public concerns about air pollution, the incineration facilities would have to be
equipped with special air cleaning
systems. It is estimated that in the
USA alone, as many as 90% of the
5000 medical waste incinerators currently in operation will have to be
shut down as US clean air standards
become more stringent.
Municipal waste incineration
Another option is disposal in municipal waste incineration plants but
this creates other problems, although
these facilities are usually technically
••••
Six microwave generators, operating at 2450MHz, thoroughly disinfect the
waste material as it passes beneath them on a conveyor.
well equipped for disposing of medical waste.
The main problem lies in the transportation and handling of the waste.
Between being packaged in the hospital and fed into the furnace, there
must be no chance of it going astray,
coming into contact with workers, or
causing any kind of contamination.
Also, municipal solid waste incinerators typically do not operate at temperatures sufficiently high enough to
ensure thorough destruction of all micro organisms.
The microwave solution
ABB Sanitec, Inc recognised that
the medical community, arid particularly large regional hospitals, required
an on-site treatment facility which is
safe, environmentally sound and cost
effective. Their response to this need
was to develop a system which disinfects the waste by heating it with conventional microwaves.
The waste is first shredded into
tiny, confetti-like particles and then
moistened with high temperature
steam. Afterwards, the granulated
material is passed beneath a row of
microwave generators which thoroughly disinfect it. After processing,
the mat~rial is unrecognisable as medical waste and is quite acceptable for
dumping in municipal landfills.
In 198 7, the first medical disinfection system of this kind was placed in
commercial operation at a university
hospital in Germany. ABB Sanitec
has since continued to develop the
technology and units have been delivered to health care institutions and
FEBRUARY
1993
7
temperature throughout. Strip charts
record the variables necessary to substantiate disinfection, while continuous monitoring ensures that the requirements for thorough treatment are
exceeded by a comfortable margin. A
lockable port, just below the shredder, provides easy access for introducing standard testing samples.
Waste volume reduction
The end product is greatly reduced in volume and is unrecognisable as medical
waste. It can also be burnt in a high temperature incinerator to produce steam
for heating or electricity generation.
commercial medical waste disposal
companies in Europe and North
America.
Microwave plant
The waste treatment equipment is
housed in a steel all-weather shelter
measuring 7.2 metres long, 3.3 metres
wide and 2.8 metres high. The total
weight of the unit is about 11 tonnes.
A single electrical mains connection
rated at 75kW for the larger unit and
just one water hook up are necessary.
Enough space must be provided in
front of the inlet hopper to allow transportation and handling. At the output
end, there must also be a hopper for
removing the disinfected material,
which is reduced to about 20 percent
of its original volume. Since there are
no liquid discharges (the small amount
of water used is absorbed into the
waste residue), a sewer connection is
not necessary.
The process does not use chemicals or bleaching agents. Fully enclosed and self-contained, the unit
can be installed outdoors. Many systems are currently being operated in
the loading dock areas of hospitals.
8
SILICON CHIP
An automatic hoist lifts the waste
container and tips the contents into
the hopper at the top of the unit. Before the hopper opens, the air inside
it is treated with high temperature
steam, then extracted through a high
efficiency particulate air (HEPA) filter to emininate any potentially harmful air-borne pathogens. To reduce its
volume, the waste is then shredded
into tiny particles.
The granulated material is automatically conveyed into the treatment
chamber, where it is evenly sprayed
with high temperature steam. The
mixture passes beneath six microwave
generators, each with an output of
1.2kW. These heat the mixture to between 95°C and 100°c and maintain
it at this temperature for a minimum
treatment time of 30 minutes. The
microwave generators are standard
industrial units with an output frequency of 2450MHz. The microwave
generators ensure fast and even heating to the required temperature and
uniform disinfection of each granule.
Sensors and microprocessors control the entire process, ensluing the
proper treatment time and the correct
The end product is a granulated
solid waste which, since it harbours
no risk of infection, is acceptable for
dumping in municipal landfills. Even
vials, hypodermic needles, syringes
and plastic tubing are thoroughly
shredded into tiny fragments which
are unrecognisable as medical waste.
Important for the end disposal is
the fact that the waste is reduced by
this process to only about one fifth of
its original volume. Besides reducing
transportation costs, this also has considerable benefits for eventual dumping in landfills or incineration. It is
also a reason for using the unit at
some hospitals to process waste that
is not defined as infectious by present
regulations.
The heat value of the end product
is also very high. At about 20 MJ/kg, it
is even higher than that of good
firewood. Treated waste is successfully burned in several waste-to-energy plants in the USA and Europe.
Low operating costs
The total operating costs, covering
power, water, labour, maintenance,
spare parts and consumables, are low.
In America, they have been calculated to be about 9 cents/kg, a low
figure compared with the cost of sterilisation or incineration methods.
At present, there are more than 30
units in operation in Europe and North
America. The two models currently
available in Europe are designed for
capacities of 150kg/h and 250kg/h. In
North America, where the units are
also manufactured, only the 250kg/h
unit is currently being marketed. The
smaller unit will become available
during 1993.
Acknowledgment
Our thanks to Asea Brown Boveri
Pty Ltd for permission to reproduce
this article which originally appeared
in the October 1992 issue of "ABB
Review". The authors are employed
by Sanitec, Inc, USA.
SC
MAILBAG
Projects for
marine modellers
I am writing to you on behalf of the
many fine scale marine modellers,
who up till now have been neglected
in your publication. Your articles on
remote control to date have been very
interesting but they don't really cover
my hobby.
I do not know to what extent your
forthcoming articles will cover speed
controls for fine scale marine use. We
don't require very high current capacity but do require smooth operation
in both forward and reverse, with 612V range. Due to the average size of
our vessels, the actual size of the unit
is not so important.
We also need circuits or articles on
making switching and sound units
for marine use; eg, foghorns, steam
whistles, destroyer sirens, etc.
A. P. Cagnacci,
Maritime Model Boat Club,
Mona Vale, NSW.
Comment: Bob Young does intend to
do a version of his speed controller
circuit with reverse, although it will
be some months before it will appear
in the magazine. Thanks also for the
suggestions for articles on sound units
for foghorns, steam whistles, etc.
Help wanted with H&M
model railway controller
Please, please would you print a
request for information regarding the
Hammant and Morgan 5000 Model
Railway Controller.
Mine has an elusive electronic problem which requires a circuit diagram
to solve. I have contacted Hornby Hobbies in the UK (because they took over
H&M) but to no avail.
I was able to contact a very helpful
West Australian enthusiast who supplied me with a Zero One circuit but,
regrettably, it is nothing like the H&M
5000. If any reader out there can help,
I would be most grateful.
Thanks for a great magazine. However, there are still many railway modellers out there hoping to get to grips
with a steam sound simulator that has
everything, including steam sound
(chuff-chuff), steam whistle, a diesel
horn, and a good amplifier that's built
in.
I have built all your previous circuits. The most successful was the
SteamSound Simulator from April
1992. It works well as a train-mounted
system but six out of ten for the "offtrack" conversion.
The Track Tester works well electronically but it must have a good
quality heavy wagon (steel) with individually sprung wheels, otherwise
contact can be lost with the track and
this will give false readings. And nobody, and I mean nobody, can build
the perfect track, taking into account
all the distortions due to heat and
cold.
W. Criddle,
Cooroy, Qld.
Comment: if any reader can help with
a circuit diagram for H&M 5000 model
railway controller circuit, we will forward it on.
Project suggestions for
the magazine
Sometimes it must be very difficult
to choose the projects that you and
your regular contributors design for
the magazine. You can't satisfy everyone all of the time but I must say that
your range over the life of the magazine has been pretty good. Your readers should also make suggestions as
to what they would like but based on
some sort of reasoned argument that
may appeal to a majority of your readers.
I would like to make the following
suggestions:
(1). A moisture meter to indicate
the sap content of wood.
These days, many people are retiring early and taking up the hobby of
woodcrafting and the moisture content/sap content is very important as
to how the wood is to be treated by
the woodworker. Commercial meters
are available but, of course, are pretty
pricey. As an indication, in Tasmania
there are at least three wood guilds
(the one in my area has some 70 to 80
members on its books).
(2). An automatic shut-off valve in
the hot water line to the shower. If my
SILICON CHIP,
PO Box 139,
Collaroy Beach 2097.
memory serves me correctly, a reader
requested such a device a little while
ago. He probably has the same trouble
that so many families have - the young
in the family believing that hot water
costs nothing and that they can stay
under the shower for hours at a time.
I know of no commercial device that
can be set for say a three minute shutoff time (to be variable).
A. Willox,
Launceston, Tas.
Running 3-phase motors from
single phase power
On page 99 of your October 1992
issue, regarding running 3-phase motors on single phase, you said you
didn't think that it was possible.
A friend of mine bought a mediumsize milling machine fitted with 3phase motqrs and he lives in an area
where · only single phase power is
available. A local electrician made a
low-cost modification to allow them
to work on single phase. I don't know
how efficient this is, and I would regard it as purely an emergency measure, but the fact is it does work.
I asked him about starting and he
said that these seemed to start OK.
However, he had previously used a
similarly modified 5hp 3-phase motor on another machine that occasionally didn't start, in which case he
would switch it off, turn the motor
slightly, and it would go next time.
By coincidence, this afternoon I saw
an advertisement for books, including one titled "How To Run A 3-Phase
Motor From A Single Phase Supply".
It was from Plough Book Sales, PO
Box 14, Belmont, Vic, 3216.
R. Heinke,
Quorn, SA.
Comment: it seems as though a
number of schemes have been used in
the past to allow a 3-phase motor to
run from a single phase supply. However, most of these are fairly "irregular" in their concept and would not
produce the same efficiency in the
motor. There is also a difficulty with
reliable starting. We still regard the
principle as not being a good one but
cannot deny that it can be done.
FEBRUARY
1993
9
Build the Best - Forget the Rest!
Top quality kits plus three exciting new releases!
LED VU METER
Q
EXCLUSIVE TO US!
LOW FUEL INDICATOR Q
If you've ever run out of fuel in your car, you'll see the value of
Designing your own Audio system
this low-cost kit. It lights a 12V warning lamp when the fuel
or just updating old style equipment drops below a pre-determined level. Harder to ignore than your
that uses an analogue VU meter,
standard gauge, the light could save you a great deal of
this unit offers the advantages of
inconvenience and embarrassment.
fast response and peak hold display. Comes with PCB, case, 12V panel
Comes with PCB, red,
mount lamp and all necessary
yellow and green LEDs
components, including auto
plus all necessary
connectors for ease of installation.
components and hardware.
Cat K-4210
• Shortform kit
111
• 12 LEDs (red, yellow & green)
• Can operate from a
II
supply voltage
of between 11-40volts
Feb '93
.
Cat K-5370
111 ~~~
= ; ,, ,, D
Feb '93
,-,~
.,;
1'\11 $1495
;__, .·,-;:~"?-~
VK POWERMASTER MK 2
The new and improved Powermaster Mk2 kit gives you all the
power you'd ever want for transceiver and bench-top power
installations. Its flexible design allows you to choose the
appropriate transformer for your desired power output level,
opening up many possibilities for customising your own
particular installation.
For example:
CURRENT RATING:
SURGE
CONTINUOUS
PEAK
TRANSFORMER
(1 MINUTE)
(PULSE)
BA
10A
20A
25A
25A
15A
20A
25A
5A
M-2000
M-2010
UPGRADED
M-2010
For those who remember the original Powermaster, the addition
of a 20A panel meter to the kit plus provision for an optional
12V cooling fan will make even higher power configurations
possible with perfect safety. On the cosmetic side, the supplied
case is now an attractive black powder-coated steel unit - an
advance over the previous bare aluminium box. Other
improvements include: A front-panel overload protection reset
switch and a primary slow blow fuse with finger proof fuse
holder. The ~it includes all components (excepting those that
depend on your choice of transformer), all hardware and a
pre-punched silk-screened chassis.
Cat K-3400
<at>
JAN'93
QQQ
;,;;,<K~
""
i :Jf.,1
[z]
PLEASE CHECK YOUR NEAREST STORE FOR AVAILABILITY.
AS SOME KITS MAY STILL BE IN PRODUCTION.
FM RADIO
. ~ ~ -i p
2 9 95
r;(!'J:..,~
RF VIDEO MODULATOR
These are nearty·$20 anywhere else! Convert your video or
computer output to standard TV input with this Video
Modulator. All the hard work's done... it comes pre-tuned and
aligned and can be switched to VHF channel 1 or 0. Has RCA
socket and built-in voltage regulator. (Complete with
Data Sheet).
Cal K-6043
Unbelievable Low Price!
50MHz FREQUENCY COUNTER QQ
Low in cost, yet giving high accuracy, this low-cost 50MHz
frequency counter gives you just about every measurement
you need in this category - for far less
money than comparable
commercially available counters.
Comes complete with all
components, PCB, hardware,
LED display, case, plug pack & a
pre-punched silk screened
front panel.
Cal K-7337
\OM~, I l tOU IN(Y (0U N1!1
10
SILICON CHIP
1fl,,,
New to ktt buUd;ng? Then t~ th;s os ,
an ideal first project! This simple FM
~- . • ~.-/"
radio receives all of your favourite FM
.,.. / _,,,
stations, uses only two low-cost
, ,.,,-, $
Integrated Circuits (ICs) and runs off
a 9V battery. It's a great 'hands-on' way to
learn about Radio Frequency (RF) circuits and Audio
Frequency (AF) amplifiers. This short-form kit comes with FM
radio IC & Audio IC, PCB, speaker, components and other
hardware.
•
Cal K-5014
• Battery not included
Nov'92
With sound, Cat L-5226
6995
5
Huny in for these! Due to a scoop
~ - -..
purchase, we have limited stocks of these -------=:::-;; !!:::::;::::i;tr,,,;,,::::---12cm (4.8") black & white NTSC video
'••·==:::=:,i==============:••
monltors-suitableforuseinsecurity ~ C
e,~ , 0
---==:,,,,,E{~iil
systems or for any project you might
;;, oC~~'.J
··
dream up!
...-:::,::noV
2 2
Cat L-~ ~
VU"
.
12cm (4.8")
NTSC, 1.5V p.p B&W
Horizontal15.7KHz
Vertical- 60Hz
1
2
3
a
5
6
7
B
9
*
0
t1
0
digitor
DIGITOR HANDS-FREE
55MHz TRANSCEIVER
DIGITAL ACCESS
KEYPAD
With up to 500m range and no
license required, this Is an ideal
local-area or first-time-user
transceiver. Powered by a 9-volt
battery, It comes complete with
belt clip and an earpiece/tieclasp microphone for handsfree use. Has selectable pushto-talk or voice activation and
a sensitive dual conversion
receiver.
Cat D-1095
A digital keypad with raised
keys that can be fitted to alarm
systems, security door
applications, etc. It comes with
a mounting block and is
finished in brushed stainless
steel.... so It looks great. Ifs
fitted with a tamper switch for
added security.
Cat L-5284
$6995ea
sAVE $20
. . ·, . :,
.
. · ., •,:
•,
Horizontal resolution:
525 lines
Audio output (Electret mic.): 170mW 16OHM
(L-5226 only)
Dimensions:
195mm L x 145mm
W x 140mm H
Power Source:
13.5-15V DC,
600mA
Spec1f1cahons:
CRT size:
Video Input:
Scanning Frequency:
♦--: :::-.:·:·.:
$4995
ANALOGUE
MULTIMETER
A hi,9h quality multimeter with a
3 ½ mirrored scale and 25
ranges plus DB. Safety features
include overload protection as
well as diode & fuse protection.
In addition, it has an automatic
TR (transistor) quality and type
checker (ie - PNP or NPN), 1.5 &
9V battery checker, continuity
· test and temperature
measurement (-20°C to 150°C).
Comes complete with a
temperature probe and tilt
stand.
AC VOLTAGE
• 25 ranges plus DB
FINDER
• Sensitivity: 20,000 Ohm/V
Now there's no need to put'
• DC Volts: 0.1, 2.5, 10, 50, 250,
yourself at risk! This device
1000V
detects the electromagnetic
• AC Volts: 10, 50, 250, 10OOV
field surrounding cables,
• DC Current 50uA. 2.5mA.
sensing any AC voltage above
25mA. 250mA. 10A
120 volts and warns you with
• AC Current: 10A
both an LED and an audible
• Resistance: x1, x10,
"buzz". At this low price, there's
x1 K,x1 OK
no excuse for not having one!
• Temperature: -20°C to 150°C
CatQ-1531
$
CatQ-1028
1695
$6 9 95
FEBRUARY
1993
11
A Wealth of Knowledge
(at bargain prices)!
A Small Sample Of Our Amazing Range Of Technical Books:
Electronic Tips & Techniques
Mastering IC Electronics
Wire & Cable For Electronics
Oscillator Circuit Encyclopaedia
Amplifier Circuit Encyclopaedia
Regulated Power Supplies
Encyclopaedia Of Electronic Circuits Vol. 2
Encyclopaedia Of Electronic Circuits Vol. 3
Encyclopaedia Of Electronic Circuits VoL 4
Troubleshooting With Oscilloscopes
Basic Electronics Theory
101 Optoelectronic Projects
PC Architecture & Assembly Language
Electronic Circuit Cards & Surface Mount Technology
The Complete PC Memory Manager
RF Interference Handbook
RS-232 Made Easy
QUE Repairing & Upgrading PCs
IBM PC Configuration Handbook
~
« ~·. .
C
~
The Art Of Science
Engineer's Notebook
The Screwdriver's Expert Guide
Understanding CB Radio
~-- =
()
)'a~_/
_, ~~\~p:1.:~-·\
,_;7-.
~~~';jrj
~ (, _,. '1 (' ~ /-~®-.,(
~-=- =
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,
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0
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A
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
Cat
B-1600
B-1612
B-1618
B- 1742
B- 1744
B-1746
B-1758
B-1758
B-1758
B-4801
B-1615
B-1617
B-6099
B-1620
B-6097
B-2401
B-6098
B-6195
B-6203
B-1300
B-1500
B-2324
B-2327
$33.95
$39.95
$49.95
$29.95
$29.95
$24.95
$54.95
$56.95
$59.95
$39.95
$39.95
$29.95
$28.95
$49.95
$39.95
$26.95
$49.95
$69.95
$59.95
$37.95
$24.95
$19.95
$39.95
_-. -, J
t' . :.'~,Gr:)fj .
11
~
/~
,,
•I'' ''
!
I
MAJOR DICK SMITH ELECTRONICS AUTHORISED STOCKISTS:
NSW: ARMIDALE: New England Electronics 711655 BALLINA: Ballina Electronics 867022 BATEMAN'SBAV: Baycity Sight & Sound 725030 BATHURST: Electronic Frontiers 323933 BOURKE: Countrywide Services 722150 BOWRAL: Bowral
Electrical Supplies 611861 BROKEN HILL: Hobbies & Electronics 884098 COOTAMUNORA: CoolalTiundra Music & Lite 422561 COFFS HARBOUR: Coifs Harbour Electronics 525684 DENILIOUIN: Deni Electronics 813672 DUBBO: Chris's Hi Fi
828711 FORSTER: Forster Village Electronics 545006 GDULBOURN: Tunlive 22 1288 GRAFTON: Repair.; & S res 421911 GRIFFITH: Miatronics 624534 INVERELL: lnverell Electronics 221821 KATOOMBA: Ni~ara Photo & w,ns 822800
1
3
=:~~~ :f~~~irUi3r!~~~n~;-;~i~"1~i~ii
RIDGE: .
.
7~gJiL:Ai:iRr:~~n~:,~~fu~1t1i~~~rE2i~ ii1X~"il.1':~tri?.~tr:1~6bfe~:f3~
Electronics 210722 PARKES: Strad Music Ctr 623366 POOT MACQUARIE: Hastings
: Silicon Crafts 784101 TAREE: ~anning Electronics 512233 ULLADULLA: Coastal Electronics 553989 WAGGA WAGGA:
Phillips Electronics 216558WALGETT: walgen Electronic Centre 281111 WINDSOR: Hawkesbury Electronics 776722 VASS: wannington Electrical 261411 YOUNG: Keith Donges Electronics 821279 VIC: ARARAT: Jerram Electronics522345
BAIRNSOALE: LH & LM Crawford 525677 BENALLA: North East Electronics 622710 CASTLEMAINE: Inspect Electrics 723773 COLAC: Colac Electronics 312847 ECHUCA: Gilmour Electronics 822956 MILDURA: Pullman Auto Pro 232882
MORWELL: Roytaine Ply Ltd 339458 ROSEBUD: Seatech Vic Ply Ltd 822225 SHEPPARTON: Andrew Guyan Electronics 219497 SWAN Hill: Nyah District TV Service 329303 ST. ARNAUD St. Arnaud Appliances 951069 WARRAGUL: Roylaine
234255 WARRNAMBOOL: KoroitSt Elec Services 627417 WONtHAGGI: South Gippsland Photo Service 721411 OLD: AVR: Delta Electrix 831566 BLACKWATER: Cool Tronics 825827 BOWEN: Delpro Agencies 8634T/ BUNOABERG: Bob Elkin
Electronics 521785 CALOUNDRA: Electro-mart 918533 DALBY: Hobby & Electronics 625770 EMERALD: Cooltronics 825222 GLADSTONE: Electronic Enterprises 726660 GOONDIWINDI : CTW Electronics 713411 INGHAM: Masons Electronics
763188 INNISfAIL: lnnisfail Hi-R 612014 KINGAROV: MD & MM Siegle 624535 LONGREACH: Longreach Sound & Communications 583307 MACKAY: Stevens Electronics 511723 MARVBOROUGH: Keller Electronics 214559 MOSSMAN:
Mossman Electronics 982200 MT ISA: Outback Electronics 433331 NAMBOUR: Nambour Electronics 411966 PIALBA: Keller Electronics 283749 STANTHORPE Granite Belt Communications 813333 TAS: BURNIE: Electronic Ci~ 314760
1
1
4
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~~~~ri~~:
732531
~:~~~~I~~:
~6~22c~i~~~e~~J:~t~~rc~'"st~~-~~riro~'."o~r~?t~h:T2\
12
SILICON CHIP
~o~~:~
~ir :t2'lir~~
~I:r ~..'.;~~7i.
EXTRA! EXTRA! NEWS FLASH!
5mm LEDs - Now In Bluel
Jazz up your projects with a few of these great new 5mm
blue LEDs!
llf.ld
cat z-4oos
RBLL Electrolytic Capacitors: "'"
Item
MKT CAPACITORS:
Price
Item
0.001 mFd 100 WV 5%
0.0012 mFd 100 WV 5%
0.0015 mFd 100 WV 5%
0.0018 mFd 100 WV 5%
0.0022 mFd 100 WV 5%
0.0033 mFd 100 WV 5%
0.0039 mFd 100 WV 5%
0.0047 mFd 100 WV 5%
0.0056 mFd 100 WV 5%
0.0068 mFd 100 WV 5%
0.0082 mFd 100 WV 5%
0.01 mFd 100 WV 5%
0.012 mFd 100 WV 5%
0.015 mFd 100 WV 5%
0.018 mFd 100 WV 5%
0.022 mFd 100 WV 5%
0.027 mFd 100 WV 5%
0.033 mFd 100 WV 5%
0.039 mFd 100 WV 5%
0.047 mFd 100 WV 5%
0.056 mFd 100 WV 5%
0.068 mFd 100 WV 5%
0.082 mFd 100 WV 5%
0.1 mFd 100 WV 5%
0.12 mFd 100 WV 5%
0.15 mFd 100 WV 5%
0.18 mFd 100 WV 5%
0.22 mFd 100 WV 5%
0.27 mFd 100 WV 5%
0.33 mFd 100 WV 5%
0.39 mFd 100 WV 5%
0.47 mFd 100 WV 5%
1.0 mFd 63 WV 10%
1.5 mFd 63 WV 10%
Cat-R 3000
Cat-R 3001
Cat-R 3002
Cat-R 3003
Cat-R 3004
Cat-R 3006
Cat-R 3007
Cat-R 3008
Cat-R 3009
Cat-R 3010
Cat-R 3011
Cat-R 3012
Cat-R 3014
Cat-R 3015
Cat-R 3016
Cat-R 3017
Cat-R 3018
Cat-R 3019
Cat-R 3020
Cat-R 3021
Cat-R 3022
Cat-R 3023
Cat-R 3024
Cat-R 3025
Cat-R 3026
Cat-R 3027
Cat-R 3028
Cat-R 3029
Cat-R 3030
Cat-R 3031
Cat-R 3032
Cat-R 3033
Cat-R 3037
Cat-R 3038
.35
.35
.35
.35
.35
.35
.35
.35
.35
.35
.35
.35
.35
.35
.35
.40
.40
.40
.40
.40
.40
.40
.45
.45
.50
.55
.55
.65
.70
.80
.95
1.05
1.45
1.85
10 or
more
0.1 mFd50V
0.22 mFd 50V
0.33 mFd 50V
0.47 mFd 50V
0.68 mFd 50V
1.0 mFd 50V
2.2 mFd 50V
3.3 mFd 50V
4.7 mFd 50V
6.8 mFd 50V
10.0 mFd 35V
22.0 mFd 35V
33.0 mFd 25V
47.0 mFd 25V
68.0 mFd 25V
100 mFd 25V
Cat-R
Cat-R
Cat-R
Cat-R
Cat-R
Cat-A
Cat-A
Cat-R
Cat-R
Cat-A
Cat-R
Cat-R
Cat-R
Cat'R
Cat-A
Cat-A
ELYSPRAY COMPUTER
CLEANING SPRAYS
$3.95
$3.95
$3.95
2.2mm x 7.5M #3 .
2.5mm x 7.5M #4 ·
Cat N-1808
Cat N-1809
$14.95
$14.95
High security - low price!
Ideal for maki ng up keyring transmitters or other one-button
remote controls, they come complete with battery clips and a
pocket clip on the back.
$2 25
~
.-.-
$1
$13 95
Cat N-1804
Cat N-1805
Cat N-1807
PLASTIC 'MINI TRANSMITTER' CASE
hardware below:
Q
.31
.31
.31
.31
.31
.31
.31
.31
.38
.38
.46
.46
.46
.46
.53
.60
2.5mm x 1.5M #4
3.7mm x 1.5M #5
2.2mm x 1.5M
Just in case ..
First pick the appropriate PCB, then all you need is the
'Momentary On'
push-button switch
.45
.45
.45
.45
.45
.45
.45
.45
.55
.55
.65
.65
.65
.65
.75
.85
E!!!!!!dj
Pro Wick
Pro Wick
Unfluxed
Nude Wick
Pro Wick
Pro Wick
12 Volt Battery
10 or
more
.24
.24
.24
.24
.24
.24
.24
.24
.24
.24
.24
.24
.24
Keep It Clean!
.24
.24
.28
.28
.28
Grime is the natural enemy of all electronic
.28
~ ~ equipment -keep your computer spotless
.28
-~ wit I I these fine Elyspray products.
.28 ~ ✓
.28
·- - Computer Keyboard & Case Cleaner Cat N-3001
.31
,.....,.,. _,; Computer Screen Cleaner
Cat N-3002
.31
.35 lll!ll!!!!!!I
.38
.38
Suck Up That Solder!
.46
.49
DESOLDERING BRAID
.56
De-solder a job in just seconds - this stuff slurps it right up!
.66
.73
Pro Wick
1.5mm x 1.5M #2
Cat N-1802 $3.75
1.02
Pro Wick
2.2mm x 1.5M #3
Cat N-1803 $3.75
1.30
MAKE UP YOUR OWN MINI TRANSMITTER!
Cat S-3335
4800
4802
4804
4806
4808
4810
4812
4814
4816
4818
4820
4822
4824
4826
4828
4830
Price
s49s
cat P-7572
ALARM BARREL SWITCHES
Ideal for use on alarms or any project where security is
important, these quality keyed switches will keep out
unauthorised users. ~
Standard keyed
Cat L-5290 $9.95
Mini Standard keyed
~ Cat L-5295 $9.95
Tubular-keyed
Cat L-5291 $12.95
Mini Tubular-keyed
Cat L-5296 $10.95
.
•P""""\'!a
FROM $C)95
(Additional Battery Clip Cat H-2496 $1.95)
DS XPRESS PHONE & MAILORDER SERVICE
Outside Sydney (FREE Call) 008 22 6610 Sydney And Enquiries - (02) 888 2105
FAX: (02) 805 1986 or write to DS XPAESS, PO BOX 321 N/AYDE NSW 2113
All Major Credit Cards Accepted. 0/Nite Courier Available.
STORE LOCATIONS:
NSW • Albury 21 8399 • Bankstown Square 707 4888 • New Store Location - Blacktown Shop 301, 22-24 Patrick St 671 7722 • Brook vale 905 0441 • Bondi 387 1444 • Campbelltown 27 2199
• Chatswood Chase 411 1955 • Chu llora 642 8922 • Gore Hill 439 5311 • Gosford 25 0235 • Hornsby 477 8833 • Hurstville 580 8622 • Kotara 56 2092 • Uverpool 800 9888 • Maitland 33 7868
• Miranda 525 2722 • Newcastle 611896 • North Ryde 878 3855 • North Sydney (Greenwood Plaza) 964 9467 • Orange 618 400 • Parramatta 889 2188 • Penrith 32 3400 • Railway Square
211 3777 • Sydney City 267 9111 • Tamworth 88 1711 • Wollongong 28 3600 ACT• Belconnen (06) 2531785 • Fyshwick 280 4944 VIC• Ballarat 31 5433 • Bendigo 43 0388 • Box Hill 8900699
• Coburg 363 4455 • Dandenong 794 9377 • East Brighton 592 2366 • Essendon 379 7444 • Footscray 689 2055 • Frankston 783 9144 • Geelong 232 711 • Melbourne City 399 Elizabeth St
326 6088 & 246 Bourke St 639 0396 • Richmond 4281614 • Ringwood 879 5336 • Springvale 547 0522 QLD • Booval 282 6200• Brisbane City 229 9377• Buranda 391 6233• Cairns 311 515
• Capalaba 245 2870 • Chermside 359 6255 • Maroochydore 791 800 • Rockhampton 27 9644 • Southport 32 9033 • Toowoomba 36 4300 • Townsville 72 5722 • Underwood 341 0844 • SA
• Adelaide City 2321200 • Beverley 3471900 • Elizabeth 255 6099 • Enfield 280 6088 • St. Marys 277 8977 WA• Cannington 451 8886 • Fremantle 335 9733 • Perth City 481 3261 • Midland
250 1460 • Northbridge 328 6944 TAS • Hobart 31 0800 • Launceston 344 555 NT• Stuart Park 81 1977
STORES ACROSS AUSTRALIA AND NEW ZEALAND
8 1448
FEBRUARY
1993
13
Sony's new camcorder
stops the shakes
There are many camcorders on the Australian
market & they all have the same problem: when
you use them in telephoto (zoom) mode, the
image tends to shake. Now Sony has released
this new model which modulates an active prism
to cancel the shakes.
By LEO SIMPSON
If you haven't had a look at camcorders recently then it is likely to be
a revelation to see just how small they
have become while continuing to provide more and more operating features. Essentially, the new Sony CCDTR805 offers just about every currently
available feature you could think of
plus two that are not available in other
cameras - wobble cancellation using
an active prism and a zoom microphone system.
Before we go on to describe these
two key features, let's just briefly discuss the camcorder itself.
As you would expect, the CCDTR805E is based on Sony's 8mm video
cassette format which is virtually the
same size as a standard audio cassette
and thus it allows a very compact
camera. The cassette is loaded and
unloaded by a motor drive system
and it can record or play for 90 minutes in single play mode and 3 hours
in long play mode. Naturally, if you
were recording under battery power
you would need to change the battery
several times during the course of a
single cassette.
Dimensions of the camera are 109 x
106 x 189mm (W x H x D) and it
weighs just over 1.1kg with the cassette loaded and a battery pack clipped
on. With these small dimensions and
light weight it really is quite comfortable to use.
The image device is a CCD (charge
coupled device) which is 8.5mm
square with 470,000 pixels (picture
elements). The recording system is
PAL to CCIR standards or His which
is a system separating the luminance
from the chrominance for better video
bandwidth. To take advantage of the
better pictures of the HiB system
though, you also need a video monitor which can accept S-video connectors (4-pin mini DIN).
The sound recording system is
stereo via the inbuilt stereo/zoom
microphones or via external microphones (connected via a stereo mini
jack plug).
As is standard with most camcorders, the electronic viewfinder is
black and white and it has a number
of tell-tales on its screen to tell you
about operating modes such as shutter speed, lens setting, battery condition and so on.
Shutter speeds are selectable over a
wide range: 1150th, 1/120, 1/ 250, 1/
1000, 1/2000, 1/4000 and 1/10,00oth
of a second. Naturally, the higher
speeds can only be used if you have
very bright lighting but they certainly
reduce blurring of fast moving objects.
This camera can be used in really
dim conditions and is rated down to 3
lux (candle light) and up to 100,000
lux (bright sunlight). Naturally, for
the most noise-free pictures, you
should use the brightest light available.
Filled with liquid having a high
refractive index (the same refractive
index as that of glass)
Lens
'--v----"'
Active prism
Apex angle of the active prism is
changed (optical axis is bent).
Fig.1: these diagrams show how a liquid-filled active prism is bent to change the optical path & thus compensate
for hand movement or other vibrations. The prism will deflect the light path by ±3° in both the horizontal &
vertical directions to cancel pitch & yaw.
14
SILICON CHIP
Sony's new CCD-TR805E camcorder has a 2-speed lOx power zoom, a stereo
zoom microphone & a multi-directional remote control. The outstanding feature
though is the "steady shot" image stabilisation system which provides wobblefree pictures, even in telephoto mode.
The CCD-TR805E has facilities for
white balance plus automatic OT
manual focus, manual exposure control, video titling, time and date (including international and summer
time), fade-in and fade-out (normal
and mosaic) and edit search. The last
feature allows you to view the last
few seconds of your last recorded
scene.
The automatic focusing system is
very effective and works well through
windows, even though Sony state that
you will probably have to resort to
manual focusing in this condition.
Remote control
Now why would you want remote
control on a camcorder? It might
sound like a gimmick but there are
two good reasons to have it. First, the
camcorder is crowded with controls
and so it is handy to have a remote
control when playing back through a
monitor rather than having to sit next
to the unit. Second, the remote control allows you to set up the camera
on a tripod and then include yourself
in the recording. The remote must be
the smallest which is physically possible. It uses a lithium battery and is
not much larger than the UHF single
button remote controls used for car
burglar alarms.
The zoom microphone also might
be regarded as being of doubtful utility until you think seriously about it.
The TR805E has three microphone
meshes on the front but there are actually four electret microphone in-
serts inside the camera body. When
the lens is at its wide-angle setting,
the microphone inserts work in stereo,
picking up sound from a wide area to
the right and left of the camera. However, as you use the 10x zoom and the
lens moves from wide-angle to telephoto mode, the stereo pickup pattern then becomes inappropriate. You
need to pick up sound from a narrow
angle in front of the camera while
sounds to the left and right then become a nuisance, masking the sounds
you want.
Hence, the Sony TR-805E gradually changes the sound pickup from a
wide-angle (cardioid?) stereo pattern
to a unidirectional mono pickup. In
practice, it is a very useful feature and
one which you won't think about at
all once you have used it.
Image stabilisation
And now we come to the "steady
shot" image stabilisation system
which sets this camcorder apart from
others. Some readers will be aware
that are several image stabilisation
schemes for camcorders already in
the marketplace. The first of these is a
motor-driven gimbal system whereby
the lens and CCD imager together are
mechanically stabilised against hand
movement.
The other methods involve manipulating the signal from the CCD image
so that the effective picture area of the
CCD is moved to compensate for hand
shaking. In effect, the full picture area
of the CCD is not used which means
that the resolution is slightly reduced.
And then there is Sony's active
prism method which is clever indeed.
The active prism consists of two glass
panes connected with bellows and
filled with a liquid having the same
refractive index as glass. The prism is
placed in front of the normal lens and
can be bent horizontally or vertically
to keep the image centred on the CCD
at all times.
According to Sony's literature, the
front glass pane has a coil system to
compensate for pitch {vertical movement) while the rear glass pane has a
similar coil system to compensate for
yaw (horizontal movement). The optical axis can thus be moved by a total
of ±3° horizontally and vertically to
compensate for hand shake.
Two systems of movement detection are currently employed in camcorders with movement compensation. The first detects the motion and
direction of the image deflection by
using memory and image processing
information from the CCD and this is
most appropriate to the CCD image
manipulation scheme mentioned
above. However, it does not work well
with Sony's active prism because it
introduces a 1-frame lag (ie, 1/5oth of
a second).
Hence, the method used for movement detection on the TR-805E
camcorder involves a triangular pole
with a piezoelectric transducer on
each face. One piezo device is energised at 25kHz which causes the others to produce the sarrie signal when
the camcorder is at rest. When movement occurs, there will be a difference between the two transducer signals and this is amplified and processed by the unit's internal microprocessor to produce the correction
signals applied to the active prism
coils.
A large or slow movement of the
camcorder is assumed to be a normal
panning or tilting operation and is
therefore ignored by the microprocessor.
The description above is considerably simplified compared to the actual operation of the active prism but
it summarises the principle involved.
The system certainly works well and
this can be simply demonstrated by
turning it off after which you will
find just how much you do shake
about, especially when the camcorder
continued on page 78
FEBRUARY
1993
15
,..,~
Buildlllis
Electronic Cockroach
Here's a project that's just for fun. It's a
robotic car that behaves just like an
electronic cockroach. Put it on the
ground, switch it on & it heads for a
dark comer.
By JOHN CLARKE
In the early days of semiconductor
electronics, electronically controlled
toys were very popular. For the first
time, it was possible to build in complex control systems that were either
too difficult or impossible using mechanical techniques.
Those early models were quite expensive due to the high cost of the
16
SILICON CHIP
parts but, of course, this situation no
longer applies. Parts are now quite
cheap and low-cost motors and wheels
are easily obtainable from hobby shops
and parts retailers. This electronically
controlled car, dubbed the "E,lectronic
Cockroach" (because it seeks the dark),
is an inexpensive toy that will give
you a chance to combine your elec-
tronics skills with a few simple mechanical skills. It uses two ICs which
cost around $1 each and two motors
which are only $3.95 each.
What does it do?
Basically, the Electronic Cockroach
runs along the floor and steers away
from the light. It runs straight ahead if
there is equal light intensity on each
side of the vehicle but if one side is
darker than the other, the vehicle
steers fowards the dark.
A real cockroach has six legs but
our electronic version has to rnake do
with three wheels - two at the front
and one at the back. The two wheels
at the front are independently driven
by separate motors while the wheel at
the rear simply trails behind. This
rear wheel is mounted on a swivel
from the motor. In our circuit, each
motor is driven by a pulse width
modulated (PWM) voltage signal
rather than by a continuous DC voltage as in the original idea.
This technique ensures that the
peak vpltage is always applied to the
motor, regardless of the speed control
setting. Rather than varying the DC
level, the speed of the motor is set by
varying the pulse width.
TRIANGLE
WAVEFORM
PIN 6, IC2a
+6V
APPLIED
MOTOR
VOLTAGE
ov
LOW BACK EMF
TRIANGLE
WAVEFORM
PIN 6, IC2a 1-+-- -~ - - - , - - + --
Speed regulation
--'r
+6V1-.----,
APPLIED
MOTOR
VOLTAGE
ov
Fig.1: the motor speed in the
Electronic Cockroach is controlled by
comparing the motor's back-EMF with
a triangle waveform to derive a
voltage pulse train. If the motor slows,
the back-EMF falls & the pulse length
increases to bring the motor back up
to the correct speed.
axle and can rotate through a full 360
degrees.
At the front of the vehicle are three
light detectors (LDRs), one in the centre facing straight down and two at
the corners facing to either side. These
LDRs measure the light intensity and
provide control signals to switch the
motors on and off accordingly.
Incidentally, the idea for this car
comes from Shaun Williams from
Alawa, NT. He originally sent in a
circuit for a vehicle which used LDRs
and a motor gearbox drive for the two
front wheels. We thought that the idea
was good enough to develop further,
while reducing the cost as much as
possible.
In particular, we wanted to eliminate the motor gearbox drive. Although being the best way to drive the
vehicle, it would have added about
$40 to the project and this would have
reduced its appeal. Eventually, we
decided to drive the front wheels from
the motors via rubber bands, a technique that's cheap but effective.
Because the drive ratio from the
motor to the wheel is not as high as
that available from a gearbox, the motor drive circuitry was also redesigned
to obtain the greatest possible torque
Another worthwhile feature of the
circuit is speed regulation. This helps
the motor to maintain its speed even
if the gradient changes or the motor is
loaded due to the nature of the "terrain" (eg, thick carpet).
Fig.1 shows the basic principle of
the feedback control. What happens
is that the circuit monitors the backEMF generated by the motor. BackEMF is the DC voltage generated by
the motor to oppose the current
through it. The faster the motor spins,
the greater the back-EMF.
This back EMF is compared with a
triangle wave generated by an oscillator and the resulting pulse waveform
then drives the motor.
When the motor is running at high
speed, (ie, when it is unloaded), it
produces a high back-EMF and so the
voltage pulses applied to the motor
are quite narrow. However, if the motor is loaded, it slows down and the
back-EMF drops. The circuit then automatically increases the width of the
pulses (and thus the average voltage)
to increase the motor speed.
Circuit details
Let's now take a look at the circuit
details - see Fig.2. Although at first
sight it appears to use a lot of op
amps, these are all contained in two
quad comparator ICs (ICl & IC2)
These comparator ICs are LM339
devices which can operate down to
2V. T~eir outputs are open collector
which means that you must to use a
pull-up resistor to obtain a high output. The advantage of open collector
outputs in our circuit is that they can
be connected together as OR gates.
The circuit is also somewhat simpler than it first appears because the
two motor drive circuits are identical.
IClc, IClb, ICla and Ql drive one
motor (Ml), while ICld, ICZb, ICZc
and Q2 drive the other (M2).
ICZa is the triangle wave generator
PARTS LIST
1 PC· board, code 08310921,
207 x 83mm
2 Johnson 170 motors (available
from model shops)
8 2mm screws and nuts
2 42mm diameter plastic wheels
(Aristo-craft or equivalent)
1 150mm-length of 1/8-inch
brass tubing
1 150mm-length 1/8-inch brass
threaded rod
4 brass nuts to suit
1 22mm aluminium knob
2 12mm brass untapped spacers
2 9mm brass untapped spacers
2 6mm brass untapped spacers
4 1/8-inch steel washers
1 4-way AA square battery
holder
1 battery clip for holder
4 AA alkaline cells
4 6 x 60mm diameter rubber
bands
1 SPDT toggle switch
3 ORP12 or equivalent LDRs
(LDR1 -LDR3)
2 10kQ horizontal trimpot
Semiconductors
2 LM339 quad comparators
(IC1 ,IC2)
2 BD646 PNP Darlington
transistors (01 ,02)
1 3.3V 1W zener diode (ZD1)
2 1N4002 1A diodes (D1 ,D2)
2 1N4148 switching diodes
(D3,D4)
1 5mm red LED (LED1)
Capacitors
1 470µF 16VW PC electrolytic
1 100µF 16VW PC electrolytic
2 10µF 16VW PC electrolytic
3 2.2µF 16VW PC electrolytjc
1 0.1 µF MKT polyester
Resistors (0.25W, 1%)
1 68kQ
1 22kQ
6 10kQ
11.2kQ
11 1kQ
1 390Q
1 180Q
1 47Q
Miscellaneous
Solde·r, tinned copper wire.
referred to earlier. This device is wired
as a Schmitt trigger oscillator by virtue of the 68kQ feedback resistor conn·ected between pins 1 & 7. It oscillates by the following action.
FEBRUARY
1993
17
+6V - - - - - - - - - - - ,
+3.3V - - - - - - - - - - 111 SPEED
VR1 10k
10k
+3.3V
V+
2
1k
13
LDR1
LEFT
ORP12
03
1N4148
1k
2.2 +
111
BACK EIIF
1k
16VWi
+UV
1k
68k
1.2k
10k
LDR2
CENTRE
ORP12
1
.,.
J7.J
10k
BCE
.,.
22k
v'v
2.2 +
16VW+
+6V
+3.3V - - - - - - - - - - - V+
112 SPEED
VR2 10k
+3.3V
14
1k
04
1N4148
LDR3
RIGHT
ORP12
1k
.,.
1k
2.2 +
10 +
16VW+
16VW+
112
BACK EIIF
1k
.,.
.,.
.,.
POWER
l°
...
S 1-;.:_:.,._
:
_ _ _ _ _+---\'147'1J:lr-6V_
-
T
6V:
+
__,.,.__
__,.,.___
+3.3V
1800
V+
ZD1
3.3V
1W
100 +
J
.,.
···1
ELECTRONIC COCKROACH
Fig.2: IClb, I Cl a & Ql drive motor Ml on one side of the vehicle, while IC2b,
IC2c & Q2 drive motor M2 on the other. Normally, Ml is controlled by IClb
which compares the back-EMF with a triangle waveform generated by IC2a.
When IClb's output switches high, pin 1 ofICla goes low & turns on Ql to pulse
the motor. However, ifless light falls on LDRl than on LDR2, pin 13 ofIClc
switches low & the motor turns off. LDR3, ICld, IC2b & IC2c control M2 in
exactly the same manner.
18
SILICON CHIP
When power is first applied, the
2.2µF capacitor on pin 6 has no charge
and so the output at pin 1 is high. The
2.2µF capacitor now charges via the
22kQ resistor until the voltage at pin
6 exceeds the voltage on pin 7. When
that happens, pin 1 switches low and
the 2.2µF capacitor discharges via the
22kQ resistor until the voltage on pin
6 drops below the voltage on pin 7
again. Pin 1 of IC2a now switches
high again and so the cycle is repeated indefinitely for as long as
power is applied.
Thus, the 2.2µF timing capacitor is
alternately charged and discharged via
the 22kQ resistor and the resulting
output is a triangle waveform as
shown in Fig.1. This waveform has an
amplitude of about 200mV (1.541. 76V) and a frequency of about 66Hz.
This triangular waveform is applied
to the non-inverting inputs of comparators ICla, IClb, IC2b & IC2c.
IClb compares the triangle waveform with the voltage on its pin 4
(inverting) input, as set by trimpot
VRl and the back-EMF developed by
the motor (Ml). This voltage sets the
duty cycle of the voltage pulses that
appear on IClb's pin 2 output, as
shown in Fig, 1.
The voltage pulses from IClb are
next inverted by comparator stage
IC la. This stage uses the triangle waveform at its non-inverting input (pin 7)
as a voltage reference. The voltage
pulses from IClb swing between DV
and 3.3V, whereas the triangle waveform varies between 1.54V and 1.76V.
Thus, when the output ofIClb swings
low, pin 1 of ICla is pulled high and
vice versa.
Note that the output of ICla is
pulled high to +6V (via a lOkQ resistor), despite the fact that the supply
rail to the IC is less than this figure.
This is possible because of the open
collector output and ensures that PNP
transistor Ql fully turns off when pin
1 is pulled high.
When pin 1 of ICla swings low, Ql
is turned on via a lkQ current-limiting resistor. This transistor is a
Darlington type (BD646) with a minimum DC gain of 750. Thus, we only
require a small amount of base current to ensure that the transistor is
fully turned on (ie, saturated) when
driving the motor.
Dl protects Ql by quenching any
large spikes that are generated by the
motor when the transistor turns off.
Fig.3: install
the parts on
the PC board
as shown in
this wiring
diagram. The
three LDRs
should all be
mounted at full
lead length (see
text) .
D3 and its associated components
make up the back-EMF monitoring
circuit. Note that because we only
want to sample the back-EMF developed across the motor, this sampling
process must take place when Ql turns
off.
When Ql is off, the back-EMF developed by the motor is sampled by a
voltage divider consisting of two lkQ
resistors. D3 will be forward biased
during this time and so a sample of
the back-EMF also appears across the
10µF filter capacitor. This voltage is
further filtered by a lkQ resistor and a
2.2µF capacitor and then applied to
pin 4 of IC1b.
Thus, if the back-EMF rises, the
voltage on pin 4 ofIClb also rises, the
output pulses from IC1b narrow, and
the motor slows down. Conversely, if
the back-EMF falls, the voltage on pin
4 falls and so the output pulses
lengthen to bring the motor back up to
speed. VR1 adjusts the initial voltage
level on pin 4 and thus sets the overall speed of the motor.
When Ql turns on, D3 is reverse
biased and thus the voltage previously
developed across the 1DµF filter capacitor does not change.
The second motor, M2, is controlled in exactly the same manner by
ICZb, ICZc and Darlington transistor
Q2. The back-EMF of this motor is
monitored via diode D4, while VR2
sets the overall speed of the motor.
LDR control
From the foregoing, it might seem
that the two motors run continuously
but that is not the case. Instead, one or
both motors can be switched off, depending on the light falling on the
three LDRs (LDR1 , LDR2 & LDR3).
LDR2 monitors the ambient light
level and, in company with its associated 1.ZkQ resistor, sets the voltage at
the non-inverting inputs of comparators IC1c and IC1d (pins 11 & 9). If the
light level goes down, the resistance
of the LDR increases and the voltage
on pins 11 & 9 also increases.
In the case of motor Ml, comparator IC1c monitors the voltage across
LDR1 and compares this with the voltage across LDR2. If less light falls on
LDR1 than on LDRZ, the voltage on
pin 10 ofIClc will be greater than that
on pin 11. As a result, IC1c's output
(pin 13) switches low and pin 1 of
IC1a goes high.
This turns Ql and motor Ml off
and so the vehicle turns towards LDR1
(assuming that MZ is running).
Conversely, if more light falls on
LDR1 than on LDR2, IC1c's output
effectively goes open circuit and so
has no effect on IC1a. IC1b thus supplies a PWM waveform to IC1a as
described before and so Ml runs at
normal speed.
LDR3 controls motor MZ in exactly
the same manner. If less light falls on
LDR3 than on LDR2, motor M2
switches off and so the vehicle steers
in the opposite direction.
Note that a 1.2kQ resistor is used in
series with LDR2, while lkQ resistors
are used in series with LDR1 and
LDR3. This arrangement ensures that
both motors switch off if there is equal
light on all three LDRs. So, when the
Electronic Cockroach crawls into a
dark corner, it automatically switches
its motors off to conserve the batteries.
Power supply
Fig.4: each motor shaft is fitted
with a 10mm length of brass
tubing as shown in this diagram.
A solder mound is then added to
the tubing so that the rubber
band stays on the shaft.
Power for the circuit is derived from
a 6V battery pack consisting of four
AA cells. Sl switches the power on or
off, while LED 1 lights when the power
is on.
The 6V rail directly powers the
Darlington transistors (Ql & QZ), while
the ICs are powered via a decoupling
circuit consisting of a 180Q resistor
and a 470µF capacitor. This decoupling network filters out any supply rail ripple that's caused by the
heavy current drawn by the motors.
Finally, a regulated 3.3V rail is derived using zener diode ZD1 and a
1D0µF capacitor. This regulated rail
FEBRUARY
1993
19
MOTOR
SHAFT-
Fig.5: this plan view
shows how the motor
shafts are coupled to
the front wheels via
the rubber bands.
Position the axle so
that Jhe rubber bands
stretch by about 7mm
when they are
installed & adjust the
spacers so that the
wheels clear the PC
board by 2mm.
MOTOR
-SHAFT
RUBBER
BAND-
UNDERSIDE OF PC BO ARD
12mm UNTAPPED BRASS
SPACERS SOLDERED
6mm UNTAPPED
BRASS SPACERS
/
WHEEL
RUBBER
- BAND
WASHERS
TO PC BOAR~D_\
_ _ _~,-"'-t
I
- - - -----------1
\
ADJUST FOR RUBBER
BAND TENSION
1/8" BRASS
TUBING
WHEEL
I
'\
CRIMP END
WITH
PLIERS
2mm j
130mm
supplies the LDR networks and provides the bias for ICl b and IC2b.
Construction
A PC board coded 08310921 (207 x
83mm) accommodates all the parts see Fig.3.
Before installing any of the parts ,
check the holes sizes for the motor
mounts and th e rear wheel pivot. The
motor mounts should be drilled to
3mm while a 5mm hole will be required to accept the 9mm-long spacer
that pivots the rear wheel. This spacer
should be soldered into place so that
it protrudes about 3mm above the
board surface (see Fig.6).
Follow the overlay diagram care-
fully when installing the parts on the
PC board and don't forget the eight
wire links (note: the prototype differs
slightly from Fig.3). Make sure that
the semiconductors and electrolytic
capacitors are all oriented correctly.
The two Darlington transistors are
mounted with their metal tabs towards
the motors.
The three LDRs should all be
mounted at full lead length. Adjust
LDR1 and LDR3 so that they face sideways, as shown in the accompanying
photograph. LDRZ should be adjusted
so that it faces towards the floor.
The two motors can now b e
mounted in position using 2.5mm
machine screws and nuts and their
leads soldered to the PC board. Note
that the red wire of motor 1 runs to
Dl's cathode, while the red wire of
motor 2 runs to D2's anode. This is
necessary because the motors must
run in opposite directions to each
other.
The circuit can now be checked for
correct operation. Wind both trim pots
fully clockwise, then switch on and
check for +5V (approx.) on pin 3 of
each IC. ZD1 should have a nominal
3.3V across it.
Now place some insulation tape
over LDR2 and rotate one of the trimpots until its corresponding motor
begins to run. When it does, do the
same for the other motor. Adjust the
RESISTOR COLOUR CODES
0
0
0
0
0
0
0
0
0
20
No.
1
1
6
11
1
1
1
SILICON CHIP
Value
68k.Q
22k.Q
10k.Q
1.2k.Q
1kn
390.Q
180.Q
47.Q
4-Band Code (1%)
blue grey orange brown
red red orange brown·
brown black orange brown
brown red red brown
brown black red brown
orange white brown brown
brown grey brown brown
yellow purple black brown
5-Band Code (1%)
blue grey_ black red brown
red red black red brown
brown black black red brown
brown red black brown brown
brown black black brown brown
orange white black black brown
brown grey black black brown
yellow purple black gold brown
motors for slow running and check that each
motor exhibits quite a lot of torque when you
try to stop it by grabbing hold of its shaft. If it
does, then the back-EMF feedback control is
working correctly.
Finally, check that each motor stops when
you cover its corresponding LDR with your
finger. The motor should immediately restart
when you remove your finger, If all is OK,
switch off and move on to the mechanical assembly. If it doesn't work, go over the board
carefully and check for wiring errors.
NUT
E
,§
..,
9mm UNTAPPED BRASS SPACER
SOLDERED IN HOLE IN PCB
..,____ WASHER
"NUT
\
118' THREADED BRASS ROD
22mm DIA
ALUMINIUM
KNOB
Mechanical assembly
The first step in the mechanical assembly is
to fit a 10mm length of 1/8-inch diameter brass
tubing over each motor shaft. To do this, cut two
10mm lengths of tubing with a hacksaw and file
the ends smooth. This done, crimp each piece
lightly at both ends using side cutters, then
push them onto the motor shafts (see Fig.4) .
To keep the rubber bands running true, a
convex mound of solder is applied to the centre
of each shaft. This ensures that the rubber bands
remain on the shafts and don't wind off when
the motors start to run. If the belt begins to
wander off centre, it will quickly restore itself.
To form this convex mound, run the motor at
slow speed by shorting out its LDR, apply the
iron and allow the solder to slowly build up on
the shaft. When a sufficient mound. has built
up , remove the iron and allow the solder to cool
with the motor still running.
Warning: if the motor is allowed to run too
fast during this procedure, you may end up
with molten solder flying off the shaft. As a
r,.<,.~ ' - - 9mm BRASS
SPACER
60mm
DRILL HOLE THROUGH
KNOB THIS END
I
Fig.6: the rear wheel assembly is made up using a 22mm-diameter
aluminium knob, a 150mm-length of threaded brass rod, two 9mm
spacers & several nuts & washers. Make sure that the knob spins
freely on its spacer & that the pivot assembly operates correctly
before soldering the nuts to the threaded rod.
Below: the arrangement of the front & rear wheel assemblies can be
gauged from this "under-the-chassis" view. Note that a small piece
of black cloth was glued to the rear wheel (ie, to the aluminium
knob) so that its appearance matched that of the other wheels.
~
FEBRUARY
1993
21
precaution, we strongly recommend that you wear safety
goggles to prevent possible eye injury.
Once the solder has cooled, it can be further shaped
using a small file. Again, this is best done with the motor
running slowly.
Wheel assembly
The first step in the front wheel assembly is to find the
correct location for the axle. To do this, temporarily fit
one of the wheels to the axle, position it on the underside
of the PC board, and install the rubber band as shown in
Fig.5. Now position the axle so that the rubber band
stretches slightly (5-8mm should be about right) and
mark the position of the axle on the board with a pencil.
The axle runs inside two 12mm spacers which are
soldered to the underside of the PC board, with additional free-running 6mm spacers fitted to ensure that the
inside edges of the wheels just clear the PC board. Fig. 5
shows the details.
Initially, the two 12mm spacers should be lightly tack
soldered into position. This done, test the assembly by
fitting the axle, 6mm spacers and wheels. Adjust the
lateral position of the 12mm spacers to provide the
correct amount of wheel clearance from the board (about
2mm), then complete the solder joints.
The wheels can now be permanently installed by cutting the axle to length and crimping the axle ends with
pliers as shown in Fig.5. Note that two small washers are
fitted between each wheel and the crimped axle end to
ensure that the wheel turns freely.
Don't just use one washer here. If you do, it may bind
on the crimped end of the axle and make the wheel
difficult to turn.
The pivoting rear wheel assembly is shown in Fig.6.
On the prototype, this wheel was made from an aluminium knob. The normal shaft hole was drilled right
through the knob to accept a 1/8-inch threaded brass rod,
. while a 9mm brass spacer serves as the wheel bush. This
brass spacer is simply fitted into the existing 6mmdiameter shaft hole in the knob.
The wheel assembly is fitted to one end of the brass rod
and secured with a nut on either side. Make sure that the
wheel turns freely but without too much play before
permanently soldering the nuts in position.
This done, bend the rod into a U-shape around the
wheel as shown in Fig.6, taking care to ensure that the
rod finishes up at right angles to the axle. The end of the
rod is then bent upwards through 90° about 60mm from
the axle, so that it fits through the vertical spacer soldered to the PC board.
Secure the wheel assembly to the vertical spacer using
nuts and washers as shown in Fig.6.
The battery holder can be secured to the PC board
using two rubber bands (the same size as those used to
drive the motors). To improve their appearance, we dyed
the rubber bands black using normal fabric dye (just
follow the hot pan dying procedure outlined on the
packet).
In normal operation, LDR2 should face down towards
the floor for best results. If you find that the car only runs
when LDR2 is covered, increase the value of the 1.2kQ
resistor to 1.5kQ
Finally, you can easily modify the circuit so that the
22
SILICON CHIP
0
0
0
0
T"'"4
(\J
CJ'
0
T"'"4
M
CD
0
u
Cl)
Fig.7: here is the full-size pattern for the PC board (code
08310921). Check your board carefully to ensure there
are no etching defects before installing any of the parts.
vehicle turns away from the dark rather than towards it.
This is achieved simply by connecting motor Ml to
motor M2 's pads on the PC board and vice versa. The
lead polarities must also be swapped over, so that the
motors continue to run in the correct direction.
SC
When we in 1989 decided to design Australia's finest range of loudspeakers, we soon realised the potential we had on our hands.
By designing and building the speakers in Australia, and by using the ultimate drivers available, we could challenge the best
loudspeakers from around the world. With this in mind we now set out to achieve our go~.
The choice of drivers was obvious: DYNAUDIO. They are known the world over as being the finest drivers
available. The high cost however, makes their use prohibitive for those speaker manufacturers who only
produce mass market speakers. Our intention though, was not to make another mass market
range of loudspeakers, but rather Australia's finest.
The next step was to appoint a design team. The ideal team should have not only the
best technical qualifications and facilities, but also a great love and appreciatic;m
for music.
With the design team chosen, work began in February
1990. Now followed an exhaustive but rewarding 14 months
of intensive research and development. Numerous prototypes were built
and refined until each model fulfilled its objectives: Being the finest in its class.
The listening panel comprised not only the design team, but also Hi-Fi critics and leading
audio dealers from around the country. Each prototype was compared against the more expensive
imported equivalents until the design team was fully satisfied.
In June 1991 Australia's finest range of loudspeakers was released : DYNAUDIO IMAGE.
WE HAVE DONE All WE CAN ..... NOW IT'S UP TO YOU !
Acknowledgements:
Acoustical Design: Glen Leembrugen & David Connor, Sydney Australia
Dynaudio Drivers: Mark Thorup & Peter Larsen, Skanderborg Denmark
Solen Capacitors: Dennis Quellet, Quebec Canada
Bi-wiring Terminals: Ben Fan, Taipei Taiwan
Monster Cable:
Noel Lee, San Fransisco USA
Cabinet Builder: Scott Krix, Hackham South Australia
Listening Panel:
Glen Leembruggen, David Connor, Pat Hayes, Les Cardilini ,
Philippe Luder, Dahl Murphy, Carlo Di Martino , Craig McNeil,
Michael Henriksen, David Jacobs, Tom Manning
For more information and name of nearest dealer please contact:
&an Audio Pty. Ltd., P.O. Box 242, Hawthorn Vic 3122
Ph. (03) 429 2199
Fax (03) 429 9309
CIRCUIT NOTEBOOK
Interesting circuit ideas which we have checked but not built and tested. Contributions from
readers are welcome and will be paid for at standard rates;
H:RNtES ~ 0 . 2 2
CIRCUITRY
HANDS FREE
SPEAKER
+12V
COURTESY
LIGHTS
10k
1M
DOOR ~
SWITCHESr
4.7k
10k
-:-
Horn blower for
mobile telephones
They say that necessity is the mother
of invention and that certainly applies to this circuit.
My brother is a plumber and has a
new mobile phone and an associated
hands-free set for his van. Naturally,
he doesn't want to expose his expensive new phone to the hazards of wa-
Square wave
frequency doubler
Using just one 4011 quad NAND
gate IC, this circuit accepts a squarewave signal and doubles its frequency.
ICla and IC1b are connected as
inverters, with IClb driven by the
output ofICla. Both gates also drive
separate single-pole RC filters, each
filter consisting of a .001µF capacitor and a 6.8kQ resistor.
When a square-wave signal is
applied to the input, the outputs of
ICla and IClb are out of phase.
When the inputs ofIC1a or IC1b go
24
SILICON CHIP
-:-
ter, sand and dust on building sites.
This simple circuit plugs into the
hand-free circuit and blows the horn
whenever the phone rings, thus allowing him to leave the phone in the
safety of the van.
The "trigger" signal for the circuit
is picked up from the "hot" side of the
hands-free loudspeaker via a 0.22µF
capacitor. Thus, when the phone rings,
the resulting voltage pulses charge a
2.ZµF capacitor via D3 and a couple
of series resistors. DZ clips any large
negative-going spikes, while D4
clamps any large positive-going spikes
to the +12V supply rail.
Comparator stage ICla (LM339)
compares the voltage developed across
the 2.ZµF capacitor with a reference
voltage on its non-inverting input (pin
5). This reference voltage is set by
VR1 which basically functions as a
sensitivity control. When the voltage
on pin 4 exceeds the reference voltage
(ie, when the phone rings), -pin 2 of
ICla switches low and turns on Ql
and relay RLY1 to sound the horn.
To prevent the circuit from operating when the van is being driven (ie,
. . . . - - - - - - - - - - - - - - - +3-15V
high, the resulting output low
·causes a negative-going spike to appear at pins 8 & 9 of IClc. This gate
converts these spikes into output
pulses at pin 10 and these pulses
occur on each edge of the input
signal to ICla (ie; one pulse on the
rising edge and one on the falling
edge). So we end up getting two
pulses for each input pulse.
The· width of the output pulses
is a function of the RC time constants at the outputs of IC1a and
IC1b. The period of the input frequency must be greater than twice
these RC time constants.
Darren Yates,
SILICON CHIP.
when the ignition is on), comparator
IC1b pulls pin 4 of IC1a low and thus
turns off Q1 and the relay. When the
ignition is off, pin 1 of IC1b is open
circuit and the circuit operates normally.
Another problem is that hands-free
speech can also trigger the circuit.
This problem was solved by using
one of the door switches to shunt the
input signal to earth via D1 when the
door is open. This means that handsfree conversations must be made with
the door open when the vehicle is
parked but this is the normal situation for my brother anyway.
Alternatively, you can use a switch
to shunt the trigger signal if you wish
to converse with the doors shut. The
duration of the horn blasts can be
adjusted using sensitivity control VR1.
Glen Host,
Doubleview, WA. ($35)
Simple way to make
PC boards
This idea might seem silly but it
actually works. If you are fortunate
enough to have a PC and CAD software that will print a circuit board
layout on your laser printer, then you
have all that is needed for instant
circuit boards.
Once you have prepared your design on the computer, print it on the
laser printer as you normally would.
There are a few things to note though.
First, you have to print it" actual size"
(1:1) and second, it has to print "wrong
reading" (component side).
Take a blank piece of copper clad
board, thoroughly cleaned, and lay
the printed copy on it face down.
Using moderate pressure and an ordinary domestic clothes iron set to "cotton" (see, we told you it was silly),
iron the paper on to the copper. Be
careful not to move the paper as you
go. After a few seconds the toner will
stick to the copper. It seems to be best
to keep the heat on until the fibreglass
board itself is hot as well.
Leave the board with the paper attached to cool for a minute and then
place it in warm water and allow it to
soak for a few more minutes. You can
then carefully remove the paper, leaving the toner firmly adhered to the
copper surface. Any pieces of paper
left behind can be carefully rubbed
off with your finger. The toner makes
an excellent resist and the board is
Robotics interface
for PCs
This interface circuit was designed to operate a crane made out
of Swiss Meccano directly from
the PC under the control of a
GWBASIC program. There are eight
motors powering the crane so eight
of the interface circuits shown here
must be used.
Each of these data lines is connected to an optoisolator (OPT1).
When the output line goes high,
the internal LED lights and turns
on the internal phototransistor.
This turns on transistor Q1 which
energises the relay coil and turns
on the appropriate motor.
Resistor R3 limits the current
through the base of Q1, which is
protected against negative voltage
spikes by diode Dl.
The accompanying program
shows how each relay can be
switched on individually.
P. Dumuid,
Adgate, SA. ($25)
----------------o+SV
PC
PRINTER
PORT
DB25
D2-D9
C1 +
220
16VW-
R1
1k
OPT1
4N28
A.
R4
150D
LED1
RED
5V RELAY
NEC
MR62-5a
PC GND 2
':'
R2
2.2k
~'"{
ONE OF EIGHT
10 KEY OFF: CLS
20 NOS$=" FIRST":GOSUB 50: H=I: NOS$=" SECOND": GOSUB 50: G=I: NOS$="
THIRD": GOSUB 50: F=I
30 NOS$=" FOURTH": GOSUB 50: E=I: NOS$=" FIFTH": GOSUB 50: D=I: NOS$="
SIXTH": GOSUB 50: C=I
40 NOS$=" SEVENTH": GOSUB 50: B=I: NOS$=" EIGHTH": GOSUB 50: A=I: GOSUB 90:
CLEAR: GOTO 10
50 LOCATE 1,1: PRINT"WHAT OUTPUT DO YOU WANT TO GO TO THE ";NOS$;:INPUT
"OUTPUT(1/0)";I
60 LOCATE 1,1: PRINT"
70 RETURN
80 END
90 OU=O
100 PRINT "A=";A;:IF A= 1 THEN OU=OU+ 128: PRINT" 128" ELSE PRINT""
110 PRINT "B=";B;:IF B = 1 THEN 0U=OU+64: PRINT" 64' ELSE PRINT" O'
120 PRINT "C=";C;:IF C = 1 THEN 0U=OU+32: PRINT" 32" ELSE PRINT" O'
130 PRINT "D=";D;:IF D = 1 THEN OU=OU+ 16: PRINT" 16' ELSE PRINT" O'
140 PRINT "E=";E;:IF E = 1 THEN 0U=OU+8: PRINT" 8' ELSE PRINT" O'
150 PRINT "F=";F;:IF F = 1 THEN 0U=OU+4: PRINT" 4" ELSE PRINT" O'
160 PRINT "G=";G;:IF G = 1 THEN 0U=OU+2: PRINT" 2' ELSE PRINT" O'
170 PRINT "H=";H;:IF H = 1 THEN OU=OU+ 1: PRINT" 1" ELSE PRINT" O'
180 OUT &H0378,0U: PRINT" ";OU
190 INPUT DUMMY$
200 RETURN
now ready to etch in the normal way.
Naturally, this method is not perfect. If you design a board with tracks
0.1mm thick spaced 0.2mm apart, then
you can't expect good results. But if
you can avoid using fine tracks or
running tracks too close·together, then
it is far more accurate than using the
felt pen method. You can also experiment with different paper stock. I
found that "Matt Art" achieves the
best results.
Glen Andersson,
Ashfield, NSW. ($15)
FEBRUARY
1993
25
SIMPLE PROJECTS FOR
MODEL RAILROADS
Most model railroad layouts are
fairly basic but by spending just a few
dollars and a little time with a soldering iron, you can make your layout far
more realistic and interesting. These
three circuits are easy to build and
can be added to virtually any model
railroad layout.
1. Train Controller
Our first circuit is for a Low-Cost
Model Train Controller with simulated inertia - see Fig.1. Many model
railroad sets come with a simple rheostat controller but these give poor lowspeed running characteristics. They
also give rise to jack rabbit starts and a
model that slows or even stalls on
curves and gradients.
Unlike a rheostat controller, the circuit of Fig.1 behaves as a constant
voltage source at any given throttle
setting and this gives much improved
control at low running speeds. In particular, starting is much smoother and
the model no longer stalls or slows
when the going gets a little tough. Of
course, a pulse power controller gives
even better control but is much more
expensive than the controller described here.
As a bonus, our low-cost controller
26
SILICON CHIP
These three low
cost projects will
enhance the
appeal of any
model railroad
layout. They
include a low-cost
train controller, a
traffic lights
simulator & a
points controller.
By TERRY MOWLES
provides simulated inertia and braking. This is just a fancy way of saying
that the train adjusts its speed gradually when you vary the throttle and
slows gradually when the brakes are
applied, just like a real train. A couple of preset pots allow you to adjust
the amount of inertia to suit your layout.
How it works
Fig.1 shows the circuit details. It's
basically a beefed-up version of the
controller published in the November
1990 issue. The original circuit could
supply up to 1.2A whereas this new
version can supply up to 3A. This is
useful if you want to multiple-head
locos, particularly if they have smoke
generators, lighting and sound generators.
Power is derived from a 3A 12V AC
source (eg, via a mains transformer)
and this is rectified by diodes D1-D4
to provide about 17V DC. Alternatively, the bridge rectifier can ,be bypassed and the unit operated from a
12-18V DC source. This voltage is then
tapped off by throttle control VRl and
applied to the base ofQl via Sla, D5,
VR2 and a series 5.6kQ resistor.
Ql and Q2 form a Darlington output stage and this is forward biased as
soon as the voltage on Ql 's base
reaches 1.3V. Q2 then conducts and
supplies voltage to the track via a
0.22n 5W resistor. Double pole switch
B
12-18VAC
05
1N4007
SPEED
VR1
5k
0
INERTIA
VR2
1k
EOc
VIEWED FROM
BELOW
0
PLASTIC
SIDE
m
BRAKE
S1a
0
B
A~K
ECB
47 +
25VW_
S1b
+
4700
25VW-
FORWARD
S2a
4700
REVERSE
BRAKE LEVEL
VR3
1k
FORWARD
S2b
TO
TRACK
REVERSE
LOW COST 3A TRAIN CONTROLLER
Fig,1: the circuit uses Ql & Q2 to buffer the output of throttle control VRl. Q3 provides overload
protection by reducing the drive to Ql when the voltage across the 0.22Q resistor reaches 0.65V.
S2 provides forward/reverse switching by swapping the supply polarity
to the track.
Q3, LED 1 and the 0.22Q resistor
provide overload protection. Normally, the voltage across the 0.220
resistor is less than 0.65V and Q3 has
no affect on the circuit operation.
When a short circuit occurs, the output current shoots up until there is
about 0.65V across the 0.220 resistor.
Q3 then turns on and reduces the
drive to Ql, thus limiting the output
current to about 3A. LED 1 indicates
that an overload has occurred.
VR2 and its associated 4700µF capacitor provide simulated inertia for
the throttle. This inertia effect occurs
TO TRACK
a~
S1
s2[
~
~
because it takes t1me for the capacitor
to charge or discharge to its new level
each time the throttle is varied. D5
prevents the 4700µF capacitor from
discharging through VR1 when the
throttle setting is reduced.
VR3 and the 4700µF capacitor provide the braking inertia. When braking switch Slb is closed, Sla opens
and the 4700µF capacitor discharges
via the 4700 resistor and VR3. This
gradually reduces the voltage on the
base of Ql so that the train slows to a
stop. When the brake is subsequently
released, the train builds up speed to
its previous setting (assuming that VR1
is not touched in the meantime).
Note that it is not necessary to reFig.2: wire up the Thain
Controller as shown in
this diagram, The circuit
shows the pin connections
for transistors Ql, Q2 &
Q3. Note that Q2 should
be fitted to a large finned
heatsink for cooling.
duce the throttle to zero before applying the brakes. That's because Sla
switches the throttle out of circuit
when braking is applied.
Building the controller
Fig.2 shows the wiring details for
the controller. Mount the parts on the
TRAIN CONTROLLER
PARTS LIST
1 PC board, 106 x 48mm
1 5kO linear potentiometer (VR1)
2 1kO PC-mounting trimpots
(VR2,VR3)
2 DPDT miniature toggle
switches (S1 ,S2)
1 finned heatsink (see text)
1 TO-3 mounting kit (mica washer
plus insulating bushes)
Semiconductors
1 BD139 NPN transistor (Q1)
1 2N3055 NPN transistor (Q2)
1 BC337 NPN transistor (Q3)
4 1N5404 silicon diodes (D1-D4)
2 1N4007 silicon diodes (D5,D6)
1 red ~ED (LED 1)
Capacitors
1 4700µF 25VW PC electrolytic
1 47µF 25VW PC electrolytic
Resistors (0.25W, 5%)
1 5.6kO
1 4700
10.2205W
FEBRUARY
1993
27
It's also possible to bolt the transistor directly to the heatsink, provided
that you make sure that the heatsink
does not touch any other component.
That's because the heatsink will now
float at the full supply voltage if there
is no isolation.
2. Traffic Light Simulator
The Train Controller PC board can be hidden under the layout, while the
controls can be mounted in a small plastic case to give a walkaround throttle
or they can be mounted on the main console.
If you intend operating the unit from
a DC source, install D1-D4 anyway so
that the supply can be connected with
either polarity. The 5W resistor should
be mounted about 5mm proud of the
T03
-....;;;:::.;;;;:;~;:::;::;:;;::::;;:~ DEVICE
board, so that the air can circulate
beneath it to provide additional coolMICA
ing. We mounted the LED directly on
~WASHER
the board but it could also be mounted
~
elsewhere (eg, on a control panel) and
C
connected by flying leads.
C>
C>
HEATSINK
C
Be sure to install the LED with the
correct polarity, otherwise the overload protection circuitry won't work
~ INSULATING
~ BUSHES
(its anode lead is the longer of the
two). Use medium-duty hook-up wire
tfltJ-R<at>
for the connections to the power supS~~~EA~
ply, track and switch S2, since these
<at>
<at>w~m~s
leads carry currents up to 3A. The
remainder of the wiring (ie, to the
©>
LED, Sl and VR1) can be run using
<at>NUTS
rainbow cable or light-duty hook-up
Fig.3: here are the mounting details
wire.
for Q2. It should be isolated from the
Finally, power transistor Q2 must
heatsink using a mica washer &
be mounted on a large finned heatinsulating bushes.
sink, since it dissipates quite a lot of
power. Fig.3 shows the mounting dePC board exactly as shown, taking . tails. Note that the transistor is electricare to ensure that all polarised parts · cally isolated from the heatsink using
are correctly oriented. In particular,
a mica washer and two insulating
note that the metal face of the BD139 bushes. Smear all mating surfaces with
(Ql) faces towards the 4700µF capaci- heatsink compound before bolting the
assembly together.
tor.
e
s~::~:~iF
28
SILICON CHIP
Fig.4 shows the circuit for the Thaffic Light Simulator. This was first published in SILICON CHIP in November
1989. It drives green, red and yellow
LEDs to accurately simulate traffic
light cycles at an intersection.
555 timer IC1 is wired as an astable
oscillator and this provides a clock
signal for IC2, a 4017 decade counter.
IC2 's 0-9 outputs go high in turn on
each successive clock signal and drive
several sets of OR gates made up by
diodes D1-D20. These OR gates then
drive transistors Q1-Q6 to control the
traffic light LEDs (LEDs 1-12).
Note that each transistor drives two
LEDs of the same colour, one for each
opposing light set.
When pin 3, pin 2 or pin 4 of IC2 is
high, Ql turns on and lights LEDs 1 &
2 (green) for one set of lights. Q4 will
also be turned on during this time
TRAFFIC LIGHTS
PARTS LIST
1 PC board, 92 x 78mm
9 PC stakes
Semiconductors
1 555 timer (IC1)
1 4017 decade counter (IC2)
1 7805 3-terminal regu lator
(REG1)
6 BC548 NPN transistors (0106)
4 green LEDs (LED1 ,2, 11, 12)
4 yellow LEDs (LED3,4,9, 10)
4 red LEDs (LED5,6,7,8)
20 1N914 silicon diodes (D1 D20)
1 1N4007 silicon diode (D21 )
Capacitors
1 220µF 25VW PC electrolytic
1 100µF 16VW PC electrolytic
2 10µF 16VW PC electrolytic
1 0.1µF metallised polyester
Resistors (0.25W, 5%)
6 100kO
6 4700
1 82kO
1 2200
1 4.7kO
1 1500
100k
~
~
16
~
~
D4
1N914
1
2 4
7
Vk
s
~
IC2
4017
D5
10
4
5 1
6 5
14
82k
7 6
9
IC1
555
11
13
~
~
10 +
~
D17
1N914
16VW+
+9V
D21
1N4007
+12V
100 +
2200
16VW+
LED7-8
GREEN
LED9·10
YELLOW
1500
~
B
ROC
VIEWED FROM
BELOW
~ Jt
100k
100k
~
~
~
~
~
I G0
TRAFFIC LIGHT SIMULATOR
Fig.4: the Traffic Light Simulator uses 555 timer IC1 to clock
decade counter IC2. This device then drives the traffic light
LEDs via transistors Q1-Q6 & a number of OR gates formed
by diodes D1-D20. Fig.5 (right) shows how the parts are
installed on the PC board. Each output driv~s tw,p LEDs of
the same colour, one for each opposing set of lights.
HIGH12J
(via an OR gate consisting ofD11-D16) and this turns on
the two red LEDs for the other set of lights.
The other diode OR gates ensure that the remaining
LEDs for each set of lights turn on and turn off in the
correct sequence as the 4017 counts up. For example,
when pin 7 is high, Q2 and Q4 are on and this lights
LEDs 3-4 (yellow) and LEDs 7-8 (red) . As with real traffic
lights, there is a brief period of time when both sets of
lights are red (ie, pin 10 or pin 11 high).
Each complete cycle takes about 25 seconds and is
then repeated. The timing period can be altered by
.changing the timing components in the oscillator (ICl) .
Power for the circuit can come from any +12V DC
source and this is applied to REGl to derive a regulated
+9V rail. Diode D21 protects the circuit against reverse
supply polarity.
Finally, a lOµF capacitor and 4. 7kn resistor are used
FEBRUARY
1993
29
Protect your valuable issues
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These beautifully-made binders
will protect your copies of SILICON
CHIP. They feature heavy-board
covers & are made from a
distinctive 2-tone green vinyl.
They hold up to 14 issues & will
look great on your bookshelf.
* High quality
* Hold up to 14 issues
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* SILICON CHIP logo printed in
gold-coloured lettering on spine &
cover
Price: $A 11 .95 plus $3 p&p each
(NZ $6 p&p). Send your order to:
Silicon Chip Publications
PO Box 139
Collaroy Beach 2097
Or fax (02) 979 6503; or ring (02)
979 5644 & quote your credit card
number.
Use this handy form
l
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$._ _ _ or please debit my
□
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Address_ _ _ _ _ _ _ _ __
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., _ _ _ _ _ _ _ _ _ _ _ ,1
30
SILICON CHIP
This is the finished Traffic Light Simulator board. Take care with component
orientation & note that diode D21 is a 1N4007 type. The remaining diodes are
all 1N914 types & are installed with their cathodes towards transistors Q1-Q6.
to provide a power-on reset signal for
ICZ. This is necessary to ensure that
the 4017 starts reliably each time
power is applied to the circuit.
capacitor's charge is dumped via DZ
into one of the two solenoids that are
used to control the points (one to open
them and one to close them). During
Construction
Fig.5 shows the PC board parts layout for the traffic light simulator. You
can install the parts in any order but
take care with component orientation.
The outputs that drive the LEDs are
all marked on the PC board. Note that
each output drives two LEDs of the
same colour, one for each opposing
set of lights. The LED anodes are all
connected together and wired to the
+9V output on the PC board.
3. Points Controller
The final circuit is the Points Controller - see Fig.6. It can be powered
from any 12-15V AC or DC source. Dl
half-wave rectifies the incoming voltage in the case of an AC supply, or
provides reverse polarity protection
in the case of a DC supply.
When power is applied, Ql conducts and quickly charges the 2200µF
capacitor. At the same time, LED 1
lights to indicate that the circuit is
ready. The points can now be opened
or closed by pushing one of momentary-contact pushbutton switches (either S1 or S2).
As soon as S1 or S2 is pushed, the
There is room on the Points Controller
PC board for a second 2200µF
discharge capacitor, should this prove
necessary to operate the solenoids.
POINTS CONTROLLER
PARTS LIST
1 PC board, 54 x 36mm
1 TIP41 C NPN transistor (01)
3 1N4007 silicon diodes
1 red LED (LED1)
1 2200µF PC electrolytic
1 2.2kQ 0.25W resistor
1 3900 0.25W resistor
Why pay $1000's
for
encyclopedias?
If you own a computer with a CD drive,
then you can own the 22 vol NEW 1991
Grolier Electronic Encyclopedia for
$160. Let the computer do the
scanning!
LQQK
PARENTS
SQNy;
Computer
Requirements
either,
1) IBM PC. PS2 or compatible, 512K.
MSDOS 3.0, VGA card & Monitor CD
ROM Drive
OR
2) Apple Macintosh with CD Rom
Drive.
LQQK
PARENTS
CD\ROM & SOFTWARE
~ s:
~
II MIXED-UP
MOTHER GOOSE*
SONY LASER LIBRARY
FAMILY.
II COMPTON'S
ENCYCLOPEDIA
'
•
Ill LANGUAGES OF
Iii THE WORLD
Translates to and from Chinese, Danish, English,
Finnish, French, German, Italian, Japanese,
Norwegian, Spanish & Swedish. Translations can
be exported directly to WP packages (Chinese
and Japanese display only). Includes the full text
of 18 dictionaries in 12 languages. - equivalent
to 132 dictionaries!
COMPUTER REQUIREMENTS (for package)
XT/AT Compatible, 512k Ram. DOS 3.1
Hard disc drive - half size slot
Recommended:
VGA Monitor & VGA adapter
Mouse
* Requires VGA
TITLE
POPULAR CD ROMS
DESCRIPTION -
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Encyclopedias:
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Just Grandma and Me
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Languages of the World
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Mixed up Mother Goose
National Geographies Mammals
Night Owl Shareware Ver. 6
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32,000 articles, 1500 illustrations including sound
and speech recording. Forget flipping through
volumes, instead, follow key pathways on words
and subjects - access information in the blink of
an eye.
$860
l!I NATIONAL GEOGRAPHIC
Ill SOCIETY'S MAMMALS*
Not only Is this Software
•
Educational - It's fun too!
Not only can this fantastic software package
educate you and your children, it also can
provide hours of entertainment. Info on 200
animals, photos, range maps, motion clips,
essays and 155 animal vocalizations .
II
WORLD ATLAS*
--
The World Atlas brings the entire globe to your
computer screen. This atlas, almanac and world
fact book in one, gives you instant access to over
240 fully detailed, EGA/VGA colour maps and a
huge database of international information.
PACKAGE CONTENTS
Sony internal drive CDU 535 which supports
CD Rom mode 1 & 2 & Audio
Value $540 (one year warranty)
Sony bus interface card (half card value $180)
Software - 6 CD's as detailed - Value $998
Microsoft CD - Rom Extensions
SPECIAL OFFER
-
all for IBM (also Mac where shown) ORDER PRICE
Chess with sound and animation
D
$90
Microsofts musical journey (also MAC)
D
$135
9 Bibles 3000 Sermons, 6 dictionaries
D
$90
Classic story - music and sound effects
D
$90
A classic game - now a classic CD
D
$90
-
see above
as above plus animated sequences
see above - (also MAC)
Invaluable Information, 1500 Q & A's - (also MAC)
USDA's database, nutrients, calories- analyse foods
Games - inc Chessmaster, Bruce Lee, Black Hole
Games - inc Loopz, Puzzle Gallery, Robot Tank
Tour London, New York, Sydney and 7 others
Tour Berlin, Chicago, Rome, and 7 others
Multimedia - the best seller plus pictures and sound
A living book - childrens' interactive fun
A classic game - now a classic CD
See above
Windows version - see above
see above
see above
600MB of IBM compatible code, 10,000 programs
Nursing literature from Medline 1962-89
Text and Images on horticulture. weeds, etc
DTP Program incl, WP, 69 fonts, 1000 clips
Consulting Detective - interactive game
Interactive Fairytale - adventure game
Timelines with sound and animation (also MAC)
Clip art, animations, games, digitized music
Deluxe version of the bestseller
The best seller in•compact format
Popular game plus Secret Missions 1 & 2
Popular game plus Ultima V1
see above - (also MAC)
D
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$159
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I'll MICROSOFT
•
1M BOOKSHELF 1991
.,
·
. _-
This indispensable collection of reference
materials includes the American Heritage
Dictionary, Roget's II Electronic Thesaurus, the
World Almanac and Book of Facts, Barlett's
Familiar Quotations, and more. For added
efficiency, all reference volumes interface directly
with more popular word processing programs.
CDU 535 DRIVE SPECS
5¼" Half-Height Internal
340ms avg. access time
150KB sustained data transfer rate
600KB burst data transfer rate
8KB buffer
Output jacks for stereo and head phones
r - MAILTH,scouPONroDAv- , I
I
(Allow 14 days for delivery)
I
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enclose cheqoe, money order for$.....................
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See ue II Booth 141, HOME COMPUTER SHOW, Melbourne
I
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.J
D1
1N4007
12-15V
AC OR
DC
Q1
TIP41C
Fig.6 (left): the Points Controller uses the discharge qirrent from a
2200µF capacitor to control the points solenoids. This capacitor is
charged via Ql when power is applied. The capacitor discharges
& Ql turns off each time one of the pushbutton switches is press_
e d.
Fig.7 (below) shows the parts layout on the PC board.
~ J
---------e--o
BCE
$1
E
D2
1N4007
~
TO POINTS
SOLENOIDS
----------e--o
+
GND
12-15V AC
OR DC
+V TO 51
AND 52
GND
2200
25VW_
LED1
GNDo-------------t------oGND
POINTS CONTROLLER
this time, DZ also pulls Ql's base below its emitter and so Ql is turned
off. This ensures that the points solenoid only receives a brief current pulse
from the charged capacitor and prevents it from burning out if the button
is held down for too long.
The ZZ00µF capacitor charges via
Dl and Ql again as soon as the pushbutton switch is released. D3 protects
Ql against any large negative-going
spikes that are generated when the
solenoid turns on.
By the way, you can use this circuit
to control as many sets of points as
you wish - just wire in additional
m,omentary contact pushbutton switches to control their solenoids.
Construction
Assemble the parts on the PC board
as shown in Fig. 7, making sure that
Where to buy the kits
Kits for these projects are available from T. A. Mowles, PO Box 491, Noarlunga
Centre, South Australia, 5168; or from Force Electronics stores in Adelaide,
South Australia. The prices are as follows:
(1 ). Train Controller (does not include heatsink or TO-3 mounting kit) .. $27.95
(2). Traffic Light Simulator (includes 12 miniature LEDs) ..... .......... ....... $22.95
(3). Points Controller (does not include switches) ..... .. ....... ....... .. ..... ....... $9.95
Payment should be made by cheque or money order. Please add $3.50 for p&p
or $5 for 2-5 kits.
Note: copyright of the PC board patterns is retained by T. A. Mowles.
all polarised parts are correctly oriented. Note that some points solenoids may require more current than
can be delivered from a single ZZ00µF
capacitor. For this reason, there's space
on the board for a second capacitor if
required.
No heatsink is required for the
TIP41C since it only dissipates a few
milliwatts. If the LED brightness is
insufficient, reduce the value of the
series 2.ZkQ current limiting resistor.
In some cases, it may be necessary to
come down to 1.ZkQ.
SC
RESISTOR COLOUR CODES
No.
TRAIN CONTROLLER
0
0
0
0
1
1
1
Value
4-Band Code (5%)
5-Band Code (1%)
5.6kQ
470Q
0.22Q
green blue red gold
yellow violet brown gold
not applicable
green blue black brown brown
yellow violet black black brown
not applicable
100kQ
82kQ
4.7kQ
470Q
220Q
150Q
brown black yellow gold
grey red orange gold
yellow violet red gold
yellow violet brown gold
red red brown gold
brown green brown gold
brown black black orange brown
grey red black red brown
yellow violet black brown brown
yellow violet black black brown
red red black black brown
brown green black black brown
2.2kQ
390Q
red red red gold
orange white brown gold
red red black brown brown
orange white black black brown
TRAFFIC LIGHTS SIMULATOR
0
0
0
0
0
0
6
1
1
6
1
1
POINTS CONTROLLER
0
0
32
1
1
SILICON CHIP
SILICON CHIP
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Card No.
FEBRUARY
1993
37
Ever run out of petrol? This simple
project reminds you to fill 'er up
by lighting a 12V lamp when_
the fuel drops below a preset
level.
A low fuel
indicator for your car
By JOHN CLARKE & GREG SWAIN
OST LATE-MODEL cars have a
low-fuel warning light but any
vehicle that's more than about
five years old probably lacks this important feature. This means that you
have to remember to check the fuel
gauge regularly to avoid runn~ng out
of petrol
Well that's the general theory but if
you drive a "gas-guzzler", it's all too
M
easy to get caught. Result - an empty
tank and you're left stranded. Often,
this is only inconvenient but running
out of petrol can also be dangerous.
That's why late-model cars have a
low-fuel warning lamp. It's easy to
neglect a gauge but a carefully positioned warning lamp ("idiot" light?)
is much more visible and consequently harder to ignore.
The Low Fuel Indicator described
here is easy to build and can be installed in most vehicles. It lights a
12V warning lamp when the fuel in
the petrol tank drops below a preset
level. If you've ever run out of petrol
or have come close to doing so, this
project is well worth building. It could
save you quite a few dollars , not to
mention embarrassment and inconvenience.
Types of sensors
Apart from the lamp, there are just three external wiring connections from the
Low Fuel Indicator: to +12V via the ignition switch, to vehicle chassis & to the
fuel sensor lead. The warning lamp lights when the critical point is reached.
38
SILICON CHIP
In most cars, the fuel sensor consists of a float-controlled rheostat
which is wired in series with the fuel
gauge - see Fig, 1. These two components are then connected to a regulated supply rail derived from the battery. As the fuel level varies, the resistance of the rheostat also varies
and this in turn controls the current
through the fuel gauge (ie, the fuel
gauge acts as a milliammeter).
Usually, the higher the float level,
the lower the resistance of the rheostat and the higher the current through
the fuel gauge. Some circuits work in
the reverse sense to this though, so
our clrcuit has been designed to accommodate both situations. All you
have to do is change the location of a
single wire link.
B_e warned, however, that this circuit is not suitable for cars that have
capacitance-type fuel sensors. In this
type of sensor, the fuel acts as a dielectric between two parallel plates
PETROL TANK
METER
SENDER
r---------,
+V FROM
IGNITION
''
I ______
":'
L
_ ___ JI
which form a capacitor. As far as we
know, only the Ford Falcon (model
XD onwards) uses this type of sensor
but you should still check to ensure
your car has a rheostat sensor before
starting this project.
How it works
Let's now take a look at the circuit
of the Low Fuel Indicator - see Fig.2.
It works by monitoring the voltage
across the rheostat in the fuel sensor.
In greater detail, the voltage from
the fuel sensor is first filtered by a
47kQ input resistor and a ZZ0µF electrolytic capacitor which combine to
provide a 10-second response time.
This 10s delay is built in to prevent
false triggering near the preset level
due to fuel sloshing about in the tank.
IC1a, an LM339 comparator, compares the filtered sensor voltage on its
pin 8 input with a reference voltage
on pin 9. This reference voltage is
derived from a regulated 9.1 V rail via
a lOkQ resistor and trimpot VR1. It is
fed via another lOkn resistor to pin 9
of IC la, to pin 7 of IC1 b and to pin 4 of
IC1c.
Note that because the LM339 has
PARTS LIST
Fig.1: in most cars, the fuel
level sensor consists of a
float-controlled rheostat.
This controls the current
through a meter which then
indicates the fuel level.
1 PC board, code 05203931, 61
x46mm
1 12V panel mount indicator
lamp
1 10kQ horizontal trimpot (VR1)
5 PC stakes
1 3mm machine screw and nut
open collector outputs, pin 14 ofIC1a
is fitted with an external 10kQ pullup resistor. Thus, depending on the
fuel level, pin 14 ofICla will be either
high or low. The lMQ feedback resistor provides the stage with a degree of
hysteresis, so that it switches cleanly
at the transition point and eliminates
lamp flicker.
ICla drives comparator stages IClb
and IClc. One of these stages then
drives Darlington transistor Ql, depending on whether link LKl or link
LKZ is installed. If the fuel sensor
voltage increases with decreasing fuel
level, LKl is installed and Ql is controlled by IClb. Conversely, if the sensor voltage falls with decreasing fuel
level, LKZ is installed and Ql is controlled by IClc.
Let's assume initially that the sensor voltage rises with decreasing fuel
level (ie, LKl must be installed). Thus,
when the tank is full , the sensor voltage will be low and pin 14 ofICla will
be high (ie, at +9.lV). Pin 1 of IClb
will thus be low and so Ql and the
warning lamp will both be off.
As the fuel level falls, the voltage
on pin 8 of ICla steadily increases.
+V FROM
I G N I T I O N D - - - - - - - - - - - - - - - - - - - - - - - ---<11--- - - - .
SWITCH
ZD1
9.IV
1W
100 +
18VW+
10k
1M
10k
.,.
FROM FUEL
SENSOR
2.2k
FUEL
LEVEL
SET
VRI 10k
47k
220 +
18VW+
47k
CHASSIS~
12V
LAMP
SW MAX
Semiconductors
1 LM339 quad comparator (IC1)
1 BO679 NPN Darlington
transistor (01)
1 9.1 V 1W zener diode (ZD1)
Capacitors
1 220µF 16VW PC electrolytic
1 100µF 16VW PG electrolytic
Resistors (0.25W 1%)
1 1Mn
2 47kn
310kW
1 2.2kn
1 150!1
1 10Q 5W
Miscellaneous
Automotive hook-up wire,
automotive connectors.
When the fuel drops below the preset
level, pin 14 ofICla switches low and
pin 1 of1C1b is pulled high by a z.zkn
pull-up resistor. This high turns on
Ql and lights the warning lamp. The
lamp then remains lit until the fuel
tank is filled above the preset level (or
until the ignition is switched off).
Now let's consider the circuit action where the sensor voltage falls
Fig.2: the circuit uses IC1a to
compare the voltage from the fuel
sensor with a reference voltage
set by VR1. When the fuel in the
tank drops below the critical
level, pin 14 ofIC1a changes
state. This then switches on Q1 &
the lamp, either via IC1b & LK1
or via IC1c & LK2.
Q1
B0879
.,.
.,.
PLASTIC
SIDE
rn
E
B
C
LOW FUEL INDICATOR
.,.
FEBRUARY
1993
39
FROM F
SENSO
0
c.n
ro
CHAS
0
w
....w
'°
Fig.3: install LKl if the sensor voltage rises as the
fuel level drops. Alternatively, install LK2 if the
sensor voltage falls with decreasing fuel level.
Fig.4: check your PC board for defects against
this full size etching pattern before mounting
any of the parts.
with decreasing fuel level (ie, LKZ
05203931 and measures 61 x 46mm.
must be installed). In this case, pin 14
Fig.3 shows the assembly details.
of IC la is normally low and thus pin 2 Before starting construction, you first
of IClc is also low.
have to test the sensor to discover
If the fuel level now drops below whether link LKl or link LKZ should
the preset level, pin 14 switches high be installed. To do this, locate the
and so pin 2 of IClc is pulled high by gauge terminal that connects to the
the 2.ZkQ pull-up resistor. This then fuel sensor and short it to chassis via
turns on Ql via link LKZ and lights a l0Q 5W resistor with the ignition
the lamp as before.
on. If the fuel gauge reading goes up,
The level at which the circuit trig- . install LKl. Conversely, if the reading
gers is set by adjusting VRl. Normally, goes down, install LKZ.
this would be set so that the lamp
The remaining parts can be installed
comes on just before the fuel gauge in any order but make sure that ICl,
ZDl and the two electrolytic capacineedle dips into the red danger zone.
Power for the circuit is derived from tors are correctly oriented. We used
the car's battery via the ignition PC stakes at the five external wiring
switch. This +12V (nominal) supply points but these can be considered
powers the indicator lamp directly to
optional.
ensure maximum brightness when Ql
Ql should be mounted flat against
turns on.
the PC board with its plastic side facZDl and its parallel lO0µF filter ing upwards. Bend its leads at rightcapacitor provide the regulated 9.1 V angles so that they pass through the
supply rail. This supplies ICl and the holes in the PC board before securing
voltage divider for the reference volt- it using a screw and nut. Trim away
age, and ensures that the circuit is any excess lead lengths after solderunaffected by fluctuations in the bat- ing.
tery voltage. ZDl also protects ICl by
clipping any voltage spikes that may Installation
Because the PC board is so small, it
be generated by the electrical system.
can be easily wrapped in foam insulaConstruction
tion and hidden under the dashboard.
All the parts for the Low Fuel Indi- The warning lamp can be mounted
cator (except the lamp) are mounted directly on the dashboard and conon a small PC board. This is coded nected to the PC board via flying leads.
Alternatively, the board could be fitted inside a small plastic case, along
with the warning lamp, and the entire
assembly then mounted on top of the
dashboard.
The remaining connections are to
+12V via the ignition switch, to chassis, and to the fuel sensor lead. If you
have trouble identifying the sensor
lead, check the colour code in the
manual or check the lead at the fuel
sensor.
Use automotive connectors to interface to the vehicle wiring and solder the other ends of the leads to the
PC stakes on the circuit board.
Calibration
The best way to calibrate the unit is
to wait until the fuel gauge reaches
the critical level and then adjust VRl
so that the device just triggers. This
critical level will normally be just
above the red zone.
If want to calibrate the unit immediately, disconnect the fuel sensor lead
at the gauge and connect a lO0Q
potentiometer between the gauge and
chassis. Adjust this potentiometer until the gauge indicates the desired critical fuel level, then adjust VRl on the
PC board until the lamp just comes
on.
That's it. Now there's no excuse for
ever running out of petrol.
SC
RESISTOR COLOUR CODES
0
0
0
0
0
0
40
No.
Value
_4-Band Code (1%)
5-Band Code (1%)
1
2
1MQ
47kQ
10kQ
2.2kQ
150Q
brown black green brown
yellow violet orange brown
brown black orange brown
red red red brown
brown green brown brown
brown black black yellow brown
yellow violet black red brown
brown black black red brown
red red black brown brown
brown green black black brown
3
1
1
SILICON CHIP
PIUJdeect 'if:~ 'Reteaae
1te«,,
1:] ·:•:1trn:,if:i:ti: : : :rs1.ttsua:1: s:m:rre:m:<at>:i:e:11::1$;:11it:::· ]11e:1<:ttm:ei11te:s)t:1ama:: : :1
t 1:1:te::s:s.:a1:1;e :s i: :::1
IPOFFERING
•
EXTRA SIZES
11
MORE ACCESSORIES
LOWER PRICES
■
NATURAL or BLACK
ANODISED FRAMES
•
FOREST GREY or
BLACK TEXTURE
COVER FINISHES
READER INFO NO. 6
THE UNIQUE ZIP-RACK DESIGN
SIMPLE, FAST & EFFECTIVE THATS ZIP-RACK
Twelve lengths of ZIP-RACK hollow section aluminium extrusion are interconnected using black ABS plastic corner
connectors. This requires only a rubber mallet or similar tool. The assembly is self aligning and can be further strengthened
by 'pop' riviting the overlapping flanges at each corner.
TYPE 46 RACK DATA:
RACK WIDTH 540mm. RACK DEPTH 460mm. 1U (RACK UNIT) =44.45mm OR 1 3/4".
FOR EQUIPMENT/PANEL CAPACITY DEDUCT 90mm FROM TOTAL RACK HEIGHT
COVER SET
IDENT NO.
GREY
J:it.ie.k: ;
:1
:•:•:•:•.•.•:•.•:•.•.•:•:•:::::::•:•::,::
F04
F06
F09
P.R!dl!M
TOTAL
RACK
HEIGHT
t: i ::;
C04
C06
C09
268
357
490
F12
F15
F18
624
757
890
F24
F30
F40
1157
1424
1868
ACCESORIES
6/01
t
PRICE$
M6 PACK
12 M6 Clip Nuts~
2 M6 Ph. Screws
12 Nyl Washers
6/01BK
6/02
6/03
6/03BK
6/04
6/04BK
As 6/01 in Black
100 M6 Clip Nuts
100 M6 Screws
100 M6 Screws Black
100 M6 Washers
100 M6 Washers Black
CT2
CT3
CT4
Cantilever Tray 2U
Cantilever Tray 3U
Cantilever Tray 4U
ZIP-RACK is made by "The ZIP-RACK Company" Factory 2, 7 Michellan Court, Bayswater Victoria 3153. Australia.
Under licence to AUTOTRON AUSTRALIA P/L. The ZIP-RACK Designers
Beware of illegitimate copies without the ZIP-RACK name. For product sales, wholesale pricing & product literature
Phone:
{03) 729 7255
or Fax:
{03) 729 6017
COMPUTER BITS
BY DARREN VATES
File back..ups plus a useful utility
program for LHA & PKZIP
Making back-ups at the end of the working day
need not be the chore it seems. With a little
programming, you can get your computer to do
most of the hard work for you.
For many people, the days of backing up their hard disc on a regular
basis are all but over. For example,
just imagine what's involved in backing up even 80Mb of hard disc space
onto floppy discs. For starters, you'd
need around 70 1.2Mb floppy disc
plus a couple of zillion years sitting
in front of the screen waiting for the
prompt that tells you when to install
memory as possible and then copy
them all over in one hit.
But what about files that are too big
to fit on a single floppy disc? This is
now a common problem, especially if
you are working with a CAD program,
an accounting or spreadsheet package, or page layout software (particularly if scanned images are involved).
Of course, you can back up onto mul-
The two best known file compression utilities
are PKZIP and LHA. Both are capable of
compressing files to a fraction of their
original size - often 20% or less, depending
on the file.
the next disc into the drive.
But what about the work files you
create on a daily basis? Obviously,
these need to be backed up at regular
intervals to protect against hard disc
crashes and executive wrath!
Copy&Xcopy
So what does DOS have to offer in
this regard? DOS has two commands,
COPY and XCOPY, for copying files
but XCOPY is the more efficient. If
you decide to copy a complete directory to a floppy disc, COPY will copy
the files across one at a time whereas
XCOPY will load as many files into
42
SILICON CHIP
tiple floppy discs using the BACKUP
command, but the best answer is often to use some form of file compression.
File compression is also handy if
you are running out of hard disc space.
Little used files can be compressed to
a fraction of their original size and the
original file deleted. When the file is
required again, you simply run it
through the reverse part of the compression program. This process is generally called "un-zipping" or "extracting" and it gives you the original file,
ready for use.
It's worth noting that compression
programs are not just limited to data
or ASCII files. They can be used on
other files as well, including .EXE,
.COM and binary files. In fact, many
computer programs are now supplied
with compressed files. When the program is installed, the files are automatically unzipped.
LHA&PKZIP
The two best known file compression utilities are PKZIP and LHA. Both
are capable of compressing files to a
fraction of their original size - often
20% or less, depending on the file.
However, PKZIP. requires a separate
program, PKUNZIP, to restore compressed files to their original condition.
By contrast, LHA uses a software
switch in the command line to enable
it to do both jobs. That said, there's
little to choose between the two programs in terms of user convenience,
at least for everyday file compression
and extraction.
So how do they work? Without going into the details, both programs
use a series of mathematical algorithms to perform file compression.
In either case, it's best to store the
program in a utilities directory on
your hard disc. This directory should
be inserted in the PATH command in
your AUTOEXEC.BAT file. That way,
the compression program can be run
from any directory or subdirectory on
the disc.
Neither utility is a terminate-stayresident (TSR) program, so you won't
run into problems if you're running
Windows with limited memory.
To create an archive using LHA,
you type the following command:
Iha a <compfile> <file.ext>
where "compfile" is the name you
wish to give to the compressed file
and "file.ext" is the file that you wish
to compress. The "a" switch tells LHA
to add the file to an archive (note:
earlier versions of the program require
you to type "lharc a ... ).
When finished, the compressed file
will have a ".lzh" extension; ie, a file
called compfile.lzh will be created.
Note that this is an extra file; the
original file (file.ext) remains unaltered on the disc.
Alternatively, LHA can also compress and add a file to an existing
archive. And it will work with wildcard characters. For example, the command:
Iha a <compfile> <* .exe>
will compress and add all files with
the extension ".exe" to an archive
called "compfile.lzh".
Having added files to an archive,
you can list them using the "l" switch
or extract then using the "e" switch.
For example, to list all files in an
archive called "compfile.lzh", you
type:
Iha 1 <compfile>
Note that there is no need to add
the ".lzh" extension to the file name,
as LHA automatically assumes this
extension.
Similarly, to extract a file called
file.exe, you type:
Iha e <compfile> diie.exe>
To use PKZIP, you type:
PKZIP <compfile> <file.ext>
As before, "compfile" is the name
of the archive and "file.ext" is the file
that you wish to compress. Note that
PKZIP gives the archive a ".zip " extension; ie, it creates a file called
"compfile.zip".
Not to be outdone by LHA, PKZIP
also accepts wildcard commands. For
example, the command
PKZIP <compfile> <*. *>
will compress and add all files in the
directory to compfile.lzh. The corresponding command for LHA is
Iha a <compfile> <*. *>
Zipping up automatically
Although LHA and PKZIP are great
for backing up and storing compressed
files, they do have their limitations.
For example, let's say that you
wanted to compress 10 large files and
back them up onto a floppy disc. Neither program has any problem in automatically compressing all these files
into a single archive but what hap-
pens if the archive is greater than
1.2Mb (or 1.44Mb)? There's no way
you can copy the archive to floppy
discs and back again unless you use
the cumbersome BACKUP and RESTORE commands.
Unfortunately, neither program can
take all 10 files and automatically zip
them up into separate archives. Of
course, you could sit there and type
LHA a <filename> <filename.ext> for
each file but after you've typed the
first few entries, you quickly get sick
of it.
What's needed is a utility program
that will enable LHA or PKZIP to automatically do this for you. By zipping
each file up individually, you can then
use the Windows File Manager (or
another file manager) to select blocks
of compressed files (up to 1.2Mb or
1.44Mb) for copying to a floppy disc.
Compress.exe
As the saying goes, "many an invention has come about through necessity" and that goes triple for computer programs! To solve this inherent problem with LHA and PKZIP,
we've come up with a small utility
program using QuickBasic 4.5.
This utility program is called "Compress.exe" and it will automatically
create a separate compressed copy of
each file in a specified directory (using either LHA or PKZIP) and store it
in that same directory. Of course, it
also leaves the original copy of the
file in the directory as well.
The program works like this: when
you run the program (you just type
<compress>), a subroutine asks for
the name of the directory that contains the files you wish to have compressed.
And that's about it from your side
of things. The program takes over from
here. If you make a mistake and you
wish to get rid of the compressed files,
go to the DOS prompt in that directory and just type <erase * .lzh> or
<erase * .zip> as appropriate.
Things to check
When using this program, it's important that the first part of each
filename be different to every other
one in that directory. If they're not,
files with the same prefix are compressed into a single archive.
If the files are only small, this may
not be a bad thing in some cases but it
is something you need to be aware of.
No files are lost if this occurs - compression programs are smart enough
to extract all files.
The best part about both LHA and
PKZIP\PKUNZIP is that they are
"shareware" and can be downloaded
from many bulletin boards. For example, both programs are available on
the Dick Smith Electronics bulletin
board. This operates as a 24-hour service and you can use a modem with
anything up to 14,400 baud. There are
two lines for the BBS: (02) 887 1146
and (02) 887 2276.
Obtaining Compress.exe
In a future issue, we'll take a more
detailed look at both LHA and PKZIP
and check out what other options they
have to offer. In the meantime, to obtain a copy of "Compress.exe", just
send us a formatted floppy disc plus
$5 to cover the cost of return postage.
Don't forget to specify whether you
have LHA or PKZIP, so that we can
send you the correct version of the
program. The program will work on
all PC-compatible machines running
DOS 4.01 or later.
SC
VIDEO & T.V.
SERVICE PERSONNEL
TV & VIDEO FAULT LIBRARIES
AVAILABLE AS PRINTED MANUALS $85 +P/H
BOTH MANUALS T.V. & VIDEO $145 +P/H
• OR AS A PROGRAM FOR IBM COMPATIBLES OR AS AN
.
APPLICATION PROGRAM FORD-BASE 111 PLUS
FOR MORE INFO. CONTACT TECHNICAL APPLICATIONS
PO BOX 137 KENMORE 4069 OR FAX/PHONE (07) 3781064
FEBRUARY
1993
43
VERY LARGE LCD
DISPLAY MODULE
SODIUM VAPOUR
LAMPS
111
Brand new large 640 x 200
dot matrix LCD displays,
made by EPSON - SEIKO,
screen size is 120 x 265mm,
has built in drivers. Four bit
TTL interface, a total of 14
connections are required for
signal arid power (+5V, -12V).
Capable of displaying
characters, graphs, patterns
etc. 28 pages of information
included. ON SPECIAL for
two months
:•:::::,;,~\"1!::»f~S'::;"::!%~;,.'::i~\"<;:~.···
A very small but complete IR
tele- scope which only needs
an EHT power supply, which
is provided in kit form.
$279
Item No. 0121 A
Includes a "Free" 75mm IR
filter.
Based on an IC with 20dB of
gain, a bandwidth of 2Ghz
and a noise figure of 2,8db
this amplifier kit out performs
many other IC's, and is a
fraction of their cost. The
complete kit of parts for the
masthead amplifier PCB and
components, and the power
and signal combiner PCB and
components, is priced at an
incredible:
$tS
(Item No. 0166)
Note th;;.1 an LSI surface
mount controller IC for this
display is available. This IC
has a built in character set
generator and many other
features. It is compatible with
8080 and 6800 MPU's. The
IC is available elsewhere for
about $35, and we will supply
more information upon
request.
NEW 12 CHANNEL
UHF REMOTE
CONTROL
Brand new 6 volt 1 watt
amorphous solar panels. Two
of these in series make a
great 12V battery maintainer/
charger. Incredible pricing.
$10eafor 10 for $85.
Fore more information see a
novel , extremely popular, and
an effective active antenna
design which employs this
amplifier: MIRACLE TV
ANTENNA - E.A. May _1992.
LASER GUN SIGHT
Item No. 0130
MARINE
SEARCHLIGHTS
A SmW gunsight at an
unbeatable price.
$279
Coming soon is our new 12
channel UHF remote control
channel that is easily
expandable to 16 channels.
The system features a SAW
resonator locked transmitter,
prealigned and assembled
receiver "front end" which
solders onto the main
receiver PCB, and a very
compact 2 channel relay
driver PCB which can be
used in multiples: Up to eight
units. As a price indicator, we
will be offering a package
deal consisting of
2 transmitter kits, plus one
receiver kit, plus three relay
driver kit$, for a total cost of
$200
12V OPERATED
LASER BARGAIN
. ..
.. ,,,, ..,.. ,.
Item No. 0108
Includes one "Free" rifle or
pistol mount.
STEPPER MOTORS
$25
,...-• · - ··
· ,. ' impressive unique, product
with many applications.
Two used 3mW Siemens HeApproximate weight of pillar
Ne visible red laser tubes,
and Spotlight is 60KG.
and one of our efficient 12V
universal laser supply kits.
(Ref:XXFEB93101)
$129
The $6 P+P charge doesn't
apply to this one!! "Ring"
Item No. 00105X
$1100
Brand new units. Diameter
,S8mm, height 25mm, 5V
operation , simple to drive
(Two phase - 6 wires), 7.5
egree steps , coil resistance
6.6 ohm:
$12 Item No. 0140.
Driver IC 9UCN5804B) plus
circuit $9.
DISTANCE
MEASURING
WHEEL
This brand new instrument
consists of a large wheel
attached to a handle bar, with
two separate mechanical
counters. Used for measuring
distances: 50mm resolution,
10KM counter. Quality U.K.
made instrument at about 1/3
of it's real value. Two only at:
$270Ea.
(RtifXXFEB93102)
Ea.
(Ref: XXFEB93103)
SOLAR LIGHTNING
BARGAIN
long ... $5.50
M4 - 3-15V, I No load= 20mA
at 12V, main body 31 mm
Diam - 22mm long ... $3
M5-3-15V, I No load= 60mA 5700 RPM at 12V, main body
28mm Diam - 40mm
(E.A. NOV. 92) This kit has
three separate sections that
long ... $2.50
are contained on one PCB,
M9-12V, I No load= 0.52Abut can be separated:
15,800 RPM at 12V, main
(1) A crystal locked ultrasonic ·body 36mm Diam - 67mm
movement detector, (2) A
long ... $8.50
fluorescent tube inverter
M 14 - Made for slot cars, 4(4-20W) with logic circuitry,
8V, I No load= 0.84A at 6V,
(3) A solar battery charging
at max efficiency I = 5. 7 A regulator, and an incalescent
7500 RPM, main body 30mm
lamp switcher - pulser, which
Diam - 57mm long... $9.50
employs a mosfet switch, as a Further to the above special
package special we are
prices, during Feb.:March w.:
offering the complete kit for
are offering an introductory
the three sections plus six
package which includes ONE
6V/1 W solar panels for a tot~I OF EACH OF THE ABOVE
cost of:
MOTORS, and one of the
STEPPER MOTORS
advertised elsewhere in ttlis
(REF: XXFEB93104)
ad. (Item No. 0140) .
ONLY $99!
ULTRASONIC
BURGLAR ALARM
KIT
See S.C. May 88 for this high
quality crystal locked
ultrasonic design. Can be
used as a detector or a self
standing alarm, has provision
for bonnet/boot protection and
flashing light and back up
battery. Easily combined with
our U.H.F. Remote Control.
CLEARANCE PRICED AT
ONLY:
These new 0.5 metre
diameter military grade
search li!Jhts were made by
LUCAS in the U.K. They are
painted grey and are almost
totally made of brass, except
for a few stainless steel
screws and nuts, a mirrored
glass parabolic reflector, and
a glass cover plate, They
have a detachable mounting
pillar which brings the total
height of the searchlight and
the stand to approximately 2
meters. Fully adjustable
positioning and focussing.
Supplied with a 1000W/240V
Mt:i.~;€\?$?::ffZ?!t€tsfr:1 ~~~o~zo ~~~~~~- l~~~~T1 1).
$109
Brand new 140W low
pressure sodium vapour low
pressure lamps. Overall
lenght 520mm, 65mm diam.,
G.E.C. type SO1 /H. We
supply data for a very similar
lamp (135W). LIMITED
QUANTITY.
D.C. MOTORS
We have good stocks of 5
different high quality
JAPANESE DC Motors.
These should suit many
industrial, hobby, robotics and
other applications. Check out
the SPECIAL prices, and
compare!
M1 - 24V, I No load= 50mA 22,000 RPM at 24V, main
body 28mm Diam - 40mm
$29.90
(Cat. No. GK125)
For the P.C.B. and all parts,
except the screw terminals.
A pair of ultrasonic
transducers is included!!
DON'T MISS OUT!
SIX DIFFERENT MOTORS
FOR A TOTAL COST OF
$30.
Main body has a diameter of
117mm and is 107mm long.
The whole assembly can be
easily unscrewed to obtain
three very large lenses: two
plastic and one glass. The
basis of the cheapest large
magnifier or projection
system? Experimenters
delight at
ONLY $28
MYSTERY LASER
Includes 1 12VMK3 universal
power supply kit, plus a used
laser tube with a power rating
in the 1-3mW range. A laser
tube and a power supply for a
little more than the price of
the inverter only:
$89
(Item No. 0110)
VISIBLE LASER
DIODE KIT
Brand new 5mW-670nM laser
diode, plus a collimating lens,
plus driver kit, plus, hardware,
plus instructions.
$89
Item No. 0164
Used air cooled ARGON laser
heads, that produce a BLUE
beam! Power output is in the
30-100mW range. Limited
stock, at a fraction of their
$600-800 ...
real value:
For the Argon head only. We
also provide a circuit for a
simple power supply.
Item No. 0109
TUNING FORK
FILTER PCB's
t 1'/~ 1
INDUCTIVE
~~~Jc
/
Each one of these identical
PCB filter assemblies
contains six three terminal
tuning fork filters (IN-GNDOUT), at different frequencies
in the audio range: 1.8-3.1
Khz.
These high quality dual fork
filters have very narrow
bandwidths, and could be
used as the basis of a
selective call system, high
stability oscillators etc.
LED DISPLAYS
IR FILTER
LCD DISPLAYS
1 1
...
~- J
_J___
These industrial quality
detectors will detect ferrous
and non-ferrous metals at
close proximity. Some are
" DC
powered (10-30VO, some are
AC powered (Mains) , am;t all
will switch loads directly. All
have a three wire for connecting into circuitry: Two for the
supply, and one for switching
the load. LIMITED
QUANTITIES at a small
fraction of their real price:
$28
EHT GENERATOR
KIT ' \\
These are new 16 character
by 2 hne alphanumeric LCD
display modules , with surface
mount control circu itry
mounted on the rear of the
display. Require a few
milliamperes at 5V to operate,
information included:
$18
5
$80
ea . or
for
(Item No. 0131)
OFFER.
CRAZY BATTERY
Brand new industrial grade
PANASONIC 12V/6.5AH
sealed gel batteries at a
•educed price. Yes 6.5
AMPERE HOURS! Use them
in lighting, ala[ms ,
communications, laser power
supplies, solar systems etc.
Dimensions: 100 x 94 x
65mm. Weight of one battery
is 2.2KG! The SPECIAL
PRICE?
ea.
(Ref.XXFEB93101)
Furthermore, here is the
CRAZY OFFER. Buy three of
these batteries at the above
price, and we .will deliver them
to any mail addresses in
Australia at no additional
costs!! YES $114 TOTAL
COST, TO HAVE THREE OF
THESE BATTERIES
DELIVERED TO YOUR
DOOR!!
We also have available a
suitable overnight charger for
these batteries
(500mA) ... $25ea. No
additional delivery charge
applies if the charger/s is/are
bought with the above three
battery offer.
,.
Small PCB Assembly based
on a ULN2232IC.
This device has a built in light
detector, filters , timer, narrow
angle lens, and even a siren
driver circu it that can drive an
external speaker. Will detect
humans crossing a narrow
corridor at distances up to 3
metres. Much higher ranges
are possible if the detector is
· illuminated by a remote
visible or IR light source. Can
be used at very low light
levels , and even in total
darkness. With IR LED. Full
information provided . The IC
only, is worth $16! OUR
PRICE FOR THE
AS~~BLYIS:
:ji(j EA, OR 5 FOR $25
Item No. 0163
IIR LASERS
A high quality military grade
deep infra red (IR) filter. Used
to filter the IR spectrum from
medium and high power
incandescent spotlights and
flood lights. It's glass base
makes it capable of
withstanding high
temperatures. Approx. 130m
diameter and 6mm thick. Can
be used in conjunction infra
red night viewers and IR
responsive CCD cameras:
Many colour video cameras
and most monochrome video
cameras have good IR
response: Check by viewing
the LED's in an TV or VCR
infra red remote control.
Excellent for night
surveillance equipment! At a
FRACTION OF THEIR REAL
PRICE .
ON SPECIAL AT ONLY:
$38
NATIONAL
SEMICONDUCTOR seven
segment, Common cathode,
12 digit, multiplexed , LED
display with 12 decimal
points. Overall size is
60 x 18mm and a pinout
diagram is provided. ONLY
$2.50 ea.or 5 for $10 .
ELECTRON IC KEY
KIT
.'
Based on a brand new, very
compact modern EHT flyback
transformer which includes an
EHT diode rectifier. We
supply the transformer, a very
simple circuit, and the
components to suit. All you
need to make a very simple
EHT, DC or pulsed AC
supply. Powered from 12V
DC supply. Great for EHT
experiments, EHT testing ,
plasma displays, etc. Total
price for the transformer and
the components is ONLY:
$20
Use them to activate door '
strikers for entering buildings ,
car alarms , central locking ,
the most secure key ever
(See E.A. July 92) : ON
Item No. 0161
PASSIVE NIGHT
VIEWER
$49.90
SPECIAL<at>
For two keys, and one
decoder kit. Cat. No. GK138.
VULTURE CAR
ALARM
E.A. Nov 89. Best value car
alarm kit!! Fully adjustable
voltage drop and vibration
sensor on board, instant and
delay inputs, flashing light
output, alarm memory, battery
back up provision , provision
for U.H.F. remote control ,
etc. INCREDIBLE VALUE at
a CLEARANCE PRICE OF
ONLY:
$29.90
For the cqmplete P.C.B. and
components kit: Whilst stocks
last. .. (Cat No. GK124)
ELECTRIC FENCE
KIT
Coming soon is our easy to
construct electric fence kit. It
features very low power
consumption, a solar
charging/regulating and
. indicating circuit, and it can
be easily solar powered. The
PCB (Screened and solder
masked) and all components
kit will cost under
$50
The first generation (XX1080)
passive IR night viewer tube
features excellent gain, and
when used with a very low
light objective lens, it can
produce useful images under
almost as little as submoonlight illumination. Cal
also be IR assisted. We will
supply a XX1080 tube, plus a
suitable Lens, plus a kit of
parts for an EHT power supply
(PCB and components only)
for a total price of
$299
$45
LASER POINTER
Th is precision collimator
assembly was removed from
working laser printers and it is
supplied with an extra brand
new laser diode-!o suit. A
produces a well collimated
laser beam at 780nM/5mW.
Barely visible. We also supply
a PCB and components kit
plus instructions , for a
suitable digital driver circuit
that can be used to complete
the laser transmitter. Suitable
for communications , data
links, perimeter protection ,
barcode reading, medical
, use, etc.
$89
(Item No. 0111)
We can also supply a similar
kit which inciudes a laser
diode , unmounted lens, and a
driver kit.
$45
(Item No. 0111 X)
Note that a suitable receiver
for use in perimeter protection
is the one published in E.A.
April 81 .
High quality pen sized 5mW
laser diode pointer for
teachers, doctors, etc . On
$199
Special
Item No. 0101
DIVERGING LENS
SPECIAL
~~
L:.,
A high quality laser beam
diverging (beam expander)
glass lens, mounted on an
alum inium plate, with
mounting screws provided.
Dimensions : 25 x 25 x 6mm.
Use it to expand the laser
beam for Holography. Special
Effects , or one of the two
lenses required to fine focus a
la~er beam , for Surveying and
Bar Code Reading .
SPECIAL
$5.00 ea.
MAL-4: Microcontroller
Aid for Learning; Pt.3
All the parts for the MAL-4 microcontroller are
mounted on a double-sided PC board, so the
assembly is straightforward. All you have to do
is follow the step-by-step instructions.
By BARRY ROZEMA
Numerous hours were spent designing, prototyping and programming the
MAL-4 microcontroller kit but all this
time will have been in vain if you do
not take considerable care in the construction. At the very least, read the
following instructions thoroughly before starting assembly.
If you are an experienced construc46
SILICON CHIP
tor, then the steps may be used as a
guide on~y. However, if you don't have
much experience, then the following
steps should be adhered to rigidly.
Step 1: check the supplied components against the parts list. Contact
the kit supplier immediately if there
are any missing components.
Step 2: check the copper tracks on
the PC board by holding it in front of a
strong light. You should spend at least
half an hour inspecting the board for
breaks, tracks shorted together and
holes not drilled. It is easier to spot
faults on a bare board than it is on a
fully assembled board.
Step 3: solder the IC sockets into
place. Each IC position has pin 1
marked on the PC board and care
should be taken to orient each IC
socket accordingly. Note: some readers may wish to use the more expensive ZIF (Zero Insertion Force) sockets for Ul & UZ.
Step 4: solder all resistors into place,
as indicated on the board and on the
wiring diagram (Fig.2). Bend the leads
E.S.D.
Jf<SRDZEMAYI.'i'll
Fig.3: parts layout for the MAL-4 microcontroller. Note that only the bottom
layer of the board is shown, which is why some tracks appear to end in mid-air.
Follow the instructions in the text when installing the parts on the board.
at right angles with long-nosed pliers
and fit each resistor with its tolerance
band towards the righthand or bottom edge of the board (this will make
checking easier later on). Trim the
excess wire from the soldered joints
on the back of the board.
Step 5: solder the capacitors into
place, making sure that all tantalum
and electrolytic capacitors are correctly oriented (the positive lead is
marked by a plus sign on the PC
board). Trim the excess wire from the
soldered joints on the back of the
board.
Step 6: install the light emitting
diodes (LEDl-18). Most LEDs have a
flat spot on their base to mark the
cathode (K) lead and this should go to
the negative sign, as marked on the
PC board. If the cathode is not marked,
the cathode lead is the shorter of the
two. Note that LED 2 should be a high
intensity type.
Step 7: install diodes D1-D5 & the
bridge rectifier BR1. The cathode terminal is marked by the bar in the
diode outline on the PC board. Check
that the bridge rectifier is correctly
oriented; ie, that its plus and minus
pins go to corresponding pads on the
PC board.
Step 8: install transistors Q1-Q3.
Ql and QZ have their base terminal
towards the righthand side of the
board, while Q3's base terminal is
towards the bottom of the board.
Step 9: install potentiometers VR1
and VRZ. The PC board has been designed to accept potentiometers with
different "footprints". When installing each potentiometer, connect its
wiper terminal to one of the two lower
holes in the footprint on the board.
Step 10: fit the four fuse clips. Note
that some brands of fuse clips must be
oriented correctly to allow the fuse to
fit between them. Fit the two 1A fuses.
Step 11: install the 2MHz crystal.
Note that this crystal should lie flat
on the PC board, as shown in Fig.3.
Step 12: install SIP resistors RP1RP3. Pin 1 is marked on each resistor
pack and this must be aligned with
the pin 1 marking on the PC board.
Step 13: install plugs PL1 and PLZ.
These should both be mounted with
their long pins pointing up.
Step 14: install linking terminals
LNK1-LNK3 with their long pins facing up and fit the shorting straps. In
each case, the shorting strap should
be fitted to the upper position (position 1).
Step 15: solder the display socket
to the PC board. The type of display
that has been supplied will govern
the type of socket and its position.
Display 1 has a 14-pin DIP plug &
socket, while Display 2 has a 14-pin
SIP plug & socket. After fitting the
socket, fit the plug to the underside of
the display (the pins are soldered on
the top of the display board). Don't
plug the display in yet.
Step 16: install 5V regulator U9 and
its heatsink. To do this, first align the
heatsink and regulator assembly with
the board by bending the pins of the
regulator through 90°. Once the correct location has been found, apply a
light film of heatsinking paste to the
back of the regulator, then bolt the
assembly to the PC board using three
3mm screws, nuts and washers (nuts
on the top of the heats ink). Solder the
regulator leads and trim away the excess lead lengths.
Step 17: install the rightangle PCmount DIN socket (IBM type), then
FEBRUARY
1993
47
Table 1: Input/Output Program
Address
Data
· 0030
B6 00
0032
B7 01
0034
BC 30
Table 2: Tone Generator
Address
Data
0040
B6 00
0042
CD 14 A1
0045
1F 02
0047
B600
0049
CD 14 A1
004C
1E 02
004E
BC40
install the 8-way screw connector.
Make sure that the wire entry side of
the screw connector faces the lefthand
edge of the board.
Step 18: install the three PC-mount
toggle switches (Sl, S2 & S3). Note: if
you do not wish to use the switches,
Sl must be replaced with a wire link.
This link should go betweeri the two
lower pads of the Sl terminals.
Step 19: install the PC-mount pushbutton switches (KEY5 & KEY6). Careful inspection of the switch pinouts
and the PC board is necessary to obtain the correct orientation. Try to fit
the switches so that the "RESET" and
"IRQ" prinL markings on Lhe board are
visible (see the notes supplied with
the kit).
Step 20: install the keypad. The
MAL-4 can accommodate several
types of keypads:
(1). Keypad 1: 16-key (4 x 4) x-y,, 9pin.
(2). Keypad 2: 24-key (3 x 8) x-y, 11pin.
(3) . Other: up to 32 keys, hard wired.
If you purchased a complete kit, refer
to the notes supplied with the kit. If
you want to use a socket with the
keypad, this should now be fitted to
the PC board. The keypad is then fitted by plugging it into the socket or by
soldering it directly to the board.
If you use Keypad 2, then skip the
next step.
Step 21: install PC-mount pushbutton switches KEY2, KEY3 & KEY4. As
before, careful inspection of the switch
48
SILICON CHIP
pin outs and the PC board is necessary
to ensure the correct orientation. Try
to fit the switches so that the titles on
the overlay are visible.
Step 22: install the two 8-way DIP
switches by plugging them into their
sockets. These switches should be oriented so that the "ON" position is
towards the bottom of the PC board.
This will set the switches so that "up"
is high and "down" is low.
Step 23: apply 9V AC to the power
connector terminals labelled" AC", or
12V DC between the terminal marked
+12 and GND (your supply should
have a current capability of at least
500mA). Operate switch Sl and check
that the power LED (LED 1) lights.
Now measure the voltage on the +5
terminal of the screw connector block
- it should be between 4.75V and
5.25V. If all is well, disconnect the AC
and continue. If not, remedy the
fault(s) before moving on to the next
step.
Step 24: install ICs U3-U8 by plugging them into their sockets. Make
sure that each one is correctly oriented (double check this) before applying power.
Step 25: apply 9V AC to the power
connector terminals, switch on and
re-check the +5 terminal on the power
connector strip (4.75-5.25V). Check
the temperature of the ICs by feeling
them with your finger - all should be
cool. If all is well, disconnect the AC
and continue. If not, remedy the
fault(s) before proceeding.
Step 26: install the display & the
pre-programmed MCU (U2) by plugging them into their sockets.
Step 27: re-apply power, check the
temperature of the MCU (U2), and
check for signs of distress. Re-check
the +5V terminal on the power connector. If this voltage is low, switch
off immediately and remedy the fault.
If all is well, there should be a message on the LCD (note: contrast pot
VR1 may need to be adjusted). This
message will read "* * * WARNING!
*** RAM POWER FAIL" if you have
no battery back-up supply, or "M.A.L.
Vers 4.XX Enter Mode ... " if you do. If
the display reads "* * * WARNING! * * *
RAM POWER FAIL" then press the
reset key and the display will read
"M.A.L. Vers 4.XX Enter Mode ... "
The construction of the MAL-4
board is now complete. The next step
is check that the various functions
built into the unit are working cor-
rectly. Assuming that you get the messages described in step 2 7 on the display, you should now perform each of
the tests described below.
Keypad test (mode 7)
Step 1: to enter this mode, press the
"7" key at the "M.A.L. Vers 4.XX"
prompt. The display should now show
"KVAL - KYBIN -" on the first line
and "MAL Keyboard TST" on the second line.
Step 2: press any keypad key. The
display should show the KEYVALUE
(the order in which the keys are
scanned) and the KEYBINARY (ie;
the assigned binary value for a given
key).
Step 3: press the RESET or IRQ
switch key to leave mode "7". This
will display the "M.A.L. Vers 4.XX"
prompt again.
Display test (mode 8)
Step 1: press the "8" key at the
"M.A.L. Vers 4.XX" prompt. The display should rotate all its characters to
the right from a flashing cursor.
Step 2: press the RESET or IRQ key
to leave mode "8" and display the
"M.A.L. Vers 4.XX" prompt again.
Keyboard.test (mode D)
Step 1: set the DIP switches on PORT
D (DIP SW2) as shown below:
DIP
SW2
7
X
E
5
4
3
2
1
0
on on off off off off off
Step 2: plug an IBM XT compatible
keyboard into the DIN socket on the
lefthand side of the board.
Step 3: press the "D" key from
"M.A.L. Vers 4.XX" prompt. The display should now show "Keyboard
Data" on the first line, while the second line will be blank.
Step 4: press any key on the IBM
XT keyboard. The display should
show the data that is sent from the
keyboard in hexadecimal format,
while the Port B LEDs will display
the da,ta in binary.
Step 5: press the RESET or IRQ key
to leave mode "D" and display the
"M.A.L. Vers 4.XX" prompt again.
Simple test programs
Tables 1, 2 & 3 list some simple test
programs for the MAL-4. Enter them
using MODE-0 and run them using
MODE-1.
Table 3: Yes/No Decision Maker
Address
Data
0060
CD 12 05
0063
AE 10
0065
CD 11 CC
0068
AE 11
006A
CD 11 FE
006D
CD 13 2E
0070
4C
0071
3D D3
0073
27 F8
0075
A4 01
0077
26 07
0079
AE12
0078
CD 11 FE
007E
20 05
0080
AE13
- 0082
PCB and
SCHEMATIC CAD
r------·~----------- ·-·?t~ :
/ TV IF AMPLIFIE
-
/ "I
rl-f-t----H.lm,.
1!,
,._
.
•
~
C-Uiiiflt•
.
·-:
j•4 :
.....
~
:
CD 11 FE
II
mllll
1111111•111111111111111 11>1 1111111111
• 1.... '·""''"'lf•Nn,w
0085
A604
0087
CD 14 F3
008A
20D7
0100
54 68 65 20 41 6E 73 77 65 72 20 69 73 20 2D 3E
0110
50 72 65 73 73 20 61 20 48 65 79 20 4E 4F 57 21
• Design Single sided, Double sided
and Multilayer boards
0120
2D 2D 2A 2A 20 20 59 45 53 21 20 20 2A 2A 2D 2D
• Provides Surface Mount support
0130
2D2D28282020204E4F20202028282D2D
• Standard output includes Dot
Matrix/Laser/Inkjet printers,
Pen Plotters, Photo-plotters and
NC Drill
Table 1 shows an input/output program. It simply takes the data on the
input port (Port A) DIP SW1 and displays it on the output port (Port B)
LEDs.
Table 2 lists a tone generator program, which generates a variable tone
from the external loudspeaker. This
tone ranges in frequency from 20Hz
to 5kHz and is set by the Port A DIP
switch (SW1).
Finally, Table 3 shows a program
that generates a random YES/NO decision when you press any key on the
keyboard.
Monitor operation
The monitor program, which is in
the MC68HC705C8 EPROM, allows the
user to access RAM, ROM and all the
various registers within the single chip
microcontroller. A detailed description of the operation of this monitor
program follows.
When power is applied or the RE-
EASY-PC
• Runs on PC/XT/AT/286/386 with
Hercules, CGA, EGA or VGA.
SET button is pressed, the display
will show the prompt; ie, "M.A.L.
Vers 4.XX. Enter Mode ... " This means
that you may enter a mode of operation by pressing any of the keys indicated in Table 4.
A detailed description of each mode
follows:
Mode "O" - Load, Examine or
Modify Memory.
Step 1: to enter this mode (Mode 0),
press the "O" key when the "M.A.L.
Vers 4.XX" prompt is displayed. The
display will show "Ad.XXXX". The
"Ad." is the ADDRESS prompt and
indicates that the next four digits contain an address location.
Step 2: enter desired address. If the
microcontroller has just been reset,
then the "XXXX" may contain anything. Conversely, if the microcontroller has not just been reset, the
"XXXX" will contain the last address
entered.
The address displayed after the
• Award winning EASY-PC is in
use in over 12,000 installations in
70 Countries World-Wide
• Superbly Easy to use
• Not Copy Protected
Options: • 1000 piece Schematic
symbol library
• Surface Mount symbol
library
• Gerber Import facility
For full info 'phone, fax or write:
BTC
PO BOX432
GARBUTT 4814 QLD.
PH (077) 21 5299
FAX (077) 21 5930
FEBRUARY
1993
49
Table 4: Monitor Operating Modes
Key
Mode Of Operation
0
Load, examine or modify memory
1
Run a program from a given location
2
Disassemble program ·froln a given location
3
No function
4
No function
5
No function
6
Keyboard beep on/off
7
MAL keyboard test
8
Test MAL display
9
No function
A
Print all RAM contents
B
No function
C
No function
D
Test IBM keyboard raw data
E
Test IBM keyboard characters
F
Shut down CPU & save RAM
ENTER
No function
INC
No function
DEC
No function
"Ad." prompt will be the address that
is to have data loaded, examined or
modified. While the display shows
"AdJOCXX", a 4-digit address may be
entered via the keypad. The increment and decrement keys may be used
to increment or decrement the 4-digit
address by one.
Step 3: press the ENTER key when
the correct address is displayed. The
display will now show "Ad.XXXX
Data YY". The last two digits ("YY")
contain the data that is in the address
location displayed.
Step 4: load, examine or modify the
data using the keypad.
Step 5: increment or decrement to
the next address location (use the increment and decrement keys).
Step 6: repeat steps 4 & 5 until you
are finished.
Step 7: press the ENTER key to leave
mode "0". The display will show the
"M.A.L. Vers 4.XX" prompt again.
Note: when the data is displayed,
the address location is constantly being interrogated and displayed at a
rate of once every few milliseconds.
Thus, if the data does not respond to
key entries, then the address indicated is "read only".
This also means that if the data
changes, then the display will show
the change almost instantly. This may
be useful in monitoring an input port.
MODE 1: Run a program from a
given location.
Step 1: to enter this mode, press the
Where to buy the kit
Parts for the MAL-4 Microcontroller Aid For Learning are available from E.S.D.,
PO Box 73, Glenbrook, NSW 2773. Phone (047) 39 4039. Prices are as follows:
standard kit (incl. manual but does not incl. speaker or plugpack) - $249.00;
standard kit with ZIF sockets plus toggle switches -$306; PC board only- $80;
programmed MCU & manual - $48. Please add $10 for postage inside NSW,
$15 for postage interstate. Payment should be made by cheque or money order.
Note: copyright© of the PC board is retained by Electronic System Designs.
50
SILICON CHIP
"1" key when the "M.A.L. Vers 4.XX"
prompt is displayed. The display will
show "Ad.XXXX Run". The "Ad." is
the address prompt and indicates that
the next four digits contain an address location. The "Run" prompt
indicates that you are in the run mode.
Step 2: enter the desired address. If
the microcontroller has just been reset, then the "XXXX" may contain
anything. If the microcontroller has
not just been reset, then the "XXXX"
will contain the last address entered.
The address displayed after the
"Ad." prompt is the address that the
program will run from. While the display shows "Ad.XXXX", a 4-digit address may be entered via the keypad.
The increment and decrement keys
may be used to increment or decrement the 4-digit address by one.
Step 3: when the correct address is
displayed, press the ENTER key. The
microcontroller will jump to the address that was in the display and run
from there. The display will have
"Ad.XXXX Run" on the first line and
"Program Running" on the second
line.
Mode 2: Disassemble a program
from a given location.
Step 1: press the "2" key when the
"M.A.L. Vers 4.XX" prompt is displayed . The display will show
"Ad.XXXX" on the first line and "Disassemble from" on the second line.
The "Ad." prompt indicates that the
next four digits contain an address
location.
Step 2: enter the desired address
via the keypad, or use the increment
and decrement keys to increment or
decrement the 4-digit address by one.
The address displayed after the "Ad."
prompt will be the address of the first
instruction that is to be disassembled.
Step 3: when the correct address is
displayed, press the ENTER key. The
display will show the address and a
1, 2 or 3 byte op-code on the first line
and the mnemonic and operand on
the second line.
Step 4: increment to the next address.
Step 5: repeat step 4 until you are
finished.
Step 6: press the enter key to leave
mode "2 ". The display will show the
"M.A.L. Vers 4.XX" prompt again.
MODE F: Shut down CPU
&save RAM.
Step 1: press the "F" key from
"M.A.L. Vers 4.XX" prompt. The dis-
Table 5: MAL-4 Subroutines
KALEX
Reg.Use
u.
ACC& IX
N
Make port A an input
None
y
Make port A an output
None
y
IX
y
IX
y
LIGHT BOXES
CLR LCD. Home cursor. RST AD.
None
y
• Portuvee 4 • Portuvee 6
• Dual Level
Home cursor line 1 RST AD.$00
None
y
TRIMMER
e ldeal
Description
Name
Address
SETUP
$1180
lnit. 1/0. lnit LCD. Set P.V.
AINPUT
$11BA
AOUTPUT
$11C3
LDISBUF1
$11CC
LDISBUF2
$11FE
CLRDISP
$1205
HOME1
$120E
Load 1st line of LCD with
message pointed to by IX
Load 2nd line of LCD with
message pointed to by IX
The UV People
ETCH TANKS
• Bubble Etch • Circulating
HOME2
$1217
Home cursor line 2 RST AD.$40
None
y
WCTRL
$1220
Write ACC to LCD control Reg.
Ace
y
PCB DRILL
WDATA
$1240
Write ACC to LCD data Reg
Ace
y
• Toyo HiSpeed
RCTRL
$1261
Read LCD control reg . to ACC
Ace
y
MATERIALS
RDATA
$1275
Read LCD data reg. to ACC
Ace
y
WAIT1
$1289
Fixed sous delay
None
y
• PC Board: Riston, Dynachem
e 3M Label/Panel Stock
• Dynamark: Metal , Plastic
DELAY1
$1295
100us times the ACC delay
Ace
y
DELAYS
$12A3
5ms times the ACC delay
Ace
y
SCANKEY
$112E
Scans keypad, sets KEYV AL,
KEYBIN & KEYASCII
None
y
GETROW
$1323
Used by SCANKEY subroutine
Ace
N
CONVTOA
$1317
Used by SCANKEY subroutine
Ace
N
* AUSTRALIA'S N0.1 STOCKIST *
I
VISA
I
40 Wallis Ave, East Ivanhoe 3079.
Phone (03) 497 3422, Fax (03) 499 2381
LSNCON
$13C6
LSN HEX to ASCII via ACC
ACC
y
MSNCON
$13D1
MSN HEX to ASCII via ACC
ACC
y
Old Reprinted Electrical Books
Beeps speaker 1kHz for 0.25s
None
y
None
?
IX
y
None
y
All
N
Ace
y
Build a 40,000 Volt Induction Coil ............ $9
Short Wave Radio Manual (1930) ........ $23
High Power Wireless Equipment (1911) $16
High Frequency Apparatus (1916) ........ $19
Build Short Wave Receivers (1932) ...... $13
Vision By Radio (1925) ......................... $16
1936 Radio Data Book .......................... $12
How to Become a Radio Amateur (1930) $6
All About Aerials ....................................... $5
Television (1938) ...................................... $5
Shortwave Coil Data Book (1937) ........... $5
. 1928 Radio Trouble-Shooting ............... $24
101 Short Wave Hook-Ups (1935) ........ $14
Vacuum Tubes in Wireless's ................. $21
Construction of Induction Coil ............... $21
Tesla: Man Out of Time (biography) ...... $22
Tesla Said, articles by Tesla 292pp ....... $74
My Inventions, by Nikola Tesla 111pp ... $27
Dr. Nikola Tesla - Complete Patents ..... $93
Tesla Coil Secrets ................................. $13
How to Build a Solar Cell That Works ...... $9
191 4 Catalog Electro Importing Co ....... $14
Electric Arc Furnaces ............................... $6
Experimental Television ........................ $25
BEEP
$13DE
DISPADD
$13F9
Displays address in LCD
DISPACC1
$1423
Displays ACC in LCD point.IX
0ISPACC
$1420
Displays ACC in LCD fixed
SETADD
$1447
D10US
$1498
D100US
$14A1
Delay= ACC times 100us
Ace
y
D1MS
$1480
Delay = ACC times 1ms
Ace
y
D10MS
$1409
Delay = ACC times 1Oms
Ace
y
0100MS
$14E6
Delay = ACC times 100ms
Ace
y
D1SEC
$14F3
Delay = ACC times 1s
Ace
y
01MIN
$1500
Delay = ACC times 1 minute
Ace
y
Displays address in LCD from
keyboard
Delay = ACC times 10us
NB: ACC must be > $02
play will show "uP. in stop mode" on
the first line and "SWITCH OFF NOW"
on the second line.
Step 2: switch off the power to the
MAL-4 board.
Step 3: check the battery warning
LED (LED 2). This is used as an ammeter and indicates the relative power
consumption of the MCU. When the
MCU is in the stop mode, the LED
will not light. If the LED is illuminated, repeat steps 1-3.
Subroutines
Finally, the MAL-4 has a number of
subroutines that the programmer may
find useful. Table 5 lists mos~ of these
subroutines and their addresses. SC
Allow 15 weeks for delivery of some items.
Payment can be made by cheque made
out to Plough Book Sales, PO Box 14,
Belmont, Vic. 3216. Phone {052) 66 1262.
F EB R UARY
1993
51
e
ALTR.C>~IC:
COMPONENTS
e
~
jl.--1,,
L..JAj-/l l.--&.J&.J
AUSTRALIA
WIDE
.
,~,f-HMLTi■OIII
;· ~ IT ~-:!i11ur·~~ f, W.v~
1993
/fi'I
~
ELECTRONIC COMPONENTS CATALOGUE
YOURS FREE with this month's Silicon Chip and Electronics Australia Magazines
OR Send $1.00 to cover P & P to: ALTRO NI CS MAIL ORDER, PO BOX 8350, Stirling Street, Perth WA 6849
Our 1993 Catalogue has even more fantastic new products and greater value than last
year's. We still offer the technical help that only a staff of electronic enthusiasts like yourself is able to give. Of course, in addition to this we have our FAMOUS OVERNIGHT
DELIVERY Australia wide and Bankcard phone order service to 4pm (E.S.T.) Monday to
Friday. All on our quality products at DIRECT IMPORT PRICES that enables YOU TO
SAVE UP TO 50% off competitors' prices.
Jack O'Donnell
Managing Director
Rectangular Piezo
Tweeter
removing
small surface
scratches and general dirt and grime.
A 9220 NORMALLY $1 7-
95
$7·95
Th is Month Only
Outside diam eter
size of 144mm x
67mm. Rated to
IS Watts.
Clearout
C 6120 NORMALLY $19
This Month Only
50
00
$10·
Laboratory Power Supply Super Small PIR
(EA May '85)3-50 Volts at up to 5 Amps
This supply has been one of our most popular. It
inclu d es the latest refinements and is now housed in
a tough 'ABS'
inStnlment
case. This
compact
version
uses a high
efficiency toroidal transformer
resulting in less heat and weight. Features: •
Exclusive to Altronics • Deluxe instrument case •
Attractive silk screened fro nt panel • Pre-drilled and
punched chassis - No holes to d rill • Front panel
drilled for K 3302 option Specifications:
• O utput Voltage: 3 to SOV • Max O utput Current: 5
This neat infra-red
movement detector fea tures triple
pu lse count and
will easily connect
to most alarm systerns. Ideally suited to the S 5490
alarm opposite.
$
S 5302
·
S 5315 NORMA LLY $19
This Month Only $
95
7
Oxygen
Free Cable
We have a limited supp ly of OFC cables in
two varieties.
Both 2 RCA to 2 RCA
with earth leads.
P 0446 900mm in length, Normally
This Month Only
$16-00
$10
P 0448 1.8m in length Normally $19·50
This Month Only
$14
3 Sector Home Alarm
wea th er-proof
this horn is ideal
M 9090 Power Supply & Backu p Battery to Suit $69·•s
Sn Ho
.. canM Til.oNics('"
1 4~~••~ri~I to ~'!.'t1
With this simple device
you can monitor any
door in your house. This
two piece alarm consists
of a Control box and a
magnet. The magnet
simply onto the door
frame w hile the control
box is mounted on the
door, so that they are
opposite when the door
is closed. Easy to use
on / off switch. Built-in beeping buzzer
sounds w hen tripped. Requires 9V battery.
This ·alarm control panel features stylish and compact good
looks It can be either surface or fl ush mounted to blend
smoothly into any decor.
Features: • 4 digit PIN code to arm a nd disarm panel • 3
Independent Protection Circuits 24 hour fire/ panic, external
and internal (isolatable) • All Sectors are Compatible with
NO and NC Switches • All Sectors are Sealed with End-OfLine Resistors • Adjustable Timers for Entry Delay and Siren Duration • Fits Into standard
3 gang wall plate • Plug in wiring harness supplied
00
00
S 5490 Normally $119· , This Month Only
·
62
1----------- --t
Amps Max • Floating Output • Ripp le: Less than
Sm V • Dual Meters
Door Alarms
Economical and
$89
K33oo$195·
______
_J~~~=====--_j..:.:=:.::.::::__:=====:.J Mini Home Teleplwne Exchange Kit
00
Casio Two Colour Printing
Calculator
•
•
•
•
•
•
•
•
Black print and red print to subtractions
Sub-total total
Item counting
Average function
Save Over 50%
3 digit comma markers
Full decimal system
O perates on 4 x Aa power supply
Includes one roll of 58mm paper and d ust cover
00
X 2125 Normally $149·
This Month Only
$69·00
This grea t unit allows you to place calls on
hold, intercom other extensions, answer calls
from any extension and transfer calls. It is
expandable up to 10 extensions, and is compatible with all DTMF (touch tone) telephones. Operation is as simple as pressing '* '
to place a call on hold and press the extension
number (0.9) and the respective station rings.
Once answered you have a two way intercom
with which you can announced call. To pick
up the incoming call from hold press#. A neat fea ture is at
extensions will ring w hen
an incoming call is placed on hold fo r 30 seconds so that it won't be forgotten. The basic kit
is complete with power supply, case and facili ties for 3 extensions. Extra extension boards
allow expansion in multiples of 3. Fantastic for home or small office. No more shouting
from room to room. Not Austel approved.
00
95
. Board
K 1430 Baste KJt
K 1435 Expansion
. . $189·
$79·
PHONE ORDER- FREECALL 008 999 007
AUSTRALIAWIDE
Protector Car Alarm
Kit
What a bargain!
This amazing
kit comes complete with 2
piezosiren,
dash lamp
flasher, battery back up, pin sw itches, sticker, case and all components required to
assemble the kit. It even has an ignition
kille r built in. At this prices they won't last.
K4370 NORMALLY $129•00
$59·00
Digital Storage
C.R.O. Adaptor for
P.C.'s Kit
This Month Only
- -- - - - - - - - - - - - - i
e
~
J l., i-
L.J
A// 1 l.,v °
This great kit enables a P.C. user lo capture
interest then save them lo disc. The unit has
32K of storage memory and a sampling rate
of over 600K samples per second . Input
level of up to 2.5 Volt. Full sampling rate
between 15K s/ s to over 600K s/ s. Inpu t
impedance of JM ohm.
K 2805
$63·50
. $ 19-95
K 2806 5.25" PC Software to SUII
. $ 1 9-95
K 2807 3.5" PC Software to Suit
--------------Digital Headphones
These superb lightweight Hi-fi Stereo
Headphones fea ture
• Super comfortable
foam ear muffs
~ 29mm samarium
cobalt speakers
• Sensitivity of
l OOdB / 32
ohms / 250mW
• Supplied with 2.Sm coiled lead and
3.5mm gold plated stereo plug and 6.35mm
gold plated stereo adaptor a t no extra cost.
C 9002 NORMALLY $24·95
ALTR.C>~IC::
Desolder
Bulbs
Video to TV
Transmitter Kit
COMPONENTS
Soldering Iron
• 370'C.
• Fixed
De-Solders with an
ciency
1 - - - - - -- - - - - - - -- --i
This kit enables you to transmit TV signals
from the UHF output of your TV on your
VCR to a second TV set in the house. The kit
is complete with box and has a range of
about 20 metres. Requires 12 Volts DC (p ictured without case-included).
K 5860 NORMA LLY $74·95
This Month O nly
$49·oo
Texas Instruments
Book
Clearance
a waveform and zoom in to segments of
e
universal
Remote
Control
This Universal Remote
Control makes all o ther
remotes superfluous.
Designed to combine all
infra red remo te controls into one handy
unit. No more searching through piles of
remotes.
95
A 1000
$69·
We only have a select
few of these high
standard Texas
Instruments data
books left. So be
quick as stocks won't
last.
PCB Moun
Blocks
$20·00
00
B 1208 TI Linear Applications Vol 2 $20·
00
B 1216 TI MOS Memory Data Book $2600
B ll18 TI Linear and Interface Orruits $20
B U06 TI Linear Applications Vol 1
Just the shot fo r wire termination to PCB for your
latest project. Enables easy
connection (and disconnection) o f wire and cables to
a PCB. 45' type. Available
in 2 and 3 way configurations.
P 2042 2 WayWAS .~, NOW ONLY ,3041 ea
patented heating element • Iron clad,
chrome plated, long life interchangeable
tips. Tip life expectan cy is many times that
of conventional plated tips. Supplied with T
2424 Tip. Energy authority approved.
95
T 2420
$27·
Hole Punch Set
Cuts holes in
metal upto
1.6mm(16
gauge).Set
5 punches
tapered rea
er. Pun ch
sizes, 16
25mmand
T2360 NO
ThiiiMonth
12V DC at 2
Amps full y
regulated.
250V AC inp
to 2 x binding
posts. Allowing v ·
These supplies are j
bility is in need.
M 9050 NORMALL
Palm-Grip Series
P20433WayWAS ,SSq,NOW ONLY .4541 ea
Hand Tools .-------,,-_,..,.., _ _ _ __ _ _ _ _....,__ _ _ _ _ _ _ __
A must for all tool boxes.
Handy palm-grip size lea- ;n'i,;;,F.;ro,;~~-'
tures spring return and sta
struction.
T 2710 Flat Nose Pliers
T 2720 Needle Nose Pliers
T 2730 Curved Needle Nose Pli_
·e__
rs_ _--,
95
ALL NORMALLY $9· ea
.95
This Month Only
ea
$7
BUYALL
FO R
$18
High Energy Rack
Cases
For very high heat dissipation, this design
allows the fitting of computer type fans to
inside back of rear panel, adjacent to each
respective heatsink.
3 Unit Rack Size (130mm x 440mm x 252mm)
H 0417 Silver Painted Aluminium Front Panel
H 0418 Black Painted Alu minium Front Panel
This lightweight,
comfortable tool
cuts, clinches and
burnished compo00
N ow Onl
nents leads in one
....;;.;.;;.;.;...;;.;;;;;....i.;=;....--------t single stroke.
Rugged aluminium body with durable tool steel mechanism.
SPST chassis mount. With
Limited stocks!
built in 240VAC Neon light.
T 2800 NORMALLY $35·oo
$
_
.
Clearing out at Only 2 0 00
S3218
ea
22·
Telephone
Type
.l
Keypad
I
3 x 4 wa y matrix, as
used with DTMF telephones and some
security applications.
S 5380
$5·00
.99(
L__
_::=::!:..::.:.:. ::::.::.:::::....:::..=-=--i-------=::::::':::::=====~
High Quality Polypropyl.--e_n e_ __,
Telep
Speakers at 1992 Prices Hurry - Stocks Limit
Bell
Most 'state of the art' hig h performance speaker systems use either bextrene or polypropylene cone material in their woofers. This development has given significant improvement in bottom end frequency
response and cabinet size reductions.
50
C 3045 6.5" Midrange 30 Watts Nom/ 50 Watts Max
C 3055 6.5" Woofer 30 Watts Nom / 50 Wa tts Max
$2 7$29.95
C 3060 8" Woofer 60 Watts Nom / 100 Watts Max
$49.95
C 3065 10" Woofer 60 Watts Nom/ 100 Watts Max
$69 .00
C 3070 12" Woofer 100 Watts Nom /150 Watts Max $99
.00
C 3075 15" Woofer 120 Watts Nom / 200 Watts Max $ 1 29
.00
This
handy
line unit
allows
you to
hear the
telephone
ringing
outside in the shed or even those who have
trouble hearing the telephone inside.
Simply connects via a double adaptor to the
telephone line. Telecom approved.
P 0996 Was $29·50 ea,
This month only
$27·00
Top quality blank panel clearout. All stock
must go at t h ese crazy prices. Stock is limited with definitely no backorders. at these
3 Unit-ALL 512·95
H 0423 Nat Alum
H0433Grey
Heavy Duty Lamp
Relays
Fully internally fused
(30 Amp x 2) double
pole 12V relays suitable for headlights,
ho rns or any situation
where heavy duty
switching is a mus t.
50
S 4335 Were $13·
Now clearing at
$8·00
PHONE ORDER- FREECALL 008 999 007
Silicon Chip
BACK ISSUES
May 1989: Electronic Pools/Lotto Selector; Synthesised Tom-Tom; Biofeedback Monitor For Your
PC; Simple Stub Filter For Suppressing TV Interference; LED Message Board, Pt.3; Electronics
For Everyone - All About Electroly1ic Capacitors.
June 1989: Touch-Lamp Dimmer (uses Siemens
SLB0586); Passive Loop Antenna For AM Radios; Universal Temperature Controller; Understanding CRO Probes; LED Message Board, Pt.3.
July 1989: Exhaust Gas Monitor (Uses TGS812
Gas Sensor); Extensibn For The Touch-Lamp
Dimmer; Experimental Mains Hum Sniffers; Compact Ultrasonic Car Alarm ; NSW 86 Class Electric
Locomotives.
July 1988: Stereo Control Preamplifier, Pt.2; Fitting A Fuel Cut-Off Solenoid To Your Car; Booster
For TV & FM Signals ; The Discolight Light Show,
Pt.1 ; Tone Burst Source For Amplifier Headroom
Testing; What Is Negative Feedback, Pt.3.
December 1988: 120W PA Amplifier (With Balanced Inputs), Pt.1 ; Diesel Sound Generator; Car
Antenna/Demister Adaptor; SSB Adaptor For
Shortwave Receivers ; Why Diesel Electrics Killed
Off Steam ; Index to Volume 1.
August 1988: Building A Plasma Display; Universal Power Supply Board ; Remote Chime/Doorbell; High Performance AC Millivoltmeter, Pt.1;
Discolight Light Show, Pt.2 ; Getting The Most Out
Of Nicad Batteries; Data On Insulated Tab Triacs.
January 1989: Line Filter For Computers ; Ultrasonic Proximity Detector For Cars; 120W PA Amplifier (With Balanced Inputs) Pt.1; How To Service Car Cassette Players; Massive Diesel Electrics In The USA; Marantz LD50 Loudspeakers.
September 1989: 2-Chip Portable AM Stereo
Radio (Uses MC 13024 and TX7376P) Pt.1 ; AlarmTriggered Telephone Dialler; High Or Low Fluid
Level Detector; Simple DTMF Encoder; Studio
Series 20-Band Stereo Equaliser, Pt.2; Auto-Zero
Module for Audio Amplifiers (Uses LMC669).
September 1988: Hands-Free Speakerphone ;
Electronic Fish Bite Detector; High Performance
AC Millivoltmeter, Pt. 2; Build The Vader Voice ;
Motorola MC34018 Speakerphone IC Data; What
Is Negative Feedback, Pt.4.
February 1989: Transistor Beta Tester; Minstrel
2-30 Loudspeaker System; LED Flasher For Model
Railways; Build A Simple VHF FM Monitor (uses
MC3362), Pt. 1; Lightning & Electronic Appliances ;
Using Comparators to Detect & Measure.
October 1989: Introducing Remote Control; FM
Radio Intercom For Motorbikes Pt.1; GaAsFet
Preamplifier For Amateur TV; 1Mb Printer Buffer;
2-Chip Portable AM Stereo Radio, Pt.2; Installing
A Hard Disc In The PC.
October 1988: Stereo FM Transmitter (Uses
Rohm BA1 404); High Performance FM Antenna;
Matchbox Crystal Set ; Electronic House Number;
Converting · A CB Radio To The 28MHz Band;
Queensland's Powerful Electric Locomotives.
March 1989: LED Message Board, Pt.1 ; 32-Band
Graphic Equaliser, Pt.1; Stereo Compressor For
CD Players; Amateur VHF FM Monitor, Pt.2; Signetics NE572 Compandor IC Data; Map reader
For Trip Calculations; Electronics For Everyone Resistors.
November 1989: Radfax Decoder For Your PC
(Displays Fax, RTTY & Morse); Sensitive FM Wireless Microphone; FM Radio Intercom For Motorbikes, Pt.2; 2-Chip Portable AM ~ereo Radio ,
Pt.3; Floppy Disc Drive Formats & Options; The
Pilbara Iron Ore Railways.
April 1989: Auxiliary Brake Light Flasher; Electronics For Everyone: What You Need to Know
About Capacitors; Telephone Bell Monitor/ Transmitter; 32-Band Graphic Equaliser, Pt.2; LED Message Board, Pt.2.
December 1989: Digital Voice Board (Records
Up To Four Separate Messages); UHF Remote
Switch ; Balanced Input & Output Stages; Data
For The LM831 Low Voltage Amplifier IC; Install
A Clock Card In Your PC; Index to Volume 2.
November 1988: 120W PA Amplifier Module
(Uses Mosfets) ; Poor Man's Plasma Display;
Automotive Night Safety Light; Adding A Headset
To The Speakerphone; How To Quieten The Fan
In Your Computer; Screws & Screwdrivers, What
You Need To Know; Diesel Electric Locomotives.
l.
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L----------------- --- ---------. -------- - -54
SILIC O N CHIP
January 1990: High Quality Sine/Square Oscillator; Service Tips For Your VCR ; Speeding Up
Your PC; Phone Patch For Radio Amateurs; Active Antenna Kit; Speed Controller For Ceiling
Fans; Designing UHF Transmitter Stages.
February 1990: 16-Channel Mixing Desk; High
Quality Audio Oscillator, Pt.2; The Incredible Hot
Canaries; Random Wire Antenna Tuner For 6
Metres; Phone Patch For Radio Amateurs, Pt.2;
PC Program Calculates Great Circle Bearings.
March 1990: 6/12V Charger For Sealed LeadAcid Batteries; Delay Unit For Automatic Antennas; Workout Timer For Aerobics Classes; 16Channel Mixing Desk, Pt.2; Using The UC3906
SLA Battery Charger IC.
April 1990: Dual Tracking ±S0V Power Supply;
VOX With Delayed Audio; Relative Field Strength
Meter; 16-Channel Mixing Desk, Pt.3; Active CW
Filter For Weak Signal Reception ; How To Find
Vintage Radio Receivers From The 1920s.
May 1990: Build A 4-Digit Capacitance Meter;
High Energy Ignition For Cars With Reluctor Distributors; The Mozzie CW Transceiver; Waveform
Generation Using A PC, Pt.3; 16-Channel Mixing
Desk, Pt.4.
June 1990: Multi-Sector Home Burglar Alarm;
Low-Noise Universal Stereo Preamplifier; Load
Protection Switch For Power Supplies; A Speed
Alarm For Your Car; Design Factors For Model
Aircraft; Fitting A Fax Card To A Computer.
July 1990: Digital Sine/Square Generator, Pt.1
(Covers 0-S00kHz); Burglar Alarm Keypad & Combination Lock; Simple Electronic Die; Low-Cost
Dual Power Supply; Inside A Coal Burning Power
Station; Weather Fax Frequencies.
·
Batteries, Pt.2; How To Design Amplifier Output
Stages; Tasmania's Hydroelectric Power System.
Call Timer; Coping With Damaged Computer
Directories ; Valve Substitution In Vintage Radios .
March 1991: Remote Controller For Garage
Doors, Pt.1; Transistor Beta Tester Mk.2; Synthesised AM Stereo Tuner, Pt.2; Multi-Purpose 1/0
Board F.or PC-Compatibles; Universal Wideband
RF Preamplifier For Amateurs & TV ; A Look At
The Config.Sys & Ansi.Sys Files.
April 1992: lnfrared Remote Control For Model
Railroads ; Differential Input Buffer For CROs; Studio Twin Fifty Stereo Amplifier, Pt.2; Understanding Computer Memory; Switching Frequencies in
Model Speed Controllers; Aligning Vintage Radio
Receivers, Pt.1.
April 1991 : Steam Sound Simulator For Model
Railroads; Remote Controller For Garage Doors,
Pt.2; Simple 12/24V Light Chaser; Synthesised
AM Stereo Tuner, Pt.3; A Practical Approach To
Amplifier Design, Pt.2; Playing With The Ansi.Sys
File; FSK Indicator For HF Transmissions .
. May 1992: Build A Telephone Intercom ; LowCost Electronic Doorbell ; Battery Eliminator For
Personal Players; lnfrared Remote Control For
Model Railroads , Pt.2; A Look At Large Screen
High Resolution Monitors; OS2 Is Really Here;
Aligning Vintage Radio Receivers , Pt.2.
May 1991: Build A DTMF Decoder; 13.SV 25A
Power Supply For Transceivers; Stereo Audio
Expander; Fluorescent Light Simulator For Model
Railways; How To Install Multiple TV Outlets, Pt.1;
Setting Screen Colours On Your PC.
June 1992: Multi-Station Headset Intercom, Pt.1 ;
Video Switcher For Camcorders & VCRs ; lnfrared
Remote Control For Model Railroads , Pt.3; 15Watt 12-240V Inverter; What's New In Oscilloscopes? ; A Look At Hard Disc Drives.
June 1991: A Corner Reflector Antenna For UHF
TV; 4-Channel Lighting Desk, Pt.1; 13.SV 25A
Power Supply For Transceivers; Active Filter For
CW Reception; Electric Vehicle Transmission
Options; Tuning In To Satellite TV, Pt.1 .
July 1992: Build A Nicad Battery Discharger; 8Station Automatic Sprinkler Timer ; Portable 12V
SLA Battery Charger; Off-Hook Timer For Telephones; Multi-Station Headset Intercom , Pt.2;
Understanding The World Of CB Radio ; Electronics Workbench For Home Or Lab.
July 1991: Battery Discharge Pacer For Electric
Vehicles ; Loudspeaker Protector For Stereo Amplifiers; 4-Channel Lighting Desk, Pt.2; How To
Install Multiple TV Outlets, Pt.2; Tuning In To
Satellite TV, Pt.2; PEP Monitor For Transceivers.
August 1991: Build A Digital Tachometer; Masthead Amplifier For TV & FM; PC Voice Recorder;
Tuning In To Satellite TV, Pt.3; Installing Windows On Your PC; Step-By-Step Vintage Radio
Repairs.
August 1990: High Stability UHF Remote Transmitter; Universal Safety Timer For Mains Appliances (9 Minutes); Horace The Electronic Cricket;
Digital Sine/Square Wave Generator, Pt.2.
September 1991: Studio 3-55L 3-Way Loudspeaker System; Digital Altimeter For Gliders &
Ultralights, Pt.1 ; Build A Fax/Modem · For Your
Computer; The Basics Of AID & DIA Conversion;
Windows 3 Swapfiles, Program Groups & Icons.
September 1990: Music On Hold For Your Telephone; Remote Control Extender For VCRs;
Power Supply For Burglar Alarms; Low-Cost 3Digit Counter Module; Simple Shortwave Converter For The 2-Metre Band.
October 1991: Build A Talking Voltmeter For
Your PC, Pt.1; SteamSound Simulator Mk.11; Magnetic Field Strength Meter; Digital Altimeter For
Gliders & Ultralights, Pt.2; Getting To Know The
Windows PIF Editor.
October 1990: Low-Cost Siren For Burglar
Alarms; Dimming Controls For The Discolight;
Surfsound Simulator; DC Offset For DMMs; The
Dangers of Polychlorinated Biphenyls; Using The
NE602 In Home-Brew Converter Circuits.
November 1991: Colour TV Pattern Generator,
Pt.1; Battery Charger For Solar Panels; Flashing
Alarm Light For Cars; Digital Altimeter For Gliders
& Ultralights, Pt.3; Build A Talking Voltmeter For
Your PC, Pt.2; Error Analyser For CD Players
Pt.3; Modifying The Windows INI Files.
August 1992: Build An Automatic SLA Battery
Charger; Miniature 1.5V To 9V DC Converter;
The lnterphone Digital Telephone Exchange, Pt.1 ;
Dummy Load Box For Large Audio Amplifiers;
Internal Combustion Engines For Model Aircraft;
Troubleshooting Vintage Radio Receivers .
September 1992: Multi-Sector Home Burglar
Alarm; The lnterphone Digital Telephone Exchange, Pt.2; General-Purpose 3½- Digit LCD
Panel Meter; Track Tester For Model Railroads;
Build A Relative Field Strength Meter; Internal
Combustion Engines For Model Aircraft, Pt.2.
October 1992: 2kW 24VDC To 240VAC Sinewave Inverter; Multi-Sector Home Burglar Alarm,
Pt.2; Mini Amplifier For Personal Stereos; Electronically Regulated Battery Charger (Charges 6V,
12V & 24V Lead-Acid Batteries) ; Internal Combustion Engines For Model Aircraft, Pt. 2.
November 1992: MAL-4 Microcontroller Board,
Pt.1 ; Simple FM Radio Receiver; lnfrared Night
Viewer; Speed Controller For Electric Models,
Pt.1; 2kW 24VDC To 240VAC Sinewave Inverter,
Pt.2; Automatic Nicad Battery Discharger; Modifications To The Drill Speed Controller.
November 1990: How To Connect Two TV Sets
To One VCR; A Really Snazzy Egg Timer; LowCost Model Train Controller; Battery Powered Laser Pointer; 1.5V To 9V DC Converter; Introduction To Digital Electronics; Simple 6-Metre Amateur Transmitter.
December 1991: TV Transmitter For VCRs With
UHF Modulators; lnfrared Light Beam Relay; SolidState Laser Pointer; Colour TV Pattern Generator, Pt.2; Windows 3 & The Dreaded Unrecoverable Application Error; Index To Volume 4.
December 1992: Diesel Sound Simulator For
Model Railroads; Easy-To-Build UHF Remote
Switch ; MAL-4 Microcontroller Board, Pt.2; Speed
Controller For Electric Models, Pt.2; 2kW 24VDC
To 240VAC Sinewave Inverter, Pt.3; High Voltage Probes - Beware The Dangers; Index To
Volume 5.
December 1990: DC-DC Converter For Car Amplifiers; The Big Escape -A Game Of Skill; Wiper
Pulser For Rear Windows; Versatile 4-Digit Combination Lock; SW Power Amplifier For The 6Metre Amateur Transmitter; Index To Volume 3.
January 1992: 4-Channel Guitar Mixer; Adjustable 0-45V BA Power Supply, Pt.1; Baby Room
Monitor/FM Transmitter; Automatic Controller For
Car Headlights; Experiments For Your Games
Card; Restoring An AWA Radiolette Receiver.
January 1993: Peerless PSK60/2 2-Way Hifi
Loudspeakers; Flea-Power AM Radio Transmitter; High Intensity LED Flasher For Bicycles; 2kW
24VDC "(o 240VAC Sinewave Inverter, Pt.4;
Speed Controller For Electric Models, Pt.3.
January 1991: Fast Charger For Nicad Batteries,
Pt.1; The Fruit Machine; Two-Tone Alarm Module; Laser Power Supply; LCD Readout For The
Capacitance Meter; How Quartz Crystals Work;
The Dangers When Servicing Microwave Ovens.
February 1992: Compact Digital Voice Recorder;
SO-Watt/Channel Stereo Power Amplifier; 12VDC/
240VAC 40-Watt Inverter; Adjustable 0-45V BA
Power Supply, Pt.2; Designing A Speed Controller For Electric Models.
February 1991: Synthesised Stereo AM Tuner,
Pt.1; Three Inverters For Fluorescent Lights; LowCost Sinewave Oscillator; Fast Charger For Nicad
March 1992: TV Transmitter For VHF VCRs;
Studio Twin Fifty Stereo Amplifier, Pt.1; Thermostatic Switch For Car Radiator Fans; Telephone
PLEASE NOTE: All issues from November 1987
to June 1988 plus the August 1989 issue are now
sold out. All other issues are presently in stock.
For readers wanting articles from sold-out issues,
we can supply photostat copies (or tearsheets) at
$5.00 per article, including postage. When supplying photostat articles or back copies, we automatically supply any relevant Notes & Errata at no
extra charge.
F EBRUARY
1993
55
Audio leve
meter
with LED readout
This LED VU meter can be used as an adjunct
to the mechanical meters found in older tape
decks & in low-cost audio mixers. Its main
advantages include a fast response time & a
peak hold facility so that you can accurately
set recording levels.
By BERNIE GILCHRIST
When recording audio signals, it's
important that input levels be accurately set in order to obtain good results. If the signal level is set too high,
the recorded signal will sound distorted due to signal overload. On the
other hand, if the input signal level is
set too low, the recording will be noisy,
will have limited dynamic range and
may even suffer from signal dropouts.
The traditional way of monitoring
signal levels is to use a VU (volume
units) meter. In practice, the input
signal level is normally adjusted so
that peak levels register no more than
56
SILICON CHIP
about +3dB. Any more than that and
you run the risk of signal overload.
Mechanical VU meters have one
major disadvantage though - they're
not fast enough to respond to fast
signal transients. The result is signal
clipping and unwanted distortion in
your recordings. By comparison, this
electronic VU meter can respond to
fast transients and also has a peak
hold facility to give you sufficient
time to observe these signal peaks.
Unlike conventional units, this unit
displays the signal level using 12 rectangular LEDs arranged in bargraph
fashion. The reading is scaled in volume units, which is a logarithmic scale
commonly used in audio equipment
for displaying dynamic signal levels.
Table 1 shows the absolute and relative levels for the LEDs when no input attenuation is used; ie, when the
input signal is applied direct to Cl
(see Fig.1).
The peak hold facility involves the
top five LEDs. If the signal peak
reaches these LEDs, then the highest
LED that lights will be held on long
enough for it to be observed, while
the other LEDs in the peak hold section turn off. By this means, any peaks
that are normally too quick to be observed are captured and displayed.
By making a simple circuit modification, two of these VU meters can
Below: the LM317 regulator is secured
to the underside of the PC board using
a screw & nut. The 12 LEDs indicate
the signal level. They can be mounted
separately & wired back to the main
board via a 12-way cable if required.
Of
TABLE 1
1N4002
+11-40V
i
CS +
33
3svw-.,.
ov°+
C4 +
AS
1M
1
sovw-
13
PK OSC
-20dB
LED1
15
D1 16
.,.
-15dB
LED2
D2 17
Rt
33k
-tOdB
LED3
INPUT
R2
47k
GND°+
7
VRt
50k
.,.
.,.
D3 18
IN1(·)
R4
82k
-7d8
LED4
C2 1
SOVW+
04 19
-SdB
LEDS
D5
20
·3dB
LED6
IC1
LB1412
LED
Input Level
Relative Level
1
11mV
-20dB
2
20mV
-15dB
3
35mV
-10dB
4
49mV
-?dB
5
62mV
-5dB
6
78mV
-3dB
7
98mV
-1dB
8
110mV
0dB
9
123mV
+1dB
10
156mV
+3dB
11
196mV
+5dB
12
276mV
+8dB
D6 21
10
~
AO I
-1dB
LED7
D7
OdB LEDS
R6
4.7k
14
D8
.~.
010
11
D11
I
I
I
012
+
BARGRAPH
vu
1
ILED
09
Jf
22
2
3
4
5d8 LE011
5
SdB LE012
K
A
.,.
METER
Fig.1: the circuit is based on an LB1412 display driver (ICl ). The audio signal is
fed in on pin 7, after which it is amplified & detected before being fed to 12
comparator stages. These stages compare the input level against preset
thresholds & operate the appropriate LEDs.
share a common peak hold reset li:rie,
so that the peak LEDs in each channel
switch off at the same time. This enhances the meter display and makes
it easier to adjust recording levels in a
stereo system.
To make the display easy to read,
the bottom seven LEDs are all green
and these correspond to relative signal levels ranging from -20dB to -ldB.
The eighth LED is yellow and corresponds to 0dB, while the top four LEDs
are all red and indicate signal levels
ranging from +ldB to +BdB.
How it works
Let's now take a look at the circuitsee Fig.1. It's based on a single LB1412
IC plus a 3-terminal regulator and a
handful of minor parts.
As can be seen, the audio signal is
fed in via an input attenuator consisting of Rl, R2 & VRl. This circuit
allows the input sensitivity and impedance to be adjusted (see Table 2).
The attenuated signal is then AC-coupled via Cl and R3 to the inverting
input of an op amp inside the LB1412
IC.
ICl is a complete 12-dot red/green
LED level meter on a single chip. It
contains two stages of input amplification, 12 comparator stages, an inbuilt oscillator for peak hold reset,
two constant current sources, and 12
output driver stages for the LEDs. In
addition, there are five RS flipflop
stages which function as latches and
provide the peak hold logic for the
five top LEDs.
The gain of the first op amp stage is
determined by resistors R3 and R4
and, according to the manufacturer's
specifications, must not be made
greater than 4. In this circuit, R3 and
R4 have been selected to give a gain of
3.7.
The output of this first stage is coupled via C2 to the input (pin 9) of the
second stage. This stage functions as
a half-wave detector with a gain of 2.
Its output at pin 10 is filtered by capacitor C3, the value of which determines the attack and decay times of
the display.
If C3 is made too small, the display
will tend to flicker rapidly with low
frequency signals. Conversely, if it is
made too large, the display will not
respond to short peaks or troughs.
The 2.2µF capacitor used in this circuit gives attack and decay times of
approximately 0.5ms and 250ms respectively.
Internal comparators
The output of the detector is fed to
the 12 comparators (one for each LED).
These compare the input level with
the preset threshold levels for the display and operate the appropriate LEDs.
As indicated above, the peak hold
function works by using the internal
latches to gate the top five LEDs. This
latching circuit holds on the highest
LED to be lit until a reset pulse is
received. It also ensures that any lower
LEDs in the peak hold circuit are
FEBRUARY
1993
57
Fig.2: install the
parts on the PC
board as shown in
this wiring diagram,
noting especially
that IC2 is mounted
on the copper side
of the board. The
LED display section
can be separated
from the remainder
of the circuit by
cutting along the
dotted line.
protection diode and about 2V across
the regulator.
A relatively large area of copper is
provided on the PC board to serve as a
heatsink for the LM317. This allows it
to operate continuously from a 40V
supply without overheating, even
with all LEDs turned on. The LM317
has automatic thermal protection but
normally only some of the LEDs are
on, so even with a 40V supply the
power dissipation will be comfortably below its shutdown point.
Finally, link J1 (shown dotted) disables the peak hold circuit by pulling
the reset line of the internal oscillator
to ground. The top five LEDs then
function in the same manner as the
bottom seven LEDs.
Construction
turned off (ie, only one of the top five
LEDs can be lit at any one time).
The reset pulse is supplied by the
internal oscillator, the frequency of
which is determined by R5 (1MQ)
and C4 (1µF). This resets the latches
once every cycle; ie, about every 0.9s
with the values shown. Because the
oscillator is not synchronised to the
signal peaks, the actual peak hold time
depends on just when the peak occurs within the cycle and may be very
short if it occurs just before the reset
pulse arrives.
In practice though, the varying peak
hold time is not all that noticeable
since the effect averages out over time.
Constant current drivers
The two constant current drivers
inside IC1 control the current through
the bottom seven LEDs. LEDs 1-4 share
one constant current driver, while
LEDs 5-7 share the other. Resistor R6
sets the current through these drivers
to about 11mA. Although the current
decreases with an increase in R6, it is
not inversely proportional to R6.
LEDs 8-12 are individually driven
because of their peak hold function,
their current being determined by series resistors R7-R11. Because of this,
their brightness can vary if the supply
voltage to the LB1412 varies but in
this circuit, an LM317 voltage regulator provides a fixed supply voltage of
9.6V.
Actually, the specified supply voltage range for the LB1412 is 10-16V
but tests involving six of these ICs
showed that they all worked down to
8.4V without any problems.
The LM317 voltage regulator allows
input voltages of up to 40V to be used
so that the unit can be connected to
the positive supply rail of most power
amplifiers. The lower supply voltage
limit for the circuit is about 11 V, which
gives approximately 8.4V across the
LB1412 after dropping 0.6V across the
All the parts for the LED VU meter
are mounted on a small PC board
coded ZA-1363 - see Fig.2. You can
install the parts in any order but make
sure that the IC, diode and electrolytic capacitors are correctly oriented.
The LM317 is mounted on the copper
side of the PC board and is secured to
the board using a screw and nut.
If you want the peak hold facility,
link J1 should be omitted. Conversely,
install J1 to disable the peak hold
s ircuit if this feature is not required.
As shown in Fig.2, the circuit is
configured for a sensitivity range of
600mV to 1.5V and a nominal input
impedance of 50kQ (ie, R1 = 33kQ &
R2 = 47kQ). This sensitivity range
should suit most line level signals;
eg, from CD players and tuners. If
required, the sensitivity can be increased to suit signals up to 600mV
by installing a wire link for R1 and
deleting R2.
The most difficult part of the construction is getting the ends of the
LEDs to line up. One technique that
RESISTOR COLOUR CODES
0
0
0
0
0
0
0
0
0
0
58
No.
Value
1
1MQ
82kQ
47kQ
33kQ
22kQ
4.7kQ
1.8kQ
560Q
270Q
1
1
1
1
1
1
5
1
SILICON CHIP
4-Band Code (5%)
brown black green gold
grey red orange gold
yellow violet orange gold
orange orange orange gold
red red orfenge gold
yellow vio et red gold
brown grey red gold
green blue brown gold
red violet brown gold
5-Band Code (1%)
brown black black yellow brown
grey red black red brown
yellow violet black red brown
orange orange black red brown
red red black red brown
yellow violet black brown brown
brown grey black brown brown
green blue black black brown
red violet black black brown
TABLE 2
R1 (ohms)
R2 (ohms)
Sensitivity
0
-
110-600mV
15-50k
33k
47k
600mV - 1.5V
50k
100k
47k
1.5V, - 3V
100k
100k
10k
3V-8V
100k
100k
3.3k
8V- 20V
100k
100k
1.2k
20V- 50V
100k
can be used is to first carefully solder
the two end LEDs so that they are the
same distance from the PC board. The
remaining LEDs can then be installed
and the display pushed against a flat
surface to align the ends of LEDs before soldering.
It is a good idea to initially solder
only one lead of each LED until you
are satisfied that they are all correctly
aligned. Make sure that the LEDs are
correctly oriented - the anode lead is
the longer of the two. Use green LEDs
for LEDs 1-7, a yellow LED for LED 8,
and red LEDs for LEDs 9-12.
To allow for different mounting configurations , the display end of the
board can be separated from the rest
of the circuitry using a fine-bladed
hacksaw. The display can then be connected to the main board via flying
leads, or directly soldered to it at right
angles.
If you are soldering the two boards
together, lightly solder tack the two
end connections first. The angle between the two boards can then be
easily adjusted if necessary before the
PARTS LIST
Input Impedance
1 PC board, code ZA-1363
1 10mm x 3mm-dia. screw, nut &
washer
4 PC stakes
1 S0kn miniature vertical trimpot
Semiconductors
remaining connections are soldered.
If two of these VU meters are to be
used together in a stereo system, then
the following modifications should
be included so that the peak hold
circuits reset together: (1) disable the
p eak hold oscillator on one meter by
removing C4 and R5 ; (2) connect pin
13 of ICl in this meter to ground (ie,
to OV); and (3) connect the reset pins
(11) of the two LB1412 display driver
ICs together.
The oscillator in one unit will now
reset both units simultaneously.
Adjustment
Trimpot VRl is the only component on the PC board that requires
adjustment. If you are using the unit
as an adjunct to a mechanical VU
meter, adjust VRl so that both meters
read the same on a lkHz sinewave
signal.
If you have access to an audio signal generator, you can calibrate the
circuit so that the OVU LED corresponds to a signal level of 775mV at
lkHz.
SC
1 LB1412 display driver (IC1)
1 LM317T regulator (IC2)
1 1N4002 silicon diode (D1)
7 green LEDs (LED1 -LED?)
1 yellow LED (LED8)
4 red LEDs (LED9-LED12)
Capacitors
1 33µF 35VW PC electrolytic
1 4.7µF 25VW PC electrolytic
1 2.2µF 25VW PC electrolytic
2 1µF 50VW PC electrolytic
1 0.1 µF monolithic
Resistors (0.25W, 5%)
1 1MQ
1 82kQ
1 47kn
1 33kn
1 22kQ
1 4.7kQ
1 1.8kQ
5 5600
1 270n
Where to buy the kit
A kit of parts for this project is
available from any Dick Smith
Electronics store or by mail order
from PO Box 321, North Ryde
2113. Phone (02) 888 2105. The
price is $24.95 plus $5 p&p. Quote
Cat. K-5370 when ordering.
Note: copyright of the PC artwork
for this project is retained by Dick
Smith Electronics.
·
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SATELLITE TV SYSTEM
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For many years you have probably looked at sate IIite TV
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You can now purchase the following
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$995
Here's what you get:
• A 1.6 metre prime focus dish antenna,
complete with all the mounting hardware.
• One super low-noise LNB (1.4dB or better).
• One Ku-band feedhorn and a magnetic
signal polariser.
• 30 metres of low-loss coaxial cable with a
single pair control line.
• lnfrared remote control pre programmed
satellite receiver with selectable IF & audio
bandwidth, polarity & digital readout.
Your receiver is pre-programmed to the popular
OPTUS transponders via the internal memory.
AV-COMM Pty Ltd, PO Box 225, Balgowlah NSW
2093. Ph: (02) 949 7417. Fax: (02) 949 7095.
All items are available separately. Ask about our C-band
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1993
59
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The GAG-808G is GW Instruments' latest general purpose
audio oscillator. Being an AC type oscillator ensures a pure,
low distortion sinewave output over the entire frequency
range. A switchable output attenuator, calibrated in steps
of 10 dB, makes the GAG-808G ideal in teaching as well as
service applications. Both the sinewave and square wave
outputs can also be varied by a continuous amplitude
control.
GAG-B0BG 10009
<
CAT No. l0008
CAT. No. 10014
•
•
•
• 2CH Input, auto selection. _
• Dual Decimal Points Indication
• 0.1 Second Gate Time
2Hz-200KHz (5 Ranges)
Sine, Triangle, Square Wave
1 % Typical at 1KHz
$304.00
Frequency Range: 10 Hz to 1 MHz, in 5 ranges
Sinewave Output: < 20 V pk-pk; Distortion < 0.1 %
Squarewave Output: < 10Vpk- pk; Rise timme < 200 ns
Output Impedance: 600 ohm
Stepped Attentuator Oto -50 dB in 10 dB steps
! FUNCTION GENERATORS
$313 & $454
!
GW GFC-F SERIES
►
Competitively Priced
► Professional Quality
GFC 801G 120 MHz 10012
$313.00
Frequency Range: 1 Hz to 120 MHz
Sensitivity: ,;,20 mV 10 Hz to 100 MHz
,;,30 mV 100 MHz to 120 MHz
Display 8 digit display and Gate Time 0.1 s, 1s, 10s
<
CTIC86A
UNIVERSAL COUNTER
$144.00
CAT No. 10007
•
•
•
~
<
~
<
~
CTI C550A
$199.00
550 MHz FREQUENCY COUNTER
$95.00
~
~
$304 1
► Low Distortion Oscillator
~
~
IAUDIO
SIGNAL
GENERATOR
ECONOMICAL BENCH-TOP INSTRUMENTS
10Hz-60MHz Two Ranges
0-9999999 Counts
25mV RMS Sensitivity
•
•
•
CTIC90A
24V 3A DIGITAL POWER SUPPLY
$129,00
CAT No. 10212
Precision 60.0V DVM for Monitoring the regulator output
voltage/current.
Output Voltage: 0-24V
Output Current: 3A
Current Limit: 20mA, 5DmA, 200mA, 500mA, 1A, 3A.
Line Regulation: 0 .1 % against 20% line variation
Load Regulation: 0.5% against 10 to 90% load variation.
INTELLIGENT COUNTERS
$609 !
GWGFC-G SERIES
► Frequency, Period and RPM .Ranges
The GFC-813G is an economically priced 1.3 1 Ghz counter.
Additional features include a continuously variable Gate
Time control as well as adjustable variable Level/Sensitivity.
Front panel switches include AC/DC input coupling. LPF
and attenuator controls.
$609.00
GFC-813 G 10015
Frequency Range: 0.01 Hz to 1.3 GHz, AC or DC coupling
Period Range: 0.6 rpm to 7,200 rpm
Sensitivity: Input A 10 mVat 80 MHz
Input B 50 mVat 1.3 GHz
I UNIVERSAL COUNTERS
CTIC87A
AUTORANGING CAPACITANCE METER
CAT No. M0203
$144.00
$592 !
10 Ranges, fully Automatic with Range
Hold.
Ftill Scale Value From 99.9pF to 99.9mF.
Accuracy 0.5% +/-0.5pF +/-1 Digit.
GFC 8055G 5500 MHz 10013
$454.00
Frequency Range: 1 Hz to 550 MHz
Sensitivity: lnputA ,;, 20 mVat 100 MHz
Input B ,;, 150 mVat 550 MHz
Display 8 digit LED and Gate Time 0.1 s, 1sand 10s
'
ECONOMICAL LABORATORY
GW POWER SUPPLY BASIC FUNCTIONS
Continuously variable voltage and current from zero to
rated limit with FINE and COARSE controls.
Outputs are electronically protected against short circuit or
overload conditions.
The input is fuse protected, with a true 240V AC input.
Automatic Constant Voltage - Constant crossover with
LEDs
CTIC83B
30V 1A DIGITAL POWER SUPPLY
$93,00
CAT No. 10213
Precision 60.0V DVM for Monitoring the regulator output
voltage/current.
Output Voltage: 0-30V
Output Current: 1A (MAX)
Current Limit: 10mA, 50mA, 200mA, 500mA, 1A, 2A
(Approx.)
Line Regulation: 0.1 % against 20% line variation
Load Regulation: 0.5% against 10 to 90% load variation.
I
The GPR-Series includes Floating Output, allowing either
side to be linked to ground. FINE and COARSE voltage and
current control. Clearly marked analogue panel meters,
CLASS2.5
I►
GPC-SERIES
I
TRIPLE Output DC Supplies
► 4 Analogue Panel Meters
MODEL
$458 !
► Inbuilt Logic Probe
► 5V DC Power Supply Output
GPG-8018I0011
GPS & GPR-SERIES
► SINGLE output DC Supplies
► 2 Analogue Panel Meters, V and A
Dual Variable Outputs
Switch selectable configurations Independent both outputs controlled separately
Dual Tracking provides Master/ Slave control voltages
Parallel doubles output current range
Series doubles output voltage range
Single Fixed Output
Each output has an overload indication LED. Both Variable
and Fixed outputs are floating.
5 Hzto 2 MHz (CH 8)
Period Range: 0.5 µ.s to 0.2s, 5 Hz to 2MHz (CH A)
Frequency Ratio Measurement: 11 (CH 8)/12 (CH A)
Totalise Range Oto 99999999 (CH A)
Time Interval Measurement Range 0.5 µ.s to 0.2s
Sensitivity: Input A <150 mVat 175 MHz
Input B < 30 mVat 2 MHz
Display 8 digit LED
I PULSE GENERATORS
I
$458.00
Frequency Range: 0.5 Hz to 5 MHz
Pulse width and spacing independently variable
100 ns to 0.1 s
Functions run, Trigger, Gate, One shot, Square, invert
Outputs: TTL (Fanout 40)
Variable Output (0,5 to 10V) for CMOS
Synchronisation Output (Fanout 10)
GPS-1830
GPR-1810H
GPS-2020
GPR-3060
GPR-6030
GPS-3030D
GPR-6030D
GPC-1850D
GPC-3030D
GPC-1850
GPC-3030
RANGE
0-18V0-3A
0-18V0-10A
0-30V0-3A
0-30V0-6A
0-60V0-3A
0-30V0-3A
0-60V0-3A
2x0-18V5A, 1x5V3A
2x0-30V 3A, 1 x5V 3A
2x0-18V3A, 1x5V3A
2xO-30V 3A, 1x5V 3A
<
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Escort
SPACE SAVER SERIES
EUC-2200 175 MHz 10016
Frequency Range: 5 Hzto 175 MHz (CH A).
$592.00
L--------------------------------------------------- -------------- -
t\
..____·~O ~N'--""""""E-- - -A==- -., --0
- - -.;=-=N:__L,! E
! !~ A-~O~N~E . _____,A
, , _- """"--- ~
E
~ A ""--- - - - "~NE
Ji
uments & Power Supp
T~~§T~FEB'930NLY
>.
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1FUNctloN CENEAAToAs
FROM $4s2 1
GWGFG 2 MHz SERIES
GFG SERiES COMMON FEATURES
Frequency Range 0.2 Hz to 2 MHz, continuously variable.
Output Waveforms sine, triangle, square, TTL pulse and
ramp
Output Level > 20 Vp-p open circuit, 10 Vp-p into 50 ohms
VCF Oto 10V input for 1000:1 output frequency variation DC
offset of :±; 10VDC.
GFG-8016G l0005
► Frequency Counter
$545.00
& 2 M Hz Function Generator
Special Functions Frequency Counter
• Internal or External operation
• Frequency range 0.1 Hz to 10 Mhz
•Sensitivity ,;; 20 m V rms 10 MHz
• 6 digit LED display
GFG-8017G 10004
► Sweep
$455.00
Function , 2 MHz Function Generator
Special Functions Sweep Generator Operation
• Auto or Manual sweep ing
• Sweep width is 1000:1 ratio
• Sweep time is variable from 0.5s to 30s
• Sweep modes UN, LOG (Hi/Lo)
1
$626.00
2 MHz Funct ion Generator
Special Functions 3 units in 1
• Inbuilt Frequency Counter, same as GFG- 8016G
• Inbuilt Sweep Generator, same as GFG-8017G
• AM and FM Modulation, internal or external
GFG-8020G 10003
► Digital
$452.00
Readout 2 MHz Function Generator
Special functions large 0.5 inch, 4 digit LED display for
frequency indication .
'OC POWER SUPPLIES
Low ripple noise components, typically 0.5 mV rms to
1 mV ms. Excellent line and load regulation, typically
0.01 %. Dual and Quad output suppl ies with SERIES
and PARALLEL functions.
Guaranteed for 12 months, with 9 years experience in
Australia.
I
GPS & GPR-DIGITAL SERIES
► SINGLE
Output, DC Supplies
I
GPC-DIGITAL SERIES
► TRIPLE Output DC Supplies
► two
Cat. No.
Model
Panel
Width
Panel
Height
Box
Width
Box
Height
Box
Depth
UNIT
PRICE
80308
80309
80310
80311
80312
80313
80314
80315
80316
80317
80318
4U-10
2U-12
4U-12
3U-14
4U-14
AL-2U-12
AL-3U-14
AL-4U-12
AL-2U -10
AL-3U -10
AL-4U-10
19.00
19.00
19.00
19 .. 00
19.00
19.00
19.00
19.00
19.00
19.00
19.00
7.00
3.50
7.. 00
5.25
7.00
3.50
5.25
7.00
3.50
5.25
7.00
16.50
16.50
16.50
16.50
16.50
16.50
16.50
16.50
16.50
16.50
16.50
6.75
3.25
6.75
5.00
6.75
3.25
5.00
6.75
3.25
5.00
6.75
10.00
12.00
12.00
14.00
14.00
12.00
14.00
12.00
10.00
10.00
10.00
$45.00
$45.00
$52.00
$56.00
$65.00
$82.00
$92 .00
$92.00
$72 .00
$77.00
$82.00
BLACK RACK FRONT PANELS
Height
Width
Cat. No. Model
80416
80417
80418
► Two 3½ Digit LCD Panel Meter, V or A
The GPR-D Series includes Floating Output, allowing either
side to be linked to ground. FINE and COARSE voltage
control. An inbuilt, autoranging 200V DC Digital Voltmeter
(100VA model s).
I
TopCover
,: Bottom Cover
5 Side Cover
'6 Rear Panel
Handle
Sc rew 0 M3 x O 6 x 5
'9 Screw 0 M4 x 0.7 x 12
3
GFG-8019G 10006
► Multifunction
Front Panel
:> Front Mounting Plate
I
2U
3U
4U
13¼ DIGIT DMMs
FROM <at> 74
3½ Digit LED Panel Meters
Switch selectable configurations Independent both outputs controlled separately
Dual Tracking provides Master/ Slave control voltages
Parallel doubles output current range
Series doubles output voltage range
Single Fixed Output
CAT No.
PRICE
10201
10202
10203
10204
10205
10206
10207
10208
10209
10210
10211
$282.50
$732.00
$319.00
$523 .00
$589.00
$437.00
$665.0 0
$742.50
$750.00
$714.00
$714.00
!
GW GDM-SERIES
GDM-8034 M0112
Dual Variable Outputs
13.50
16.50
18.50
3.50
5.25
7.00
19.00
19.00
19.00
UNIT
PRICE
$274.00
3½ digit LCD display.
High accuracy 0.5% .
Includes CAPACITANCE measurement range.
SPECIFICATIONS
V DC ± 199.9mVto ± 1000V; ± 0.5%
(10Mohm input impedance)
V AC ±199.9mVto 1000V; ± 1 %, 40Hzto 500Hz
A DC ± 199.9µA to ±20A; ±0.5%
A AC 199.9µAto 20A; ± 1 %, 40Hz to 500Hz
Ohm 199.9ohm to 20Mohm; ± 0. 75%, 6 ranges
Capacitance 2nFto 20µF, ± 0. 75%, 1 pF maximum
resolution
Diode Test Function
Audibility Continuity Check
GDM-8135G M0113
3½ digit LED display.
All ranges are fully protected .
Wide measurement ranges up to 1.2kV and 20A.
High resolution extending to 100µVand 100 ± A.
Basic accuracy of 0.1 % .
CASE HANDLES
Cat. No. Model
80501
80502
80503
2U
3U
4U
PRICE
(PAIR)
6.50
7.50
8.50
SPECiFICATIONS
V DC ± 199.9mVto ±1000V; ±0.1 %
(10Mohm input impedance)
V AC 199.9mVto 1000V; ±0.5%, 40Hz to 10kHz
(40kHz, ± 5%)
A DC ± 199.9µA to20A; ±0.2%
A AC 199.9µAto 20A; ±0.5%, 40Hz to 10kHz
(20kHz, ± 1 %)
Ohm 199.9ohm to 20Mohm; ± 0.2 % , 6 ranges
Diode Test Function
'
Audibility Continuity Check
!ESCORT
s31& 1
SPACE SAVER SERIES
EDM-2116 M0114
$316.00
3½ digit LCD display.
Fully portable BATTERY or MAINS operation.
Includes CAPACITANCE measurement range.
SPECIFICATI ONS
$393.00
V DC ± 200mVto ±1 000V; ±0.5%
(10Mohm input impedance)
V AC 200mVto 1000V; ± 1 %, 45Hz to 500Hz
A DC ± 200µAto ±20A; ± 1%
A AC 200µA to 20A; ± 1.5%, 45Hz to 500Hz
Ohm 200ohm to 20Mohm; ± 0. 75%, 6 rang es
Capacitance 2nF to 20µF, ±2%, 1p F maximum resolution
>.
~
~
t!NO-V 3NO-V 3NO-V 3NO-V 3NO-V
A-ONE A-ONE A-ONE A-ONE A-O
g
•
<I
POWER SUPPLY 1
Cat. No. K0008
$17.95 1
g
This kit is a basic power supply based on the
7805 series of regulators. Two 7805 are used.
One gives a fixed 5V for TTL work. The second
shows how the regulator may be used to give
a variable voltage output. Heatsinks and box
provided. Max 1A output.
<
I
<
0I
<
OPAIIP FUNCTION
GENERATOR
Cat. No. K0118
$15.95
Cheap and easy way to generate square,
triangle and sine waves in the audio range.
Uses QUAD OPAMP IC and passive
components. A 1M log potentiometer gives
best control over the 6 Hz to 6000 Hz range
covered. Sine wave is made by wave shaping
circuit. 9V battery operation.
Cat. No. K0119
$27.95 1
One of the most important testing and
measurement tools is the Logic Probe. This
original & modern design can test both CMOS
& TTL circuits as well as detect fast pulses.
Its operation is fully described. Both visual &
audio indication of the logic states found.
Power from circuit being tested.
. OSCILLATOR BUILDING
BLOCKS
Cat. No. K0120 $12.95
This kit demonstrates the three basic
multivibrator oscillor circuits - the
monostable, the bistable and the astable.
Multivibrator circuits are everwhere in modern
electronics. You must know them. Learn them
here. Uses LED's to demonstrate each one.
MAINS LIGHT DIMMER
CIRCUIR
Cat.No.K0357 $17.95
This is a standard thyristor light dimmer
circuit. It can be used to control AC motors.
Has RF anti-noise circuit. Works better than
some commercial units on the market.
CAUTION: uses 240V mains voltage, you
must know what you are doing. Use care,
Build into box before using.
CONTINUITY TESTER &
2 YEAR FLASHER Cat. No. K0358 $10.95
NATIONAL SEMICONDUCTOR LM3909
introduces low power (under 3V) IC
applications. 2 PCB's plus 7 pages
documentation. Use the long life flasher as
an imitation car alarm. Over 2 years 1Hz
flashing with a 1.5V D cell. Continuity tester
sounds buzzer with rising pitch up to about
500 ohm.
<
Ll,a~!. Koass $30.95
Flashes a Xenon Flashtube exactly like those
found on planes signal beacons, fast photo
kiosks and discos. Vary flash rate between 1
per second and 10/ sec. Flashtube rated for
2,000,000 flashes. Uses SCR and neon tube.
CAUTION : uses 240V mains voltage. Must
use care and enclose in box.
9V BAffERY POWERED
XENON FLASHER Cat No. K0360 $35.95
Power a high voltage xenon flash tube from a
standard 9V battery. Wind your own potcore
transformer. It forms part of a modifed Hartley
ascillator which feeds a relaxation oscillator.
Modify the oscillator with an optional second
neon tube. SCR trigger. A lot of electronics in
this kit.
Many people come back from an overseas trip with audio, video or computer equipment which will only run at 11 0V. They get caught. But all is not
lost and some of this equipment will run quite happily via a 11 0V isolation
transformer. Pictured is one of a range of 11 0V isolation transformers
manufactured by Harbuch Electronics. All are based on the company's
toroidal transformers and thus
they are compact and have a
low residual hum field. Units
are available with ratings of
60VA,120VA,300VA,500VA
and 625VA. The units up to
300VA are all housed in tt:,e
same size case, measuring
125 x 75 x 185mm.
This kit uses the popular Harris/lntersil 7106
IC to show you how easy it is to use this chip.
Separate area on the PCB provided so you
may build your own digital volt meter or other
measuring devices. Full instructions and 12
pages of documentation enclosed. 9V battery
included.
This counter uses only 2 IC's and can be
used for event counting. Separate counter
unit included using Schmidt NAND gates and
debounce c.ircuits to eliminate switch noise.
Join two units to make 6 or 9 digit unit. May
cut off and relocated display. With data sheets
and instructions.
XENON FLASHTUBE STROBOSCOPIC
110V ISOLATION TRANSFORMER
gF;;;;:;:"n~4,95
I
E
Cat. No. Rating
T0301
300VA
T0302
625VA
Price
$149.50
$199.50
Call for prices of other ratings
LED DICE WITH SLOWDOWN$
23■95
FEATURE
Cat. No. K0361
FM TRANSMlffER BUG
• THE COMRADE Cat. No. K0408 $12.95
Push the button and the dice rolls. It gradually
slows and comes to stop on a value at
random. The modern way to play games that
use a dice. Excellent Kit to start electronics.
Ingenious circuit design using the 14017
decade counter and 555 timer with minimum
components. Box, 9V battery included.
The most powerful bug possible for its size,
3V supply and number of components. Based
on proven design. Uses trimcap for easy
tuning in the FM band. 50 meters within
buildings, 300 meters or more in open.
4 pages documentation & battery holder
included.
A-ONE A-ONE A-ONE A-ONE A-ONE
I
I
'
I
LIGHT ALARM
Cat. No. K0304
$9.95
Detacts the slightest light. Protect your cash
drawer, medicine cabinet or lolly jar with this
light alarm. Uses Darlington phototransistor
MEL12 & 14011. Good introduction to several
electronic building blocks especially NANO
gate operation and how to get a piezo to
sound loudly. 9V battery included.
BASIC ULTRASONIC MOVEMENT
DETECTOR
$37.95
Cat. No. K0305
■
A matched pair of ultrasonic transducers
operating at 40kHz will reliably detect
movement 3m to 5m away. Use 8V to 10V
supply for best results. Ideal to monitor door
opening and movement passed a point. Add
your own alarm circuit. Make a crystal locked
transmitter circuit for better stability.
I
ROULETIE LED
Cat. No. K0414
Ten LED's arranged in a circle. Pressing the
switch turns one LED on in turn to simulate a
roulette ball spinning in a circle. A slowdown
circuit gradually brings the ball to a stop.
Uses the versatile 14017 IC. Plug-in socket
provided so you easily change a resistor to
alter the spin speed.
STAIRWAY TO HEAV~~ No. K04
15
Cat No. K0410
$21,95
Record both speakers of your telephone
conversations. It turns on your tape recorder
when lift up the handset by detecting the
drop in phone line voltage. Note: your tape
recorder must have MIC and REMOTE
sockets, no battery needed. Educational Kit,
not for illegal use.
Cat.No.K0411
$10,95
This small but powerful circuit attaches to a
phone line & transmits the conversation into
the FM band. It uses the phone line itself as
an aerial. No battery required since it draws
its power from the phone line. Easily adjucted
to transmit outside the commercial FM band
for greater security.
FM TRANSMITIER BUG •
THE CADRE
Cat. No. 1<0412 $10,95
Uses 9V battery. Oscillator coil buiild into
circuit board. Uses trimcap to tune in FM
band. Proven design. Transmits over 500
meters in the open. You can experiment by
better aerial for greater range. Three pages of
documentation provided giving explaination
of circuit.
1•5 MINUTE MAINS
240¥ TIMER
Cat. No. K0413 $31,95
A up-to-date robust circuit for timing a mains
appliance for from 1 to 5 minutes. Has START
and RESET buttons. Uses triac, op-amp to
control switching and 555 for RESET circuit.
Excellent educational Kit. CAUTION: uses
mains power. You must know what you are
doing. Will switch to 4 Amps.
$16195
OPTO•TRIAC MUSIC•TO■LIGHT
MODULATOR
$14,95
The modern, safe way to make an electrical
connection from a low voltage circuit to a
high voltage circuit is to use an optocoupler.
The opto-triac is a further development. This
Kit takes an audio input 1.2-1.5Vand
modulates a mains light using an opto-triac &
triac.
TWO STATION INTERCOM/HARD
WIRED 11BUG"
Cat. No. K0511
FOX PHONE FM
TRANSMlfflR
I
Build your own gamer of skill. The bi-coloured
LED flashes RED & GREEN - press the switch
when it is GREEN and the Stairway of 6 LED's
starts to light up. But press it when it is RED
and you undo all your work. Kit introduces
many basic electronic concepts. Box & 9V
battery included.
Cat.No.K0510
TELEPHONE CONTROLLED TAPE
RECORDER SW
$18.95
$38,95
A simple but effective 2 station intercom.
Each unit contains its own microphone,
speaker and audio power amplifier circuit
using the LM386. Circuit may be modified to
become a hard wired bug. Power can be sent
to the remote unit. 10 meters of cable
supplied.
DIGITAL COMBINATION
$31
95
■
Cheap, versatile and adaptable combination
lock. Uses two 14013 quad D flip flops. Set
your own secret 4 digit code. Any wrong
number or wrong key-in sequence results the
lock. Separate touchpad PCB, 3 cable,
connectors & 12V relay included. Excellent
introduction to security devices.
LOCK
TOUCH SWITCH &
TOUCH PLATE
Cat. No. K0306
Cat. No. K0307
$13,95
Both touch switch and touch plate are built
into the same kit'. A battery can operate the
touch switch. But a mains power supply must
be used for the touch plate to operate. Uses
the 14011. A 12V relay rated to switch 240V/3A
included.
SOUND ACTIVATED TAPE
RECORDER SWITCHCat. No. K0409 $21.95
Plugs into REMOTE jack of tape recorder.
Turns tape recorder on when it detec ts a
preselected level of sound. Very sensitive.
Once the sound goes away circuit will turn off
after a short delay. Uses CMOS 74HC14.
Note: Kit does not improve sensitivity of tape
recorder itself.
~
FIBRE OPTIC AUDIO
LINK
Cat. No. K0512 $79,95
Complete Kit to m~_ke an audio link using
light guided by 1mm plastic fibre optic cable.
14 feet cable, microphone, speaker supplied.
Kit will send signal in over 500 ft of optic
cable. 2 PCB. Each requires 9V battery. Uses
matched LED emitter/detector from Motolora.
Very simple to use.
LM386 LOW VOLTAGE AUDIO
AMPLIFIER MODUL~at. No. K0611 $11.95
A Kit module designed to be used as a
building block in a larger project. The National
Semiconductor LM386 is a general purpose
power amplifier designed for use in low
voltage applications. Gain may be set
between 20 and 200. Used in Kit Cat. No.
K0511. LM386 Data Sheet included .
TDA70521WPOWER
AMPLIFIER
Cat.No.K0611
$12,95
A 1W power amplifier module designed to be
used as a part of a larger project. The Phillips
TDA7052 is a general purpose 1Wamplifier
ideal for low power battery operations from 3
to 15V. Very few external components
required. No heatsink needed. Short circuit
protected. Uses 8 ohm speaker.
2
A-ONE~
ELECTRONICS PTY LTD
432-434 Kent Street,
Sydney NSW 2000.
Phone: (02) 267 4819.
Fax: (02) 267 4821.
A C.N. 003 882 513.
MAIL ORDERS WELCOME:
CHEQUE, MONEY ORDER,
AMERICAN EXPRESS,
BANKCARD,MASTERCARD
AND VISA.
POSTAL CHARGE
$5-$25 ...... $4.50 $51 -$100 ....... $7.00
$26-$50 .... $5.50 Over $100 .... $10.00
Phone or write to us for a copy of your
price list. Shop hours Mon-Fri 9-5.
Sat 9- 1. All prices include sales tax.
------------------------------------------------------'
>.
~~
:flNO·V :flNO-V :flNO-V :flNO-V :flNO ·¥
SERVICEMAN'S LOG
A story to support Murphy's Law
Traditionally, by Murphy's Law, any servicing
short cuts we attempt will always bypass the
fault. And conversely, when we find a fault by
conventional means, we can see an obvious
short cut. But let's not take Murphy too
seriously.
The truth is, we live on short cuts
of one form or another, from recognising the symptoms from previous jobs
to the replacement of complete boards
in order to save time. Generally, these
short cuts work. It is only when they
don't work that we blame Murphy (or
bad luck).
.
This story would seem to support
Murphy's Law, at least initially. It concerns a Thorn Model 9007 colour TV
set, which uses the Mitsubishi G series chassis. This chassis was also
marketed as the AWA model C608.
These sets are now about 15 years old
and this one belongs to a local motel,
the owner being a relatively new customer.
The owner brought it in with the
complaint that it had lost colour and
an initial check on the bench confirmed this. However, I found that it
was possible to brute force it into
colour - of a sort - by deliberately
mistuning in the direction of the
sound carrier with the colour saturation control wound full up.
I used the term "colour - of a sort"
because there was something funny
about it; that being the only way I
could describe it initially. To put it a
little more scientifically, I knew it
wasn't right but couldn't work out
what was wrong with it visually.
But there was more wrong with the
set than that. The first thing I noticed,
apart from the loss of colour, was that
the picture was grossly over-scanning;
mainly horizontally but also vertically
to a somewhat lesser degree. There
was also some obvious convergence
error.
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for better
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from weak
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signals.
Peter C. Lacey Services Pty. Ltd.
P.O. Box 678 (74Fulton Rd.) Mount Eliza 3930
T el:03 787 2077 Fax: 03) 787 3460 ACN006893438
64
SILICON CHIP
Colour bar pattern
I fed in a colour bar signal from a
TV pattern generator and, by careful
mistuning, was able to bring this up
in colour. But the degree of mistuning
was very critical and it produced a
strange effect. While each colour bar
displayed the correct colour, it did so
for only part of its width, starting
with monochrome on the left- hand
side and graduating to colour on the
right. This probably accounted for the
"funny" effect I had observed on program material.
.
My first reaction to the colour problem was to speculate on a possible
front-end fault. Perhaps the tuner or
the IF system was upsetting the response curve. However, I put these
thoughts aside for the moment and
decided to investigate the overscan
problem.
HT voltage
The first thing I check in such cases
is the HT rail voltage and this paid
off. Normally, the HT for this set is
105V but it was actually sitting on
138V. This was far too high and suggested a fault in the power supply
regulator system.
This set is made up of a main board
("PCB-MAIN") and a number of auxiliary boards which plug into this via
edge connectors. Fortunately, this being an old set, I have accumulated a
fair stock of these auxiliary boards
from scrapped sets and these prove
very useful. First, they can help pinpoint a faulty board quite quickly by
simple substitution. Second, leaving
the substitute board in place is often
the quickest and cheapest solution;
an important factor in sets of this age.
So I simply fished out a spare "PCBPOWER REG" board and plugged it
into the main board. That didn't help
much because the HT voltage was
virtually identical. This made me suspect that one or both of the power
~~?sr,
i"RA't>l1IONAU-'-f, 'B'-f MURPHY'S LAW,
A~Y SE"R.V\CIN6 SHO'R.T"CUTS W~
A1TE:M?r W\U... At..WAVS "BVPASS
™e:.
FAuL--r.. o
regulator transistors , Q901 and Q902
(2SC935), might be leaky. These are
mounted off the board, via a plug and
socket connection.
The plug and socket arrangement
makes it easy to check them but I
could find nothing wrong. I replaced
the original power board and went to
the "B-ADJ" pot, VR901, to see if (1) it
was still working and (2) whether there
was adequate adjustment available.
Well, it was working and I had no
trouble resetting the HT to the correct
105V with a perfectly reasonable pot
setting. In short, all the indications
were that there was nothing wrong
with the power supply, except that
the pot had been incorrectly set. Why
this was so was a mystery at that
point. And why hadn't the replacement board clarified the problem? It
turned out that, for some reason, now
lost in history, it was also wrongly set.
In fact, I put it back in the set and was
able to reset it to 105V as well.
So that cured the gross overscan
and a minor touch up with the appropriate controls produced a well proportioned picture. But we still had
the colour problem. In fact, it was
now worse than ever, in the sense that
it was much harder to brute force than
before (a lesson there, had I but realised it).
The next logical board to check was
the chroma board, "PCB-CHROMA". I
have several on hand and it is a simple un-plug, plug-in operation. But
no joy. Remembering how I had been
caught with a faulty substitute power
board, I tried a second one. But it was
no use; this was not the source of the
trouble.
So what next? Still convinced that
the best approach, at least initially,
was board substitution, I picked what
seemed the next logical one - the
"PCB-VIDEO-CHROMA-OUT" board.
Again, it was a simple operation, or at
least it would have been ifl'd had one
in stock. I didn't as it turned out and I
finished up borrowing one-from a colleague.
Unfortunately, the effort was wasted; there was no joy here either. And
that just about exhausted the board
swapping approach. All the major and
likely sub-boards had been changed,
without result. The two suspect areas
remaining were the main board and
the tuner.
Swapping the main board was
hardly a proposition, at least at this
stage, but I had considered the possi-
bility of a tuner problem causing a
faulty response curve. Fortunately, I
am well set-up to check tuner problems. As mentioned in my last set of
notes, I have a self-contained tuner ·
and power supply which makes an
ideal substitute in such situations. It's
an old turret type VHF tuner from the
monochrome era but it still works perfectly.
The substitution was simple. The
set's own VHF tuner connects to the
IF system, the "PCB-HF" board, via
pin 1 of a 4-pin plug (FA). I simply
pulled the plug off and clipped the
substitute tuner output lead to pin 1.
And that disposed of that theory
quick smart! There was absolutely no
change in the set's behaviour. And it
also put paid to the idea of a simple
fix by substitution. I was going to
have to start working now and track
down the fault the hard way.
So, harking back to my opening
paragraphs, had my short cut attempts
been a waste of time? Not at all; they
had ruled out a very large part of the
set, involving hundreds of components, and forced me to narrow my
investigation to relatively few components.
That said, I wasn't quite sure where
to go from there. The only thing I
could immediately think of was the
colour burst and/or the associated
gating pulse. It was a long shot, because failure here normally means
total loss of colour. However, the CRO
quickly ruled out that theory, as everything was normal here.
What next?
So what hadn't I checked? Perhaps
I had missed something around the
chroma board area and I so I began by
checking the supply voltage. The supply to this board is a nominal 20V
which is derived from the deflection
out board ("PCB-DEFL-OUT") and fed
in on pins 1 & 10.
This voltage was spot on but I then
began wondering about any bypass
capacitors associated with this supply. ThE;lre is one on the chroma board
(pin 10) but this was ruled out because the board had been changed.
Further checks revealed a second bypass capacitor (C579) on the deflection out board, at point "B5". But
again I drew a blank as changing it
made no difference.
I was feeling rather frustrated by
now. In desperation, I went over the
FEBRUARY
1993
65
a problem. It looked like I would need
access to the control board but this,
not to put too fine a point on it, is a
swine of a thing to remove. What was
needed was some other way to conFig.1: the faulty circuit
firm my theory before I took such a
section in the Thom 9007
colour TV set. Transistors
drastic step.
Q623 & Q624 are the first &
So I tried another tack. By suitably
second chroma amplifier
juggling the chassis, I was able to reach
stages respectively, while
the underside of the main board and
VR671 (top) is the colour
bridge pins 15 & 16 of the edge consaturation control. This pot
nector using a clip lead. This was
connects to the chroma
electrically equivalent to turning the
board via a plug connector
saturation control fully up which,
to the main board (labelled
mechanically, was where it had al"MN") & then via pins 15 &
ready been set.
15 of an edge connector
The result was that the picture imsocket.
mediately jumped to full colour saturation. Not only that, but all symptoms of the fault had vanished. I could
now bring in colour - albeit oversaturated - on all channels, without
resorting to the critical tuning procedure previously required.
So at last we had a breakthrough; it
physical arrangement. The
appropriate part of the cir- was somewhere in the saturation con•ce-•ow~ocus (
cuit is reproduced here as trol circuit. But where? It took only a
,
~
I._
Fig.1. The saturation con- moment to shift the clip lead from
trol is a soon pot, VR671, pins 15 & 16 on the edge connector to
which connects to four pins pins 2 & 4 on the main board, whereon the control board. Pins 1 upon the fault was back exactly as
and 3 connect to chassis, before.
pin 2 to the moving arm,
So what was there between the two
and pin 4 to the active end set of pins? Answer: just two copper
of the pot. Plug MN fits on tracks, about 70mm long, and the solthese pins and its cable ter- dered joints to them. I went over all
minates on a second MN these joints but could find nothing
plug which mates with four wrong. Just to make sure, I resoldered
~~i
pins on the main board.
them anyway but I wasn't really surWith me so far? Right.
prised when this had no effect.
The saturation control is
But I was hot on the trail now. By
eventually wired into the pulling the plug off the motherboard
chroma amplifier chain pins, I was able to make a resistance
aroµnd transistors Q624 measurement from pin 4 to pin 16.
and Q625. This is achieved There was no problem there but pin 2
chroma circuit again but without re- by wiring pins 2 and 4 on the main to pin 15 was another story - this
sult. Eventually, I finished up near board to pins 15 and 16 of an edge · measured no less than 100!2 And,
the top lefthand corner of the chroma connector and this, in turn, carries seeing that I had already cleared the
circuit, looking at a 4-pin plug on the the chroma board. Pins 1 and 3 con- soldered joints, this left a faulty copnect to chassis via the main board.
per track as the only possibility.
main board marked "MN".
I had traced out all this circuitry
Yet try as I might, I could see nothThis plug connects to the colour
saturation control which, along with because I wondered whether the fault ing wrong with it, even with a magnithe contrast, brightness, vertical hold was somewhere in the saturation con- fying glass. Granted, the green lacand horizontal hold controls, is trol circuit. Ifit was, there were plenty quer covering the print didn't help
mounted on a sub-board designated of places where it could occur: either and, in any case, I was well past car"PCB-CONTROL". It sits at the front of in the pot itself, in the plugs, between ing about the fine detail. All I wanted
the set, beneath the picture tube, and the chroma board and the edge con- was to get the job finished.
It was simple enough, of course. A
the controls are all connected to the nector, or in the soldered connections
appropriate parts of the circuit via to the boards.
short length of tinned copper wire
plugs, sockets and cables.
between the two pins effectively
In order to follow what happened Pure speculation
wiped out the offending resistance
next, it is important to get a clear
The trouble was, this was all pure for all time. I then put everything
picture of both the circuit and the speculation and proving it presented back together again, satisfied that the
SERVICEMAN'S LOG - CTD
r
66
SILICON CHIP
_____
fault had been positively identif.ied
and fixed.
Why was the HT high?
And that, as far as the job itself was
concerned, was that. But there is a
little more to the story than just the
colour fault. What was the history of
the fault and why had I found the HT
rail wound up to 138V?
As I mentioned at the beginning,
this motel is a relatively new customer and this was the first time I had
seen this particular set. Prior to that,
the motel had employed a serviceman from an adjacent suburb. I know
the party concerned. He's a nice
enough bloke at a social level and, I
have no doubt, is very kind to his
mother.
But his technical expertise is another matter. In short, I don't have a
very high regard for it.
So what happened? I can only
speculate, of course, but I think it
went something like this. The board
was probably cracked right from the
start but functioned OK while the two
edges of the copper track were bright
and touching. But eventually the copper corroded and this introduced
It had him beaten until he discovered,
TETIA TV TIP
Panasonic NV-G22A VCR
(G mechanism)
Symptom: machine won't accept
cassette. Capstan motor runs
backwards and forwards for 1015 seconds, then machine
switches off. If fault occurs while
tape is loaded, machine will not
eject.
Cure: Check for "cut washer" clip
on shaft under centre pulley. The
pulley contains a spring loaded
clutch which has a tendency to
push the clip off the shaft.
TETIA TV Tip is supplied by the
Tasmanian branch of the Electronic Technician's Institute ofAustralia. Contact Jim Lawler, 16
Adina St, Gei/ston Bay 7015.
More on computers
enough resistance to upset the colour
to some extent, at least on an intermittent basis.
It was too much for our serviceman
friend, although I would be the first to
concede that it was a very nasty fault.
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probably by accident, that he could
cure it by jacking up the HT. So that
was what he did, hoping that the resultant overscan would go unnoticed
- which it did.
Eventually, of course, the corrosion
increased and the fault re-appeared,
intermittently at first, then permanently. And that's where I came in.
Am I being too hard? I don't think
so. I would be the first to agree that
anyone can be stumped by a stinker
and I'm not criticising on that basis.
But faking a cure is another matter.
Apart from the fact that the customer
is being cheated, it simply doesn't
pay off in a purely business sense.
Sooner or later it backfires and the
customer forms his own conclusions.
Anyway, I've scored a satisfied cus. tamer.
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After my two previous stories about
servicing computer monitors, I imagined that that would be the end of it;
that I could go back to doing fair
dinkum service work. But it was not
to be; someone blabbed about my
monitor repairs and before long I had
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EMONA
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NSW ......................... (02) 519 3933
VIC ............................ (03) 889 0427
QLD .......................... (07) 397 7427
DISTRIBUTORS
Perth ........................ ..... (09) 244 2777
Adelaide
....... (08) 362 7548
Hobart
......... (002) 34 2233
FEBR{!ARY
1993
67
SERVICEMAN'S LOG - CTD
~
c::=:::::::,
~ c:>C::::.~
another customer appealing for help
with a suspect monitor.
It turned out to be another Acer
MM211 - a fact which made me feel
almost cocky about tackling it. After
all, I now knew where all the screws
were. On the other hand, it seemed to
be tempting fate to hope that it would
be another power supply fault. '
Even so, the symptoms as related
by the customer seemed to support
that theory. The fault had first appeared as a collapsed vertical scan,
resulting in a bright horizontal line
across the middle of the screen. It had
lasted only a second or so, the monitor then reverting to a normal display.
In fact, the customer at that time
wasn't even sure whether there was a
fault or whether he had simply observed a brief mains power failure.
When the fault subsequently reoccurred several more times, he knew
he had a problem. On the other hand,
he wasn't sure what to do about it. He
knew enough about intermittent faults
68
SILICON CHIP
to realise that tracking them down
could take days, or even weeks. And
as he was using the computer professionally, he couldn't afford to have it
out of action for a long period.
So he kept flogging it along while
ever it would go until, inevitably, it
failed completely. And that was the
best thing that could have happened
really. At least ·I had something to
work on.
With the cover removed, I went
straight to the 12V rail where it
emerges from the 12Vregulator. It was
dead, so I moved back to the input
and measured 20V which, from my
previous experience, was spot on.
Crook regulator
My immediate conclusion was that
the regulator had packed it in but I
checked the 12V rail for shorts, just to
be sure. There was nothing wrong
there, which left only the regulator.
This was mounted on a 75mm-long
finned heatsink which is attached to
the PC board by a couple of screws
tapped into one end. The regulator IC
was mounted near the bottom of this
heatsink, with its three leads passing
through holes in the board to the copper pattern on the underside.
The first problem was to identify
the IC. I can't remember the type
number but it was a new one on me
and so I sought the help of the friendly
man behind the counter at the local
Dick Smith Electronics store. It turned
out that he was quite familiar with
the unit and the circuit but not with
the regulator IC. No problem, though.
A quick phone call to the service department at headquarters and he had
the answer. The original type number
was not available but it could be replaced by a 7812. This is a regular
stock item and he pushed one across
the counter.
I expected that that would virtually
be the end of the story, the repair
involving no more than a routine replacement. But not quite. Not being
familiar with the faulty IC, I took the
precaution of tracing the copper pattern around the pin connections before I removed it.
And just as well. Having identified
the pin connections, I compared them
with the 7812 arrangement and found,
as I feared, that they were not the
same; two of the pin connections were
transposed.
This was an annoying development
because it meant a messy repair. The
IC would have to adopt a crossed leg
attitude and I would probably have to
attach an extension lead to one leg to
facilitate this.
I was trying to figure out how best
to do this when I noticed an extra set
of unused holes adjacent to those for
the existing regulator but which had
no apparent purpose. When I traced
the copper pattern around these holes,
it quickly confirmed what I had begun to hope. The makers had anticipated this situation and had provided
a second set of connections to suit the
alternative pin arrangement.
From there on, it was plain sailing.
I mounted the IC on the heatsink,
soldered its leads to the alternative
pads, and put everything back together
again. And, of course, it worked and I
had another happy customer.
But I swore him to secrecy. I don't
want any more computer monitors,
thank you. And they're making them
in colour now, aren't they? Ouch! SC
:AR
:AR
:AR
:AR
]!~
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ELEC
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Stock is limited, there may not be all items in all stores. If your nearest Jaycar Showroom has sold out of the item
you want to purchase, you can phone -(02) 743 6144 and they will advise which stores had that particular
product in stock at the beginning of the sale. You can also phone around yourself, or you can place an order with
our Mail Order Department on (02) 743 6144, using a credit card and we will do the finding for you and send
you the goods (plus post and packing). For full specifications and descriptions on the products listed below check
our 1992 catalogue. Be quick, stock is limited and won't last.
Description
WAS
Answering machine/data
$1.95
Cassette 60 min
12 cassette carry case
$2.50
TV lightweight headphones
$9.95
Aviation headset series II
$189.00
Push to talk switch for above
$29.95
8 ohm 5 watt oval speaker
$4.95
6" black metal speaker grille
$6.95
CB microphone with lead
$24.95
Microphone wired/wireless
$45.95
Microphone electret/
$29.95
unidirectional
Philips stereo microphone
$29.95
22mm microphone wind shield $2.50
BNC - PL259 video cable 1.8m $3.95
PL259 - PL259 video cable 1.8m $2.95
PL259 - RCA video cable 1.8m $2.95
IC OP-amp cookbook
$39.95
CMOS cookbook
$44.95
TTL cookbook
$44.95
IBM personal upgrade
$44.95
guidebook
Practical digital elect handbook $19.95
Synthesisers for musicians book $19.95
Electronics build and learn book $17.95
Introduction to digital audio book$17.95
How to set up home recording $17.95
studio book
Home security electronic
$19.95
projects book
MS DOS/PC DOS quick
$12.95
reference book
386 computer handbook
$19.95
1-2-3 for Windows 1st step book $22.95
WordPerfect for Windows book $22.95
Understanding digital
$12.95
troubleshooting book
24 SCR projects book
$14.95
Understanding automation
$12.95
systems book
Understanding computer
$12.95
science book
Relay and their applications book $9.95
51 projects using CD4011
$3.95
IC book
Fascinating IC's book
$3.95
DigitallC's book
$7.95
150 circuits book
$9.95
Simple electronics
$3.95
experiment book
Electronic hobby circuits book $3.95
Simple audio projects book
$3.95
Practical audio visual
$3.95
projects book
Semiconductor diodes book
$2.95
Practical electronic games book $3.95
Learn by experimenting CMOS $7.95
IC's book
Build your own test
$4.95
instruments book
Practical electronic projects book$3.95
Practical OP amp pro1·ects book $7.95
Electronic gadgets for you book $3.95
Exciting electronics
$3.95
experiment book
Using function generators
$7.95
and PLLS book
NOW
$1.50
$2.00
$5.95
$150.00
$20.00
$3.50
$5.00
$18.00
$32.95
$23.95
$19.95
$1.50
$2.00
$1.50
$2.00
$29.95
$34.95
$34.95
$34.95
$7.95
$12.95
$7.95
$12.95
$12.95
$12.95
$9.95
$14.95
$15.95
$15.95
$9.95
$9.95
$9.95
$8.95
$6.95
$2.95
$2.95
$4 .95
$5.95
$2.50
$2.50
$2.50
$2.50
Cat. No. Description
WAS
BM-2460 Electronic science
$3.95
experiments book
BM-2461 Understanding & using
$3.95
mu ltimeters book
BM-2462 Practical electron ic devices book $3.95
BM-2463 Electronic projects for the
$3.95
car book
BM-2467 Build your own intercoms book $4.95
BM-2468 Versatile electronic circuits book $7.95
BM-2475 Teach yourself DOS
$19.95
3.3 & 4.0 book
BM-2476 Encyclopedia of
$34.95
electronic circuits
BM-2480 Thyristor theory app book
$12.95
BM-2452 Practical electronic games book $3.95
BM-4556 Inter'! OP amp & Linear IC select $22.95
BM-4558 Inter'! digitallC selector book
$14.95
BM-4560 Inter'! diode & SRC index book $24.95
BM-4564 Inter'! microprocessor selector $8.95
CM-2084 Med horn midrange 30W speaker$32.95
CW-2152 10" subwoofer 120W rms
$129.50
CS-2480 Studio 3-55L speaker kit
$279.00
CX-2610 Minstrel 2 way crossover
$29.50
DC-3080 CB quick disconnect ant fitting $13.95
DC-3084 CB lighttension spring 5/16"
$12.95
DC-3087 CB mic clip magnetic
$2.95
DC-4000 Cellular car phone antenna
$49.95
HP-0415 3mm x 25mm R/H bolt pkl 200 $5.95
HP-0419 3mm x 32mm R/H bolt pkt 200 $7.50
HP-0451 4mm x 10mm R/H bolt pkl 200 $6.50
HP-0466 4mm washer flat pkt 200
$5.50
HP-0506 4mm x 12mm C/H bolt pkl 20
$2.95
HP-0622 No6x15mm black spkr
$22.95
screw pkl 200
HP-0626 No10 x 30mm black spkr
$27.50
screw pkl 200
HP-1177 8mm cable clips pkl 100
$7.95
HB-5480 Alarm control panel box metal $24.95
HB-5935 Vero box
$28.95
205(w) x 140(d) x 110(h)mm
HB-5948 Black plugpack type box
$2.95
HB-6051 Sml quality box
$15.95
160(I)x80(w)x44(h)mm
HB-6052 Med quality box
$16.95
160(1) x 80(w)x60(h)mm
HB-6056 Lge quality box
$21.95
197(I)x110(w)x86(h)mm
HB-6250 Waterproof box
$19.95
150(I)x110(w)x70(h)mm
HH-8510 1 x T03 heatsink 50x50x25mm $2.95
HG-9901 Copper tape .031 " EZC300311
$5.65
HG-9902 Copper tape .05" EZ300501
$5.65
HG-9909 14 DIL pattern EZ6014
$5.95
HG-9910 16 DIL pattern large EZ6004
$7.25
HG-9918 14 DIL pattern small EZ6013
$7.25
HG-9919 16 DIL pattern large EZ6453
$7.25
HG-9920 40 DIL pattern large EZ6987
$7.25
HG-9931 Tape .031 " 20yd EZ3004
$5.50
HG-9934 Tape .062" 20yd EZC3010
$5.50
HG-9935 Tape .080" 20yd EZC3012
$5.50
HG-9938 Tape .125" 20yd EZC3018
$5.60
HG-9939 Tape .200" 20yd EZC3020
$5.60
HG-9945 Pad 156"0D x 0.031" ID EZD103 $5.60
HG-9948 Pad 250"00 x 0.062" ID EZD109 $5.60
HG-9991 Scotchcal plastic black/white
$11.95
KA-1390 Kit - 50MHz freq enter EA12/91 $169.50
KA-1598 Kit - 40 watt inverter EA8/85
$99.50
KA-1610 Kit - 300 watt inverter EA9/85
$269.00
NOW
$2.50
Cat. No.
KA-1696
KA-1699
$2.50
$2.50
$2.50
$2.95
$4.95
$14.95
KA-1724
KA-1728
KA-1729
KA-1731
KM-3044
KC-5052
KC-5075
$26.95
KC-5076
$9.95
$2.50
$17.95
$6.95
$19.95
$6.95
$19.95
$99.00
$229.00
$22.95
$8.95
$7.95
$1.00
$34.95
$3.95
$4.95
$4.50
$3.50
$1.00
$14.95
$19.95
$3.95
$16.95
$19.95
$1.95
$11.95
$12.95
$16.95
$9.95
$2.00
$3.95
$3.95
$3.95
$4.95
$4.95
$3.95
$3.95
$3.50
$3.25
$3.25
$3.25
$3.25
$3.25
$3.25
$8.95
$139.00
$75.00
$199.00
KC-5077
KC-5082
KC-5085
KC-5088
KC-5096
KC-5100
KC-5111
KC-5114
LF-1260
LT-3180
LM-3846
LM-3850
LA-5012
LA-5018
LA-5020
LA-5022
LA-5023
LA-5065
LA-5160
LA-5187
LA-5270
LA-5272
LR-8850
LA-8922
MB-3520
MS-4004
MT-4710
MT-4720
Ml-5000
ME-6000
ME-6002
ME-6010
NA-1030
NA-1032
NC-4266
PS-0186
PP-0247
PS-0355
PS-0357
PS-0358
PP-0412
PP-0414
PS-0619
PP-0670
PS-0672
PP-0685
PS-0688
PP-0861
PS-0895
PS-0896
Description
WAS
Kit - Temp probe multi meters
$19.95
Kit- Bench amp/signal
$44.95
tracer EA4/88
Kit-Voltup 1.5V- 9VDC EA 5/90 $19.95
Kit-VHF powermatch
$52.50
Mk2 EA9/90
Kit - RF probe - suit 1728 EA9/90 $7.50
Kit - Trans/FET tester EA10/90 $32.00
Kit- 6000 Mosfet mod AEM7/86 $149.95
Kit - Touch lamp dimmer SC6/89 $34.95
Kit - Capacitance meter
$109.00
1pF-9999µF SC5/90
Kit - Reluctor high energy
$46.95
ignition SC5/90
Kit- Universal stereo
$24.95
preamp SC6/90
Kit - DC offset for DMM SC8/90 $34.95
Kit- Dimmer discolight SC10/90 $39.95
Kit - Fruit machine SC1/91
$24.95
Kit-4 channel lighting desk
$329.00
Kit-Talking voltmeter SC10/91 $42.95
Kit - Telephone call timer SC3/92 $29.95
Kit - VHF TV transmitter SC3/92 $89.50
Pot core FX2243 pair
$14.95
Outdoor UHF band 4 & 5 antenna$39.95
RF modulator
$3.95
Audio/video modulator UHF
$34.95
PIR doorway mini alarm
$49.95
Pulse count PIR detector
$79.00
Hall lens for above
$5.95
PIR intelligent pulse count det $99.00
Hall lens for above
$5.95
Glass shatter detector
$9.95
Alarm digital access keypad
$69.95
4 sector expan board Scope 6/30 $45.00
Life guard vapour detector
$39.95
GUM-50 life guard vap detector $24.95
4 door centrallocking kit
$119.50
Moss hyper car interior detector $99.50
12 volt 4 amp car battery charger$44.95
IEC mains filter 3 amp
$9.95
Balanced microphone
$37.50
transformer 200/50k
Mic line-line transformer 1Ok-10k$37.50
Inverter 12VDC to 240VAC 300W $399.00
Universal electric fence
$129.50
Earth stake to suit above
$14.95
High efficiency electric fence
$139.50
Screen care spray$7.50
monitor cleaner
Compuclean spray$10.95
computer cleaner
PCB etch resist ER-71
$14.95
6.5mm stereo chassis ski
$2.25
RCA plug metal - solderless
$1.95
6 pin DIN line ski
$1.20
7 pin DIN chassis ski
$1.85
8 pin DIN line ski
$1.95
2mm plug for multimeters red $0.90
2mm plug for multimeters black $0.90
Rapid wire solderless coupler
$3.50
Twinax coax metal plug
$9.95
Twinax coax chassis ski
$11.95
PL259 rapid plug solderless
$3.50
S0-239 bulkhead ski round
$2.25
D37 male PC mount connector $2.95
Centronics socket
$4.95
Centronics IDC line socket
$6.95
NOW
$12.95
$39.95
$12.95
$39.95
$3.95
$24.95
$109.00
$27.95
$85.00
$29.95
$19.95
$18.50
$29.95
$14.95
$269.00
$29.95
$19.95
$69.50
$7.95
$29.95
$2.95
$24.95
$34.95
$55.00
$2.95
$79.00
$2.95
$4.95
$49.95
$19.95
$14.95
$10.00
$89.00
$65.00
$34.95
$7.95
$29.95
$29.95
$295.00
$89.50
$8.95
$99.50
$5.50
$6.95
$3.95
$1.00
$1.00
$0.60
$0.80
$0.80
$0.40
$0.40
$1.50
$5.00
$5.00
$1.50
$1.00
$0.20
$2.50
$2.95
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V
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No postage stamp required in Australia
FEBRUARY
1993
73
I
PRODUCT SHOWCASE
I
100 watt audio
amplifier module
Although this amplifier module
from A-One Electronics is labelled as
a "lO0W pure class A main amplifier", it is technically a class AB amplifier judging from the size of the
heatsink and the fact that it has a
single 2A fuse.
In fact, the circuit information gives
details of how to set up the quiescent
current. The resultant current of 600
milliamps is much higher than the
usual 50-lO0mA one would expect
for a typical class AB design and will
effectively give class A operation up
to about 1 watt RMS into an 8-ohm
load.
Recommended supply voltages
range from ±30V to ±42V although
maximum power will naturally be reduced at the lower voltages. A suggested layout of two modules in a
stereo amplifier has fan cooling which
would be mandatory in view of the
standing dissipation ofup to 48 watts
in each channel.
The module is well made and has a
complementary differential amplifier
in the input circuit and MS15003/4s
as complementary common emitter
Digital recorder/
announcer
Kingray video
combiner amplifier
This very handy device is
incorrectly named which
must cause a lot of confusion
to potential buyers. It does not
amplify or combine video signals. What it does do is combine the signal from a VHFI
UHF antenna with the modulated RF output signal from a VCR.
The combined signal is then amplified and fed to a 4-way splitter.
Tlie effective gain at each of the
four outputs is +6dB, referred to
the antenna input.
If it was correctly named, it
would perhaps be called a "VHF/
UHF/VCR combinei-/splitter"
which is still a mouthful and possibly just as confusing to the
uninitiated. What the Kingray
SA214V does do is enable you to
watch off-air programs or tapes
from your VCR on four TV sets in
74
SILICON CHIP
stages (ie, not emitter followers) in
the output circuit.
The 100W module(CatS0313) is
available for $79 from A-One Electronics Pty Ltd, 432-434 Kent Street,
Sydney 2000. Phone (02) 267 4819.
your household. It is powered from
a 9V DC plugpack which is connected to one of the 75-ohm output sockets via their PSK0l power
adaptor. This is supplied together
with the 9V plugpack.
As such, the SA214V is a very
useful accessory and one which
will find use in many households
with more than one TV set. We're
pleased to report that the SA214V
is manufactured in Australia and
appears to be very well made.
The unit is available from David
Reid Electronics at $99.95.
The MOH330A digital recorder announcer from Eletech uses CVSD compression to provide good quality audio record/play from a compact desktop machine. Originally designed to
replace on-hold signal devices such
as tape recorders and radio sets, the
MOH330A recorder has many other
applications. Due to its solid state
design with no moving parts the unit
is ultra reliable.
Good quality speech or music can
be recorded on the device using a
microphone or the line input. A VU
meter displays the record and playback levels. One or
two messages can be stored with lengths of up to four
minutes and eight seconds. Connections to the unit are
via standard audio connectors or phone jacks. An external control can start the playback for use in talking signs,
security messages, fire warning systems, etc.
For further information contact Zenology Sales Pty
Ltd, 7/245 Springvale Road, Glen Waverley, Vic 3150.
Phone (03) 802 0599).
First High-Speed IEEE 488.2
Controller for Notebook PCs
New concept in handheld
logic analysers
IOtech
The "LogicBridge 136" is a new concept in logic analysers. Handheld and battery powered, the LogicBridge
performs as an intelligent 3-channel logic probe, yet is
also able to store and display waveforms like a logic
analyser. Basically it is a dedicated logic instrument for
those involved in the design, repair or maintenance of
digital electronic circuits and equipment.
Fast waveforms can be easily identified by taking a
"logical snapshot". Not only can this save hours of lab
work but with such a facility, data can be retrieved from
memories for later review and analysis.
The waveforms are viewed and measured on a high
resolution LED display which simulates binary level
signal/channel traces as displayed on a logic analyser's
CRT. The effective real time bandwidth of the Model 136
is 10MHz but the glitch catcher function allows the
capture of pulses down to 50 nanoseconds.
The unit may be operated in real time or memory
mode. Memory mode allows for the acquisition and
storage of up to 100-bit sequences. Waveforms can then
be recalled, visually or logically compared (AND, OR,
EXCLUSIVE OR) to incoming waveforms or fed to an
external source via a serial port. Up to 12 consecutive
memories (two waveforms each) can be automatically
linked together to store long data sequences.
Being a dedicated instrument, the LogicBridge 136 has
a range of useful digital debugging, signal identification
and tracing facilities. In addition, the audio output may
be used for indicating an occurence of trigger and for
The Personal488/NB is a compact external IEEE 488.2 interface that enables 170 Kbyte/s IEEE 488.22 control of up to
fourteen IEEE instruments from a notebook PC via its parallel
port.
A virtual PC plug-in board in terms of speed and performance,
the Personal488/NB is compatible with both IOtech 's DLL
driver for Microsoft Windows and with its DOS subroutinestyle and device driver software. The Personal488/NB also
supports third-party data acquisition software packages, such
as DADiSP and Labtech Notebook.
The Personal488/NB uses FPGA (field programmable gate
array) technology to permit simultaneous instrument-control
and printer transactions via its connection to a notebook PC's
parallel port. The unit can draw power from a notebook PC's
keyboard port, a 7 to 15 VDC voltage source, or a standard A/
C voltage source via an included power supply.
Portable and Remote Applications. As notebook PCs decrease in price and increase in functionality and power, many
engineers are finding them practical, easily transportable alternatives to cumbersome desktop PCs. The Personal488/NB
enables engineers to use notebook PCs in IEEE instrument
control and data acquisition. It is well suited for vehicle
testing, such as aircraft and automobile testing, where physical
space is at a premium, and is also ideal for users who require a
portable computer, such as test-instrument sales engineers,
who can now use notebook PCs to demonstrate IEEE 488
instruments on customer calls.
The Personal488/NB is also useful for engineers who need to
analyse acquired data away from the test site because it enables the same notebook PC to be used both on-site for data
acquisition, and in the Jab for subsequent data analysis. This
eliminates the time-consuming data transfer processes and
cross-platform incompatibility problems sometimes associated with using one desktop PC for testing and another for
analysis.
SCIENTIFIC DEVICES AUSTRALIA PTY LTD
~
Melbourne
Fax
Sydney
Fax
Adelaide
Fax
(03)
(03)
(02)
(02)
(08)
(08)
579
579
344
349
281
281
3622
0971
5200
2602
3788
4194
Product names listed are trademarks of their respective manufacturers' company.
FEBRUARY
1993
75
actual waveshape identification. For further information, contact Emona Instruments, PO Box K720, Haymarket, NSW 2000. Phone (02) 519 3933.
.
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Handy breadboard for small
prototype circuits
If you want to wire up a circuit with just a few
ICs these little prototyping boards are quite handy.
They have 29 columns of terminals and so you
could insert three 14-pin ICs and one 8-pin IC, or
other combinations to take up the space.
The board has double-sided foam tape on the
back so it can be conveniently mounted on a metal
plate and it also comes with a handy little pad of
wiring sheets so you can record your layouts.
All this costs just $5 .95 (Cat. P11002) from Rod
Irving Electronics, 74 Parramatta Rd, Stanmore,
NSW or interstate branches.
Solar powered musical keychain
from Rod Irving Electronics
This little keyfob is a bit
of a gimmick. When its solar cell is exposed to strong
light it plays "Somewhere
Over The Rainbow" al though we suspect that noone will be tempted to sing
along with it. More useful is
the integral lamp which can
be lit by pressing the button
- handy for finding keyholes
in the dark. The unit is completely sealed so we have no way of knowing whether it
has an internal cell or not._At the price of only $4. 95 it is
quite a useful device. But try to keep it out of sunlight if
you don't want to hear that tune again.
The solar keychain (Cat. Z19060) is available from all
Rod Irving Electronics stores.
Philips 21-inch high-resolution
computer monitor
ANTRIM
'TOROIDAL TRANSFORMERS
• Now made in Australia.
• Standard range 15VA co 2kVA.
• Large ex-stock quantities available.
• Competitive pricing available for OEMs & resellers.
• Simply the best transformers all round.
HARBUCH ELECTRONICS PTY Lm
90 George Street, Hornsby NSW 2077.
Telephone (02) 476 5854. Fax (02) 476 3231.
76
S ILICON CHIP
Philips has introduced a 21-inch model in its highperformance Brilliance monitor range. The Brilliance
2110 is an autoscan colour monitor that supports resolutions of up to 1600 x 1280 and an extended horizontal
scanning frequency range of up to 82kHz. T,rnse high
refresh rates are essential to obtain a stable, flicker-free
display with such large screen sizes.
.
The high resolution and display quality of the Brilliance 2110, together with its extensive digital adjustment facilities, make this monitor an outstanding choice
for the mos,t demanding applications in areas like CAD,
graphic design, DTP and professional pre-press work.
Microprocessor-based digital control of all display
parameters ensures secure and reliable setting-up. Handling a wide range of display modes is made easy by a
IAN J. TRUSCOTT'S ELECTRONIC WORLD
30 Lacey Street, Croydon, 3136. Phone (03) 723 3344; Fax: (03) 725 9443.
Now also at: 200 Smith Street, Collingwood. Phone (03) 419 8208
Mail & Credit Card Orders Welcome
We now have a range of 5,6,8,9 & 10 pin
Ask about our range of E.A.O. precision
resistor networks and a comprehensive
push button switches, motor start
range of micro's and eproms at ridiculous capacitors and Beckman Industrial
prices. Quote this ad and receive another multimeters.
5% discount.
$l6.80ea.
27C010-15 1 meg eprom 150ns..... $8.IOea.
SAB8031 P Romless Micro ........ 2.50ea.
MAB8049H Romless Micro ....... $2.50ea.
62256-LP S-Ram ..................... $9.75ea.
41256 D-Ram ................................. $2.60ea.
27C020-15 2 meg eprom 150ns....
FEBRUARY SPECIAL:
BECKMAN DM 15XL Multimeter
$119
$10.00 ea.
3mw Laser Tube & inverter $99.00 ea.
6 volt 1 watt Solar Panels
Infra Red Night Viewing Monocular (kit)
$269.00.
COMPONENT PHONE ORDER HOTLINE (03) 723 3344
ON SALE NOW
First edition Vintage Radio
Calendar, in full colour.
Featuring a selection of
Australia's most
photogenic radios.
Ideal Christmas gift for
friends and .collectors
overseas. Available from
Resurrection Radi
CREDIT CARDS ACCEPTED
51 CHAPEL STREET,
WINDSOR, VIC. 3181.
PHONE (03) 529 5639.
FEBRUARY
1993
77
choice of 22 preset modes; 14 factory
preset and the other 8 user-definable.
The Brilliance 2110 automatically
recognises the horizontal and vertical
scanning frequencies of the graphic
card to which it is connected, and
selects the corresponding display
mode. Different modes can be manually selected if desired.
Precision colour-matching provides
a choice of three colour temperature
modes: standard 6500K or 9300K settings, or a user-definable mode with
.individual RGB adjustment. This
function allows a desired colour balance to be achieved with digital precision; an important benefit in applications where critical matching of external colour references is needed.
Also newly introduced is a 20-inch
monitor (type number C2082-DAS) fitted with a Trinitron slotted shadowmask tube. This model meets the preference of some users who prefer the
Trinitron tube. Other facilities and
performance aspects of the C2082DAS are virtually identical to those of
the Brilliance 2110, except for the
maximum resolution of 1280 x 1024.
Distributed in Australia by Clear
Technology, the Philips Brilliance
2110 retails for around $5,999 including tax and the C2082-DAS for $5,160
including tax. For further information, contact Philips Components, 34
Waterloo Rd, North Ryde, 2113. Phone
(02) 805 4455.
20V/20A power supply
with variable output
If you want lots of current at up to
20V DC this power supply module is
an easy way to get it. The module is
completely built and tested; all you
LD9000 LP
gas leak detector
The LD9000 LP gas leak detector is manufactured in Brisbane
and uses a "Figaro" sensor.
Gas presence is indicated both
by an audible alarm and by flashing red lights in the display panel.
Red lights also indicate "ON" and
"charge".
have to do is mount it in a suitable
chassis with fan cooling and connect
a suitable large power transformer.
Essentially, the circuit is a simple
series regulator with five TO-3 power
transistors connected in parallel to
share the output current. At first sight,
there appear to be eight power transistors on the large heatsink but two of
these comprise the full wave rectifier
diodes while the other transistor is
Sony's CCD-TR805E camcorder - ctd from page 15
is in telephoto mode. However, such
a demonstration really does not show
how effective the system is. When
Sony released the TR-805E onto the
Australian market, they demonstrated
the effectiveness of the "steady shot"
system by mounting the unit on a
motor driven vibrator. With the
"steady shot" system switched off,
the picture was completely obliterated by the image blurring; with
"steady shot" switched on, the picture was normal - a dramatic demonstration.
78
SILICON CHIP
With such a plethora of features on
a small camcorder, you might wonder
whether it is too much for the average
user to comprehend. No doubt it is
but the beauty of the TR-805E is that
you can use as many or as few of the
features as you want and just ignore
the others. It can be used very simply
just by letting the machine do everything automatically or you can intervene as much as you like to get the
precise recordings you want.
Either way, the results are very good
and potentially better than can be
The unit is supplied with two
battery chargers, one for 240VAC
operation, the other for 12VDC
from a cigarette lighter outlet. Four
rechargeable batteries are fitted
inside the unit and these provide
up to six hours operation.
For further information contact
David Hall Electronics, 3/376 Kingston Road, Slacks Creek, Qld 412 7.
Phone (07) 808 2777.
the driver for the five output devices.
The circuit has selectable current limiting as well as short circuit protection.
The module appears to be well
made and the components are certainly rated for the high current output. It is available at $134 (Cat. SO
005) from A-One Electronics Pty Ltd,
432-434 Kent St, Sydney 2000 Phone
(02) 267 4819.
SC
achieved via any ordinary PAL monitor - you need an S-video monitor to
get the best results.
In summary then, the Sony CCDTR805E camcorder is a most impressive unit incorporating a host of features, some of which weren't even
thought of a few years ago or were
only previously available on top of
the range units.
Recommended retail price of the
CCD-TR805E is $2999. For further information, contact your local Sony
retailer or Sony Australia Pty Ltd, 3339 Talavera Rd, North Ryde, 2113.
Phone (02) 878 9712.
SC
Introducing the Tektronix 2212
Value Priced at $345 0 *
Real Analog - Real Digital Storage
No Compromise
■
60 MHz Bandwidth
■
20MS/sec Maximum Digitizing Speed
■
Analog and Digital Storage Operation
■
On - Screen Parameter Readout
■
Auto setup
■
4K Record Length
■
Parallel Printer Interface (STD)
■
2 1Ox Probes Included
■
Fully Programmable via RS-232/GPIB (Opt)
■
3 Year Warranty
For further information on Tektronix 2212 Portable Oscilloscope
Call Toll Free (008) 023342 or contact your local Tektronix office.
Tektronix
/rest and Measurement
Sydney (02) 888 7066 Melbourne (03) 836 3355 Brisbane (07) 394 1155
Adelaide (08) 223 2811 Perth (09) 242 4688 Canberra (06) 251 6111
*Price does not include sales tax.
A 2kW 24V/240VAC
sinewave inverter; Pt.5
In this fifth & final instalment on the sinewave
inverter, we present the assembly details of the
chassis and the setting up procedure. Quite a lot
of wiring is involved, especially that associated
with the DC-DC inverter & H-pack boards.
By JOHN CLARKE
· The complete kit for the ZkW Sinewave Inverter (from Rod Irving Electronics) will include the assembled
DC-DC inverter transformer, Tl. This
transformer requires careful construction techniques. The 1-turn copper
sheet primary windings must be carefully terminated in order to obtain an
80
SILICON CHIP
exact balance between them, while
the secondary is quadrifilar wound
with 2mm enamelled copper wire.
The chassis for the inverter has removable side panels and lid. The DCDC inverter and H-pack PC boards,
together with the associated Mosfets,
IGBTs and diodes, mount onto the
side panels which each have two vertical heatsinks. Rectifier diodes D3D6 are mounted on the rear panel.
The assembly procedure given in this
article assumes that all metalwork has
been drilled. Ifnot, you will naturally
have to drill all holes before assembly
begins.
The wiring involves heavy duty cables capable of carrying 130 amps,
plus mains-rated cable and light duty
wiring between the PC boards. Because there is such a large variation in
the wiring, we recommend that you
follow this article and the wiring diagram very carefully.
Transformer board
We will begin with the transformer
board, since this requires a considerable amount of mechanical assembly
and wiring. This is a bare fibreglass
board measuring 175 x 370mII_l and it
accommodates the DC-DC inverter
transformer (Tl) and associated components.
As supplied, the two Clipsal BP165C12 brass link bars have 12 pairs
of screw terminals plus a 5/16-inch
bolt at one end. Both these bars are
cut to give one block with a bolt and
two pairs of terminals and one block
with nine pairs of terminals. To do
this, remove the two screws at the
third pair of terminals (near the bolt)
and cut the bar across the centre of
these screw holes. Clean up each end
with a file.
One of the short ends with the bolt,
designated LB3, is used to mount fuse
Fl. The two 9-pair terminal blocks
are designated LB4 and LB5. You will
need to drill a mounting hole at the
cut end for each of the LB3, LB4 and
LB5 terminal blocks.
Termina~ strips
Three 4-way 30A insulating terminal strips are required for the inverter
and these are cut from the 12-way
30A terminal strip (Clipsal BP535 or
593/30) using a sharp knife.
If the transformer board has been
supplied undrilled, you will need to
mark it out and drill it before assembly can begin. To do this, arrange the
components as shown on the wiring
diagram. The LB1, LB4, LB5 and LB6
terminal blocks are placed with their
outside edges about 5mm away from
the edge of the board.
Note that the LB1 block bar must
have its top edge about 40mm from
the top edge of the board to allow
space for the bank of five l0µF capacitors. LB2 is located 28mm away
from LB1.
Similarly, the bottom edge of LB6
should be spaced 30mm back from
the adjacent edge of the board to provide room for the three lOµF capacitors. A gap of 10mm separates LB7
from LB6. LB2 and LB3 must be correctly spaced to allow fuse Fl to be
bolted between them.
Transformer Tl is mounted with its
righthand bobbin in line with the
righthand edge of the board and is
secured with two bolts. These bolts
pass through a sheet metal retaining
clamp which sits on top of the transformer. This retaining clamp also sup-
This close-up view shows how inductors L3 & L4 are secured to a fibreglass
board using an 8 x 80mm bolt & nut. This board is then mounted vertically on
the rectifier board using two right-angle brackets.
ports a 4-way 30A insulating connector strip.
When you have positioned all the
hardware on the board, mark out all
the holes and drill them. That done,
you can mount the transformer and
the associated hardware. The transformer should be mounted with the
primary wires close to the board and
the red secondary wires directed towards fuse Fl.
Four pieces of copper sheet measuring 28 x 60 x 0.6mm will be needed
for mounting the 10µF supply bypass
capacitors - see Fig.20. These will
have to be drilled or punched so that
they can be retained by the 5/16-inch
bolts on blocks LB1, LB2, LB6 and
LB7. They will also need to be drilled
to accept the leads of the lOµF capacitors.
Five lOµF capacitors mount be-
tween LB1 and LB2, while three lOµF
capacitors mount between LB6 and
LB7. The capacitors are soldered to
the copper plates before they are
mounted onto the brass terminal
blocks. Note that the copper sheet
mounted on LB2 is located beneath
the lug of fuse Fl.
The two copper sheets which mount
onto blocks LB6 and LB 7 are each
secured with a 5/16-inch bolt and two
screws, as shown on the diagram of
Fig.20.
130-amp cables
Short black and red 130A cables
are used to connect LB1 to LB6 and
LB2 to LB7. These should be kept as
short as possible to minimise any internal voltage drop due to resistance
and inductance. If necessary, you will
need to strip each end and fit suitable
FEBRUARY
1993
81
130A
CABLE
(BLACK)
-
X'
THERIIAL
CUTOUT
TH1
TO THERIIAL
CUTOUT TH2
y•
J
SOLDER LUG
BOLT TO
REAR f'ANEL
........- - - . . - 10uF
,--
COPPER
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PCB
130A
CABLE
(RED)
I
1
Q' FUSE2
FRONT
PANEL
LB1
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terminal lugs to them using an p.ydraulic crimping press or by soldering them with a blowtorch.
If you don't have these facilities, an
82
SILICON CHIP
auto electrician will be able to do the
job. The main 130A supply leads will
also need to be fitted with suitable
lugs and battery terminals. These are
terminated in a similar manner to the
cables described above.
Do not connect the battery leads at
this stage, since the transformer board
MOUNTED ON BACK PANEL
- - .......
,
05
06
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04
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RECTIFIER PCB
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SINEWAVE PCB
SC11309923
TO
FUSE 5
t15A INSULATED MAINS WIRE
has yet to be mounted inside the case.
However, you can secure the cables in
position between LB1 and LB6 and
between LB2 and LB7. Note that the
TO
EARTH
OF GPO
TO N OF
GPO
Fig.20: follow this chassis wiring diagram carefully when wiring up the inverter
be sure to use the specified grade of wire for each connection. In particular,
note the two 130A cables linking LB1 to LB6 & LB2 to LB7. The two thermal
cutouts (TH1 & TH2) are mounted on the side panels immediately adjacent to
the heatsinks at the back of the chassis.
&
FEBRUARY
1993
83
using three short lengths of 15A mains
cable.
When wiring the CS1 terminal strip,
make sure that the secondary wires
from bobbin 1 connect to the two
lefthand terminals and that the secondary wires from bobbin 2 connect
to the two righthand terminals. The
blue and brown output wires which
connect to the opposite side of CS1
should not be connected until the
transformer and rectifier boards have
been installed in the case.
Chassis side panels
The two thermal cutouts are secured to the side panels using machine screws &
nuts. If the heatsink temperature rises above 80°C, these cutouts open & switch
off the power to the DC-DC inverter circuitry.
As mentioned previously, the two
side panels of the chassis are used to
support the DC-DC inverter PC board
and the H-pack PC board. Each board
is mounted centrally on its respective
side panel on four 6mm metal standoffs. Before going further though, it's
a good idea to check that all the mounting holes have been deburred. This
will prevent damage to the mica insulating washers that are used to isolate
the power semiconductor devices
from the chassis.
The first step in assembling the side
panels is to fit the four heatsinks. To
ensure good thermal transfer, apply
heatsink compound to the back of
each heatsink before attaching it to its
respective panel using two screws (one
at the top and one at the bottom).
The PC boards can now be mounted
on the 6mm standoffs. The power
semiconductors for the H-pack PC
board - IGBTs Q17-QZ0 and diodes
D10-D13 - are mounted as shown in
Fig.23. Note that two mica washers
are used between the tab of each of
these devices (Q17-Q20 & D10-D13)
and the side panel. This is to prevent
Diodes D3-D6 are bolted to the rear panel for heatsinking. Note that they must
be insulated from the panel using mica washers & mounting bushes.
copper sheets that carry the 10µF capacitors go underneath the cable lugs.
Wiring the transformer board
The primary wires from the transformer are connected to brass link
bars 1B2, 1B4, 1B5 and 1B7 as shown
in Fig.20. The four blue primaries connect to 1B4, the four black primaries
to 1B5, the four yellow primaries to
1B2 and the four red primaries to
1B7. Cut these leads as short as possible while still allowing a small amount
84
SILICON CHIP
of slack when they are connected.
They can then be laced together neatly
with cable ties.
The secondary leads terminate at
insulated connector strips CS1 and
CS2 (two leads in each terminal). Cut
the leads so that a small loop is formed
between the transformer and terminal
and strip back the plastic sleeving
and enamel coating before securing
the wires into the terminals. The terminals on the opposite side of connector strip CS2 are interconnected
high voltage punch-through of the
mica washers.
Apply a smear of heatsink compound to all mating surfaces before
securing each device with a screw
and nut. This done, use your multimeter to check that the metal tab of
each device has been correctly isolated from the chassis.
The power MOSFETs on the DC-DC
inverter board should not be secured
to the side panels at this stage. This is
because the tabs of these devices are
wired to the link bars on the transformer PC board and we're not up to
that stage yet.
Rectifier board assembly
This partly assembled board can
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Fig.21: this diagram shows how the parts are arranged on
the rear panel, as viewed from inside the chassis.
now be completed. The 4-way 30A
terminal strip is mounted on the board
with screws and nuts, while the 680µF
400VW filter capacitor is mounted
using its integral stud, star washer
and nut. The 25µF 370VAC capacitor
is mounted with a 45mm-dia. collar
bracket.
Fig.22: the inside front panel layout. Sleeve the fuse
terminals with heatshrink tubing to prevent shock.
The toroidal sinewave filter inductors, L3 and L4, mount side-by-side
on a vertical piece of bare fibreglass
board (100 x 55mm). This board is
secured to the rectifier board using
two L-shaped brackets. Note that the
vertical board has a rubber grommet
to allow the wires from L4 to pass
through it and thence to the 30A terminal strip. •
L3 and L4 are secured to the vertical board with a bolt which passes
through their centres. This is fitted
with a nut and 45mm washers at each
end. The L-shaped brackets are secured to the rectifier board using two
FEBRUARY
1993
85
NUT
CI:J:l
WASHER=
- -- - - INSULATING WASHER
c:::=========::l
CHASSIS
HEA TSINK FOR
...__ _ _ _ _ _ __. Q5-Q20, D10-D13
screws which do double duty in retaining two board standoffs).
Chassis work
Now is the time to assemble the
components inside the chassis. As
shown in Fig.21 (back panel), the two
cable glands are each mounted with
the securing nut inside the case. With
those fitted, the transformer board,
sinewave board and rectifier PC board
can all be mounted on standoffs inside the case. The 15A EMI filter can
also be mounted at this stage.
The front panel hardware can be
mounted next. This hardware comprises the front panel label, the two
fuseholders, power switch S1, LED1
Fig.23: this diagram
shows the general
mounting details
for the TO-220
devices. Smear all
mating surfaces
with heatsink
compound before
bolting the various
assemblies together
& note that two
insulating washers
must be used with
Q17-Q20 & D10D13 to prevent
voltage punchthrough to chassis.
and the mains GPO (double power
point) - see Fig.22.
The positive and negative battery
leads are passed through the glands
and bolted to the LB3 and LBl terminals on the transformer board. This
done, tighten the gland nuts (from
outside the chassis) to anchor the leads
and prevent any stressing of the transformer board.
The O. lµF capacitor associated with
LB 1 can now be mounted. One lead is
soldered to the copper sheet while
the other lead is connected to a solder
lug which is fixed to the rear panel of
the chassis.
Diodes D3-D6 are mounted on the
rear panel using insulating bushes and
WARNING!
The internal wiring of the 2kW inverter is highly dangerous. There are lethal
voltages present while the inverter is running and these can remain even after
the inverter has been switched off.
Before touching any part of the inverter circuitry, always check the DC voltage
across the 680µF 400VW capacitor terminals. This capacitor is extremely
dangerous when fully charged and can only be regarded as "safe" when the
voltage across it is below 20V. This voltage is reached a couple of minutes after
the inverter is switched off.
As an extra safety precaution, always place the lid on the inverter before
powering up. The lid will protect you from flying debris if there are any catastrophic component failures. Don't be rash-this can happen. At the very least,
wear eye protection.
You should also take considerable care with the battery bank. Ideally,
batteries used indoors with inverters or uninterruptible power supplies should
have explosion proof vents and should be housed in a separate cabinet.
Even so, there is still a risk of explosion since there is a risk of hydrogen being
present after charging. Always switch the inverter off before connecting or
disconnecting the battery leads to avoid sparks occurring at the battery terminals.
Note that a small spark may occur when first connecting the battery leads,
even with the inverter switched off. This is due to the charging current into the
eight 10µF capacitors connected across the supply leads.
86
SILICON CHIP
mica washers. Use heatsink compound on the metal tabs and the mating surface of the rear panel to ensure
good heat transfer.
Check that the metal tab of each
device is isolated from the rear panel
by measuring the resistance with a
multimeter.
Chassis wiring
Start by wiring between the DC-DC
inverter board and the transformer
board. The blue and brown output
wires (15A cable) from the DC-DC inverter board to the rectifier PC board
are connected using 6mm crimp eyelet lugs. These lugs are secured using
screws which thread into nuts that
were previously soldered underneath
the board.
The sources of MOSFETs Q5-Q10
are connected to LB6 on the transformer board, while the source wires
from Q11-Q16 are connected to LB1.
The source wire connections are made
via crimped eyelet lugs which are retained by 4mm screws to the PC board.
The connections to the drains of
Q5-Q16 are made (using 15A cable) in
a similar manner, with the eyelet lugs
being placed directly against the metal
tab and under the insulating bush of
each MOSFET (see Fig.23) . The drain
leads from Q5-Q10 go to LBS, while
the drain leads from Q11-Q16 go to
LB4.
Tie the wires into neat bundles with
cable ties and then secure the side
panel to the chassis.
The low current wiring is run mainly using heavy duty (10A) hook-up
wire. The exception is the shielded
cable that's run between the rectifier
PC board and the DC-DC inverter
board.
Three supply leads run from the
DC-DC inverter board to the sinewave
generator board, while 14 leads run
from the sinewave board to the Hpack drive PC board (refer to the board
testing procedure described last
month).
Finally, there are the leads from
LB1 (positive side of fuse Fl) to the
front panel switch S1, from LB6 to the
DC-DC inverter board, and from the
DC-DC inverter board to the thermal
cutouts. The thermal cutouts (TH1
and THZ) should be wired before they
are secured to the chassis.
When running the shielded cable
from the DC-DC inverter board to the
rectifier board, use heatshrink sleeving
•
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•
This is the view inside the fully completed prototype. Check all wiring carefully
when it is completed & be sure to follow the low-voltage test procedure outlined
in the text before applying full power to the inverter.
over the cable ends to provide stress
relief.
High voltage wiring
The high voltage wiring involves
the rectifier and H-pack drive boards,
phis the output to the mains filter,
GPO and associated fuse. This wiring
must be run using 15A mains-rated
cable, much of which is terminated
88
SILICON CHIP
using crimped lugs. Use star washers
under all the screws to ensure good
connections to the wiring lugs.
The connections to the 25µF
370VAC capacitor and to the mains
filter are made using female quickconnect crimp lugs. Make sure that
the earth connections from the mains
filter to the chassis and from chassis
to the earth terminal of the GPO are
made with the correct green/yellow
striped mains wire . .
The high voltage wires to the Hpack drive board are fitted with eyelet
crimp lugs secured with a star washer
and screw. Don't forget to install the
1µF 500VAC capacitor between the
+365VDC terminal and the 0V terminal.
Testing
The 2kW Sinewave Inverter comprises a large number of expensive
The mains filter at the front of the chassis is necessary to reduce high frequency
interference to television & radio reception.
components which can be damaged
with catastrophic results if there is an
error in' the construction or wiring.
After you have finished your wiring,
we recommend that you check each
lead against the wiring diagram and
then against the relevant circuit diagram just to make sure that all is correct. If you don't, the bill for blown
components can be quite high.
We recommend that you follow the
testing procedure to the letter.
Low voltage test
Before testing the inverter fully, it
is wise to check that the high voltage
circuitry will operate at low voltage.
To do this, disconnect the low current
+24V lead from 1B3 and connect a
clip lead between this lead and the
+365V terminal on the H-drive PC
board. This done, connect a clip lead
between the negative terminal of the
680µF capacitor on the rectifier PC
board and the negative battery lead.
Finally, remove fuse F4 from the rectifier PC board. This allows the entire
circuit to operate at 24V, including all
the high voltage circuitry.
Now connect a 24V power supply
between the negative battery lead and
the low current +24V lead (do not
connect power to the positive battery
lead). This will power the inverter
drive circuitry but not the MOSFETs
(Q5-Q16). Consequently, the DC-toDC inverter section of the circuit will
not be running but the 24V applied to
the H-drive circuitry will produce a
low voltage sinewave at the mains
GPO.
An oscilloscope can be used to
monitor this sinewave at the GPO. If
the power supply you are using is
fully floating (ie, neither of its outputs is grounded), you can use one
probe to earth one of the GPO terminals. If the power supply is grounded,
then the oscilloscope must be used in
its differential mode to avoid shorting
the supply output.
Note that there will some distortion in the output sinewave due to the
voltage drop across the IGBTs in the
H-drive circuitry. In normal operation, this distortion will not be present
since the voltage drop across the IGBTs
will be negligible in comparison to
the 365V supply.
When operation at 24V has been
confirmed, a full voltage test can be
run. You will require a 24 V battery (or
two 12V batteries.in series) which is
capable of supplying 120A for at least
15 minutes.
Restore the wiring inside the ZkW
Sinewave Inverter to its normal condition and re-install fuse F4. Rotate
trimpot VRl on the DC-DC inverter
PC board so that its wiper is pointing
directly upwards. This should set the
output voltage at just below 240VAC.
Before connecting the inverter to
the batteries, it is advisable to install
a 15A automotive fuse in the positive
battery lead in place of fuse Fl. This
will blow well before any damage can
occur if a fault is present. This fuse
can be supported by two stout lengths
of tinned copper wire attached to 1B2
and 1B3.
Now replace the lid on the inverter.
Make sure that the inverter is switched
off, then connect the battery leads
(with the 15A fuse in circuit). Connect a digital multimeter set to read
240VAC to the GPO socket and switch
on the inverter. The AC voltage should
quickly rise to over 200VAC (this can
be adjusted later with VRl) and the
15A fuse should remain intact.
If a DC clamp meter is available,
measure the DC current supplied to
the inverter. It should be about 3A for
no output load.
Switch off the inverter immediately
if you smell anything burning and
correct the problem before switching
on again. Be sure to follow the safety
precautions outlined in the warning
panel when working on the inverter.
For further testing, you will need
some loads. Several 100W light bulbs
connected in parallel using bayonet
holders are useful, while a bar radiator can provide a 2kW load.
The inverter will drive a 300W load
using a 15A fuse in place of Fl. Measure the AC voltage across this 300W
load and note the reading. This done,
switch off the inverter, disconnect the
battery and remove the lid.
Now measure the DC voltage across
the 680µF capacitor and wait until it
drops to less than 20V. When it does,
rotate VRl slightly clockwise if the
output voltage was less than 245VAC
for a 300W load and slightly anticlockwise if the voltage was greater
than 245VAC. This done, check the
output voltage across a 300W load
again and readjust VRl as necessary.
Once the inverter is operating correctly at 300W, disconnect the 15A
fuse and re-install fuse Fl. The inverter is now ready for testing at loads
up to 2kW.
To do this , run the inverter at 2kW
and check for excessive l;ieat from the
heatsinks at the side of the case. The
MOSFETs will normally run quite a
lot warmer than the IGBTs. The DC
current drawn from the inverter will
be about 110A.
After operating the unit for a few
minutes, switch it off and check the
internal components for overheating
(be sure to observe the safety precautions). Note that 13 and 14 will normally run quite hot at full load.
Finally the sine waveform can be
checked using an oscilloscope. The
waveforms should be similar to those
published on page 30 of the November 1992 issue of SILICON CHIP.
SC
FEBRUARY
1993
89
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TRANSISTOR TESTER
ROD IRVIN Have you ever deaoldered • auapect
ROD IRVIN trsnsistor only to find that it checks OK?
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trouble shooting exerci- are often
IRVIN hindered by Ihle type of false alarm, but
IRVIN many of them could beovoided with an
IRVIN " in•clrcuit'.' component tester, such ■a the
IRVIN EA Handy Teater. (EA Sept. •a3) 83TTII
IRVIN K10080............................. $22 .95
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GENERAL PURPOSE
PREAMPLIFIER
~
A general purpose atereo preamplifler
uaing a single Lt.1382 IC which can be
tailored lor use with magnetic plckupa,
tape recorders, and microphones by
changing• few components
(ETI445) (ETI July •1&)
m
The ETI·569 Solar charger ia deaigned to
charge any 111nd1rd 12 V lead acid car
~ttery in any area where maina power ia
unavailable. It la ideal for remote data
acqulaltlon atatlona. caravana and boata.
OI coar• there are 01h er soloar chargers
nd
arou ' but these are extremely
(ETI 480)
~~~~£~~~~~:~:::~:::::
~;~1
..· '.iclty
11
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1 1 1 ~ :••.$
13 95
•
everything•• on the one pcb.
.
.
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BALANCED INPUT
IRVI~
IRVI~
DIFFERENTIAL PREAMP
IRVI~ Th'
.. r
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IRVI
,a
vera1t1 1e ,11 Ie pream11 naa • oat o
1pplicatlon1 In the audlo-and•beyond
ROD IRVI range, not the leaat of which would be 18
ROD IRVI I balanced mic preamp.
ROD IRVI
•
ROD IRVI (Ell 461 Dec 82 ETI)
ROD IRVI K10070 .............................$19.95
ROD IRVI
.
. .
ROD IRVI DISCOUTE
,
ROD IRVI
··
ROD
IRVI Thla kit makes your
~
I
AMPLIFIER CLASS B.
One of the handiest "tools" for the
electronics experimenter ia a genuine
purpose audio amp. Thie module will
work from a wide rsnge of aupply
voltages, haa very good senaitivity, ia
robuat, reliable and easy to build tool
(ETI 453) ETI April •so)
K10065
$14 95
··············...............
•
PLAvMASTER 300W
r
100 W AMPUFER MODULE
(ETI 480)
Similar to the above module but thia one
ia 1oow1tta of power.
Heataink optional extra
K10045............................$32 .95
AMPLIFIER
ohm■
tig~~g~:gi
LECTRONICS
LECTRONIC~
Heatslnk optional extra
K10040 .... ........................$27.95
• ···· .. '
ELECTRIC FENCE KIT
Main to battery powered, thia electric
fence controller ia both inexpensive and
·n B aed on •n auI omoII ve .ign,·1·ion
vera, 1e. •
coil, it aould prove an adequate deterrent
to all manner ol livestock. Additionally it's
operation conforms to the relevant
clausea ol Auatrslian Standald 3129. (EA
Sept..82)82el9
K10110 .............................$23.95
MIKE PRE AMP
300WATTSINT04
LECTRONICS
LECTRONICS
LECTRONICS
LECTRONICS
LECTRONICS
expenaive. With the ETI-569 the emphaaia LECTRONICS
SOW AMPLIFIER MODULE
·
GENERAL PURPOSE
!:::'
l
K 10055..•.•.•.....................$14.95
SOLAR GENERATOR
LECTRONICS
LECTRONICS
ILECTRONICS
ILECTRONICS
LECTRON ICS
LECTRONICS
i' LECTRONICS 1
LECTRONICS
LECTRONICS
LECTRONICS
LECTRONICS
•
lECTRONICS
.LECTRONICS
tECTRONICS
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lECTRONICS
lECTRONICS
J.ECTRONICS
lECTRONICS
:LECTRONICS
:LECTRONICS
1LECTRONICS
1LECTRONICS
1LECTR0N1cs
ILEC TRONICS
This module will deliver up to 200 watta
High quaility tranaformera for matching
;s ROD IRVI lights do amazing
into an Bohm load. Comprehensive
balanced microphones into unbalanced
ILEC TRONICS
;s ROD IRVI things. With 4 llght channels controlled
protection ia included and a printed
inputs are quite expensive. This simple
ELECTRIC FENCE
ILECTRONICS
'S ROD IRVI by 4 separate audio channels. Eg.
circuit board bringa it all together In•
presmplifier will accept balance inputs
ILECTRONICS
ROD IRVI Forward, reverse, auto reversing chaser
rugged 818Y·l 0•build module. It can be
directly.
CONTROLLER
ILECTRONICS
;s ROD IRVI patterns, alternating light pattern■,
built in either lully• complementary or
(ETI May ·n, ETI 449)
Reatore the discipline to the farm or
ILECTRONICS
0
19
;s ROD IRVI adju111ble rate lor light patterns,
quaai-complementary ve lona, • output
K10060 ............................$11.95
allotment with this new electric fence
ILECTRONICS
:s ROD IRVI aimultaneoua strobe on all four channels.
tranaialor ahortagea should be no
controller. It features higher output power ILECTRONICS
:s ROD IRVI Plus many more features! (Sil Chip July
problem at 111·
1
MORE KITS
f
and lower current drain than the previoua ILECTRONICS
1
1
:s ROD IRVI 1988)
(80pa6) (EA July ·ao)
design.
ILECTRONICS
;s ROD IRVI K10130............................$155.00
K10085 ...........................$109.00
COMMING SOON!
(EA Dec. ·as,a5ef11)
1LECTRONICS
1
;s ROD IRVI
L--- - --------------.J
K10115 .............................. $61.95 LECTRONICS
;s ROD IRV1~l - - - - - - - - - - - - - . . . . ; ._ _ _ _ _ _ _ _ _ _ _ _ _....;.- = = = = = = = = = = = = =.....= = = = = = = =- - - - - - - f:LECTRONICS
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Every service man should have
I
II f th.
1·
at eastonero O
1squa1ty
"Bene lec" speaker cable in their
box.
Flat tw·1n f·1gure 8
·
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1410.14mm
;s RODIRVI
ROD IRVI 2C
BC xPVC
lnsul 50V
Go-Go
LAMIN ATOR
,-. ,
la that precious photo of your
loved ones in your wallet
getting a bit tattery? Don·t
lose those precioua memories
protect them by laminating them
with your own l1mln1tlng machine
Important Bualneaa cords, membership
cards,
recipeaetc.laatallfetimelongerwhen
laminated.
Now ROD IRVING ELECTRONICS have
Imported
this laminator that your budget can
allord.
Don•t pay hundreds of dollar• for some
big machine
l'aya 1,40 f the price for an attractive
compact laminator that ia ao simple to
use.
up in only 2 to 3 minutes.
A911 00 .............................$95 .00
.--7,=::==T71.
1t•s Iha cheapest it has aver bean! Tha
famous OKILASER 400 Laser printer at
- ~·
if==ti1b.. ·:--;:
.
~- - · ...
!-!~""""~~:~;~J l t~g;~g~:g;
only $1299! Reliable and compact, it
fits neatly into Iha smallest of offices.
Highly reliable dua to its latest LED
imaging technology. Tha OL400 offers
axcallant print quality, superior paper
handling, and a variety of fonts which
rivals soma of Iha more expansive
laser printers on Iha market
5 year Warranty On
LED system head.
No moving parts (LED SYSTEM
HEAD)
recycles its own toner! Approx.
1.Bipercopy.
Just $1199 00
WELLER
•
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SOLDERING -~
ST'A'
JION
,.._-#'¥"
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:s ROD IRVI In 100 metre rolls. Black or Grey
,LECTRONICS
:s ROD IRVI (Sorry this has no black polarity
with tempersture
.~ \
'. LECTRONICS
;SS RROODD IIRRVVII identification stripe down the side
controlled aoldering iron.
.
A tramaformer powered soldering station, complete with a low voltage, temperature
:S ROD IRVI of the Wire.)
cqntrolled aoldering pencil. The special Wellar "closed loop" method of controlling
:LECTRONICS
:s ROD IRVI UsuallY, S2a,ee- 1·9
10+
Laminate Shaats.... 95mm x 57mm
maximum tip temperature iaemployed, thereby protecting temperature aenlltive
:LECTRONICS
:s ROD IRVI
$
$9
(2.25" x 3.25")
component• while the grounded tip protects voltage and current aenaitive components. :LECTRONICS
:s ROD IRVI W 11200 .... .. ..... 1O.OO
.00
for business cards A91110 .. $18.95
The aolderlng pencil features• atalnleaa ateel heater construction,• non.burning
LECTRONICS
;s ROD IRVI
silicon rubber cord and a large selection of iron plated tip■ in sizes from 0.8mm
LECTRONICS
100
;s ROD IRVI
.pack of
diameter to 6.0mm diameter with• choice of tip temperature of 315° C/600°F, 370°
LECTRONICS
;s ROD IRVI 50 ohm Ethernet cable
c11oc,o F and 430" Ct800"F.
LECTRON 1cs
;s ROD IRVI
Laminate Shaats.... 156mm x 112mm
LECTRONICS
;s ROD IRVI P39502 2 Metre................. $9.95
(4.25" X 6.75") for photos with
T12500
LECTRONICS
;s ROD IRVI P39503 3 Metre.................$11.95
punch holes for photo album
LECTRONICS
;s ROD IRVI P39505 5 M t
$14 95
A91111.. ......... $11,95 pack of 24
,______
LECTRONICS
;s ROD IRVI
e re.................
.
...
LECTRONICS
;s ROD IRVI P39510 10 Metre...............$24.95
LECTRONICS
;s ROD IRVI P39520 20 Metre...............$34.95
Laminate Shaats ....135mm X 95mm
LECTRONICS
nd
4
5116
3
;s ROD IRVI Theae are relldymade cablea to aave you
( 3/ " X S
") for photos a
Thie la not your aversge EPROM Ersaerl
LECTRONICS
rd
;s ROD IRVI time & effort of lnatalling your Networks at
ca •
Sure tt erssea your El'ROM'• quickly and safely and will erase up to
LECTRONICS
;s ROD IRVI school In bualneaa or at home.)NICS RO
A91113 ........... ......... .$8.95 pack of 24
9 x 24 pin devicea In about 40 minutea.(leaa for leaa chips). But with thia one you don·t
;s ROD IRVI
have to waate your time atanding around -iting lor them.
;s ROD IRVI
Laminate shaats .... 110mm x 170mm
Thie EPROMe,_, haatlmer to allow you to "set and lorget". By uaingthetimer
LECTRONICS
;s ROD IRVI
(4.25" x 6.25")
A91.112 ....... $10.95
!unction you not only aave money by r11uaing your EPROM's but you alao aave precioua LECTRONICS
;s ROD IRVI
time by doing other jobe while the er••• ia working. And you•n never have to worry
LECTRONICS
;s ROD IRVI
about lorgettlng to tum it off and "cooking" your EPROM'a.
LECTRONICS
;s ROD IRVI
EPROM SPECIALS
Chooaefrom a range of different sett Inga from 15 minutea to 40 minutes depending on .LECTRONICS
;s ROD IRVI
1·9
10+ 100+
the lntenalty of the UV aource.
LECTRONICS
1
;s ROD IRVI
27C64-20 $4.50 $3.90 $3.50
• The chip door haa a conductive foam pad.
1LECTRON ICS
;s ROD IRVI
27C512-15 $8.00 $5.50 $5.00
• High lntenalty at the chip aurlace enaurea EPROM'a are thoroughly erased.
LECTRONICS
:s ROD IRVI
$9.95 2 7e256 •20 $5 •00 $4 50 $ 4 OO
• Engineered to prevent UV exposure Save $20 $149.00
LECTRONICS
:s ROD IRVI
•
.
:LECTRONICS
:S ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS HOD IRVING E:LEC l HONICS HOD IRVING E:Ll::C I HONICS HUU IHVINu t:LECTRONICS
; s ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS
'S BOO IBVING ELECIBONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS ROD IRVING ELECTRONICS
"'"c c, CCTDO!IIICC' coo ID\/11,lQ. Cl CCT RONICS COO IRVING ~LECI~
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Heat■
Usually $179.00 This month only $149.00
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ELECTRONICS ROD IAVING ELECTRONICS ROD IAVING ELECTRONICS
ELECTRONICS ROD IAVING ELECTRONICS ROD IA\IIN.G ELECTRONICS
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...... · - - - -ROD IAVING ELECTRONICS ROD IAVING E' ECTRONICS ROD IAVING ELECTRONICS ROD IAVING ELE
ROD IAVIN G ELECTRON ICS ROD IAVING E ':'CTAONICS ROD IAVING ELECTRONICS ROD IAVING ELE
ROD IAV ING ELECTR ON ICS ROO IAVING ELECTRON ICS ROD IAVING ELECTRONICS ROD IAVING ELE
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ELG 1.2M JAP F.D.D. 512K VGA CARD
EU; 40M HARD DISK DRIVE,
.--e-.-=..,.,..,--,
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EL~ MINI CASE & 200W POWER SUPPLY
ELE
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•• 2 MEG RAM EXP TO 16 MEG
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40 MEG HARD DISK
1.2M JAPANESE BRAND F.D.D
101 EXTENDED "CLICK" KEYBOARD
~LE SERIAL PARALLEL GAMES PORTS
ELE
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WARRANTY IBM' COMPATIBLE
I.
ELE
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ELE • SHAREWARE SOFTWARE
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OD IAVING EU
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OD 1AV G ELE
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$159
IN
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OD IAVING ELE
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$
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CD ROM SOUND BLASTER PACK. ........... $949
PARRADISE WINDOW ACCELERATOR ..... $275
$1 39 9
$1099
· gg ::~:~~~t:
J .....:.:-:.:..:.-=-:a
EXTRA RAM
(
512K VGA CARD (256 COLOURS) IBM' COMPATIBLE
4 YEAR PARTS & LABOUR WARRANTY
SPEADSHEET, WORDPROCESSOR & DATABASE
SOFTWARE INCLUDED.
"SHAREWARE SOFTWARE
ASSEMBLED & TESTED
'
TAX Inc
IN AUSTRALIA
TAX EX
$1 319
.
1~io'-~DRDosa.oADD.................... $75.oo
~.oo-iEtll-'!l(.ENOif.~~CT
MSDOS5.0ADD ................... $99.00
~t-1J..i11.lS~~1.iv-g~3)543ZIG6 MS DOS 5.0 & WINDOW 3.1 .... $179.00
OIS~s -11\\01.f.~..
lM VGA CARD ... .................... $100.00
••
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WITH 2
. ..... OD IAVING ELE
OPTIONAL EXTRAS
ADD PRICE TO BASE SYSTEM COST.
Add$25;~r~~~~:~~:r1· •·
$1,165
OD IAVING EU
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MlNI TOWER.$50 FULL TOWER.$200 OD IAVING EU
RITRON · [1.111~,, · RITRON. ·· 111 Jr RITRON ill!P~;1!~1t:
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4 MEG RAM
EXP TO 16 MEG
65 Mhz LANDMARK SPEED TEST
40MEGHARDDISK12msACCESS
TIME. 1.2M JAPANESE BRAND F.D.D
101 EXTENDED"CLICK" KEYBOARD._______
MINI CASE & 200W POWER SUPPLY SERIAL, PARALLEL,
GAMES PORTS 512K VGA CARD, SUPA VGA COLOUR
MONITOR
(1024 x 768 Res) 0.28" 4 YEAR PARTS & LABOUR
WARRANTY SPEADSHEET, WORDPROCESSOR &
DATABASE SOFTWARE INCLUDED. •SHAREWARE SOFTWARE
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MEGOF
RAM!
• 80486SX-25 CPU
4 MEG RAM
EXP TO 32 MEG
75Mhz LANDMARK SPEED TEST
•• 40MEGHARDDISK
1.2M JAPANESE BRAND F.D.D
101 EXTENDED"CLICK" KEYBOARD
MINI CASE & 200W POWER SUPPLY ._______
. 4 YEAR PARTS & LABOUR WARRANTY
.
SERIAL, PARALLEL, GAMES PORTS. 512K VGA CARD
SUPA VGA COLOUR MONITOR (1024 x 768 Res) 0.28" DP
SPEADSHEET, WORDPROCESSOR & DATABASE
•
SOFTWARE INCLUDED. 'SHAREWARE SOFTWARE
WITH 4
MEG OF
RAM!
$1 449
c
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WITH 200 MEG DRIVE
.
$1 1899 TAXINC.
$1,585 TAX EX.
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••• 256K ON BOARD CACHE. 4 MEG OF RAM
:; 157Mhz LANDMARK SPEED TEST
WITH 4
••• 40MEGHARDDISK
MEGOF
••• 1.2M JAPANESE BRAND F.D.D
/ 101 EXTENDED"CUCK" KEYBOARD
RAM'
( SERIAL, PARALLEL, GAMES PORTS
"
:0 512K VGA CARD. IBM' COMPATIBLE
.. SVGA COLOUR MONITOR (1024 x 768 ReM>lutlon) 0.28.. DP
MINI CASE & 200W POWER SUPPLY
4 YEAR PARTS & LABOUR WARRANTY
SPREADSHEET, WORDPROCESSOR 6 DATABASE SOFTWARE.
$
IN AUSTRALIA.
$1 ASSEMBLED
469 & TESTED
WITH 200 MEGORIVE
TAX
·.
'
$1,919 TAXINC.
$1 1 600 TAX EX.
INC.
$ 1,225 TAX EX.
DDIIRRVVII NNGGE
ELLII
p.~l'-V'"v,::::.·:;';:::;"';:;;::;;;::::::,p D IRVING ELI
$1,870
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WITH 200 MEG DRIVE
2 ' 249
$2 ' 699
TAX INC.
TAXINC
$2,245 TAX EX
TAX EX.
RITRON .
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DI AVINGELI
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VINTAGE RADIO
By JOHN HILL
The awakening of the Dragon
From a collector's point of view, horn speakers
are valuable items & any receiver from the mid
1920s is only half complete unless it is matched
up with an old horn. While these ancient
loudspeakers all sound much the same, some
are far more desirable than others.
A large proportion of early radio
receivers used headphones as a sound
reproducer. Users of crystal sets and
1-valve and 2-valve receivers had no
other choice; these low powered sets
lacked sufficient output to drive a
loudspeaker. Radios having three or
more valves were a different matter these were capable of loudspeaker
performance.
Loudspeakers were mostly separate
items in the 1920s and the horn
speaker was by far the most common
type. Cone speakers came into vogue
during the latter part of the decade,
after which the old horns quickly fell
from favour. It was at about this stage
of home radio evolution that manufacturers started to tidy up domestic
radios by building them into complete self-contained units. Prior to this,
radio was a fairly untidy affair with
most sets consisting of several bits
and pieces.
Good points & bad points
The old horn speaker had both its
good and bad points - mostly bad!
These two derelict Amplion Dragons were combined into one unit. The water
damaged flare on the left had only two good segments & these were used to
replace two broken segments in the flare on the right.
96
SILICON CHIP
Perhaps its only good feature was
sensitivity, while its worst aspect was
a very narrow, peaky, frequency response which resulted in a harsh metallic sound. Horn speakers were also
very fragile and just accidentally
knocking one onto the floor could do
considerable damage. Dangling wires
often resulted in a speaker being
tipped over.
A horn speaker can be described as
a large headphone with a trumpet or
sound horn atta~hed. In the majority
of cases, the driver is constructed in
exactly the same manner as a headphone but with the added refinement
of a variable air gap between the pole
pieces and the diaphragm. This adjustment can increase or decrease the
sensitivity, depending on whether the
pole pieces are brought closer to the
diaphragm or moved further away.
On strong signals, it can be necessary
to move the pole pieces further away
to prevent the diaphragm from rattling against them.
Horn speakers came in a range of
sizes and varied from quite small units
to large floor standing models nearly
one metre high.
Size did not make a great deal of
difference to performance and, generally, one horn speaker sounds much
the same as another. If there were any
notable exceptions, then I have yet to
hear them.
It's also worth noting that not all
horn speakers look like horn speakers. In some instances, manufacturers
built horns into timber or metal cabinets. Never assume that an old speaker
box contains a cone speaker. A close
inspection may reveal that there is a
horn speaker inside the cabinet.
Amplion Dragon
One of the most sort-after horn
speakers is the Amp lion Dragon which
a few Dragons around without their
drivers and I know of one particular
collector who is willing to pay up to
$100 for an Amplion driver to fit his
junior Dragon.
My situation had been the direct
opposite. I have had a Dragon driver
for some years and had been looking
for suitable parts in order to build up
a complete speaker.
The bits and pieces I had been seeking finally materialised recently when
I was lucky enough to obtain two
wrecked junior Dragons without drivers. Unfortunately, both flares were
damaged and the only way a complete speaker could be built was to
combine the undamaged segments of
each flare into one unit.
Soft iron strips hold the flare together. The oak veneer segments slide into slots
in the iron strips & are crimped at each end. An end tab is then folded over for
good measure. The oak segments are extremely difficult to remove without
damaging them.
comes in two sizes: junior and senior.
Naturally, the senior is the larger of
the two.
The appealing aspect of these old
Dragons is their timber flares. Most
horn speaker flares are made of spun
aluminium which, when painted, has
nowhere near the same visual appeal
of the Amplion Dragon, with its segmented oak flare.
Better tone
Old advertisements claimed that the
wooden flare produced a better tone.
Once again, if there is a difference,
then my ears cannot detect it. As far
as I am concerned, Amplions with
oak flares were no better sounding
than any other horn speaker from that
era. However, they were considerably
more expensive than some makes and
no doubt there was a bit of "snob
appeal" attached to owning one because they looked very stylish indeed!
Regrettably, the Amplion Dragons,
with their wooden flares, have not
survived the shipwrecks of time very
well. Although there are still a few
good examples around, the majority
are in poor condition. Whether Dragons or otherwise, most horn speakers
are nearly 70 years old and are showing their age.
Damp storage usually results in the
Dragon's plywood flare separating and
going out of shape. The thin soft iron
strips that hold the oak segments together can also give trouble and severe rust problems are difficult to
solve. What's more, natural rubber was
also used in their construction and
this too can cause problems when it
deteriorates and goes out of shape.
Rebuilding the Dragon
It seemed a simple enough task in
theory - just dismantle the flares,
pretty up all the usable bits and reassemble the pieces. Unfortunately, it's
not that easy in practice!
The oak flare on a Dragon speaker
is not easily dismantled. Each wooden
segment is crimped into position at
The underside of the base was coated
with felt to protect valuable furniture
from scratches - especially receiver
cabinet tops.
Driver attachment
This Amplion Dragon driver had been
in the author's collection of "junk" for
many years. It was still in working
order &, judging by the nameplate,
has had little use. Often, the dragon
emblem is damaged, due to finger
wear as the sensitivity control is
rotated.
The driver on a Dragon speaker is
attached to the horn by a rubber bush.
It is not uncommon for the bush to
perish away to almost nothing, leaving the driver separate from the rest of
the speaker. It is for this reason that
complete speakers in working order
are comparatively rare. There are quite
Any "back from the grave" restoration
of this nature requires a visit to an
electroplater. Re-nickelling helps to
bring back that as-new appearance
and is often an essential part of the
restoration.
FEBRUARY
1993
97
individual segments of the horn.
This was the case with my rebuild
and some of the lighter toned segments were touched up with oak wood
stain, making the overall appearance
of the flare a little more uniform.
I might add at this stage that working on the flare is a delicate operation
and one must be careful not to lift the
veneer at the .ends of the segments.
Old oak veneer is very brittle and
splintery and any loose ends need to
be glued down before working on the
flare. Each flare segment is made of
3-ply and this consists of two outside
layers of oak veneer, with another slither of timber in between. The overall thickness of the ply is only about
2.5mm.
A tedious task
The driver fits onto the end of the horn with nothing to hold it in place but the
friction of a rubber bush. As the rubber perishes, it loses its grip & the two
sections separate - one reason why so many Amplion Dragons now have no
driver attached.
.
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Stripping the flare back to bare
wood and metal proved to be a long
and laborious task. While some would
argue that the speaker's originality has
been ruined by doing this, one must
remember that I have combined parts
from three separate speakers in differing stages of disrepair. If the finished article is to have any appeal
whatsoever, then it must be refurbished so that it will look as though it
is a single unit.
Regrettably there are not enough
Amplion Dragons in good original
condition to go around and combining various bits and pieces was the
only way out of my dilemma.
Painting the metal strips that hold
the oak segments in place was also a
tedious job and calls for a steady hand.
The inside of the flare was particularly difficult to work on.
Semi-gloss finish
The electroplating included all nuts, bolts & washers. Attention to such details
enhance the overall appearance of the finished restoration.
the ends, which makes their removal
quite difficult. Great care is required
if the segments are to be removed
without damaging them.
Reassembling the flare also has its
problems because once the segments
have been removed they do not go
back tight enough to hold together.
They really need to be glued into place,
otherwise the reconstructed flare
keeps falling apart.
With my particular flare rebuild,
one flare had two segments replaced
with p1.eces from another flare. I would
98
SILICON CHIP
have preferred to completely strip the
flare but I didn't want to risk damaging the various pieces and have to go
through all the reassembly hassles.
Matching the segments
One particular problem when combining the flare segments of two or
more speakers is that they may not
match visually as well as they did
originally. The oak veneer doesn't all
come from the same oak tree. As a
result, there can be significant tonal
and wood grain differences between
When restoring an antique such as
a horn speaker, a much better effect is
obtained with semi-gloss finishes.
Painting it up so that it is all bright
and shiny really does spoil the illusion. A dull lustre is far more appropriate for antiques and a horn speaker
is no exception to this rule.
The timber flare was not the only
part of the speaker that required attention. The pressed steel horn was in
need of painting and all the nickel
fittings such as the base and various
nuts and bolts were packed off to an
electroplater to be "re-nickelled".
These metallic items looked particularly shabby and really needed the
full treatment.
Eventually, all the bits and pieces
were reassembled and I was rewarded
with an excellent example of an Amplion Dragon in working order. It was
well worth the effort!
A true collector's item
'
.
The finished loudspeaker, circa 1926. Many hours of work went into restoring
the oak flare and painting the metal strips that hold it together. Although horn
speakers are terrible things to listen to, this one is a true collectors's item.
It was fortunate that the driver I
have had for so long was in working
order and only required a coat of paint
to tidy it up. Some Amplion drivers
are not easy to dismantle as there are
no convenient screw heads to undo.
They seem to be sealed units that
were not meant to be tampered with.
Listening to the old Amplion confirmed my previous remarks. It sounded no better or worse than most other
horn speakers. However, its looks and
general appearance are far more appealing to the eye than most and that
is what the old Dragon is all about. It
is a collector's item in the true sense
of the term!
An interesting aspect of collecting
horn speakers is that although they
are primitive by modern standards,
they were the pinnacle of technological development at the time they were
made. Every invention has to start
somewhere and from that point on it
is gradually modified and improved
until technical excellence is finally
obtained.
For example, consider how much
sound recording and reproduction
equipment has improved since the
early days of the Edison cylindrical
gramophone. Likewise, the loudspeaker has gone through many stages
of development during the past 70
years.
One does not have to listen to a
horn speaker for very long to fully
appreciate just how much time and
effort has gone into loudspeaker development since the 1920s - a time
when the Amplion Dragon reigned
supreme.
SC
TETIA/MITSUBISHI ELECTRIC AWA
TECHNICAL LECTURES
13th and 14th March 1993
•
WMM,i ►iidW
Enjoy a weekend of informative technical lectures and exciting afterhours fun at the
luxurious WREST POINT Hotel/Casino. Subjects include VCRs, TVs, CDs, Fax,
microwaves & cellular telephones. Fares, accommodation, meals etc. are a legitimate
business deduction so why not take a tax free_Q~~ak aw8:_y from the routine?
Go on! Be a Devil!
- - , :::F= -- Contact Cliff Townsend, 27 Alma Road, Orford, Tasmania 7190
or phone him on (002) 57 1266.
FEBRUARY
1993
99
ASK SILICON CHIP
Got a technical problem? Can't understand a piece of jargon or some technical principle? Drop us a line
and we'll answer your question. Write to:Ask Silicon Chip, PO Box 139, Collaroy Beach, NSW 2097.
Valiant ignition
fights on
I have a query on the electronic
ignition circuits based on the Motorola
MC3334P which have been featured
in various issues of SILICON CHIP. I
need one for my own car. It is for a
Valiant which has a reliable system.
One only needs to change the plugs
when it gets hard to start on cool
mornings.
Anyway, the Chrysler unit uses a
TIV transistor and the sealant leaks
out in the hot weather and it draws
about 6A running - double the specifications. My question involves the
adaptability of the SILICON CHIP circuit to this one, in respect to the dual
ballast resistor which has an auxiliary resistor of 0.5.Q Does the SILICON
CHIP design use this auxiliary resistor
and does it sink the coil current in the
same way?
I would like to fit the Chrysler socket
Using the inverter
with computers
I have been reading with interest the articles on the 2kW inverter
that began in your October 1992
issue.
A couple of days ago, we had a
bad electrical storm . that passed
through the area where I work and
lightning struck a tree in the
grounds outside the building. It
blacked out our power for a few
seconds - just enough to send our
main computer system into a spin.
We are intending to purchase a
UPS for it but a unit that would
run our system for about 15 minutes will cost in excess of $4500 (it
takes that long to properly power
down our system). I was wondering how much modification would
need to be done to the inverter to
turn it into a UPS, as this project
would be a lot more viable for us
100
SILICON CHIP
on it so I'd have an emergency plug
when on long trips. (R. D., Darwin,
NT).
• Unfortunately, we do not have any
circuit information on the ignition
systems fitted as original equipment
to motor vehicles. The Chrysler system does appear to have used a sensing resistor to prevent the coil current
from exceeding a predetermined
value. In that respect, it is probably
similar in principle to the circuit suggested by Motorola for the Delco distributor. This circuit was featured in
the article on our reluctor-based high
energy ignition published in the May
1990 issue of SILICON CHIP.
Having said that, it may be possible
to adapt our circuit for use in the
Valiant system.
Generating 240VAC
in a remote area
The area that I live in is about 2km
and would easily run our computer system. (M. R., Toowoomba,
Qld).
• Essentially, the inverter could
be converted to function as an
uninterruptible power supply
(UPS) by providing an additional
circuit which senses mains drop
out and then switches over to the
inverter. The inverter could either
be run continuously or, if a longer
changeover period could be tolerated, the inverter could be switched on by the mains changeover
circuitry.
We do intend to do something
along these lines in the longer term
but have no plans to do it within
the next few months. Mind you,
by the time you build an inverter
and provide a decent battery bank
using explosion proof batteries,
you may well find that $4500 is
quite reasonable for the UPS you
require.
from the nearest power pole and to
have 240VAC mains installed would
be far too expensive. Because of this,
we have gone to an alternate lifestyle.
We run two battery banks of12V. Each
bank consists of two rows of six 2V
ex-Telecom batteries connected in series to give 12V, then hooked up in
parallel to give twice the amperage.
These batteries are charged via two
solar panels (one per bank of batteries) which on a good day can deliver
up to 4A per panel.
To assist charging in winter, we run
a generator. Not only does this generator assist charging but it runs a few
of our 240VAC appliances as well. I
am interested in the 2kW 24/240VAC
Sinewave Inverter featured in the October and November issues of SILICON
CHIP. My only concern is that this
inverter operates at a voltage of 24 V
rather than 12V. I would like to know
what I would have to do to change it
to 12V operation.
If this isn't worth doing, then could
you tell me of a circuit that could
regulate 240VAC at a reasonably high
amperage with any starting voltage,
as our generator is not regulated and
when the revs go up so does the voltage. Because of this, we have to set
the throttle at a certain point to give
us 250-260VAC, to allow for voltage
drop when a big load is connected;
eg, our washing machine.
If I had such a circuit, I wouldn't
have to worry about the starting voltage, or any high voltage that may damage our appliances (which has already
been done). When we bought our generator we were told that it was regulated but we found out that this was
wrong. The generator started putting
out in excess of 390 volts and destroyed. or damaged most of our
240VAC appliances. Any suggestions
would be greatly appreciated. (S. J.,
Walwa, Vic).
• It is not possible to modify the 2kW
Sinewave Inverter to run from 12V
without substantial redesign. Why not
use your existing battery bank in series rather than in parallel? You could
still use the same charging arrangement of one solar panel for each bank
of batteries. Better still, you could
connect the two solar panels in series
and use them to charge the whole 24 V
battery bank in one go.
We are surprised that your generator does not have sorne form of regulation which is usually achieved by
varying or rapidly switching the field
current. We are also surprised that the
revs can vary. Normally a 240VAC
50Hz petrol powered alternator is set
to run at a fixed speed which is close
to 3000 rpm (to obtain 50Hz). The
throttle is then automatically governed
to maintain the speed, regardless of
changes in the load. It seems possible
that you have been sold a "pig in a
poke". You should have it repaired or
replaced to avoid the risk of damaging your appliances again.
By the way, the 2kW inverter will
run a standard washing machine without any problems.
Confusion on diesel
sound simulator
With lightening heart, I read the
project article on the Diesel Sound
Simulator (SILICON CHIP, December
1992) only to conclude in a state of
confusion.
My problem is simple. I wish to use
the project in my radio-controlled
model boat. The heart of my boat is a
12V 35Ah lead acid battery, so finding a suitable power supply presents
no problems.
The drive system is two 12VDC
motors, independently controlled by
two reversible, resistive, variable
speed controllers. These each have a
maximum resistance of 15Q to drive
the screws at very slow speed. How
do I modify the input circuit to make
the Diesel Sound Simulator operate
in my boat?
Secondly, if I use the DSE K-2630
audio amplifier to drive a larger
speaker, will I have to modify the
existing audio amplifier circuit to suit
this external amplifier? (N. S., Coolbellup, WA) .
• This circuit should be adaptable for
use in your boat without any modifications - just connect the input across
one of the motors. In addition, the
existing small amplifier should be
quite adequate to drive a larger loudspeaker. In fact, we would suggest
that you try the circuit on its own
Solution to masthead
amplifier problem
a 1.SpF ceramic capacitor and what
had been an attenuator became an
amplifier.
I refer to the Masthead AmpliThis begs the obvious question:
fier, published in SILICON CHIP in if it's a design fault, what of the
August 1991 and the letter from R.
"many hundreds of kits sold"? Are
W. in June 1992. I too purchased
they relegated to many hundreds
one of these kits an d had precisely of junkboxes or are they being used
the same results as R.W.
in high-signal areas that benefit
Because mine was an awkward from an attenuator rather than an
mast to access and since we wanted amplifier? Or is there some pecuimmediate reception, I did the liar resonance problem with the
same as R. W. and purchased a kits purchased by R. W. and mycommercial unit, consigning the self, perhaps linked to station freqkit to the junkbox.
uency?
Some time ago, however, a friend .
Whatever the answer, I can only
required a masthead amplifier, so suggest that if anyone has one of
I decided to exhume the kit and these kits in the junkbox, they just
see if I could find out why it be- try the above modification. They
haved more like an attenuator than too might be pleasantly surprised!
an amplifier. All components ex- (R. R., Maclean, NSW).
cept the OM350 were either • We are very interested to learn
checked or replaced, to no avail. that you were able to make your
This only left the OM350 or a de- masthead amplifier operational by
sign fault.
discarding 14. In fact, if L4 can be
I was reluctant to purchase an- discarded, then you really should
other OM350 after reading of R. not need the 1.SpF ceramic caW.'s woes, so I took a closer look at pacitor either.
the schematic. With the limited
In answer to your obvious quesequipment at my disposal, it tion, we don't know how many
seemed that 14 (in the LT Telebrite other units would have the same
power supply unit) was highly sus- fault. However, any readers who
pect. This coil appeared to simply are experiencing problems with
shunt the signal to ground, so L4 this unit should try the same apwas discarded and replaced with proach.
before building or buying a larger audio amplifier.
If you do decide to run another
amplifier, you can leave out transistors Q2-Q5. The signal from the Diesel Sound Simulator is then connected
to the external amplifier from the junction of the 47kQ and 100kQ resistors;
ie, at the base of Q2.
of the Triac and its A2 electrode.
Notes & errata
Studio Twin 50 Amplifier, MarchApril, 1992: the power amplifier stages
can become unstable if the polyswitches (TH1) open due to overdrive
and disconnect the Zobel networks.
To prevent this, replace the two poly-
Are Triacs
equivalent types?
I have been supplied with a Q6040J7
Triac in place of BTA41 600 Triac.
Can this substitute be used and if so
what alteration is required to the circuit? Note: the physical difference can
be taken care of. (I. H., Killarney, Qld).
• The Q6040J7 Triac is a suitable substitute for the BTA41 and no alterations to the circuit are necessary. Note
that you should check that there is no
electrical connection between the tab
!\
+ GNO
GNO +
LEFT
RIGHT
OUTPUT
OUTPUT
switches on the PC board with wire
links and connect them instead between the outputs of the Zobel networks and the speakers. The above
diagram shows the wiring details. SC
FEBRUARY
1993
101
.......TCENrRE
Cash in your surplus gear. Advertise it here in Silicon Chip.
r-------------------------7
CLASSIFIED ADVERTISING RATES
ANTIQUE RADIO
Advertising rates for this page: Classified ads: $10.00 for up to 15 words plus 40
cents for each additional word . Display ads (casual rate): $20 per column
centimetre (Max. 10cm). Closing date: five weeks prior to month of sale.
To run your classified ad, print it clearly in the space below or on a separate sheet
of paper & send it with your cheque or credit card details to: Silicon Chip
Classifieds, PO Box 139, Collaroy Beach, NSW 2097. Or fax the details to (02)
979 6503.
ANTIQUE RADIO restorations. Your
one-stop radio repair shop. Specialising
in restoring vintage radios, including
chassis rewiring, re-condensing, quality
new parts, valves, valve sockets,
speakers, power & audio transformers.
Secondhand radio dials & parts for most
brands & models. About 400 radios in
stock for sale, restoration & parts. Every
restored wireless is covered by a 2year warranty on parts & labour. We
restore damaged woodwork & cabinets
& French polish (approx. 40 coats) .
Vintage car radios available for sale or
restoration. Repairs done on tape decks.
Open Sat. 10am-5pm; Sun. 12.30-5pm.
109 Cann St, Bass Hill, NSW 2197.
Phone (02) 645 3173 BH or (02) 726
1613AH.
FOR SALE
Enclosed is my cheque/money order for $._ _ __
D Bankcard
D Visa Card
D Master Card
or please debit my
XI
I
I
I
Signature_ _ _ _ _ _ _ _ _ __ _ Card expiry date_ _~/_ _ _
I
Name _ _ _ __ _ _ __ _ _ _ __ _ __ _ __ _ __ _ I
I
Street _ _ _ __ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ __
I
I
Suburb/town _ _ _ _ _ __ __ _ _ _ Postcode_ __ _ __
L _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ JI
Card No.
102
SILICON CHIP
WEATHER FAX programs for IBM XT/
ATs *** "RADFAX2" $35 is a high resolution, shortwave fax, Morse & RTTY
receiving program. Suitable for CGA,
EGA, VGA and Hercules cards (state
which). Needs SSB HF radio & Radfax
decoder. *** "SATFAX" $45 is a NOAA,
Meteor & GMS weather satellite picture
receiving program. Needs EGA or VGA
plus "WEATHER FAX" PC card. ***
"MAXISAT" $75 is similar to SATFAX
but needs 2Mb expanded memory
(EMS 3.6 or 4.0) and 1024 x 768 SVGA
card. All programs are on 5.25-inch or
3.5-inch disks (state which) & include
documentation. Add $3 postage. Only
from M. Delahunty, 42 Villiers St, New
Farm, Old 4005. Phone (07) 358 2785.
PAY ASIAN PRICES for common electronic components. No minimum. Ask
about hard to get items. Local SAE for
details. DIY Electronics, GPO Box 904,
Hong Kong.
FOR SALE: we have a number of
Plessey 2001 B-MAC satellite receivers for sale. This model is currently
retailing at over $2200.00. These are in
good going condition and complete with
SURPLUS COMPONENT SALE
STOCK QTYS LIMITED, NO BACKORDER$ .
2N3055
$1.20
RESISTORS
TIP30C
$0.50
MOST VALUES AVAIL.
TIP122
$1.20
1I4W MIFILM
$31100
2N7000
$1.50
113W CARBON
$21100
2SC2240
$0.60
112W CARBON
$41100
VN88
$2.00 ·
1W CARBON
$51100
3N170
$1.50
2W CARBON
$8/100
2N5954
$1.50
SW WIREWOUND
$0.30
2N3440
$1.20
10W RESISTORS
$0.60
2N4392
$0.50
100uF 10VTANT
$1.50
LM3900
$0.50
C&K 1201 SW
$0.50
27C41
$1.00
SW Oil SW
$2.00
68681
$7.00
CD22100 IC
$2.50
747CJ
$0.80
78L12, 79L12
$0.50
8251
$3.00
8259
$4.00
74122
$0.50
A25 THERMISTOR
$5.00
4520
$1.00
MCT275 OPTO
$1.20
74HC132
$1.00
MOC3020 OPTO
$2.00
74HC14
$1.00
MOC8050 OPTO
$1.50
4528
$1.00
74C161
$2.00
7417
$0.50
74HC74
$0.70
9602
$0.50
74S02
$0.70
PHONE OR MAIL ORDERS, CREDIT CARDS ACCEPTED FOR
ORDERS $20 & OVER, DISCOUNTS FOR QUANTITY ORDERS
SECONTRONICS
PO BOX 2215, BROOKSIDE, OLD 4053, PHONE {07) 355 1314
143 GRAYS RD, ENOGGERA, QLD 4051, FAX (07) 8551014
SHOP OPEN SATURDAY 9AM • 4PM AH (07) 8551880
MEMORY & DRIVES
Plans Kits and PCBs
PRICES AT DEC. 10TH, 1992
SIMM
1Mbx9
1Mbx 3
4Mbx9
4Mbx B
DRAM DIP
1 x 1Mb
256 X 4
41256
1Mbx4
70ns
70ns
70ns
80ns
$52
$48
$190
$174
70ns
70ns
80ns
(stat)
$5.50
$5.50
$2
$23
DRIVES
SEAG42Mb
SEAG89Mb
SEAG 107Mb
SEAG 130Mb
SEAG245Mb
14ms
14ms
15ms
12ms
12ms
$240
$310
$360
$398
$770
IBM PS.2
50/55170
70135
90/95
2Mb
4Mb
4Mb
$120
$210
$210
TOSHIBA
T3200SX
T44/6400
T5200
2Mb
4Mb
2Mb
$150
$300
$150
MAC
2Mb SI & LC
4Mb P'Book
$95
$245
PROCESSORS
INTEL 486DX2-66
INTEL 486 DX50
$950
$810
EPROMS
27C 256-150
$3
Sales tax 20%. Overnight delivery. Credit cards welcome.
Ring for Latest Prices
100W Valve Amp PCB ............................................... $30
Valve Amp PSU PCB ................................................. $25
Universal PSU (±5/±12V) Dual Supply ...................... $10
Digi 125100W amp/pair ............................................ $10
ETI 1623 PIA for PCs .............................................. $40
Max 1/0 Board ............................................................ $40
Max Kit ............
.. ............... $169
LM380 3.5 amp PCB ................................................... $7
AEM 35W amp kit ........ ................................ .. ........ $20
ETI Audio Toolkit PCB .............................................. $10
AGC Amp PCB ......
.. ................. $7
Z-80 Miniprocessor PCB ............................................ $50
6502 Miniprocessor PCB ......................................... $50
6809 Miniprocessor PCB ........................................... $50
8048/8049 Developers board complete B& T ........... $199
IBM PC Prototype PCB.................. .. ...................... $50
EPROM Programmer .............................................. $299
ESL-1 Electrostatic speaker kit/pair inc manual ...... $899
ESL-1 Assembly Manual ........................................... $50
P.C. Computers (08) 332 6513
36 Regent St, Kensington SA.
1st Floor, 100 Yarrara Rd, PO Box 382, Pennant HIiis, 2120.
Tel: (02) 980 6988
Fax: (02) 980 6991
PELHAM
FIX-A-KIT
KIT REPAIR & CONSTRUCTION
remote controls and handbooks. If interested, please make a cash or Bankcard offer to: Long ridge Electronics, PO
Box 290, Norfolk Island 2899, or fax to
(0011) 6723 22833.
THE HOMEBUILT DYNAMO: (plans)
brush less, 1000 watt at 740 revs. $A85
postpaid airmail from Al Forbes, PO
Box 3919 - SC, Auckland, New Zealand. Phone Auckland (09) 818 8967
anytime.
KIT REPAIRS & Construction Service.
Fixed price servicing for all kits. No job
too small. Ph (02) 649 2134 after 5pm.
COMPONENT PACKS, 30 trimpots,
Bourns, Beckman etc, mixed values
and types including multiturn. 400 metal
film ¼W resistors, most are 1% or 2%
Beyschlag, mixed values including
some E96 and E192 series. 200 carbon film ½W and 1W resistors, most
are Beyschlag 1% or 2%. All component packs $12 ea plus $5 p&p. Japanese transistor pack with two each of
2SA1069,
2SC923,
2SC1826,
2SC3157, 2SD381, 2SD667, $15 per
pack. Electronic component pack, 400
items including ICs, transistors, diodes,
resistors, trimpots, capacitors, relays,
fuses etc. All new components, $25 per
pack, plus $8 p&p. Valves, CV3998, ·
12AX7, 12AY7, 12BY7A, 3A4, 6AM5,
6J7G, all $8 each or 10 for $70 (can be
mixed). Open Thursday, Friday 4pm8pm, Saturday 9am-4pm, 143 Grays
Rd, Enoggera, Old. Ph (07) 355 1314
or (07) 855 1880 AH. Fax (07) 855
TRANSFORMER REWINDS
3 MONTHS WARRANTY ON REPAIRS
12 MONTHS WARRANTY ON CONSTRUCTION
TECHNICAL ASSISTANCE
ALL TYPES OF TRANSFORMER REWINDS
HVCAL ELECTRONICS
TRANSFORMER REWINDS
Design. Manufa cture & Re p a i r of El e ctro n ic
Reply Paid No.2, PO Box 438, Singleton, NSW
2330. Ph: (065) 761291. Fax: (065) 761003.
1014. Visa, Bankcard, Mastercard available for fax or phone orders over $20.
Secontronics, PO Box 2215, Brookside,
Old 4053.
8061 MICRO-COMPUTER PROTOTYPING PCB $30 - similar to my
ROMLoader EA Jan 92. Provision for
8255 PPI, 9346 EEPROM, 2k-32k
SRAM, 2k-32k EPROM, MAX232, DIP
switches & expansion header. Send A4
SAE for article. Tantau, PO Box 206,
Gordon 2072.
AMSTRAD NOTEPAD info disk. IBM
720K format. Includes expansion software drivers and circuits, a full map of
all Port addresses, and a short machine language tutorial on the inbuilt
Z80 Assembler. $15, or free with the
purchase of a unit at $390 incl. post &
ins. For promo disk, send a $1 stamp to
[---------~=-;
INTELSTAT - International Satellite (Television) Receiving System (movies,
sport, news). Commercial 4.8-metre
solid dish plus system electronics package. Can see operating. $3995.00 ono.
Phone Rod (08) 387 03-Z:2.
Equipme nt
(02) 633 5477
Don McKenzie, 29 Ellesmere Crescent,
Tullamarine 3043. Phone (03) 338 6286.
MUSIC ON HOLD KIT: SC Sept.1990.
This unit is simply connected across ·
the existing telephone line. Press the
"Hold" button and your caller will have
music on hold, press the release button
to restore the conversation. Captures
the line when activated and an inbuilt
pulser and a flashing LED remind you
that the hold function is activated. Will
even release the line after a few minutes in case you forget that you left
somebody on hold. Just add an inexpensive radio for a complete system.
The radio is switched by this unit to
conserve its batteries. On special at
$30. For the complete kit without the
case, 12V DC plugpack: $12.00. Cat
No GK116. * 16 CHANNEL UHF REMOTE CONTROL: see EA Nov 88-Jan
89. One transmitter kit, one receiver kit,
& one 4-channel relay driver kit, priced
to clear •at a total price of $99. Ref
XXFEB9401 . * 1-inch CRO TUBE: new
1-inch CRO tube, plus a connecting
diagram, plus a simple experimental
circuit. Very limited quantities: $30. Ref
XXFEB9402. * FIBRE OPTIC CABLE:
high quality fibre optic cable, single
fibre <at> $2/metre or 10 metres for $15,
dual fibre <at> $4/metre or 10 metres for
FEBRUARY
1993
103
*
JV Tuners - Repairs
Tuner
•
•
•
•
repairs for T\'s & \'CRs
Shorted Turns Tester
High \'oltage Probe
Degaussing \\'and
Remote Control Tester
*
(02) 7741154 Fax (02) 7741154
Transfonner Rewinds
Advertising Index
Altronics ... ....................... ...... 52-53
For all t~ pes of
transformer rewinds.
Antique Radio Restorations ..... 102
(065) 761291 Fax (065) 761003
Autotron Australia ............ .... ...... 41
A-One Electronics ................ 60-63
Av-Comm .... .......... ..................... 59
Breakthrough Computers .. .. ...... 49
Ian J Truscott's
Electronic World
EEM Electronics
\!ail or credit card facilities
Printed drrnit hoard assembly.
s11itchmode pm1er supplies repaired.
Design 1rnrk from start to finish.
Ring anytime 9am-9pm \Ion-Sun.
(03) 7233344 Fax (03) 4192808
(OJ) 4011393
For sen ice ~'\; re1rnir work
David Reid Electronics ............. ... 5
Dick Smith Electronics .......... 10-13
EEM Electronics ..... ................ . 104
Electronic World ................. 77,104
Emona Instruments ................... 67
Ford Motor Company ............ OBC
Harbuch Electronics .................. 76
$30. Ref XXFEB9403. * SWITCHED
MODE POWER SUPPLIES: compact
enclosed ex-Telecom supplies. Dimensions: 300 x 90 x 180mm. Unregulated
input: 30-50V, regulated input of 12V<at>
6A or 5V <at> 40A; two different units.
Limited stocks <at> $28 ea. P&P $7
(Heavy!). Specify type when ordering.
Ref XXFEB9404. * SOLAR LIGHTING
BARGAIN: (EA Nov. 92). This kit has
three separate sections that are contained on one PCB b!,.lt can be separated: (1) a crystal locked ultrasonic
movement detector, (2) a fluorescent
tube inverter (4-20W) with logic circuitry,
(3) a solar battery charging regulator &
an incandescent lamp switcher-pulser,
which employs a Mosfet switch. As a
package special, we are offering the
complete kit for the three sections plus
six 6V/1 W solar panels for a total cost
of only $99 ! Ref XXJAN93104.
* SWITCHES: high quality miniature
enclosed, Italian (FEME) 1, 2, 3 & 5pole, 12-position switches: $2.80 ea or
10 for $20. Ref XXJAN93105. Major
cards accepted with phone & fax orders. Total cost of certified p&p: Australia $5, NZ (airmail) $10. Oatley Electronics, PO Box 89, Oatley, 2223. Phone
(02) 579 4985. Fax (02) 570 7910.
MICRO-ELECTRONIC ENGINEER: a
Sydney-based computing technical
company wishes to permanently appoint a micro-electronics engineer to
provide technical support and to develop new products for export markets.
Duties will involve to diagnose and repair MP based PCBs (component level);
to design and debug MC interface driver
using AL & C; to undertake research on
the application of MP controlled elec-
104
SILICON CHIP
T. A. Mowles
Printed cirrnit hoards for the
hohh~ ist.
For sen ice & enquiries contact:
Hycal Instruments .... ... .. ... ........ 103
Jaycar ... .. .. .... ..... . 33-36,69-72,IBC
JV Tuners ................................ 104
Kalex .......... .............................. . 51
Oatley Electronics ......... 44-45, 103
(08) 3265590
PC Computers ......................... 103
Pelham ............................... 31,103
tronic equipment; to liaise with manufacturers in H.K. & Taiwan. The ideal
person must have:* tertiary qualification
in electronics engineering;* advanced
skills in electronic hardware (analog &
digital) and software (AL & C): * at least
5 years exp. in MP based hardware
service, software design and network
support; * initiative to work independently and ability to train staff; * proficiency in English and Mandarin; * a
member of ACS, IREE or IEAust preferable. Salary range $32,000 - $38,000
p.a. Please send written application with
resume and reference to: Managing
Director, Keap Technology P/L, PO Box
1604, Chatswood, NSW 2067.
Peter C. Lacey Services ............ 64
Philips Test & Measurement ...... 87
Plough Book Sales .................... 51
RCS Radio .............................. 104
Resurrection Radio .................... 77
Rod Irving Electronics .......... 90-95
Scan Audio .. .... .......................... 23
Scientific Devices ...................... 75
Silicon Chip Binders .................. 30
Silicon Chip Back Issues ...... 54-55
T. A. Mowles ............................ 104
Technical Applications .......... .. ... 43
Tektronix ....... ............................. 79
Tetia ...... .. ................................... 99
Transformer Rewinds .............. 104
RC§ RADIO PTY LTD
~
"ifr1ffi
RCS Radio Pty Ltd is the only company that manufactures and sells
every PC board and front panel
published in SILICON CHIP, ETI and
EA.
RCS Radio Pty Ltd,
651 Forest Rd, Bexley 2207.
Phone (02) 587 3491
PC Boards
Printed circuit boards for SILICON
CHIP projects are made by:
• Jemal Products, 5 Forge St,
Welshpool, WA 6106. Phone (09)
350 5555.
• Marday Services, PO Box 19-189,
Avondale, Auckland, NZ. Phone (09)
828 5730.
• RCS Radio Pty Ltd, 651 Forest
Rd, Bexley, NSW 2207. Phone (02)
587 3491.
''BELLMATE''
BURGLAR
ALARMS
Jaycar Electronics is proud to announce a new range of high quality, feature packed low
priced home/ office/warehouse burglar alarm equipment. The Bellmate range is solely represented in
Australia by Jaycar. This means that the middleman has been eliminated and that saving is
passed on to our customers. They are only available throughjaycar Electronics,Jaycar Dealers &Jaycar
appointed installers. The Bellmate range includes: • 3 Alarm Control Panels • 2 Remote Keypads
• 3 Passive lnfrared Detectors. See our catalogue in March '93 for all the details.
BELLMATE 950
4 SECTOR PROGRAMMABLE
CONTROL PANEL
BELLMATE 1000
8SECTOR
PROGRAMMABLE
CONTROL PANEL
This will be available mid February.
If you compare features per dollar, we
believe no other alarm panel comes
near. Features
include:
• Keypad controlled
• Easy to programme
• Heavy duty 1.5mm
thick painted steel
cabinet • 4 zones
• 24 hour zone
• Lockout if incorrect
access codes used
• Split end of line
resistors • 3 sound
panic sirens
• 1 year warranty
• Plus more.
CAT. LA5320
This panel
incorporates they
very latest in alarm
technology. Look at
the features:
• 8 programmable
zones plus tamper
and panic • Each of
the 8 zones can be
programmed to any
I
of the 6 options instant, 1st delay,
2nd delay,handover,
24 hour, two trigger
• Can have silent
alarm if a telephone
dialler is used
• 4 separate tampers
on panel • Split end
of line resistors
BELLMATE 100
•
Plus all the
BELLMATE 100
PASSIVE INFRA
BELLMATE 1000
BELLMATE 950
features of the
RED DETECTOR
4 sector. See our new catal~ e for
Watch out for the two new pairs
The "I 00" incorporates the latest
available
shortly.
The
Bellmate
200
at
full
details. CAT LA 5324
design features which offer total peace
$34.95 and the top of the line 300
INTELLIGENT
of mind to the end user, and few
at $69.95
<A ,. .
REMOTE
i'~:;., -r ·:.:,i
return calls for the installer. It has
.. , .
KEYPAD
'II,\;,
ei;1
switchable pulse count operation with
BELLMATE
·
,.,r
~,~.., ~··
single pulse and three pulse trigger
960 KEYPAD
I
FOR 1000 The keypad looks exactly
which virtually eliminate false alarms.
This keypad will remotely control
like the control panel on the 1000
See new catalogue for full details.
the 950 and 1000 panels.
alarm. From the keypads you can arm
Two year warranty. CAT. LA5016
and disarm the alarm and fully
CAT. LA5321.
prog:amme it. CAT. LA5325.
-------------
I
$149
229
$49.95
MAIL ORDER VIA ~
FREE CALL FOR ORDERS ONLY
(008) 022 888
HOTLINE (02) 743 6144.
~
-
-~
II
=·~
s
I'
"I
-.:::.:..._)
V/S4
fit:1,:ri!n
$50-$99.99 $6.50
OVER $100 $8.00
$49.95 .
~tl~o~~~:~~ncord 2137
ROAD FREIGHT ANYWHERE IN
AUSTRALIA (up to 20kg) $13.50
$55
i• ~,
0
:Et!:s
Rhodes 2138. ~ • ~ ~,
Telephone (02) 743 5222.
"'... ■- , -
t~:::
Fax (02) 743 2066.
:t.
iL
1
ADELAIDE SA 190 Wright St (Cnr Selby St) (08) 231 7355. Mon-Fri 9-5.30 Fri 8.30-Sat 9-12. BURANDA QLO 144 Logan Rd (07) 393 Om
Mon-Fri 9-5.30 Thurs 8.30-Sat 9-4. COBURG VIC 266 Sydney Rd (03) 384 1811. Mon-Fri 9-5.30. Fri 8.30-Sat 9-4.
MELBOURNE CITY Shop 2, 45 A'Beckett St City (03) 663 2030. Mon-Fri 9-5.30 Fri 8.30-Sat 9-2.
SPRINIVALE VIC 887-889 Springvale Rd Mulgrave (03) 547 1022. Nr Cnr. Dandenong Rd. Mon-Fri 9-5.30 Fri 8.30 - Sat 9-2.
SYDNEY CITY 129 York St. (02) 267 1614. Mon-Fri 8.30-5.30 Thurs 8.30pm - Sat 9-4.
BANKSTOWN 363 Hume Hwy Cnr Meredith St (02) 709 2822. Mon-Fri 9-5.30 Thurs 8.30pm - Sat 9-4 - Sun 10-4pm.
GORE HILL 188 Pacific Hwy (Cnr. Bellevue Ave) (02) 439 4799. Mon-Fri 9-5.30 T~urs 8.30 - Sat 9-4pm.
PARRAMATTA 355 Church St (Cnr. Victoria Rd) (02) 683 337Z Mon-Fri 9-5.30 Thurs 8.30pm - Sat 9-4pm. Sunday 10am-4pm.
PENRITH 199 High St. (047) 21 833Z Mon-Fri 9-5.30 Thurs 8.30 - Sat 9-4pm Sun 10-4pm. RHODES 6 Leeds St. (02) 743 5222. Mon-Fri 9-5.30.
|