Advertising Index
Altronics.................................27-30
Control Devices............................. 9
Dave Thompson........................ 111
Digi-Key Electronics...................... 3
element14..................................... 7
Emona Instruments.................. IBC
Hare & Forbes............................. 13
Jaycar.........................IFC,11,39-40,
..................................... 50-51,59-61
Keith Rippon Kit Assembly....... 111
LD Electronics........................... 111
LEDsales................................... 111
Microchip Technology.................. 5
Mouser Electronics..................OBC
Ocean Controls........................... 10
SC Pico BackPack.................... 105
SC SMD Test Tweezers............ 110
SC USB Cable Tester.................. 79
Silicon Chip Binders................ 111
Silicon Chip Shop............ 106-107
Silicon Chip Subscriptions........ 93
The Loudspeaker Kit.com.......... 91
Tronixlabs.................................. 111
Errata and Next Issue
Wagner Electronics..................... 12
112
Where to get inductors
for Battery Zapper
I want to build the Lead-Acid Battery Zapper & Desulphator Mk.3 (July
2009; siliconchip.au/Article/1500),
but both kits have been discontinued,
and the specified 220μH and 1mH aircored inductors are no longer available from Jaycar. Do you know where
I can get them?
● You have a few options. Air-cored
inductors are often used for crossovers,
and ‘crossover inductors’ are available
from other sources.
The Jaycar inductors used 20AWG
wire (0.8mm diameter). We found an
Australian website called Speakerbug with 220μH and 1mH air-cored
inductors at reasonable prices, wound
with either 18AWG or 21AWG wire.
18AWG would be preferable, but
either should work; see: siliconchip.
au/link/abex
Another option would be to wind
your own. There are online calculators that tell you how many turns of
what diameter wire on what sized
former are needed to make a specific
inductance value. If you have an LC
meter, you can also keep winding
until you reach the desired inductance value.
You might even find that reels of
enamelled copper wire have close to
the correct inductance by just using the
whole reel or unwinding a part of it.
We used that approach in the Easyto-build Bookshelf Speaker System
(January-March 2020; siliconchip.au/
Series/341), which used reels of ECW
as 390μH and 900μH inductors.
900μH is probably close enough to
1mH for the Battery Zapper, and for
the 220μH inductor, you could use
the same reels of ECW that measured
390μH for the Bookshelf Speakers but
MOS Air Quality Sensors, June 2022: in the Useful Links box, the secondlast link should be https://fs.keyestudio.com/KS0457
Railway Semaphore Signal, April 2022: be aware that some vendors
are selling DF9GMS-360 360° servos under the same model code as the
DF9GMS 180° servos specified for this project. The 360° servo motors will
not work. You need to use a 180° servo.
High Power DC Motor Speed Control, January & February 2017: the
IPP023N10N5AKSA1 Mosfets specified are currently unobtainable.
Constructors can substitute the FDP2D3N10C, which is available at the
time of writing.
Next Issue: the August 2022 issue is due on sale in newsagents by
Thursday, July 28th. Expect postal delivery of subscription copies in
Australia between July 27th and August 12th.
Silicon Chip
Australia's electronics magazine
unwind some turns (probably about
1/3 of them) to get a value closer to
220μH.
MC34063 regulator
chips failing
I have just built the Pocket TENS
Unit (January 2006; siliconchip.au/
Article/2532), and I have had problems with the repeated failure of the
MC34063 chip. When setting the
inverter output voltage, the IC fails. I
can get the output close to 60V before
that happens.
I got the MC34063s from eBay. As
for the toroidal transformer, I could
not find the original Neosid core, so I
used another of unknown origin but
with the same physical dimensions.
Do you have any ideas? (M. A., Wurtulla, Qld)
● The MC34063 is generally very reliable, but it is a ubiquitous chip, and
we suspect there are plenty of clones
on the market, some of which might be
dodgy. We suggest trying an MC34063
from Jaycar (Cat ZK8837) or Altronics
(Cat Z2750). For the ferrite core, use
Jaycar Cat LO1234. Those combinations seem to be reliable.
High voltage track
clearances
I designed a new PCB for the Multi
Spark CDI System (September 1997;
siliconchip.au/Article/4837) with a
full ground plane and am having some
problems.
Would a ground plane cause any
problems? I set the track clearance at
0.305mm. Do you think that’s enough?
(J. M., New Haven, USA)
● For tracks with up to 300V between
them, more clearance would be preferable. Arc-over would be likely at
0.305mm, especially without a solder mask layer. The IPC-2221 standards require 1.25mm or more (see
www.smps.us/pcbtracespacing.html).
Clearance may not be your only problem, though, and maybe photos of the
PCB could help us see where problems
might lie.
Note that we published a CDI
design much more recently (December 2014 & January 2015; siliconchip.
au/Series/279), and we can supply
both the PCB and hard-to-get parts for
that project. These are available from
our website at: siliconchip.au/Shop/?
article=8120
SC
siliconchip.com.au
