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Items relevant to "Power Supply for Battery-Powered Vintage Radios":
Items relevant to "Dual Battery Lifesaver":
Items relevant to "A Closer Look at the RCWL-0516 3GHz Motion Module":
Items relevant to "Balanced Input Attenuator for the USB SuperCodec, Part 2":
Articles in this series:
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Items relevant to "Infinite impedance AC source":
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Items relevant to "Flexible Digital Lighting Controller, part 3":
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Purpose of indentations
in some mains plug pins
I was very interested in the article
on the development of the Australian
three-pin plug and its history by John
Hunter (September 2020; siliconchip.
com.au/Article/14573).
But something I have always wanted to know is why the pins on some
plugs (especially the older ones) are
indented and not just flat?
By the way, I really enjoy your great
mag. which turned up here in Germany right on time. It seems the post is
now back to normal. (C. R., Tuebingen, Germany)
• John Hunter replies: I used to think
the indentations in some sockets were
for pin retention. However, in the hundreds of ancient sockets I have examined, I haven’t found any evidence of
that. All of them have the plain folded flat contacts; the same type still
used today.
Also, if such an arrangement did exist, it would be problematic with pins
having straight sides, since the contact
area would be reduced.
As a general observation, that indented side pin shape began to be discontinued in the 1950s, first by HPM,
then later by Clipsal. I haven’t found
any similar arrangement in US-made
sockets, which would mate with the
holes in the ends of their plug pins.
I did once see a vague reference that
the holes were to keep the pins in position whilst the plug was moulded
around it during manufacture. A few
Australian (notably CMA) plugs also
had these holes, so if there is some
truth to it, perhaps the indented sides
were for the same purpose.
Odd electrical sockets
on GPOs
I just read the article on the History
of Australian GPOs (September 2020;
siliconchip.com.au/Article/14573) –
what a fascinating article!
He did not show a four-pin socket,
but I have a photo of one that I took at
siliconchip.com.au
Lanacks Castle, Dunedin, NZ when I
took a tour through it. It was in a small
room behind a rope and was not in
use. The Castle guides did not know
anything about it, nor what the house
voltage was at that time.
The castle was built in about 1910,
and most of it was imported, including the electrics. It is a GEC 230V 10A
USA socket, but it might have come
from England as most of the castle
came from there.
I have asked electrical inspectors
from both England and New Zealand
about it. I was an Inspector before I retired a few years ago. Can you help to
identify it? (P. J., Auckland, NZ)
• John Hunter responds: I am familiar
with that socket and have one in my
collection. It’s designed to take the normal US blade plug with two parallel
pins, as well as the ‘tandem’ type plug.
The tandem plug went out of fashion early on, to be replaced entirely
by the common parallel blade type. It
did reappear later, but with an Earth
pin, and these days is used for 240V
appliances in the USA. You can see
the pin pattern at https://w.wiki/jsm
want to build the Balanced Attenuator
later). (O. A., Singapore)
• Phil Prosser responds: you certainly should not be able to hear any
hum. Check the voltage levels at the
ADC inputs, at pins 17, 18, 29 and
20. These should all be close to 2.5V.
Then follow the signals back through
the buffer; check pins 1 of IC2a and
IC4a. These should have a DC offset
of 0V. Similarly, IC2b and IC4b pins 7
ought to have 0V DC offset.
Are the 10µF capacitors on pins 3
and 5 of IC3 and IC5 in the right way
around? Check all your solder joints
carefully, since a bad (high-resistance)
joint could explain your symptoms.
That ADC is excellent. When you
find the bug, you should have a super
hifi ADC and the makings of an awesome piece of test kit.
Editor’s note: O. A. traced the fault
back to a bad solder joint on pin 3 of
the ADC chip. Pressing on the chip
affected the hum level, and reflowing that pin completely eliminated it.
USB SuperCodec
hum problem
The Colour Maximite 2 is another great project (July-August 2020;
siliconchip.com.au/Series/348). I managed to get it up and running after a
brief problem with the VGA connector
(no video output). I believe the connector holes are a little too large, so solder can wick in and wet the pin and
via without forming a bridge, unless
you use a lot more solder than usual.
After fixing that, I found a couple
more strange things. Firstly, when I
plug in my Microsoft wireless keyboard, everything works OK except
that the “<at>” and “:” characters were
once transposed (don’t ask me how
long it took to find this…), but on other
sessions, remained good.
Secondly, I have the latest version of
Tera Term, but the connection is very
“flaky”. It only connects about 1 in 10
attempts, sometimes displays graphics
characters at start-up, and is prone to
hang mid-sentence on occasions when
After I finished building the USB
SuperCodec (August-September 2020;
siliconchip.com.au/Series/349), I tested the DAC section on my amplifier,
and it works very very well. It’s crystal clear!
I also tested the ADC. It works, but
I have some hum in the background.
I can adjust the input level to make
it inaudible, but then when I feed it
with the DAC output, I cannot hear
the music (even if I set the volume
to its maximum on the PC). The only
way is to increase the input level,
but then the hum and music are superimposed.
I noticed that the +9V rail is +8.25V
and the -9V rail is -8.2V. But since the
DAC part works, I don’t think that’s the
problem. I soldered the USB Streamer,
but only the six pins that are needed (I
Australia’s electronics magazine
Colour Maximite 2
queries
December 2020 107
entering commands (yet, the direct
keyboard connection remains good).
Another surprising thing – when I
“Restore Setup…” in Tera Term, it never gets the saved serial port correct – I
have to go back in and set the correct
serial port. (I. T., Duncraig, WA)
• The swapped characters (“<at>” and
“:”) are probably caused by the keyboard being set to the wrong language
in MMBasic. Try entering OPTION
USBKEYBOARD US at the command
prompt (this option is saved so it will
be remembered on reboot).
As for your connection problems,
assuming you have checked all the
solder joints, the other likely cause
is that the PC or laptop does not have
the grunt to supply the approximately
200mA required by the CMM2. This
can be tested by using a high-capacity
USB charger to power the CMM2; if
everything works OK, that points to a
power supply issue.
Another possibility is that the USB
cable is faulty. We have found that
about ¾ of problems with the CMM2
can be traced to either a bad power
supply or a faulty USB cable.
ADF5355 DDS module
output is noisy
I have been testing the ADF5355
13.6GHz Touchscreen Frequency Generator (May 2020; siliconchip.com.
au/Article/14437), and noted that
the output signals are not as clean as
those from other units (based on the
ADF4351 and MAX2870).
Some people online have attributed this behaviour to noisy and cheap
voltage regulators used in the cheap
ADF5355 boards. I have ordered a few
daughter boards from Brian Flynn GM8BJF that use voltage regulators with
significantly lower noise (ADM71503.3 and ADM7150-5.0). These are
not cheap in small quantities (<1000
units).
Did you also note that the ADF5355
board was also ‘noisy’, which the engineering chaps call “phase noise”?
This was not mentioned in the May
2020 article.
I looked at the output signals over
the range of my spectrum analyser
(3.2GHz) and noted that the ADF4351
(two versions available from BangGood – TFT/OLED) and the MAX2870
produced very clean signals. (S. G. E.,
Hackham West, Vic)
• We did not measure the phase noise
108
Silicon Chip
of that unit because, for hobbyists who
need a sweep generator to test performance such as the frequency response
of filters, cables etc, phase noise is not
so important.
We used a 5V lab supply to power
our device, and did notice that the signal was somewhat noisy, but we were
not too critical because we did not expect the world for $280!
For your application where you
need a pure signal at a fixed frequency,
the changes you highlighted seem like
a good way to improve the power supply and vastly reduced phase noise.
We did check the unit’s harmonic
distortion up to 20GHz, because this
is one of the most essential factors to
produce signals that do not cause interference in higher bands. We found
the unit to be well within the specifications of the AD5355 with –33dBm
distortion at 19.9538GHz.
It seems like a lot of work to improve
the module, but as long as a good 5V
supply is used, it still gives a creditable performance.
2003; siliconchip.com.au/Series/293)
says that its power supply can deliver a peak current of around 40mA at
265V DC.
The 2016 valve supply has no details of its current delivery capabilities,
can you tell me what it can deliver?
I’m studying the design of boost converters and flyback converters so any
help would be most appreciated concerning this topic. (J. H., Scotland, UK)
• The January 2016 Stereo Valve
Preamp states (p33, right-hand column) that the power supply is purposefully designed to operate at its
current limit while supplying the anode current for the two 12AX7 twin
triodes. If you calculate their current
draw using Ohm’s Law and the values
given on the circuit diagram, that is a
total of around 4mA.
It’s probably possible to modify the
supply circuitry to deliver more than
that, but as it was adequate for that
particular design, we didn’t test it to
see how much current it could deliver at 265V.
Finding LCD for Reflow
Oven Controller
Identifying SMD
TVS cathode
I am getting together all of the parts
to build the DIY Reflow Oven Controller (April-May 2020; siliconchip.com.
au/Series/343). I am struggling to find
an LCD screen based on the KS0108
controller (looking in the source code
shows that the driver is for this chip).
As far as I can see, Altronics do not
have anything suitable, and Jaycar
only has an ST7920-based board
(XC4617). (S. G., Thurgoona, NSW)
• Phil Prosser responds: I bought mine
from eBay where they are prevalent
and usually very cheap. A search for
“KS0108 LCD” gives many results,
mostly at 128x64 resolution. The
choice of white on blue or black on
green is up to you, but we find the
blue ones have better contrast. I have
not had any problems with them from
that source – either they are not worth
faking, or the fakes work well.
In 2018, I bought two kits for your
Mini 12V USB Regulator (“Install USB
Charging Points In Your Car”, July 2015;
siliconchip.com.au/Article/8676). I
built one at the time but without success (I hadn’t mastered soldering very
small SMDs).
With COVID-19 shutting down New
Zealand, I decided to give the second
kit ago with some success, having gotten much better at soldering the very
small SMDs (using solder paste and a
hot air rework station).
You’ve explained how to orientate
the SMAJ15A and SK33A parts by
identifying a stripe on one end of each
these. I have had no trouble finding the
stripe on the SK33A, however, even
with a very strong light and magnification I can’t find one on the SMA15J.
With the body of the part orientated so that it is taller than it is wide, I
can read some text which says “BM”
and then below it, “4LZEO”. Above
the “BM” is what looks like a company logo. Is this enough information to
figure out which way around it goes?
(R. K., Auckland, NZ)
• Unfortunately, there are multiple
manufacturers of the SMAJ15A, and
they use different marking schemes. So
it helps to know who made the part to
Switchmode power
supplies for valves
I built the power supply for the
Stereo Valve Preamplifier (JanuaryFebruary 2016; siliconchip.com.au/
Series/295) on a small PCB to experiment with valve circuits.
The Valve Preamp article (November
Australia’s electronics magazine
siliconchip.com.au
figure this out. I checked our records to
see which exact part we purchased for
these kits, and it turns out it was Littelfuse. Here is their data sheet for that
part: siliconchip.com.au/link/ab5p
That shows that BM is the correct
marking. 4LZEO is the date and batch
code. With the writing orientated so
that you can read it, the cathode is at
the top. So, in other words, the Littelfuse logo marks the cathode. You can
also check this with a DMM set on diode test mode. You should get a reading of 0.6-1.0V with the red probe to
the anode (bottom) and the black probe
to the cathode (top).
Questions about
Motor Speed Controller
I see in the Notes & Errata published
in the September 2020 issue that you
have recommended a replacement for
the obsolete IGBT used in the 230V
10A Universal Motor Speed Controller (February-March 2014; siliconchip.
com.au/Series/195).
However, unlike the original device,
the replacement does not have an inbuilt reverse-polarity protection diode. Would that be a problem?
Secondly, I am puzzled as to the reason for having the motor on the IGBT
side of the bridge rectifier. No explanation for this is given in the article.
If the motor were placed inline with
the Active connection on the mains
side of the bridge, the motor would
see a more-or-less normal mains waveform, albeit PWM chopped. As you
have it, the motor is effectively subject
to rectified DC but with 100Hz ripple. I
wonder if there may be some instances
where that could cause problems. (D.
S., East Melbourne, Vic)
• The lack of a reverse diode within
the IGBT between collector and emitter is not important in that motor controller since current does not flow in
that direction in our circuit. There
does need to be a diode between the
positive supply and the IGBT’s collector to protect against over-voltage
when the motor is switched off; hence,
our inclusion of diode D1.
The motor could be placed inline on
the Active side of the bridge rectifier,
with the collector of the IGBT connected to the positive rectifier output. But
it would be very difficult and expensive to include over-voltage clamping
to protect both the rectifier bridge and
IGBT when the IGBT is switched off.
siliconchip.com.au
This protection would require two
inverse-series-connected high-current
zener diodes across the motor, or a
similar clamping circuit that would
be reliable. Since the motor controller is for universal motors that run on
DC or AC, there is no problem running
the motor with pulse-width modulated
pulsating DC, as we have done.
Running 250W Class-D
amp from a car battery
The local boys have had me build
numerous Silicon Chip 250W ClassD amps (November-December 2013;
siliconchip.com.au/Series/17) from
Altronics K5181 kits for their cars. I
have made it clear that they have to
find power supplies to drive these
amps to their full potential.
After constant hounding by the natives, I have been looking at the constant voltage DC-DC converters available from Wish, AliExpress etc and
am finding this very much out of my
league. Can you find a converter which
would suitable to power the 250W
Class-D amp to its maximum or close
to it, in a car? (J. C., Pialba, Qld)
• We published a DC-DC Converter
for the Class-D amplifier (May 2013;
siliconchip.com.au/Article/3774), but
it is not sufficient to get the full 250W
from the amplifier. It will produce up
to 125W into 4W on program material.
You would need two converters for a
stereo amplifier.
For more power, our 600W DC-DC
converter (October-November 1996;
siliconchip.com.au/Series/152) could
be used. Adjust its output voltage to
±55V by winding fewer turns on the
transformer. This could power a stereo amplifier for 500W (250W per
channel).
We looked for suitable commercially-made DC-DC converters but
couldn’t find any.
Electronic control of
induction motor speed
I have built a device to give closedloop torque control of a 3-phase induction motor using your 1.5kW VSD
(April & May 2012; siliconchip.com.
au/Series/25) which I built from an Altronics kit (Cat K6032). It works well
with manual torque control and PID
control; however, I noticed that the
motor speed would sometimes have
some annoying chatter.
Australia’s electronics magazine
When driving the inverter and motor in open-loop mode with a steady
voltage that I vary up or down, I discovered the motor speed steps neatly
in 60RPM increments and chatters
when the control voltage approaches
inverter speed step thresholds. So basically, the inverter produces frequencies in 1Hz steps.
The inverter internal speed set pot
(VR1) also varies the inverter output
in 1Hz steps. But when set to ramp up
to a set speed via the inverter internal
control, the motor spins up to the selected speed very smoothly!
The specifications for the inverter
state that its “speed control range” is
0.5-50 or 75Hz in 0.05Hz steps. It looks
like the inverter is stepping in 0.05Hz
steps when ramping between the discrete 1Hz settings, which isn’t what I
was expecting.
Can the inverter microcontroller be
set up so its speed setting increments
in 0.05Hz steps just like it does while
ramping? (N. R., Glenroy, Vic)
• Andrew Levido responds: the
1.5kW inverter was not designed to be
controlled in this manner. While the
frequency resolution is 0.05Hz, the
ramp up or down between frequency
setpoints will not commence unless
the setpoint has moved 0.5Hz from
the operating frequency.
This is to avoid the ‘hunting’ that
would otherwise occur if there was
the slightest bit of noise on the analog
input. I can see why this might look
like 1Hz steps when trying to move in
small frequency increments.
The threshold is set in the software.
This could be reduced to a threshold
of 0.05Hz if the code was recompiled.
This should work, but I have not tried
it. Note that we have not released
the source code because you need to
know what you are doing to make any
changes.
SL32 NTC
thermistor failure
I’ve had the Induction Motor
Speed Controller (April-May 2012;
siliconchip.com.au/Series/25) operational for about a year now, but the
SL32 10015 inrush current limiting
thermistor has now failed.
I noticed about six months ago that
it had a crack in it, but I left it in place
because the controller was working
OK otherwise.
It has obviously become very hot to
December 2020 109
the point where it became an opencircuit crumbling mess. Have you had
others report this problem?
I’ve modified my charred PCB and
mounted a new SL32 10015 offboard,
in the airflow at the top of the box.
Another modification I installed right
from the start of the initial build is a
full 12V supply to the muffin fan for
maximum airflow.
The new SL32 is running very hot
like the original, even in its new, improved location. I expect it also will
eventually fail.
How would it be if I installed two
MS32 5R020’s in series? That would
still give 10W but spread the load (heat)
between them.
• We have heard of numerous failures
of the SL32 devices in soft starters, but
not in the IMSC. We’ve also heard reports of (expensive) commercial and
industrial devices which use NTC
thermistors for inrush current limiting
failing during normal use, sometimes
explosively.
It seems that these parts can’t really
handle the rapid thermal cycling, even
though they are designed for this very
job. We aren’t sure if it is a quality
control problem at the factory, or perhaps that in some cases they are being
pushed harder than intended (despite
the device data sheet not giving any
guidance on this matter).
The SL32 10015 is rated at 15A
continuous, so you would expect it
to survive being part of a 10A motor
controller. Your solution of the two
MS32 5R020s in series should be a lot
more robust.
We suggest anyone building one of
our SoftStarter projects for use with
a large, bench-mounted power tool
should do what you have done and
use a larger number of lower-resistance NTC thermistors in series. Especially if it is going to experience frequent cycling.
Using Soft Starter
with large aircon
Can I use your July 2012 Soft Starter
for Power Tools (siliconchip.com.au/
Article/601) with a Panasonic 5kW
split system air conditioner?
It is no longer under warranty and
therefore the sky’s the limit, so I am
doing my research to convert it to run
off-grid permanently from a dedicated inverter and bank of batteries/solar panels.
110
Silicon Chip
I need to limit the inrush current
the compressor draws, as to prevent
the inverter going into trip mode under start-up conditions. It is rated to
draw up to 5.5A continuously in cooling mode and 6.8A in heating mode,
with peak currents of 14A and 17.5A
respectively. During normal operation,
the current I have measured is less than
5A. (B. A., Dee Why, NSW)
• It might work, but we wouldn’t recommend it, at least not without a lot
of testing first.
It’s going to be hard on the thermistors since a compressor starts up under quite a lot of load, especially if it’s
already hot. So they might fail pretty
quickly (as described above, albeit in
a different application).
We suggest that if you do try it, use
a larger bank of thermistors in series/
parallel or higher-rated thermistor(s).
That would necessitate a larger box at
the very least.
We’re also concerned about possible compressor burnout if it doesn’t
start properly, although the Soft Starter
does bypass the thermistors with a relay after a short time, so the compressor should start eventually, even if it
hard-starts. Still, we would want to
monitor its operation very carefully
for a while after installation.
It’s also possible that the relay could
have a short life if the compressor isn’t
starting until the relay kicks in, or if
the compressor is still drawing significant current by that time even if
it has started.
Varying Tempmaster
Mk2 range
I have just purchased a kit for your
Tempmaster Electronic Thermostat
Mk2 (February 2009; siliconchip.com.
au/Article/1337) from Jaycar Electronics (Cat KC5476). I am hoping to use
it to operate a cooling fan.
When I opened the instructions, I
found it has a range of 2-19°C, to suit
fridges. I would like to change the
operating range to about 15-35°C, although it would be good enough if I
could just increase the upper limit to
anything above 30°C. Is it possible to
change any components to achieve
this? Any help would be appreciated.
(T. J., Adelaide, SA)
• You can change the Tempmaster
Mk.2 temperature range to 14-35°C by
changing the 2.7kW and 3.3kW resistors in series with VR1 to 2.0kW and
Australia’s electronics magazine
2.7kW respectively. Or you can get an
even wider range of -5 to +40°C by using 1.2kW and 1.5kW value resistors.
Coil for the High
Energy Ignition System
I have been searching the internet
for weeks trying to find an appropriate high-energy ignition coil to use
with your High-energy Ignition design (May 1988; siliconchip.com.
au/Article/7739; built from a Jaycar
KC5030 kit). I would appreciate it if
you could recommend a high output
ignition coil or coils to suit.
I have been using the Prestolite points
distributor in my 1962 Studebaker
Hawk GT to run the ignition system for
many years without a problem. I have
owned the Stude since I was 21 years
of age – 50 years ago! (R. B., via email)
• We recommend you use a quality
standard coil such as the NGK coil
listed at siliconchip.com.au/link/ab5q
The High-energy Ignition system is
designed to work with a standard coil.
So-called high-energy coils can cause
arcing and misfiring if the distributor and ignition leads are not suited
to the higher voltage and faster voltage rise time.
Solar charger
for 32V battery
Several months ago, I purchased an
MPPT solar controller via eBay. I am
using three 20V solar panels to charge
a 16-cell (32V) lead-acid storage battery. The unit has a range of desirable features including reverse current
protection and continuous read-out
of the panel and battery voltage, current, amp-hours delivered and battery
state of charge.
However, it does not seem to be a
‘smart’ battery charger, despite having
an elaborate programming procedure.
As a result, I conclude that the controller should not be left connected permanently between the panels and the
battery, as the voltage can readily exceed 2.5V/cell (40V) in sunny weather.
At that voltage, the charging current
is around 3A.
My method of manual regulation is
to switch off the solar panels using a
DC circuit breaker when the battery
voltage reaches 40V. The battery remains connected to the MPPT controller. I recently noticed that there is a
continued on page 112
siliconchip.com.au
4mA current flowing back from the battery to the controller. Is that normal?
Have you ever published an MPPT
solar charger that would suit a 32V
200Ah battery being charged from
three standard 20V solar panels? (R.
W., Loxton, SA)
• The amount of current drawn by a
charger from the battery depends upon
the circuit design. It is normal for there
to be some current drawn by the controller (whether it is an MPPT charger
or not). After all, the charge controller
circuit needs power to operate, and
that can only come from the battery
when there is no solar power available.
The 4mA drain is not huge compared to the overall battery capacity
– it would take nearly 290 days to fully discharge your battery at that rate.
However, the less the charger draws
from the battery, the better.
Unfortunately, we have not published an MPPT solar charger to suit a
32V lead-acid battery. That is a somewhat unusual voltage; 12V, 24V, 36V
and 48V are more common. It’s close
enough to 36V that a charger designed
for a 36V lead-acid battery might work;
as long as it’s adjusted.
Modifying the 40A DC
Motor Speed Controller
I have a customer who is using a
number of your March-April 2008
40A DC Motor Speed Controllers
(siliconchip.com.au/Series/48) to
vary the speed of trolling motors on
their boat.
They want to speed up the soft-start
ramp or remove it. Currently, the soft
start runs for about 10 seconds, but
they need it to be under three seconds.
I’ve had a brief look at the assembly code for it, but my knowledge of
assembly is so rusty it would take
months to dissect it.
I did have a go at assembling the
source code which is available for
download from your website, but I got
several errors regarding missing functions named float_ascii2 and float_ascii4. They don’t appear to be part of
the standard library.
I also found that I had to add these
two lines at the top of the main .asm
file, which got rid of several other errors:
#define P16_MAP1 0
#define P16_MAP2 1
I know that you have since released
a more modern speed controller which
has the soft-start control they’re after,
but they’ve already built these kits and
have been using them for a little while.
We didn’t make a kit of the updated
one so it would still be a fair amount
of running around for them to switch.
(Tom Skevington, Kits Manager, Altronic Distributors)
• The float_ascii2 and float_ascii4
functions were in another file which
was not included in the ZIP download
for that project. That has now been
corrected. Thanks for the tip about the
two added defines which are needed.
The software has two variables in
which values are stored to increase or
decrease the PWM duty cycle, named
pdeltah and pdeltal. These are loaded
with +1 on lines 819-821 of the main
ASM file to decrease the speed, or -1
on lines 824-827 to increase the speed.
Since this gives a soft start time of
around 10 seconds, changing the increments to +4 and -4 should give a
ramp time of around 2.5 seconds. To
achieve this, change line 819 to:
movlw
0x04
movlw
0xFC
and change line 824 to:
This will also make the motor speed
ramp more quickly in response to the
rotation of the speed control pot, or
changes in load (ie, feedback).
SC
Advertising Index
Altronics...............................81-84
Ampec Technologies............. OBC
Dave Thompson...................... 111
Digi-Key Electronics.................... 3
Emona Instruments................. IBC
Jaycar............................ IFC,53-60
Keith Rippon Kit Assembly...... 111
LD Electronics......................... 111
LEDsales................................. 111
Microchip Technology.................. 5
Ocean Controls......................... 11
Premier Batteries........................ 8
RayMing PCB & Assembly........ 10
Rohde & Schwarz........................ 7
SC Vintage Radio DVD.............. 34
Silicon Chip Christmas Kits...... 52
Silicon Chip Online Shop....98-99
Silicon Chip PDFs on USB....... 25
Silicon Chip Subscriptions....... 35
The Loudspeaker Kit.com........... 9
Tronixlabs................................ 111
Vintage Radio Repairs............ 111
Wagner Electronics................... 63
Notes & Errata
Digital Lighting Controller pt2, November 2020: on p101, the parts list correctly includes a 27W 1W resistor for the Micromite
master unit but incorrectly lists it as 25W 1W for the CP2102 Adaptor module (it should also be 27W 1W).
Tiny LED Christmas Ornaments, November 2020: the parts list incorrectly lists the Bauble PCB dimensions as 91 x 98mm
when they should instead be 52.5 x 45.5mm. Also, the Cane PCB is incorrectly listed as 84 x 44mm when it should be 84 x 60mm.
Two new 7-band Audio Equalisers, April 2020: in the first batch of stereo equaliser PCBs sold (code 01104202), the connection
between the 220pF capacitor and 51kW resistor in the lower right-hand corner of the board went to the top of the resistor instead
of the bottom (which was floating). This can be fixed by cutting the track between the two components and running a short wire
from the bottom of the resistor to the nearest pad of the capacitor. PCBs sold from November onwards do not have this problem.
The January 2021 issue is due on sale in newsagents by Thursday, December 31st. Expect postal delivery of
subscription copies in Australia between December 27th and January 15th.
112
Silicon Chip
Australia’s electronics magazine
siliconchip.com.au
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