This is only a preview of the April 2021 issue of Silicon Chip. You can view 0 of the 112 pages in the full issue. For full access, purchase the issue for $10.00 or subscribe for access to the latest issues. Items relevant to "":
Articles in this series:
Items relevant to "Digital FX (Effects) Pedal - Part 1":
Items relevant to "Refined Full-Wave Motor Speed Controller":
Articles in this series:
Items relevant to "High-Current Four Battery/Cell Balancer - Part 2":
Items relevant to "Arduino-based MIDI Soundboard - Part 1":
Purchase a printed copy of this issue for $10.00. |
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. Send your email to silicon<at>siliconchip.com.au
Battery Balancer Mosfet
inverter/driver query
I would like to raise a potential
problem with the use of the N- &
P-channel Mosfets in the QS6M4
device as a complementary pair
in the design of the High-Current
Four Battery/Cell Balancer (March
& April 2021; siliconchip.com.au/
Series/358).
They are connected back-to-back
across the 3.3V supply, so the only
resistance in the circuit is the devices themselves. The N-channel
gate threshold is 0.5-1.5V, while the
P-channel is -0.7 to -2V. So potentially, from 0.5V to 2.6V (3.3V − 0.7V),
both transistors are on.
At -1.5V, the P-channel RDS(on) is
0.155W, and at 1.5V, the N-channel
RDS(on) is 0.17W. So, if you simplistically apply V = IR, you get I = 10.15A
= 3.3V ÷ (0.155W + 0.17W). The maximum pulsed drain current for both
devices is 6A.
You limited the surge current
through Q11a/b into Q10 with a 1W
resistor. I’m wondering if the complimentary pair should have similar
protection, even though the ‘both on’
time is short. Could it shorten the life
of the QS6M4 otherwise? (D. H., St.
Ives, NSW)
• Duraid responds: I spent considerable time validating the use of these
Mosfet pairs during the design phase.
Shoot-through currents in a CMOS
inverter are a concern, especially at
higher temperatures where the gatesource on-thresholds start creeping
down.
The 0.155W/0.17W resistance values
quoted are for devices that are well
and truly on. Resistances around the
1.65 (Vdd ÷ 2) point are nearly an order of magnitude higher, especially for
the PMOS section. Keep in mind that
the gate threshold voltages quoted are
typically for channel current flows of
around 1mA, not the many amps that
the devices are capable of with higher
gate-source voltages.
At these low gate voltages, it’s thersiliconchip.com.au
mal degradation that you need to be
careful to avoid. These parts claim to
be able to tolerate 1W, so long as thermal limits are observed. During the
design phase, I ran some simulations
which showed an order-of-magnitude
headroom to this limit, and significant
thermal headroom, even allowing for
the fact that these parts are quite near
the inductors/power FETs.
So to summarise, you do have to be
careful using Mosfet pairs as inverters like this, but we have verified that
these particular parts are suitable in
this configuration.
Sourcing LM5163 for
Battery Multi Logger
The LM5163DDAR buck converter (regulator) IC used in the Battery
Multi-Logger seems to be in short
supply. Digi-Key and Mouser are both
quoting a seven month lead time. Do
you know of an alternate supplier or
device? (R. M., Paynesville, Vic)
• You can use the automotive version, which is identical to the part we
specified, just a bit more expensive:
LM5163QDDARQ1 or LM5163HQDDARQ1. It is in stock at both Digi-Key
and Mouser.
Reed relays are
underrated for 1A PSU
I am reading my way through the
February 2021 issue of Silicon Chip. I
have a couple of comments about the
article on the Arduino-based Adjustable Power Supply, starting on page
38 (siliconchip.com.au/Series/357).
There is no back-EMF diode across
the coil of the reed relay. Surely one
is required to prevent damage to the
Arduino pin.
Also, both the Altronics and the Jaycar reed relays have a contact rating of
0.5A. So rating the power supply at 1A
and expecting the relay to make and
break that current is not a good idea.
My experience is that reed relays will
tend to stick closed if overloaded.
I note Jaycar do sell a reed relay with
Australia’s electronics magazine
1A rated contacts, Cat SY4036. Altronics don’t seem to have any 1A-rated
reed relays.
Finally, I am looking forward to
reading the article on the computer
upgrade. It is good to have this as I
am interested in learning of the potential ‘snags’ when doing so. (D. W.,
Hornsby, NSW)
• Regarding the relay coil, since the
Arduino pin is pulled to ground and effectively shorts the coil terminals when
switching it off, there is no opportunity
for a high-voltage spike as would occur
if the circuit were simply opened. The
circulating current decays via the driving pin, so it never goes above the coil
operating current. We have never seen
this sort of arrangement fail.
It’s when you have an open-collector
or open-drain relay coil driving arrangement that the back-EMF quenching diode is needed.
You are probably right about the
Jaycar/Altronics relays being slightly
underrated for this project. We have
used similar relays in the past rated
to break 1A, but as you point out, the
ones we specified are only rated to carry 1A. Fortunately, these relays have a
quite high (100V) voltage limit, and the
current limit can be set in the PSU to
provide an extra degree of protection.
Oddly, the Altronics Cat S4100 &
Cat S4101A relays have a rated switching current of 1A but are described as
“0.5A 5VDC SPST DIP PCB Mount
Reed Relay”. We aren’t sure if that is
a mistake, or if they can actually break
a higher current than they are rated to
carry continuously.
Panel meters fail when
used with inverters
After reading Jim Rowe’s review of
mains panel meters (December 2020;
siliconchip.com.au/Article/14678), I
bought a PZEM-051 panel meter to fit
to a portable power supply. This consists of two deep-cycle AGM batteries wired in series with provision to
connect up to three 24V DC to 230V
AC inverters. Two of the inverters are
April 2021 107
modified square wave types, while one
is a pure sinewave type.
The panel meter immediately failed.
After checking the wiring carefully,
I removed the back and checked for
signs of faulty components. Q1 (a 600V
Mosfet) looked stressed. Tiny globules
of solder were stuck to the Mosfet and
the adjacent PCB. When power was
again applied, the Mosfet became too
hot to touch within seconds.
I contacted the supplier, who eventually advised that the meter was not
designed for use with inverters, although there was no information about
this in the supplied instructions.
Is it possible to fit a transient voltage
suppressor across the 24V power supply to a new meter to prevent another
failure? The Jaycar Cat ZR1152 TVS
looks good. I might have to fit two in
series to prevent premature tripping,
though. Any suggestions you can provide will be much appreciated. (I. M.
P., Fullarton, SA)
• The waveform from an inverter, especially a modified square wave type,
has much greater harmonic content
than a normal mains waveform, so we
are not surprised that this could damage a low-cost panel meter.
Adding a TVS across the DC side of
the inverter probably won’t help, as
it is likely the spikes and steps in the
‘230V AC’ waveform that are causing
the damage. You would need to filter
that waveform before feeding it to the
panel meter(s).
However, finding a filter that will
remove enough harmonic content to
keep the panel meters safe, without
damaging the filter itself, might not
be easy. We suggest that you try using
this Jaycar EMI filter (Cat MS4001) between each inverter’s output and the
panel meters/outputs.
How much to build the
USB SuperCodec
Can you give me an approximate
costing for parts to build the USB
SuperCodec (August-October 2020;
siliconchip.com.au/Series/349)? (R.
P., Tea Gardens, NSW)
• Phil Prosser added up what he paid
for all the parts to build the prototype,
and came up with a figure of $439.28,
including the power supply and case,
but not including the PCB, for which
we charge $12.50 plus delivery costs.
Not bad, we think, considering the resulting performance.
108
Silicon Chip
High Power Ultrasonic
Cleaner not working
I have built the High Power Ultrasonic Cleaner (September & October
2020; siliconchip.com.au/Series/350),
but I am having trouble getting it to
work correctly. After setting it up, I
switched on the unit and checked the
5V volt supply at IC1 and IC2. I got a
reading of 5.04V.
I then filled the bath with 3.5L of water, switched it on and tried to calibrate
it. The 25% and 50% LEDs gave a brief
flash, then the run LED lit up, but the
unit would only run at 10% power. I
checked the connections to the transducer; they all appear OK. I initiated
the diagnostic mode and could only
get a maximum reading of 2V at TP1.
I rewound the transformer, adding
an extra layer of 28 turns. This time,
when calibrating, the 25% LED stays
on, and the 50% LED pulses every
two seconds. After approximately two
minutes, the run LED lights up, but it
will only operate at 25% power.
In diagnostic mode, I now get a maximum reading of 4.8V, at which time
the unit goes into current overload.
I tried altering the quantity of water
in the bath, to no effect. I removed ten
turns/windings from the transformer.
This dropped the maximum voltage
reading on TP1 to 3.7V, but made no
change to the calibration or running
of the unit. Do you have any ideas? (P.
H., Mosgiel, New Zealand)
• It sounds like the transducer resonance point is not being found. Try
running the diagnostics and sweeping
the frequencies manually to find the
maximum current by measuring the
voltage at TP1. If this voltage goes over
the 4.8V maximum, reduce the number
of secondary turns on the transformer.
The number of turns needs to
be such that the current limit isn’t
reached at resonance. This is the only
way to find the transducer resonance
frequency correctly.
Then the cleaner should then run
correctly, and you can achieve the ultimate power by altering the transformer
secondary windings, which should be
within a few turns of the ideal number once you are reaching resonance
without overloading it.
Tapped transformers
with 45V Bench Supply
I have just ordered the parts and PCB
Australia’s electronics magazine
to build your 45V 8A Linear Bench
Supply (October-December 2019;
siliconchip.com.au/Series/339). The
circuit design looks good to me, but
I’d like to make a few modifications
to reduce heat dissipation for my use.
I built a number of the older ETI-163
supplies many years ago. That design
used multiple winding on the transformer, switching them in series as the
rotary potentiometer was rotated on
the front panel. Is there a reason why
you didn’t use a similar approach for
your supply?
I designed my own version using
three separate 14V 10A transformers
switched to series or parallel combinations. I chose 14V as those combinations are a few volts above the most
commonly used voltages for my industry, 13.8V and 28.8V.
I used a simple op-amp voltage divider to switch the windings based
on the ‘selected’ voltage on the
front-mounted voltage pot. My voltage/current regulation was based on
the old ETI-163 power supply.
At 13.8V DC output, the transistors
were only dropping 5.9V, so at higher
currents, the heat dissipated was minimal (60W at 10A or 120W at 20A).
This also has the advantage of lowering
the output impedance of the ‘source’
as there are two windings in parallel
(great for high current loads).
At 28.8V DC output, two of the transformers are connected in series, with
one unused. Past 32V, all three windings are in series, giving up to 60V <at>
10A before the series pass transistors.
Using eight MJE15003 transistors on
two large heatsinks with 2 x 80mm
fans, the heat was spread out quite
well, and I have never encountered
any overheating problems.
However, at 16V DC, the heat output is quite significant at 235W with
a load drawing 10A.
I also had a 0.5A/10A range select
switch, which switches a different
shunt in the negative line to allow fine
current limit control at lower currents.
Metering was analog like the ETI-163
as they are fast and easy to read at-aglance, especially the current meter.
I’ll probably add this feature to the
new supply, maybe with three current
ranges: 0-500mA, 0-1A and 0-10A. (B.
N., Marine Terrace, WA)
• We did consider using a multi-tap/
series/parallel transformer configuration while designing the 45V PSU,
but we couldn’t find any suitable offsiliconchip.com.au
the-shelf transformers at reasonable
prices. We didn’t want to use multiple
transformers as that would result in a
much bigger, heavier unit.
The switchable shunt idea is interesting, although you’d have to have
your wits about you to know what
range you were using at any given time.
Also, the switch resistance could introduce some inaccuracies, and possibly
unreliability long-term.
have not tested it with Python 3.
The error “ImportError: No module
named ‘urllib2’” confirms this, as per
the following StackOverflow question:
siliconchip.com.au/link/ab76
If you want to push ahead and try
to make it work with Python 3, the advice on that web page is a good start.
Tide Chart Python
version mismatch
A colleague (who does not read your
magazine; shame on him!) has an appliance where the backlight has failed
on the LCD panel.
Am I correct in assuming that the
light is integral to the panel, and hence
cannot be replaced? I suppose that
by squinting at the panel, or perhaps
by shining a bright light upon it, the
segments could be discerned. (D. H.,
North Gosford, NSW)
• It depends on the LCD panel. You
I am trying to get the code for your
Raspberry Pi Tide Chart (July 2018;
siliconchip.com.au/Article/11142)
running, but I am getting an error
“ImportError: No module named
‘urllib2’”. (P. C., Balgal Beach, Qld)
• We suspect that you are trying to
make the Tide Chart work with Python
3. It was written for Python 2, and we
How to fix failed
LCD backlight
can experiment by applying light to
the panel using a small torch. There
might be a way to provide backlighting by feeding light in from the panel’s side or back.
Front-lit LCD panels are harder to
control for lighting, but you may get
sufficient display brightness with front
lighting. The display contrast is usually poor with front lighting.
We occasionally publish entries in
Serviceman’s Log where contributors
have successfully replaced the backlighting on various LCD screens. You
really have to open it up to see whether it is possible for that particular display (unless you can find information
about that aspect of it online).
Ferrite bead selection
for amplifier
The Ultra-LD Mk.4 200W RMS
Power Amplifier (August-October
How is negative feedback affected by phase shift?
When feedback is being discussed,
the effect of phase shift on a feedback loop is usually considered, but
always in the most extreme situation
where the phase shift is large enough
to set up positive feedback and drive
the circuit into oscillation.
But surely, any phase shift should
have a detrimental effect on feedback since phase shift is caused by
a time delay in the feedback circuit.
That in turn means that the circuit is
feeding back an error to a different
part of the signal; in effect, trying
to correct an error that has already
happened and the source signal has
moved on.
And yet, the vanishingly low distortions being measured in some
high-end amplifier circuits, like
those published in Silicon Chip,
suggest that this is not happening.
Can someone explain why feeding
back a delayed signal is not a problem for a feedback circuit? (P. T.,
Casula, NSW)
• Yes, phase shift has a detrimental
effect on negative feedback used for
distortion reduction or accurate gain
setting. It’s worse at higher frequencies as the circuit will typically have
a fixed feedback delay, representing
a larger phase shift relative to higher frequency signals. This is largely
siliconchip.com.au
why audio amplifiers usually have
rising distortion with frequency, typically evident above 1kHz.
Therefore, audio amplifiers usually are designed to operate just on the
edge of stability, with the minimum
possible delay, pushing this point
of rising distortion above 20kHz
where it is not audible (and the amplifier will generally be designed
not to reproduce signals above this
frequency).
Consider that the open-loop bandwidth of an audio amplifier will typically be in the megahertz, yet it is
only tasked at reproducing frequencies (in closed-loop mode) up to
20kHz. So if the phase shift is, say,
90° at 2MHz, that equates to a feedback delay of 125ns (90° ÷ 2MHz ÷
360°). For a 20kHz signal, that’s a
phase shift of 0.9° (360° × 125ns ×
20kHz).
Therefore, the negative feedback
is still more than 99% effective, reducing the open-loop distortion by
more than 40dB. As long as the design is fairly linear (ie, open-loop
distortion is not gross), this is usually enough to give a very low distortion figure even at 20kHz.
If you look at the evolution of our
amplifiers, 20 years ago, we were
achieving figures of <0.001% <at>
Australia’s electronics magazine
1kHz, but significantly higher (say,
between 0.01% and 0.1%) at 20kHz.
These days, the open-loop bandwidth has been raised, making feedback more effective; open-loop linearity is better, and other factors
have been improved to the point that
we are achieving close to 0.0001%
<at> 1kHz and still well under 0.001%
<at> 20kHz, leaving little room for further improvement.
So you are right, the phase shift in
a negative feedback circuit is undesirable, but luckily, it can be kept to a
low level where it is not bothersome.
In circuits like low-pass and highpass filters that inherently have a
phase shift within the audio frequency band, the linearity of the change
in phase with frequency is usually
excellent. We make sure that it is by
using all linear components in the
RC networks, and so it does not introduce harmonic distortion.
It does introduce a frequencydependent phase shift, but in theory, for normal ‘listening’ conditions, this is inaudible. It can cause
problems in certain scenarios like
interactions between drivers in
multi-drive loudspeaker systems,
in which case, the crossover circuit
design can be critical in achieving
good results.
April 2021 109
2015; siliconchip.com.au/Series/289)
uses an SMD ferrite bead. What value of inductance/resistance should it
have? There are many to choose from
at Digi-Key. (I. G., Oak Flats, NSW)
• The ferrite bead type is not critical.
Ferrite beads don’t have any significant inductance or resistance. They
are usually specified with an impedance in ohms at 100MHz.
The cheapest from Digi-Key in the
M3216/1206 package are rated at either 600W or 1kW at 100MHz, and either would be fine. For example, the
Bourns MH3261-601Y or Eaton MFBM1V3216-102-R.
Component damage in
CLASSiC DAC?
I have finished building your CLASSiC DAC from the February-May 2013
issues (siliconchip.com.au/Series/63).
I went through the testing procedure,
and everything was fine in regards to
the power supply until I bridged LK1
and LK2.
The DAC chip heated up rapidly, so
I inspected the board and found I had
accidentally fitted TOSLINK transmitters and not receivers.
I have since replaced them with the
correct receivers and carried out the
setup procedure again. But I still have
the same problem with the CS4398
DAC chip rapidly heating.
Upon further investigation, I found
that when the JP1 link is set for 3.3V,
the unit will continuously scan the
four sampling rate LEDs and not detect
any channels, and there is no audio
output. The DAC chip does not get hot.
When JP1 is connected to 5V, the
unit does select channels and detects
the sampling rate, but that is when the
DAC chip gets very hot in a matter of
seconds. There is audio output, but it
is very noisy.
I have also tried with JP1 out and the
unit powers on fine, selects all channels and audio from USB and SD card
can be played back, but there is a lot
of noise through both the headphone
and line outputs. However, the noise
is not as bad as when 5V is selected.
Could it be that having the wrong
TOSLINK transmitters/receiver fitted
has damaged the CS8416 receiver chip
and introducing the noise to rest of
the circuit? I would love to hear your
thoughts before I purchase a new chip.
(J. R., Warrane, Tas)
• We can’t see an obvious way that fit110
Silicon Chip
ting TOSLINK transmitters instead of
receivers would damage anything. We
wonder if you have another problem
and the TOSLINK transmitter error is
just a coincidence. Do make sure that
the TOSLINK receivers you have fitted
are the right type, though.
The only thing that jumper JP1 controls is the voltage fed to Q13b, which
then goes to the TOSLINK receivers
and nowhere else. Their outputs are
AC-coupled to the CS8416, so it should
not be possible for the wrong voltage
to be fed back. We suspect you have a
short circuit from some point on this
rail to something that feeds to the DAC,
such as the +3.3V rail.
This short could be between the pins
of JP1, or perhaps between some pins
of Q13. It could be elsewhere, but we
can’t see any other obvious locations.
We suggest removing the jumper
from JP1 and check for continuity between the middle pin and both of the
outer pins. If you find continuity then
something is wrong. Do the same for
the pins of Q13, keeping in mind that
pins 5 & 6 and pins 7 & 8 are intentionally connected together.
If that still doesn’t help, check the
board carefully for short circuits, especially between IC pins.
Modifying the IMSC to
run from 115V AC
I purchased a couple of kits for your
Induction Motor Speed Controller
(April & May 2012; siliconchip.com.
au/Series/25) way back when, and am
now getting around to building them.
With only a couple of minor mistakes,
it has gone well.
I was reading through your articles
describing the design and function,
and I have a couple of questions/requests. Most of this has to do with
the fact that I live in the USA, and our
mains power is 120V AC (240V AC for
large appliances).
I don’t want to have to use 240V AC
for all my motor applications. What is
the low-voltage cutoff? Is this a software feature that could be modified?
I’d like to have the speed settings
ratio be based on what we have for
power here. That means a 60Hz default ramp up and a 90Hz top speed.
I think that could also be changed in
the software quite easily.
Would you be willing to share the
source code? I imagine I’m not the only
one that would like to make a couple
Australia’s electronics magazine
of tweaks. GitHub and a public license
to protect you and/or keep people from
profiting from your work. (A. D., Columbia Heights, Minnesota USA)
• You would need to change transformers T1 and T2 to run the IMSC
from 110-120V AC as they would not
produce a high enough output voltage
otherwise.
A possible alternative to changing
these transformers would be to use the
specified transformers, but change how
they are wired to the diode bridges. T1’s
configuration would need to change
from a bridge rectifier to a full-wave
voltage doubler, and T2 would need
to be rewired to have its secondaries
in series rather than in parallel.
The under-voltage lock-out can’t be
changed in software. If you modify T1/
T2 to produce the correct +15V HOT
and 7V rail voltages with a ~115V AC
input as described above, the circuit
should operate normally. You couldn’t
connect it to a 220-240V AC source after those modifications, though.
The 0.5-75Hz range was chosen to
include 60Hz as an option. The latest software gives a way to increase
the maximum speed to 100Hz, which
should be more than enough.
We haven’t made the source code
to this project freely available upon
the designer’s request, because modifying it could be very dangerous. The
IMSC is not something that inexperienced people should fiddle with, and
we believe that giving away the source
code would encourage that.
Dual Power Supply
wanted
Has Silicon Chip ever designed a
simple variable dual power supply?
(R. M., Melville, WA)
• Yes, we have published a few; the
latest was the Dual Tracking Supply
(June & July 2010; siliconchip.com.au/
Series/8). We have PCBs available for
that project, and there is an Altronics
kit (Cat K3218). If building that, please
check our Notes & Errata page as there
were some errata published for it.
Other similar supplies published
include:
• Easy-to-Build Bench Power Supply (April 2002; siliconchip.com.au/
Article/4083)
• Beginner’s Dual Rail Variable Power Supply (October 1994; siliconchip.
com.au/Article/5220)
continued on page 112
siliconchip.com.au
• Dual Tracking ±50V Power Supply (April 1990; siliconchip.com.au/
Article/7258)
• Dual Tracking ±18.5V Power Supply (January 1988; siliconchip.com.au/
Article/7828)
the Jaycar Cat SY4080 (3A rated) and
SY4084 (40A rated). These would
need to be wired up and housed in an
Earthed metal enclosure and wired according to the Australian wiring standards for mains equipment.
Reducing switch wear
from arcing
Direct Injection Box
query
I have a computer (Apple Mac), a
printer (Brother) and several other
small items plugged into a powerboard
fitted with a switch.
After I have finished using the computer, I shut it down, wait until all
the screen displays have switched
off, then turn all the power off via the
switch on the powerboard.
Occasionally, there is a ‘blat’ sound
that comes from the switch. I assume
that this is a spark. I have had to replace the switch several times over
the years, as the contact points in the
switch have become stuck or welded
together. Is there any way to reduce
or eliminate this sparking? (G. H., via
email)
• One method to reduce switch contact wear due to arcing is to place an
X2-rated 10nF 250V AC capacitor
across the switch contacts (eg, Jaycar
Cat RG5230).
This will reduce the transient voltage across the switch contacts as they
open. Adding the capacitor leaves a
residual current flow that bypasses the
open switch (around 8mA).
Higher value capacitors can be used,
and might suppress the sparking more
effectively, but with a higher residual current.
Another method is to switch the
mains supply using an electronic switch such as a Triac. There are
electronic relays that do this, such as
Some years back, you presented an
active direct injection box for guitars
to plug into a PA system. The design
included a low-cost transformer from
Altronics or Jaycar and a JFET front
end powered via the audio mixer
phantom power supply.
We built several of these for our local church and need to make more.
While you can buy a commercial unit
for around $100, I recall that these DI
boxes were very cost-effective; certainly a lot less than $100.
I can’t remember whether it was
EA or Silicon Chip magazine. The DI
boxes we constructed have proven to
be very robust and deliver excellent
sound quality. Can you advise when
that project was published? (N. A.,
Canberra, ACT)
• The DI Box design you are after
is probably the one from Electronics Australia, February 1998 (97di12:
“Direct Injection [active] Preamp using a JFET” ). You can order a scan of
that article via www.siliconchip.com.
au/Shop/15
Alternatively, Silicon Chip has published passive and active DI Boxes.
Our passive version (October 2014;
siliconchip.com.au/Article/8034)
uses a high-quality transformer from
Altronics, while the Active DI Box
(August 2001; siliconchip.com.au/
Article/4158) does not use a transformer.
SC
Advertising Index
Altronics...............................83-86
Ampec Technologies................. 49
Analog Devices........................... 7
Control Devices Australia............ 9
Dave Thompson...................... 111
Digi-Key Electronics.................... 3
Emona Instruments................. IBC
Hare & Forbes............................. 5
Jaycar............................ IFC,53-60
Keith Rippon Kit Assembly...... 111
LD Electronics......................... 111
LEDsales................................. 111
Microchip Technology...... 13, OBC
Ocean Controls........................... 6
SC Colour Maximite 2............... 75
Silicon Chip Binders............... 111
Silicon Chip Shop.............. 87, 98
Silicon Chip SiDRADIO............ 19
Switchmode Power Supplies..... 12
The Loudspeaker Kit.com......... 10
Tronixlabs................................ 111
Vintage Radio Repairs............ 111
Wagner Electronics................... 47
Weller Soldering Iron................. 11
Notes & Errata
High-Current Battery Balancer, March 2021: in the parts list on p27, several Mosfets (Q11,Q12…) are listed as “S6M4” types.
The correct type code is QS6M4.
Arduino-based Adjustable Power Supply, February 2021: while the specified SY4030 relay from Jaycar is rated to carry 1A,
it only has a 500mA switch rating. The similar S4100 relay from Altronics specifies a 1A switching current. Power supplies built
using the Jaycar part should set the current limit no higher than 500mA to avoid damage to the relay. Other similar relays are
available with a 1A contact rating; it appears that this refers to the carry current only, and not the switching current, so check
the data sheet if substituting a different part.
LED Party Strobe Mk2, August 2015: the link at lower-left should be positioned as shown in the photo on p87, not the overlay
diagram (Fig.2) on p86, which incorrectly has it shown in the “MAX” position.
The May 2021 issue is due on sale in newsagents by Thursday, April 29th. Expect postal delivery of subscription
copies in Australia between April 27th and May 12th.
112
Silicon Chip
Australia’s electronics magazine
siliconchip.com.au
|