|Written by Martin
Pickering of 'Television Magazine' in the UK
Check out his web site at
This is no ordinary
meter: It has been designed to check the ESR of
electrolytic capacitors in circuit Ė a basic
test of the goodness of these notorious
components. It can also do other things, as
Martin Pickering of the UK explains.
Buy the Capacitor Wizard
A week or two ago one of my trade customers phoned me
for help with a BT SVS250 satellite receiver. " I
replaced all the parts included in RELKIT 17" he said,
"but it still doesnít give any on-screen decoder
I suggested that he used his wifeís hairdryer on the
main PCB, since the electrolytic capacitors in the video
section are notorious as a cause of this symptoms, also
An hour later he phoned back. "Your hairdryer idea
didnít get me anywhere" he said, "waste of time. But I
found the fault right away when I used my Capacitor
"It was C232, and I found it with my Wizard."
"Ummm, sorry. Whatís this Wizard thing?"
"Itís advertised in Television. Bought one.
Wonderful. You should buy one."
Now I confess that although I write the occasional
piece for the mag I donít often read the adverts. So
this recommendation came as something of a surprise.
Then thereís the fact that your reviewer doesnít usually
buy things. I mean, I wouldnít be right somehow to
actually pay for something to review, would it?!
Anyway I sent an e-mail to SEME and ordered one. It
arrived next day, and I posted my cheque by return.
My first impressions were that the meter was "chunkyí
and maybe on the expensive side. Itís housed in what is
obviously a proprietary molded black box, with brown
feet glued to the underside. The meter movement seemed
to have been fitted as an afterthought: it stands a
centimeter proud if the box. The unit is large in
comparison with a modern multi-meter. This was not going
to fit in my pocket.
But first impressions can be misleading. This is an
instrument that has been designed for a specific
purpose, and part of that purpose is to sit in a
workbench without wandering about with every draught
from the window. The chunky box makes sure of that, and
the brown feet are functionally perfect!
The face of the meter is colorful and easy to read.
The unitís controls are simple: an on/off switch and two
recessed preset adjusters that, so far, Iíve not had
need to touch. The bright, yellow-painted cover might be
chunky, but itís the sort of Morris 1000 type chunkiness
you learn to love. And the probes Ė I just love to hold
Not a Capacitance Meter
"But," I hear you say, "I already have a capacitance
Well this isnít a capacitance meter. What it measures
is the effective series resistance (ESR) of electrolytic
capacitors, and it does so with the capacitor in circuit
You will, of course, remember Ray Porterís excellent
articles on the subject of ESR back in the January and
April 1993 issues of Television. To recap, with an
electrolytic capacitorís the ESR is a much better guide
to the capacitorís state of health than its actual
value. In a chopper power supply, to take one
application, the electrolytics take a continual
hammering from fast rise-time, high-current pulses.
These can degrade a capacitor in such a way that is no
longer able to smooth the pulses. Its capacitance value
might still be all right, but its effective series
resistance may be far too high. This is what the
Capacitor Wizard measure.
How, I wonder, could I have managed without this
instrument for so long? For years Iíve treated
electrolytic capacitors with suspicion. I have replaced
without testing them any were discolored or oozing, and
have continually been surprised when the culprit turned
out to be other than the one(s)I suspected. Then been
even more surprised to find out that its capacitance
value was almost correct.
Now, with the Wizard, I simply ensure that the big
electrolytics are discharged, then prod each one with
those wonderfully long-pointed probes. If the Wizard
bleeps, the capacitor is OK: no need even to look at the
meter. If it does not bleep, I look at the meter and
make a judgment. If the meterís needle comes to rest in
the Ďcompareí region, I do the test again with a new
capacitor of the same value in order to provide a
comparison. If the needle comes to rest in the Ďbadí
region, the capacitor goes in the bin and a replacement
This works fine with electrolytics of value down to
10 microfarad. With practice, you can make a considered
judgment down to 1 microfarad. Above 100 microfarad, the
meter always bleeps unless the capacitor is bad.
How it Works
The Capacitor Wizard generates a 100kHz sine wave
test signal of only 5mV RMS. This is insufficient to
switch on any semiconductor device present, so the meter
is not affected by other components in the circuit. As
it measures reactance, it will happily ignore even a
100ohm resistor across the capacitor being tested. In
fact the only times when itís fooled are when the
capacitor under test is short-circuit Ė check with an
ordinary meter if in doubt Ė or thereís a good capacitor
in parallel with a bad one. You soon get to spot these.
The Capacitor Wizard was designed by an American
engineer who actually uses it himself. It shows! The
instruction booklet is clear and concise, and even
includes tables to enable you to check capacitors with
values as low as 0.1 microfarad and small value
inductors as well. Thereís also an explanation of how to
check for leaky or short-circuit semiconductor devices.
This meter is more versatile than you might think!
The total price of the Capacitor Wizard is $179.95
U.S. plus shipping and can be obtained from many
distributors around the world or you can order directly
from our online catalog. In the U.S. and Canada call
1-800-394-1984 or International call 316-321-2800 or fax
An absolute must for every
Technicians Bench and Field Kit
Capacitor Wizard Manual
Regular Price $229.95
Capacitor Wizard Special Price
Capacitor Wizard with a
CapWizSavr installed for
for your bench and One for the field. This is an
absolute indispensable piece of test equipment
for the technician.