Is it possible measure the value of a Capacitor?

[Leon Amory]

I have a working Capacitor, it's very old (22 years), can I measure the
value of it?
And how should I do that?
There is a POSITIVE and NEGATIVE pin on it.

[John R. Hepburn]

Leon Amory wrote in message <37161EB7...@gei-aachen.de>...

I will make the assumption that you do not have a capacitance meter.

It can be done if you have the following, a fairly accurate means of
measuring time, a power source that you can set to 10v d.c., a digital
multimeter and a 1 Mega ohm resistor. If so, then this is what you do. First
set the power supply to 10 volts then connect its negative lead to the
negative of the capacitor. Now connect the positive power supply lead to one
end of the resistor and the other end to the positive of the capacitor. Now
hook your meter across the 2 leads of the resistor. What you do now is short
out the two terminals on the capacitor. Your meter should be reading 10
volts, if it is then get your time source ready. Remove the short and start
counting time. Stop your time count when the multimeter reading drops down
to 3.7v. The number of seconds is capacitance in microfarads. To be a little
more accurate, add 10% to compensate for your meters resistance (20 seconds
= 22 uf ). This is a crude way of doing it but I am assuming that you are
desperate. Also note that this is on the assumption that the capacitor is
not defective. If the meter stops moving down before hitting 3.7v or if it
jumps right down to almost nothing as soon as you release the short, then
forget it.

An easier way of doing it would be to take it to a local repair shop and ask
them to measure it.......naw....no sport in that!

Good luck

John R. Hepburn
John's Electronics Services
jhep...@recorder.ca

[Robert Hancock]

Yes, you need a meter with a capacitance measurement function on it. Though
the value is likely on the capacitor somewhere, it could be color code.

--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from hanc...@nospamhome.com
Home Page: http://members.home.net/hancockr

Leon Amory <am...@gei-aachen.de> wrote in message
news:37161EB7...@gei-aachen.de...

[John R. Hepburn]

John R. Hepburn wrote in message <9JuR2.244$bT2...@198.235.216.4>...

>
>Leon Amory wrote in message <37161EB7...@gei-aachen.de>...

>>I have a working Capacitor, it's very old (22 years), can I measure the
>>value of it?
>>And how should I do that?
>>There is a POSITIVE and NEGATIVE pin on it.
>>
>

Just read your post preceding this one. What I have said does not apply due
to size and state of your capacitor.

[EPotter]

The best thing to use is a capacitance bridge, but this takes some
experience to use properly. Anyone seriously interested in capacitors
being bad or good will want to read the series of articles on checking
capacitors by Cyril Bateman in Electronics World, four articles last year
and one in the current issue. He makes the point that the capacitance is
not the parameter to be mainly concerned about in checking a capacitor.