From: Hans-Bernhard Broeker
Subject: Re: what is 100R mean in a schematics?
Date: 3 Jan 2003 12:02:36 GMT
Organization: Aachen University of Technology (RWTH)
References: <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org>
NNTP-Posting-Date: 3 Jan 2003 12:02:36 GMT
In comp.arch.embedded Chris Ainslie <email@example.com> wrote:
> told me where C3 and C4 should go and that C3 was a 22uF ceramic cap and C4
> was a 220uF ceramic cap.
> Now, one of them was a tiny yellow one with a shiny coating and had the
> number 224 on it. The other was one of those orange disc type ones with a
> matt finish and on it, it said 223Z.
In the light of earlier posts in this threads, the answer should be
pretty clear: 224 means 22*10^4 in some unit, and 223 means 22*10^3 in
(hopefully) the same. From context, the unit is nanofarads, i.e. 224
is 22*10^4 nF = 220 uF.
Of course, the simpler answer would be: in case of doubt *measure*
them. Sadly, most multimeters don't have an "official" way to measure
capacitance. But for capacitors this large, you may be able to trick
them and use the resistance measurement in "ballistic" mode. Use the
meter as if you wanted to measure the resistance of the capacitor.
Repeat the measurement, alternating the orientation of the part. Each
time, the gauge should start moving to the right, then return back to
the "infinite resistance" mark at the left end of the scale as the
current from the ohmmeter charges it. The point of return is the
measurement. The larger the capacitance, the further to the right
it'll be, as it takes longer and longer to charge it. The measurement
is not very precise, but a factor of ten should always be easy to
Real good analog multimeters even have a printed scale for this
Hans-Bernhard Broeker (firstname.lastname@example.org)
Even if all the snow were burnt, ashes would remain.