Capacitor codes

May 26, 2012 6 Replies

I've got an axial lead polarized cap with the following markings:


1K
50V

Its about 0.1 in diam x 0.3 in long



Now, I've seen 1K as a picofarad value, which would make this a 1nF cap. But this thing is big compared to other caps of this rating. A .001uF 1KV ceramic is much smaller. And this doesn't make sense in the circuit its in.



In other contexts, the K letter code defines the tolerance. But that usually follows a three digit value code.



So, what is it that I'm looking at? The cap is bad, or I'd throw it on a meter and figure it out.


Paul Hovnanian mailto:Paul@Hovnanian.com ------------------------------------------------------------------ A mathematician is a machine for converting coffee into theorems.

But

n.

lly

As you say, Paul, the value could be various capacitances depending on what= coding was used. From the size, I would suspect that 1uF would not be unre= asonable, but that depends on the 'type' of cap it is [electrolytic or tant= alum or ?]. I don't suppose there is another similar cap on the board that = IS good that you could measure. Even if it's value is somewhat different, i= t would allow you to decode the markings.

Neil S.

As you say, Paul, the value could be various capacitances depending on what coding was used. From the size, I would suspect that 1uF would not be unreasonable, but that depends on the 'type' of cap it is [electrolytic or tantalum or ?]. I don't suppose there is another similar cap on the board that IS good that you could measure. Even if its value is somewhat different, it would allow you to decode the markings.

===========================

I was going to suggest it was a tantalum, but I checked a catalog, and both the capacitance and voltage are too high. And I've never seen an axial-lead tantalum.

"William Sommerwerck" wrote in news:jpr2b9$n09$ snipped-for-privacy@dont-email.me:

In the old days, axial leaded tantalums were the norm. Usually had a metal case.

Doug White

No hard to read point. I checked with good magnification.

K as a tolerance code agrees with some stuff I've found on line.

But here's the acid test: The circuit works with a 1uF cap. So this means 1K is either 1E3 nF or 1uF and the K is tolerance (10%). Either interpretation would suggest that electrolytics (or polarized caps) use a different base value than ceramics and others (which use 1 pF).

Aren't standards great? That's why we have so many.

Paul Hovnanian mailto:Paul@Hovnanian.com ------------------------------------------------------------------ Time is the best teacher; Unfortunately it kills all its students.

Might I ask whether it would be useful to determine what /type/ of capacitor this is? That would go a long way in deciding its value.

We (the accumulated wisdom of s.e.d and s.e.r) seem to think its an aluminum electrolytic. Long odds on a tantalum.

Paul Hovnanian mailto:Paul@Hovnanian.com ------------------------------------------------------------------ Dyslexics are teople poo!

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