Cap measurement ??

[guitarhobbyist]

Hey all thought someone here might shed some light on this. I am measureing an unkown cap that I have because I need a replacement. It reads on it "220, 5%, 500V, SM". On the meter (Fluke) it measures 00.36nF. What am I looking for in the replacement? thanks in advance.

 

[jackthehack]

What is that going in, an amp?

 

[-CB-]

Depends on the idle setting of your fluke meter... as measuring VERY small caps can be iffy, and subject to where the leads are in respect to other thigns... but...

Sounds like you have a 270pf or 470pf capacitor.  I'm guessing this is a very tiny little item?  About 3/8 inch by 1/4 inch radial leads.  Perhaps a little dark maroon or black colored item?

 

[guitarhobbyist]

Yeah its about that size. I was asking Digikey online and they were describing how to properly measure it but I don't have the equipment that they said. Something about running a current through it while metering it. How about this? If I go out and buy a 270pF cap like you suggested and measure it the same way I did before, would I get that same initial 0.36nF reading?

 

[-CB-]

possibly get the same reading

Cap meters.. are a finicky bunch when you get down really low on the scale.  Your hands and the leads... the individual meter.. they can be factors that give an "off" reading.  Ya have to sort of use some educated guesstimating

Whats it used in?

 

[guitarhobbyist]

Its for an effects pedal mod. I found a list of parts for that and one of them is a 220pF cap. I am guessing its that one. Thanks for the help.

 

[-CB-]

My cap meter adds about 19pf to every cap it measures, regardless.... so at low ranges you get a 19pf offset on the display.  Not having lots of caps available to test makes it a bit guessy.

But, say its 330pf, the circuit will still work.  It might sound slightly different (probably a bit brighter) but it will be more or less ok, and you can put in a 220pf when ya get one.