Identifying polyester capacitors

Nav · 2007-07-30 16:11

I have a selection of polyester capacitors - the rectangular, yellow ones about the size of a grain of corn.· I understand the 3 digit values printed on them are the value represented as·first digit, second digit, power of 10 expressed in picoFarads.· So 103 is 10,000 pF = 10 nF = 0.01uF.· What's confusing me is that I have a number of them labelled .1K63· I know the K stands for 10% tolerance and the 63 is the maximum voltage but what is .1 ?· Surely, it cannot possibly be 0.1 pF ?· What is the correct value of this capacitor ?

Nav · 2007-07-30 16:18

I forgot to point out that my capacitors are not metallised polyester capacitors. They are described as miniature polyester capacitors, if the distinction makes any difference to the type of coding used. Here's a link to them;
http://www.rapidonline.com/productinfo.aspx?kw=polyester capacitor kit&tier1=Electronic+Components&tier2=Capacitors&tier3=Polyester&tier4=Miniature+polyester+capacitor+kit&moduleno=62509

Forrest · 2007-07-30 23:44

Just a guess, but I'd say .1 uF

Nav · 2007-07-31 12:34

Forrest, thanks for your reply.· I did a bit of Googling and, although I couldn't find anything conclusive, it does appear that this particular value is stated in uF rather than nF or pF.· So, yes, I guess it is 0.1uF.· Thank you.

On a related point, is there a way - some sort of gadget - to check the value of a capacitor when one isn't sure of the value ?· I don't think multimeters offer this feature.· I know you could contrive some sort of RC circuit but·I would guess it wouldn't be particularly accurate and you have to have a different one for each capacitance range.

Bruce Bates · 2007-07-31 14:15

Nav -

Here is a hand held capacitance meter specifically designed for sorting through capacitors:
http://elexp.com/tst_3100.htm

That is just one of many that are available.

Regards,

Bruce Bates

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parts-man73 · 2007-07-31 15:29

Some of the better multimeters do have the ability to test or determine the value of capacitors.

Here's a website I have bookmarked on my own computer for looking up capacitor codes.

www.electronics2000.co.uk/calc/calccap.htm

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Brian

uController.com - home of SpinStudio

Nav · 2007-08-02 15:32

I found a reasonably priced multimeter on the web (from the electronics 2000 link) that can measure capacitance. Thanks guys for your help.

Identifying polyester capacitors

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