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Dissipation factor of capacitors

eem2am

Aug 3, 2009
429
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Aug 3, 2009
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429
hello,

how can you tell what is the dissipation factor of these capacitors at 100KHz,?

http://www.produktinfo.conrad.com/d...01-en-METALL_POLYESTER_KONDENSATOR_0_1_UF.pdf

...on page 12, the datasheet only says the dissipation factor at 10KHz or 1KHz,....this is not much use since my SMPS switches at 58100Hz.

i wish to use the 330nF, 400V one close up to the power switch loop, so as i don't draw so much ripple current from the electrolytic cap.
 

shrtrnd

Jan 15, 2010
3,876
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Jan 15, 2010
Messages
3,876
If the data sheet doesn't show a graph to find your freq, email EPCOS, and ask them about your specific application.
I use a lot of metallized polyester for RF applications, so I assume you're ok. But it's
possible the construction of this particular cap is not designed for the frequency you're planning to operate at. The manufacturer can tell you if this is the cap for you, or recommend a better model.
(like ceramic maybe?)
 

Militoy

Aug 24, 2010
180
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Aug 24, 2010
Messages
180
I don't know if you've looked at Epcos' general data for film caps yet - but it has a pretty good explanation of the effects of higher frequencies on these caps. the issue isn't so much that you are limited to 10 KHz operation - that's just the standard test frequency for higher value polyester caps. I think their stacked polyester caps are pretty good at HF. Look over their charts - and if you are still concerned - consider going with a polypropylene or ceramic cap instead.

http://www.epcos.com/web/generator/...__en.pdf;/PDF_GeneralTechnicalInformation.pdf
 
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