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Re: parallel capacitors

Jayasanker_J wrote:


Sometimes we use a big and small capacitors in parallel
for filtering purpose, for example in power supplies a 10uF
and 0,1uF. In theory, 10 and 10.1uF looks an insignificant
difference. Perhaps the small caps work better at high frequencies?


JohnD replied:

Yes. Take a look at the mfgr's spec sheets.

What kind of frequencies are important in a power supply? Not
very high, certainly below 1200 Hz in common cases. Therefore
the explanation is not satisfying. Why should 0.1uF work better
than 10 uF at f=1200 Hz? Are voltage ratings identical?