> The time constant is interesting. Since the time constant has to a certai=
n
> value for a certain frequency, is it better to have a high R and low C or
> high C and low R?

Large general purpose electrolytic caps tend to have high leakage. They
wouldn't be suitable for long accurate RC times or as filter caps on a nW
battery-powered board for example

Ceramics and other non-polarised - mylar, PE etc - and low-value
electrolytics [including tantalum] would have no or no significant leakage

Joe=20

--=20
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