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Old March 23rd 04, 09:41 AM
Roy Lewallen
 
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Tam/WB2TT wrote:
Roy,

We were talking about bypass type ceramics. See the 3/20 10:13AM posting.
BTW, I think with SM you are pretty much forced into using ceramics.

Tam/WB2TT


Perhaps you were talking about bypass type ceramics, but the posting I
responded to:


Yes, ceramics are *hopeless* for tuned circuits; I wouldn't trust the
black tipped ones, either. You can't beat silver mica but they're a
bit hard to find and expensive.


made no such qualification, and even specifically mentioned "black
tipped" (usually NPO) capacitors.

As far as I know, silver micas are getting pretty rare, except maybe for
very high power, high current RF applications, if they're being used for
even that any more. I doubt if they exist as surface mount parts. The
reason silver micas are hard to find and expensive is that they've been
made obsolete for nearly all applications by generally superior ceramic
types.

Roy Lewallen, W7EL