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mica capacitor substitutes
(Johan Wagener) wrote in message . com...
I simply can't buy silvered mica caps in south africa. They cost more
than the output transistors.
I need them for an amplifier project.
What do I do?
You didn't mention why you're looking specifically for silvered mica,
nor what ratings (capacitance, voltage, tolerance). Likely candidates
are C0G (NPO) ceramics and polypropylenes. The ceramics give very
good stability, but that's not likely needed in an amplifier. If it's
for frequencies less than a couple MHz, polypropylene should work
well; they have low dissipation factor and can handle fairly high
currents. If they will be handling much current, the polyprops should
be much better than polyester (Mylar). If it's for high RF current,
there are transmitting-type capacitors that can do the job, but they
won't be cheap, most likely.
Paul: Polystyrene are absolutely awful to deal with in automated
assembly processes. They can't take the heat. And there are other
caps that work fine that cover what needs to be done. That's why.
Cheers,
Tom
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