> OK, enlighten me. What is the difference between 'mica' and 'ruby mica' as
> materials??
They are several minerals from the mica family.
Ruby mica is a mica that has much better loss tangent than pther
micas.
The worse micas I find listed are better than some of the best
ceramics, particulary as the test moves up to UHF.
Rich's statement that mica has reduced current handling above 3
MHz is not true, except with specific capacitors than have poor
internal layout. Some capacitors, but nowhere near all of them,
have too long a path along the conductors inside, and so the
current "bunches up" in small areas of the component. That's one
effect that reduces current rating as frequency is increased.
With a mica cap, check the factory rating. It would be unwise to
conclude they all handle reduced current above 3 MHz as Rich
suggested.
> 73
>
> Peter G3TZP
>
>
>
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>
>
73, Tom W8JI
w8ji@contesting.com
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