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Re: Natural RF suppression?
>> What RF suppression characteristic? Are you saying different metals
>> favor conduction at different frequencies? I don't think so.
>>
>> Gary Lau
>Heres a question. If aluminum is not a poor RF conductor, then why is it
>usable in a capacitor? I would think that the capacitor would be
>subjected to the same RF the rest of the coil would.
>
>Chris
My original reply considered only the use of aluminum in a gap, where
resistive skin-effect losses would be neglegable. Use of aluminum in
primary coils or ground rods and ground leads is another matter and
losses may indeed be significant.
But your point about using aluminum in caps is interesting! Perhaps in
commercial caps, the surface is treated to permanently exclude oxidation,
the source of skin-effect resistance? In parallel plate caps and
extended foil caps, the current is spread out across many wide plates,
all wired in parallel, so the effective skin-effect ESR is very low.
But for end-terminated rolled caps, you may be on to something. Or it
could be that the typical cap plate width is wide enough that skin-effect
resistance is still insignificant.
Gary Lau
Waltham, MA USA