>
>> >Just as a ball park reference, in my hand is a 258 pF 8KV 7A @ 3mHz. It
>> >measures 3X3X2 1/4 inches.
>> >
>> ? As I understand it, the current handling ability of mica caps
>> decreases above 3MHz.
>
>> Rich...
>
>Not according to the data I see in about a half dozen places.
? got any URLs, Tom?
> Many mica capacitors continue to increase in current with frequency,
>depending on the style of construction and value, way up into VHF.
>
>Multi-layer micas are a very common high current VHF capacitors.
? I never saw a mica capacitor that wasn't multi-layer.
>
>Mica does not become a poor dielectric at 3 GHz, let alone 3 MHz.
? Who said that it becomes a poor dielectric at 3MHz? In my collection
of mica transmitting caps, current rating is often speced at a few MHz
and/or a few hundreds of kHz. The info on derating mica above 3MHz came
from Lenk at Hiway Sales in Oceanside, California.
> .
>Especially Ruby Mica, which is used in some of the lowest ESR
>capacitors available for microwave.
? Impressive. So why isn't ruby mica dielectric used in HV caps. for
HF amps.?
- cheers, Tom
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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