On Tue, 04 May 2004 23:52:19 +0100, Paul Burridge
wrote:

On Tue, 04 May 2004 20:19:33 GMT, Joerg
wrote:

Hi Johan,

Can't you use polyester or other film type caps? Or maybe if you need a
lot of them order internationally from Digikey or one of those places?
When I lived in Europe I sometimes had stuff shipped from the US and it
wasn't a big deal unless you want fast airmail service, but even then it
was ok for smaller parts.

For small qties my solution was very often to scavenge them out of an old
radio or TV. One that was at least 20 years old because the new ones only
have ceramics and electrolytics.

Anyone know why it is that mica and polystyrene types are becoming so
hard to find? Is there a shortage of mica and polystyrene??

Somebody in Japan, I think, quit making the polystyrene film. There's
still lots of mica in the ground, but these caps are labor-intensive
to fabricate, and NPO ceramics work as well (better, maybe: mica has
nasty dielectric absorption.) I think some big transmitting caps may
still be mica.

Mica is still used to insulate the heater elements in toasters, last
time I looked. Somebody does make surface-mount mica caps, I think!

John