On Fri, 3 Dec 2004 18:22:28 +0000 (UTC), Stewart Pinkerton
wrote:

On Fri, 03 Dec 2004 15:26:46 GMT, (Don Pearce)
wrote:

On Sat, 04 Dec 2004 02:17:42 +1100, Patrick Turner
wrote:

Two things:
Teflon is not a great dielectric - why would you do this?

Teflon's Dielectic Constant is actually quite good, really, go look at the DC
tables.

What on earth is a "good dielectric constant"? And it is nothing to do
with Er that makes teflon poor, it is the charge retention.

Ahhh. I was as puzzled as Patrick by your remark, as Teflon is
generally regarded as just about the *best* dielectric for caps and
cables. Charge retention, while the bane of the sample/hold designer,
is simply not an issue with a conventional a.c. signal.

Mechanically it is hard to handle, and electrically it is actually not
as good as polypropylene. There isn't that much in it, though.

d

Pearce Consulting
http://www.pearce.uk.com