Re: Double dielectric capacitors?

To: tesla-at-pupman-dot-com
Subject: Re: Double dielectric capacitors?
From: RWB355-at-aol-dot-com (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Fri, 09 Oct 1998 16:11:51 -0600
Approved: terryf-at-verinet-dot-com

Hi Marco, All

 Original Poster: Marco Denicolai <marco-at-vistacom.fi> 
 
 To help to remove air from my rolled capacitor (to be built) I was thinking
to
 use paper and PE as dielectric. That is
 
 ---- Al
 ---- paper
 ---- PE
 ---- Al
 ---- paper
 ---- PE
 
 Now the difficult question: if I use as dielectric two materials together,
 say:
 
 - material A, thickness tA, dielectric constant kA, dielectrict strength vA
 - material B, thickness tB, dielectric constant kB, dielectrict strength vB
 
 what is going to be the resulting dielectric constant? And the dielectric
 strength?
My comments:
 
This is what I proposed some mails ago. Teslaphiles seem to agree on this. The
paper will wick up the oil and should help displace trapped air.

The dielectric strength should go up in a linear way. (vA+vB). The thickness
shouldn´t make too much of a difference as the paper isn´t very thick. I
measured some normal laser/xerox paper. It mikes to about 3.8 mils. I don´t
know about the dielectric strength. If were a spark I would guess it would
also be linear (assuming no air), so kA+kB. 
However, in the real world I would stay on the safe side and simply ignore the
dielectric strength of the paper. This won´t hurt, only improve your chances
of the cap surviving a kickback.
 
coiler greets from germany,
Reinhard