RE: Cap W/ Electret

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Gary.Lau-at-compaq-dot-com>

I see a couple of problems.

First, polycarbonate and acrylic are fairly lossy dielectrics compared
to polyethylene or polypropylene.

More importantly, by "freezing" a static charge into the dielectric, it
would then have a DC bias.  If an unmodified sheet of the material had a
nominal static breakdown voltage rating of 10kV and you imparted a 5kV
bias into it, then it could only withstand a 5kV AC oscillation, whereas
an unmodified sheet could withstand 10kV.. 

I'm not sure what the goal of the electret is in this application.
You're not going to be getting any "free energy".

Gary Lau
MA, USA



>Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<Michael.Day-at-USPTO.GOV>
>
>Greeting all,
>
>I was wondering if any one has had any experience with 
>home made capacitors using an electrets for the dielectric?  
>A typical electret is a dielectric, usually a polar polymer such as 
>polycarbonate or acrylic resins, that has been heated to its 
>softening temperature, and an electric field impressed across 
>the material.  On cooling, the electric field is frozen in the
dielectric.  
>Such a capacitor is somewhat unusual in that it tends to charge 
>itself.  (Watch out, they can bite.)
>
>I've been considering making one for my coil, and was wondering 
>if anyone had any experience with them, or had any comments 
>regarding utility, for example, failure rate of polycarbonate or
acrylic 
>resins.
>
>-MHD