Date: Wed, 23 Feb 2011 10:51:55

Author: Cliff Bettis

Subject: Re: Tin Foil Capacitor



I don't know of a simple way to explain what goes on in a real dielectric.
The usual treatment defines the polarization and displacement vectors but
generally omits the discussion of the imaginary components of the dielectric
constant into whose realm we descend when discussing the dissectible
capacitor (frequency dependence of the dielectric constant). I know faculty
members, particularly theorists, who avoided the demonstration because they
knew "here be dragons" ;-)


-----Original Message-----
From: [] On
Behalf Of Paul Nord
Sent: Wednesday, February 23, 2011 10:38 AM
Cc: Paul Nord
Subject: Re: [tap-l] Tin Foil Capacitor


How do we respond to Jerry's question? Given the numerous methods by which
a dielectric functions, why does a capacitor work at all?


On Feb 23, 2011, at 9:34 AM, Cliff Bettis wrote:

> Paul,
> Dielectric materials vary widely in their properties (linearity,
> dependence, time dependence, breakdown field and probably others I am not
> aware of). This is why you find capacitors with a variety of dielectrics
> (glass, paper, mica, ceramic, oil and air). So what happens depends on
> kind of dielectric you use. In the standard dissectible capacitor
> demonstration, the dielectric is given a polarization that makes it
> an electrets. If you use a quartz glass or just air for a dielectric, this
> doesn't happen (See Freier and Anderson Ed-3).
> Cliff

From Wed Feb 23 11:58:10 2011