Date: Mon, 29 Oct 2001 10:29:40 -0600
From: Jim Purcell <jpurcell@...>
Subject: Re: Digest Number 134
d,
I'd like to know, myself, why people think that the charge is stored in
the
dielectric. It's stored on the plates, the dielectric just facilitates
electron transfer.
Sorry, but the charge is stored in the dielectric. That's why the amount
of
capacitance depends in part on the kind of dielectric. A conductor will
not
store a charge, only provide a path for it. Insulators respond to the
potential
difference and the atoms get distorted in the sense that some lose or gain
electrons. Any imbalance in the atoms of a conductor equalizes when the
current
stops, not so with insulators. The fact that I can't see how a vacuum
stores a
charge doesn't alter the fact that it is the dielectric that stores the
charge.
Jim
My idea would be that the charge is stored in the electric field.
This is enabled equally by the positive plate which gave up electrons and
the negative plate which has an excess, a condition that would like a
current to flow, but is prevented by the dielectric. Various types of
dielectrics have different dielectric constants which would dictate the
thickness or distance between plates to achieve the same result when
comparing different types of dielectrics.
The first poster says a dielectric "facilitates" electron transfer.
It actually inhibits it. To facilitate would make it a conductor, and there
would be no charge.
mike g.
