Re: [MEG_builders] Explinations of Relaxation parameters
- Hi Michael,
----- Original Message -----
From: Michael Couch <cmichael_couch@...>
Sent: Tuesday, October 02, 2001 7:33 PM
Subject: [MEG_builders] Explinations of Relaxation parameters
> Had to stop right in the middle of your excellent explination email and
> or observe this...
> If the current is flowing even though the dielectric has not been
> breached... then current is certainly some weird animal. Is it passing
> trough the dialectric even though the electrons don't? Or is it flowing
> backward in the circuit through the earth to the opposite plate from the
> positive plate of the capacitor?
The current is flow of electons in one direction, and flow of ions in the
other direction. Beacuse the ions are massive (heavy) they flow very slowly
compared to the lightweight electrons, so it is mostly electron flow that
makes up current. When a capacitor is being charged the electrons stack up
on one plate, whie at the same time are depleted from the other plate, so
there must be a flow for this to happen. When the capacitor is fully
charged there is no longer a flow.
The electron current does not flow through the dielectric, and this break in
flow continuity causes problems with some math (like Kirchhoff's Laws), and
why there is continuity across this break of the magnetic field which
encircles the wire. To get over this problem physicists use a fix (first
invented by Maxwell). They pretend that current does continue to flow
through the dielectric, but since this is "pretend" current and not electron
flow they give it a separate name. This is called "displacement current",
and is directly related to the rate of change of electric field across the
dielectric. What really happens is that the changing electric field causes
the magnetic field to remain intact, but some people find it easier to think
of the magnetic field coming from the displacement current, just as it does
around the wire.
Then are we dealing with something like a balloon filled with air where we
squeze here and it bulges there but returns to its original shape? If so I
don't understand why the relaxation thing won't work and work well? Even if
the only gain is the difference between ion flow timing and electron flow
timing to capacitor filling.
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