changing dielectrics in a capacitor (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Sun, 18 Jan 2004 23:01:41 -0500
From: Alfred Erpel <alfred@xxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: changing dielectrics in a capacitor



Howdy all,

    Imagine a parallel plate capacitor where all metal plates of the
capacitor are fixed, and you can rotate the dielectric material with a k=10
from full coverage between the metal plates to no coverage where the new
dielectric is air k=1.

    Lets say we start with the air as dielectric and the capacitor is rated
at .001µF and charged to 10,000 volts.

    When the k=10 dielectric material is rotated totally into place to
replace the k=1 air, what happens?

I will speculate:

Q=C*V wants to stay the same so as the capacitance increases to .01µF the
voltage drops to 1000 volts.

The capacitor now has 1/10 of its original energy.  If my speculations are
correct, what happened to the 9/10 of the energy that went away?  Does the
new dielectric want to get "sucked" in?

Regards,
Al Erpel