# Question on Circuits with Dielectric Problem

1. Feb 9, 2008

### darkspym7

Circuits with Dielectric Problem

1. The problem statement, all variables and given/known data
http://img412.imageshack.us/img412/2450/circuitgj6.jpg [Broken]
The dielectric added has the value of 3.67.
http://img504.imageshack.us/img504/5360/circuitquestionqw6.jpg [Broken]

2. Relevant equations
C=Q/V
C'=kC
Series: 1/C=1/C1+1/C2...
Parallel: C=C1+C2...

3. The attempt at a solution
So, I can find the normal voltage and charge with the dielectric in, but once the battery is removed, I am lost as to how everything balances out.

Let the capacitors be numbered: 1 for the top left, 2 for the top right, and 3 for the bottom.
Let Cxy be the total capacitance of x and y.
C12 = 1/(1/3.48 + 1/(3.67*8.8))
Removing the dielectric:
C12' = 1/(1/3.48 + 1/8.8)
Since V123 = V12, Q12 = C12' * V12

But this is not correct. Any tips on how everything balances out when you remove the dielectric?

Thanks.

Last edited by a moderator: May 3, 2017