# Leakage resistance in a capacitor

1. Jan 15, 2009

### Dan_tanner

1. The problem statement, all variables and given/known data

I am trying to find the relevent equation to to solve the following problem,

RL= leakage resistance measured across the dielectric

A 100pF parallel-plate capacitor has a mica dielectric of relative permittivity [tex]\epsilon[/r]=12 and a resistivity of \rho=10^14\Omega m.

I want to calaculate the leakage resistance of this capacitor.

2. Relevant equations

3. The attempt at a solution

The previous question wanted to know the area and distance between the plates of the capacitor, i think that this has something to do with the answer to the question,

I have solved this!!

I think i have all the relevent information to have an atempt at the answer but dont know and cant find the equation,

I am not sure if Resistance R = rhol/A has anything to do with it because it states resistivity is \rho = 10^14 \Omega m

this has thrown me??

I cant find anything that points me in the right dierction in my books or course work.

2. Jan 15, 2009

### Defennder

You're missing a needed formula here which gives you the capacitance of an ideal parallel plate capacitance. Use that and your resistance formula to find R.

3. Jan 15, 2009

### Dan_tanner

Hello Defender,

Thanks for the reply, Im still not sure, i dont realy understand what you are on about? Im all mechanical ad never had to do electrical before.

Are you on about C= epsilon r epsilon o * A / d

If so, this is the formula for finding C which is in farads which i have already been given as100pF

4. Jan 15, 2009

### Defennder

You can transpose the formula to to obtain an expression to help you calculate resistance from the other formula.

5. Jan 6, 2010

### Kev1n

Dan,

Did you ever get the formula as I am stuck on asimilar question