# Plate cap

1. Sep 30, 2004

### galipop

Hi All,

I've been doing a few problems with plate capactors and I have this new one which introduces a voltage U. I haven't seen an example with a voltage befopre so I'm not sure where to start it. I'm hoping someone could start me off.

The problem goes like this: Find the electric field between the plates when a voltage U is applied to the cap. The cap consists of 2 plates (surface area F, distance d apart). Between the plates is a conducting plate of charge Q.

Thanks...

2. Oct 1, 2004

### Chi Meson

THe capacitance is found as (epsilon)(area)/(distance). Also capacitance is defined as the ratio of (charge)/(potential). Lastly the relationship with the electric field is E=(potential)/(distance).

I think (someone check me on this) The charged conductor in between the plates will add to the electric field of the capacitor,(in the manner of an infinite charged plane) so there will be a different value for the field above and below this conductor, since it will add on one side and subtract on the other.