Capacitor Volage Calculation

Thread Starter


Joined Aug 24, 2007
I was wondering how you would calculate the voltage between two plates. Let's say one had a charge of 1 coulomb (6.24150965×10-18 electrons on it) and another plate with just the opposite charge. (a capacitor, lol )

Also how does distance effect the voltage and energy storage?

It seems kinda hard to figure this out or find out how to.

Also how would you calculate the voltage between the two plates if only one of the plates was charged and the other was completely uncharged. Plate A 1 Coulomb and Plate B 0 Coulombs of charge. (Doesn't really matter how it happened, it's just like that for the sake of argument.)


Joined Mar 14, 2008
To determine the voltage you need to calculate the capacitance between the two plates. This is determined by the plate area, the distance between them, and the dielectric constant of the material between the plates. Here's a calculator to do that.

The voltage on a capacitor is V = Q/C where Q is in coulombs and C is in farads.

Energy stored on a capacitor equals 1/2 CV\(^{2}\) with the energy in joules.

It's not possible to charge only one plate of a capacitor. The two plates always have equal and opposite charge. Otherwise it wouldn't be a capacitor.