# a simple question about capacitor

Discussion in 'General Electronics Chat' started by fankoushat, Mar 9, 2010.

1. ### fankoushat Thread Starter New Member

Mar 8, 2010
17
0
Hi,

If I told you that 1 coloumb has been stored in a capacitor, does this mean, + 1 q on one plate and -1 q on the other? or +0.5 q on one plate and -0.5 on the other?

Thanks

2. ### kkazem Active Member

Jul 23, 2009
160
26
Hi,
This is a fairly simple problem. The answer is that there is indeed +1q on one plate and -1q on the other plate. If the capacitor is a 1 farad cap, then there would be a potential difference (or more simply, a voltage) of 1 volt across the capacitor's terminals by the formula: , C=q/v, where: C = Capacitance, q=charge, and v=volts. The same 1 coulomb charge would exist on both the positive plate and on the negative plate. This is so by the definition of charge, which is that 1 coulomb = the amount of charge thru a conductor with a current of 1 ampere in 1 second. When charging a cap, the same current goes into both plates, thus, an equal but opposite charge exists on the two plates, but their value will be equal in the example I mentioned above.

Regards,
Kamran Kazem

3. ### fankoushat Thread Starter New Member

Mar 8, 2010
17
0
Thanks alot for the reply.