# How much charge can a capacitor hold?

Discussion in 'General Electronics Chat' started by impaJah, Aug 3, 2012.

1. ### impaJah Thread Starter New Member

Aug 2, 2012
18
0
Is there a way to calculate how many coulombs of charge a given capacitor can store given a certain time interval that can be derived from its farad rating? For instance, how many coloumbs can a 47uf cap hold after 2ns of 3 volts? What about a 1uf? Or a 500pf?

If it can't be derived from it's rating, is there another convenient way to figure this out?

2. ### MrChips Moderator

Oct 2, 2009
12,227
3,279
The charge Q in coulombs is the capacitance C in Farads multiplied by the voltage in Volts.

Q = C x V

For example, 1μF x 5V = 5 μC

3. ### impaJah Thread Starter New Member

Aug 2, 2012
18
0
Thank you MrChips!!!

4. ### crutschow Expert

Mar 14, 2008
12,505
3,060
The capacitor voltage (Vc) after an interval of time is determined by the voltage charging source (Vs) and any resistance (R) in series between the voltage charging source and the capacitor (C). The capacitor voltage will rise exponentially after the voltage is applied and will be equal to Vc = Vs(1 - e$^{-t/RC}$) where t is the elapsed time.

From the capacitor voltage you can then calculate the charge using the formula MrChips gave you.