# capacitor

Discussion in 'General Electronics Chat' started by TAKYMOUNIR, Feb 4, 2013.

1. ### TAKYMOUNIR Thread Starter Active Member

Jun 23, 2008
351
1
how the capacitor store energy

2. ### DerStrom8 Well-Known Member

Feb 20, 2011
2,373
1,353
....Is that the whole question? Having over 200 posts, I expected you'd have learned by now that we need fully-worded, clear questions in order to give good answers.

Anyway, capacitors do not store energy. Simple as that. Instead, they store charge.

There's a nice little write-up here: http://www.physics.sjsu.edu/becker/physics51/capacitors.htm

3. ### TAKYMOUNIR Thread Starter Active Member

Jun 23, 2008
351
1
I think my question is clear ,any way thanks,but the capacitor store energy=1/2 cv^2

4. ### crutschow Expert

Mar 14, 2008
21,375
6,124
That would seem to an overly restrictive definition.

Capacitors actually store both, of course. They store energy by storing charge as determined by the voltage applied to transfer the charge.

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5. ### DerStrom8 Well-Known Member

Feb 20, 2011
2,373
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I stand corrected.

6. ### MrChips Moderator

Oct 2, 2009
18,187
5,709
Not quite. Charge, voltage and capacitance are all inter-related, much like Ohm's Law.

$V = \frac{Q}{C}$

Hence the energy stored in a capacitor of a given capacitance C can can be determined entirely from charge Q,

$E = \frac{1}{2}\frac{Q^2}{C}$

or from voltage V,

$E = \frac{1}{2}CV^2$

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7. ### DerStrom8 Well-Known Member

Feb 20, 2011
2,373
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Yup, I remember seeing that before, specifically the last one. Not really sure what I was thinking.

Guess it's been too long since I did any math relating to electronics!