# Capacitor information

Discussion in 'General Electronics Discussion' started by John04, Jun 20, 2013.

1. ### John04

1
0
Jun 20, 2013
What is the minimum size of a capacitor that will produce 100-200 joules?

2. ### Number

65
0
Jun 9, 2013
Here.

Play with values, see what you get. Or just simply set your Joules to 1-200 and solve for capacitance.

3. ### (*steve*)¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥdModerator

25,480
2,828
Jan 21, 2010
this big --> <---

(I give you the flippant answer because if you understood 1/2CV^2 you would realise the question is almost meaningless)

It makes some sense if you want to get into a discussion about power density of capacitors vs batteries, but I do not sense that is the purpose of your question.

4. ### Number

65
0
Jun 9, 2013
There still exist an equation nonetheless...

For C...

EDIT:
I suppose I should have a reference too...

Here

Last edited: Jun 21, 2013
5. ### (*steve*)¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥdModerator

25,480
2,828
Jan 21, 2010
Still, the question is meaningless.

What do you mean by small? If you mean a small capacitance then you can solve the equation for any arbitrarily small capacitance by selecting an appropriately high voltage.

If you mean small in size (or mass) then that's an interesting energy density question because the capacitor will (for a given style) increase in size as the voltage rating and/or capacitance increases. Whether a low voltage supercap or a high voltage capacitor wins out is an interesting question.

6. ### Number

65
0
Jun 9, 2013
What's the smallest size you could realistically go? 0402? I don't think you can even get a package of capacitance smaller than that though. Imagine soldering that...

7. ### (*steve*)¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥdModerator

25,480
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Jan 21, 2010
You can go to 01005. They look like grains of salt (only smaller). If you could find one that could store 100J of energy I'd eat my keyboard though.