charging capacitors

[matthew47]

I have a question, how can i chargw up my capacitor to full? I tried simply connecting it to a battery and that didn't work because I think it only charged to the battery's power level, when it should go to 400 v. Do I have to put a resistor in series when charging or what?

 

[Roff]

A capacitor will only charge to the voltage of the battery you connect it to. The voltage rating - 400 volts in your case - indicates the maximum safe voltage you can charge your capacitor to. If you try to charge it to a higher voltage, the capacitor may be damaged.
With large-valued capacitors and batteries with high current capability, you should put a resistor in series to limit the peak current. Otherwise, you can get arcing and accompanying hot metal splatter.

 

[matthew47]

so you're saying that i cannot do anything unless i find a 400 v source?

Oh, wait, how would i convert the voltage from a wall plugin to DC instead of AC?