how do you charge a capacitor

**ssa_whiskey** · 12-05-2003, 03:05 PM

weve got a 1 farad capacitor here in our physics room, and were wondering how we need to charge it up, we do have a dc generator, but r just wondering the best way to charge up this beaut,
notes: do u just connect the pos to neg, or what
many thanks

**telekineticfool** · 12-05-2003, 03:54 PM

To do what? 1 farad will kill ya!

Not sure I should tell you...hehe...but just connect dc positive to the positive and dc negative to the negative...and turn up the voltage as high as you want, i guess. And let it sit there. For a few minutes.

To discharge it, short the terminals Obviously don't touch both at once or you'll get zapped...even a small capacitor (disposable camera flash?) can leave small 3rd degree burns at the arc points. Don't hurt yourself!

**hijinks21** · 12-05-2003, 03:57 PM

ya my physics teacher grounded a disposable camera once by mistake. oh man was the funny. he wasn't perm injuried but it through him back a bit.

**telekineticfool** · 12-05-2003, 04:04 PM

we had one rigged up at Scout camp one time...had people put their finger on the contacts...everybody did it (me included) and the rest of the week everybody had two little tiny black charred dots burnt into their finger

**hijinks21** · 12-05-2003, 04:09 PM

in class we used one of those big *** Electrostatic Generator Balls and would create a human chain and at the end of the chain we'd have a metal rod with a sign on it saying touch me. It was funny when a freshman would walk by and not touch it but it would arc and zap him. Hah.. of course it felt like a tennis ball going through our body but all the more fun

**shakes** · 12-05-2003, 04:31 PM

remember that once the capacitor is fully charged it will act as a short circuit ... so you need to have some other form of a load in the curcuit else you may short out the PS.

caps charge in no time and will discharge just as fast when part of a circuit.

**Ricky327** · 12-05-2003, 04:37 PM

Careful with big capacitor, connecting them up wrongly build alot of pressure inside. They do explode, big enough to kill you.

**Pudge** · 12-05-2003, 05:26 PM

People must be getting dumb, at least every year for the past 3 in my classes, someone has brought a camera to rip it open and shock themselves as well as anyone that volunteers, unless the person is an idiot and and sticks it on random people. Good times, stupid people.

**aleromaster** · 12-05-2003, 06:34 PM

DO NOT just sortoutthe terminals to discharge. Use a 10 OHM resitor.

**telekineticfool** · 12-05-2003, 07:20 PM

Originally Posted by shakes

remember that once the capacitor is fully charged it will act as a short circuit ... so you need to have some other form of a load in the curcuit else you may short out the PS.

caps charge in no time and will discharge just as fast when part of a circuit.

caps charge proportional with their time constant, which is based on the resistance of the circuit, and a charged cap is an open circuit, not a closed one, so you'll be in no danger of shorting anything.