capacitors?

whats the best way to discharge and check capacitors on a motherboard/circuit board?

just want to practice for a future hobby of mine

not sure about a small motherboard capacitor, on the large ones, we short them with a screwdriver to discharge. Check them with a meter that can read microfarads.

thanks how fast is shorting them opposed to hooking up a meter or a lightbulb to it?

instant

A meter doesn't short them really. A light bulb would be longer

Or you could pull it from the board.........run some current through it, then toss it to your buddy. It will discharge then plus it's hilarious to watch them when they catch it.

I used to do that with small gas engine condensers too. It's a great practical joke.

with the typical capacitance of what you would find on a motherboard, prettymuch any kind of load will discharge them instantly. i've got a few 16,000uF caps laying around that power a single LED for less than a second before they drop to the forward voltage threshold(so 2ish volts). at that point, they're pretty harmless.

if you wanted to be really safe about it, connect a resistor between the two pins and you'll discharge them quickly in a controlled manner. anything from 100 to 1000 ohms would cover typical capacitances with no problem.

and for specifics

100 ohms at 12 volts = .12 amps(1.44 watts)
1000 ohms at 12 volts = .012 amps(.144 watts)
100 ohms at 3.3 volts = .033 amps(.1089 watts)
1000 ohms at 3.3 volts = .0033 amps(.0189 watts)

12 volts at 15,000uF = 180mC and 1.08 joules. discharged through a 100 ohm resistor, after 1 second, capacitor should be down to 6.2 volts. after 2 seconds, 3.2 volts. 3 seconds = 1.62 volts.

http://www.learningaboutelectronics.com/Articles/Capacitor-discharge-calculator.php#answer

neat calculator to test out what kind of range you can pla with.