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Shorting Capacitors? Answered

Hi Guys,

Recently I found a person selling a power supply for $3 and I thought why not to buy it and salvage the components. I was wondering will it be safe to short the huge capacitors in the power supply?

Thanks :)


Sure. I short caps all the time using a well insulated screwdriver. Just don't use the tip. I used a knife once as a teen. On the sharp edge cause it was a Gerber Gator which had a coating on the blade so only the edge was exposed. Ended up spot welding the blade to the capacitor lead.

LOL Nice! :D I ruined a knife's edge the same way with photoflash capacitors. It was a cheap knife I did not care about, it needed a lot of sharpening to buff it out.

No! use a resistance of value > 100K 1Watt instead. You can use some components as in here https://www.instructables.com/id/Burning-Laser-with-Joule-Thief/

I can not recommend to produce a dead short to discharge a capacitor - unless you don't need the cap or the tool anymore.

A dead short can cause sevre damage to the cap due to the high amps going through it.
Best way is to discharge them with a resistor.

For mains voltage or higher I use a 1 mega Ohm resistor below mains voltage 100 kilo Ohm.

Connect the resistor and leave it connected for about 15 minutes and even a massive cap shall be empty.

Of course you can simply measure the voltage on the cap to check if it is charged or not ;)