The Pyrotechnic Qualities Of Capacitors

Ok kiddies, you know how your circuits lab instructor always said to make sure to put your electrolytic capacitors in the right way around so they don’t pop? Well, if you connect a ~25Vdc cap to 140VAC (RMS) and hold the 15-amp breaker closed so it doesn’t trip, the capacitor will not only pop, it will blow up.

Completely.

There is a loud bang (which naturally brings your instructor running, since you wouldn’t think of doing this sort of thing when he’s actually in the room), a cloud of white smoke (which smells really nice), and drifting fuzz from the stuff inside the cap. Probably some shrapnel, too, but I didn’t actually see any of that. One should also note that your instructor will probably be rather put out, due to safety concerns and destruction of school property, however small and cheap the property.

Names have been withheld to protect the very guilty. And no, I didn’t do it, although now I know why you shouldn’t. And now I can say that yes, I have seen a capacitor blow up.

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