[DAB_Design]

When checking a problem with one of my geckos, I acidentally hooked my capasitor back up backwards(70uf 63V). It lasted a few seconds once power was applied (flame2). Anyway, I went to the big city today to pick up a replacement. First stop was radio shack. They didn't have any big enough. So they sent me down the road to a smaller electronics only place. They didn't have a 63V, but the lady said I could use a 100V in place of it.

So is that the case? Voltage can go higher on capacitors?

Oh and by the way, those things are nasty when they blow. It shot smoke and some liquid stuff about 3 feed in the air. Didn't smell too good either.

[Al_The_Man]

Yeah, they go off like a cannon sometimes, higher voltage rating is OK, BTW the capacitive tolerance on most electrolytics is often given as within +100% -0.
Al

[trilect]

you can use any higher voltage rating as long as the capacitance is the same, just make sure you have room for it.

[DAB_Design]

Yeah, they go off like a cannon sometimes

If that little thing shot 3 feet in the air, I'd hate to see what the 1F cap I had in my car would do. It was just a bit bigger. :idea:

[Al_The_Man]

Incidentally on a similar note, if you have had large electrolytics sitting on the shelf for a long time, especially high voltage ones, it used to be recommended practice to apply a low voltage for a period of time and gradually increase the voltage over time before placing them in service to prevent blow ups, something to do with the chemical composition changing over time without a charge.
Al

[ESjaavik]

@Al: Over time they dry out. Good prctice is not to stoop over it when applying voltage to them! If they are large, it may be worse than the need for new underwear!

Don't underestimate the force when they go off, the gunk coming out the open end is nothing compared to the can shooting off in the opposite direction. I know, many years ago a ham friend of mine said on the air that he heard a strange sound in his PA. Then he went off air. Later he told me he put his ear down to the PA, and luckily there was a lid on it. He did this just as it went off, and got a bit scared to put it mildly! I was shown the mess, and can understand his reaction.