Quick really stupid question on capacitors...

[Guest]

OK, I'm replacing the coupling caps on my "project" Magnavox 175-55 amp. The second set is .0033mF, but rated at 400v. I can get Sprague Orange drops locally, but rated at 600v.

I know this is dumb, but 600v caps will work fine in place of 400v rated caps... right?

Sorry - I know that's a really stupid question, but everything I know about electronics you could write on the bottom of my shoe with a can of spray paint.

Don

[erichayes]

Hi All,

Don, to quote God knows how many philosophers, "It is always better to ask a stupid question than make a stupid mistake". Yes, a 600 volt cap can replace a lower voltage cap as long as there are no physical restrictions. The same is true of resistor power dissipation ratings and inductor and transformer current spec's.

The only time the "bigger is better" voltage rating on caps didn't (note past tense) apply was with electrolytics. Ustabee electrolytic caps pretty much had to be matched to the voltage that was applied to them, with a 50% maximum overrating, in order for them to "form", or attain their specified capacitance. That's no longer true (I've deliberately used new-manufacture 450V caps in cathode bypass applications just to see what would happen; nothing did). The main reason for matching voltage to application now is price.

[EWBrown]

As tehy say, the only "stupid" questions are the ones that never get asked...

I typically use 600V ccoupling aps in 250-400VDC circuits, and never have any issues. Physical fit is the only issue here, if it's too big to fit in or on the board, just look around for another make/model.

Same thing for resistors, a 2W resistor is OK to replace a 1/2 or 1W resistor, just don't go the other way, unless you enjoy the smell of cooking resistors...

/ed B in NH