Newbie capacitor question

dfish · Post by **dfish** » 21 Jul 2009, 13:41

Sorry to sound ignorant, but I've noticed capacitors of the same value come in different voltages. How do I know which voltage to get? My circuit diagram doesn't show the capacitor voltage. Thanks for any answers to this.

Silent Fly · Post by **Silent Fly** » 21 Jul 2009, 13:49

dfish wrote:Sorry to sound ignorant, but I've noticed capacitors of the same value come in different voltages. How do I know which voltage to get? My circuit diagram doesn't show the capacitor voltage. Thanks for any answers to this.

It depends on the circuit.

For capacitors, the voltage is the maximum voltage the capacitor can take before breaking.

Greg · Post by **Greg** » 21 Jul 2009, 14:09

so... for a 9 volt circuit.. a 16 volt cap is fine.
If you plan on running higher voltage, you might want to go for something like 25 volts.
Higher voltage will work the same, as long as you can fit the cap in OK.

dfish · Post by **dfish** » 21 Jul 2009, 15:19

Thanks for the info.

One more question... do all the capacitors then need to be the same voltage, or can one be 16v and another be 25v? And... can I have electrolytic, film, ceramic and silver mica capacitors on the same board? What are the differences between them? Okay, sorry, that was a lot more than one question.

Thanks.

Greg · Post by **Greg** » 21 Jul 2009, 15:47

dfish wrote:Thanks for the info.

One more question... do all the capacitors then need to be the same voltage, or can one be 16v and another be 25v? And... can I have electrolytic, film, ceramic and silver mica capacitors on the same board? What are the differences between them? Okay, sorry, that was a lot more than one question.

Thanks.

No you can have mixed voltages no problem.. you may find the ceramics and silver micas all be in the hundreds of volts... and you can have a mix of caps.. just make sure when using polarised caps (electrolytics and tantalums) that you put them in the correct way.

dfish · Post by **dfish** » 21 Jul 2009, 15:59

Thanks, man.

dfish · Post by **dfish** » 21 Jul 2009, 16:28

Sorry, but I have one more question: How do I determine the right way on a polarized capacitor? Thanks

Silent Fly · Post by **Silent Fly** » 21 Jul 2009, 16:57

dfish wrote:Sorry, but I have one more question: How do I determine the right way on a polarized capacitor? Thanks

It is written on the capacitor. Moreover, the short lead is the (-) the long lead is (+)

If you google "polarized capacitor" you get more than one link that tells you how to to determine the right way to use them.

HydrozeenElectronics · Post by **HydrozeenElectronics** » 21 Jul 2009, 18:15

I've always wondered will 9 volts really blow out a polarized cap if it's wired wrong? even if it is a much higher voltage cap? And if so what is the danger to your amp if you blow the output cap on your fuzz pedal.

Reason I ask is I have a good sounding pedal I built a while back before I new any better. It sounds really good so I don't want to take it a part but...If it might blow my amp some day then yes I'll switch it around the right way.

thanks