Capacitor Voltages?

[Wild Zebra]

I think I know the answer to this, but not sure. Do I just need to make sure the caps are rated over 18 volts? I just figure since its running off 2 9v(18v) I know from building stompboxes you have to make sure all
caps are over 9v typically recommend 16v.

thanks

[mosc]

Caps from power to ground will only have 9V across them. Caps in the internal parts of the circuit could have even less, depending on the circuit. The designer should specify the voltage ratings and following those specs is a usually the best idea. Using 18V is a good rule-of-thumb if you have nothing else to go on.

Caps inside the power supply circuits are somthing else. I once built a 15V power supply and wired the electrolytic capacitor in backwards. It worked fine for about two years. Then, one day it blew up. The top poped off and a violent stream of hot gas shot up with a horrible whistling noise. If my face was over that powersupply I might not be writing this today. Wow, it was powerful and deadly. Be carefull with polarity on those electrolytics in the power supplies.

[Wild Zebra]

Thanks MOSC. All I had were 50v electrolytic anyway. They're alittle
big, but I won't have to worry about any power issues.

thanks again

[mosc]

Electrolytics are good to use for power supply filters, but you can get unexpected results if you use them in a signal path. This is because they are polarized capacitors.

The best way to learn about these things is to do what you are doing - ask people and then try stuff yourself.

[autoprod]

By mistake I received a 1n cap at 600V, whereas I wanted a 16V. Would my 5V circuit care at all? Beside the bastard being bigger than anything else on the board?


-autoprod

[mosc]

I used to work for IBM consulting. Here's how they would answer such a question:

"My guess is that it will work, unless it doesn't."

[Macaba]

Your 600v 1nf cap will work fine, its just 10 times bigger than you need it!

[autoprod]

Excellent. Thanks for assuring me - and saving me the de-soldering.