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capacitor replacement in non-psu circuit.

jvdbossc

Jan 27, 2012
36
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Jan 27, 2012
Messages
36
I learned that when replacing a cap you need to use the same values, and also have to use the same type of capacitor depending on what it is used for. However they told me that the voltage rating can be higher.

I came across a repair project from a good friend and two unrelated sources gave us the advice not to put in a 220uf 16 V capacitor instead of a 220uf 10 V.

Then I asked why, and both persons told us that the 10V protects an nearby IC (expensive) if it gets 13.8V. Is there some truth in it or is this ...?

I just want to know in general, cause I often com across old CB and HAM equipment that needs some caps done.
 

Old Steve

Jul 23, 2015
734
Joined
Jul 23, 2015
Messages
734
I learned that when replacing a cap you need to use the same values, and also have to use the same type of capacitor depending on what it is used for. However they told me that the voltage rating can be higher.

I came across a repair project from a good friend and two unrelated sources gave us the advice not to put in a 220uf 16 V capacitor instead of a 220uf 10 V.

Then I asked why, and both persons told us that the 10V protects an nearby IC (expensive) if it gets 13.8V. Is there some truth in it or is this ...?

I just want to know in general, cause I often com across old CB and HAM equipment that needs some caps done.
No truth whatsoever.
 

Old Steve

Jul 23, 2015
734
Joined
Jul 23, 2015
Messages
734
I'd better explain further - the voltage rating is simply the maximum voltage that the capacitor can safely handle without damage. Nothing more. It has nothing to do with limiting voltage.
 

AnalogKid

Jun 10, 2015
2,884
Joined
Jun 10, 2015
Messages
2,884
That advice sounds like either they think the capacitor will protect the device from overvoltage by failing into a short circuit when the condition occurs (it will NOT), or that they are talking about a zener diode rather than a capacitor. Either way, this is not the way to protect a circuit from overvoltage. If that is a real concern, give us more details about the circuit and we'll give you better advice.

ak
 
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