Type of Capacitor?!?! Help please!?

Question

I have a bad capacitor on a circuit board that needs to be replaced. It is a small, blue, ceramic capacitor. I need to know whether it matters or not what type of capacitor I get to replace this. As long as its about the same size, it should work right? I don't know the value of the capacitor because the outside is all ruined and I can't read it, but as long as I get a high value capacitor it should work right? I don't know much about capacitors, but I'm guessing it can't hurt to go too high right? There is a guy selling what he says are custom made capacitors, but shouldn't I just be able to go to Radioshack and get a capacitor that looks about the same as the bad one i have now?

The bad capacitor looks much like this one at Radioshack (except its blue) --
http://www.radioshack.com/product/index.jsp?productId=12579917

So, if I bought this kind, would it work?

Answer 1

Impossible to say without knowing what its function is in the circuit. If it's a decoupling capacitor across the supply rails then its value is quite flexible, in fact the circuit will probably work without it. If it's part of an oscillator or tuned circuit then the value could be absolutely critical.



The only blue capacitors that shape that I have seen are high voltage ones, rated at >1000V. If it is one of these then if you replace it with the one from Radio Shack (rated 50V) you will probably just get a blown capacitor as soon as you switch it on.



More information needed, like what the circuit board is.

Answer 2

I've seen blue MOVs (Metal Oxide Varistor, used for transient overvoltage suppression). It would be thicker than the disk cap you pointed to, though.



You're going to be a lot better off if you can come up with a schematic or board parts layout.

Answer 3

There is no way to tell, but it is highly unlikely it will work.