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capacitor voltage rating


RDR

#22966

capacitor voltage rating | 10 January, 2003

Does anyone know what the voltage ratings on ceramic caps is related to? Would it be safe to use a 50V cap instead of 25V for .01uF X7R bypass/filter caps?

Thanks

Russ

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mantis

#22971

capacitor voltage rating | 10 January, 2003

Hi In selecting or substituting a capacitor for use, consideration must be given to (1) the value of capacitance desired and (2) the amount of voltage to be applied across the capacitor. If the voltage applied across the capacitor is too great, the dielectric will break down and arcing will occur between the capacitor plates. When this happens the capacitor becomes a short-circuit and the flow of direct current through it can cause damage to other electronic parts. Each capacitor has a voltage rating (a working voltage) that should not be exceeded.

So therefore it is safe to use the 50V cap,since you were already using a 25V it just means you have a capacitor that can work up to 50V.If it was the other way around id be concerned. hope this helps

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genny

#22972

capacitor voltage rating | 10 January, 2003

It's always safer to use a higher voltage cap than a lower voltage cap. It isn't a fuse...

There is only one case where we dropped the voltage on a cap. We were using a tantalum cap that was rated to 16V, but had been built in the standard packaging for a 10V cap. Extending the voltage range for this package size made it weak in some other areas of its spec - having more failures for leakage current than the larger package 16V. We couldn't easily change the package size layout to a larger size, so we determined we could live with 10V limit in the circuit.

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RDR

#22973

capacitor voltage rating | 10 January, 2003

Thanks Genny, Mantis, Our line is back up and running!

Russ

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#23000

capacitor voltage rating | 14 January, 2003

You may find that the higher volatage rated parts are thicker. Same footpring but "taller". Usually not a problem unless the board is inserted into a mold. BTDT.

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