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One of my power supplies died. Investigation turned out that this capacitor is broken. "102" means 1nF, but does "1 KV" mean 1 kiloVolt or is that some sort of tolerance code?

I've tried several "capacitor code calculators" but none of them mentions "KV" (only K, which is indeed a tolerance code).

enter image description here

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    \$\begingroup\$ What kind of supply is it? \$\endgroup\$ – DKNguyen Jul 6 '19 at 22:05
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Yes, it means 1kV (DC) rating.

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Looks like 1 nF, 1kV capacitor. Tolerance code is usually on the same line as capacitance, for example 102K would be 1nF +-10%.

But to be on the safe side, I would also do an educated guess about the requirements for that capacitor in that application when replacing it. Maybe it has to be of a specific type (desired failure mode in particular) or maybe it is over-specified and operates at much lower voltage.

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Yes, it’s rated for 1000V (1KV), a high voltage rating.

If this cap is part of a safety-critical system (and at that voltage, very likely) review your circuit closely. If there’s line voltage involved, consider using a safety rated X or Y-cap which is designed to fail in a way that will render your circuit safe. X caps go ‘across the line’ and are designed to fail as a short, which should blow the input fuse. Y caps go ‘line to ground’ and are designed to fail open, preventing a shock hazard.

More here: https://www.allaboutcircuits.com/technical-articles/safety-capacitor-class-x-and-class-y-capacitors/

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  • \$\begingroup\$ Actually it's still low voltage. DC HV is >1500V. \$\endgroup\$ – Muhlemmer Jul 7 '19 at 18:10
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    \$\begingroup\$ It depends on how which standard you’re referring. Some say 1000, some say 1500. In the context of the question, a cap with such a high voltage rating is probably dealing with hazardous line voltages and thus needs to be adequate for the task. \$\endgroup\$ – hacktastical Jul 7 '19 at 23:43

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