I haven't seen any capacitor with the "Ampere" rating written over its body. Usually they have max. voltage and capacitance ratings, can i know "current" rating from both values?(Supposing AC voltage)
is it simply voltage/reactance ?
Electronic – How to determine the current rating of a capacitor
accapacitorelectrolytic-capacitor
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Best Answer
From the datasheet.
Most capacitors don't actually have a "current" rating, since that doesn't make much sense. You can't put a sustained current thru a capacitor anyway. If you tried, its voltage would rise linearly, and then you'd get to the voltage limit where you'd have to stop. Put another way, current thru a capacitor is inherently AC.
Capacitors do often have a ripple current spec. Capacitors designed to be used in applications where this matters, like switching power supplies, will have a ripple current spec. Check out the Panasonic FK series, for example. These are designed for particularly low ESR (for electrolytic capacitors). Applications where low ESR is important are likely to subject the capacitor to significant ripple current, so this is specified.
Other capacitors are optimized for different purposes where the maximum allowed ripple current isn't relevant, or is so bad the manufacturer doesn't want to admit what it is. In cases where you care, don't use such capacitors.