captainbeefheart Posted January 18, 2022 Share Posted January 18, 2022 2 hours ago, Crankysoldermeister said: Shouldn’t clearing happen regardless of voltage rating since it’s due to defects in the film. Defects are one possible 'fault' mode, whatever defect in the film will be cleared during first use. Those small defect areas are more or less a short, this short current vaporizes the metal film causing a void and clearing the short. Other fault modes include over voltage conditions usually from short duration transients. This high potential over voltage causes a corona discharge effect or 'arc' like we discussed before, this arc current will vaporize the metal film creating a void again clearing the problem area. Over current and heat can also damage the capacitor. Every single time there is a fault and the metal film vaporizes making a void and clearing the problem area it effectively continues to reduce the surface area which subsequently lowers the capacitance/reactance which mathematically directly correlates to an increase in ESR. It makes sense if you think about it, you are effectively slowly reducing the overall surface area which directly relates to the amount of capacitance/reactance. From what I gathered the vast majority of faults over the lifetime of a capacitor is from over voltage transients. Small defects in the dielectric are present from manufacturing mostly and clear when used, it will rarely encounter that issue again in it's service life. 2 Quote Link to comment Share on other sites More sharing options...
Deang Posted January 18, 2022 Share Posted January 18, 2022 Thanks. Crazy stuff. 1 Quote Link to comment Share on other sites More sharing options...
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