Hi everybody, I am curious about how to test film capacitor's life. What are the main parameters that effect a film capacitor's life? Also, are there any circuit designs that you can recommend me to test these parameters or generally the life of the film capacitor? Thanks.
film capacitor life test
May 25, 2009
2 Replies
Commercial film caps have failure rates in the 5 FIT ballpark, where one FIT is one failure per billion hours. So you'd have to run a million caps for thousands of hours to get decent failure rate statistics. The cap manufacturers probably test fewer numbers at high temperature or whatever and apply stress factors to get their FIT estimates.
You can stress a small number of caps to failure, voltage and temperature (and AC current, if it matters) to see what sorts of margins you have.
Decent film caps essentially don't fail if not abused. They seldom fail *if* abused.
John
Temperature and voltage/current are the main parameters, but there are others. This stuff comes down to accelerated testing at extremess and involves statistics and other inferences. It is difficult to understand/implement this type of testing unless you are the manufacturer.
*why* do you want to do this?Dave.
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