Screening method for electrolytic capacitors

A method of iteratively screening a lot of electrolytic capacitors having a predetermined rated voltage, the method comprising:

• measuring a first leakage current of a first set of capacitors in the lot and calculating a first mean leakage current therefrom;
• removing capacitors from the first set that have a measured first leakage current equal to or above a first predetermined value, thereby forming a second set of capacitors to be subjected to additional testing, the first predetermined value being equal to one or more standard deviations above the first mean leakage current;
• subjecting the second set of capacitors to a burn in treatment, wherein the burn in treatment comprises applying a predetermined test voltage to the capacitors that is from about 0.8 to about 1.2 times the rated voltage;
• after the burn in treatment, measuring a second leakage current of the second set of capacitors and calculating a second mean leakage current therefrom;
• and
• removing capacitors from the second set that have a measured second leakage current equal to or above a second predetermined value, thereby forming a third set of capacitors to be subjected to additional testing, the second predetermined value being equal to one or more standard deviations above the second mean leakage current.