Early detection of electronic failures

EE 26 May 1986 EARLY DETECTION OF ELECTRONIC FAILURES by N.A. Cole, CEng, MIERE The graphical relationship between the failure rate and operating time of vir- tually any man-made product follows a curve which, because of its shape, is known as a "bath tub". Such a curve has three distinctive regions, the first of which represents an unexpec- tedly high failure rate within the first year of op- eration. The central flat region, ex- tending from about one to ten years, represents nor- mal operating perform- ance where the failure rate is as predicted. The third region represents the so called "wear out" phase where an increas- ingly high failure rate is to be expected as the prod- uct enters its end of useful life period. Failures that occur in the first year of operation fall into three categories: * Failure to function on the very first occasion (dead on arrival). * Failure almost immedi- ately after first use (in- fant mortality). * Failure early in the first year of use (early l...