Aging Estimation of an AC Adapter from Generated Electromagnetic Noise

Abstract

Capacitors are the parts of a power supply unit that deteriorate most easily. Among types of power supply unit, AC adapters are the ones for which it is not possible to check the leakage or bulging of capacitors, because they are sealed and invisible. Therefore, we focused on the electromagnetic noise which deteriorated AC adapters emit on the power line. We measured their noise and analyzed them with our own method of mode decomposition. It was found that the intensity of the noise is proportional to the internal resistance of the deteriorated capacitors measured in the hot condition.