Ageing Model for Electrolytic Capacitors Under Thermal Overstress

Electrolytic capacitors are widely used components in various applications such as power supplies in avionics, DC–DC converters, and regulation and protection system of a nuclear reactor. These capacitors are frequently responsible for system failures. Ageing of the capacitor, influenced by operating thermal and electrical conditions, leads to failure, indicated by a change in capacitance and equivalent series resistance (ESR) beyond acceptable limits. As part of an experimental programme towards the development of degradation models for electronic components, we have performed accelerated ageing experiments on electrolytic capacitors under thermal overstress. Capacitance and ESR values are recorded with ageing time for various predefined levels of thermal overstress conditions. Based on the experimental results, a degradation model for electrolytic capacitors has been developed. This paper presents a detailed account of the experiments and the degradation model developed.