A Demonstration of Capacitor Ageing

I designed and performed an experiment for a recent class and I'm posting the results here simply for the purpose of record keeping. The stated goal of the experiment was to monitor and analyze the ageing of an electrolytic capacitor. The real purpose of the assignment was to design, build, test, and refine a data collection apparatus for this purpose, as the actual ageing process would take a fairly long time using the equipment available to us. Other experiments in this area were able to "kill" electrolytic capacitors in as little as one week, by charging and discharging them at 100MHz. Our lab did not possess and RF equipment, so this was not achievable for us. For our experiment, we designed and built a charge/discharge/monitoring circuit using a microcontroller that cycled a 0.33μF electrolytic capacitor between 5V and 0V at 100kHz.

Our final report is available here, and results are summarized below.

We designed and built a fairly simple amplifier circuit to cycle our capacitor,

we wrote a stack of LabVIEW programs to control and monitor that circuit,

and we collected data over the course of several weeks.

Data was inline with expectations. Other experiments that cycled at 100MHz saw 1% change after 24 hours. Operating at 100kHz, we would expect 1% change after perhaps three years.