Capacitance Drift in Capacitors

Capacitance Drift refers to the change in capacitance values over a period of time.  The value of a capacitor will change over the years.  This is because the property of the dielectric material and its ability to polarize or hold charge changes.  This is due to reasons such as age and temperature.  

A normal drift will be around 20% of the capacitance values.  The capacitance value can increase or decrease due to the capacitance drift.    If the capacitor is subject to temperatures beyond its working range or to temperature fluctuations, the value will drift.

The capacitance drift is irreversible.  Hence, capacitors should be selected keeping the capacitance drift in mind.