Derating and Category Concepts

The key points to remember from this lesson:

• there are two derating reason: voltage(/current limitation) and temperature
• the derating factors are in “OR“, “whatever is greater” logic relationship, so if the voltage derating rule says 20% and due to the temperature you have to derate 30%, “whatever is greater” condition applies – it means the 30% derating is covering both voltage and temperature derating requirements.

We will have a look into specific capacitor technologies in the second part of this course in more details, nevertheless as a general note here, we can add that almost all major capacitor technologies need a certain derating at their corner specification operating conditions. However, physical reasons for this may be different – reliability, stability of the main electrical parameters or protection against excessive surge current …

Example of capacitor derating chart: