Filter capacitor

Filter capacitors are any capacitors used for filtering. Filter capacitors are common in electrical and electronic work, and cover a number of applications, such as:

Glitch removal on dc power rails
Radio frequency interference (RFI) removal for signal or power lines entering or leaving equipment
Capacitors used after the reservoir capacitor to further smooth dc power supplies
capacitors used in audio, IF or RF frequency filters (eg low pass, high pass, notch, etc)
arc suppression