FILTER CIRCUIT : WHY WE USE ?

• We know that the output of the rectifier is pulsating d.c. ie the output obtained by the rectifier is not pure d.c. but it contains some ac components along with the dc o/p. 
• These ac components are called as Ripples, which are undesirable or unwanted. 
• To minimize the ripples in the rectifier output filter circuits are used. 
• These circuits are normally connected between the rectifier and load as shown below.

• Filter is a circuit which converts pulsating dc output from a rectifier to a steady dc output. In other words, filters are used to reduce the amplitudes of the unwanted ac components in the rectifier.

TYPES OF FILTER

1. Capacitor Filter (C-Filter)

2. Inductor Filter

3. Choke Input Filter (LC-filter)

4. Capacitor Input Filter (Π-filter)