Circuit diagram CLC or Π filter:
Working : It consist of a filter capacitor C1 connected across the rectifier o/p , a choke L is series and another filter capacitor C2 connected across the load. The pulsating o/p from the rectifier is applied across the i/p terminals 1 & 2 of the filter. The filtering action of the three components C1 C2 and L is described below: The filter capacitor C1 offers low reactance to a.c component of rectifier output while it offers infinite reactance to the d.c. component. Therefore, capacitor C1 bypasses an appreciable amount of a.c component while the d.c component continues its journey to the choke L. The choke L offers high reactance to the a.c component but it offers almost zero reactance to the d.c component. Therefore, it allows the d.c component to flow through it, while the unbypassed a.c component is blocked. The filter capacitor C2 bypasses the a.c component which the choke has failed to block. Therefore, only d.c component appears across the load and that is what we desire.