A rectifier is actually required to produce pure d.c. supply for using at various places in the electronics circuits. However, the output of a rectifier is pulsating. That means it contains both a.c.component and d.c. component. If such a pulsating d.c. is applied in an electronics circuit, it will produce a hum. So the a.c. component in the pulsating rectifier output is undesirable and must be kept away from the load. To do so, a filter circuit is used which removes the a.c. component and allows only the d.c. component .
A filter circuit is a device which removes the a.c. component of rectifier output and allows only d.c. component to reach the load.
A filter circuit is installed between the rectifier and the load.
