Question

State the Need for filters in rectifier

Answer 1

We know that rectifiers are used to convert AC to DC, but not a pure DC. There would be considerable AC component in their output, called ‘ripple’, in addition to the desired d.c. component.

Most sophisticated electronic systems need pure DC supply to drive, or power them. To construct a good power supply which gives pure DC output, we need to remove or filter out the AC component from the output of rectifiers.

The output from these rectifiers with Ripple components, is fed to filter circuits so that the output from the filter is pure DC.

Fig : AC to DC

Most commonly used filter types are:

Capacitor filter

Series inductor filter

Choke input filter

π-filter

RC filter.