What is a rectifier ? With suitable circuit describe the action of a full wave rectifier by drawing input and output waveforms.

Explanation

Fullwave rectification: The process in which both the halves of a.c. are rectified to obtain a pulsating direct current is known as full wave rectification.
A transformer with a centre tap is used for a full wave rectification. Input contains ac. A minimum of two diodes are used at the secondary of the transformer. A load resistor is connected between the junction of the N type semiconductor and the centre tap.

During the first half cycle , diode `D_1` will be forward biased and `D_2` will be reverse biased so that the current flows from B to centre tap.
During the second half cycle, diode `D_2` will be forward biased while `D_1` will be reverse biased. The current once again takes the same direction from B to centre tap . The I/P and the O/P waveforms are shown in fig. The average DC is `2(V_p/pi)`.