Question

Draw the circuit diagram of a full wave rectifier using two p-n junction diodes and explain its working. Show the input and output waveforms.

Answer 1

Working:- The AC input voltage across secondary $s_1$ and $s_2$ changes polarity after each half cycle. Suppose during the first half cycle of input AC signal, the terminal $s_1$ is positive relative to centre tap O and $s_2$ is negative relative to O. then diode $D_1$ is forward bias and diode $D_2$ is reverse biased. Therefore diode $D_1$ conduct while diode $D_2$ does not.

In next half cycle,

the terminal $s_1$ is negative relative to centre tap O and $s_2$ is positive relative to O. then diode $D_2$ is forward bias and diode $D_1$ is reverse biased. Therefore diode $D_2$ conduct while diode $D_1$ does not.

The direction of current in resistance $R_L$ is same from A to B for both half cycles. hence for input AC signal the output current is a continuous series of unidirectional pulses.