Question

What is rectifier? Explain with neat circuit diagram the action of semiconductor diode as a full wave rectifier.

Answer 1

Rectifier: A circuit or device that is used to convert an alternating voltage to a direct voltage is called rectifier.
Action of semiconductor diode as a full wave rectifier:
Electric circuit: The alternating voltage to be rectified is applied across primary coil $\left(P_1{P}_2\right)$ of a transformer with a centre tapped secondary coil $\left(S_1{S}_2\right)$. The terminals $S_1,S_2$ of the secondary coil are connected to the two p-regions of two junction diode-$D_1$ and $D_2$ respectively. The centre tap T is connected to the ground. The load resistance $R_L$ is connected across the common n regions and the ground.
Working: During one half cycle of the input, terminal $S_1$ of secondary is positive while $S_2$ is negative with respect to the ground. During the half cycle, diode $D_1$ is forward biased and conducts, while diode $D_2$ is reverse biased and does not conduct. The direction of current $I_L$ through $R_L$ is in the sense shown.
During the next half cycle of the input voltage, $S_2$ becomes positive while $S_1$ is negative with respect to T Diode. $D_2$ now conducts sending a current $I_L$ through $R_L$ in the same sense as before. $D_1$ now does not conduct. Thus, the current through $R_L$ flows in the same direction i.e., It is unidirectional, for both halves of the full-wave of the input. This is called full wave rectification.