Q.Draw the circuit diagram of a half wave rectifier and explain its working

A half wave rectifier uses a transformer, a single p-n junction diode and a load resistor $R_L$ to convert AC into a pulsating DC. During the half-cycle that forward biases the diode, it conducts and current flows through $R_L$, reproducing that half of the input at the output; during the opposite half-cycle the diode is reverse biased, blocks almost entirely, and the output stays at zero -- since only ONE of the two half cycles ever reaches the load, this is a half wave rectifier (reversing the diode passes the other half instead). The result is a series of one-directional pulses with gaps between them, not a steady DC voltage, so it needs further filtering/regulation before powering real electronics; its efficiency (ratio of output DC power to input AC power) is 40.6%, exactly half the full wave rectifier's.