Question

Draw the circuit diagram of a half-wave rectifier. Hence explain its working. 

Answer 1

Working of half-wave rectifier:

1. The given figure shows the circuit of a half-wave rectifier. 
   
   Half wave rectifier
2. The secondary coil AB of a transformer is connected in series with a diode D and the load resistance R_L. The AC voltage across the secondary coil AB changes its polarities after every half cycle.
3. When the positive half cycle begins, the voltage at point A is at higher potential with respect to that at point B, therefore, the diode (D) is forward biased. It conducts and current flows through the circuit.
4. When the negative half cycle begins, the potential at point A is lower with respect to that at point B and the diode is reverse biased, therefore, it does not conduct and no current passes through the circuit.
5. Hence, the diode conducts only in the positive half cycles of the AC input. It blocks the current during the negative half-cycles. In this way, current always flows through the load R_L in the same direction for alternate positive half cycles and DC output voltage obtained across R_L in the form of alternate pulses.
6. In a half-wave rectifier, the frequency of the ripple in the output is the same as that of the frequency of the input.