Question

In half - wave rectification, what is the output frequency, if the input frequency is $50Hz$? What is the output frequency of a full - wave rectifier for the same input frequency?

Answer 1

Hint: The half wave rectifier conducts current only during the positive half cycles of the input supply voltage. No current is conducted during the negative half cycles and hence no voltage appears across the load. So current always flows in one direction (i.e. d.c.) through the load.

Complete Step by Step Solution:
Half-wave rectifier, in which the sinusoidal output of a function generator passes through a diode and a series resistor. This gives an output voltage that swings positive on the positive-going half-cycle and is zero during the negative-going half-cycle.
The output frequency of a half wave rectifier is equal to the input frequency.
It has been given that, in half - wave rectification, the input frequency is $50Hz$. Thus, output frequency=input frequency= $50Hz$.
For a full-wave rectifier, the output frequency is twice the input frequency. Thus, when input frequency is $50Hz$,

Output frequency of full-wave rectifier is $2 \times 50Hz = 100Hz.$

Note: Rectification is a process which converts AC current to DC current, therefore, we cannot call it a frequency if AC is rectified.
During the positive half cycles of input supply voltage, one end of the rectifier becomes positive with respect to the other end. This makes the diode in the circuit forward biased and hence it conducts current.
During negative half cycles, one end becomes negative with respect to the other end. So the diode is reverse biased and hence conducts no current.
So current flows through the diode only during the positive half cycles of the input a.c. voltage.
After rectification half-wave or full-wave, the output is a Pulsating DC. Normally a Capacitor is connected to make this Pulsating DC into smooth DC.