Question

What is rectification? Explain the working of a full-wave rectifier with a diagram. What is a zener diode? How will a zener diode be connected in a circuit generally?

Answer 1

Rectification is the process of converting alternating current (AC) which reverses its direction periodically to direct current (DC) which flows only in one direction.
Working:-
Here the configuration used to rectify is of centre tap type and the concept used is that diodes operates only in forward biased, that is, in reverse biased a diode is switched off.
The input waveform is AC, that is, it changes its polarity periodically. In the first half cycle, the diode D1 is in forward biased and is On so it behaves as a short circuit where as the diode D2 is in reverse biased and is Off so it behaves as as an open circuit. The current in the circuit follows the path A-D1-C-R-O-A.
In the second half cycle of the i/p waveform, the polarities change and the diode D1 is in reverse biased and is Off thus behaving as an open circuit where as the diode D2 is in forward biased and is On thus behaving as a short circuit. The current in the circuit follows the path B-D2-C-R-O-B.
The direction of current through the load resistor R does not change that is it flows in downward direction in both the cycles.
Zener diode- It is a diode made up of highly doped p-n junctions which allows the current to flow through it even in reverse biased mode unlike other diodes.
A zener diode is generally connected in reverse biased mode in a circuit for controlling purposes.