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

Hint- Rectification is the process in which the alternating current (AC) is converted into direct current (DC). Then, draw the circuit diagram of the full-wave rectifier to explain its working. Similarly, explain about Zener diodes also.

Complete step-by-step answer:

First, we will discuss rectification-

Rectification –
Rectification is the process of converting alternating current (AC) into direct current (DC).
AC current reverses its direction in a regular interval of times or we can say periodically whereas DC current is the current which does not reverse its direction and flows only in one direction.

Circuit Diagram of Full-Wave Rectifier –

Working of a full-wave rectifier –

The above circuit diagram shows the configuration of a full wave rectifier. Here, the configuration which is used to rectify is of centre tap and the concept used is the diodes operate only when forward biased, that is, in reverse biased a diode will be switched off and will not work.

For a rectifier, the input waveform is of AC type, that is, the current which changes its direction periodically. Now, in the first half cycle, the diode D1 is in forward biased and therefore, it is ON, so it behaves as a short circuit whereas the other diode D2 is reverse biased and is OFF, so it behaves as an open circuit.

The path of the current in the circuit is as follows, A – D1 – C – R – O – A.
Now, in the second half cycle of the AC input waveform, the polarities changes and the diode D! which was forward biased in the first half cycle, will be reverse biased in the second half cycle and will be OFF and behave as an open circuit and the diode D2 will be forward biased and will be ON and behave as a short circuit.

The path of the current in this cycle is as follows, B – D2 – C – R – O – B.
Also, the direction of current through the load resistor R does not change i.e., it flows in downward direction in both the cycles.

So, this is the working of the full-wave rectifier. While using the full-wave rectifier, the full -wave gets rectified and in output also we obtain a full DC wave.

Now, it is also asked about Zener diodes in the question, so let us discuss Zener diodes.
Zener Diode –

A Zener diode is a diode which is commonly used as a voltage regulator. It is a special type of diode which can handle breakdown due to reverse breakdown voltage without failing completely. It operates in reverse biased mode to regulate the voltage in a circuit.

Zener diodes are generally connected in the reverse biased mode in a circuit for the controlling purposes.

Note – Whenever such types of questions appear, then always first explain about the process and then write about its working. As mentioned in the solution, about the rectification process, i.e., an AC input is converted into DC output. Also, the terms AC and DC should be very clear in your minds. Also, it should be clear which mode diodes are ON or OFF. After this, we have also explained about Zener diodes and how it is connected in any circuit.