Question

Function of rectifier is
A. To convert ac to dc
B. To convert dc to ac
C. Both (A) and (B)
D. None of these

Answer 1

Hint: To solve this question students must know what a diode is, what PN junction diode is then what a rectifier is. A semiconductor device which is used as a one-way switch is known as diodes. A PN Junction diode is a two layered (PN) device which facilitates the conduction in one direction and stops the conduction in the other direction.

Complete answer:
The PN junction diode has two terminals called electrodes, one from p region and n-region.The p-region acts as Anode (positive terminal) and n region acts as cathode (negative terminal). It has a wide range of applications like rectification (converting AC to DC), Voltage regulation, high voltage protection and wave shaping.

A rectifier is a device which converts A.C voltage to D.C voltage using one or more PN junction diodes. The PN junction diode subjected to an ac voltage acts as a rectifier converting alternating voltage to a pulsating dc voltage.Basically, rectifiers are classified into two categories depending upon the period of conduction.

(a) Half wave Rectifier: The input ac voltage is applied across the rectifier circuit using suitable step-up or step-down transformers. The input voltage to the half wave rectifier circuit is a sinusoidal voltage given by,
$e_s=e_m\sin \omega t$

(b) Full wave Rectifier: The Full wave rectifier conducts during both positive and negative half cycles of A.C input supply. In order to rectify both the half cycles of A.C input, two diodes are used in this circuit. The diodes feed a common load ${\text{R}}_{\text{L}}$ with the help of a transformer.

Therefore, the correct answer is option A.

Note: Students should know the definitions and the concepts of what is diodes, where are diodes used and what a PN junction diode is. Then about the rectifiers, its definition, formulas, application of rectifiers and difference between half wave and full wave rectifiers.