Question

PN-junction diode works as an insulator, when connected in?
(a) To A.C
(b) In forward bias
(c) In reverse bias
(d) None of these

Answer 1

Hint:PN junction has the quality of transferring current in only one way only. Unlike a resistor, a diode does not work linearly concerning the applied voltage as the diode produces an exponential current-voltage relationship. A diode carries current only when it is forward biased, so there will be a current draw in the circuit, and it offers a vast impedance when reverse biased, so there will be no current draw.

Complete step-by-step solution:
The diode is a two-terminal PN junction that can be utilized in various applications. One such use is an electrical switch. The PN terminal, when forward biased, works as a close circuit, and when reverse biased, works as open-circuited. Hence the variation of forward and reverse biased states performs the diode act as a switch, the forward is ON state and the reverse is OFF state.
In forward biased, $R=0$.
P-N junction gives low resistance when connected in forward biased.
In reverse biased, $R=\mathrm{\infty }$.
P-N junction gives high resistance when connected in reverse biased.
When a p-n junction diode is utilized to prevent the electric current in the occupancy of applied voltage, then the diode is supposed to be a reverse-biased p-n terminal diode.
The n-type semiconductor is joined to the battery's positive terminal, while the p-type semiconductor is combined to the negative terminal of the battery in a reverse-biased p-n junction diode. When the PN junction diode is combined in reverse bias, zero current flows, and operates as an insulator.
Option (c) is correct.

Note: When an n-type semiconductor is combined with the p-type semiconductor, a p-n junction is made. The area where the p-type and n-type semiconductors are combined is called the p-n junction. It is also described as the edge between p-type and n-type semiconductors. This p-n junction makes the most popular semiconductor device known as a diode.