Question

A Zener diode
(A) Has a high forward voltage rating
(B) Has a sharp breakdown at low reverse voltage
(C) Has a negative resistance
(D) None of the above

Answer 1

Hint A Zener diode is a special type of diode made to constantly allow current to flow backward (in reverse biased condition) when a certain value of reverse voltage is reached which is also known as the Zener voltage. The breakdown voltage is the minimum reverse voltage that makes the diode conduct appreciably in reverse biased condition.

Complete Step-by-step solution
On applying a negative potential difference to the positive terminal of the Zener diode and positive potential to the negative terminal of the Zener diode this is known as the reverse bias condition of the Zener diode. For a Zener diode, the reverse bias breakdown occurs at low voltage and for the Zener diode, the voltage-current graph is sharp near the breakdown voltage.
Also, the negative resistance of the Zener diode is only in the range of the avalanche breakdown region. But the Zener diode has a positive resistance. We can say this as if we increase current, the voltage developed will increase.

Hence the correct answer to our question is (B) has a sharp breakdown at a low reverse voltage

Additional information
The depletion region is a region inside the semiconductor device, usually at the junction of P-type and N-type semiconductors, in which there is neither an excess of electrons nor of holes. Large depletion regions inhibit current flow through a diode.

Note
The depletion area extends under a very high voltage, and the potential barrier increases, resulting in a very high electric field in the junction. This is known as the Zener effect. The breakdown occurs at reverse voltage, called the breakdown voltage, at a particular and constant value.