Question

Consider the following statements $\left(\text{A}\right)$ and $\left(\text{B}\right)$ and identify the correct answer.

$\left(\text{A}\right)$ A zener diode is connected in reverse bias, when used as a voltage regulator.

$\left(\text{B}\right)$ The potential barrier of $p-n$ junction lies between $0.1\text{V}$ to $0.3\text{V}.$

• A. $\left(\text{A}\right)$ is incorrect but $\left(\text{B}\right)$ is correct.
• B. $\left(\text{A}\right)$ and $\left(\text{B}\right)$ both are correct.
• C. $\left(\text{A}\right)$ and $\left(\text{B}\right)$ both are incorrect
• D. $\left(\text{A}\right)$ is correct and $\left(\text{B}\right)$ is incorrect.

Answer 1

Answer: (D)

$\bullet$ In reverse biased, after breakdown, voltage across the zener diode becomes constant. Therefore, zener diode is connected in reverse biased when used as voltage regulator.
$\bullet$ Potential barrier of silicon diode is nearly $0.7\text{V}$.
Thus, statement $\left(\text{A}\right)$ is correct and statement $\left(\text{B}\right)$ is incorrect.