Q 12-14-145JEE MainJEE Main 2021 (20 Jul, Shift 2)Medium
A zener diode having zener voltage 8 V and power dissipation rating of 0.5 W is connected across a potential divider arranged with maximum potential drop across zener diode is as shown in the diagram. The value of protective resistance $R_p$ is ______ $\Omega$.
Numerical value type. Enter your answer.
Answer: 192
Maximum Zener current: $I = \dfrac{P}{V_z} = \dfrac{0.5}{8} = 62.5$ mA.
With the full 20 V across the series combination:
$$R_p = \frac{20 - 8}{62.5\times10^{-3}} = 192\ \Omega$$
Solution by Sreeraj P, M.Sc Physics