Q 12-14-162JEE MainJEE Main 2021 (27 Aug, Shift 2)Medium
A zener diode of power rating $2$ W is to be used as a voltage regulator. If the zener diode has a breakdown of $10$ V and it has to regulate voltage fluctuated between $6$ V and $14$ V, the value of $R_s$ for safe operation should be ______ $\Omega$.
Numerical value type. Enter your answer.
Answer: 20
Maximum safe zener current: $I_{max} = \dfrac{P}{V_z} = \dfrac{2}{10} = 0.2$ A.
The largest current flows at the highest input, $14$ V (taking no load current):
$$R_s = \frac{14 - 10}{0.2} = 20\ \Omega$$
Solution by Sreeraj P, M.Sc Physics