Q 12-14-153JEE MainJEE Main 2021 (26 Feb, Shift 2)Medium
The zener diode has a $V_z = 30$ V. The current passing through the diode for the following circuit is ______ mA.
Numerical value type. Enter your answer.
Answer: 9
Without the zener, the voltage across $5\ \text{k}\Omega$ would be $90\times\dfrac{5}{9} = 50$ V $> 30$ V, so the zener breaks down and holds $30$ V across the load.
Current through $4\ \text{k}\Omega$: $\dfrac{90 - 30}{4000} = 15$ mA.
Current through $5\ \text{k}\Omega$: $\dfrac{30}{5000} = 6$ mA.
Zener current $= 15 - 6 = 9$ mA.
Solution by Sreeraj P, M.Sc Physics