Question

A zener diode is connected across a source voltage of $12V$ such that $6V$ drops across it. If the power drawn by the zener diode is $2.4mW$, then what is the maximum value of series resistance (in $k\Omega$ ) connected in the circuit?

Answer 1

Answer: 15

Power drawn by zener diode, $P=VI$
$\Rightarrow I=\frac{P}{V}$
$=\frac{2.4\times 10^{-3}}{6}=0.4\times 10^{-3}A$
Now, $V=IR$
Across $R_s:0.4\times 10^{-3}\times R_s=6$
$\Rightarrow R_s=15k\Omega$