Question

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

Answer 1

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