Question:
The zener diode has a $V_{s}=30 \mathrm{~V}$. The current passing through the diode for the following ciruit is $\mathrm{mA}$
Solution:
$I=\frac{90-30}{4}=15 \mathrm{~mA}$
$\mathrm{I}_{\mathrm{I}}=\frac{30}{5 \mathrm{~K} \Omega}=6 \mathrm{~mA}$
$\mathrm{I}_{2}=15 \mathrm{~mA}-6 \mathrm{~mA}=9 \mathrm{~mA}$