For the circuit shown in the figure, determine the current through the Zener diode (Given: Zener diode is at break down voltage ${\mathrm{V}}_{\mathrm{z}}=\text{5.6}\mathrm{ }\mathrm{V}$)

• A

  $5\mathrm{mA}$
• B

  $17\mathrm{mA}$
• Correct answer
  C

  $10\mathrm{mA}$
• D

  $7\mathrm{mA}$

Solution

${\mathrm{i}}_1-{\mathrm{i}}_2=\frac{{\mathrm{V}}_{\mathrm{z}}}{800}=\frac{\text{5.6}}{800}=7\mathrm{ }\mathrm{mA}$

For loop $\mathrm{ABCF}$,

$9-200{\mathrm{i}}_1-{\mathrm{V}}_{\mathrm{z}}=0$

${\mathrm{i}}_1=\text{0.017}$ or $17 \mathrm{mA}$

${\mathrm{i}}_2=\left({\mathrm{i}}_1-7\right) \mathrm{mA}$

$=10 \mathrm{mA}$

Hence, the correct answer is option: 'C'.