Question

In the given circuit if breakdown voltage of zener diode is 3 volt, then power of zener diode is:

• A. $0.5W$
• B. $0.12W$
• C. $0.33W$
• D. $0.21W$

Answer 1

The correct option is D $0.21W$

$\begin{array}{c}{V}_z=3V=i_r\times 100\\ i_r=0.03\\ \therefore 2=i\times 20\\ i=0.1A\end{array}$
$\begin{array}{cc}{i}_2& =0.1-0.03\\ P& =VI\text{means}P=3\times (0.1-0.03)\\ & P=0.21W\end{array}$