Question

The circuit shown below is working as a $8\text{V}$ DC, regulated voltage source. When $12\text{V}$ is used as input, the power dissipated $\text{in mW}$ in each diode is; (considering both Zener diodes are identical)_______.

Answer 1

Current in the circuit, $I=\frac{V}{R_{eff}}=\frac{12-8}{200+200}={10}^{-2}A$

Potential drop across each diode

$V=\frac{8}{2}=4\text{V}$

Power dissipated in each diode,

$P=VI$

$\Rightarrow P=4\times {10}^{-2}\text{W}=40\text{mW}$