Question

In the given figure, each diode has a forward bias resistance of $30\Omega$ and infinite resistance in reverse bias. The current $I_1$ will be:

• A. 3.75 A
• B. 2.35 A
• C. 2 A
• D. 2.73 A

Answer 1

Answer: (C)

As per diagram,
Diode $D_1\&D_2$ are in forward bias i.e. $R=30\Omega$
whereas diode $D_3$ is in reverse bias i.e. $R=$ infinite
$\Rightarrow$ Equivalent circuit will be
Applying KVL starting from point $A$

$-\left(\frac{I_1}{2}\right)\times 30-\left(\frac{I_1}{2}\right)\times 130-I_1\times 20+200=0$
$\Rightarrow -100I_1+200=0$
$I_1=2$