Question

The circuit shown in the figure contains three diodes each with forward resistance of $50\Omega$ and with infinite backward resistance. If the battery voltage is $6V$, the current through the $100\Omega$ resistance is

• A. zero
• B. 36 mA
• C. 43 mA
• D. 50 mA

Answer 1

Answer: (B)

According to the given polarity, diode $D_1$ and $D_2$ are forward biased while $D_3$ is revers biased.
Hence current will pass through $D_1$ and $D_2$ only.
Total restiance in drcuit. $R=\frac{100\times 200}{200+100}+100$
$R=\frac{200}{3}+100=\frac{500}{3}$
$\therefore$ Current, $i=\frac{6}{\frac{500}{3}}=\frac{18}{500}=36\times 10^{-3}$
$=36mA$