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

Options

A. 0
B. 36 mA
C. 43 mA
D. 50 mA

Answer

B

Explanation

In the given circuit, the upper two diodes `D_(1) and D_(2)` are forward biased and the lower diode `D_(3)` is reverse biased. Hence no diode `D_(3)` The equivalent circuit is as shwon in the figure.

As diode `D_(1)` and `150 Omega` resistor are in series and their combination is in parallel with the series combination of diode `D_(2) and 50Omega` resistor. Theri equivalent resistance is
`(1)/(R.)=(1)/(r_(f)+150Omega)+(1)/(r_(f)+50Omega)=(1)/(50Omega+150Omega)+(1)/(50Omega+50Omega)`
`(1)/(R.)=(1)/(200Omega)+(1)/(100Omega) rArr R.=(200)/(3)Omega`
Total resitance of the circuti, `R=100Omega+(200)/(3)Omega=(500)/(3)Omega`
Current in the circuit,
`I=(V)/(R )=(6V)/((500)/(3)Omega)=3.6xx10^(-2)A=36mA`