Question

Consider the circuit shown below, switch is closed at t= 0 sec. When two diodes are ideal, voltage across the capacitor at t-=200 msec is ______ Volts.
(Initial voltage of capacitor $V_c\left(0^{-}\right)=0$)

• A. 0

Answer 1

The correct option is A 0
In positive half cycle,

$\tau =RC=\left(6||3\right)\times 5mF=10msec$

Let, $V_C(t=10msec)=V_0$

In negative half cycle,

$\tau =RC=\left(6||3\right)\times 5mF=10msec$

As time constant in both +ve and -ve cycle are equal , capacitor discharged to zero in -ve half cycle. Voltage across the capacitor after one cycle $(\frac{1}{50}=20msec)$ is zero

$\therefore$ Voltage across the capacitor after 10 cycles (200 msec) is also zero.

$\therefore V_C(t=200msec)=0$