Question

In Fig(a) the forward bias ideal diode is D. The applied voltage at anode varies with time as shown in Fig(b). The variation of current in circuit as a function of time is (knee voltage of diode = 0.5 V)

Answer 1

Correct option is (1)

From 0 to 1 ms anode A is at a higher potential than C as time increase. Diode is forward biased. Since knee voltage of diode is 0.5 when applied p.d is less than or equal to 0.05 V there is no current in circuit. The applied p.d is 0.5 V at t = 0.5 ms. Therefore current I in circuit is zero in time interval 0 < to < 0.5 ms.

From 0.5 ms to 1 ms p.d of point increases from 0.5 to 1 V. There is a current in circuit. I_max at t = 1 ms is

In time interval 1 < t < 2 ms anode A is at a lower potential than cathode C. Diode is reverse biased. There is no current in circuit. This pattern repeats itself. The described variation of I with time are shown in (1).