Time Response of Reactive Circuits - Engineering

Q1:

Referring to the above figure, determine the voltage level that the output will reach during the pulse.

A 0 V

B 15 V

C 6.3 V

D 9.45 V

ANS:D - 9.45 V

Here L1=750mH, R1= 680Kohm.
Time constant (T) in LR circuit is L/R = 750 * 10^-3 / 750 * 10^3,
T =1.10 * 10^-6 (1.10 micro Sec).

Time duration of pulse is t =1/1Khz,
t = 1 / 1000 Hz,
t = 1 * 10^-3,
t = 1 milli Sec.

V = Vo ( 1 - e^(-t/T)).
V = 15 ( 1 - e^(- 1* 10^-3 / 1 * 10^3)).
V = 15 ( 1 - e^(- 1* 10^-6)).
V = 15 ( 1 - 0) AS e^(- 1* 10^-6) = nearly zero.
V = 15.
SO, the answer should be B.