The polar plot of a transfer function passes through the critical point (-1,0).Gain margin is
A. zero
B. -1dB
C. 1dB
D. Infinity
Answer:A
The polar plot of a transfer function passes through the critical point (-1,0).Gain margin is
A. zero B. -1dB C. 1dB D. Infinity
Explanation: Gain margin is the point where the at phase cross over frequency gain of the system i 1 dB and of a polar plot passing through the critical point is zero.