Question

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

Hint:

Always analyze the polar plot at the critical point to determine the system's gain margin and potential for instability.

Answer 1

The Correct Option is A

In control theory, the gain margin is the amount by which the gain can be increased before the system becomes unstable. If the polar plot passes through the critical point (+1,0), the gain margin is considered to be zero, indicating that the system is on the verge of instability.