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Which one of the following statements is correct?

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ESE Electronics 2014 Paper 2: Official Paper
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  1. Phase margin is always positive for a stable feedback system.
  2. Phase margin is always negative for a stable feedback system.
  3. Phase margin can be negative or positive for a stable feedback system.
  4. None of the above

Answer (Detailed Solution Below)

Option 1 : Phase margin is always positive for a stable feedback system.
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Both gain Margin (dB) and phase margin should be positive for a stable feedback system.
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