Question

Consider the following statements:

(a) The effect of feedback is to reduce the system error

(b) Feedback increases the gain of the system in one frequency range but decreases in the other

(c) Feedback can cause a system originally stable to become unstable

(d) Both a and c

The question was asked in a job interview.

This question is from Stability Analysis topic in section Digital Control Systems of Control Systems

Answer 1

Correct answer is (d) Both a and c

The best I can explain: Feedback reduces error and can cause stable system to become unstable and also can make unstable system stable.