Electronics and Communication Engineering - Exam Questions Papers - Discussion

Discussion Forum : Exam Questions Papers - Exam Paper 2 (Q.No. 30)
30.
A certain system has transfer function a is a parameter. Consider the standard negative unity feedback configuration as shown below.

Which of the following statements is true?
The closed loop system in never stable for any value of a a
For some positive values of a, the closed loop system is stable, but not for all positive values
For all positive values of a, the closed loop system is stable
The closed loop system is stable for all values of a, both positive and negative
Answer: Option
Explanation:

Closed loop system transfer function

Use Routh criteria

Thus for all positive value of 'a' this will be stable.

Discussion:
3 comments Page 1 of 1.

Deva said:   8 years ago
Why 2+1?

Praveen said:   8 years ago
That's alpha. Not 2.

Praveen bh said:   8 years ago
For any positive value of alpha. Right. He placed 2 for alpha in the RC. That's it, You can substitute 3, 4, up to infinite values.

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