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Electronics and Communication Engineering - Automatic Control Systems

Exercise : Automatic Control Systems - Section 4
16.
The open loop frequency response of a unity feed back system is as under

The gain margin and phase margin respectively are
20 dB and 15°
20 dB and 25°
6 dB and 15°
6 dB and 25°
Answer: Option
Explanation:
No answer description is available. Let's discuss.
17.

Assertion (A): A large negative feedback is deliberately introduced in an amplifier to make its gain independent of variation in parameters of active device.

Reason (R): A large negative value of feedback results in a high value of return difference compared to unity which makes the feedback gain inversely proportional to the feedback factor.

Both A and R are correct and R is correct explanation of A
Both A and R are correct but R is not correct explanation of A
A is correct but R is wrong
R is correct but A is wrong
Answer: Option
Explanation:

Gain with feedback = .

18.
The transfer function can be for
lead compensator
lag compensator
either (a) or (b)
neither (a) nor (b)
Answer: Option
Explanation:

For a lead compensator and a < 1

Therefore is more than .

19.
In response to a unit step input the controller output in given figure is for
proportional controller
proportional plus integral controller
integral controller
none of the above
Answer: Option
Explanation:

The intercept on y-axis is due to proportional action and inclined line is due to integral action.

20.
An electromechanical device which actuates a train of step angular movements in response to a train of input pulses on one to one basis is
synchro control transformer
LVDT
stepper motor
tacho generator
Answer: Option
Explanation:
No answer description is available. Let's discuss.
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