# Electronics and Communication Engineering - Automatic Control Systems

### Exercise :: Automatic Control Systems - Section 1

26.

Consider the systems with following open loop transfer functions

1. 2. 3. If unity feedback is used, the increasing order of time taken for unit step response to settle is

 A. 1, 2, 3 B. 3, 1, 2 C. 2, 3, 1 D. 3, 2, 1

Explanation: . For the three systems the values of ξωn are 1.8, 2.5 and 2 respectively.

Hence values of T are 0.55, 0.4 and 0.5 respectively.

27.

The phase margin and damping ratio have no relation.

 A. True B. False

Explanation:

They are related.

28.

For the transport lag G(jω) = e-jωT, the magnitude is always equal to

 A. 0 B. 1 C. 10 D. 0.5

Explanation:

Magnitude is 1.

29.

The log magnitude curve for a constant gain K is a

 A. horizontal straight line B. horizontal straight line of magnitude 20 log K decibels C. an inclined line having slope K D. an inclined line having slope -K

Explanation:

The factor K in the numerator of G(jω) gives is straight line at 20 log10 K in Bode plot.

30.

The compensator of the given figure is a A. lag compensator B. lead compensator C. lag-lead compensator D. none of the above