Important questions about Automatic Control Systems. Automatic Control Systems MCQ questions with answers. Automatic Control Systems exam questions and answers for students and interviews.

1. For the transport lag G( j ?) = e -j ?T , the magnitude is always equal to

Options

A : 0

B : 1

C : 10

D : 0.5

2. A negative feedback system has . The closed loop system is stable for

Options

A : K > 20

B : 15 < K < 19

C : 8 ? K ? 14

D : K < 6

4. Stepper motors find applications in

Options

A : X-Y plotters

B : numerically controlled machining equipment

C : printers

D : all of the above

5. The log magnitude curve for a constant gain K is a

Options

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

7. In an integral controller

Options

A : the output is proportional to input

B : the rate of change of output is proportional to input

C : the output is proportional to rate of change of input

D : none of the above

9. Whether a linear system is stable or unstable that it

Options

A : is a property of the system only

B : depends on the input function only

C : both (a) and (b)

D : either (a) or (b)

2. Assertion (A): The steady state response, of a stable, linear, time invariant system, to sinusoidal input depends on initial conditions. Reason (R): Frequency response, in steady state, is obtained by replacing s in the transfer function by j ?

Options

A : Both A and R are correct and R is correct explanation of A

B : Both A and R are correct but R is not correct explanation of A

C : A is correct but R is wrong

D : R is correct but A is wrong

4. A lag compensator is essentially a

Options

A : low pass filter

B : high pass filter

C : band pass filter

D : either (a) or (b)

7. A system has its two poles on the negative real axis and one pair of poles lies on j ? axis. The system is

Options

A : stable

B : unstable

C : limitedly stable

D : either (a) or (c)

8. For type 2 system, the magnitude and phase angle of the term ( j ?) 2 in the denominator, at ? = 0, are respectively

Options

A : 0 and - 90°

B : 0 and + 90°

C : infinity and - 180°

D : infinity and + 180°

9. Bellows converts

Options

A : pressure difference into displacement

B : pressure difference into voltage

C : displacement into pressure difference

D : either (a) or (c)

3. In Bode diagram (log magnitude plot) the factor in the transfer function gives a line having slope

Options

A : -20 dB per octave

B : -10 dB per octave

C : -6 dB per octave

D : -2 dB per octave

8. Bode magnitude plot is drawn between

Options

A : magnitude of network function and ?

B : dB magnitude and log ?

C : dB magnitude and ?

D : log e (magnitude) and log ?

9. If a system is to follow arbitrary inputs accurately the bandwidth should be

Options

A : large

B : small

C : very small

D : neither small nor large

1. A stepper motor is

Options

A : a two phase induction motor

B : is a kind of rotating amplifier

C : is an electromagnetic transducer used to convert an angular position of shaft into electrical signal

D : is an electromechanical device which actuates a train of step angular movements in response to a train of input pulses on one to one basis

2. The phase margin and damping ratio have no relation.

Options

A : True

B : False

C :

D :

9. From the noise point of view, bandwidth should

Options

A : be large

B : not be too large

C : should be as large as possible

D : should be infinite

10. Assertion (A): Potentiometers can not be used as error detectors in position control systems. Reason (R): The resolution of a potentiometer places an upper limit on its accuracy

Options

A : Both A and R are correct and R is correct explanation of A

B : Both A and R are correct but R is not correct explanation of A

C : A is correct but R is wrong

D : R is correct but A is wrong

For the system in the given figure the characteristic equation is

Options

A : a. A

B : b. B

C : c. C

D : d. D

For the system in the given figure. The transfer function C(s)/R(s) is

Options

A : a. G1 + G2 + 1

B : b. G1 G2 + 1

C : c. G1 G2 + G2 + 1

D : d. G1 G2 + G1 + 1

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