# Electronics and Communication Engineering - Automatic Control Systems

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

11.

For the given figure C(s)/R(s) A. B. C. D. Explanation: .

12.

A stepper motor is

 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

Explanation:

When input pulses are applied, the motor moves in steps.

13.

In a two phase ac servomotor rotor resistance is R and rotor reactance is X. The speed curve will be linear if

 A. B. C. D. X2 = R

Explanation:

In a two phase servomotor ∠ < 1 so that torque speed curve is almost linear.

14.

In the given figure, the input frequency is such that R = XC. Then A. v0 lags vi by 45° B. v0 lags vi by 90° C. v0 leads vi by 45° D. v0 leads vi by 90°

Explanation:

R = XC, voltage drops across R and XC are equal and at 90° with respect by each other. V0 lags Vi by 45°.

15.

From the noise point of view, bandwidth should

 A. be large B. not be too large C. should be as large as possible D. should be infinite