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ECE :: Automatic Control Systems

  1. A lead compensator is basically a

  2. A.
    high pass filter
    B.
    low pass filter
    C.
    band stop filter
    D.
    none of the above

  3. In Bode diagram (log magnitude plot) of the factor 1/(1 + jωT) in the transfer function the log magnitude for ω << 1/T can be approximated by

  4. A.
    0 dB
    B.
    20 log ωT dB
    C.
    -20 log ωT dB
    D.
    none of the above

  5. Assertion (A): The part of root locus on the real axis is not dependent on the poles and zeros which are not on the real axis.

    Reason (R): Poles and zeros which are not on the real axis occur in conjugate pairs

  6. 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

  7. The phase angle of is constant and equal to - 90° for all values of ω

  8. A.
    True
    B.
    False

  9. For underdamped second order systems the rise time is the time required for the response to rise from

  10. A.
    0% to 100% of its final value
    B.
    10% to 90% of its final value
    C.
    5% to 95% of its final value
    D.
    either (a) or (b)

  11. The open loop frequency response of a unity feed back system is as under

    The gain margin and phase margin respectively are

  12. A.
    20 dB and 15°
    B.
    20 dB and 25°
    C.
    6 dB and 15°
    D.
    6 dB and 25°

  13. 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.

  14. 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

  15. The transfer function can be for

  16. A.
    lead compensator
    B.
    lag compensator
    C.
    either (a) or (b)
    D.
    neither (a) nor (b)

  17. In response to a unit step input the controller output in given figure is for

  18. A.
    proportional controller
    B.
    proportional plus integral controller
    C.
    integral controller
    D.
    none of the above

  19. 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

  20. A.
    synchro control transformer
    B.
    LVDT
    C.
    stepper motor
    D.
    tacho generator