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ECE :: Automatic Control Systems

  1. For a stable system having two or more gain crossover frequencies the phase margin is measured at the highest crossover frequency.

  2. A.

     True

    B.

     False


  3. In the field controlled motor the entire damping comes from

  4. A.

     Armature resistance

    B.

     Back emf

    C.

     Motor friction and load

    D.

     Field resistance


  5. In Bode plots the frequency at which two asymptotes meet is called corner frequency.

  6. A.

     True

    B.

     False


  7. Integral control action

  8. A.

     Removes offset

    B.

     May lead to oscillatory response

    C.

     Both (a) and (b)

    D.

     Neither (a) nor (b)


  9. Gain margin and phase margin can be determined from Bode plots as well as Nyquist plot.

  10. A.

     True

    B.

     False


  11. For type 1 system the velocity lag error is

  12. A.

     Inversely proportional to bandwidth of system

    B.

     Directly proportional to gain constant

    C.

     Inversely proportional to gain constant

    D.

     Independent of gain constant


  13. The effect of adding poles and zeros can be determined quickly by

  14. A.

     Nichols chart

    B.

     Nyquist plot

    C.

     Bode plot

    D.

     Root locus


  15. Which of the following can be used as a rotating amplifier in a control system?
    1. Amplidyne
    2. Separately excited dc generator
    3. Synchro
    4. Self excited dc generator

  16. A.

     3 and 4

    B.

     1 and 2

    C.

     1, 2 and 3

    D.

     All


  17. In control systems the output of sensor usually, is

  18. A.

     Analog electrical signal

    B.

     Digital electrical signal

    C.

     Mechanical signal

    D.

     Analog or digital electrical signal


  19. M circles are symmetrical with respect to

  20. A.

     Real and imaginary axis

    B.

     M = 1 straight line and real axis

    C.

     M = 1 straight line and imaginary axis

    D.

     M = 1 straight line