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ECE :: Automatic Control Systems

  1. If then f(t) =

  2. A.
    cos θ0t
    B.
    sin ω0t
    C.
    eat cos ω0t
    D.
    e-at cos ω0t

  3. When time constant T in any factor is varied, the shapes of log magnitude and phase angle curves remain the same.

  4. A.
    True
    B.
    False

  5. Which of the following is not correct for two phase servomotor?

  6. A.
    Rotor diameter is small
    B.
    Applied voltages are seldom balanced
    C.
    Rotor resistance is low
    D.
    Torque speed curve is linear

  7. Given figure shows the magnitude plot for a system. The steady state error for unit step input is

  8. A.
    1/101
    B.
    1/100
    C.
    1/41
    D.
    1/40

  9. DC servomotors are, generally

  10. A.
    permanent magnet dc motors
    B.
    shunt field motors
    C.
    separately excited dc motors
    D.
    none of the above

  11. As the bandwidth increases, the cost of components

  12. A.
    generally decreases
    B.
    generally increases
    C.
    may increase or decrease
    D.
    does not change

  13. If Nyquist plot has a encirclement of (-1 + jo) point, the system is stable if

  14. A.
    there are no poles of G(s) H(s) in right-half plane
    B.
    there is one pole of G(s) H(s) in right-half plane
    C.
    there is no zeros of G(s) H(s) in right-half plane
    D.
    none of the above

  15. A conditionally stable system has

  16. A.
    one phase crossover frequency
    B.
    two phase crossover frequencies
    C.
    two or more phase crossover frequencies
    D.
    one or more phase crossover frequencies

  17. For very low frequencies, log magnitude for the given figure is

  18. A.
    0 dB
    B.
    -3 dB
    C.
    3 dB
    D.
    10 dB

  19. In a pneumatic bellows

  20. A.
    the input surface, output surface and side walls are corrugated
    B.
    the input surface and output surface are flat but the side walls are corrugated
    C.
    the input surface and side walls are flat but the output surface is corrugated
    D.
    the input surface and output surface are corrugated but the side walls are flat