About Control Systems

Following are some of the multiple choice questions on the Control Systems with answers that will help the students in developing their knowledge.

Control Systems MCQ

1. A control system with excessive noise, is likely to suffer from

  • saturation in amplifying stages
  • loss of gain
  • vibrations
  • oscillations

2. For open control system which of the following statements is incorrect ?

  • Less expensive
  • Recalibration is not required for maintaining the required quality of the output
  • Construction is simple and maintenance easy
  • Errors are caused by disturbances

3. Is an open loop control system.

  • Ward Leonard control
  • Field controlled motor
  • Stroboscope
  • Metadyne

4. An automatic toaster is a ______ loop control system.

  • open
  • closed
  • partially closed
  • any of the above

5. Spring constant in force-voltage analogy is analogous to

  • capacitance
  • reciprocal of capacitance
  • current
  • resistance

6. The initial response when tne output is not equal to input is called

  • Transient response
  • Error response
  • Dynamic response
  • Either of the above

7. The transient response, with feedback system,

  • rises slowly
  • rises quickly
  • decays slowly
  • decays quickly

8. Velocity error constant of a system is measured when the input to the system is unit _______ function.

  • parabolic
  • ramp
  • impulse
  • step

9. In open loop system

  • the control action depends on the size of the system
  • the control action depends on system variables
  • the control action depends on the input signal
  • the control action is independent of the output

10. A.C. servomotor is basically a

  • universal motor
  • single phase induction motor
  • two phase induction motor
  • three phase induction motor

11. The transfer function technique is considered as inadequate under which of the following conditions ?

  • Systems having complexities and non-linearities
  • Systems having stability problems
  • Systems having multiple input disturbances
  • All of the above

12. Is the reference input minus the primary feedback.

  • Manipulated variable
  • Zero sequence
  • Actuating signal
  • Primary feedback

13. Pressure error can be measured by which of the following ?

  • Differential bellows and straingauge
  • Selsyn
  • Strain gauge
  • Strain gauge and potentiometer

14. In a stable control system saturation can cause which of the following ?

  • Low-level oscillations
  • High-level oscillations
  • Conditional stability
  • Overdamping

15. Phase margin of a system is used to specify which of the following ?

  • Frequency response
  • Absolute stability
  • Relative stability
  • Time response

16. The transfer function is applicable to which of the following ?

  • Linear and time-in variant systems
  • Linear and time-variant systems
  • Linear systems
  • Non-linear systems
  • E. None of the above

17. In a stable control system backlash can cause which of the following ?

  • Underdamping
  • Overdamping
  • Poor stability at reduced values of open loop gain
  • Low-level oscillations

18. The second derivative input signals modify which of the following ?

  • The time constant of the system
  • Damping of the system
  • The gain of the system
  • The time constant and suppress the oscillations
  • E. None of the above

19. Has tendency to oscillate.

  • Open loop system
  • Closed loop system
  • Both (A) and (B)
  • Neither (A) nor (B)

20. A differentiator is usually not a part of a control system because it

  • reduces damping
  • reduces the gain margin
  • increases input noise
  • increases error

21. Mass, in force-voltage analogy, is analogous to

  • charge
  • current
  • inductance
  • resistance

22. The viscous friction co-efficient, in force-voltage analogy, is analogous to

  • charge
  • resistance
  • reciprocal of inductance
  • reciprocal of conductance
  • E. none of the above

23. The capacitance, in force-current analogy, is analogous to

  • momentum
  • velocity
  • displacement
  • mass

24. A phase lag lead network introduces in the output

  • lag at all frequencies
  • lag at high frequencies and lead at low frequencies
  • lag at low frequencies and lead at high frequencies
  • none of the above

25. Technique is not applicable to nonlinear system ?

  • Nyquist Criterion
  • Quasi linearization
  • Functional analysis
  • Phase-plane representation

26. In a control system the output of the controller is given to

  • Final control element
  • Amplifier
  • Comparator
  • Sensor

27. An amplidyne can give which of the following characteristics ?

  • Constant current
  • Constant voltage
  • Constant current as well as constant voltage
  • Constant current, constant voltage and constant power
  • E. None of the above

28. Transfer function of a system is used to calculate which of the following ?

  • The order of the system
  • The time constant
  • The output for any given input
  • The steady state gain

29. Which of the following is the definition of proportional band of a controller ?

  • The range of air output as measured variable varies from maximum to minimum
  • The range of measured variables from set value
  • The range of measured variables through which the air output changes from maximum to minimum
  • Any of the above
  • E. None of the above

30. Signal will become zero when the feedback signal and reference signs are equal.

  • Input
  • Actuating
  • Feedback
  • Reference

31. Is not a final control element.

  • Control valve
  • Potentiometer
  • Electropneumatic converter
  • Servomotor

32. In closed loop control system, with positive value of feedback gain the overall gain of the system will

  • decrease
  • increase
  • be unaffected
  • any of the above

33. Zero initial condition for a system means

  • input reference signal is zero
  • zero stored energy
  • ne initial movement of moving parts
  • system is at rest and no energy is stored in any of its components

34. By which of the following the system response can be tested better ?

  • Ramp input signal
  • Sinusoidal input signal
  • Unit impulse input signal
  • Exponentially decaying signal

35. Regenerative feedback implies feedback with

  • oscillations
  • step input
  • negative sign
  • positive sign

36. On which of the following factors does the sensitivity of a closed loop system to gain changes and load disturbances depend ?

  • Frequency
  • Loop gain
  • Forward gain
  • All of the above

37. The frequency and time domain are related through which of the following?

  • Laplace Transform and Fourier Integral
  • Laplace Transform
  • Fourier Integral
  • Either (B) or (C)

38. Which of the following can be measured by LVDT?

  • Displacement
  • Velocity
  • Acceleration
  • Any of the above

39. Which of the following is an electromagnetically device ?

  • Induction relay
  • Thermocouple
  • LVDT
  • Any of the above
  • E. None of the above

40. With feedback _____ increases.

  • system stability
  • sensitivity
  • gain
  • effects of disturbing signals

41. Which of the following should be done to make an unstable system stable ?

  • The gain of the system should be decreased
  • The gain of the system should be increased
  • The number of poles to the loop transfer function should be increased
  • The number of zeros to the loop transfer function should be increased

42. The type-2 system has ________ at the origin.

  • No net pole
  • Net pole
  • Simple pole
  • Two poles

43. In a control system integral error compensation _______ steady state error

  • increases
  • minimizes
  • does not have any effect on
  • any of the above

44. By which of the following the control action is determined when a man walks along a path?

  • Brain
  • Hands
  • Legs
  • Eyes

45. Addition of zeros in transfer function causes which of the following?

  • Lead-compensation
  • Lag-compensation
  • Lead-lag compensation
  • None of the above

46. If a step function is applied to the input of a system and the output remains below a certain level for all the time, the system is

  • not necessarily stable
  • stable
  • unstable
  • always unstable
  • E. any of the above

47. Hydraulic torque transmission system is analog of

  • amplidyne set
  • resistance-capacitance parallel circuit
  • motor-generator set
  • any of the above

48. Due to which of the following reasons excessive bond width in control systems should be avoided ?

  • It leads to slow speed of response
  • It leads to low relative stability
  • Noise is proportional to band width
  • None of the above

49. In an open loop control system

  • Output is independent of control input
  • Output is dependent on control input
  • Only system parameters have effect on the control output
  • None of the above

50. The band width, in a feedback amplifier.

  • remains unaffected
  • decreases by the same amount as the gain increase
  • increases by the sane saaaajajt as the gain decrease
  • decreases by the same amount as the gain decrease

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