Quiz  /  Control Systems Electrical Engineering MCQ Interview Questions and Answers PDF

  • 1. 
    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

  • 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. 
    A control system in which the control action is somehow dependent on the output is known as

  • Closed loop system
  • Semiclosed loop system
  • Open system
  • None of the above

  • 4. 
    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

  • 5. 
    Which of the following is an open loop control system ?

  • Field controlled D.C. motor
  • Ward leonard control
  • Metadyne
  • Stroboscope

  • 6. 
    Which of the following statements is not necessarily correct for open control system ?

  • Input command is the sole factor responsible for providing the control action
  • Presence of non-linearities causes malfunctioning
  • Less expensive
  • Generally free from problems of non-linearities

  • 7. 
    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

  • 8. 
    has tendency to oscillate.

  • Open loop system
  • Closed loop system
  • Both (a) and (b)
  • Neither (a) nor (b)

  • 9. 
    A good control system has all the following features except

  • good stability
  • slow response
  • good accuracy
  • sufficient power handling capacity

  • 10. 
    A car is raining at a constant speed of 50 km/h, which of the following is the feedback element for the driver ?

  • Clutch
  • Eyes
  • Needle of the speedometer
  • Steering wheel
  • None of the above

  • 11. 
    The initial response when tne output is not equal to input is called

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

  • 12. 
    A control system working under unknown random actions is called

  • computer control system
  • digital data system
  • stochastic control system
  • adaptive control system

  • 13. 
    An automatic toaster is a ______ loop control system.

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

  • 14. 
    Any externally introduced signal affecting the controlled output is called a

  • feedback
  • stimulus
  • signal
  • gain control

  • 15. 
    A closed loop system is distinguished from open loop system by which of the following ?

  • Servomechanism
  • Feedback
  • Output pattern
  • Input pattern

  • 16. 
    is a part of the human temperature control system.

  • Digestive system
  • Perspiration system
  • Ear
  • Leg movement

  • 17. 
    By which of the following the control action is determined when a man walks along a path ?

  • Brain
  • Hands
  • Legs
  • Eyes

  • 18. 
    Which of the following devices are commonly used as error detectors in instruments ?

  • Vernistats
  • Microsyns
  • Resolvers
  • Any of the above

  • 19. 
    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

  • 20. 
    increases the steady state accuracy.

  • Integrator
  • Differentiator
  • Phase lead compensator
  • Phase lag compensator

  • 21. 
    A.C. servomotor resembles

  • two phase induction motor
  • Three phase induction motor
  • direct current series motor
  • universal motor

  • 22. 
    As a result of introduction of negative feedback which of the following will not decrease ?

  • Band width
  • Overall gain
  • Distortion
  • Instability

  • 23. 
    Regenerative feedback implies feedback with

  • oscillations
  • step input
  • negative sign
  • positive sign

  • 24. 
    The output of a feedback control system must be a function of

  • reference and output
  • reference and input
  • input and feedback signal
  • output and feedback signal

  • 25. 
    is an open loop control system.

  • Ward Leonard control
  • Field controlled D.C. motor
  • Stroboscope
  • Metadyne

  • 26. 
    A control system with excessive noise, is likely to suffer from

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

  • 27. 
    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

  • 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. 
    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

  • 30. 
    On which of the following factors does the sensitivity of a closed loop system to gain changes and oad disturbances depend ?

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

  • 31. 
    The transient response, with feedback system,

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

  • 32. 
    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
  • None of the above

  • 33. 
    Which of the following statements is correct for a system with gain margin close to unity or a phase margin close to zero ?

  • The system is relatively stable
  • The system is highly stable
  • The system is highly oscillatory
  • None of the above

  • 34. 
    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

  • 35. 
    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

  • 36. 
    In an automatic control system which of the following elements is not used ?

  • Error detector
  • Final control element
  • Sensor
  • Oscillator

  • 37. 
    In a control system the output of the controller is given to

  • final control element
  • amplifier
  • comparator
  • sensor
  • none of the above

  • 38. 
    A controller, essentially, is a

  • sensor
  • clipper
  • comparator
  • amplifier

  • 39. 
    The capacitance, in force-current analogy, is analogous to

  • momentum
  • velocity
  • displacement
  • mass

  • 40. 
    The temperature, under thermal and electrical system analogy, is considered analogous to

  • voltage
  • current
  • capacitance
  • charge
  • none of the above

  • 41. 
    In electrical-pneumatic system analogy the current is considered analogous to

  • velocity
  • pressure
  • air flow
  • air flow rate

  • 42. 
    In liquid level and electrical system analogy, voltage is considered analogous to

  • head
  • liquid flow
  • liquid flow rate
  • none of the above

  • 43. 
    The viscous friction co-efficient, in force-voltage analogy, is analogous to

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

  • 44. 
    In force-voltage analogy, velocity is analogous to

  • current
  • charge
  • inductance
  • capacitance

  • 45. 
    In thermal-electrical analogy charge is considered analogous to

  • heat flow
  • reciprocal of heat flow
  • reciprocal of temperature
  • temperature
  • none of the above

  • 46. 
    Mass, in force-voltage analogy, is analogous to

  • charge
  • current
  • inductance
  • resistance

  • 47. 
    The transient response of a system is mainly due to

  • inertia forces
  • internal forces
  • stored energy
  • friction

  • 48. 
    signal will become zero when the feedback signal and reference signs are equal.

  • Input
  • Actuating
  • Feedback
  • Reference

  • 49. 
    A signal other than the reference input that tends to affect the value of controlled variable is known s

  • disturbance
  • command
  • control element
  • reference input

  • 50. 
    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
  • None of the above

  • 51. 
    From which of the following transfer function can be obtained ?

  • Signal flow graph
  • Analogous table
  • Output-input ratio
  • Standard block system
  • None of the above

  • 52. 
    is the reference input minus the primary feedback.

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

  • 53. 
    With feedback _____ increases.

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

  • 54. 
    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

  • 55. 
    In a system low friction co-efficient facilitates

  • reduced velocity lag error
  • increased velocity lag error
  • increased speed of response
  • reduced time constant of the system

  • 56. 
    Spring constant in force-voltage analogy is analogous to

  • capacitance
  • reciprocal of capacitance
  • current
  • resistance

  • 57. 
    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)

  • 58. 
    An increase in gain, in most systems, leads to

  • smaller damping ratio
  • larger damping ratio
  • constant damping ratio
  • none of the above

  • 59. 
    Static error coefficients are used as a measure of the effectiveness of closed loop systems for pecified ________ input signal.

  • acceleration
  • velocity
  • position
  • all of the above

  • 60. 
    A conditionally stable system exhibits poor stability at

  • low frequencies
  • reduced values of open loop gain
  • increased values of open loop gain
  • none of the above

  • 61. 
    The type 0 system has ______ at the origin.

  • no pole
  • net pole
  • simple pole
  • two poles
  • none of the above

  • 62. 
    The type 1 system has ______ at the origin.

  • no pole
  • net pole
  • simple pole
  • two poles

  • 63. 
    The type 2 system has ______ at the origin.

  • no net pole
  • net pole
  • simple pole
  • two poles

  • 64. 
    The position and velocity errors of a type-2 system are

  • constant, constant
  • constant, infinity
  • zero, constant
  • zero, zero

  • 65. 
    Velocity error constant of a system is measured when the input to the system is unit _______ function.

  • parabolic
  • ramp
  • impulse
  • step

  • 66. 
    In case of type-1 system steady state acceleration is

  • unity
  • infinity
  • zero
  • 10

  • 67. 
    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
  • any of the above

  • 68. 
    Which of the following is the best method for determining the stability and transient response ?

  • Root locus
  • Bode plot
  • Nyquist plot
  • None of the above

  • 69. 
    Phase margin of a system is used to specify which of the following ?

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

  • 70. 
    Addition of zeros in transfer function causes which of the following ?

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

  • 71. 
    technique is not applicable to nonlinear system ?

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

  • 72. 
    In order to increase the damping of a badly underdamped system which of following compensators may be used ?

  • Phase-lead
  • Phase-lag
  • Both (a) and (b)
  • Either (a) and (b)
  • None of the above

  • 73. 
    The phase lag produced by transportation relays

  • is independent of frequency
  • is inverseh’proportional to frequency
  • increases linearly with frequency
  • decreases linearly with frequency

  • 74. 
    Which of the following can be measured by the use of a tachogenerator ?

  • Acceleration
  • Speed
  • Speed and acceleration
  • Displacement
  • None of the above

  • 75. 
    is not a final control element.

  • Control valve
  • Potentiometer
  • Electropneumatic converter
  • Servomotor

  • 76. 
    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
  • None of the above

  • 77. 
    In pneumatic control systems the control valve used as final control element converts

  • pressure signal to electric signal
  • pressure signal to position change
  • electric signal to pressure signal
  • position change to pressure signal
  • none of the above

  • 78. 
    Pressure error can be measured by which of the following ?

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

  • 79. 
    Which of the following devices is used for conversion of co-ordinates ?

  • Microsyn
  • Selsyn
  • Synchro-resolver
  • Synchro-transformer

  • 80. 
    The effect of error damping is to

  • provide larger settling lime
  • delay the response
  • reduce steady state error
  • any of the above
  • none of the above

  • 81. 
    technique gives quick transient and stability response

  • Root locus
  • Bode
  • Nyquist
  • Nichols

  • 82. 
    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

  • 83. 
    Which of the following is the non-linearity caused by servomotor ?

  • Static friction
  • Backlash
  • Saturation
  • None of the above

  • 84. 
    can be extended to systems which are time-varying ?

  • Bode-Nyquist stability methods
  • Transfer functions
  • Root locus design
  • State model representatives

  • 85. 
    When the initial conditions of a system are specified to be zero it implies that the system is

  • at rest without any energy stored in it
  • working normally with reference input
  • working normally with zero reference input
  • at rest but stores energy

  • 86. 
    Which of the following is an electromagnetically device ?

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

  • 87. 
    A differentiator is usually not a part of a control system because it

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

  • 88. 
    If the gain of the critical damped system is increased it will behave as

  • oscillatory
  • critically damped
  • overdamped
  • underdamped
  • none of the above

  • 89. 
    In a control system integral error compensation _______ steady state error

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

  • 90. 
    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
  • None of the above

  • 91. 
    . Which of the following can be measured by LVDT?

  • Displacement
  • Velocity
  • Acceleration
  • Any of the above

  • 92. 
    directly converts temperature into voltage.

  • Thermocouple
  • Potentiometer
  • Gear train
  • LVDT
  • None of the above

  • 93. 
    . 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

  • 94. 
    . Which of the following is the output of a thermocouple ?

  • Alternating current
  • Direct current
  • A.C. voltage
  • D.C. voltage
  • None of the above

  • 95. 
    . A.C. servomotor is basically a

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

  • 96. 
    . The first order control system, which is well designed, has a

  • small bandwidth
  • negative time constant
  • large negative transfer function pole
  • none of the above

  • 97. 
    . Which of the following is exhibited by Root locus diagrams ?

  • The poles of the transfer function for a set of parameter values
  • The bandwidth of the system
  • The response of a system to a step input
  • The frequency response of a system
  • None of the above
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