 # MCQ in Industrial Electronics Part 2 | ECE Board Exam

(Last Updated On: August 8, 2018) This is the Multiples Choice Questions Part 2 of the Series in Industrial Electronics: Principles and Applications as one of the Electronics Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Exam Questions in Electronics Engineering field, Electronics Books, Journals and other Electronics References.

### MCQ Topic Outline included in ECE Board Exam Syllabi

• MCQ in Industrial Electronics
• MCQ in Electronic Control System
• MCQ in Industrial Solid State Services
• MCQ in Welding Systems
• MCQ in Thyristors
• MCQ in High Frequency Heating
• MCQ in Feedback Systems / Servomechanism
• MCQ in Transducers
• MCQ in Motor Speed Control Systems
• MCQ in Robotic Principles
• MCQ in Bioelectrical Principles
• MCQ in Instrumentation and Control

### Continue Practice Exam Test Questions Part 2 of the Series

Choose the letter of the best answer in each questions.

51. What is dimensionless parameter of the second-order characteristic equation?

A. Damping ratio

B. Accuracy

C. Efficiency ratio

D. Transfer function ratio

Solution:

52. What is the ratio of two exponential functions of time called?

A. Transfer function

B. Damping ratio

C. Efficiency

D. Gain

Solution:

53. A diac is turned on by

A. breakover voltage

B. gate current

C. gate voltage

D. anode current

Solution:

54. An SCR whose state is controlled by the light falling upon a silicon semiconductor layer of the device.

A. SCS

B. GTO

C. Thyristor

D. LASCR

Solution:

55. A diac is simply

A. a single junction

B. a three junction device

C. a triac without a gate terminal

D. the SCR

Solution:

56. What region lies between the peak point and valley point of UJT emitter characteristic?

A. Saturation

B. Cut off

C. Negative resistance

D. Positive resistance

Solution:

57. What refers to the application of electronic theory, technology, instrumentation, and computing system to biological research and medical problems?

A. Medical electronics

B. Genetics electronics

C. Biomedical engineering

D. Biomedical electronics

Solution:

58. Which device exhibits negative resistance region?

A. Diac

B. Triac

C. Transistor

D. UJT

Solution:

59. The UJT operates in what region after peak point?

A. Cut off

B. Negative resistance

C. Saturation

D. Positive resistance

Solution:

60. SCR is a rectifier constructed of silicon material. Silicon is chosen because

A. it is the most abundant material

B. of its strength and ruggedness

C. it is much cheaper than any other material

D. of its high temperature and power capabilities

Solution:

61. A transduction principle used primarily in optical sensors.

A. Photoconductive transduction

B. Photovoltaic transduction

C. Electromagnetic transduction

D. Piezoelectric transduction

Solution:

62. What is a solid state equivalent of a gas filled triode?

A. Triac

B. Thyristor

C. SCR

D. SCS

Solution:

63. The supply voltage is generally ________ that of breakover voltage in an SCR.

A. equal to

B. less than

C. greater than

D. twice

Solution:

64. The triac is fundamentally a/an _________ with a gate terminal for controlling the turn-on conditions of the bilateral device in either direction.

A. SCR

C. Shockley diode

D. Diac

Solution:

65. When the supply voltage exceeds the breakover voltage of an SCR, it

A. starts conducting

B. stops conducting

C. conducts leakage current

D. conducts terminal current

Solution:

66. The step response of a first order systems is given by

A. y(t) = A0

B. y(t) = A0 + A1es1t + A2es2t +A3es3t

C. y(t) = A0 + A1es1t + A2es2t

D. y(t) = A0 + A1es1t

Solution:

67. A feedback control system in which the controlled variable is mechanical position.

A. Closed-loop feedback control system

B. Open-loop feedback control system

C. Servomechanism

D. Mechanical servomechanism

Solution:

68. What is that voltage above when the SCR enters the conduction region?

A. Reverse breakover voltage

B. Forward breakover voltage

C. Holding voltage

D. Trigger voltage

Solution:

69. A locus or path of the roots traced out on the s-plane as a parameter is changed.

A. Root locus

B. Hyperbola

C. Parabola

D. Circle

Solution:

70. A control system in which the output is related to the input by device parameters only.

A. Open-loop control system

B. Closed-loop control system

C. Servomechanism

D. Feedback control system

Solution:

71. What is that value of current below which the SCR switches from the conduction state to the forward blocking region under stated conditions?

A. Holding current

B. Forward current

C. Reverse current

D. Trigger current

Solution:

72. Which is equivalent to a zener or avalanche region of the fundamental two-layer semiconductor diode?

A. Reverse breakdown voltage

B. Forward breakdown voltage

C. Breakdown voltage

D. Breakover voltage

Solution:

73. What is the required gate triggering current of GTO?

A. 20 mA

B. 10 mA

C. 30 mA

D. 40 mA

Solution:

74. What is an automatic speed control device using the centrifugal force on rotating flyweights as the feedback element?

A. Regulator

B. Flywheel governor

C. Field control

D. Throttle valve

Solution:

75. What is the sensing element of acceleration transducer?

A. Damper

B. Spring

C. Seismic mass

D. Crystal

Solution:

76. What are some areas where GTO is applicable?

A. Counters

B. Pulse generators

C. Multivibrators

D. All of the above

Solution:

77. What Greek word which means “switch”?

A. Ristor

B. Trans

C. Thy

D. Thyristor

Solution:

78. What is the typical turn-on time of an SCR?

A. 1 μs

B. 5 μs

C. 10 μs

D. 3 μs

Solution:

79. An SCR is a solid state equivalent of which tube?

A. Triode

B. Gas-filled triode

C. Pentode

D. Tetrode

Solution:

80. The gate of an SCR is ________ with respect to its cathode.

A. positive

B. at zero potential

C. negative

D. at infinite potential

Solution:

81. A normally operated SCR has an anode which is ________ with respect to cathode.

A. negative

B. positive

C. at zero potential

D. at infinite potential

Solution:

82. What device measures humidity directly with a single sensing element?

A. Hygrometer

B. Tachometer

C. Venturi meter

D. Hydrometer

Solution:

83. What is one of the most widely used sensing elements particularly for pressure ranges higher than 2 MPa?

A. Bellows

B. Bourdon tube

C. Capsule

D. Straight tube

Solution:

84. Which of the following can change the angle of conduction in SCR?

A. Changing anode voltage

B. Changing gate voltage

C. Reverse biasing the gate

D. Changing cathode voltage

Solution:

85. An SCR is a member of what family?

A. Thyrector

B. Thyratron

C. Thyristor

D. Transistor

Solution:

86. How many pn junction does SCRs have?

A. Two

B. Four

C. Three

D. Five

Solution:

87. Which of the following is NOT a method primarily used for density sensing?

A. Sonic

C. Vibrating element

D. Differential

Solution:

88. When SCR starts conducting, then _________ losses all control.

A. gate

B. anode

C. cathode

D. anode supply

Solution:

89. An SCR when turned on has a typical voltage across of

A. zero

B. 0.1 V

C. infinite

D. 1 V

Solution:

90. The typical turn-off time of an SCR is about

A. 20 to 40 μs

B. 5 to 40 μs

C. 1 to 5 μs

D. 15 to 25 μs

Solution:

91. An SCR is made of what material?

A. Silicon

B. Carbon

C. Germanium

D. Gallium-arsenide

Solution:

92. ECG stands for electrocardiography while EEG stands for?

A. electroextracellugraphy

B. electroemyography

C. electroencephalography

D. electrovectorcardiography

Solution:

93. Acceleration transducers are also called

A. gyros

B. force transducers

C. tachometers

D. accelerometers

Solution:

94. When an SCR is combined to a switch, it is considered as a _______ switch.

A. bidirectional

B. mechanical

C. unidirectional

D. omnidirectional

Solution:

95. When the firing angle of SCR is increased, its output

A. decreases

B. increases

C. remains unchanged

D. doubles

Solution:

96. When the SCR is OFF, the current in the circuit is

A. exactly zero

B. large leakage current

C. small leakage current

D. thermal current

Solution:

97. The SCR can exercise control over ________ of ac supply.

A. positive or negative half-cycle

B. both positive and negative half-cycles

C. only positive half-cycle

D. only negative half-cycle

Solution:

98. What is the most widely used altitude and altitude-rate transducers?

A. Flowmeter

B. Psychometer

C. Gyro

D. Gygrometer

Solution:

99. What sensing element is typically made from a thin-walled tube formed into deep convolutions and sealed at one end, whose displacement can then be made to act on a transduction element?

A. Diaphragm

B. Bellow

C. Capsule

D. Bourdon tube

Solution:

100. The voltage across an SCR when it is turned on is about

A.0.5 V

B. 0.1 V

C. 1 V

D. 5 V

Solution:

### Questions and Answers in Industrial Electronics

Following is the list of multiple choice questions in this brand new series:

MCQ in Industrial Electronics Principles and Applications
PART 1: MCQ from Number 1 – 50                        Answer key: PART 1
PART 2: MCQ from Number 51 – 100                   Answer key: PART 2
PART 3: MCQ from Number 101 – 150                 Answer key: PART 3
PART 4: MCQ from Number 151 – 200                 Answer key: PART 4
PART 5: MCQ from Number 201 – 250                 Answer key: PART 5
PART 6: MCQs from Number 251 – 300                 Answer key: PART 6
PART 7: MCQ from Number 301 – 350                 Answer key: included
PART 8: MCQ from Number 351 – 400                 Answer key: included

### Complete List of MCQs in Electronics Engineering per topic

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