Explore topic-wise MCQs in Electrical Engineering Questions.

This section includes 217 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.

51.

In a square – wave operation of 3 phase CSIs, the power values are on for___________?
A. 60 degree
B. 90 degree
C. 120 degree
D. 150 degree
Answer» D. 150 degree
Discussion
52.

Ripple factor is the ratio of______________________?
A. Rms value of the ac component of load voltage to the dc voltage
B. Average value of the ac component of load voltage to the peak value of voltage
C. Average value of the dc component of load voltage to the ac voltage
D. Peak value of the dc component of load voltage to the ac voltage
Answer» B. Average value of the ac component of load voltage to the peak value of voltage
Discussion
53.

With gate open, the maximum anode current at which SCR is turned off from ON condition is called____________?
A. breakdown voltage
B. peak reverse voltage
C. holding current
D. latching current
Answer» D. latching current
Discussion
54.

The curve between V and I of SCR when anode is positive w.r.t cathode and when anode is negative w.r.t cathode are known as_____________________?
A. both as forward characteristics
B. both as reverse characteristics
C. former as forward characteristics and later as reverse characteristics
D. former as reverse characteristics and later as forward characteristics
Answer» D. former as reverse characteristics and later as forward characteristics
Discussion
55.

The transfer function of PWM is generally developed in______________?
A. Time domain
B. Frequency domain
C. Either A. or B.
D. None of these
Answer» D. None of these
Discussion
56.

DIAC and TRIAC both are semiconductors devices and conduct in____________________?
A. DIAC conducts in forward direction and TRIAC conducts in reverse direction
B. Both conducts in forward direction
C. Both conducts in reverse direction
D. Both conducts in either direction
Answer» E.
Discussion
57.

In a 3 phase VSI SPWM to use a single carrier signal and preserve the features of PWM technique, the normalized carrier frequency should be____________?
A. Multiple of two
B. Odd multiple of three
C. Odd multiple of five
D. Odd multiple of seven
Answer» C. Odd multiple of five
Discussion
58.

An SCR can be used___________?
A. as static conductor
B. for power control
C. for speed control of dc shunt motor
D. All of these
Answer» E.
Discussion
59.

A crowbar is a circuit which is used to protect a_____________?
A. voltage sensitive load from excessive dc power supply output voltages
B. current sensitive load from excessive dc power supply output voltages
C. voltage sensitive load from excessive ac power supply output voltages
D. current sensitive load from excessive ac power supply output voltages
Answer» B. current sensitive load from excessive dc power supply output voltages
Discussion
60.

Which semiconductor device acts like a diode and two transistor?
A. UJT
B. Diac
C. Triac
D. SCR
Answer» D. SCR
Discussion
61.

Under over voltage condition impedance offered by the voltage clamping device is__________?
A. low
B. High
C. moderate
D. infinity
Answer» B. High
Discussion
62.

The latching current of GTO should be of order
A. 100 mA
B. 500 mA
C. 1 A
D. 2 A
Answer» C. 1 A
Discussion
63.

Example of a voltage clamping device______________?
A. fast acting fuse
B. snubber circuit
C. metal oxide varistor
D. aluminium block
Answer» D. aluminium block
Discussion
64.

The maximum di/dt in a SCR is____________?
A. Directly proportional to supply voltage
B. Directly proportional to inductance in the circuit
C. Inversely proportional to supply voltage
D. Both A and B
Answer» E.
Discussion
65.

Switching frequency of SITH is____________?
A. 5 KHz
B. 10 KHz
C. 60 KHz
D. 100 KHz
Answer» E.
Discussion
66.

The ability of an electronic system to function properly in its intended electromagnetic environment and should not be a source of pollution to that electromagnetic environment is known as____________?
A. Susceptibility
B. Emission
C. Interference
D. Electromagnetic compatibility
Answer» E.
Discussion
67.

In a lossless inverter, the average power absorbed in one period by the load must be__________?
A. Equal to the average power supplied by the dc source
B. Greater than the average power supplied by the dc source
C. Lesser than the average power supplied by the dc source
D. Equal to the average power supplied by the ac source
Answer» B. Greater than the average power supplied by the dc source
Discussion
68.

If all the SCR’s of 3 phase PAC is replaced by diodes, they would be triggered_____________?
A. 120 degree after the zero crossing of the corresponding line voltages
B. 60 degree after the zero crossing of the corresponding line voltages
C. 120 degree before the zero crossing of the corresponding line voltages
D. 60 degree before the zero crossing of the corresponding line voltages
Answer» C. 120 degree before the zero crossing of the corresponding line voltages
Discussion
69.

The opposite of susceptibility is___________?
A. Immunity
B. Emission
C. Interference
D. Electromagnetic compatibility
Answer» B. Emission
Discussion
70.

The phase angle of gate signal in TRIAC can be shifted by using_____________?
A. A capacitor
B. A variable resistor
C. An inductor
D. Only (a) and (b)
Answer» E.
Discussion
71.

The output current in PWM DC – DC converters is equal to___________?
A. Average value of the output inductor current
B. Product of an average inductor current and a function of duty ratio
C. Either A. or B.
D. None of these
Answer» D. None of these
Discussion
72.

A step – down choppers can be used in___________?
A. Electric traction
B. Electric vehicles
C. Machine tools
D. All of these
Answer» E.
Discussion
73.

In a full bridge VSI, in order to avoid the short circuit across the DC bus and the undefined AC output voltage condition, the modulating technique should ensure that___________?
A. Top switch of each leg is on at any instant
B. Bottom switch of each leg is on at any instant
C. Either A. or B.
D. None of these
Answer» D. None of these
Discussion
74.

The ac voltage controller can be used for ___________?
A. Lighting and heating control
B. On – line transformer tap changing
C. Soft starting
D. All of these
Answer» E.
Discussion
75.

A TRIAC can be turned on with______________?
A. Positive voltage at the gate terminal
B. Negative voltage at the gate terminal
C. Either (a) or (b)
D. None of these
Answer» D. None of these
Discussion
76.

In the SPWM, the modulating signal is___________?
A. Square
B. Sinusoidal
C. Triangular
D. Saw – tooth
Answer» C. Triangular
Discussion
77.

Bidirectional semiconductor device is___________?
A. Diode
B. BJT
C. SCR
D. TRIAC
Answer» E.
Discussion
78.

The Graetz bridge makes excellent use of ______________?
A. Current transformer
B. Potential transformer
C. Power transformer
D. SCR
Answer» D. SCR
Discussion
79.

In dual converters________________?
A. Both rectifiers provides positive current to the load
B. Both rectifiers provide negative current to the load
C. One rectifiers provide positive current to the load and the other negative current
D. One rectifier provide positive current to the source and the other negative current to the load
Answer» B. Both rectifiers provide negative current to the load
Discussion
80.

The power MOSFET device is a___________?
A. Current controlled unipolar device
B. Voltage controlled unipolar device
C. Current controlled bipolar device
D. Voltage controlled bipolar device
Answer» C. Current controlled bipolar device
Discussion
81.

Which triggering is the most reliable____________?
A. Forward voltage triggering
B. Gate triggering
C. dV / dt triggering
D. Thermal triggering
Answer» C. dV / dt triggering
Discussion
82.

Which of following devices has highest di/dt and dv/dt capability?
A. SIT
B. SITH
C. GTO
D. SCR
Answer» D. SCR
Discussion
83.

The input current waveform of a bridge controlled rectifier when the load is perfectly filtered is___________?
A. Sine wave
B. Square wave
C. Saw – tooth wave
D. Trapezoidal wave
Answer» C. Saw – tooth wave
Discussion
84.

If the anode current is 800 A, then the amount of current required to turn off the GTO is about____________?
A. 20 A
B. 200 A
C. 600 A
D. 400 A
Answer» C. 600 A
Discussion
85.

A full wave rectifier with resistive load produces___________?
A. Second harmonic
B. Third harmonic
C. Fifth harmonic
D. Do not produce harmonics
Answer» E.
Discussion
86.

Leakage current flows through the thyristor in_________?
A. forward blocking mode
B. reverse blocking mode
C. both forward and reverse blocking mode
D. forward conduction mode
Answer» D. forward conduction mode
Discussion
87.

Which of the following is disadvantage of fast recovery diodes?
A. Recovery is only 5 µs
B. Recovery is only 50 µs
C. Doping is carried out
D. None of these
Answer» D. None of these
Discussion
88.

A power semiconductor may undergo damage due to____________?
A. High di/dt
B. High dv/dt
C. Low di/dt
D. Low dv/dt
Answer» B. High dv/dt
Discussion
89.

A single phase full bridge inverter can operated in load commutation mode in case load consist of______?
A. RL.
B. RLC underdamped
C. RLC overdamped
D. RLC critically damped
Answer» C. RLC overdamped
Discussion
90.

CB used for over current protection of thyristor operates when the fault current is__________?
A. of long period
B. of short duration
C. both (A) and (B)
D. neither (A) nor (B)
Answer» B. of short duration
Discussion
91.

An ideal diode is___________?
A. Unidirectional
B. Bidirectional
C. Fixed voltage polarity
D. Only (a) and (c)
Answer» E.
Discussion
92.

The IGBT resulted in higher switching speed and lower energy losses. It can be used for___________?
A. Uninterruptible power supplies
B. Induction heating system
C. Constant voltage and frequency power supplies
D. All of these
Answer» E.
Discussion
93.

Choppers is a_______________?
A. AC – DC converters
B. AC – AC converters
C. DC – AC converters
D. DC – DC converters
Answer» E.
Discussion
94.

The advantage of using free – wheeling diode in half controlled bridge converter is that
A. There is always a path for the dc current independent of the ac line
B. There is always a path for the ac current independent of the ac line
C. There is always a path for the dc current dependent of the ac line
D. There is always a path for the ac current independent of the ac line
Answer» B. There is always a path for the ac current independent of the ac line
Discussion
95.

The on – state voltage drop of IGBT consists of__________?
A. Drop across the collector junction
B. Drop across the drift region
C. Drop across MOSFET portion
D. All of these
Answer» E.
Discussion
96.

Harmonics in 3 phase inverters can be reduced by using___________?
A. Passive filter
B. Active filter
C. Both passive and active filters
D. None of these
Answer» D. None of these
Discussion
97.

To detect an over – current fault condition, the most reliable method is to connect a_____________?
A. Current sensor across IGBT
B. Voltage sensor across IGBT
C. Current sensor in series with IGBT
D. Voltage sensor in series with IGBT
Answer» D. Voltage sensor in series with IGBT
Discussion
98.

The maximum firing angle in the half wave controlled regulator is_____________?
A. 180 degree
B. 190 degree
C. 200 degree
D. 210 degree
Answer» E.
Discussion
99.

n a phase controlled 3 phase ac voltage controller, the harmonic present is__________?
A. 2nd
B. 3rd
C. 5th
D. 7th
Answer» B. 3rd
Discussion
100.

For bidirectional operation of converters____________?
A. A parallel combination of controllable switch and a diode is used
B. A parallel combination of controllable switch and capacitor is used
C. A series combination of controllable switch and a diode is used
D. A series combination of controllable switch and a capacitor is used
Answer» B. A parallel combination of controllable switch and capacitor is used
Discussion