Roughly what latching current should a GTO have?
Correct answer A. 500 mA
Subject / 245 questions
Electrical Engineering MCQs
Page 11 of Electrical Engineering multiple-choice questions with answers. Tap an option to check yourself.
Page 11 of 13
The maximum di/dt in an SCR circuit has what relationship?
Correct answer A. Directly proportional to supply voltage
Which of these is an example of a voltage clamping device?
Correct answer D. Metal oxide varistor
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What is the switching frequency of a SITH (static induction thyristor)?
Correct answer D. 100 kHz
In practice, how is static voltage sharing achieved between SCRs connected in series?
Correct answer B. Resistors of the same value across each SCR
A thyristor can be protected from overvoltages by using a:
Correct answer A. voltage clamping device
A single-phase full bridge inverter can work in load commutation mode when its load is of which type?
Correct answer B. RLC underdamped
What does a snubber circuit connected across an SCR do?
Correct answer A. Suppress dV/dt
An SCR’s gate–cathode characteristic is a straight line with a slope of 130 (Vg/Ig = 130 Ω). With a trigger source of 15 V and an allowable gate power dissipation of 0.5 W, what gate source resistance is required?
Correct answer B. 111.9 Ω
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What is the state of the junctions when a thyristor is in forward blocking mode?
Correct answer A. Junction J2 is reverse biased and J1, J3 are forward biased
What is the state of the junctions when a thyristor is in reverse blocking mode?
Correct answer B. Junctions J1, J3 are reverse biased and J2 is forward biased
A thyristor has a holding current of 2 mA. What would its latching current typically be?
Correct answer B. 0.004 A
Which statement about latching current is correct?
Correct answer C. It is related to the turn-on process of the device
A step-up chopper converts an input of 110 V into an output of 150 V. What is its duty cycle?
Correct answer D. 0.27
A single-phase one-pulse controlled circuit supplies a load of resistance R and counter emf E from a source of 400 sin(314t) V. If the counter emf is 200 V, over what range can the firing angle be controlled?
Correct answer D. 30° to 150°
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Which type of load allows a single-phase full bridge inverter to work in load commutation mode?
Correct answer A. RLC underdamped
Why is an SCR described as a semi-controlled device?
Correct answer B. It can be turned ON but not OFF with a gate pulse
What is the typical short circuit ratio (SCR) of a modern alternator?
Correct answer C. 0.5
An SCR has a half-cycle surge current rating of 3000 A on a 50 Hz supply. What is its one-cycle surge current rating?
Correct answer C. 2121.32 A
What are the three terminals of a TRIAC?
Correct answer A. Two main terminals and a gate terminal