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.Management Sciences
Category: Power Electronics
In EMC signal, the source delivers maximum power to the input of transmission line when the transmission line input impedance
A. Is equal to the source resistance
B. Greater than the source resistance
C. Smaller than the source resistance
D. None of these
The average value of the output voltage in a step – down dc chopper is given by__________?
A. V 0 = V s
B. V 0 = D V s
C. V 0 = V s / D
D. V 0 = V s / ( 1 – D )
SCR will be turned off when anode current is_______________?
A. < latching current but greater than holding current and gate signal is 0.
B. less than holding current.
C. < latching current but greater than holding current and gate signal is present.
D. both (A) and (B).
Example of a voltage clamping device______________?
A. fast acting fuse
B. snubber circuit
C. metal oxide varistor
D. aluminium block
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
Anode current in an SCR consists of____________?
A. holes only
B. electrons only
C. either electron or holes
D. Both electron and holes
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
Anode of an operational SCR is _______________?
A. Always positive w.r.t cathode
B. Always negative w.r.t anode
C. Always positive w.r.t anode
D. Always negative w.r.t cathode
In a full wave rectifier, the rectification ratio is approximately equal to____________?
A. 61%
B. 71%
C. 81%
D. 91%
Practical way of obtaining static voltage equalization in series connected SCRs is by the use of____________?
A. One resistor across the string
B. Resistors of the same value across each SCR
C. Resistors of different values across each SCR
D. One resistor in series with each SCR
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