Friday, October 12, 2012

Power Semiconductors Solved Objective Questions: Part-I

[1] Which of the following statements are correct?
1. Thyristor is current driven device
2. GTO is current driven device
3. GTR is current driven device
4. SCR is a pulse triggered device
(a) 1 and 2
(b)1, 2, 3
(c) All
(d) 4 only

[2] Which of the following statements are correct?


1.  GTO is a pulse triggered device
2.  MOSFET is uni-polar device
3.  SCR is a bipolar device
4.  Continuous gate signal is not required to maintain the SCR to be in ON state
(a)  1, 2, 4 only
(b)  1, 2 only
(c)  4 only
(d)  All


[3] Which of the following is not a fully controlled semiconductor device?
(a) MOSFET
(b) IGBT
(c) IGCT
(d) SCR

[4] Which of the following is not associated with p-n junction
(a) Junction capacitance
(b) Charge storage capacitance
(c) Depletion capacitance
(d) Channel length modulation


[5] In a p-n junction diode under reverse bias, the magnitude of electric field is maximum at

(a) The edge of the depletion region on the P-side
(b) The edge of the depletion region on the N-side
(c) The P-N junction
(d) The center of the depletion region on the N-side


[6] An n-channel JFET has IDSS=2mA, and Vp=-4V. Its transconductance gm=(in mA/V) for an applied gate to source voltage VGS=-2V is
(a) 0.25
(b) 0.5
(c) 0.75
(d)  1


[7] The MOSFET switch in its on-state may be considered equivalent to
(a) Resistor
(b) Inductor
(c) Capacitor
(d) Battery


[8] The effective channel length of a MOSFET in a saturation decreases with increase in

(a) Gate voltage
(b) Drain voltage
(c) Source voltage
(d) Body voltage


[9] The early effect in a bipolar junction transistor is caused by

(a) Fast turn - on
(b) Fast turn - off
(c) Large collector - base reverse bias
(d) Large emmiter - base forward bias


[10] MOSFET can be used as a

(a) Current controlled capacitor
(b) Voltage controlled capacitor
(c) Current controlled inductor
(d) Voltage controlled inductors


[11] The number of PN junctions in a SCR is
(a) 1
(b) 2
(c) 3
(d) 4


[12] In the SCR, when the anode terminal is positive with respect to cathode terminal, the number of blocked PN junctions is

(a) 1
(b) 2
(c) 3
(d) 4


[13] In the SCR, when the cathode terminal is positive with respect to anode terminal, the number of blocked PN junctions is

(a) 1
(b) 2
(c) 3
(d) 4


[14] In the SCR, the anode current is made up of

(a) Electrons only
(b) Electrons or holes
(c) Electrons and holes
(d) Holes only


[15] When the SCR is triggered, it will change from forward blocking state to conduction state if its anode to cathode voltage is equal to 

(a) Peak repetitive off-state forward voltage
(b) Peak working off-state forward voltage
(c) Peak working off-state reverse voltage
(d) Peak non-repetitive off-state forward voltage



Thanks for reading...
4:26 AM

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