# Power Electronics (Test 4)

## Gate Exam : Ee Electrical Engineering

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Power Electronics
| Power Electronics |
Q.1
The electron and hole concentrations in an intrinsic semiconductor are ni per cm3 at 300 K. Now, if acceptor impurities are introduced with a concentration of NA per cm3 (where N>> ni , the electron concentration per cm3 at 300 K will be
A. ni
B. ni + NA
C. NA - ni
D. ni/NA
Explaination / Solution:

As per mass action law
np = ni
If acceptor impurities are introduces

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Q.2
In a p n junction diode under reverse biased 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 centre of the depletion region on the n-side
Explaination / Solution:

The electric field has the maximum value at the junction of p n.

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Q.3
The correct full wave rectifier circuit is
A.
B.
C.
D.
Explaination / Solution:

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Topic: Power Electronics Tag:
Q.4
When a bipolar junction transistor is operating in the saturation mode, which one of the following statement is TRUE about the state of its collector-base (CB) and the baseemitter (BE) junctions?
A. The CB junction is forward biased and the BE junction is reverse biased.
B. The CB junction is reversed and the BE junction is forward biased.
C. Both the CB and BE junctions are forward biased.
D. Both the CB and BE junctions are reverse biased.