Electronics and Experimental Methods-Semiconductor Devices (CSIR Physical Sciences): Questions 4 - 6 of 6

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Question number: 4

» Electronics and Experimental Methods » Semiconductor Devices » Junctions

Appeared in Year: 2014

MCQ▾

Question

A junction is made between a metal of work function WM and a doped semiconductor of work function WS with WM>WS . If the electric field at the interface has to be increased by a factor of 3, then the dopant concentration in the semiconductor would have to be – (December)

Choices

Choice (4) Response
a.

Decreased by a factor of 3

b.

Decreased by a factor of 3

c.

Increased by a factor of 3

d.

Increased by a factor of 9

Question number: 5

» Electronics and Experimental Methods » Semiconductor Devices » Transistors

Appeared in Year: 2012

MCQ▾

Question

The transistor in the given circuit has hfe=35Ω and hie=1000Ω . If the load resistance RL=1000Ω , the voltage and current gain are, respectively – (June)

Circuit diagram of transistor

Circuit Diagram of Transistor

In figure a circuit consist of the transistor is shown.

Choices

Choice (4) Response
a.

+35and35

b.

35and0.97

c.

0.98and35

d.

35and+35

Question number: 6

» Electronics and Experimental Methods » Semiconductor Devices » Diodes

Appeared in Year: 2011

MCQ▾

Question

The figure below shows a voltage regulator utilizing a Zener diode of breakdown voltage 5V and a positive triangular wave input of amplitude 10V.

A circuit for a voltage regulator

A Circuit for a Voltage Regulator

In figure shows a voltage regulator utilizing a Zener diode of breakdown voltage 5V.

Graph of input voltage verses time

Graph of Input Voltage Verses Time

In figure positive triangular wave of voltage passing through Zener diode is shown.

For Vi>5V , the Zener regulates the output voltage by channeling the excess current through itself. Which of the following waveforms shows the current i passing through the Zener diode? (December)

Choices

Choice (4) Response
a.
Current passing through Zener diode: Choice A

Current Passing Through Zener Diode: Choice A

In figure waveforms shows the current passing through Zener diode.

b.
Current passing through Zener diode: Choice B

Current Passing Through Zener Diode: Choice B

In figure waveforms shows the current passing through Zener diode.

c.
Current passing through Zener diode: Choice C

Current Passing Through Zener Diode: Choice C

In figure waveforms shows the current passing through Zener diode.

d.
Current passing through Zener diode: Choice D

Current Passing Through Zener Diode: Choice D

In figure waveforms shows the current passing through Zener diode.

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