Diode Circuits MCQs

Question 1

A phototube is an electronic tube

Accepted Answer

that emits photoelectrons when its cathode is illuminated

Answer

that is used in TV sets for producing picture on the screen

Answer

whose resistance decreases as its cathode is exposed to more light

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whichis used for producing a brilliant flash of light for taking photographs in the dark

Question 2

The maximum reverse voltage that can be applied to an ordinary semiconductor diode without irreverslible damage is called

Accepted Answer

peak inverse voltage

Answer

cut-off voltage

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avalanche breakdown voltage

Answer

zener voltage

Question 3

The function of a zener diode, when used in a power supply, is to maintain a constant

Accepted Answer

input voltage

Answer

supply current

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output current irrespective of the load resistance

Answer

output voltage

Question 4

When bias applied to a van-cap diode is increased its capacitance

Accepted Answer

They response times are about 5 nanoseconds

Answer

When heated, their light output tends to shift to shorter wavelength

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They have rapid turn-on and turn-off times

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They emit lights of different wavelengths varying infra-red to green

Question 5

for frequencies unto GHz range

Accepted Answer

is decreased

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remains constant

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is increased

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first increases and then decreases

Question 6

Which of the following materials can be used to make a light-emitting diode?

Accepted Answer

Silicon

Answer

Germanium

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Gallium arsenide

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Phosphorescent material

Question 7

Regarding a Schottky diode which of the following statements is incorrect?

Accepted Answer

has metal-semiconductor junction

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It is a bipolar device

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has fast recovery time

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has no depletion layer

Question 8

The microwave device used as an oscillator within the frequency range 10-1000 GHz is

Accepted Answer

IMPATT diode

Answer

step recovery diode

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Gunn diode

Answer

Schottky diode

Question 9

Which of the following statements is correct regarding a step-recovery diode?

Accepted Answer

It is an ideal rectifier of high frequency signals

Answer

It has an extremely short recovery time

Answer

It conducts equally well in both directions

Answer

It is mainly used as a harmonic generator