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ELEX 4

ELEX 4

100問 • 2年前

問題一覧

1

In which materials do conduction and valence bands overlap

conductors

2

For a photoconductor with equal electron and hole mobilities and perfect ohmic contacts at the ends, an increase in illumination results in

a decrease in resistance

3

The number of p-n junctions in a semiconductor diode are

1

4

A high junction temperature may destroy a _____

diode

5

When diode is not conducting, its bias is

zero or reverse

6

The SCR would be turned off by voltage reversal of applied anode-cathode ac supply of frequency of ____

5 kHz

7

An electron rises through a voltage of 100 V. The energy acquired by it will be ____

100 eV

8

A varactor diode has

a voltage variable capacitance

9

The most important set of specifications of transformer oil includes

dielectric strength, flash point and viscosity

10

In Hall effect the O.C. transverse voltage developed by a current carrying semiconductor with a steady magnetic field perpendicular to the current direction has

opposite signs for n and p-semiconductors

11

A voltage of 9 V is applied in forward direction to a semiconductor diode in series with a load resistance of 1000Ω. The voltage across the load resistance is zero. it indicates that ____

diode is open circuited

12

When reverse voltage across a p-n junction is increased, the junction capacitance

decreases

13

______ is directly proportional to thickness

Capacitance

14

In a n type semiconductor

number of free electrons is much greater than the number of holes

15

Electron can be emitted from a metal due to

high electric field

16

In an n type semiconductor, the Fermi Level is 0.35 eV below the conduction band, the concentration of donor atoms is increased to three times. The new position of Fermi Level will be

about 0.32 eV below conduction band

17

In a BJT, the base region is ____

thin

18

In p-n-p transistor most of holes given off by emitter

diffuse through base

19

The behaviour of FET is similar to that of

pentode

20

SCR can be turned on by 1. Applying anode voltage at a sufficient fast rate 2. Applying sufficiently large anode voltage 3. Increasing the temperature of SCR to a sufficient 4. Applying sufficiently large gate current

1, 2, 3, 4

21

If for a silicon n-p-n transistor, the base to emitter voltage (Vbe) is 0.7 V and the collector to base voltage Vcb is 0.2 V, then the transistor is operating in

normal active mode

22

The number of doped regions in a bipolar junction transistor is

3

23

Donot energy level is n type semiconductor is very near valence band

False

24

GaAs has an energy gap of 1.43 eV, the optical cut off wavelength of GaAs would lie in the

infrared region of the spectrum

25

When the i-v curve of a photodiode passes through origin, the illumination is

zero

26

The threshold voltage of MOSFET can be lowered by 1. Using thin gate oxide 2. Reducing the substrate concentration 3. Increasing the substrate concentration

1 and 3

27

In which device does the extent of light controls the conduction

Photo sensitive device

28

An increase in junction temperature of a semiconductor diode causes _____ in reverse saturation current

large increase

29

An air gap provided in the iron core of an inductor prevents

core saturation

30

Which of these has a layer of intrinsic semiconductor?

PIN Diode

31

When diode used as rectifier the reverse breakdown voltage

should not be exceeded

32

A Si sample is doped with a fixed number of group N impurities. The electron density n is measured from 4 K to 1200 K for the sample. Which one of the following is correct?

n increases monotonically with increasing temp

33

In design of circuit using BJT, a ______ is used.

derating factor

34

As the ambient temperature increases, heat dissipation becomes ______

slower

35

The behaviour of a JFET is similar to that of

Vacuum triode

36

What is the effect of cut in voltage on the wave form of output as compared to input in a semiconductor diode?

Output voltage is more than input voltage

37

As temperature increases the number of free electrons and holes in an intrinsic semiconductor

increases

38

At room temperature kT = ____

0.03 eV

39

A JFET behaves as a resistor when

Vgs < Vp

40

When Vgs < Vp, the drain current in a JFET is _____

almost constant

41

Dielectric strength of polythene is around

40 kV/mm

42

Resistivity of hard drawn copper is

more than that of annealed copper

43

The channel in JFET consists of

either p or ntype material

44

The voltage across the secondary of the transformer in a half wave rectifier with a shunt capacitor filter is 50 volts. The maximum voltage will occur on the reverse biased diode will be

100 V

45

For a photoengraving the mask used is

working mask

46

In a varactor diode, the increase in width of depletion layer results in

decrease in capacitance

47

The diameter of an atom is

10^(-10) metre

48

When a p-n junction is reverse biased

holes and electrons move away from the junction

49

lf a sample of germanium and a sample of Si have th impurity density and are kept at room temperature then

resistivity of Si will be higher than of germanium

50

When a large number of crystal are brought together to form a crystal _____ are affected appreciably by the presence of other neighbouring atoms

the energy levels of outer shell electrons

51

At room temperature the barrier potential in a silicon diode is

0.7 V

52

The cut in voltage of a diode is nearly equal to

barrier potential

53

Which of the following devices had substrate?

Depletion and Enhancement type MOSFET

54

The amount of photoelectric emission depends on the ______

intensity of the incident light

55

In degenerate p type semiconductor material, the Fermi Level

is in conduction band

56

In active filter circuits, inductances are avoided mainly because they

are bulky and unsuitable for miniaturisation

57

When p-n-p is operating in active region, the current in the n region is due to

mainly holes

58

In a JFET

drain current is nearly equal to source current

59

Consider the following statements: The function of oxide layer in an IC device us to 1. mask against diffusion ir non implant 2. insulate the surface electrically 3. increase the melting point of silicon 4. produce a chemically stable protective layer

1, 2, 4 are correct

60

An extrinsic semiconductor sample has 6 billion atoms and 3 million pentavalent impurity atoms. The number of electrons and holes is

3 million free electrons and very small number of holes

61

Photoconductive devices uses

semiconductors

62

Which of the following devices are voltage controlled devices?

Vacuum Tube and FET

63

In a photodiode the current is due to

minority carriers

64

When an electron breaks covalent bond and moves away,

a hole is created

65

In a JFET, the drain current is maximum when

Vgs = 0

66

A 2 bit binary multiplier can be implemented using

2 I/P XORs and 4 I/P AND only

67

Which of the following oscillators is suitable for frequencies in the range of MegaHertz?

Hartley

68

In figure v1 = 8 V and v2 = 4 V. Which diode will conduct?

D1 only

69

To protect the diodes in a rectifier and capacitor input filter, it is necessary to use

Surge Resistor

70

In figure V1 = 8 V and V2 = 8 V. Which diode will conduct?

Both D1 and D2

71

The main advantage of CMOS circuit

low power consumption

72

In a series inverter supplying a load resistance R, the commutating elements L and C should be that

R² < 4L/C

73

Which is not part of Executing Unit (EU)?

Clock

74

An example of a pnp silicon transistor is 2N4123

False

75

Which of the following is (are) terminal (s) of a transistor?

All of the above

76

What does a reading of a large or small resistance in forward- and reverse-biased conditions indicate when checking a transistor using an ohmmeter?

Faulty device

77

What range of resistor values would you get when checking a transistor for forward- and reverse-biased conditions by an ohmmeter?

100 Ohm to a few k Ohm, exceeding 100 k Ohm

78

Calculate minority current ICO if IC = 20.002 mA and IC majority = 20 mA.

2 uA

79

What is (are) the component(s) of electrical characteristics on the specification sheets?

All of the above

80

Which of the following equipment can check the condition of a transistor?

All of the above

81

For what kind of amplifications can the active region of the common-emitter configuration be used?

All of the above

82

Which of the following can be obtained from the last scale factor of a curve tracer?

β ac

83

B dc =

Ic / Ib

84

How many carriers participate in the injection process of a unipolar device?

1

85

What is the most frequently encountered transistor configuration?

Common Emitter

86

How many individual pnp silicon transistors can be housed in a 14-pin plastic dual-in-line package?

4

87

In what decade was the first transistor created?

1940

88

Most specification sheets are broken down into ________.

All of the above

89

For a properly biased pnp transistor, let IC = 10 mA and IE = 10.2 mA. What is the level of IB?

200 uA

90

What is the ratio of the total width to that of the center layer for a transistor?

150 : 1

91

Which component of the collector current IC is called the leakage current?

Minority

92

What is the color code of 220 Ohm, 5% Resistor?

Red, Red, Brown, Gold

93

Name the component

Schmitt Trigger

94

This stage is called

Common Emitter

95

The parallel transmission of digital data:

requires as many signal lines between sender and receiver as there are data bits.

96

Because microprocessor CPUs do not understand mnemonics as they are, they have to be converted to ________.

binary machine code

97

A register in the microprocessor that keeps track of the answer or results of any arithmetic or logic operation is the:

accumulator

98

What type of circuit is used at the interface point of an input port?

latch

99

The number of 16k x 4, memories needed to construct a 128k x 8 memory is ____

16

100

What is the device shown in the figure below?

Silicon Bilateral Switch

Basic Communication I

Basic Communication I

John Cerda · 100問 · 2年前

Basic Communication I

Basic Communication I

100問 • 2年前

Basic Communication II

Basic Communication II

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Basic Communication II

Basic Communication II

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Basic Communication III

Basic Communication III

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Basic Communication III

Basic Communication III

50問 • 2年前

Amplitude Modulation I

Amplitude Modulation I

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Amplitude Modulation I

Amplitude Modulation I

100問 • 2年前

Amplitude Modulation II

Amplitude Modulation II

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Amplitude Modulation II

Amplitude Modulation II

100問 • 2年前

Angle Modulation I

Angle Modulation I

John Cerda · 100問 · 2年前

Angle Modulation I

Angle Modulation I

100問 • 2年前

Angle Modulation II

Angle Modulation II

John Cerda · 58問 · 2年前

Angle Modulation II

Angle Modulation II

58問 • 2年前

Transmission Line I

Transmission Line I

John Cerda · 100問 · 2年前

Transmission Line I

Transmission Line I

100問 • 2年前

Transmission Line II

Transmission Line II

John Cerda · 37問 · 2年前

Transmission Line II

Transmission Line II

37問 • 2年前

Differential Calculus

Differential Calculus

John Cerda · 84問 · 2年前

Differential Calculus

Differential Calculus

84問 • 2年前

Integral Calculus

Integral Calculus

John Cerda · 53問 · 2年前

Integral Calculus

Integral Calculus

53問 • 2年前

DC Circuit

DC Circuit

John Cerda · 63問 · 2年前

DC Circuit

DC Circuit

63問 • 2年前

Differential Equation

Differential Equation

John Cerda · 21問 · 2年前

Differential Equation

Differential Equation

21問 • 2年前

ELEX 2

ELEX 2

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ELEX 2

ELEX 2

100問 • 2年前

ELEX 3

ELEX 3

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ELEX 3

ELEX 3

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ELEX 5

ELEX 5

John Cerda · 59問 · 2年前

ELEX 5

ELEX 5

59問 • 2年前

MATH

MATH

John Cerda · 78問 · 2年前

MATH

MATH

78問 • 2年前

問題一覧

1

In which materials do conduction and valence bands overlap

conductors

2

For a photoconductor with equal electron and hole mobilities and perfect ohmic contacts at the ends, an increase in illumination results in

a decrease in resistance

3

The number of p-n junctions in a semiconductor diode are

1

4

A high junction temperature may destroy a _____

diode

5

When diode is not conducting, its bias is

zero or reverse

6

The SCR would be turned off by voltage reversal of applied anode-cathode ac supply of frequency of ____

5 kHz

7

An electron rises through a voltage of 100 V. The energy acquired by it will be ____

100 eV

8

A varactor diode has

a voltage variable capacitance

9

The most important set of specifications of transformer oil includes

dielectric strength, flash point and viscosity

10

In Hall effect the O.C. transverse voltage developed by a current carrying semiconductor with a steady magnetic field perpendicular to the current direction has

opposite signs for n and p-semiconductors

11

A voltage of 9 V is applied in forward direction to a semiconductor diode in series with a load resistance of 1000Ω. The voltage across the load resistance is zero. it indicates that ____

diode is open circuited

12

When reverse voltage across a p-n junction is increased, the junction capacitance

decreases

13

______ is directly proportional to thickness

Capacitance

14

In a n type semiconductor

number of free electrons is much greater than the number of holes

15

Electron can be emitted from a metal due to

high electric field

16

In an n type semiconductor, the Fermi Level is 0.35 eV below the conduction band, the concentration of donor atoms is increased to three times. The new position of Fermi Level will be

about 0.32 eV below conduction band

17

In a BJT, the base region is ____

thin

18

In p-n-p transistor most of holes given off by emitter

diffuse through base

19

The behaviour of FET is similar to that of

pentode

20

SCR can be turned on by 1. Applying anode voltage at a sufficient fast rate 2. Applying sufficiently large anode voltage 3. Increasing the temperature of SCR to a sufficient 4. Applying sufficiently large gate current

1, 2, 3, 4

21

If for a silicon n-p-n transistor, the base to emitter voltage (Vbe) is 0.7 V and the collector to base voltage Vcb is 0.2 V, then the transistor is operating in

normal active mode

22

The number of doped regions in a bipolar junction transistor is

3

23

Donot energy level is n type semiconductor is very near valence band

False

24

GaAs has an energy gap of 1.43 eV, the optical cut off wavelength of GaAs would lie in the

infrared region of the spectrum

25

When the i-v curve of a photodiode passes through origin, the illumination is

zero

26

The threshold voltage of MOSFET can be lowered by 1. Using thin gate oxide 2. Reducing the substrate concentration 3. Increasing the substrate concentration

1 and 3

27

In which device does the extent of light controls the conduction

Photo sensitive device

28

An increase in junction temperature of a semiconductor diode causes _____ in reverse saturation current

large increase

29

An air gap provided in the iron core of an inductor prevents

core saturation

30

Which of these has a layer of intrinsic semiconductor?

PIN Diode

31

When diode used as rectifier the reverse breakdown voltage

should not be exceeded

32

A Si sample is doped with a fixed number of group N impurities. The electron density n is measured from 4 K to 1200 K for the sample. Which one of the following is correct?

n increases monotonically with increasing temp

33

In design of circuit using BJT, a ______ is used.

derating factor

34

As the ambient temperature increases, heat dissipation becomes ______

slower

35

The behaviour of a JFET is similar to that of

Vacuum triode

36

What is the effect of cut in voltage on the wave form of output as compared to input in a semiconductor diode?

Output voltage is more than input voltage

37

As temperature increases the number of free electrons and holes in an intrinsic semiconductor

increases

38

At room temperature kT = ____

0.03 eV

39

A JFET behaves as a resistor when

Vgs < Vp

40

When Vgs < Vp, the drain current in a JFET is _____

almost constant

41

Dielectric strength of polythene is around

40 kV/mm

42

Resistivity of hard drawn copper is

more than that of annealed copper

43

The channel in JFET consists of

either p or ntype material

44

The voltage across the secondary of the transformer in a half wave rectifier with a shunt capacitor filter is 50 volts. The maximum voltage will occur on the reverse biased diode will be

100 V

45

For a photoengraving the mask used is

working mask

46

In a varactor diode, the increase in width of depletion layer results in

decrease in capacitance

47

The diameter of an atom is

10^(-10) metre

48

When a p-n junction is reverse biased

holes and electrons move away from the junction

49

lf a sample of germanium and a sample of Si have th impurity density and are kept at room temperature then

resistivity of Si will be higher than of germanium

50

When a large number of crystal are brought together to form a crystal _____ are affected appreciably by the presence of other neighbouring atoms

the energy levels of outer shell electrons

51

At room temperature the barrier potential in a silicon diode is

0.7 V

52

The cut in voltage of a diode is nearly equal to

barrier potential

53

Which of the following devices had substrate?

Depletion and Enhancement type MOSFET

54

The amount of photoelectric emission depends on the ______

intensity of the incident light

55

In degenerate p type semiconductor material, the Fermi Level

is in conduction band

56

In active filter circuits, inductances are avoided mainly because they

are bulky and unsuitable for miniaturisation

57

When p-n-p is operating in active region, the current in the n region is due to

mainly holes

58

In a JFET

drain current is nearly equal to source current

59

Consider the following statements: The function of oxide layer in an IC device us to 1. mask against diffusion ir non implant 2. insulate the surface electrically 3. increase the melting point of silicon 4. produce a chemically stable protective layer

1, 2, 4 are correct

60

An extrinsic semiconductor sample has 6 billion atoms and 3 million pentavalent impurity atoms. The number of electrons and holes is

3 million free electrons and very small number of holes

61

Photoconductive devices uses

semiconductors

62

Which of the following devices are voltage controlled devices?

Vacuum Tube and FET

63

In a photodiode the current is due to

minority carriers

64

When an electron breaks covalent bond and moves away,

a hole is created

65

In a JFET, the drain current is maximum when

Vgs = 0

66

A 2 bit binary multiplier can be implemented using

2 I/P XORs and 4 I/P AND only

67

Which of the following oscillators is suitable for frequencies in the range of MegaHertz?

Hartley

68

In figure v1 = 8 V and v2 = 4 V. Which diode will conduct?

D1 only

69

To protect the diodes in a rectifier and capacitor input filter, it is necessary to use

Surge Resistor

70

In figure V1 = 8 V and V2 = 8 V. Which diode will conduct?

Both D1 and D2

71

The main advantage of CMOS circuit

low power consumption

72

In a series inverter supplying a load resistance R, the commutating elements L and C should be that

R² < 4L/C

73

Which is not part of Executing Unit (EU)?

Clock

74

An example of a pnp silicon transistor is 2N4123

False

75

Which of the following is (are) terminal (s) of a transistor?

All of the above

76

What does a reading of a large or small resistance in forward- and reverse-biased conditions indicate when checking a transistor using an ohmmeter?

Faulty device

77

What range of resistor values would you get when checking a transistor for forward- and reverse-biased conditions by an ohmmeter?

100 Ohm to a few k Ohm, exceeding 100 k Ohm

78

Calculate minority current ICO if IC = 20.002 mA and IC majority = 20 mA.

2 uA

79

What is (are) the component(s) of electrical characteristics on the specification sheets?

All of the above

80

Which of the following equipment can check the condition of a transistor?

All of the above

81

For what kind of amplifications can the active region of the common-emitter configuration be used?

All of the above

82

Which of the following can be obtained from the last scale factor of a curve tracer?

β ac

83

B dc =

Ic / Ib

84

How many carriers participate in the injection process of a unipolar device?

1

85

What is the most frequently encountered transistor configuration?

Common Emitter

86

How many individual pnp silicon transistors can be housed in a 14-pin plastic dual-in-line package?

4

87

In what decade was the first transistor created?

1940

88

Most specification sheets are broken down into ________.

All of the above

89

For a properly biased pnp transistor, let IC = 10 mA and IE = 10.2 mA. What is the level of IB?

200 uA

90

What is the ratio of the total width to that of the center layer for a transistor?

150 : 1

91

Which component of the collector current IC is called the leakage current?

Minority

92

What is the color code of 220 Ohm, 5% Resistor?

Red, Red, Brown, Gold

93

Name the component

Schmitt Trigger

94

This stage is called

Common Emitter

95

The parallel transmission of digital data:

requires as many signal lines between sender and receiver as there are data bits.

96

Because microprocessor CPUs do not understand mnemonics as they are, they have to be converted to ________.

binary machine code

97

A register in the microprocessor that keeps track of the answer or results of any arithmetic or logic operation is the:

accumulator

98

What type of circuit is used at the interface point of an input port?

latch

99

The number of 16k x 4, memories needed to construct a 128k x 8 memory is ____

16

100

What is the device shown in the figure below?

Silicon Bilateral Switch