ITEC 320 Test #2 Flashcards Preview

Module 4, Lesson 3 > ITEC 320 Test #2 > Flashcards

Flashcards in ITEC 320 Test #2 Deck (107):
1

Transistor

A solid-state device made of semiconductor material such as silicon or germanium.

2

Types of transistors

NPN and PNP

3

Three elements of a transistor

Base, emitter, and collector

4

Base

Inner element of a transistor. The base controls transistor action.

5

What material is the base made out of in a NPN transistor

P material

6

What material is the base made out of in a PNP transistor

N material

7

Emitter

On of the outer elements of the transistor

8

What material is the emitter made out of in a NPN transistor

N material

9

What material is the emitter made out of in a PNP transistor

P material

10

Collector

One of the other outer elements of a transistor

11

What material is the collector made out of in a NPN transistor

N material

12

What material is the collector made out of in a PNP transistor

P material

13

NPN transistor

A bipolar transistor in which outer elements (emitter and collector) are made of N-type of semiconductor material and the inner element (base) is made out of P-type material

14

PNP transistor

A bipolar transistor in which the outer elements (emitter and collector) are made out of P-type semiconductor material and the inner element (base) is made out of N-type material

15

P-type material

Semiconductor material that is doped with very small amounts of acceptor impurity materials that decrease active electrons.

16

What are the majority charge carriers in P-type materials

Holes

17

N-type material

Semiconductor material that is doped with very small amounts of donor impurity materials that add active electrons.

18

What are the majority charge carriers in N-type materials

Electrons

19

What are 2 basic transistor types

NPN and PNP

20

How many elements does a transistor have

3 (base , emitter, and collector)

21

In the transistor schematic symbol, the arrow is on what element

Emitter

22

What is the most common problem with transistors

Overheating

23

What can you use in place of a transistor tester to check transistors

Ohmmeter

24

When reverse biased, a diode will block, pass current

Block

25

When forward biased, a diode will block, pass current

Pass

26

When testing transistors, consider them to be

Back-to-back diodes

27

A diode that is forward biased will have high, low resistance

Low

28

A diode that is reverse biased will have high, infinity resistance

Infinity

29

To test transistors to determine if they are NPN or PNP, what must you know about the ohmmeter

The negative and positive leads

30

The positive probe is on what material when a diode is reverse biased

Cathode (-)

31

The negative probe is on what material when a diode is reversed biased

Anode (+)

32

A reverse-biased junction will show what resistance reading

0.2

33

When a component is being tested with an ohmmeter, it is usually in series, parrallel with the internal supply voltage

Series

34

In a transistor, a smaller what controls the larger currents

Base

35

A NPN transistor consists of

A layer or P-type material between two layers of N-type material

36

A common transistor problem is

Shorted transistor

37

Transistors are

Reliable, but destructible

38

If both the forward and reverse emitter-base resistances are low, then the transistor is

Shortened

39

When testing transistors, you can consider them to be

Back-to-back diodes

40

When a diode is forward biased, it is indicating a

Low resistance

41

How can you indicate which leads of a transistor are P-type and which are N-type using an ohmmeter

Polarity

42

In what device does a small amount of current control a large amount of current

Transistor

43

What current determines the amount of collector current

Base current

44

Does an increase in base current cause a decrease in collector current

No

45

Does the resistance of a transistor increase or decrease with an increase of base current

Decreases

46

Common base

A transistor circuit where the base is common (circuit ground) to the input and output signals. This circuit does not produce a phase shift

47

Common emitter

A transistor circuit where the emitter is common (circuit ground) to the input and output signals. This circuit produces a 180 degree phase shift

48

Common collector

A transistor circuit where the collector is common to the input and output signals. Collector is usually an AC ground. This circuit does not produce a phase shift

49

Regardless of the circuit arrangement used, the transistor-emitter base junction must always be what bias

Forward

50

In the common-collector circuit, the input signal is applied between..........and............regions of the transistor

Base and emitter

51

Does the common-collector circuit provide an output voltage greater than its input voltage

No losses 1/10 volt

52

Does a common-emitter circuit use the same bias polarities in PNP and NPN circuits

No

53

Is the input signal to a common-emitter circuit 180 degrees out of phase with the output signal

Yes

54

Transistor power rating

The max power that a transistor can dissipate without damage to it.

55

Transistor power rating equation

P = VCE x IC

56

Can you operate transistors under a wide variety of operating voltages and currents

Yes, because it is all about how they are biased. They can't exceed their current handling or voltage drop

57

What is the max amount of power a transistor can dissipate called

Power rating

58

What results when you exceed the max power specifications of a transistor

Damage to the transistor

59

Base current (IB), is the amount that will pass from

Emitter to base

60

The base-to-emitter current, in effect, controls the

Collector current

61

For current control to take place

A transistor must be properly biased

62

For forward biasing, The P-type base material in an NPN transistor must be what with respect to the N-type emitter material

Positive

63

In use, the emitter-base voltage is usually taken from the

Collector supply

64

When a circuit increases its AC input signal to a greater amplitude, it has

Gain

65

In a common-base circuit

The base is common to both the input and output signals

66

The common-collector circuit is often used as a

Impedance-matching device

67

Energy a transistor receives when operating in a circuit is transferred as

Dissipated heat

68

Voltage regulation

The process of maintaining the output voltage a power source constant with respect to changes of input voltage and loading.

69

Voltage regulator

A circuit or device that minimizes the changes of output voltage of a power supply as the load on the supply varied

70

Percentage of regulation

The percentage by which a power supply voltage changes when a load is applied compared with full-load voltage

71

Shunt regulator

A variable device connected across the load terminals of a regulated power supply. Its resistance automatically varies the voltage across a series resistor. The resulting action maintains the load voltage at a constant level.

72

Series voltage regulator

A voltage regulator that uses an automatically variable resistance in series with the load to control the output voltage

73

Voltage regulator circuits are used to

Filter circuits and refine the filtering process

74

Voltage regulator circuits provide voltage regulation for

Power supplies

75

In a power source, each component adds up to

An internal resistance in series with the output current

76

What diode is an effective shunt regulator

Zener

77

Voltage output changes can occur because of a variation in

Line voltage input

78

The smaller the percentage of regulation

The better the regulator

79

In a shunt voltage regulator, the regulator acts as an

Resistance in parallel to the load

80

In a series voltage regulator, the regulator acts as an

Resistance in series with the load

81

One use of a series voltage regulator is as an

Ripple filter

82

An increase in current will cause the series regulator to

Decrease in resistance

83

Gain

The ratio of output signal amplitude of an amplifier to its input signal amplitude. Expressed in terms of voltage, current, or power. Can also be expressed in decibels.

84

Characterisitc curve

A graph showing the relationship between changing values, voltage, and current

85

Gain formula

Gain = output voltage / input voltage

86

Amplifier

A group of electronic components connected in such a way as to increase the strength of an electrical signal applied to its input

87

What does gain determine

The amount of amplification an amplifier can provide

88

Amplifiers increase current and

Voltage

89

Are amplifiers used to operate in different frequencies

Yes

90

Cascaded amplifiers

Two or more amplifiers connected one after another. The output of the first amplifier supplies the signal to the input of the second amplifier

91

How do you obtain large gains

Cascaded amplifiers

92

How do you determine the total gain of amplifiers in cascade

Multiplying the product of their individual gains

93

A set of characteristic curves show the relationship between

Base current and collector current

94

Each individual curve represents

A different emitter bias current

95

The vertical axis of the graph represents

Collector current

96

The horizontal axis of the graph represents

Collector voltage

97

For what can you use a set of characteristic curves

Find the operating range of the transistor

98

What is the best source for a specification sheet of a particular device

Manufacturer

99

What is the danger of exceeding maximum ratings

Overheating or damage

100

When looking at a specification sheet, how do you determine which specifications are of the greater importance

Always on the first page and labeled maximum

101

Can a transistor lead-out be found on a specification sheet

Yes

102

An amplifier is a circuit that increases the amplitude of a

Alternating waveform

103

To determine how much an amplifier can increase a signal, you determine

Gain

104

Amplifiers may amplify either

Current or voltage

105

Amplifiers that amplify both current and voltage are called

Power amps

106

When you need large gains, you can connect

Cascaded amplifiers

107

The total gain of two amplifiers connected in cascade is

The product of their individual gains