NAVEDTRA 14179A, NAVY ELECTRICITY AND ELECTRONICS TRAINING SERIES, MODULE 7-SOLID-STATE DEVICES AND POWER SUPPLIES

Question 1

Which year was the first transistor discovered?

Answer 1

1948

Question 2

What are semiconductor devices called that have-three or more elements?

Answer 2

Transistors

Question 3

In which ways are transistors classified?

Answer 3

NPN or PNP

Question 4

What were the very first transistors known as?

Answer 4

Point-contact

Question 5

Which type of transistor generates less noise, handles more power, provides higher current and voltage gains, and can be mass-produced more cheaply than the point-contact transistor?

Answer 5

Junction

Question 6

What is the process called of increasing the strength of a signal?

Answer 6

Amplification

Question 7

Which device provides amplification without appreciably altering the original signal?

Answer 7

Amplifier

Question 8

What is returning a part of the output back to its input known as?

Answer 8

Degeneration

Question 9

How many classes of amplifier operations are there?

Answer 9

Four

Question 10

Which class of amplifies are biased so that variations in input signal polarities occur within the limits of cutoff and saturation?

Answer 10

Class A

Question 11

What occurs when the base becomes so negative with respect to the emitter that changes in the signal are not reflected in collector-current flow?

Answer 11

Saturation

Question 12

Amplifiers designed for what class of operation are biased so that collector current is zero (cutoff) for a portion of one alternation of the input signal?

Answer 12

AB

Question 13

Amplifiers biased so that collector current is cut off during one-half of the input signal are classified as what class?

Answer 13

B

Question 14

What is the faithful reproduction of a signal called?

Answer 14

Fidelity

Question 15

Which amplifier property refers to the ratio of output-signal power compared to the total input power?

Answer 15

Efficiency

Question 16

Which amplifier class has the highest efficiency of the four classes of amplifier operations?

Answer 16

Class C

Question 17

How many basic configurations may a transistor be connected in?

Answer 17

Three

Question 18

What is the most frequently used arrangement in practical amplifier circuits?

Answer 18

Common-Emitter configuration (CE)

Question 19

Which term is used to describe the amplification capabilities of the amplifier?

Answer 19

Gain

Question 20

What is the relationship of collector current (output current) to base current (input current)?

Answer 20

Beta

Question 21

What is the relationship of collector current (output current) to emitter current (input current)?

Answer 21

Alpha

Question 22

Which transistor properties are the direct voltage and current values that if exceeded in operation may result in transistor failure?

Answer 22

Absolute Maximum Ratings

Question 23

What is one of the greatest dangers to the transistor which will cause excessive current flow and eventual destruction of the transistor?

Answer 23

Heat

Question 24

Gain, leakage, breakdown, along with what else are the four basic tests required for transistors in practical troubleshooting?

Answer 24

Switching time

Question 25

What is a flat insulating surface upon which printed wiring and miniaturized components are connected in a predetermined design, and attached to a common base?

Answer 25

Printed circuit board

Question 26

Printed circuit boards are stacked and connected together to form a module using what technique?

Answer 26

Modular circuitry

Question 27

Which device integrates (combines) both active components (transistors, diodes, etc.) and passive components (resistors, capacitors, etc.) of a complete electronic circuit in a single chip (a tiny slice or wafer of semiconductor crystal or insulator)?

Answer 27

Integrated Circuit

Question 28

What are the two general classifications of integrated circuits?

Answer 28

Hybrid and Monolithic

Question 29

In which type of integrated circuits do all elements (resistors, transistors, etc.) associated with the circuit fabricated inseparably within a continuous piece of material (called the SUBSTRATE) which is usually silicon?

Answer 29

Monolithic

Question 30

What are two terminal semiconductors of various types that are used in seemingly endless applications?

Answer 30

Diodes

Question 31

What is a PN junction that is designed to operate in the reverse-bias breakdown region?

Answer 31

Zener diode

Question 32

Which year was the zener effect first produced by Dr. Carl Zener?

Answer 32

1934

Question 33

Which process according to Dr. Zener's theory does electrical breakdown in solid dielectrics occur by?

Answer 33

Quantum-Mechanical tunneling

Question 34

What is a band in which the energy level of the electrons is high enough that the electrons will move easily under the influence of an external field?

Answer 34

Conduction

Question 35

What are solid materials called that have many electrons in the conduction band?

Answer 35

Conductors

Question 36

What is a band in which the energy level is the same as the valence electrons of the atoms?

Answer 36

Valence

Question 37

What is a material in which the forbidden gap is so narrow that it can be considered nonexistent?

Answer 37

Conductor

Question 38

What is a solid that contains a forbidden gap?

Answer 38

Semiconductor

Question 39

What are materials in which the forbidden gap is so large that practically no electrons can be given enough energy to cross the gap?

Answer 39

Insulators

Question 40

What is the most widespread use of Zener diodes?

Answer 40

Voltage regulators

Question 41

Which year did Leo Esaki discover that if a semiconductor junction diode is heavily doped with impurities then it will have a region of negative resistance?

Answer 41

1958

Question 42

In the tunnel diode, the semiconductor materials used in forming a junction are doped to the extent of how many impurity atoms for ten-million semiconductor atoms?

Answer 42

1000

Question 43

What is the most important and most widely used characteristic of the tunnel diode?

Answer 43

Negative resistance region

Question 44

Which type of diode behaves like a variable capacitor, with the PN junction functioning like the dielectric and plates of a common capacitor?

Answer 44

Varactor

Question 45

How high can the ratio of varactor capacitance to reverse-bias voltage change be?

Answer 45

10 to 1

Question 46

What can be used to check a varactor diode in a circuit?

Answer 46

Ohmmeter

Question 47

What functions as a switch that can turn on or off small or large amounts of power?

Answer 47

SCR

Question 48

Some SCRs can be switched how many times a second?

Answer 48

25,000

Question 49

The input resistance of the SCR is relatively low (approximately how many ohms) and requires current for triggering?

Answer 49

100

Question 50

Which type of devices either produce light or use light in their operation?

Answer 50

Optoelectronic

Question 51

LED operating voltage is small, about 1.6 volts forward bias and generally about how many milliamperes?

Answer 51

10

Question 52

What is the life expectancy of the LED?

Answer 52

100,000+ hours

Question 53

What is a light-controlled variable resistor?

Answer 53

Photodiode

Question 54

What is typical light-to-dark resistance ratio for a photocell?

Answer 54

1:1000

Question 55

Which type of device converts light energy into electrical energy?

Answer 55

Photovoltaic cell

Question 56

What is often used when it is necessary to block the voltage between one electronic circuit and another, and transfer the signal at the same time?

Answer 56

Amplifier coupling capacitor

Question 57

Transistors are semiconductor devices with how many or more terminals?

Answer 57

Three

Question 58

How many distinct types of UJTs are presently in use?

Answer 58

40+

Question 59

What uses voltage to control electrostatic field within the transistor?

Answer 59

FET

Question 60

The MOSFET has a higher input impedance than the JFET (how many megohms)?

Answer 60

10 to 100 million

Question 61

The MOSFET is normally constructed so that it operates in one of what two basic modes?

Answer 61

Depletion or Enhancement

Question 62

Most power supplies are made up of the following four basic sections: transformer, rectifier, filter, and what else?

Answer 62

Regulator

Question 63

What steps up or steps down the input line voltage and isolates the power supply from the power line?

Answer 63

Transformer

Question 64

What converts the alternating current input signal to a pulsating direct current?

Answer 64

Rectifier

Question 65

What maintains the output of the power supply at a constant level in spite of large changes in load current or input line voltages?

Answer 65

Regulator

Question 66

What provides two equal voltages to the conventional full-wave rectifier?

Answer 66

Center-tapped transformer

Question 67

What is the conversion of an alternating current to a pulsating direct current?

Answer 67

Rectification

Question 68

What is current called that flows in pulses in the same direction?

Answer 68

Pulsating DC

Question 69

Which terms are AC voltages normally specified in?

Answer 69

RMS values

Question 70

Which type of device has two or more diodes arranged so that load current flows in the same direction during each half cycle of the ac supply?

Answer 70

Full-wave rectifier

Question 71

How many basic types of filter circuits are there?

Answer 71

Four

Question 72

What is defined as the time it takes a capacitor to charge to 63.2 percent of the applied voltage or to discharge to 36.8 percent of its total charge?

Answer 72

One time constant

Question 73

What is the most basic type of power supply filter?

Answer 73

Capacitor filter

Question 74

Which type of filter is primarily used in power supplies where voltage regulation is important and where the output current is relatively high and subject to varying load conditions?

Answer 74

LC choke-input

Question 75

What percent of a half-wave rectifier is the ripple frequency of a full-wave rectifier?

Answer 75

200%

Question 76

Electrolytic capacitors are available in sizes up to how many microfarads or greater?

Answer 76

10,000

Question 77

What is one of the most commonly used filters primarily used in radio receivers, small audio amplifier power supplies, and in any type of power supply where the output current is low and the load current is relatively constant?

Answer 77

LC capacitor-input filter

Question 78

115 volts AC can vary from about 105 volts AC to how many volts AC?

Answer 78

125

Question 79

What gives an indication of how much the output voltage changes over a range of load resistance values?

Answer 79

Figure of merit

Question 80

Basic voltage regulators are classified as one of what two ways?

Answer 80

Series or shunt

Question 81

Which type of diode blocks current until a specified voltage is applied?

Answer 81

Zener diode

Question 82

Which circuitry provides a constant current output?

Answer 82

Current regulator

Question 83

What are used primarily to develop high voltages where low current is required?

Answer 83

Voltage multipliers

Question 84

The DC output of the voltage multiplier ranges from 1000 to how many volts?

Answer 84

30,000

Question 85

In order for a silicon NPN transistor to conduct, the base must be between how many volts more positive than the emitter?

Answer 85

0.6 to 0.7 volts

Question 86

What are the two widely used checks in testing electronic equipment?

Answer 86

Signal tracing and Visual

Question 87

What is a short-circuit protection device that automatically limits the current to a safe value?

Answer 87

Current Limiter