Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

eda > final > Flashcards

final Flashcards

(123 cards)

Start Studying
1
Q

What is the bandgap of a semiconductor?

A

The energy difference between the valence band and the conduction band

The bandgap determines the electrical conductivity of the semiconductor.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which of the following materials is a commonly used intrinsic semiconductor?

A

Silicon (Si)

Silicon is the most widely used semiconductor in electronics.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The majority charge carriers in an n-type semiconductor are:

A

Electrons

N-type semiconductors are doped with elements that provide extra electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which of the following elements is typically used to dope silicon to create an n-type semiconductor?

A

Phosphorus (P)

Phosphorus has five valence electrons, making it an effective n-type dopant.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The Fermi level in an intrinsic semiconductor is located:

A

In the middle of the bandgap

The Fermi level indicates the energy level at which the probability of finding an electron is 50%.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the effect of increasing temperature on the conductivity of an intrinsic semiconductor?

A

Conductivity increases

Higher temperatures provide energy to electrons, allowing them to move more freely.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which of the following is a property of a semiconductor in its intrinsic form?

A

It has a very low electrical conductivity

Intrinsic semiconductors are not very conductive compared to metals.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In an n-type semiconductor, what is the role of the donor impurity?

A

To donate electrons to the conduction band

Donor impurities are elements that provide extra electrons for conduction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the term for a material that has both p-type and n-type regions in close proximity, forming a junction?

A

P-N junction

P-N junctions are fundamental to many semiconductor devices, including diodes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which of the following is true about a p-type semiconductor?

A

The majority charge carriers are holes

P-type semiconductors are doped with elements that create holes in the valence band.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The process of adding impurities to a semiconductor to modify its electrical properties is called:

A

Doping

Doping is crucial for creating n-type and p-type semiconductors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

At absolute zero (0 K), an intrinsic semiconductor behaves as:

A

A perfect insulator

At absolute zero, there are no free charge carriers available for conduction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which of the following is the main reason that a semiconductor behaves differently from an insulator?

A

The energy gap between the valence band and conduction band is small in a semiconductor

This small gap allows for easier excitation of electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens when a forward bias is applied to a p-n junction?

A

The current increases as charge carriers move across the junction

Forward bias reduces the barrier for charge carrier movement.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

In a diode, the forward voltage drop is typically around:

A

0.7 V

This is a common voltage drop for silicon diodes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which of the following statements is true about an intrinsic semiconductor?

A

The number of free electrons equals the number of holes

In intrinsic semiconductors, electron-hole pairs are generated equally.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which of the following is NOT a semiconductor material?

A

Copper (Cu)

Copper is a conductor, not a semiconductor.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which of the following is a key difference between intrinsic and extrinsic semiconductors?

A

Intrinsic semiconductors are pure materials, while extrinsic semiconductors are created by doping

Extrinsic semiconductors have enhanced conductivity due to dopants.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Which of the following materials is commonly used for optoelectronic devices such as LEDs and laser diodes?

A

Gallium arsenide (GaAs)

GaAs is known for its efficiency in light emission.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the typical energy bandgap for a silicon semiconductor?

A

1.1 eV

This energy bandgap is essential for silicon’s semiconductor properties.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

In a p-n junction diode, when reverse bias is applied, the current is:

A

Zero or very small

Reverse bias widens the depletion region, limiting current flow.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

In a p-type semiconductor, the majority carriers are:

A

Holes

Holes represent the absence of electrons in the valence band.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Which of the following is a characteristic of an n-type semiconductor?

A

The majority charge carriers are electrons

N-type semiconductors are characterized by excess electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

In the context of semiconductors, the term ‘depletion region’ refers to:

A

A region where there are no free charge carriers due to recombination

This region forms at the p-n junction and is crucial for diode operation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What happens when a semiconductor is doped with a Group V element such as phosphorus?
It becomes an n-type semiconductor ## Footnote Group V elements provide additional electrons for conduction.
26
What is the primary function of a diode?
To allow current to flow in one direction only ## Footnote Diodes are essential for controlling current flow in circuits.
27
In a p-n junction diode, when the p-type is connected to the positive terminal of the battery and the n-type to the negative terminal, the diode is in:
Forward bias ## Footnote This configuration allows current to flow through the diode.
28
What happens to the current in a diode when it is reverse biased?
The current remains zero (except for leakage current) ## Footnote Reverse bias prevents significant current flow through the diode.
29
Which of the following is true for a diode in forward bias?
The current flows easily through the diode ## Footnote Forward bias reduces the barrier for charge carriers.
30
What is the typical voltage drop across a silicon diode when it is forward biased and conducting?
0.7 V ## Footnote This voltage drop is characteristic of silicon diodes.
31
In a p-n junction diode, what causes the depletion region to form?
Movement of charge carriers (electrons and holes) across the junction ## Footnote This movement leads to recombination and the formation of the depletion region.
32
Which of the following is true for a Zener diode in reverse bias?
It conducts current only when the reverse voltage exceeds the Zener breakdown voltage ## Footnote Zener diodes are used for voltage regulation in circuits.
33
A diode that allows current to flow in both directions, but in a controlled manner, is known as:
A Zener diode ## Footnote Zener diodes are specifically designed for reverse breakdown operation.
34
What happens when a diode is in its breakdown region?
The diode allows a large current to pass in reverse bias ## Footnote This is a critical feature of Zener diodes for voltage regulation.
35
The I-V characteristic curve of a diode shows that in reverse bias, the current:
Remains zero until breakdown voltage is reached ## Footnote This behavior is typical for diodes under reverse bias.
36
Which of the following diodes is specifically designed for light emission?
Light Emitting Diode (LED) ## Footnote LEDs are used in displays and lighting applications.
37
What is the main difference between a Zener diode and a regular diode?
A Zener diode is designed to operate in reverse breakdown for voltage regulation ## Footnote Regular diodes are not intended for breakdown operation.
38
What is the typical use of a Schottky diode?
For fast switching applications ## Footnote Schottky diodes are favored in high-speed circuit designs.
39
Which of the following is true for a diode in the 'cut-off' region?
The diode is reverse biased and does not conduct ## Footnote The cut-off region is essential for switching applications.
40
In a P-N junction diode, which region contains the majority charge carriers (electrons in n-type and holes in p-type)?
Both the n-type and p-type regions ## Footnote These regions are where charge carriers are concentrated.
41
Which type of diode is used in reverse bias to protect circuits from high voltage spikes?
Zener diode ## Footnote Zener diodes are effective for voltage clamping in circuits.
42
In a p-n junction diode, which of the following occurs when it is forward biased?
Electrons from the n-region flow toward the p-region ## Footnote This flow of electrons is essential for conduction in the diode.
43
What is the purpose of a rectifier diode in a power supply circuit?
To convert AC voltage to DC voltage ## Footnote Rectifier diodes are crucial for power supply design.
44
What is the main characteristic of a Tunnel diode?
It exhibits quantum tunneling and has a very small breakdown region ## Footnote Tunnel diodes are used in high-frequency applications.
45
Which diode is most commonly used in voltage regulation?
Zener diode ## Footnote Zener diodes provide stable voltage references.
46
In a diode, the term 'reverse recovery time' refers to:
The time the diode takes to switch from conducting to non-conducting state in reverse bias ## Footnote This time is critical for high-speed applications.
47
Which of the following is true for an ideal diode?
It has no forward voltage drop ## Footnote Ideal diodes are theoretical constructs used for circuit analysis.
48
Which of the following diodes is used for switching applications due to its very fast switching time?
Schottky diode ## Footnote Schottky diodes are preferred in applications requiring rapid switching.
49
In the I-V characteristic curve of a diode, what is the region where the current increases rapidly with a small increase in voltage after the threshold?
Forward bias region ## Footnote This region is crucial for the operation of diodes in circuits.
50
What is the effect of increasing temperature on the reverse current in a diode?
The reverse current increases exponentially ## Footnote Higher temperatures increase the thermal generation of charge carriers.
51
What is the primary function of a Bipolar Junction Transistor (BJT)?
To amplify signals ## Footnote BJTs are widely used in analog circuits for signal amplification.
52
In a BJT, the base current (Ib) is:
Proportional to the emitter current (Ie) ## Footnote The relationship between base and emitter currents is defined by the transistor's current gain.
53
What is the primary function of a Bipolar Junction Transistor (BJT)?
To amplify signals
54
In a BJT, the base current (Ib) is:
Proportional to the emitter current (Ie)
55
Which of the following is the correct relationship between the collector current (Ic), base current (Ib), and emitter current (Ie) in a BJT?
Ie = Ic + Ib
56
In an NPN transistor, the collector current (Ic) is primarily due to the movement of:
Electrons
57
Which of the following statements is true for a BJT in the active region?
The base-emitter junction is forward-biased, and the base-collector junction is reverse-biased
58
In a PNP transistor, the majority charge carriers in the emitter are:
Holes
59
What is the typical current gain (β) for a BJT?
Varies widely but typically between 20 and 1000
60
In a BJT, the relationship between the collector current (Ic) and the base current (Ib) can be expressed as:
Ic = β * Ib
61
The region of a BJT where both the base-emitter and base-collector junctions are reverse-biased is called:
Cutoff region
62
What is the typical voltage drop across a forward-biased base-emitter junction of a silicon BJT?
0.7 V
63
Which of the following is true for a BJT in saturation mode?
The base-emitter junction is forward-biased, and the base-collector junction is forward-biased
64
In a common-emitter configuration, the input signal is applied to the:
Base
65
In a common-emitter configuration, the output signal is taken from the:
Collector
66
For a BJT, what happens to the collector current (Ic) if the base current (Ib) is increased?
Ic increases proportionally
67
Which of the following factors influences the current gain (β) of a BJT?
* The size of the base * The temperature * The emitter doping level * All of the above
68
Which configuration of a BJT is most commonly used for amplification?
Common-emitter configuration
69
The small-signal model of a BJT in the active region is characterized by:
A dynamic resistance between the base and emitter
70
In the common-emitter configuration, the output voltage is inverted with respect to the input voltage. This inversion occurs because of:
The phase shift introduced by the transistor's active region
71
Which of the following is a characteristic of a BJT in the cutoff region?
The collector current is almost zero
72
The maximum collector current (Ic) that a BJT can handle is determined by:
The thermal limitations of the device
73
In a BJT, what is the main role of the base region?
To control the flow of charge carriers between the collector and emitter
74
Which of the following is true for a transistor in the saturation region?
The transistor is completely 'on,' with both junctions forward-biased
75
The term 'β' for a BJT refers to the:
Current gain
76
What is the effect of increasing the base-emitter voltage (Vbe) in a BJT?
The collector current increases exponentially
77
What is the approximate value of β (current gain) for an average BJT?
100
78
In a transistor biasing circuit, the purpose of biasing is to:
Ensure the transistor operates in the active region
79
Which of the following biasing techniques is most commonly used for small signal amplifiers due to its stability?
Voltage divider bias
80
What is the primary drawback of the fixed bias method for transistor biasing?
Poor stability of operating point
81
In the voltage divider biasing method, what determines the stability of the operating point?
The resistors in the voltage divider network
82
In the emitter bias circuit, the emitter resistor improves the circuit’s:
Stability against temperature variations
83
For a transistor operating in the active region, which of the following conditions is true?
VBE > 0.7V for a silicon transistor
84
In the voltage divider bias circuit, the stability factor (S) is defined as:
The ratio of the change in base voltage to the change in emitter current
85
In a transistor biasing circuit, the quiescent point (Q-point) is defined by which of the following?
The collector-emitter voltage (VCE) and collector current (IC)
86
Which transistor configuration is most commonly used for high-gain voltage amplification, requiring a high input impedance and low output impedance?
Common emitter (CE)
87
In the collector feedback biasing circuit, the feedback resistor is connected between the:
Collector and base
88
In the voltage divider biasing method, the emitter resistor (RE) is primarily used to:
Stabilize the operating point against temperature variations
89
In a common emitter transistor amplifier, the voltage gain is mainly determined by:
The collector resistor and the emitter current
90
Which of the following is the most important factor affecting the stability of the operating point in a transistor amplifier?
The emitter resistor (RE)
91
In a voltage divider bias circuit, what is the typical function of the resistors R1 and R2?
Provide a stable base bias voltage to the transistor
92
The fixed bias circuit is most sensitive to changes in which of the following?
Base-emitter voltage (VBE)
93
In a transistor amplifier circuit, which of the following is used to provide stabilization for the Q-point?
A resistor in the emitter leg
94
For voltage-divider biasing, the voltage divider resistors R1 and R2 should be chosen such that:
The ratio R1/R2 is close to the required base bias voltage
95
In a common emitter amplifier, what happens to the collector current if the emitter resistor (RE) is bypassed by a capacitor?
The collector current increases
96
In the voltage divider bias configuration, if the temperature increases, what happens to the collector current (IC)?
The collector current decreases
97
Which of the following methods is used to improve the thermal stability of a transistor amplifier?
Using negative feedback
98
In a common emitter amplifier, the gain is typically defined as:
The ratio of output voltage to input voltage
99
In the voltage divider biasing circuit, the current through the voltage divider resistors R1 and R2 should ideally be:
Very small compared to the base current of the transistor
100
The emitter follower (common collector) amplifier configuration is known for:
Low voltage gain and high current gain
101
In a transistor's common base configuration, the input current is supplied to the:
Emitter
102
What is the primary disadvantage of the fixed biasing method for transistor biasing?
Poor temperature stability
103
In a voltage divider biasing circuit, the base voltage VB is given by:
104
In a common emitter amplifier, increasing the emitter resistor (RE) will result in:
Decreased voltage gain
105
What is the primary characteristic of a Common Emitter (CE) amplifier?
Low input impedance and high output impedance ## Footnote This configuration is commonly used in amplifiers for its ability to provide voltage gain.
106
In a Common Emitter (CE) amplifier, what mainly determines the voltage gain?
The collector resistor (RC) ## Footnote The collector resistor plays a crucial role in setting the gain of the amplifier.
107
In a common emitter amplifier with negative feedback, where is the feedback resistor usually placed?
Between the collector and the base ## Footnote This configuration helps stabilize the amplifier's performance.
108
Where is the input signal applied in a common base amplifier?
Emitter of the transistor ## Footnote This configuration is less common but can be useful in specific applications.
109
What is the gain characteristic of a Common Collector (CC) amplifier?
Low voltage gain and high current gain ## Footnote This makes it suitable for impedance matching.
110
What is the purpose of the coupling capacitor in a common emitter amplifier circuit?
Block the DC component of the input signal ## Footnote This allows only the AC component to pass through for amplification.
111
What is the primary function of the emitter resistor (RE) in a common emitter amplifier?
To stabilize the biasing point and reduce distortion ## Footnote This is essential for maintaining consistent performance.
112
What effect does bypassing the emitter resistor (RE) with a capacitor have on a common emitter amplifier?
It increases the voltage gain at high frequencies ## Footnote This is because the capacitor effectively removes the emitter resistor's impact at high frequencies.
113
Which BJT amplifier configuration is typically used as a voltage buffer with unity gain?
Common collector ## Footnote This configuration is often used to match impedances without gain.
114
What happens to the voltage gain when the collector resistor (RC) is increased in a common emitter amplifier?
Increased voltage gain ## Footnote The collector resistor directly influences the gain of the amplifier.
115
In a common emitter amplifier, what primarily limits the output voltage swing?
The transistor’s saturation voltage (VCE(sat)) ## Footnote This saturation voltage is a critical factor in defining the amplifier's output range.
116
What primarily determines the bandwidth of a common emitter amplifier?
The coupling and bypass capacitors ## Footnote These capacitors have a significant effect on frequency response.
117
What mainly determines the input impedance of a common emitter amplifier?
The emitter resistor (RE) ## Footnote The emitter resistor has a direct impact on how the amplifier interacts with the previous stage.
118
What is the primary disadvantage of using a common base amplifier?
It has low input impedance ## Footnote This can limit its use in certain applications where input impedance is critical.
119
What effect does a bypass capacitor across the emitter resistor have in a common emitter amplifier?
Increase the voltage gain at high frequencies ## Footnote This bypass allows for higher gain by reducing the negative feedback at those frequencies.
120
What is the purpose of negative feedback in a common emitter amplifier?
Reduce distortion and improve stability ## Footnote Negative feedback is a common technique to enhance amplifier performance.
121
What happens to the output signal if the base of the transistor in a common emitter amplifier is bypassed?
The output signal is inverted and amplified ## Footnote This illustrates the phase relationship typical of common emitter configurations.
122
In a common collector amplifier, where is the output voltage taken from?
Emitter ## Footnote This configuration provides a direct connection for the output signal.
123
What is true about the phase relationship between the input and output signals in a common emitter amplifier?
The input and output signals are 180 degrees out of phase ## Footnote This phase inversion is a key characteristic of this amplifier type.

eda (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions