FET Amplifiers: Interactive Learning Quizzes for Electronics II

Question 1

Which characteristic distinguishes a common-source FET amplifier?

Accepted Answer

High input impedance and voltage gain greater than unity

Answer

High input impedance and low output impedance

Answer

Low input impedance and high output impedance

Answer

Low input impedance and low output impedance

Question 2

In a common-gate FET amplifier, the input signal is connected to the:

Accepted Answer

Source terminal

Answer

Gate terminal

Answer

Drain terminal

Answer

Body terminal

Question 3

Which frequency response characteristic is NOT applicable to FET amplifiers?

Accepted Answer

Resonance frequency

Answer

High-frequency roll-off

Answer

Low-frequency roll-off

Answer

Mid-frequency gain

Question 4

Which components are included in a FET amplifier's small-signal model?

Accepted Answer

Voltage-controlled current source, resistor representing channel resistance, and capacitor representing gate-source capacitance

Answer

Voltage-controlled current source and resistor representing channel resistance

Answer

Resistor representing channel resistance and capacitor representing gate-source capacitance

Answer

Capacitor representing gate-source capacitance and resistor representing load resistance

Question 5

Which advantage do FET amplifiers offer over BJT amplifiers in high-frequency applications?

Accepted Answer

Wider bandwidth

Answer

Higher transconductance

Answer

Lower noise figure

Answer

Greater power dissipation

Question 6

The transconductance of a FET amplifier represents its:

Accepted Answer

Current gain

Answer

Voltage gain

Answer

Power gain

Answer

Frequency response

Question 7

In a common-source FET amplifier, to which terminal is the input signal applied?

Accepted Answer

Gate

Answer

Source

Answer

Drain

Answer

Body

Question 8

Which type of feedback can be used to enhance the linearity of a FET amplifier?

Accepted Answer

Negative feedback

Answer

Positive feedback

Answer

Voltage feedback

Answer

Current feedback

Question 9

Which parameter primarily controls the drain current in a FET?

Accepted Answer

Gate-to-source voltage

Answer

Drain-to-source voltage

Answer

Body-to-source voltage

Answer

Temperature

Question 10

The transfer characteristic of a FET is typically:

Accepted Answer

Exponential

Answer

Linear

Answer

Parabolic

Answer

Hyperbolic

Question 11

In a common-source FET amplifier, the input signal is applied to the what terminal?

Accepted Answer

Gate

Answer

Source

Answer

Drain

Question 12

The transconductance of a FET is defined as the ratio of what two quantities?

Accepted Answer

Output current to input voltage

Answer

Input voltage to output current

Answer

Output voltage to input current

Question 13

The mid-band gain of a common-drain FET amplifier is approximately equal to what value?

Accepted Answer

1

Answer

g_m*R_L

Answer

R_L/g_m

Question 14

A JFET is a type of FET that uses a what type of junction?

Accepted Answer

p-n junction

Answer

p-n-p junction

Answer

n-p-n junction

Question 15

The gate of a MOSFET is usually made of what material?

Accepted Answer

Metal

Answer

Silicon

Answer

Insulator

Question 16

Which configuration is **not** a type of FET amplifier?

Accepted Answer

Common-emitter

Answer

Common-source

Answer

Common-gate

Answer

Common-drain

Question 17

In a common-source FET amplifier, where is the gate terminal connected?

Accepted Answer

Input signal

Answer

Ground

Answer

Output signal

Answer

Source terminal

Question 18

What is the primary purpose of a bypass capacitor in a FET amplifier circuit?

Accepted Answer

Provide a low-impedance path for AC signals

Answer

Reduce the DC gain of the amplifier

Answer

Increase the bandwidth of the amplifier

Answer

Decrease the input impedance of the amplifier

Question 19

Which benefit is provided by incorporating a negative feedback loop in a FET amplifier?

Accepted Answer

Reduced distortion

Answer

Increased gain

Answer

Increased bandwidth

Answer

Lower noise

Question 20

In a depletion-mode FET, the channel is:

Accepted Answer

Always present

Answer

Present only with a positive gate-source voltage

Answer

Present only with a negative gate-source voltage

Answer

Never present

Question 21

Which of the following are the main sources of noise in FET amplifiers?

Accepted Answer

Thermal noise, shot noise, and flicker noise

Answer

Thermal noise and flicker noise only

Answer

Shot noise and flicker noise only

Answer

Thermal noise only

Question 22

Which technique is LEAST likely to improve the frequency response of an FET amplifier?

Accepted Answer

Increasing the load capacitance

Answer

Connecting multiple amplifier stages

Answer

Using FETs designed for high frequencies

Answer

Applying negative feedback

Question 23

In a common-gate FET amplifier, what is the primary function of the source terminal?

Accepted Answer

Biasing reference voltage

Answer

Input signal source

Answer

Output signal source

Answer

Feedback signal source

Question 24

In a common-source JFET amplifier, the input signal is applied to the:

Accepted Answer

Gate

Answer

Drain

Answer

Source

Question 25

The common-gate JFET amplifier configuration has a:

Accepted Answer

High input impedance

Answer

Low input impedance

Answer

High voltage gain

Question 26

The frequency response of a JFET amplifier can be affected by:

Accepted Answer

Input and output capacitances

Answer

Only output capacitance

Answer

Only input capacitance

Question 27

The transconductance (gm) of a JFET is a measure of its:

Accepted Answer

Current gain

Answer

Input impedance

Answer

Voltage gain

Question 28

In a JFET, the drain current (ID) is mainly controlled by:

Accepted Answer

Gate-source voltage (VGS)

Answer

Drain-source voltage (VDS)

Answer

Channel width

Question 29

A JFET amplifier incorporating a negative feedback loop will typically exhibit:

Accepted Answer

Reduced distortion

Answer

Higher power consumption

Answer

Increased voltage gain

Answer

Lower input impedance

Question 30

The threshold voltage of a JFET represents the:

Accepted Answer

Gate-source voltage required to initiate channel conduction

Answer

Voltage at which the drain current is maximum

Answer

Drain-source voltage required to terminate channel conduction

Question 31

FET amplifiers provide several benefits, but they also have inherent limitations. Which factor poses a significant challenge in FET amplifier design?

Accepted Answer

Electrostatic Discharge

Answer

High Input Impedance

Answer

Voltage-Controlled Operation

Answer

Low Power Dissipation

Question 32

Which terminal of a common-source FET amplifier receives the input signal?

Accepted Answer

Gate

Answer

Substrate

Answer

Source

Answer

Drain

Question 33

What characteristic of a common-gate FET amplifier makes it useful in high-impedance applications?

Accepted Answer

High input impedance

Answer

Low noise

Answer

Wide bandwidth

Answer

High voltage gain

Question 34

What is the primary purpose of using a source bypass capacitor in a FET amplifier?

Accepted Answer

To improve low-frequency response by reducing the voltage drop across the source resistor

Answer

To isolate the gate from the source

Answer

To increase the amplifier's bandwidth

Answer

To prevent oscillations

Question 35

In a depletion-mode JFET, what is the effect of increasing the negative gate-source voltage?

Accepted Answer

Decreases drain current

Answer

Increases drain current

Answer

Reverses the direction of drain current

Answer

Has no effect on drain current

Question 36

Which of the following is NOT an advantage of using negative feedback in a FET amplifier?

Accepted Answer

Increased gain

Answer

Extended frequency response

Answer

Improved stability

Answer

Reduced distortion

Question 37

What is the main purpose of a bias resistor in a FET amplifier?

Accepted Answer

To establish a stable DC operating point for the FET

Answer

To provide AC coupling between stages

Answer

To prevent oscillations

Answer

To limit the flow of current through the FET

Question 38

What is the primary function of the load resistor in a FET amplifier?

Accepted Answer

To provide a path for drain current to flow

Answer

To prevent oscillations

Answer

To bias the FET

Answer

To couple the amplifier to the next stage

Question 39

Which of the following FET amplifier configurations provides the highest voltage gain?

Accepted Answer

Common-Source

Answer

Common-Gate

Answer

Common-Drain

Answer

Source-Follower

Question 40

What is the primary function of a FET in an amplifier circuit?

Accepted Answer

To regulate the flow of current between the source and drain terminals based on the gate-source voltage.

Answer

To isolate the input and output signals.

Answer

To solely provide voltage amplification.

Question 41

Which of the following parameters is NOT used to characterize the small-signal model of a FET amplifier?

Accepted Answer

Reverse Transfer Capacitance

Answer

Output Resistance

Answer

Transconductance

Answer

Input Resistance

Question 42

What is the main purpose of biasing a FET amplifier?

Accepted Answer

To establish a stable operating point for the FET, ensuring proper signal amplification and minimizing distortion.

Answer

To increase the voltage gain of the amplifier alone.

Answer

To eliminate the effects of temperature variations exclusively.

Answer

To decrease the input resistance of the amplifier solely.

Question 43

What is the general effect of increasing the drain-source voltage (VDS) in a FET amplifier?

Accepted Answer

An increase in the drain current (ID).

Answer

A decrease in the voltage gain.

Answer

A decrease in the transconductance (gm).

Answer

An increase in the input resistance (Rin).

Question 44

What is the main difference between an enhancement-mode and a depletion-mode FET?

Accepted Answer

Enhancement-mode FETs require a positive gate-source voltage to turn on, while depletion-mode FETs conduct with zero gate-source voltage.

Answer

Depletion-mode FETs have a higher transconductance than enhancement-mode FETs.

Question 45

In a common-source amplifier configuration, where is the input signal applied?

Accepted Answer

Gate

Answer

Drain

Answer

Both Gate and Source

Answer

Source

Question 46

What is the primary purpose of the bypass capacitor in a common-source amplifier?

Accepted Answer

To increase the AC gain at mid-frequencies by creating a low-impedance path for the AC component of the source current, essentially grounding the source resistance for AC signals.

Answer

To stabilize the DC operating point of the FET.

Answer

To solely improve the low-frequency response of the amplifier.

Question 47

The transconductance (g_m) of an FET is a measure of:

Accepted Answer

The change in drain current (ΔID) for a given change in gate-source voltage (ΔVGS).

Answer

The input capacitance of the FET.

Answer

The output resistance of the FET.

Question 48

The Miller effect in FET amplifiers is primarily responsible for:

Accepted Answer

Increasing the effective input capacitance at high frequencies due to the interaction between the gate-source capacitance and the drain-gate capacitance.

Answer

Reducing the voltage gain at low frequencies.

Answer

Introducing distortion into the output signal.

Question 49

The small-signal model of an FET is used to analyze the amplifier's:

Accepted Answer

AC behavior around a specific operating point.

Answer

DC operating point.

Answer

Transient response.

Answer

Large-signal behavior.

Question 50

A common-drain amplifier is also known as a:

Accepted Answer

Source follower

Answer

Emitter follower

Answer

Common-collector amplifier