FET Characteristics: Interactive Learning Quizzes for Electronics II

Question 1

Which parameter is NOT characteristic of a FET?

Accepted Answer

Current gain

Answer

Threshold voltage

Answer

Transconductance

Answer

Transresistance

Question 2

What type of FET has an insulated gate?

Accepted Answer

MOSFET

Answer

JFET

Answer

Depletion-mode FET

Answer

Enhancement-mode FET

Question 3

How does transconductance (gm) relate to FET channel width (W)?

Accepted Answer

gm is directly proportional to W

Answer

gm is inversely proportional to W

Answer

gm is independent of W

Answer

gm is exponentially proportional to W

Question 4

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

Accepted Answer

Prevent oscillation

Answer

Reduce voltage gain

Answer

Stabilize operating point

Answer

Increase input impedance

Question 5

What is the maximum drain current (IDSS) in a JFET?

Accepted Answer

Drain current when VGS = 0 V

Answer

Drain current when VGS = VGS(off)

Answer

Drain current when VDS = VDD

Answer

Drain current when VDS = VGS

Question 6

How does increasing the drain-to-source voltage (VDS) affect the transconductance (gm) of a MOSFET?

Accepted Answer

gm decreases

Answer

gm increases

Answer

gm remains constant

Answer

gm is unpredictable

Question 7

In a FET amplifier circuit, which parameter is the primary determinant of voltage gain?

Accepted Answer

Transconductance

Answer

Gate-Source Voltage

Answer

Drain-Source Current

Answer

Threshold Voltage

Question 8

When designing biasing circuits for FETs, what are the key considerations and objectives? Provide an illustrative example of how to bias a JFET and explain the rationale behind your design choices.

Accepted Answer

Correct. When designing FET biasing circuits, you should consider the desired operating point, circuit stability, and protection against excessive current or voltage.

Answer

Incorrect. FET biasing circuits only require a voltage source and a resistor.

Answer

Incorrect. FETs do not require biasing circuits; they can operate without them.

Answer

Incorrect. FET biasing circuits solely involve voltage sources.

Question 9

**Analyze the differences between MOSFETs and JFETs based on their input impedance, transconductance, and susceptibility to damage. Discuss the benefits and drawbacks of each type, providing examples of their typical applications.

Accepted Answer

MOSFETs exhibit higher input impedance compared to JFETs, making them more appropriate for circuits with high impedance.

Accepted Answer

JFETs have lower transconductance than MOSFETs, which limits their use in high-frequency applications.

Accepted Answer

MOSFETs are more vulnerable to damage from electrostatic discharge than JFETs, making them less suitable for applications where electrostatic discharge is a concern.

Question 10

In a JFET, the gate terminal is:

Accepted Answer

Reverse-biased with respect to the source

Answer

Forward-biased with respect to the drain

Answer

Forward-biased with respect to the source

Answer

Reverse-biased with respect to the drain

Question 11

The threshold voltage of a FET is:

Accepted Answer

The gate-source voltage at which the channel begins to conduct

Answer

The drain-source voltage at which the channel is fully on

Answer

The gate-source voltage at which the channel is fully off

Question 12

Which of the following is a key application of FETs?

Accepted Answer

Amplification and switching

Answer

Voltage regulation solely

Answer

Energy storage

Answer

Current sensing exclusively

Question 13

In a common-source FET amplifier:

Accepted Answer

The input signal is applied to the gate, and the output signal is taken from the drain

Answer

The input signal is applied to the source, and the output signal is taken from the gate

Answer

The input signal is applied to the source, and the output signal is taken from the drain

Answer

The input signal is applied to the gate, and the output signal is taken from the source

Question 14

In a JFET, which of the following statements accurately describes the relationship between drain-source current (ID) and gate-source voltage (VGS)?

Accepted Answer

ID is controlled by VGS

Answer

ID is controlled by drain-source voltage (VDS)

Answer

ID is directly proportional to VGS

Answer

ID is independent of VGS

Question 15

What is the definition of transconductance (gm) in a MOSFET?

Accepted Answer

The ratio of change in drain-source current (ID) to the change in gate-source voltage (VGS)

Answer

The ratio of change in gate-source voltage (VGS) to the change in ID

Answer

The ratio of change in drain-source voltage (VDS) to the change in ID

Question 16

In a JFET, which region of operation is utilized when the device functions as a variable resistor?

Accepted Answer

Ohmic region

Answer

Cutoff region

Answer

Saturation region

Answer

Breakdown region

Question 17

Which of the following parameters does NOT influence the drain-source resistance (RDS) of a MOSFET?

Accepted Answer

Gate-source voltage

Answer

Channel width

Answer

Drain-source current

Answer

Channel length

Question 18

What is a defining characteristic of the saturation region in a MOSFET?

Accepted Answer

Constant drain-source current with increasing drain-source voltage

Answer

Zero drain-source current

Answer

Constant gate-source voltage with increasing drain-source current

Question 19

Explain the phenomenon known as the body effect in MOSFETs.

Accepted Answer

Change in threshold voltage due to the voltage applied to the substrate

Answer

Change in transconductance due to the gate-source voltage

Answer

Change in drain-source current due to the drain-source voltage

Question 20

What is the primary distinction between a depletion-mode and an enhancement-mode MOSFET?

Accepted Answer

Depletion-mode MOSFETs possess a conducting channel at zero gate-source voltage, while enhancement-mode MOSFETs require a gate-source voltage above threshold to form a channel.

Answer

Depletion-mode MOSFETs exhibit a higher threshold voltage compared to enhancement-mode MOSFETs.

Question 21

Which fundamental characteristic is a hallmark of MOSFETs?

Accepted Answer

High input impedance

Answer

Negligible transconductance

Answer

High threshold voltage

Answer

Low output impedance

Question 22

In a JFET, what is the role of the gate-source voltage (Vgs)?

Accepted Answer

To control the extent of the depletion region

Answer

To establish proper biasing

Answer

To limit the flow of current

Answer

To provide a source of electrons

Question 23

Which mathematical expression represents the transconductance (gm) of a MOSFET?

Accepted Answer

gm = dIds / dVgs

Answer

gm = Ids / Vds

Answer

gm = Vds / Ids

Answer

gm = dVgs / dIds

Question 24

Describe the threshold voltage (Vth) of a FET.

Accepted Answer

The gate-source voltage at which a significant amount of current starts flowing

Answer

The gate-source voltage at which the FET turns off

Answer

The drain-source voltage at which the FET enters saturation

Question 25

Which FET operating region is characterized by a constant drain current?

Accepted Answer

Saturation region

Answer

Cut-off region

Answer

Ohmic region

Answer

Triode region

Question 26

In the triode region of a MOSFET, what is the effect of increasing the gate-source voltage (Vgs)?

Accepted Answer

Increases drain current

Answer

Decreases drain current

Answer

Increases transconductance

Question 27

What is the main function of a depletion-mode MOSFET?

Accepted Answer

To operate as a normally-on switch

Answer

To amplify voltage signals

Answer

To regulate current flow

Answer

To provide high input impedance

Question 28

The transconductance of a JFET is primarily influenced by

Accepted Answer

Gate-source voltage

Answer

Drain-source voltage

Answer

Source-gate voltage

Answer

Drain-gate voltage

Question 29

The threshold voltage of a MOSFET is defined as

Accepted Answer

The gate-source voltage at which the channel begins to conduct

Answer

The drain-source voltage at which the channel pinches off

Answer

The source-gate voltage at which the channel becomes fully depleted

Question 30

The output resistance of a FET is defined as the ratio of

Accepted Answer

Drain-source voltage to drain current

Answer

Gate-source voltage to drain current

Answer

Drain current to gate-source voltage

Answer

Gate-source voltage to drain-source voltage

Question 31

Which of the following applications is generally not considered suitable for a FET?

Accepted Answer

Power amplifiers

Answer

Analog switches

Answer

Small-signal amplifiers

Answer

Digital logic gates

Question 32

Identify the characteristic that is NOT typically associated with a MOSFET:

Accepted Answer

Low input impedance

Answer

High transconductance

Answer

High voltage gain

Answer

Low noise

Question 33

The transconductance of a FET is defined as the ratio of:

Accepted Answer

Output current to input voltage

Answer

Input current to output voltage

Answer

Output voltage to input current

Answer

Input voltage to output current

Question 34

The threshold voltage of a JFET is the gate-to-source voltage at which:

Accepted Answer

The channel begins to conduct

Answer

The channel is fully depleted

Answer

The JFET enters saturation

Question 35

MOSFETs are known for their:

Accepted Answer

Very high input resistance

Answer

Low input resistance

Answer

Moderate input resistance

Question 36

Compared to JFETs, MOSFETs offer:

Accepted Answer

A wider gate voltage range

Answer

A narrower gate voltage range

Answer

Equivalent gate voltage range

Question 37

The output characteristics of a FET are primarily influenced by:

Accepted Answer

Drain-source voltage and gate-source voltage

Answer

Temperature only

Answer

Gate-source voltage only

Answer

Drain-source voltage only

Question 38

A potential disadvantage associated with FETs is their:

Accepted Answer

Higher cost compared to bipolar transistors

Answer

Higher efficiency

Answer

Lower noise performance

Question 39

The depletion region in a JFET is primarily formed due to:

Accepted Answer

Reverse bias between the gate-channel PN junction

Answer

Reverse bias between the source-drain PN junction

Answer

Forward bias between the gate-channel PN junction

Question 40

The transconductance of a JFET is:

Accepted Answer

Directly proportional to the square root of the drain current

Answer

Independent of the drain-source voltage

Answer

Proportional to the gate-source voltage

Question 41

The threshold voltage of a MOSFET is:

Accepted Answer

The gate-source voltage at which the drain current starts to flow significantly

Answer

The gate-source voltage at which the transconductance is maximum

Answer

The drain-source voltage at which the drain current saturates

Question 42

Which of the following is NOT a characteristic of a depletion-mode JFET?

Accepted Answer

It requires a positive gate-source voltage to turn on

Answer

It has a high input impedance

Answer

It has a low output impedance

Question 43

FETs are commonly used in:

Accepted Answer

Both amplifiers and switches

Answer

Microprocessors only

Answer

Sensors only

Answer

Power supplies only

Question 44

For n-channel JFETs, the gate-source voltage is typically:

Accepted Answer

Negative

Answer

Positive

Answer

Zero

Question 45

The drain-source saturation voltage of a MOSFET is:

Accepted Answer

Approximately equal to the overdrive voltage when the device is in saturation

Answer

Zero when the gate-source voltage is below the threshold voltage

Answer

Proportional to the drain current

Answer

Independent of the gate-source voltage

Question 46

Which of the following is a type of FET?

Accepted Answer

MESFET

Answer

Diode

Answer

Resistor

Answer

BJT

Question 47

Which of the following devices is NOT a type of Field-Effect Transistor (FET)?

Accepted Answer

Bipolar Junction Transistor (BJT)

Answer

Insulated Gate Bipolar Transistor (IGBT)

Answer

Junction FET (JFET)

Answer

Metal-Oxide-Semiconductor FET (MOSFET)

Question 48

In the saturation region, the current-voltage characteristic of a FET can be best described as:

Accepted Answer

Nearly constant current, independent of drain-source voltage

Answer

A linear relationship between current and voltage

Answer

An exponential increase in current with voltage

Answer

A parabolic relationship between current and voltage

Question 49

Transconductance (g_m) in a FET is defined as the:

Accepted Answer

Change in drain current (ΔI_D) divided by the change in gate-source voltage (ΔV_GS), at a constant drain-source voltage

Answer

Change in gate current per unit change in drain-source voltage

Answer

Ratio of drain current to gate-source voltage

Answer

Change in drain-source voltage per unit change in gate current

Question 50

The threshold voltage (V_th) of a FET is the:

Accepted Answer

Gate-source voltage at which a conductive channel forms between the source and drain

Answer

Gate-source voltage at which the channel is entirely depleted of charge carriers

Answer

Drain-source voltage required for current flow between source and drain

Answer

Minimum voltage required to turn the FET on

Question 51

A depletion-mode FET is characterized by being:

Accepted Answer

Normally ON: A channel exists, and current flows, with zero gate-source voltage

Answer

Unidirectional: Allowing current flow in only one direction

Answer

Bipolar: Utilizing both majority and minority carriers for current conduction

Answer

Normally OFF: Requiring a gate-source voltage to create a conductive channel

Question 52

The pinch-off voltage (V_p) in a JFET refers to the:

Accepted Answer

Gate-source voltage at which the conductive channel is completely constricted, reducing current flow to a minimum

Answer

Maximum drain-source voltage before breakdown occurs

Answer

Drain-source voltage required to initiate current flow between source and drain

Answer

Gate-source voltage at which a conductive channel begins to form

Question 53

When analyzing the small-signal behavior of a FET, which parameter is considered most important?

Accepted Answer

Transconductance (g_m)

Answer

Drain-source saturation current (I_DSS)

Answer

Pinch-off voltage (V_p)

Answer

Threshold voltage (V_th)

Question 54

Which statement accurately describes the output resistance of a FET operating in the saturation region?

Accepted Answer

Very high, approximating an ideal current source

Answer

Close to zero, behaving like a short circuit

Answer

Highly dependent on the gate-source voltage

Answer

Equal to the resistance of the conductive channel

Question 55

Field-Effect Transistors (FETs) are widely utilized in electronic circuits primarily due to their:

Accepted Answer

High input impedance, voltage-controlled current, and low power consumption

Answer

Linear output characteristics, high noise immunity, and compatibility with bipolar technologies

Answer

High current gain, low voltage operation, and high power handling capability

Answer

Low input impedance, current-controlled voltage output, and high switching speeds