Question 1

The JFET uses a positive drain supply voltage VDD).

Accepted Answer

A)  n-channel 
B)  p-channel 
A)  n-channel 
B)  p-channel A

Question 2

Which of the following is usually used to control the channel width of a given JFET?

Accepted Answer

A)  VS 
B)  VGS 
C)  The operating frequency 
D)  ID 
A)  VS 
B)  VGS 
C)  The operating frequency 
D)  ID B

Question 3

The value of VDS that causes ID to reach its maximum value at a constant value of VGS is called

Accepted Answer

A)  VDmax). 
B)  pinchoff voltage. 
C)  VDSS. 
D)  None of these is correct. 
A)  VDmax). 
B)  pinchoff voltage. 
C)  VDSS. 
D)  None of these is correct. B

Question 4

The value of gm is always the value of gm0 for a given JFET.

Accepted Answer

A)  less than 
B)  equal to 
C)  less than or equal to 
D)  greater than 
A)  less than 
B)  equal to 
C)  less than or equal to 
D)  greater than

Question 5

In a JFET amplifier, VGS = -5 V, IG = 0 mA, and ID = IS = 5mA. Which of the following statements is true?

Accepted Answer

A)  The gate terminal of the JFET is probably open. 
B)  The gate-source junction of the JFET is probably shorted. 
C)  The drain terminal of the JFET is probably open. 
D)  The readings do not indicate that any problem exists. 
A)  The gate terminal of the JFET is probably open. 
B)  The gate-source junction of the JFET is probably shorted. 
C)  The drain terminal of the JFET is probably open. 
D)  The readings do not indicate that any problem exists.

Question 6

One advantage of using a JFET rf amplifier over a BJT amplifier is

Accepted Answer

A)  high input impedance. 
B)  The JFET requires no signal input current. 
C)  The JFET is less susceptible to noise. 
D)  All of the above. 
A)  high input impedance. 
B)  The JFET requires no signal input current. 
C)  The JFET is less susceptible to noise. 
D)  All of the above.

Question 7

A JFET has values of IDSS = 10 mA and VGSoff) = -5 V. What is the value of ID at VGS = -3 V?

Accepted Answer

A)  1.6 mA 
B)  3.6 mA 
C)  25.6 mA 
D)  4 mA 
A)  1.6 mA 
B)  3.6 mA 
C)  25.6 mA 
D)  4 mA

Question 8

As the channel width of a JFET decreases, the source-to-drain resistance of the device

Accepted Answer

A)  increases. 
B)  decreases. 
A)  increases. 
B)  decreases.

Question 9

A JFET has the following ratings: VGSoff) = -2 V to -5 V and IDSS = 4 mA to 12 mA. The device is being used in a gate bias circuit with a gate supply voltage of VGG = -1 V. What is the difference between the minimum and maximum values of ID for the circuit?

Accepted Answer

A)  7.68 mA 
B)  9.6 mA 
C)  6.68 mA 
D)  8.6 mA 
A)  7.68 mA 
B)  9.6 mA 
C)  6.68 mA 
D)  8.6 mA

Question 10

Which of the JFET biasing circuits listed below provides the best Q-point stability?

Accepted Answer

A)  Gate-bias 
B)  Self-bias 
C)  Voltage-divider bias 
D)  Current-source bias 
A)  Gate-bias 
B)  Self-bias 
C)  Voltage-divider bias 
D)  Current-source bias

Question 11

A given JFET has values of Vp = +10 V and IDSS = 8 mA. What is the value of VGSoff) for the device?

Accepted Answer

A)  +10 V 
B)  -10 V 
C)  -5 V 
D)  Cannot be determined from the information given. 
A)  +10 V 
B)  -10 V 
C)  -5 V 
D)  Cannot be determined from the information given.

Question 12

-The amplifier has high input impedance, low output impedance, and low-voltage gain.

Accepted Answer

A)  common-gate 
B)  common-drain 
C)  common-source 
A)  common-gate 
B)  common-drain 
C)  common-source

Question 13

A JFET has values of IDSS = 12 mA and VGSoff) = -4 V. What is the value of ID at VGS = -8 V?

Accepted Answer

A)  12 mA 
B)  0 mA 
C)  4 mA 
D)  2 mA 
A)  12 mA 
B)  0 mA 
C)  4 mA 
D)  2 mA

Question 14

-The JFET in Figure  has the following ratings: VGSoff) = -5 V and gm0 = 4000 μS. What is the value of Av for the circuit?

Accepted Answer

A)  1.2 
B)  1.47 
C)  0.4 
D)  0.9 
A)  1.2 
B)  1.47 
C)  0.4 
D)  0.9

Question 15

A given JFET has values of gm0 = 1000 μS and VGSoff) = -6 V. The device is being used in a common-source amplifier with values of RD = 2.2 kΩ, RL = 10 kΩ, and VGS = -1V. What is the value of Av for the circuit?

Accepted Answer

A)  1.5 
B)  2.2 
C)  10 
D)  Cannot be determined with the information given. 
A)  1.5 
B)  2.2 
C)  10 
D)  Cannot be determined with the information given.

Question 16

-The JFET in Figure has the following ratings: VGSoff) = -2 V to -10 V, gm0 = 1000 μS to 1600 μS. What is the approximate input impedance of the circuit?

Accepted Answer

A)  179 kΩ 
B)  1 MΩ 
C)  848 kΩ 
D)  922 kΩ 
A)  179 kΩ 
B)  1 MΩ 
C)  848 kΩ 
D)  922 kΩ

Question 17

The terminal is the JFET counterpart of the BJT base terminal.

Accepted Answer

A)  gate 
B)  drain 
C)  source 
A)  gate 
B)  drain 
C)  source

Question 18

A JFET has the following ratings: VGSoff) = -2 V to -5 V and IDSS = 4 mA to 12 mA. The device is being used in a voltage divider circuit. When the load line is plotted, it is found that the VGS for the circuit has a range of -1 V to -3.5 V. What are the corresponding Qmax) values?

Accepted Answer

A)  VGSQ = -1 V, IDQ = 7.68 mA 
B)  VGSQ = -3.5 V, IDQ = 1.1 mA 
C)  VGSQ = -1 V, IDQ = 1 mA 
D)  Cannot be determined with the information given. 
A)  VGSQ = -1 V, IDQ = 7.68 mA 
B)  VGSQ = -3.5 V, IDQ = 1.1 mA 
C)  VGSQ = -1 V, IDQ = 1 mA 
D)  Cannot be determined with the information given.

Question 19

A given JFET has values of gm0 = 1200 μS and VGSoff) = -4 V. What is the value of gm for the device at VGS = -2 V?

Accepted Answer

A)  600 μS 
B)  1200 μS 
C)  300 μS 
D)  Cannot be determined with the information given. 
A)  600 μS 
B)  1200 μS 
C)  300 μS 
D)  Cannot be determined with the information given.

Question 20

The terminal is the JFET counterpart of the BJT collector terminal.

Accepted Answer

A)  gate 
B)  drain 
C)  source 
A)  gate 
B)  drain 
C)  source

Exam 12: Field-Effect Transistors

The JFET uses a positive drain supply voltage VDD).

Which of the following is usually used to control the channel width of a given JFET?

The value of VDS that causes ID to reach its maximum value at a constant value of VGS is called

The value of gm is always the value of gm0 for a given JFET.

In a JFET amplifier, VGS = -5 V, IG = 0 mA, and ID = IS = 5mA. Which of the following statements is true?

One advantage of using a JFET rf amplifier over a BJT amplifier is

A JFET has values of IDSS = 10 mA and VGSoff) = -5 V. What is the value of ID at VGS = -3 V?

As the channel width of a JFET decreases, the source-to-drain resistance of the device

A JFET has the following ratings: VGSoff) = -2 V to -5 V and IDSS = 4 mA to 12 mA. The device is being used in a gate bias circuit with a gate supply voltage of VGG = -1 V. What is the difference between the minimum and maximum values of ID for the circuit?

Which of the JFET biasing circuits listed below provides the best Q-point stability?

A given JFET has values of Vp = +10 V and IDSS = 8 mA. What is the value of VGSoff) for the device?

-The amplifier has high input impedance, low output impedance, and low-voltage gain.

A JFET has values of IDSS = 12 mA and VGSoff) = -4 V. What is the value of ID at VGS = -8 V?

-The JFET in Figure has the following ratings: VGSoff) = -5 V and gm0 = 4000 μS. What is the value of Av for the circuit?

A given JFET has values of gm0 = 1000 μS and VGSoff) = -6 V. The device is being used in a common-source amplifier with values of RD = 2.2 kΩ, RL = 10 kΩ, and VGS = -1V. What is the value of Av for the circuit?

-The JFET in Figure has the following ratings: VGSoff) = -2 V to -10 V, gm0 = 1000 μS to 1600 μS. What is the approximate input impedance of the circuit?

The terminal is the JFET counterpart of the BJT base terminal.

A JFET has the following ratings: VGSoff) = -2 V to -5 V and IDSS = 4 mA to 12 mA. The device is being used in a voltage divider circuit. When the load line is plotted, it is found that the VGS for the circuit has a range of -1 V to -3.5 V. What are the corresponding Qmax) values?

A given JFET has values of gm0 = 1200 μS and VGSoff) = -4 V. What is the value of gm for the device at VGS = -2 V?

The terminal is the JFET counterpart of the BJT collector terminal.

Fundamental Solid-State Principles

Diodes

Common Diode Applications: Basic Power Supply Circuits

Common Diode Applications: Clippers, Clampers, Voltage Multipliers, and Displays

Special Applications Diodes

Bipolar Junction Transistors

DC Biasing Circuits

Introduction to Amplifiers

Common-Emitter Amplifiers

Other BJT Amplifiers

Power Amplifiers

Mosfets

Amplifier Frequency Response

Operational Amplifiers

Additional Op-Amp Applications

Tuned Amplifiers

Oscillators

Solid-State Switching Circuits

Thyristors and Optoelectronics Devices

Discrete and Integrated Voltage Regulators

Filters