MCQs in Junction Field Effect Transistor (JFETs)

Multiple Choice Questions in Junction Field Effect Transistor (JFETs) from the book Electronic Principles by Albert Malvino. Make sure to familiarize each and every questions

MCQs in  Junction Field Effect Transistor (JFETs)
This is the Multiple Choice Questions in Chapter 13: Junction Field Effect Transistor (JFETs) from the book Electronic Principles 7th Edition by Albert Malvino. If you are looking for a reviewer in Electronics Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Topic Outline

  • MCQs in Basic Ideas
  • MCQs in Drain Curves
  • MCQs in Transconductance Curve
  • MCQs in Biasing in the Ohmic Region
  • MCQs in biasing in the Active Region
  • MCQs in Transconductance
  • MCQs in JFET Amplifiers
  • MCQs in JFET Analog Switching
  • MCQs in Other JFET Applications
  • MCQs in JFET Testing

Begin and Good luck!

Choose the letter of the best answer in each questions.


  • a. Is a voltage-controlled device
  • b. Is a current-controlled device
  • c. Has a low input resistance
  • d. Has a very large voltage gain

2. A unipolar transistor uses

  • a. Both free electrons and holes
  • b. Only free electrons
  • c. Only holes
  • d. Either one or the other, but not both

3. The input impedance of a JFET

  • a. Approaches zero
  • b. Approaches one
  • c. Approaches infinity
  • d. Is impossible to predict

4. The gate controls

  • a. The width of the channel
  • b. The drain current
  • c. The proportional pinch-off voltage
  • d. All the above

5. The gate-source diode of a JFET should be

  • a. Forward-biased
  • b. Reverse-biased
  • c. Either forward- or reverse biased
  • d. None of the above

6. Compared to a bipolar transistor, the JFET has a much higher

  • a. Voltage gain
  • b. Input resistance
  • c. Supply voltage
  • d. Current

7. The pinch-off voltage has the same magnitude as the

  • a. Gate voltage
  • b. Drain-source voltage
  • c. Gate-source voltage
  • d. Gate-source cutoff voltage

8. When the drain saturation current is less than IDSS, a JFET acts like a

  • a. Bipolar transistor
  • b. Current source
  • c. Resistor
  • d. Battery

9. RDS equals pinch-off voltage divided by the

  • a. Drain current
  • b. Gate current
  • c. Ideal drain current
  • d. Drain current for zero gate voltage

10. The transconductance curve is

  • a. Linear
  • b. Similar to the graph of a resistor
  • c. Nonlinear
  • d. Like a single drain curve

11. The transconductance increases when the drain current approaches

  • a. 0
  • b. ID(sat)
  • c. IDSS
  • d. IS

12. A CS amplifier has a voltage gain of

  • a. gmrd
  • b. gmrs
  • c. gmrs/(l + gmrs)
  • d. gmrd/(l + gmrd)

13. A source follower has a voltage gain of

  • a. gmrd
  • b. gmrs
  • c. gmrs/(l + gmrs)
  • d. gmrd/(l + gmrd)

14. When the input signal is large, a source follower has

  • a. A voltage gain of less than one
  • b. A small distortion
  • c. A high input resistance
  • d. All of these

15. The input signal used with a JFET analog switch should be

  • a. Small
  • b. Large
  • c. A square wave
  • d. Chopped

16. A cascode amplifier has the advantage of

  • a. Large voltage gain
  • b. Low input capacitance
  • c. Low input impedance
  • d. Higher gm

17. VHF stands for frequencies from

  • a. 300 kHz to 3 MHz
  • b. 3 to 30 MHz
  • c. 30 to 300 MHz
  • d. 300 MHz to 3 GHz

18. When a JFET is cut off, the depletion layers are

  • a. Far apart
  • b. Close together
  • c. Touching
  • d. Conducting

19. When the gate voltage becomes more negative in an N channel JFET, the channel between the depletion layers

  • a. Shrinks
  • b. Expand
  • c. Conduct
  • d. Stop conducting

20. If a JFET has IDSS = 10 mA and VP = 2 V, then RDS equals

  • a. 200 ohm
  • b. 400 ohm
  • c. 1 kohm
  • d. 5 kohm

21. The easiest way to bias a JFET in the ohmic region is with

  • a. Voltage-divider bias
  • b. Self-bias
  • c. Gate bias
  • d. Source bias

22. Self-bias produces

  • a. Positive feedback
  • b. Negative feedback
  • c. Forward feedback
  • d. Reverse feedback

23. To get a negative gate-source voltage in a self-biased JFET circuit, you must have a

  • a. Voltage divider
  • b. Source resistor
  • c. Ground
  • d. Negative gate supply voltage

24. Transconductance is measured in

  • a. Ohms
  • b. Amperes
  • c. Volts
  • d. Mhos or Siemens

25. Transconductance indicates how effectively the input voltage controls the

  • a. Voltage gain
  • b. Input resistance
  • c. Supply voltage
  • d. Output current

Check your work.

Complete List of MCQs in Electronic Principles by Albert Malvino

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