# Floyd Self-test in Field-Effect Transistors (FETs)

(Last Updated On: March 1, 2021) This is the Self-test in Chapter 8: Field-Effect Transistors (FETs) from the book Electronic Devices Conventional Current Version, 9th edition by Thomas L. Floyd. If you are looking for a reviewer in Electronics Engineering this will definitely help you before taking the Board Exam.

#### Floyd Self-test Chapter 8 Topic Outline

• Floyd Self-test in Field-Effect Transistors (FETs)
• Floyd Self-test in JFET
• Floyd Self-test in JFET Characteristics and Parameters
• Floyd Self-test in JFET Biasing
• Floyd Self-test in The Ohmic Region
• Floyd Self-test in MOSFET
• Floyd Self-test in MOSFET Characteristics and Parameters
• Floyd Self-test in MOSFET Biasing
• Floyd Self-test in IGBT

If you are looking for the Multiple Choice Questions in Floyd’s Electronic Devices proceed to

#### Start Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. The JFET is

(a) a unipolar device

(b) a voltage-controlled device

(c) a current-controlled device

Solution:

2. The channel of a JFET is between the

(a) gate and drain

(b) drain and source

(c) gate and source

(d) input and output

Solution:

3. A JFET always operates with

(a) the gate-to-source pn junction reverse-biased

(b) the gate-to-source pn junction forward-biased

(c) the drain connected to ground

(d) the gate connected to the source

Solution:

4. For VGS = 0 V, the drain current becomes constant when VDS exceeds

(a) cutoff

(b) VDD

(c) VP

(d) 0 V

Solution:

5. The constant-current region of a FET lies between

(a) cutoff and saturation

(b) cutoff and pinch-off

(c) 0 and IDSS

(d) pinch-off and breakdown

Solution:

6. IDSS is

(a) the drain current with the source shorted

(b) the drain current at cutoff

(c) the maximum possible drain current

(d) the midpoint drain current

Solution:

7. Drain current in the constant-current region increases when

(a) the gate-to-source bias voltage decreases

(b) the gate-to-source bias voltage increases

(c) the drain-to-source voltage increases

(d) the drain-to-source voltage decreases

Solution:

8. In a certain FET circuit, VGS = 0 V, VDD = 15 V, IDSS = 15 mA, and RD = 470Ω. If RD is decreased to 330Ω, IDSS is

(a) 19.5 mA

(b) 10.5 mA

(c) 15 mA

(d) 1 mA

Solution:

9. At cutoff, the JFET channel is

(a) at its widest point

(b) completely closed by the depletion region

(c) extremely narrow

(d) reverse-biased

Solution:

10. A certain JFET datasheet gives The pinch-off voltage, VP,

(a) cannot be determined

(b) is –4V

(c) depends on VGS

(d) is +4V

Solution:

11. The JFET in Question 10

(a) is an n channel

(b) is a p channel

(c) can be either

Solution:

12. For a certain JFET, IGSS = 10 nA at VGS =10 V. The input resistance is

(a) 100 MΩ

(b) 1 MΩ

(c) 1000 MΩ

(d) 1000 mΩ

Solution:

13. For a certain p-channel JFET, VGS(off ) = 8 V. The value of VGS for an approximate midpoint bias is

(a) 4 V

(b) 0 V

(c) 1.25 V

(d) 2.34 V

Solution:

14. In a self-biased JFET, the gate is at

(a) a positive voltage

(b) 0 V

(c) a negative voltage

(d) ground

Solution:

15. The drain-to-source resistance in the ohmic region depends on

(a) VGS

(b) the Q-point values

(c) the slope of the curve at the Q-point

(d) all of these

Solution:

16. To be used as a variable resistor, a JFET must be

(a) an n-channel device

(b) a p-channel device

(c) biased in the ohmic region

(d) biased in saturation

Solution:

17. When a JFET is biased at the origin, the ac channel resistance is determined by

(a) the Q-point values

(b) VGS

(c) the transconductance

Solution:

18. A MOSFET differs from a JFET mainly because

(a) of the power rating

(b) the MOSFET has two gates

(c) the JFET has a pn junction

(d) MOSFETs do not have a physical channel

Solution:

19. A D-MOSFET operates in

(a) the depletion mode only

(b) the enhancement mode only

(c) the ohmic region only

(d) both the depletion and enhancement modes

Solution:

20. An n-channel D-MOSFET with a positive VGS is operating in

(a) the depletion mode

(b) the enhancement mode

(c) cutoff

(d) saturation

Solution:

21. A certain p-channel E-MOSFET has a If VGS = 0 V, the drain current is

(a) 0 A

(b) ID(on)

(c) maximum

(d) IDSS

Solution:

22. In an E-MOSFET, there is no drain current until VGS

(a) reaches VGS(th)

(b) is positive

(c) is negative

(d) equals 0 V

Solution:

23. All MOS devices are subject to damage from

(a) excessive heat

(b) electrostatic discharge

(c) excessive voltage

(d) all of these

Solution:

24. A certain D-MOSFET is biased at VGS = 0 V. Its datasheet specifies IDSS= 20 mA and the value of the drain current

(a) is 0 A

(b) cannot be determined

(c) is 20 mA

Solution:

25. An IGBT is generally used in

(a) low-power applications

(b) rf applications

(c) high-voltage applications

(d) low-current applications

Solution: