# Multiple Choice Questions and Answers on FET

**Multiple Choice Questions and Answers on FET ( Field Effect Transistors )**

In addition to reading the questions and answers on my site, I would suggest you to check the following, on amazon, as well:

**Question Bank in Electronics & Communication Engineering by Prem R Chadha****A Handbook on Electronics Engineering – Illustrated Formulae & Key Theory Concepts**

**Q1. A JFET has three terminals, namely …………**

- cathode, anode, grid
- emitter, base, collector
- source, gate, drain
- none of the above

**Answer : 3**

**Q2. A JFET is similar in operation to …………. valve**

- diode
- pentode
- triode
- tetrode

**Answer : 2**

**Q3. A JFET is also called …………… transistor**

- unipolar
- bipolar
- unijunction
- none of the above

**Answer : 1**

**Q4. A JFET is a ………… driven device**

- current
- voltage
- both current and voltage
- none of the above

**Answer : 2**

**Q5. The gate of a JFET is ………… biased**

- reverse
- forward
- reverse as well as forward
- none of the above

**Answer : 1**

**Q6. The input impedance of a JFET is …………. that of an ordinary transistor**

- equal to
- less than
- more than
- none of the above

**Answer : 3**

**Q7. In a p-channel JFET, the charge carriers are …………..**

- electrons
- holes
- both electrons and holes
- none of the above

**Answer : 2**

**Q8. When drain voltage equals the pinch-off-voltage, then drain current …………. with the increase in drain voltage**

- decreases
- increases
- remains constant
- none of the above

**Answer : 3**

**Q9. If the reverse bias on the gate of a JFET is increased, then width of the conducting channel …………..**

- is decreased
- is increased
- remains the same
- none of the above

**Answer : 1**

**Q10. A MOSFET has …………… terminals**

- two
- five
- four
- three

**Answer : 4**

**Q11. A MOSFET can be operated with ……………..**

- negative gate voltage only
- positive gate voltage only
- positive as well as negative gate voltage
- none of the above

**Answer : 3**

**Q12. A JFET has ……….. power gain**

- small
- very high
- very small
- none of the above

**Answer : 2**

**Q13. The input control parameter of a JFET is ……………**

- gate voltage
- source voltage
- drain voltage
- gate current

**Answer : 1**

**Q14. A common base configuration of a pnp transistor is analogous to ………… of a JFET**

- common source configuration
- common drain configuration
- common gate configuration
- none of the above

**Answer : 3**

**Q15. A JFET has high input impedance because …………**

- it is made of semiconductor material
- input is reverse biased
- of impurity atoms
- none of the above

**Answer : 2**

**Q16. In a JFET, when drain voltage is equal to pinch-off voltage, the depletion layers ………**

- almost touch each other
- have large gap
- have moderate gap
- none of the above

**Answer : 1**

**Q17. In a JFET, I _{DSS} is known as …………..**

- drain to source current
- drain to source current with gate shorted
- drain to source current with gate open
- none of the above

**Answer : 2**

**Q18. The two important advantages of a JFET are …………..**

- high input impedance and square-law property
- inexpensive and high output impedance
- low input impedance and high output impedance
- none of the above

**Answer : 1**

**Q19. …………. has the lowest noise-level**

- triode
- ordinary trnsistor
- tetrode
- JFET

**Answer : 4**

**Q20. A MOSFET is sometimes called ………. JFET**

- many gate
- open gate
- insulated gate
- shorted gate

**Answer : 3**

**Q21. Which of the following devices has the highest input impedance?**

- JFET
- MOSFET
- Crystal diode
- ordinary transistor

**Answer : 2**

**Q22. A MOSFET uses the electric field of a ………. to control the channel current**

- capacitor
- battery
- generator
- none of the above

**Answer : 1**

**Q23. The pinch-off voltage in a JFET is analogous to ………. voltage in a vacuum tube**

- anode
- cathode
- grid cut off
- none of the above

**Answer : 3**

**Q24. This question will be available soon**

**Q25. In class A operation, the input circuit of a JFET is ………. biased**

- forward
- reverse
- not
- none of the above

**Answer : 2**

**Q26. If the gate of a JFET is made less negative, the width of the conducting channel……….**

- remains the same
- is decreased
- is increased
- none of the above

**Answer : 3**

**Q27. The pinch-off voltage of a JFET is about ……….**

- 5 V
- 0.6 V
- 15 V
- 25 V

**Answer : 1**

**Q28. The input impedance of a MOSFET is of the order of ………..**

- Ω
- a few hundred Ω
- kΩ
- several MΩ

**Answer : 4**

**Q29. The gate voltage in a JFET at which drain current becomes zero is called ……….. voltage**

- saturation
- pinch-off
- active
- cut-off

**Answer : 2**

**Q30. This question will be available soon**

**Q31. In a FET, there are ……….. pn junctions at the sides**

- three
- four
- five
- two

**Answer : 4**

**Q32. The transconductance of a JFET ranges from ……………..**

- 100 to 500 mA/V
- 500 to 1000 mA/V
- 0.5 to 30 mA/V
- above 1000 mA/V

**Answer : 3**

**Q33. The source terminal of a JEFT corresponds to ………….. of a vacuum tube**

- plate
- cathode
- grid
- none of the above

**Answer : 2**

**Q34. The output characteristics of a JFET closely resemble the output characteristics of a ………. valve**

- pentode
- tetrode
- triode
- diode

**Answer : 1**

**Q35. If the cross-sectional area of the channel in n-channel JEFT increases, the drain current ……….**

- is increased
- is decreased
- remains the same
- none of the above

**Answer : 1**

**Q36. The channel of a JFET is between the …………….**

- gate and drain
- drain and source
- gate and source
- input and output

**Answer : 2**

**Q37. For V _{GS} = 0 V, the drain current becomes constant when V_{DS} exceeds ………**

- cut off
- V
_{DD} - V
_{P} - o V

**Answer : 3**

**Q38. A certain JFET data sheet gives V _{GS(off)} = -4 V. The pinch-off voltage V_{p} is ……..**

- +4 V
- -4 V
- dependent on V
_{GS} - data insufficient

**Answer : 1**

**Q39. The constant-current region of a JFET lies between**

- cut off and saturation
- cut off and pinch-off
- o and I
_{DSS} - pinch-off and breakdown

**Answer : 4**

**Q40. At cut-off, the JFET channel is ……….**

- at its widest point
- completely closed by the depletion region
- extremely narrow
- reverse baised

**Answer : 2**

**Q41. A MOSFET differs from a JFET mainly because ………………**

- of power rating
- the MOSFET has two gates
- the JFET has a pn junction
- none of the above

**Answer : 3**

**Q42. A certain D-MOSFET is biased at V _{GS} = 0 V. Its data sheet specifies I_{DSS }= 20mA and V_{GS(off)} = -5 V. The value of the drain current is …………**

- 20 mA
- 0 mA
- 40 mA
- 10 mA

**Answer : 1**

**Q43. A n-channel D-MOSFET with a positive V _{GS} is operating in …………**

- the depletion-mode
- the enhancement-mode
- cut off
- saturation

**Answer : 2**

**Q44. A certain p-channel E-MOSFET has V _{GS(th)} = -2V. If V_{GS}= 0V, the drain current is ……….**

- 0 mA
- I
_{D(on)} - maximum
- I
_{DSS}

**Answer : 1**

**Q45. In a common-source JFET amplifier, the output voltage is …………………**

- 180
^{o}out of phase with the input - in phase with the input
- 90
^{o}out of phase with the input - taken at the source

**Answer : 1**

**Q46. In a certain common-source D-MOSFET amplifier, V _{ds} =3.2 V r.m. and V_{gs} = 280 mV r.m.s. The voltage gain is …………**

- 1
- 11.4
- 8.75
- 3.2

**Answer : 2**

**Q47. In a certain CS JFET amplifier, R _{D}= 1kΩ , R_{S}= 560 Ω , V_{DD}=10V and g_{m}= 4500 μS. If the source resistor is completely bypassed, the voltage gain is …………**

- 450
- 45
- 2.52
- 4.5

**Answer : 4**

**Q48. A certain common-source JFET has a voltage gain of 10. If the source bypass capacitor is removed, ……………….**

- the voltage gain will increase
- the transconductance will increase
- the voltage gain will decrease
- the Q-point will shift

**Answer : 3**

**Q49. A CS JFET amplifier has a load resistance of 10 kΩ , R _{D}= 820Ω . If g_{m}= 5mS and V_{in}= 500 mV, the output signal voltage is ………..**

- 2.05 V
- 25 V
- 0.5 V
- 1.89 V

**Answer : 4**

**Q50. If load resistance in the above question (Q.49) is removed, the output voltage will …………**

- increase
- decrease
- stay the same
- be zero

**Answer : 1**

**Q.51. When not in use, MOSFET pins are kept at the same potential through the use of …………**

- shipping foil
- nonconductive foam
- conductive foam
- a wrist strap

**Answer: 3**

**Q.52. D-MOSFETs are sometimes used in series to construct a cascode high-frequency amplifier to overcome the loss of …………..**

- low output impedance
- capacitive reactance
- high input impedance
- inductive reactance

**Answer: 3**

**Q.53. A “U” shaped, opposite-polarity material built near a JFET-channel center is called the ……….**

- gate
- block
- drain
- heat sink

**Answer: 1**

**Q.54. When testing an n-channel D-MOSFET, resistance G to D = , resistance G to S = , resistance D to SS = and 500 , depending on the polarity of the ohmmeter, and resistance D to S = 500 . What is wrong?**

- short D to S
- open G to D
- open D to SS
- nothing

**Answer: 4**

**Q.55. In the constant-current region, how will the I _{DS} change in an n-channel JFET?**

- As V
_{GS}decreases I_{D}decreases. - As V
_{GS}increases I_{D}increases - As V
_{GS}decreases I_{D}remains constant. - As V
_{GS}increases I_{D}remains constant.

**Answer: 1**

**Q.56. I _{DSS} can be defined as ………**

- the minimum possible drain current
- the maximum possible current with V
_{GS}held at –4 V - the maximum possible current with V
_{GS}held at 0 V - the maximum drain current with the source shorted

**Answer: 3**

**Q.57. The input impedance of a common-gate configured JFET is …………**

- very low
- low
- high
- very high

**Answer: 1**

**Q.58. A very simple bias for a D-MOSFET is called ……..**

- self biasing
- gate biasing
- zero biasing
- voltage-divider biasing

**Answer: 3**

**Q.59. With the E-MOSFET, when gate input voltage is zero, drain current is …..**

- at saturation
- zero
- I
_{DSS} - widening the channel

**Answer: 2**

**Q.60. With a 30-volt V _{DD}, and an 8-kilohm drain resistor, what is the E-MOSFET Q point voltage, with I_{D} = 3 mA?**

- 6 V
- 10 V
- 24 V
- 30 V

**Answer: 1**

**Q.61. When an input signal reduces the channel size, the process is called …….**

- enhancement
- substrate connecting
- gate charge
- depletion

**Answer: 4**

**Q.62. Which JFET configuration would connect a high-resistance signal source to a low-resistance load ?**

- source follower
- common-source
- common-drain
- common-gate

**Answer: 1**

**Q.63. When V _{GS} = 0 V, a JFET is……….**

- saturated
- an analog device
- an open switch
- an open switch

**Answer: 1**

**Q.64. The electrons flow through a p-channel JFET from ……….. to …………..**

- from source to drain
- from source to gate
- from drain to gate
- from drain to source

**Answer: 4**

**Q.65. When applied input voltage varies the resistance of a channel, the result is called…………..**

- saturization
- polarization
- cutoff
- field effect

**Answer: 4**

**Q.66. When is a vertical channel E-MOSFET used?**

- for high frequencies
- for high voltages
- for high currents
- for high resistances

**Answer: 3**

**Q.67. When the JFET is no longer able to control the current, this point is called the …………**

- breakdown region
- depletion region
- saturation point
- pinch-off region

**Answer: 1**

**Q.68. With a JFET, a ratio of output current change against an input voltage change is called as ………..**

- transconductance
- siemens
- resistivity
- gain

**Answer: 1**

**Q.69. Which type of JFET bias requires a negative supply voltage?**

- feedback
- source
- gate
- voltage divider

**Answer: 3**

**Q.70. How will a D-MOSFET input impedance change with signal frequency?**

- As frequency increases input impedance increases.
- As frequency increases input impedance is constant.’
- As frequency decreases input impedance increases.
- As frequency decreases input impedance is constant.

**Answer: 3**

**Q.71. The type of bias most often used with E-MOSFET circuits is………….**

- constant current
- drain-feedback
- voltage-divider
- zero biasing

**Answer: 2**

**Q.72. The transconductance curve of a JFET is a graph of …………… vs ……….**

- I
_{S}versus V_{DS} - I
_{C}versus V_{CE} - I
_{D}versus V_{GS} - I
_{D}× R_{DS}

**Answer: 3**

**Q.73. The common-source JFET amplifier has ………..**

- a very high input impedance and a relatively low voltage gain
- a high input impedance and a very high voltage gain
- a high input impedance and a voltage gain less than 1
- no voltage gain

**Answer: 1**

**Q.74. The overall input capacitance of a dual-gate D-MOSFET is lower because the devices are usually connected ………..**

- in parallel
- with separate insulation
- with separate inputs
- in series

**Answer: 4**

**Q.75. Which component is considered to be an “OFF” devic.**

- transistor
- JFET
- D-MOSFET
- E-MOSFET

**Answer: 4**

**Q.76. In an n-channel JFET, what will happen at the pinch-off voltage?**

- the value of V
_{DS}at which further increases in V_{DS}will cause no further increase in I_{D} - the value of V
_{GS}at which further decreases in V_{GS}will cause no further increases in I_{D} - the value of V
_{DG}at which further decreases in V_{DG}will cause no further increases in I_{D} - the value of V
_{DS}at which further increases in V_{GS}will cause no further increases in I_{D}

**Answer: 1**

Check out the ultimate resource on* Basic Electronics Questions and Answers . *With hundreds of chapter-wise questions & answers on Basic Electronics, this is the most comprehensive question bank on the entire internet.

In addition to reading the questions and answers on my site, I would suggest you to check the following, on amazon, as well:

**Question Bank in Electronics & Communication Engineering by Prem R Chadha****A Handbook on Electronics Engineering – Illustrated Formulae & Key Theory Concepts**