Deck 8: Field-Effect Transistors Fets

Question 1

Refer to b)in the figure above. If ID = 4 mA, the value of VGS is

A)0 V.
B)11.2 V.
C)8.8 V.
D)20 V.

Answer 1

A

Question 2

The types)of bias most often used with E- MOSFET circuits is

A)drain- feedback.
B)constant current.
C)voltage- divider.
D)Both A and C above.

Answer 2

D

Question 3

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

A)source resistor.
B)negative gate supply voltage.
C)voltage divider.
D)ground.

Answer 3

A

Question 4

The transconductance curve of a JFET is

A)linear.
B)hyperbolic.
C)nonlinear.
D)symmetrical.

Question 5

The transconductance curve of a JFET is a graph of

A)ID × RDS.
B)IC versus VCE.
C)IS versus VDS.
D)ID versus VGS.

Question 6

A V- MOSFET device operates in

A)a JFET mode.
B)the enhancement mode.
C)the depletion mode.
D)in either enhancement or depletion mode.

Question 7

The FET that has no physical channel is

A)the E- MOSFET.
B)the JFET.
C)the D- MOSFET.
D)None of the above.

Question 8

Special handling precautions should be taken when working with MOSFETs. Which of the following is not one of these precautions?

A)Workers handling MOSFET devices should not have grounding straps attached to their wrists.
B)All test equipment should be grounded.
C)MOSFET devices should have their leads shorted together for shipment and storage.
D)Never remove or insert MOSFET devices with the power on.

Question 9

IDSS can be defined as the

A)maximum possible current with the drain shorted to the source.
B)minimum possible drain current.
C)maximum current drain- to- source with a shorted gate.
D)maximum drain current with the source shorted.

Question 10

The pinch- off voltage has the same magnitude as the

A)gate voltage.
B)gate- source voltage.
C)gate- source cutoff voltage.
D)drain- source voltage.

Question 11

Refer to b)in the figure above. If ID = 2 mA, the value of VDS is

A)10 V.
B)20 V.
C)4.4 V.
D)15.6 V.

Question 12

One advantage of voltage- divider bias is that the dependency of drain current ID, on the range of Q- points is

A)reduced.
B)not affected.
C)increased.

Question 13

VDS equals pinch- off voltage divided by the

A)base current.
B)drain current for zero gate voltage.
C)gate current.
D)ideal drain current.

Question 14

A self- biased n-channel JFET has a VD = 8 V, VGS = - 5 V. The value of VDS is

A)- 5 V.
B)- 3 V.
C)8 V.
D)3 V.

Question 15

Refer to c)in the figure above. This symbol identifies

A)an n-channel E- MOSFET.
B)a p-channel D- MOSFET.
C)a p-channel E- MOSFET.
D)an n-channel D- MOSFET.

Question 16

An IGBT has the output characteristics of a but is - controlled like a MOSFET.

A)FET, voltage
B)BJT, voltage
C)FET, current
D)BJT, current

Question 17

A FET that has no IDSS parameter is the

A)DE- MOSFET.
B)E- MOSFET.
C)V- MOSFET.
D)JFET.

Question 18

Refer to a)in the figure above. This symbol identifies

A)a p-channel D- MOSFET.
B)an n-channel E- MOSFET.
C)an n-channel D- MOSFET.
D)a p-channel E- MOSFET.

Question 19

Refer to the figure above. In this circuit, VGS is biased correctly for proper operation. This means that VGS is

A)0 V.
B)positive.
C)negative.
D)either negative or positive.

Question 20

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

A)self- bias.
B)voltage- divider bias.
C)gate bias.
D)source bias.

Question 21

The gate- source junction of a JFET is

A)normally reverse- biased.
B)normally not biased.
C)a low resistance path for dc current when reverse- biased.
D)normally forward- biased.

Question 22

The simplest method to bias a D- MOSFET is to

A)set VGS = 0.
B)select the correct value RD.
C)set VGS = - 4.
D)set VGS = +4.

Question 23

Refer to b)in the figure above. This symbol identifies

A)a p-channel D- MOSFET.
B)a p-channel E- MOSFET.
C)an n-channel D- MOSFET.
D)an n-channel E- MOSFET.

Question 24

JFETs are often called

A)one- way switches.
B)unipolar devices.
C)bipolar devices.
D)two- way switches.

Question 25

For a JFET, there is maximum drain current when

A)VDS is zero.
B)VGS is zero.
C)the drain and source are interchanged.
D)VGS equals VGSoff).

Question 26

Refer to d)in the figure above. This symbol identifies

A)a p-channel E- MOSFET.
B)a p-channel D- MOSFET.
C)an n-channel E- MOSFET.
D)an n-channel D- MOSFET.

Question 27

A JFET manufacturer's data sheet specifies VGSoff)= - 8 V and IDSS = 6 mA. When VGS = - 4 V, the value of ID would be

A)4 mA.
B)1.5 mA.
C)1.25 mA.
D)6 mA.

Question 28

Refer to a)in the figure above. If ID = 4 mA, the value of VDS is

A)12 V.
B)0 V.
C)4 V.
D)8 V.

Question 29

The depletion- mode MOSFET can

A)operate with positive as well as negative gate voltages.
B)operate with only positive gate voltages.
C)not operate in the ohmic region.
D)operate with only negative gate voltages.

Question 30

A good application for a V- MOSFET would be as a

A)low power amplifier.
B)substitute for a diode.
C)low input impedance device.
D)power amplifier.

Question 31

An n-channel E- MOSFET conducts when it has

A)VGS > VP.
B)a thin layer of positive charges in the substrate region near the SiO2 layer.
C)a thin layer of negative charges in the substrate region near the SiO2 layer.
D)VDS > 0.

Question 32

For proper operation, an n-channel E- MOSFET should be biased so that VGS is

A)negative.
B)either positive or negative.
C)- 4 V.
D)positive.

Question 33

For an enhancement- mode MOSFET, the minimum VGS required to produce drain current is called the

A)threshold voltage, designated VGSth).
B)breakover voltage.
C)IDss.
D)blocking voltage, designated VB.

Question 34

The channel width in a JFET is controlled by

A)increasing reverse bias on the drain- source junction.
B)varying drain voltage.
C)increasing forward bias on the gate- source junction.
D)varying gate voltage.

Question 35

When operated in the ohmic area, a JFET acts like an)

A)small resistor.
B)current source.
C)voltage source.
D)insulator.

Question 36

Field effect transistors are also known as

A)three- charge carrier devices.
B)unipolar devices.
C)bipolar devices.
D)None of the above.

Question 37

A _ change in VDS will produce a change in ID.

A)small, large
B)small, small
C)large, small
D)large, large