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FET Amplifiers

Terms in this set (39)

A common-gate amplifier is similar in configuration to which BJT amplifier?
A.common-emitter
B.common-collector
C.common-base
D.emitter-follower
C
The theoretical efficiency of a class D amplifier is
A.75%.
B.85%.
C.90%.
D.100%.
D
A common-source amplifier is similar in configuration to which BJT amplifier?
A.common-base
B.common-collector
C.common-emitter
D.emitter-follower
C
A BJT is a ________-controlled device.
A.current
B.voltage
A
A common-drain amplifier is similar in configuration to which BJT amplifier?
A.common-emitter
B.common-collector
C.common-base
D.common-gate
B
For what value of ID is gm equal to 0.5 gm0?
A.0 mA
B.0.25 IDSS
C.0.5 IDSS
D.IDSS
B
Where do you get the level of gm and rd for an FET transistor?
A.from the dc biasing arrangement
B.from the specification sheet
C.from the characteristics
D.All of the above
D
The class D amplifier uses what type of transistors?
A.JFETs
B.BJTs
C.MOSFETs
D.any of the above
C
What is (are) the function(s) of the coupling capacitors C1 and C2 in an FET circuit?
A.to create an open circuit for dc analysis
B.to isolate the dc biasing arrangement from the applied signal and load
C.to create a short-circuit equivalent for ac analysis
D.All of the above
D
An FET is a ________-controlled device.
A.current
B.voltage
B
What is the input resistance (Rin(source)) of a common-gate amplifier?
A.Rs
B. (1/gm) || Rs
C.1 / gm
D.none of the above
C
There is a ________º phase inversion between gate and source in a source follower.
A.0
B.90
C.180
D.none of the above
A
Which of the following is a required condition to simplify the equations for Zo and Av for the self-bias configuration?
A.rd 10RD
B.rd = RD
C.rd 10RD
D.None of the above
C
The steeper the slope of the ID versus VGS curve, the ________ the level of gm.
A.less
B.same
C.greater
C
What is the typical value for the input impedance Zi for JFETs?
A.100 k ohms
B.1 M ohms
C.10 M ohms
D.1000 M ohms
D
MOSFETs make better power switches than BJTs because they have
A.lower turn-off times.
B.lower on-state resistance.
C.a positive temperature coefficient.
D.all of the above
D
When VGS = 0.5 Vp gm is ________ the maximum value.
A.one-fourth
B.one-half
C.three-fourths
B
MOSFET digital switching is used to produce which digital gates?
A.inverters
B.NOR gates
C.NAND gates
D.all of the above
D
Which type of FETs can operate with a gate-to-source Q-point value of 0 V?
A.JFET
B.E-MOSFET
C.D-MOSFET
C
On which of the following parameters does rd have no or little impact in a source-follower configuration?
A.Zi
B.Zo
C.Av
D.All of the above
D
Class D amplifiers differ from all other classes of amplifiers because
A.the output transistors are operated as switches.
B.of their very low input capacitance.
C.of their high-frequency response capabilities.
D.they employ dual MOSFETs.
A
Which FET amplifier(s) has (have) a phase inversion between input and output signals?
A.common-gate
B.common-drain
C.common-source
D.all of the above
C
What common factor determines the voltage gain and input resistance of a common-gate amplifier?
A.RD
B.RL
C.gm
C
For the fixed-bias configuration, if ________.
A.RD
B. RD || rd
C.RG
D. - gm * (RD || rd)
B
The more horizontal the characteristic curves on the drain characteristics, the ________ the output impedance.
A.less
B.same
C.greater
C
Which of the following is (are) related to depletion-type MOSFETs?
A. can be negative, zero, or positive.
B.gm can be greater or smaller than gm0.
C.ID can be larger than IDSS.
D.All of the above
D
The input resistance at the gate of a FET is extremely
A.high.
B.low.
A
FET amplifiers provide ________.
A.excellent voltage gain
B.high input impedance
C.low power consumption
D.All of the above
D
CMOS digital switches use
A.n-channel and p-channel D-MOSFETs in series.
B.n-channel and p-channel D-MOSFETs in parallel.
C.n-channel and p-channel E-MOSFETs in series.
D.n-channel and p-channel E-MOSFETs in parallel.
C
What is the range of gm for JFETs?
A.1 S to 10 S
B.100 S to 1000 S
C.1000 S to 5000 S
D.10000 S to 100000 S
C
Calculate gm and rd if yfs = 4 mS and yos = 15S.
A.4 mS, 66.7 k
B.4 mS, 15 k
C.66.7 k, 4 mS
D.None of the above
A
What limits the signal amplitude in an analog MOSFET switch?
A.the switch input capacitance
B.VGS(th)
C.the switch's power handling
D.VDS
B
Input resistance of a common-drain amplifier is
A.RG || RIN(gate).
B.RG + RIN(gate).
C.RG.
D.RIN(gate).
A
A JFET cascade amplifier employs
A.2 common-gate amplifiers.
B.2 common-source amplifiers.
C.1 common-gate and 1 common-source amplifier.
D.1 common-gate and 1 common-drain amplifier.
C
E-MOSFETs are generally used in switching applications because
A.of their very low input capacitance.
B.of their threshold characteristic (VGS(th)).
C.of their high-frequency response capabilities.
D.of their power handling.
B
For an FET small-signal amplifier, one could go about troubleshooting a circuit by ________.
A.viewing the circuit board for poor solder joints
B.using a dc meter
C.applying a test ac signal
D.All of the above
D
The E-MOSFET is quite popular in ________ applications.
A.digital circuitry
B.high-frequency
C.buffering
D.All of the above
D
In a common-source amplifier, the purpose of the bypass capacitor, C2, is to
A.keep the source effectively at ac ground.
B.provide a dc path to ground.
C.provide coupling to the input.
D.provide coupling to the load.
A
If ID = IDSS / 2, gm = ________ gmo.
A.1
B.0.707
C.0.5
B
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