Electronic Devices 3- FET Flashcards
For a JFET, the value of VDS at which ID becomes essentially constant is the
pinch-off voltage.
The ________ has a physical channel between the drain and source.
D-MOSFET
What type(s) of gate-to-source voltage(s) can a depletion MOSFET (D-MOSFET) operate with?
zero
positive
negative
any of the above
Midpoint bias for a D-MOSFET is ID = ________, obtained by setting VGS = 0.
IDSS
On the drain characteristic curve of a JFET for VGS = 0, the pinch-off voltage is
between the ohmic area and the constant current area.
Which of the following devices has the highest input resistance?
MOSFET
The value of VGS that makes ID approximately zero is the
cutoff voltage.
The JFET is always operated with the gate-source pn junction ________ -biased.
reverse
A dual-gated MOSFET is
either a depletion or an enhancement MOSFET.
What three areas are the drain characteristics of a JFET (VGS = 0) divided into?
ohmic, constant-current, breakdown
In a self-biased JFET circuit, if VD = VDD then ID = ________.
0
The resistance of a JFET biased in the ohmic region is controlled by
VGS
High input resistance for a JFET is due to
the gate-source junction being reverse-biased.
For a JFET, the change in drain current for a given change in gate-to-source voltage, with the drain-to-source voltage constant, is
forward transconductance.
If VD is less than expected (normal) for a self-biased JFET circuit, then it could be caused by a(n)
open RG.
open gate lead.
FET internally open at gate.
all of the above
Which of the following ratings appear(s) in the specification sheet for an FET?
Voltages between specific terminals
Current levels
Power dissipation
All of the above
What is the level of drain current ID for gate-to-source voltages VGS less than (more negative than) the pinch-off level?
zero amperes
What is the level of IG in an FET?
Zero amperes
What is the range of an FET’s input impedance?
1 M to several hundred M
Which of the following applies to a safe MOSFET handling?
Always pick up the transistor by the casing.
Power should always be off when network changes are made.
Always touch ground before handling the device.
All of the above
At which of the following condition(s) is the depletion region uniform?
No bias
Which of the following controls the level of ID?
VGS
It is the insulating layer of ________ in the MOSFET construction that accounts for the very desirable high input impedance of the device.
SiO2
The BJT is a ________ device. The FET is a ________ device.
bipolar, unipolar
The drain current will always be one-fourth of IDSS as long as the gate-to-source voltage is ________ the pinch-off value.
one-half
The transfer curve is not defined by Shockley’s equation for the ________.
enhancement-type MOSFET
The region to the left of the pinch-off locus is referred to as the ________ region.
ohmic
Which of the following transistor(s) has (have) depletion and enhancement types?
MOSFET
The three terminals of the JFET are the ________, ________, and ________.
gate, drain, source
Which of the following is (are) the terminal(s) of a field-effect transistor (FET).
Drain
Gate
Source
All of the above
A BJT is a ________-controlled device. The JFET is a ________ - controlled device.
current, voltage
How many terminals can a MOSFET have?
3 or 4
The level of VGS that results in ID = 0 mA is defined by VGS = ________.
VP
Which of the following FETs has the lowest input impedance?
JFET
Which of the following applies to MOSFETs?
No direct electrical connection between the gate terminal and the channel
Desirable high input impedance
Uses metal for the gate, drain, and source connections
All of the above
At which of the following is the level of VDS equal to the pinch-off voltage?
When ID becomes equal to IDSS
When VGS is zero volts
IG is zero
All of the above
Which of the following represent(s) the cutoff region for an FET?
ID = 0 mA
VGS = VP
IG = 0
All of the above
Which of the following is (are) the advantage(s) of VMOS over MOSFETs?
Reduced channel resistance
Higher current and power ratings
Faster switching time
All of the above
Hand-held instruments are available to measure ________ for the BJT.
betaDC
Which of the following input impedances is not valid for a JFET?
10^8
Which of the following is (are) not an FET?
p-n channel
For the FET, the relationship between the input and output quantities is ________ due to the ________ term in Shockley’s equation.
nonlinear, squared
Which of the following is (are) true of a self-bias configuration compared to a fixed-bias configuration?
One of the dc supplies is eliminated.
A resistor RS is added.
VGS is a function of the output current ID.
All of the above
The input controlling variable for a(n) ________ is a current level and a voltage level for a(n) ________.
BJT, FET
Through proper design, a ________ can be introduced that will affect the biasing level of a voltage-controlled JFET resistor.
thermistor
On the universal JFET bias curve, the vertical scale labeled ________ can, in itself, be used to find the solution to ________ configurations.
m, fixed-bias
Which of the following current equations is true?
ID = IS
Which of the following represents the voltage level of VGS in a self-bias configuration?
VS
Which of the following is a false statement regarding the dc load line when comparing self-bias and voltage-divider configurations?
Both cross the origin.
For the noninverting amplifier, one of the most important advantages associated with using a JFET for control is the fact that it is ________ rather than ________ control.
ac, dc
What is the approximate current level in the gate of an FET in dc analysis?
0A
Which of the following describe(s) the difference(s) between JFETs and depletion-type MOSFETs?
VGS can be positive or negative for the depletion-type.
ID can exceed IDSS for the depletion-type.
The depletion-type can operate in the enhancement mode.
All of the above
A common-gate amplifier is similar in configuration to which BJT amplifier?
common-base
The theoretical efficiency of a class D amplifier is
100%.
A common-source amplifier is similar in configuration to which BJT amplifier?
common-emitter
A common-drain amplifier is similar in configuration to which BJT amplifier?
common-collector
Where do you get the level of gm and rd for an FET transistor?
from the dc biasing arrangement
from the specification sheet
from the characteristics
All of the above
The class D amplifier uses what type of transistors?
MOSFETs
What is (are) the function(s) of the coupling capacitors C1 and C2 in an FET circuit?
to create an open circuit for dc analysis
to isolate the dc biasing arrangement from the applied signal and load
to create a short-circuit equivalent for ac analysis
All of the above
What is the input resistance (Rin(source)) of a common-gate amplifier?
1 / gm
There is a ________º phase inversion between gate and source in a source follower.
0
Which of the following is a required condition to simplify the equations for Zo and Av for the self-bias configuration?
rd >_10RD
The steeper the slope of the ID versus VGS curve, the ________ the level of gm.
greater
What is the typical value for the input impedance Zi for JFETs?
1000 Mohms
MOSFETs make better power switches than BJTs because they have
lower turn-off times.
lower on-state resistance.
a positive temperature coefficient.
all of the above
When VGS = 0.5 Vp gm is ________ the maximum value.
one-half
MOSFET digital switching is used to produce which digital gates?
inverters
NOR gates
NAND gates
all of the above
Which type of FETs can operate with a gate-to-source Q-point value of 0 V?
D-MOSFET
On which of the following parameters does rd have no or little impact in a source-follower configuration?
Zi
Zo
Av
All of the above
Class D amplifiers differ from all other classes of amplifiers because
the output transistors are operated as switches.
Which FET amplifier(s) has (have) a phase inversion between input and output signals?
common-source
What common factor determines the voltage gain and input resistance of a common-gate amplifier?
gm
The more horizontal the characteristic curves on the drain characteristics, the ________ the output impedance.
greater
Which of the following is (are) related to depletion-type MOSFETs?
Vgs(q)can be negative, zero, or positive.
gm can be greater or smaller than gm0.
ID can be larger than IDSS.
All of the above
The input resistance at the gate of a FET is extremely
high
FET amplifiers provide ________.
excellent voltage gain
high input impedance
low power consumption
All of the above
CMOS digital switches use
n-channel and p-channel E-MOSFETs in series.
What is the range of gm for JFETs?
1000uS to 5000uS
What limits the signal amplitude in an analog MOSFET switch?
VGS(th)
Input resistance of a common-drain amplifier is
RG || RIN(gate).
A JFET cascade amplifier employs
1 common-gate and 1 common-source amplifier.
E-MOSFETs are generally used in switching applications because
of their threshold characteristic (VGS(th)).
For an FET small-signal amplifier, one could go about troubleshooting a circuit by ________.
viewing the circuit board for poor solder joints
using a dc meter
applying a test ac signal
All of the above
The E-MOSFET is quite popular in ________ applications.
digital circuitry
high-frequency
buffering
All of the above
In a common-source amplifier, the purpose of the bypass capacitor, C2, is to
keep the source effectively at ac ground.
If ID = IDSS / 2, gm = ________ gmo.
0.707
