E-MOSFET

Question 1

E-MOSFET

Answer 1

Enhancement Mode - Metal Oxide
Semiconductor Field Effect Transistor

Question 2

A ____________ is used as the foundation on which the device is constructed.

N-Channel E-MOSFET Construction

Answer 2

p-type substrate

Question 3

The ________ and ________ terminals are connected through metallic contacts to n-doped regions.

N-Channel E-MOSFET Construction

Answer 3

Drain (D) and Source (S)

Question 4

The ________________ between two n-doped regions is the primary difference between depletion and enhancement type MOSFET.

N-Channel E-MOSFET Construction

Answer 4

absence of channel

Question 5

The ________ isolate the gate from the region between the source and drain.

N-Channel E-MOSFET Construction

Answer 5

SiO2 layer

Question 6

when VGS=0V and VDS=0, the absence of channel between drain and source will result in __________.

N-Channel E-MOSFET Construction (Basic Operation)

Answer 6

zero current

Question 7

when VGS=0 and VDS is some positive voltage, there exist ____________ biased junction between the n-doped regions and p-substrate and absence of channel between source and drain which cause zero current to flow.

N-Channel E-MOSFET Construction (Basic Operation)

Answer 7

two reversed

Question 8

Thus, when VGS=0 and voltage VDS is applied across drain to source terminals, the absence of channel will result in ________________ as against the ________________ where ID=IDSS when VGS=0.

N-Channel E-MOSFET Construction (Basic Operation)

Answer 8

zero drain current, depletion type MOSFET

Question 9

When VGS and VDS are set to some positive voltages, then the positive potential get established at ________ and the ________ with respect to the ________.

N-Channel E-MOSFET Construction (Basic Operation)

Answer 9

drain, gate, source

Question 10

The positive potential at gate will repel the holes in ____________ along the edge of the SiO2 layer however the electrons which is ____________ in p-substrate will be attracted to the ________________ and get accumulated in the region near the surface of the SiO2 layer.

N-Channel E-MOSFET Construction (Basic Operation)

Answer 10

p-type substrate, minority carrier, positive gate

Question 11

The insulating SiO2 layer prevent the electrons being _________________________.

N-Channel E-MOSFET Construction (Basic Operation)

Answer 11

absorbed by positive gate

Question 12

As VGS increases, the concentration of___________ increases such that a channel is induced between drain and source which allow flow of electrons from drain to source hence the flow of ____________.

N-Channel E-MOSFET Construction (Basic Operation)

Answer 12

electrons, drain current

N-Channel E-MOSFET Construction (Basic Operation)

Question 13

The level of VGS that starts flow of current is called ____________ VGS(th) ot VT. For N-type MOSFET it is referred to _______

Answer 13

threshold voltage, VTN

Question 14

Since the channel is not in existent with VGS=0 and enhance by the application of positive VGS, this type of MOSFET is called an __________________.

N-Channel E-MOSFET Construction (Basic Operation)

Answer 14

enhancement mode MOSFET

Question 15

Both the depletion and enhancement type MOSFETs have ________________.

N-Channel E-MOSFET Construction (Basic Operation)

Answer 15

enhancement region

Question 16

The depletion type MOSFETs can operate in both depletion and enhancement regions whereas enhancement type MOSFET can only operate in ___________________.

N-Channel E-MOSFET Construction (Basic Operation)

Answer 16

enhancement regions

Question 17

With a fixed VDS drain-source voltage connected across the ________, we can plot the values of drain current, ID with varying values of VGS to obtain a graph of the MOSFET’s forward DC characteristics. These characteristics give the ____________________, gm of the transistor.

N-channel E-MOSFET I-V Characteristics

Answer 17

E-MOSFET, transconductance

Question 18

when VGS>VTN, application of a small VDS causes a current ID to flow through an ________________ which increases with increase in _____.

N-Channel E-MOSFET Construction (Basic Operation: Applying a small VDS)

Answer 18

induced channel, VDS

Question 19

An E-MOSFET with a small VDS is applied acts as a ____________ whose value is determined by _____.

N-Channel E-MOSFET Construction (Basic Operation: Applying a small VDS)

Answer 19

resistance, VGS

Question 20

when VGS<VTN, ID=___, R=_______

N-Channel E-MOSFET Construction (Basic Operation: Applying a small VDS)

Answer 20

ID=0, R=infinity

Question 21

When VGS>VTN, a ________ is induced causing flow of electrons, hence flow of ID, making R __________.

N-Channel E-MOSFET Construction (Basic Operation: Applying a small VDS)

Answer 21

channel, finite

Question 22

as VGS increases, free electrons increases, drain current increases and ____ decreases.

N-Channel E-MOSFET Construction (Basic Operation: Applying a small VDS)

Answer 22

R

Question 23

The dashed line between the source and drain in enhancement type MOSFET reflects that ____________ is physically constructed between source to drain. Channel get induced when _________.

Symbol of MOSFET

Answer 23

no channel, VGS>VT

Question 24

This transconductance relates the output current to the input voltage representing the gain of the ____________. The slope of the transconductance curve at any point along it is therefore given as: ____________ for a constant value of VDS.

N-channel E-MOSFET I-V Characteristics

Answer 24

transistor, gm = ID/VGS

Question 25

When VGS>VTN, a ________ is induced and application of positive VDS cause ____________ to flow. ## Footnote N-Channel E-MOSFET Construction (Basic Operation)

Answer 25

channel, drain current

Question 26

Now if you keep VGS fixed and VDS is increased, the drain terminal becomes more positive than ________. The charge carriers get attracted towards drain rather getting accumulated near SiO2 surface and hence the charge density in the channel towards drain decreases. Therefore, increase in "VDS" will ____________ the induced channel towards drain but the "high potential" at drain attract increased number of charge carriers to flow through ______________. ## Footnote N-Channel E-MOSFET Construction (Basic Operation)

Answer 26

gate, narrow down, narrow channel

Question 27

with further increase in VDS, the drain current will eventually reach to a ________________ that occurs due to ________ process depicted by the narrower channel. ## Footnote N-Channel E-MOSFET Construction (Basic Operation)

Answer 27

saturation level, pinch-off

Question 28

Increase in VGS will cause the pinch-off to occur at higher value of ____ than the earlier. ## Footnote N-Channel E-MOSFET Construction (Basic Operation)

Answer 28

VDS

Question 29

Thus higher the VGS, higher is the current flow and higher is the value of VDS that cause ________________ condition. ## Footnote N-Channel E-MOSFET Construction (Basic Operation)

Answer 29

pinch-off or saturation

Question 30

The saturation value of VDS is given by _____________ ## Footnote N-Channel E-MOSFET Construction (Basic Operation)

Answer 30

VDsat = VGS - VT

Question 31

If VGS < VT, the drain current ID = ____ and the MOSFET is said to be in __________ ## Footnote N-Channel E-MOSFET Construction (Basic Operation)

Answer 31

ID=0, cutoff region

Question 32

for VGS > VT and VDS <= VGS-VT, the MOSFET operate in _______________ or _______________ ## Footnote N-Channel E-MOSFET Construction (Basic Operation)

Answer 32

non-saturation or triode region

Question 33

for VGS >VT and VDS >= VGS-VT, the MOSFET operate in __________ or _______________ ## Footnote N-Channel E-MOSFET Construction (Basic Operation)

Answer 33

saturation, pinch-off region

Question 34

when VGS > VTN and for a small values of VDS, a complete ________ from ________ to ________ is __________ ## Footnote N-Channel E-MOSFET Construction (Drain Characteristics Curve)

Answer 34

channel, drain to source, induced

Question 35

____________ acts as a resistor whose value is determined by VGS ## Footnote N-Channel E-MOSFET Construction (Drain Characteristics Curve)

Answer 35

E-MOSFET

Question 36

when VGS > VTN and VDS is larger value but VDS < _________ ## Footnote N-Channel E-MOSFET Construction (Drain Characteristics Curve)

Answer 36

VDS(sat)

Question 37

the _______________charge density near the drain _____________ and hence the incremental conductance of the channel at the drain ____________, ## Footnote N-Channel E-MOSFET Construction (Drain Characteristics Curve)

Answer 37

induced inversion, decreases, decreases

Question 38

when VGS > VTN and VDS = VDS(sat) , the ____________charge density at the drain terminal is _______ hence the incremental channel conductance at the drain is zero ## Footnote N-Channel E-MOSFET Construction (Drain Characteristics), po

Answer 38

induced inversion, zero

Question 39

_____________ is at drain ## Footnote N-Channel E-MOSFET Construction (Drain Characteristics)

Answer 39

Pinch-off point

Question 40

when VGS >VTN and VDS > VDS(sat), the ________ in the channel at which the inversion charge is zero moves toward the ____________ ## Footnote N-Channel E-MOSFET Construction (Drain Characteristics)

Answer 40

point, source terminal

Question 41

The ________________________ is similar to the n-channel except that the voltage polarities and current directions are reversed. ## Footnote p-channel Enhancement-type MOSFET

Answer 41

p-channel Enhancement-type MOSFET

Question 42

The ___________ operate in pinch-off/saturation region ## Footnote N-Channel E-MOSFET Construction (Drain Characteristics)

Answer 42

MOSFET

Question 43

An essential step in the design of a MOSFET amplifier circuit is the establishment of an appropriate __________________. ## Footnote Biasing Circuits used for MOSFET

Answer 43

dc operating point

Question 44

Biasing circuit ensures operation of MOSFET in the ______________ for all expected input-signal levels. ## Footnote Biasing Circuits used for MOSFET

Answer 44

saturation region

Question 45

The operating point of the MOSFET is located at the coordinate (VDS, ID) on the ___________________. ## Footnote Biasing Circuits used for MOSFET

Answer 45

characteristic graph

Question 46

A popular biasing arrangement for enhancement-type MOSFETS

Answer 46

Feedback Biasing

Question 47

Here the large feedback resistance ___ forces the _________ at the gate to be equal to that at the drain (because IG = 0 ). Since IG = 0mA and VRG=0 V, the dc equivalent network appears as shown ## Footnote Feedback Biasing

Answer 47

RG, dc voltage

Question 48

A direct connection now exists between _______ and ______ ## Footnote Feedback Biasing

Answer 48

drain and gate

Question 49

Another popular biasing arrangement for enhancement-type MOSFETS

Answer 49

Voltage Divider Biasing

Question 50

It is the ratio of change in the drain source voltage (Δ VDS ) to the change in drain current (ΔlD) at constant gate-source voltage. ## Footnote Parameters of E-MOSFET

Answer 50

AC drain resistance (rd)

Question 51

It is the ratio of change in drain current (ΔlD) to the change in gate source voltage (ΔVGS). ## Footnote Parameters of E-MOSFET

Answer 51

Transconductance parameter (gm)

Question 52

It is the ratio of change in drain-source voltage (ΔVDS) to the change in gate-source voltage (ΔVGS) . ## Footnote Parameters of E-MOSFET

Answer 52

Amplification Factor (µ)

Question 53

The __________ behaves as a voltage- controlled current source. ## Footnote AC equivalent circuit of n channel E-MOSFET

Answer 53

MOSFET

Question 54

It provides a drain current proportional to vgs. ## Footnote AC equivalent circuit of n channel E-MOSFET

Answer 54

E MOSFET

Question 55

The input resistance is very high ideally infinite. ## Footnote AC equivalent circuit of n channel E-MOSFET

Answer 55

E-MOSFET

Question 56

The output resistance is also high ## Footnote AC equivalent circuit of n channel E-MOSFET

Answer 56

E-MOSFET

Question 57

Since rd is __________, it can be neglected from the ckt ## Footnote AC equivalent circuit of n channel E-MOSFET

Answer 57

very high

Question 58

In the ______________, the MOSFET acts as a voltage-controlled current source: Changes in the ___________ voltage VGS causes changes in the _______ current ID. ## Footnote E-MOSFET as an Amplifier

Answer 58

saturation region, gate-to-source, drain

Question 59

Thus the saturated MOSFET behaves as ________________ amplifier ## Footnote E-MOSFET as an Amplifier

Answer 59

trans-conductance

Question 60

changes in vi causes changes in ID which in turn changes ____. ## Footnote E-MOSFET as an Amplifier

Answer 60

Vo

Question 61

Thus, the trans-conductance amplifier is converted into a __________ amplifier. ## Footnote E-MOSFET as an Amplifier

Answer 61

voltage

Question 62

Load line equation: ## Footnote Large signal Transfer Characteristic of MOSFET Circuit

Answer 62

Vo = VDS = VDD - (RD)(ID)

Question 63

for vi < VTH the ____________ will be cut off, ID will be ______, and VO = VDS = VDD (point A). ## Footnote Large signal Transfer Characteristic of MOSFET Circuit

Answer 63

transistor, zero

Question 64

As Vi exceeds VTH the transistor turns ____, ID ________, and VO __________. This corresponds to points along the segment of the load line from A to В. ## Footnote Large signal Transfer Characteristic of MOSFET Circuit

Answer 64

on, increases, decreases

Question 65

_________________ operation continues until VO decreases below VDSsat ## Footnote Large signal Transfer Characteristic of MOSFET Circuit

Answer 65

Saturation-region

Question 66

When VDS < VDSsat the MOSFET enters its ______________ ## Footnote Large signal Transfer Characteristic of MOSFET Circuit

Answer 66

triode region

Question 67

For Vi > VIB, the transistor is driven deeper into the triode region and voltage decreases slowly towards ______. ## Footnote Large signal Transfer Characteristic of MOSFET Circuit

Answer 67

zero

Question 68

When the MOSFET is used as a _________, it is operated at the extreme points of the _____________. ## Footnote MOSFET as a Switch

Answer 68

switch, transfer curve

Question 69

The device is ____________ by keeping, V < VTH which provide VO = VDD ## Footnote MOSFET as a Switch

Answer 69

turned off

Question 70

The switch is turned on by applying a voltage close to _____. Here, vo is ____________. ## Footnote MOSFET as a Switch

Answer 70

VDD, very small

Question 71

For the FET to operate as a ______________, the transistor must be biased in the ___________ region, and the instantaneous drain current ID and drain-to-source voltage VDS must be confined to the ___________ region. ## Footnote E-MOSFET Common Source Amplifier

Answer 71

linear amplifier, saturation, saturation

Question 72

The device is biased at a somewhere near to the middle of the curve. The voltage signal to be amplified vi is then ________________ on the dc bias voltage. ## Footnote E-MOSFET Common Source Amplifier

Answer 72

superimposed