Explore topic-wise InterviewSolutions in .

This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.

51.

In a p-channel E-MOSFET, the current becomes constant in saturation region. Which of the following condition depicts this?(a) VDS = 2Vgs-Vt(b) VDS > Vgs-Vt(c) VDS ≤ Vgs-Vt(d) VDS = VgsThe question was asked in semester exam.I want to ask this question from The Insulated-Gate FET(MOSFET) topic in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer» CORRECT option is (c) VDS ≤ Vgs-Vt

Explanation: The p-channel E-MOSFET operates in the saturation region when VDS > Vgs-Vt, since we will be FIXING the gate to source VOLTAGE and threshold is a SYSTEM constant, WHATEVER may be the value of VDS which is lesser than Vgs-Vt, the current remains the same.
Discussion
52.

For a FET when will maximum current flows?(a) Vgs = 0V(b) Vgs = 0v and Vds >= |Vp|(c) VDS >= |Vp|(d) Vp = 0The question was posed to me at a job interview.The origin of the question is The Junction Field-Effect Transistor topic in division Field-Effect Transistors of Electronic Devices & Circuits

Answer» RIGHT ANSWER is (B) Vgs = 0v and Vds >= |Vp|

Easy explanation: For a FET the current reaches maximum that is IDSS OCCURS when Vgs = 0V and VDS >= |Vp|
Discussion
53.

Which of the following is true about the common Source amplifier?(a) It has low input impedance(b) It has high output impedance(c) Infinite gain(d) Phase reversal voltage outputThe question was posed to me by my school teacher while I was bunking the class.This question is from The Common Source Amplifier topic in section Field-Effect Transistors of Electronic Devices & Circuits

Answer»

The correct answer is (d) Phase REVERSAL VOLTAGE output

The explanation is: If we CONSIDER a FIXED bias based amplifier, the voltage GAIN is Av=-gm RD,

The negative sign indicates that the voltage waveform is phase reversed by 180 degrees.
Discussion
54.

Determine the value of output impedance for JFET, if the value of gm =1mS?(a) 1Kohm(b) 0(c) 100Kohm(d) 5KohmThe question was asked by my college professor while I was bunking the class.I'd like to ask this question from The FET Small-Signal Model topic in division Field-Effect Transistors of Electronic Devices & Circuits

Answer»

The correct OPTION is (a) 1Kohm

Easiest explanation: OUTPUT impedance=inverse of trans CONDUCTANCE

 Output impedance=1/1mS

 Output impedance=1Kohm.
Discussion
55.

Where does the transfer curve lie for a p- channel FET?(a) First quadrant(b) Second quadrant(c) Third quadrant(d) Fourth quadrantThe question was posed to me in an online quiz.This interesting question is from The JFET Volt-Ampere Characteristics topic in chapter Field-Effect Transistors of Electronic Devices & Circuits

Answer» RIGHT choice is (a) First quadrant

The best explanation: For a P- channel FET, since the pinch off lies on right side of the origin, the CURRENT Id will increase from VP and rise to its left until it REACHES IDSS. Usually IDSS lies on positive Y axis, therefore we can say transfer CURVE for the p-channel FET lies on first quadrant.
Discussion
56.

For low value of VDS, the JFET behaves like a __________(a) Voltage Variable Resistor(b) Constant Voltage Device(c) Amplifier(d) SwitchI had been asked this question in an interview.Enquiry is from The JFET Volt-Ampere Characteristics topic in division Field-Effect Transistors of Electronic Devices & Circuits

Answer» CORRECT choice is (a) Voltage VARIABLE Resistor

To elaborate: When VDS voltage is very less, there will not be much current flow, SINCE as the VDS changes, the current value changes very LITTLE. HENCE we can say that FET works as a voltage controlled Resistor.
Discussion
57.

The depletion type MOSFET is equivalent to normally closed switch.(a) True(b) FalseI got this question in an international level competition.This intriguing question originated from The Insulated-Gate FET(MOSFET) in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer» RIGHT ANSWER is (a) True

The best I can explain: The DEPLETION type has its gate short circuited with SOURCE terminal and hence always in On condition .Therefore we can SAY it as closed switch.
Discussion
58.

What is the maximum value of gain of an amplifier?(a) 140dB(b) 130dB(c) 120db(d) 100dBI got this question during an interview for a job.My enquiry is from The Junction Field-Effect Transistor topic in section Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Right choice is (c) 120db

The explanation: The maximum GAIN of AMPLIFIER is 1000000. When we CONSIDER this in decibel scale, it gives 120dB => gain in dB = 20log10(100000) = 120dB.
Discussion
59.

Two identical FETs, each characterized by the parameters g_m and r_d are connected in parallel .The composite FET is then characterized by the parameters_____________(a) gm/2 and 2rd(b) gm/2 and 2rd(c) 2gm and rd/2(d) 2gm and rd/2The question was posed to me during an interview.My question is taken from The Junction Field-Effect Transistor in division Field-Effect Transistors of Electronic Devices & Circuits

Answer»

The correct choice is (C) 2GM and rd/2

Best explanation: By CONVERTING FET into ac EQUIVALENT circuits and CONNECTING them in parallel,

gn = 2gmandrn = rd/2.
Discussion
60.

The pinch off voltage of JFET is 5v. What is its cut off voltage?(a) 2.5V(b) 3V(c) 4V(d) 5VThe question was asked in an online quiz.My doubt is from The Junction Field-Effect Transistor topic in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer» RIGHT answer is (d) 5V

The explanation is: Pinch off voltage =5V

At cut off the gate to source voltage of JFET is equal to pinch off voltage

VGS = VP => Vgs(off) = 5V.
Discussion
61.

MOSFET can be used as ________(a) Voltage controlled capacitor(b) Current controlled capacitor(c) Voltage controlled inductor(d) Current controlled inductorThis question was addressed to me at a job interview.The origin of the question is The Insulated-Gate FET(MOSFET) topic in section Field-Effect Transistors of Electronic Devices & Circuits

Answer» CORRECT ANSWER is (a) Voltage controlled CAPACITOR

The BEST explanation: By using proper TECHNIQUES, MOSFET can be used as Voltage controlled capacitor.
Discussion
62.

If a JFET with length L=10µm, a=2µm, W=8µm, Vp=-4V.What is the value of rds at Vgs = 0V?(a) 2KΩ(b) 5.2KΩ(c) 10KΩ(d) 9.8KΩThis question was posed to me by my college director while I was bunking the class.My question is from The JFET Volt-Ampere Characteristics in chapter Field-Effect Transistors of Electronic Devices & Circuits

Answer» CORRECT option is (d) 9.8KΩ

The EXPLANATION: rds=L/(2aqND µnW) = Nd = 2V/qa^2=1.33×10^21 atoms/m^3

µn=0.15m^2/v-sec

On SUBSTITUTING the VALUES, we get rds=9.8KΩ.
Discussion
63.

The action of JFET in its equivalent circuit can be represented as which of the following?(a) Current controlled current source(b) Current controlled voltage source(c) Voltage controlled current source(d) Voltage controlled Voltage sourceI got this question in homework.I'd like to ask this question from The Junction Field-Effect Transistor topic in section Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Correct option is (c) Voltage CONTROLLED current source

For explanation: In JFET equivalent circuit, the OUTPUT current is controlled by the GATE to source voltage and hence we can SAY it is a Voltage controlled current source.
Discussion
64.

Which of the following statement is true about FET?(a) It has high output impedance(b) It has high input impedance(c) It has low input impedance(d) It does not offer any resistanceThis question was posed to me in examination.My question is based upon The Junction Field-Effect Transistor topic in division Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Right choice is (b) It has high INPUT impedance

To explain: Because of the Sio2 INSULATOR, doped between drain and source at the top, the resistance OFFERED by this is very high. The insulator will STOP the flow of electron from one part to another which ACTS as an open circuit.
Discussion
65.

Which type of material is the channel of a unijunction transistor made up of?(a) PN type(b) It doesn’t affect the working(c) P type(d) N typeThe question was posed to me during an interview.I want to ask this question from The Unijunction Transistors in chapter Field-Effect Transistors of Electronic Devices & Circuits

Answer»

The CORRECT option is (d) N type

To elaborate: The core conducting component is the N-type channel of the transistor. Unijunction transistor CONSISTS of a SINGLE solid piece of N-type SEMICONDUCTOR material forming the main CURRENT carrying channel.
Discussion
66.

A FETcircuit has a transconductance of 2500 µ seconds and drain resistance equals to 10Kohms than voltage gain will be __________(a) 20(b) 25(c) 30(d) 35This question was posed to me during an interview.My question is from A Generalized FET Amplifier in division Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Correct OPTION is (b) 25

To explain I WOULD say: The TRANSCONDUCTANCE, gm is defined as

gm = ΔID / ΔVGS

so gm = Voltage gain / RD

Therefore, voltage gain = gm * RD

=2500*10^-6 * 10 * 10^3

= 25.
Discussion
67.

What is the generalized value for the voltage across resistor RB1 in a unijunction transistor?(a) VRB1 = (RB2 / RB1 + RB2) × VBB(b) VRB1 = (RB2 / RB1 – RB2) × VBB(c) VRB1 = (RB1 / RB1 + RB2) × VBB(d) VRB1 = (RB1 / RB1 – RB2) × VBBThe question was posed to me during an interview for a job.This interesting question is from The Unijunction Transistors topic in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Right choice is (c) VRB1 = (RB1 / RB1 + RB2) × VBB

The explanation is: The generalized value for the voltage across resistor RB1 is (RB1 / RB1 + RB2) × VBB. Where, RB1 and RB2 are the RESISTANCE across two terminals B1 and B2. The voltage VBB is the voltage across the two terminals.
Discussion
68.

Input resistance of common gate of the amplifier is __________(a) zero(b) infinity(c) extremely low(d) extremely highI have been asked this question during an internship interview.The question is from A Generalized FET Amplifier in division Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Correct choice is (c) extremely LOW

To explain I would say: For a Common gate amplifier, Current gain is about unity, input resistance is low, OUTPUT resistance is high a CG stage is a current “buffer”.It takes a current at the input that may have a relatively SMALL Norton equivalent resistance and REPLICATES it at the output port, which is a good current SOURCE due to the high output resistance.
Discussion
69.

Find the gate voltage for voltage divider having R1=R2=1KΩ and VDD=5V?(a) 1V(b) 5V(c) 3V(d) 2.5VI got this question in an internship interview.My question is based upon Biasing the FET topic in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer» CORRECT ANSWER is (d) 2.5V

Easy EXPLANATION: VG = R2×VDD/R1+R2

=>VG=1×5/2

=> VG= 2.5V.
Discussion
70.

A Self bias configuration contains RD=3.3,Rs=1 KΩ,RG=1MΩ and gm=1.5mS. Determine Av?(a) -2(b) 3(c) -4(d) 5This question was posed to me by my school principal while I was bunking the class.My question is taken from The Common Source Amplifier topic in section Field-Effect Transistors of Electronic Devices & Circuits

Answer» CORRECT choice is (a) -2

The EXPLANATION: Av=-gm RD/ (1+gm RS) because RS is GIVEN and it is not bypassed.

Av=-1.5×3.3KΩ/ (1+1.5×1)

Av=-2.
Discussion
71.

What is the value of resultant gm if two non identical FETs are connected in parallel?(a) (µ1 rd1 + µ2 rd2)/ (rd1+rd2)(b) (µ1 rd2 + µ2 rd1)/ (rd1+rd2)(c) 0(d) µ1 rd1+ µ2 rd2I got this question during an interview.The doubt is from The JFET Volt-Ampere Characteristics in division Field-Effect Transistors of Electronic Devices & Circuits

Answer»

The correct answer is (b) (µ1 rd2 + µ2 rd1)/ (rd1+rd2)

The best explanation: we know that µ=GM RD

But gm’=gm1+gm2

And rd’=rd1 ×rd2/rd1+ rd2

From the above TWO equations, gm’=(µ1 rd2 + µ2 rd1)/ (rd1+rd2).
Discussion
72.

For a n-channel FET, what is the condition of Vgs for which the current becomes zero?(a) 0(b) 100V(c) Vp(d) InfiniteThe question was posed to me in an international level competition.I would like to ask this question from The Pinch off Voltage Vp topic in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Right answer is (C) Vp

To EXPLAIN: ID=IDSS (1-Vgs/Vp)^2

When ID=0, (1-Vgs/Vp)^2=0

1=Vgs/Vp=> Vgs=Vp.
Discussion
73.

For a p-channel FET, What is the direction of current flow?(a) Source to drain(b) Drain to source(c) Gate to source(d) Gate to drainThis question was addressed to me during a job interview.This intriguing question comes from The Junction Field-Effect Transistor in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer» RIGHT choice is (a) Source to DRAIN

Explanation: When the voltage is lesser than pinch off, the current FLOWS from Source to Drain.

The forward BIAS drain and GATE is the reason for the flow of electron from Drain to source, as the conventional current flows opposite to the electron flow, the current will flow from Source to Drain.
Discussion
74.

If a certain drain JFET has a transconductance of 4ms. And has external drain resistance of 1.5 ohm than ideal voltage gain will be _________(a) 4(b) 5(c) 6(d) 8This question was addressed to me in a national level competition.Query is from A Generalized FET Amplifier topic in chapter Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Right answer is (c) 6

To explain I WOULD SAY: The transconductance, gm is DEFINED as

gm = ΔID / ΔVGS

so gm = Voltage gain / RD

THEREFORE, voltage gain = gm * RD

=4 * 1.5

=6.
Discussion
75.

What are the working regions of a unijunction transistor?(a) Linear region(b) Negative Resistance region(c) Saturation region(d) Cut-off regionI have been asked this question in an international level competition.I need to ask this question from The Unijunction Transistors topic in division Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Correct option is (b) Negative Resistance region

To explain: As soon as the TRANSISTOR reaches the triggering voltage the unijunction transistor will turn on. If the APPLIED voltage INCREASES to the emitter lead, the peak voltage is ACHIEVED. The voltage drops from peak voltage to Valley Point. This happens in spite of the CURRENT increasing; this is because of the negative resistance.
Discussion
76.

Which of the following relation is true about gate current?(a) IG=ID+IS(b) ID=IG(c) IS= IG(d) IG=0The question was posed to me by my school teacher while I was bunking the class.The question is from Biasing the FET topic in chapter Field-Effect Transistors of Electronic Devices & Circuits

Answer»

The CORRECT OPTION is (d) IG=0

To elaborate: The FET physical structure which contains silicon dioxide provides infinite resistance. HENCE no current will FLOW through the GATE terminal.
Discussion
77.

If gm=0.5mS, RS=2KΩ, determine ZOfor source follower?(a) 2KΩ(b) 1KΩ(c) 3KΩ(d) 1.5KΩThis question was addressed to me during an interview.Question is from The Common Drain Amplifier in section Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Correct ANSWER is (B) 1KΩ

To EXPLAIN I WOULD say: ZO=RS||1/gm

=>1/gm=1/0.5mS=>2KΩ

2KΩ||2KΩ=1KΩ,

=>ZO=1KΩ.
Discussion
78.

Output Impedance of Common Drain Amplifier is______________(a) RS+rd(b) RS(c) RS || rd(d) RS||1/gmThis question was posed to me in exam.I'm obligated to ask this question of The Common Drain Amplifier in chapter Field-Effect Transistors of Electronic Devices & Circuits

Answer»
Discussion
79.

Which of the following is the necessary to hold drain current in 0 for p channel E-MOSFET?(a) Vgs > Vt(b) Vgs < Vt(c) Vgs < 2Vt(d) 2Vgs > VtI got this question in a national level competition.Origin of the question is The Insulated-Gate FET(MOSFET) in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Correct answer is (a) Vgs > VT

The explanation is: For Vgs > Vt, both of the DRAIN-substrate and source-substrate will be reverse biased and hence the depletion region is NARROWER. Hence the channel is not created and hence there will be no electron FLOW from source to drain. THEREFORE the drain current will be zero.
Discussion
80.

In a small signal equivalent model of an FET, What does gm VGSstand for?(a) A pure resistor(b) Voltage controlled current source(c) Current controlled current source(d) Voltage controlled voltage sourceThis question was addressed to me in exam.This question is from The FET Small-Signal Model topic in division Field-Effect Transistors of Electronic Devices & Circuits

Answer» RIGHT answer is (b) Voltage controlled CURRENT source

For explanation I would SAY: For FET, the voltage is APPLIED across the gate and source to control the drain current, hence while writing small signal model of an FET, on the output side GM VGSrepresents a current source which can be controlled by the input voltage VGS.
Discussion
81.

For an n-channel FET, the current v at Vgs=-2V and Vds=5V was found to be 2mA, what will be the value of ID at Vgs=0V and Vds=5V?(a) 0A(b) 2mA(c) Lesser than 0A(d) Greater than 2mAI got this question during an online interview.My doubt is from The JFET Volt-Ampere Characteristics in chapter Field-Effect Transistors of Electronic Devices & Circuits

Answer»
Discussion
82.

The slope obtained in VGSvs ID was 0.002. What is the value ofgm?(a) 1(b) 2(c) 0.002(d) 0I had been asked this question during an online interview.I'd like to ask this question from The FET Small-Signal Model topic in section Field-Effect Transistors of Electronic Devices & Circuits

Answer»

The CORRECT option is (c) 0.002

The EXPLANATION is: gm = CHANGE in drain CURRENT/ change in gate to source voltagegm = slope of VGSvs IDgm = 0.002.
Discussion
83.

Find the gate to source voltage for voltage divider having R1=R2=2KΩ and VDD=12V, ID=1mA and RS=4KΩ?(a) 3V(b) 2V(c) 0V(d) 1VThis question was posed to me by my school principal while I was bunking the class.My question is based upon Biasing the FET in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer» CORRECT answer is (b) 2V

Easy explanation: VG = R2×VDD/R1+R2

=>VG=2×12/4

=>VG=6V

=>VGS=VG-ID RS

=>VGS=2V.
Discussion
84.

Voltage gain of common drain amplifier is always slightly less than _____(a) 0.5(b) 1(c) 1.5(d) 2I got this question during an online exam.The origin of the question is A Generalized FET Amplifier in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Right choice is (b) 1

For explanation I WOULD SAY: In common drain amplifier

Writing KCL at the SOURCE NODE ;

Gm(vin – vout) – gmbs vout – gds vout = 0

 vout vin = Gm / Gm + Gmbs + gds

Therefore gain is less than one.
Discussion
85.

For a self bias amplifier, RS=RD, the output will be_________________(a) Same as Input(b) Same as input but phase reversed(c) 0(d) InfiniteI had been asked this question by my college director while I was bunking the class.My doubt stems from The Common Source Amplifier topic in division Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Correct choice is (b) Same as input but phase reversed

The best I can EXPLAIN: Av=-gm RD/ (1+gm RS),

If RS=RD, Av=-gm RD/ (1+gm RD) => Avis NEARLY EQUAL to -1Av=Vo/Vi=> Vo=-Vi.
Discussion
86.

Which of the following is the necessary to hold drain current in 0 for n channel E-MOSFET?(a) Vgs > Vt(b) Vgs < Vt(c) Vgs < 2Vt(d) 2Vgs > VtThis question was posed to me by my college director while I was bunking the class.This question is from The Insulated-Gate FET(MOSFET) in section Field-Effect Transistors of Electronic Devices & Circuits

Answer»

The correct answer is (B) VGS < Vt

The explanation: For Vgs < Vt, the CHANNEL is not created and HENCE there will be no electron flow from source to drain. Therefore the drain CURRENT will be zero.
Discussion
87.

Determine the value of K (System constructor constant) for a MOSFET with Vgs=8V,Vt=2V and ID=10A?(a) 0.001A/v^2(b) 0.278 A/v^2(c) 0.5761A/v^2(d) 0.0021A/v^2This question was posed to me at a job interview.My question is taken from The Insulated-Gate FET(MOSFET) in section Field-Effect Transistors of Electronic Devices & Circuits

Answer» RIGHT CHOICE is (B) 0.278 A/v^2

Easy EXPLANATION: K=ID/(Vgs-Vt)^2

K=10/36

K=0.278.
Discussion
88.

Determine the least voltage VDS required to operate E-MOSFET on active region. (Vgs=2V,Vt=0.7V)(a) 1.2V(b) 2V(c) 0V(d) 1.3VThe question was asked during a job interview.Question is from The Insulated-Gate FET(MOSFET) in chapter Field-Effect Transistors of Electronic Devices & Circuits

Answer» RIGHT ANSWER is (d) 1.3V

To EXPLAIN: VDS=Vgs-VtVDS=2-0.7VVDS=1.3V.
Discussion
89.

What will be the value of rd, if two identical FETs are connected in parallel?(a) Doubles(b) Reduces to half(c) 0(d) InfiniteThe question was posed to me in semester exam.This question is from The JFET Volt-Ampere Characteristics topic in chapter Field-Effect Transistors of Electronic Devices & Circuits

Answer»

The correct ANSWER is (b) Reduces to half

The BEST I can explain: rd’=rd1 ×/rd1+ rd2

If rd1=rd1=rd=> then rd’=rd^2/2rd =rd/2.
Discussion
90.

For a p-channel FET, the current ID at Vgs = 2V and Vds = 5V and Vgs = 3V was found to be 2mA, what will be the value of ID at Vgs = 0V and Vds = 5V?(a) 0A(b) 2mA(c) Lesser than 0A(d) Greater than 2mAThis question was addressed to me in homework.I need to ask this question from The JFET Volt-Ampere Characteristics topic in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer» RIGHT OPTION is (a) 0A

Explanation: We know that for a p channel FET, the current will FLOW only if Vgs is lesser than Vgs, but here pinch off voltage is 3V, when Vgs=5V which is greater than pinch off voltage the channel will be DESTROYED resulting in no conventional current flow.
Discussion
91.

To use FET as a voltage controlled resistor, in which region it should operate?(a) Ohmic region(b) cut off(c) Saturation(d) cut off and saturationI had been asked this question in a national level competition.Question is taken from The Junction Field-Effect Transistor in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Right choice is (a) Ohmic region

Explanation: By VARYING the GATE to source voltage, Resistance can be varied as FOLLOWS rd = RO/(1-Vgs/Vp)^2
Discussion
92.

What is the current flowing through the R1 resistor for voltage divider (R1=R2=1KΩ, VDD=10V)?(a) 5mA(b) 3mA(c) 1mA(d) 2mAThe question was posed to me by my school principal while I was bunking the class.This interesting question is from Biasing the FET topic in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer» RIGHT answer is (a) 5mA

The BEST I can EXPLAIN: IR1=IR2 =VDD/R1+R2

=>IR1 = 10/2KΩ

=>IR1 = 5mA.
Discussion
93.

A sine signal with period 2S has a peak of 2V at 0.5S and at 1.5 it was -2V, if this signal is applied to Common drain configured amplifier, What will be the output at t=1S?(a) 2V(b) -2V(c) 0V(d) 1VThis question was posed to me in an online interview.My doubt stems from The Common Drain Amplifier topic in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Correct option is (C) 0V

The best explanation: For the given sine SIGNAL, since the period is 2S, the value of voltage at t=1S will be 0V and this signal is provided as input to COMMON drain configured AMPLIFIER which follows the input signal. Therefore the output will be 0 at t=1S.
Discussion
94.

For a self-bias circuit, find drain to source voltage if VDD=12V, ID=1mA, Rs=RD=1KΩ?(a) 1V(b) 2V(c) 10V(d) 5VThis question was posed to me in class test.Question is from Biasing the FET in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer» RIGHT ANSWER is (C) 10V

Easiest EXPLANATION: VDS=VDD-ID (RD+Rs)

=>VDS=12-1mA(1KΩ+1KΩ)

=>VDS=10V.
Discussion
95.

For a transistor in its circuit symbol, the line between drain and source was broken, what does this indicate?(a) BJT(b) JFET(c) Depletion type MOSFET(d) Enhancement type MOSFETThe question was posed to me during an internship interview.My question comes from The Insulated-Gate FET(MOSFET) topic in section Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Right option is (d) ENHANCEMENT TYPE MOSFET

The EXPLANATION: While representing a Transistor, if the solid line is broken then it represents an open SWITCH which is Enhancement type MOSFET.
Discussion
96.

Which of the following statement is true about enhancement MOSFET?(a) It acts as closed switch(b) It acts as open switch(c) It acts as resistor with small resistance(d) CapacitorThe question was posed to me in an online interview.My question is taken from The Insulated-Gate FET(MOSFET) topic in chapter Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Correct answer is (B) It acts as open switch

The BEST I can EXPLAIN: Because of an absence of channel in enhancement MOSFET, no current flows and HENCE acts as open switch.
Discussion
97.

Find the maximum value of gm for FET with IDSS=10mA, Vp=-2V, VGS=5V?(a) 10mS(b) 20mS(c) 1mS(d) 0This question was posed to me during an interview for a job.My doubt is from The FET Small-Signal Model topic in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer»

The CORRECT CHOICE is (a) 10mS

Explanation: gm0=2IDSS/|Vp|gm0=2×10mA/2Vgm0=10mS.
Discussion
98.

The effective channel length of a MOSFET in saturation decreases with increase in which of the following parameter?(a) Gate voltage(b) Drain voltage(c) Source voltage(d) Body voltageThe question was asked during an interview.Enquiry is from The Insulated-Gate FET(MOSFET) topic in chapter Field-Effect Transistors of Electronic Devices & Circuits

Answer»

Correct OPTION is (b) DRAIN VOLTAGE

Explanation: The CHANNEL length of a MOSFET in SATURATION decreases with increase in drain voltage of the MOSFET.
Discussion
99.

Which of the following is the main advantage of Self bias?(a) Eliminates the need of two power supply(b) Maximum stability(c) Minimum stability(d) Maximum & Minimum stabilityThis question was addressed to me during an online exam.Question is from The Junction Field-Effect Transistor in portion Field-Effect Transistors of Electronic Devices & Circuits

Answer» RIGHT choice is (a) Eliminates the need of two power supply

Easy explanation: SELF bias eliminates the need of 2 power supply by CONNECTING GATE resistance to the supply voltage.
Discussion
100.

Which of the following is true about n-channel E-MOSFET?(a) Electrons are the majority charge carries(b) Holes are the majority charge carries(c) Both holes and electrons are present in same ratio(d) Neutrons are the charge carriersI got this question during a job interview.My question comes from The Insulated-Gate FET(MOSFET) in section Field-Effect Transistors of Electronic Devices & Circuits

Answer»

The correct option is (a) Electrons are the MAJORITY charge carries

Explanation: n-channel E-MOSFETis designed in such a way that the source and DRAIN are formed by the n-type impurity which CONTAINS electrons as the majority charge carriers. The doping concentration of source and drain is slightly more than the GATE and body, and thus the channel created is by electrons of a source and drain.
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