Download EC6202_5_UNIT_IMPORTANT_QUESTIONS_15c97 - e

OHM NAMA SIVAYA
I UNIT
PART -A
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Relate voltage & current of forward biased pn junction diode.
Calculate the speed of electron when it falls by a potential of 300 k volts.
Define static & dynamic resistance of PN diode.
What is LED? Draw it’s symbol.
What is a rectifier?
What is diffusion current?
What is a PN junction? How is it formed?
What is hole & electron in p-n junction diode?
Define ripple factor.
Compare zener breakdown & avalanche breakdown in zener diode.
Compare half wave& full wave rectifier.
Compare PN Diode & zener Diode.
Mention the application of zener diode.
Define knee voltage (or) cut –in voltage of a diode.
What is meant by depletion region?
PART-B
1. (i) Explain the VI characteristics of pn junction diode in forward & reverse bias. (8m)
(ii) Discuss the switching characteristics of pn diode.(8m)
2. (i) Explain the operation of Zener diode as voltage regulator. (OR) Discuss about zener shunt
voltage regulator.(6m)
(ii) Derive ripple factor, PIV, efficiency & TUF of bridge rectifier with circuit diagram &
input/output waveforms.(10m)
3. (i)Explain about effect of temperature of a diode .(8m)
(ii) Discuss about Drift & diffusion currents of PN diode.(8m)
4. Explain the working of a PN junction diode & Zener diode & Explain their V-I
characteristics.(16m)
5. Explain the working of center – tapped full wave rectifier (with & without filter) with neat
diagrams.(16m)
6. Draw the circuit diagram of half – wave rectifier & explain it’s operation with necessary
wave form. Also derive expression for rectification efficiency & transformer utilization
factor.(10m)
7. Explain the construction & operation of LED & Laser diode.(16m)
II UNIT
PART-A
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What are the operating modes of BJT with reference to junction biasing?
Compare BJT & MOSFET.
Draw the circuit of NPN transistor in CB configuration.
Define the Pinch – off voltage of JFET.
What is MOSFET? Name it’s types.
State the relation between α & β of a transistor.
Mention any two advantages of BJT.
What is the relation between IB ,IE ,& IC in CB configuration?
Compare JFET with BJT.
Define “Intrinsic Standoff Ratio”.
Mention the application of UJT.
Calculate β of a transistor when α=0.98. (Ans: β=0.98/(1-0.98), =4.9)
Among CE, CB, & CC configurations, which one is the most popular? Why?
PART-B
(i) Explain the input/output characteristics of BJT in common Base(CB)configuration.(10m)
(ii) Compare CE, CB, & CC configuration of BJT.(OR) Compare the performance of a
transistor in different configurations.(6m)
Explain the construction, working & static drain characteristics of Enhancement MOSFET.
(OR) With the help of suitable diagrams, explain the working of N- channel enhancement
MOSFET.(16m)
Explain the construction, working & static drain characteristics of depletionMOSFET.(16m)
Draw the circuit of NPN transistor CE configuration & describe the static input & output
characteristics.(16m)
Draw the circuit diagram & explain the working of UJT relaxation oscillator with necessary
waveforms. Also derive the expression for frequency of oscillation.(OR) Write a detailed
technical note on the following : UJT based saw tooth oscillator.(OR) Draw saw tooth
oscillator & explain its operation with its circuit diagram & output waveforms.(16m)
Explain the input/output characteristics of BJT in common Emitter (CE) configuration.
Also define active, saturation, & cut-off regions.(16m)
Explain the construction & operation of N- channel JFET with neat sketches &
characteristics curves. Also explain the three distinct regions of the output
characteristics.(16m)
A common base transistor amplifier is driven by a voltage source VS & internal resistance
RS =1200 Ω. The load impedance is a resistor RL of 1000 Ω. The ‘h’ parameters are given
below:
hib =220 Ω, hrb= 3*10^-4, hfb = -0.98, hob = 0.5µA/V.
Compute, current gain (Ai), Input impedance (Ri (or) Zi), Voltage gain AV , output
impedance (R0(or) Z0), Power gain Ap.(16m)
9. Explain the construction, working & static VI characteristics of SCR.(16m)
10. Explain the construction, working & static VI characteristics of IGBT.(16m)
III UNIT
PART-A
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What are the hybrid parameters?
Draw the hybrid small signal model of common base configuration.
Draw the hybrid model of a CE transistor.
State the advantage of h - parameters.
What is bandwidth of an amplifier?
What is roll – off?
What do you mean by half – power frequencies?
Define loading effect?
What is transconductance? Give its expression for MOSFET.
What do you mean by unity - gain frequency?
PART-B
1. (i) Obtain the hybrid model of CE (Common Emitter) transistor. (OR) Draw the small signal
model of Common Emitter transistor. & define the hybrid parameters.(8m)
2. For a CS amplifier, draw the small signal equivalent circuit & determine expression for gain,
input impedance & output impedance .(OR) Draw the small signal equivalent circuit of FET
amplifier in CS connection & derive the equations for voltage gain, input impedance &
output impedance.(16m)
3. Obtain the hybrid model of CC (Common Collector) transistor. (OR) Draw the small signal
model of Common Collector transistor. & Also derive expression for current gain, voltage
gain, input impedance, output impedance parameters.(16m)
4. Obtain the hybrid model of CB (Common Base) transistor & Also derive expression for
current gain, voltage gain, input impedance, output impedance parameters.(16m)
5. Draw & Explain the operation of frequency response of an amplifier.(8m)
6. Draw the small signal equivalent circuit of FET amplifier in CD or Source follower amplifier
connection & derive the equations for voltage gain, input impedance & output
impedance.(16m)
7. Draw & Explain the operation of high frequency response of an amplifier.
8. Derive the expression for MOSFET small signal model.
IV UNIT
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Define CMRR of differential amplifier.
State the conditions to obtain sustained oscillations in oscillator circuit?
State the advantage of BICMOS technology.
What is the need for neutralization in tuned amplifiers?
What is classification of power amplifier?
What are the advantage of differential amplifier
What do you mean by tuned amplifier?
List the methods of neutralization.
Draw equivalent circuit of single tuned amplifiers.
What are configurations of differential amplifier?
What is meant by differential amplifier?
PART-B
Derive common mode gain, differential mode gain & CMRR of differential amplifier.(16m)
Prove that Darlington Amplifier offers very high input impedance. (8m)
Draw the circuit diagram of an emitter ,coupled BJT differential amplifier & derive
expressions for of differential gain, Common mode gain ,CMRR, input impedance &
output impedance.(16m)
What is a differential amplifier & What are its Common mode & differential mode
inputs?(6m)
What do you understand by Differential amplifiers? Draw the circuit diagram & explain
the working of differential amplifier. Explain the circuit operation at CM & DM. (16m)
Draw & explain a single tuned transistor amplifier with its analysis. (16m)
Explain about the Neutralization of tuned amplifiers.(16m)
Explain the configurations of power amplifiers. (16m)
V-UNIT
PART-A
Name the types of feedback amplifiers.
Define piezo electric effect.
Mention the types of feedback amplifier connections.
Name the types of feedback amplifiers & which type of feedback amplifier is used in
oscillators.
Write the merits & demerits of RC phase shift oscillators.
List the advantages of crystal oscillator.
Compare oscillator with amplifier.
8. List the advantages of Negative feedback amplifier.
9. Define Return Ratio or Loop Gain or feedback ratio.
PART-B
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(i) Obtain expression for gain & frequency of oscillation of RC phase shift oscillator.(8m)
(ii) Write short notes on crystal oscillator. (OR) Explain the operation of crystal oscillator
with neat circuit diagram & write the expressions of its frequency of oscillations. (8m)
2. Draw the circuit of Hartley Oscillator & explain its working. Derive the expressions for
frequency of oscillation & condition for starting of oscillation. (16m)
3. Explain the general characteristics of a negative feedback amplifier : Represent
(i)Voltage – series. (ii) Voltage – shunt. (iii) Current – series & (iv) current shunt feedback
connections diagrammatically. (16m)
4. Explain the effects of negative feedback amplifiers.(10m)
5. Draw the circuit diagram & explain the principle of operation of the following
oscillators: (i) RC phase shift oscillator.
(ii) Any one LC oscillator. (Hartley oscillators, Colpitts oscillators). (16m)