VALLIAMMAI ENGINEERING COLLEGE
SRM Nagar, Kattankulathur – 603 203.
DEPARTMENT OF ELECTRONICS & COMMUNICATION ENGINEERING
QUESTION BANK
SUBJECT : EC 6202 Electronic Devices and Circuits
SEM / YEAR: III / II nd year EEE
Prepared by: N. RAJESH, AP (OG)/ECE, A. ANBARASAN, AP(OG)/ECE
EC 6202 ELECTRONIC DEVICES AND CIRCUITS
UNIT-I: PN JUNCTION DEVICES
PN junction diode –structure, operation and V-I characteristics, diffusion and transient capacitance Rectifiers – Half Wave and Full Wave Rectifier,– Display devices- LED, Laser diodes- Zener diode
characteristics-Zener Reverse characteristics – Zener as regulator
PART A
Q.NO
QUESTIONS
BT
LEVEL
DOMAIN
1.
Model diffusion capacitance in PN junction diode and explain?
BTL 3
Applying
2.
What is a rectifier? Name its types?
BTL 1
Remembering
3.
How to represent the symbol of the following
PN diode, Zener diode, LED, UJT
Find the diffusion capacitance for a silicon diode with a 15 mA forward
current, if the charge carrier transit time is 70ns.
With suitable expression what is transition capacitance and Diffusion
capacitance?
BTL 1
Remembering
BTL 1
Remembering
BTL 3
Applying
6.
Construct the laser diode and give its applications.
BTL 3
Applying
7.
Define storage time.
BTL 1
Remembering
8.
List out the factors on which barrier potential depends?
BTL 4
Analyzing
9.
Discuss the effect of temperature on reverse saturation current of a diode?
BTL6
Creating
10.
Outline transformer utilization factor and state its value for HWR and FWR?
BTL 2
Understanding
11.
Compare and contrast between p-n junction diode and zener diode?
BTL 4
Analyzing
12.
Explain the terms knee voltage and breakdown voltage?
BTL 5
Evaluating
4.
5.
EC 6202 Electronic Devices And Circuits (2016-17) Odd semester.
13.
Explain peak inverse voltage
BTL 2
Understanding
14.
Interpret the term diffusion capacitance or storage capacitance
BTL 2
Understanding
15.
Illustrate the LED symbol.
BTL 2
Understanding
16.
A silicon diode has a saturation current of 7.5 μA at room temperature to 300
°K. Estimate the saturation current at 400 ° K
BTL 6
Creating
17.
Distinguish between Zener Breakdown and Avalanche breakdown
BTL 4
Analyzing
18.
What is meant by dynamic resistance of diode?
BTL 1
Remembering
19.
A Ge diode has a saturation current of 10μA at 300ᵒ K. Determine the BTL 5
saturation current at 400ᵒK.
Show the VI characteristics of Zener diode
BTL 1
20.
Evaluating
Remembering
PART –B
1.
2.
i) Describe the action of a full wave rectifier using diodes and give waveforms
of input and output voltages
(7)
ii) Show the expression for a ripple factor in a full wave rectifier with resistive
load.
(6)
Briefly enumerate the following
i) Laser diodes
ii) Zener diode as a voltage regulator
(7+6)
BTL 1
Remembering
BTL6
Creating
3.
With neat sketch explain the construction, operation and its characteristics of
PN junction diode. Also list its advantages, disadvantages and its applications.
(13)
BTL3
Applying
4.
i) Outline the working of bridge rectifier. Give the expressions for RMS current,
PIV, Ripple factor and efficiency
(7)
ii) Illustrate the construction of LCD
(6)
i) With necessary diagrams, explain the forward and reverse characteristics of
PN junction diode
(6)
ii) Show the circuit diagram of a half wave rectifier for producing a positive
output voltage. Explain the circuit operation and sketch the waveforms.
(7)
BTL2
Understanding
BTL 1
Remembering
BTL2
Understanding
BTL5
Evaluating
BTL4
Analyzing
5.
6
7
8
i) Make use of a diagram, explain the energy band diagram of an open circuited
PN junction and obtain the expression for E0.
(8)
ii) Distinguish between Avalanche and Zener break downs
(5)
The diode current is 0.6 mA when the applied voltage is 400 mV and 20 mA
when applied voltage is 500 mV. Determine efficiency. Assume kT/q= 25mA
(13)
(i) Explain the construction and working principle of Light Emitting Diodes. (8)
(ii) The reverse saturation of a silicon PN junction diode is 10μA. Calculate the
diode current for the forward bias voltage of 0.6V at 25ᵒ
(5)
EC 6202 Electronic Devices And Circuits (2016-17) Odd semester.
9
i)Explain the effect of temperature of a diode
ii) Derive the expression for transition and diffusion capacitance
(5)
(8)
10 A germanium diode has a contact potential of .2volt while the concentration of
accepted impurity atoms is 3x10^20/m^3. Calculate for a reverse bias of .1 volt,
the width of the depletion region. If the reverse bias is increased to 10volt,
calculate the new width of the depletion region. Assuming cross sectional area
of the junction as 1mm^2 , Calculate the transition capacitance values for both
the cases. Assume Ɛr=16 for germanium
(13)
11 i)Examine the construction and working of Zener diode with a neat sketch
ii) Compare HWR with FWR
(7+6)
12 i)Draw the expression for drift current density
(5)
ii)Estimate the ideal reverse saturation current density in a silicon PN
junction at T=300K, Consider the following parameters in the silicon pn
junction. Nd=Na= 10^16cm^-3, ni= 1.5×10^10 cm^-3, Dn=25 cm2/s, Tp0=
Tn0=5×10^-7 s, Dp=10cm2/s, Ɛ r=11.7 .Comment on the result.
(8)
13
14
1.
2.
i) In an N type semiconductor, the Fermi level lies 0.3 eV below the conduction
band at 27ᵒC. If the temperature is increased to 55ᵒC, find the new position of
the Fermi level.
(7)
ii) A PN junction diode has at a temperature of 125ᵒC, a reverse saturation
current of 30μA. Find the dynamic resistance for 0.2V bias in forward and
reverse direction.
(6)
Illustrate the circuit diagram and explain the operation of full wave rectifier
using center tap transformer and using bridge rectifier without center tap
transformer. Obtain the expression for peak inverse voltage.
(13)
PART –C
An AC supply of 220V, 50 Hz is applied to a HWR through a transformer of
turn ratio 10:1. Deterrmine (i) Maximum RMS load Voltage (ii) Maximum
RMS load current (iii) Power delivered to the load (iv) AC power input (v)
Efficiency and ripple factor (vi) PIV, ripple frequency, ripple voltage and ripple
current.
(15)
A 230 V,50 Hz voltage is applied to the primary of a 5:1 stepdown centertapped transformer used in a FWR having a load of 900Ω. If the diode
resistance and the secondary coil resistance together has a resistance of 100Ω
determine, (i) DC voltage across the load (ii) DC current flowing through the
load (iii) DC power delivered to the load (iv) PIV across each diode (v) Ripple
voltage and its frequency
(15)
BTL2
Understanding
BTL4
Analyzing
BTL4
Analyzing
BTL6
Creating
BTL 1
Remembering
BTL2
Understanding
BTL 5
Evaluating
BTL 5
Evaluating
UNIT II- TRANSISTORS
BJT, JFET, MOSFET- structure, operation, characteristics and Biasing UJT, Thyristor and IGBT Structure and characteristics.
PART A
EC 6202 Electronic Devices And Circuits (2016-17) Odd semester.
Q.No
Questions
BT
Level
Domain
1.
What is base width modulation?
BTL 1
Remembering
2.
Name the two types of thyrister?
BTL 1
Remembering
3.
BTL 3
Applying
BTL 2
Understanding
5.
Solve Ic and IE for a transistor that has αdc = 0.99and IB= 150μA. Determine the
value of β dc for the transistor.
Show how an SCR can be triggered on by the application of a pulse to gate
terminal
Inspect why it is necessary to stabilize the operating point of transistor.
BTL 4
Analyzing
6.
Compare BJT and FET.
BTL 2
Understanding
7.
BTL 3
Applying
8.
Make use of the values of transistor has β=150, find the collector and base
current if IE= 10mA
Identify some applications of JFET.
BTL 3
Applying
9.
How does a transistor act as a switch?
BTL 1
Remembering
10.
Examine “thermal runaway” in transistors?
BTL 4
Analyzing
11.
Why FET is more temperature stable compared to BJT?
BTL 1
Remembering
12.
Formulate the relation between αdc and βdc?
BTL 6
Creating
13.
what is meant by biasing a transistor?
BTL 1
Remembering
14.
Contrast BJT and JFET
BTL 2
Understanding
15.
Discuss the advantages of FET over BJT
BTL 6
Creating
16.
Define amplification factor of JFET
BTL 1
Remembering
17.
Explain the intrinsic standoff ratio of a UJT?
BTL 2
Understanding
18.
Distinguish the latching current & holding current?
BTL 4
Analyzing
19.
A BJT has a base current of 200μA. Determine the collector current and β.
BTL 5
Evaluating
20.
In a n channel JFET IDSS=20 mA and VP= -6V. Estimate the drain current
when VGS= -3V.
BTL 5
Evaluating
With the help of suitable diagram, explain the working of enhancement
MOSFET
(13)
Describe the construction and working of UJT with it’s equivalent circuit and
VI characteristics.
(13)
Elaborate the construction and operation of NPN transistor with neat sketch.
Also comment on the characteristics of NPN transistor
(13)
BTL 3
Applying
BTL1
Remembering
BTL 6
Creating
With neat sketch, illustrate the construction, operation and characteristics of
BTL1
Remembering
4.
PART –B
1.
2.
3.
4.
EC 6202 Electronic Devices And Circuits (2016-17) Odd semester.
5.
SCR.
(13)
i) Enumerate the selection of Q point for transistor bias circuit and discuss the
limitations on the output voltage swing
(8)
ii) Show the cross section diagram of an N type enhancement mode MOSFET.
Briefly explain its operation
(5)
BTL1
Remembering
BTL 2
Understanding
BTL 3
Applying
BTL 5
Evaluating
BTL 2
Understanding
(5)
(8)
BTL1
Remembering
11. i) What is early effect describe with relevant expressions and figure
(6)
ii) Explain the construction and working of Ebers Moll transistor model (7)
BTL1
Remembering
12. i) Explain the structure and operation of Insulated Gate Bipoar
BTL4
Analyzing
BTL4
Analyzing
BTL4
Analyzing
6.
7.
i) Demonstrate the basic construction and equivalent circuit of a UJT. Briefly
explain the device operation
(7)
ii) Show the four layer construction of SCR and two transistor equivalent
circuit . Explain the device operation
(6)
Explain the following and derive the stability factor for each case.
a. Fixed bias
b. Collector to base bias
c. Voltage divider bias.
8.
9.
(4+4+5)
i) The reverse leakage current of the transistor when connected in CB
configuration is 0.2 mA and it is 18 μA when the same transistor is connected
in CE configuration. Determine αdc &βdc of the transistor. Assume IB =30mA.
(8)
ii) Distinguish between h-parameter and hybrid π model.
(5)
Outline the construction of N channel JFET and also explain the drain and
transfer characteristics of the same
(13)
10. i) Recall the comparisons between CE, CB and CC configurations.
ii) What are the different compensation techniques used in BJT
Transistor.
ii) Distinguish MOSFET and IGBT
13. i) Examine the various current components in a transistor.
ii) Explain the performance of FET as a voltage regulator. .
(8)
(5)
(8)
(8)
14. Take part in discussion of the two transistor model of a thyristor in detail.(13)
EC 6202 Electronic Devices And Circuits (2016-17) Odd semester.
PART –C
1. Draw d.c load line for the following transistor configuration. Obtain the
Quiescent point
(15)
BTL5
2. For the circuit shown below calculate VG, ID, VGS and VDS.
Evaluating
(15)
BTL6 Creating
UNIT-III: AMPLIFIERS
BJT small signal model – Analysis of CE, CB, CC amplifiers- Gain and frequency response –
MOSFET small signal model– Analysis of CS and Source follower – Gain and frequency response-High
frequency analysis
PART A
Q.No
Questions
BT
Level
Domain
1.
Show the hybrid model of BJT in CE configuration
BTL 1
Remembering
2.
What are amplifiers? Write it’s uses?
BTL 1
Remembering
EC 6202 Electronic Devices And Circuits (2016-17) Odd semester.
3.
Model the small signal equivalent circuit of a CS JFET
BTL 3
Applying
4.
Justify the need of coupling capacitors in amplifier design?
BTL5
Evaluating
5.
Explain the four h-parameters
BTL 4
Analyzing
6.
BTL 6
Creating
7.
For an amplifier, midband gain =100 and lower cut-off frequency is 1 kHz.
Estimate the gain of an amplifier at frequency of 20Hz.
Explain the significance of coupling and bypass capacitor on BW of amplifiers
BTL 2
Understanding
8.
Explain the term bandwidth and gain bandwidth product.
BTL5
Evaluating
9.
How can a DC equivalent circuit of an amplifier be obtained?
BTL 1
Remembering
10.
List out the different analysis available to analyze a transistor?.
BTL 1
Remembering
11.
Point out why CE configuration is preferred over CB configuration.
BTL 4
Analyzing
12.
Outline the procedure to draw the a.c. equivalent of a network
BTL 2
Understanding
13.
Identify the reason for fall in gain at low and high frequencies
BTL 3
Applying
14.
BTL 1
Remembering
15.
When transistor acts as a switch, in which regions of output characteristics it is
operated.
Discuss about thermal runaway and how it could be avoided.
BTL 6
Creating
16.
Develop the expression for pinch off voltage with respect to JFET.
BTL 3
Applying
17.
BTL 4
Analyzing
18.
When VGS of the FEET changes from -3.1V to 3V the drain voltage changes
from 1 mA to 1.3mA Calculate the value of transconductance.
Define desensitivity.
BTL 1
Remembering
19.
Show the frequency response curve of an amplifier and what is 3 dB frequency.
BTL 2
Understanding
20.
Compare the performance of CE,CB,CC amplifier configurations
BTL 2
Understanding
Illustrate the h-parameter model of a BJT-CE amplifier and derive the equations BTL 2
for voltage gain, current gain, input impedance and output impedance
(13)
2. Describe about small signal MOSFET amplifiers (NMOS) and obtain the BTL1
expression for it’s trans conductance.
(13)
3. Develop the h parameter equivalent circuit for a typical common emitter BTL3
amplifier and derive the expression for Ai, Ri, Av and Ro.
(13)
Understanding
PART –B
1.
4. i)Derive the expression for the voltage gain of CS amplifier
(5)
ii)For CS amplifier, the operating point is defined by VGSQ=-2.5V,Vp= -6V and
IdQ=2.5mA with IDSS=8mA. Also RG=1MΩ, R S=1 KΩ, R D=2.2KΩ and
VDD=15V.Calculate gm, rd, Zi, Zo and Av
(8)
Remembering
Applying
BTL3
Applying
BTL6
Creating
5. i)Discuss the factors involved in Ic, Rc and Re for a single stage common
emitter BJT amplifier circuit, using voltage divider bias
(5)
ii) A CC amplifier shown in below figure has VCC=15 V, RB=75kΩ and
EC 6202 Electronic Devices And Circuits (2016-17) Odd semester.
RE=910Ω The β of the silicon transistor is 100 and the load resistor is
600Ω. Estimate rin and Av
(8)
6. The MOSFET shown in below figure has the following parameters.
VT=2V, β=0.5×10 -3, rD=75kΩ. It is biased at ID=1.93 mA. Determine
the impedance and voltage gain (8)
BTL 5
Evaluating
BTL4
Analyzing
BTL 2
Understanding
BTL1
Remembering
BTL4
Analyzing
BTL 2
Understanding
BTL4
Analyzing
With neat circuit diagram, evaluate the ac analysis for common source
using equivalent circuit NMOSFET amplifier
(5)
7
Take part in the discussion on CB amplifier and derive the expression for h
parameters of the same. Also derive the expression for gain, input impedance
and output impedance of CB amplifier.
(13)
7. Explain
8 about CS amplifier and derive the expression for gain, input impedance
and output impedance and also draw its small signal equivalent circuit (13)
8. The hybrid parameters of a transistor used as an amplifier in the CE
configuration arehie = 800Ω, hfe = 46, hoe = 80 x 10 -6 and hre = 5.4x 10-4. If RL
= 5K and Rs =500Ω. Find Ai, Ri , Av, Pi.
(13)
9. Inspect the high frequency response of FET and derive the expression for lower
cut off frequency and upper cut off frequency
(13)
10. Demonstrate the low frequency analysis of BJT and also determine the effect of
Cs, Cc & Cc on the low frequency response of BJT
(13)
11. Explain about CC amplifier and derive the expression for h parameters of the
same. Also derive the expression for gain, input impedance and output
impedance of CC amplifier.
(13)
EC 6202 Electronic Devices And Circuits (2016-17) Odd semester.
12. What are the factors affect the bias stability of a transistor?
(8)
Define the stability factors with respect to the changes in ICO,VBE and β. Why
is the stability with respect to VCE not considered?
(5)
13. i)Show the low frequency h-equivalent model of a transistor amplifier operating
in CE mode
ii) Why is this circuit not valid for high frequencies
iii) Define the trans conductance of BJT in the CE mode. How it is related to h
parameters.
(13)
PART –C
1.
2.
BTL1
Remembering
BTL1
Remembering
BTL5
Evaluating
BTL6
Creating
Acommon collector circuit has the following components; R1=21KΩ. R 2=
27KΩ, R E=5.6 KΩ, R L=47KΩ, RS=600Ω. The transistors parameters are
hie=1KΩ, h fe=85 and hoe=2µA/V, Calculate Ai, Ri, Av, Ro, Avs and Ai=IO/IS (15)
A common base amplifier as shown in figure has the following components;
RS=600, RC=5.6K, RE=5.6K, RL=K. The transistor parameters are hie=1K,
hfe=85 and hoe=2µA/V, Calculate Ai, Ri, Av, Ro, Avs and Ai.
(15)
EC 6202 Electronic Devices And Circuits (2016-17) Odd semester.
UNIT-IV: MULTISTAGE AMPLIFIERS AND DIFFERENTIAL AMPLIFIER
BIMOS cascade amplifier, Differential amplifier – Common mode and Difference mode analysis – FET
input stages – Single tuned amplifiers – Gain and frequency response – Neutralization methods, power
amplifiers –Types (Qualitative analysis).
PART A
Q.No
Questions
BT
Level
Domain
1.
What are cascaded amplifiers?
BTL 1
Remembering
2.
BTL 3
Applying
BTL 4
Analyzing
4.
Model the ideal tuned circuits and write the expression for it’s resonant
frequency.
Explain how the differential amplifier can be used as an emitter coupled phase
inverter
Elaborate the need for neutralization?
BTL 6
Creating
5.
Identify the need for cascading the amplifiers
BTL 3
Applying
6.
What is CMRR? Examine various methods of improving CMRR.
BTL 4
Analyzing
7.
Recall the applications of differential amplifier?
BTL 1
Remembering
8.
Why neutralization is important? And give its types.
BTL 1
Remembering
9.
Construct a Differential amplifier and what is the ideal value of CMRR?
BTL 3
Applying
10.
Distinguish common mode and difference mode?
BTL 4
Analyzing
11.
Summarize the Advantages and performance of class-c amplifier
BTL 2
Understanding
12.
Explainthe term cross over distortion?
BTL 4
Analyzing
13.
BTL 2
Understanding
14.
Illustrate the ideal tuned circuit and write the expression for it’s resonant
frequency?
State Miller’s theorem
BTL1
Remembering
15.
Explain the bootstrapping technique?
BTL5
Evaluating
16.
Compare the performance of various power amplifier types.
BTL 2
Understanding
17.
Discuss need of Complementary symmetry amplifiers?
BTL 6
Creating
18.
Tell the advantages of Push pull amplifier
BTL1
Remembering
19.
Enumerate the advantages of single tuned amplifiers.
BTL1
Remembering
20.
Outline the need for constant current source for difference amplifier.
BTL 2
Understanding
3.
PART B
EC 6202 Electronic Devices And Circuits (2016-17) Odd semester.
1.
Illustrate the circuit of emitter coupled BJT differential amplifier, and derive
expressions for differential gain, common mode gain and CMRR.
(13)
What is Neutralization? Explain any one method in brief?
(13)
BTL 2
Understanding
BTL 1
Remembering
BTL 3
Applying
BTL 1
Remembering
BTL 1
Remembering
BTL 2
Understanding
BTL 3
Applying
BTL 5
Evaluating
BTL 6
Creating
10. The dual input balanced output differential amplifier having Rs=100Ω, R C
=4.7KΩ, R E =6.8KΩ,h fe=100,VCC=+15V, VEE=-15V. Find operating point
values, differential &common mode gain, CMRR and outputif Vs1=70mV(pp)at 1 kHz and Vs2=40mV(p-p)
(13)
BTL 1
Remembering
11. A Class C amplifier with VCC=25V has RL=680Ω,Cp=4300pF,Lp=20μH and
Rw=0.06Ω.The transistor has VCE(sat)=0.6V.Calculate the appropriate signal
frequency, the output power and circuit efficiency.
(13)
BTL 4
Analyzing
12. i) Draw a circuit diagram to show how the current in the output transistors of a
power amplifier can be limited to a desired maximum level. Examine the circuit
operation.
(8)
ii) Compare MOSFET to power BJT
(5)
13. Classify the power amplifiers and calculate the efficiency each types?
(13)
BTL 4
Analyzing
BTL 2
Understanding
14. Explain about Class A transformer coupled amplifier and derive the expression
for efficiency of the same.
(13)
BTL 4
Analyzing
2
3. With neat sketch explain two stage cascaded amplifier and derive its overall Av,
AI,RI and Ro
(13)
4. Show the differential amplifier and its ac equivalent circuit. Derive for Ad and
Ac.
(13)
5. With neat sketch, explain the BJT differential amplifier with active load and
derive Ad, Ac and CMRR. How CMRR can be improved
(13)
6. Explain the different types of neutralization technique used in tuning amplifier
(13)
7. Develop the equation for differential mode gain and common mode gain of a
differential amplifier.
(7+6)
8. The differential amplifier has the following values RC = 50 K, Re = 100K and
Rs = 10K. The transistor parameters are rπ = 50K= hie, hfe = Vo = 2 x10^3, ro=
400K.Determine Ad, Ac and CMRR in db.
(13)
9. i)Discuss the complementary symmetry class B amplifier and obtain its
efficiency
(7)
ii) Elaborate the operation of class AB amplifier to avoid cross over
distortion
(6)
EC 6202 Electronic Devices And Circuits (2016-17) Odd semester.
PART –C
1.
2.
Figure shows dual input, balanced output differential amplifier configuration.
Assuming silicon transistors with hie=2.5KΩ.
(15)
BTL 6
Creating
BTL 5
Evaluating
For the circuit shown below , calculate (i) Output power if the output voltage is
50 VPP (ii) Maximum ac output power (iii) DC input power if current drain is
0.5mA (iv) Efficiency if the current drain is 0.4mA and the output voltage is
30VPP. (v) Bandwidth of amplifier if Q=125 (vi) Worst case transistor power
dissipation.
(15)
UNIT-V: FEEDBACK AMPLIFIERS AND OSCILLATORS
Advantages of negative feedback – voltage / current, series, Shunt feedback –positive feedback –Condition
for oscillations, phase shift – Wien bridge, Hartley, Colpitts and Crystal oscillators.
PART A
EC 6202 Electronic Devices And Circuits (2016-17) Odd semester.
Q.No
BT
Level
Competence
Tell the disadvantages of negative feedback in amplifiers and how it can be
overcome?
Show the expression for the frequency of oscillations of a wein bridge
oscillator?
Summarize the advantages of negative feedback circuits.
BTL 1
Remembering
BTL 2
Understanding
BTL 2
Understanding
BTL 1
Remembering
BTL 1
Remembering
6.
What is the advantage of a Colpitts oscillator compared to a phase shift
oscillator?
Which is the most commonly used feedback arrangement in cascaded amplifier
and why?
Recall the Barkhausan criterion for an oscillator.
BTL 1
Remembering
7.
Identify the difference between an oscillator and amplifier?
BTL 3
Applying
8.
Name two high frequency oscillators.
BTL 1
Remembering
9.
Outline the advantages of crystal oscillator?
BTL 2
Understanding
10.
Discuss about Nyquest’s stability criteria for feedback amplifiers
BTL 6
Creating
11.
Develop the oscillator model uses both positive and negative feedback? Why?
BTL 3
Applying
12.
BTL5
Evaluating
BTL4
Analyzing
14.
Determine the operating frequency of transistor Hartley oscillator if L1=50μH,
L2=1mH, and mutual inductance between the coils M=10 μH and C=10pF.
List the five characteristics of an amplifier which are modified by negative
feedback.
Elaborate on Piezo electric effect.
BTL 6
Creating
15.
List out the advantages of crystal oscillator?
BTL 1
Remembering
16.
BTL4
Analyzing
17.
Examine the effects on bandwidth and output impedance due to various types
of feedback.
Illustrate the expression for frequency of oscillation of a Wein bridge oscillator
BTL 2
Understanding
18.
Distinguish the negative and positive feedback?
BTL4
Analyzing
19.
Identify the limitations of LC and RC oscillators
BTL3
Applying
20.
A wein bridge oscillator is used for operate at fo=10KHz. If the value of R is
100Ω. Estimate the value of capacitor.
PART-B
BTL 5
Evaluating
Illustrate the circuit of CE amplifier with current series feedback and obtain the
expression for feedback ratio, voltage gain, input and output resistances. (13)
BTL 2
Remembering
Explain the operation of Colpitts Oscillator with neat circuit diagram. Also
derive the expressions for the frequency of oscillation and the condition for
maintenance of oscillation.
(13)
BTL 2
Remembering
BTL 4
Analyzing
1.
2.
3.
4.
5.
13.
1.
2
Questions
3. Calculate Rif, Rof, Av and Avf for the following
(i)
(ii)
Voltage hunt feedback amplifier
Current series feedback amplifier
EC 6202 Electronic Devices And Circuits (2016-17) Odd semester.
(7+6)
4. Outline the following with neat diagram.
(i)
(ii)
RC phase shift oscillator.
Hartley oscillator.
(7+6)
BTL 2
Understanding
5
Make use of a circuit diagram explain the operation of the following
oscillators.
(i)
Wein bridge oscillator
(5)
(ii)
Design a Wein bridge oscillator circuit to oscillate at a
frequency of 20 kHZ.
(4)
(iii) Crystal oscillator.
(5)
BTL 3
Understanding
6
Sketch a circuit diagram of a two stage capacitor coupled BJT amplifier that
uses series voltage negative feedback. Describe how the feedback operates. (13)
BTL 1
Remembering
7
Show the circuit diagram explain the operation of an RC phase shift oscillator
and derive the condition for oscillation and resonant frequency with BJT. (13)
BTL 1
Remembering
8
Take part in the discussion of the four types of topology for feedback of an
amplifier. Derive the expression for gain with feedback. Mention the advantages
of negative feedback amplifier.
(13)
Design a Colpitts oscillator with C1 = 100pf and C2 = 7500pf. The inductance is
variable. Determine the range of inductance values, if the frequency of
oscillation is to vary between 950 KHz and 2050 KHz.
(13)
BTL 4
Analyzing
BTL6
Creating
BTL 1
Remembering
BTL 4
Analyzing
9
10 A Hartley oscillator is designed with L1 = 2mH, L2 = 20μH and a
variable capacitance. Find the range of capacitance value if the
frequency of oscillation is varied between 950 to 2050 KHZ
(13)
11 Explain the general characteristics of a negative feedback amplifier.
Represent voltage series, voltage shunt, current series and current shunt.
(13)
12
13
14
What is the condition for oscillation of a Hartley oscillator. Briefly BTL 1 Remembering
explain the operation and derive the equation for fr and hfe.
(13)
Two identical amplifier stages, each with voltage gain of 20dB and B.W
of 25kHz are cascaded. To improve gain stability the cascade is provided
BTL 5 Evaluating
with negative feedback to the extent of 10%. Estimate the effective gain
and bandwidth.
(13)
With a neat circuit diagram, describe the working of a Wien bridge
oscillator. Derive an expression for the resonant frequency. Give its
BTL 3 Understanding
advantages and disadvantages?
(13)
PART –C
1.
An amplifier has a mid frequency gain of 100 and a bandwidth of 200
kHz.
a) What will be the new bandwidth and gain if 5% negative feedback is
introduced.
EC 6202 Electronic Devices And Circuits (2016-17) Odd semester.
(b) What should be the amount of feedback, if the bandwidth is restricted
to 1 MHz.
2.
BTL 5
Evaluating
The frequency of oscillation of a Colpitts oscillator is given by
F 0=
√ (
)
Where L,C1 and C2 are the frequency determining components. Such a BTL 6 Creating
circuit operates at 450kHz with C1= C2.What will be the oscillation
frequency if the value of C2 is doubled.
EC 6202 Electronic Devices And Circuits (2016-17) Odd semester.