SEM- 4th Semester – B.E. / B.Tech.

BR- Electronics and Communication Engineering

EC6401 Electronic Circuit - II

Part-A (10 x 2 = 20 Marks)

UNIT – I

No Question Leve

l

Competence Mar

k

1.1 Define positive and negative feedback. L 1 Remember 2

1.2 List out the three networks that are connected around the basic

amplifier to implement feedback concept.

L 1 Remember 2

1.3 Define sensitivity and de-sensitivity of gain in feedback amplifiers. L 1 Remember 2

1.4 Examine the gain with feedback for the amplifier with open loop

gain of 300 and feedback factor of 0.1.

L 1 Remember 2

1.5 Tabulate the input and output resistances of a negative feedback

amplifier.

L 1 Remember 2

1.6 Define positive and negative feedback. L 1 Remember 2

1.7 Predict the loop gain or return ratio of feedback amplifier. L 2 Understand 2

1.8 Discuss the advantages of negative feedback in amplifiers. L 2 Understand 2

1.9 Express the reason for negative feedback which increases

bandwidth.

L 2 Understand 2

2.1 Describe the effect of gain in amplifier when voltage shunt &

series feedback is employed.

L 2 Understand 2

2.2 Discover the impact of negative feedback on noise and distortion

in amplifier circuits

L 3 Apply 2

Nadar Saraswathi College of Engineering and Technology,

Vadapudupatti, Theni - 625 531

(Approved by AICTE, New Delhi and Affiliated to Anna University, Chennai)

Format No. NAC/TLP-

07a.12

Rev. No. 01

Date 14-11-2017

Total Pages 01

Question Bank for the Units – I to V

2.3 Calculate the percentage of negative feedback if a feedback is used

to reduce the distortion of an amplifier by 80 %. The voltage gain

of the amplifier is 150.

L 3 Apply

2

2.4 Illustrate the current series & current shunt feedback. L 3 Apply 2

2.5 Analyze the feedback factor of an amplifier. L 4 Analyze 2

2.6 Differentiate Phase margin and Gain margin. L 4 Analyze 2

2.7 Explain the decrease in output impedance in feedback amplifiers. L 4 Analyze 2

2.8 Summarize the effect of negative feedback on amplifier

characteristics.

L 5 Evaluate 2

2.9 Create the equivalent circuit of Trans-conductance amplifier. L 6 Create 2

2.10 Compose the stability condition using Nyquist criterion. L 6 Create 2

UNIT - II

3.1 Define an oscillator and show why the oscillator is called as

sinusoidal or harmonic oscillator?

L 1 Remember 2

3.2 Recall amplifier and oscillator. L 1 Remember 2

3.3 State the Barkhausen criterion for an oscillator. L 1 Remember 2

3.4 Group the Oscillator classification by their frequency generated. L 1 Remember 2

3.5 Write the general equation for an oscillator. L 1 Remember 2

3.6 Draw the block diagram of an oscillator. L 1 Remember 2

3.7 Outline the equivalent circuit of an oscillator. L 2 Understanding 2

3.8 Observe LC oscillator. L 2 Understanding 2

3.9 Compare Hartley and Colpitts oscillator. L 2 Understanding 2

3.10 If L1 = 1 mH, L2 = 2 mH and C = 0.1 nF, Observe the frequency

of oscillation for Hartley oscillator.

L 2 Understanding 2

4.1 A Colpitts Oscillator circuit having two capacitors of 24nF and

240nF respectively are connected in parallel with an inductor

of 10mH. Identify the frequency of oscillations of the circuit,

the feedback fraction.

L 3 Applying

2

4.2 Interpret how the feedback occurs in Armstrong Oscillator? L 3 Applying 2

4.3 Choose the advantages of RC phase shift oscillator. L 3 Applying 2

4.4 In an RC phase shift oscillator, if R1 = R2 = R3 = 200kΩ and C1

= C2 = C3 = 100 pF. Detect the frequency of oscillations.

L 4 Analyzing 2

4.5 Analyze the advantages and disadvantages of wein bridge

oscillator.

L 4 Analyzing 2

4.6 Inspect the advantages of crystal oscillator. L 4 Analyzing 2

4.7 Tell about the quartz crystal and draw the equivalent circuit of

and mention its series and parallel resonant frequencies.

L 5 Evaluating 2

4.8 Determine piezoelectric effect. L 5 Evaluating 2

4.9 Compose the figure of X-cut & Y-cut of Piezo-electric crystal. L 6 Creating 2

4.10 Predict the factors which contribute to change in frequency. L 6 Creating 2

UNIT – III

5.1 Tell the advantages and disadvantages of tuned amplifier L 1 Remember 2

5.2 Identify the ideal response and actual response of tuned amplifiers

with diagram.

L 1 Remember 2

5.3 Define stagger tuned amplifier L 1 Remember 2

5.4 Where the Q point is placed in a class C amplifier? L 1 Remember 2

5.5 List the performance measure of tuned amplifier. L 1 Remember 2

5.6 Define gain product bandwidth of tuned amplifier. L 1 Remember 2

5.7 Summarize the effect of cascading n stages of identical single

tuned amplifiers on bandwidth

L 2 Understand 2

5.8 Estimate the bandwidth of a 3 stage cascaded single tuned

amplifier if the resonant frequency is 455 KHz and the loaded Q

of each stage is 10.

L 2 Understand

2

5.9 Express the need for neutralization. L 2 Understand 2

5.10 Give the applications of class C tuned amplifier. L 2 Understand 2

6.1 Illustrate the applications of tuned amplifiers. L 3 Apply 2

6.2 A tuned amplifier has its maximum gain at a frequency of 2

MHz and has a bandwidth of 50 KHz. Calculate the Q factor

L 3 Apply 2

6.3 Examine the efficiency of class C tuned amplifier. L 3 Apply 2

6.4 Differentiate loaded Q and unloaded Q. L 4 Analyze 2

6.5 Compare single tuned and synchronously tuned amplifiers. L 4 Evaluate 2

6.6 Classify tuned amplifier L 4 Create 2

6.7 Discriminate Hazeltine and modified Hazeltine neutralization. L 5 Evaluate 2

6.8 Deduce the magnitude of stagger tuned amplifier. L 5 Evaluate 2

6.9 An inductor of 250 µH has Q = 300 at 1MHz. Invent Rs and Rp

of the inductor.

L 6 Create 2

6.10 Create the equivalent circuit of neutralization L 6 Create 2

UNIT-IV

7.1 Define linear wave shaping circuits. L 1 Remember 2

7.2 What is high pass filter? L 1 Remember 2

7.3 Recall duty cycle. L 1 Remember 2

7.4 Tell the rise time and storage time of a transistor switching circuit. L 1 Remember 2

7.5 Write about clipper and sort its main types. L 1 Remember 2

7.6 Describe a simple clamper circuit. L 1 Remember 2

7.7 Outline the applications of astable multivibrator. L 2 Understand 2

7.8 In the astable multivibrator, R1=R2=R=10kΩ and C1=C2=0.01µf.

Show the time period and frequency of the square wave.

L 2 Understand 2

7.9 Summarize the applications of bistable multivibrator. L 2 Understand 2

7.10 Illustrate how the diode act as a comparator? L 2 Understand 2

8.1 Discover the role of commutating capacitor and draw its circuit. L 3 Applying 2

8.2 Examine whether the “tilt” applicable to RC circuits? Give an

expression for tilt.

L 3 Applying 2

8.3 Calculate the value of capacitors to be used in an astable

multivibrator to provide a train of pulse 2 µsec wide at a

repetition rate of 75 KHz with R1=R2=10 KΩ.

L 3 Applying

2

8.4 Identify how the high pass RC circuit acts as a differentiator. L 4 Analyze 2

8.5 Compare Astable, Monostable and Bistable multivibrators. L 4 Analyze 2

8.6 Pointout UTP & LTP in Schmitt trigger. L 4 Analyze 2

8.7 Differentiate symmetrical triggering and unsymmetrical

triggering.

L 5 Evaluate 2

8.8 Predict the operation of differentiator. L 5 Evaluate 2

8.9 Design the circuit of RC integrator and mention the condition

under which the circuit behaves as an integrator.

L 6 Create 2

8.10 Develop a clipper circuit which clips all voltages above +2 V. L 6 Create 2

UNIT- V

9.1 When the oscillator is called as a free running blocking oscillator? L 1 Remember 2

9.2 Tell the advantage of core saturation method of frequency control

in a blocking oscillator.

L 1 Remember 2

9.3 List any two methods of achieving sweep linearity of a time- base

waveform.

L 1 Remember 2

9.4 Define duty cycle. L 1 Remember 2

9.5 Recall the concept of Sweep time. L 1 Remember 2

9.6 Describe the operation of UJT L 1 Remember 2

9.7 Give the two important elements of blocking oscillator. L 2 Understand 2

9.8 Differentiate „restoration time‟ and „sweep time‟ of a time- base

signal.

L 2 Understand 2

9.9 Mention the various elements of pulse transformer. L 2 Understand 2

9.10 Summarize applications of the pulse transformer. L 2 Understand 2

10.1 Show the characteristics of pulse transformer. L 3 Apply 2

10.2 Write the equation used to determine sweep frequency of a UJT

relaxation oscillator. Calculate the frequency with R = 100 KΩ, C

= 0.4 µF and intrinsic stand-off ratio 0.57.

L 3 Apply

2

10.3 Illustrate the slope error of a voltage sweep waveform. L 3 Apply 2

10.4 Classify the voltage and current time base generators. L 4 Analyze 2

10.5 Compare sweep speed error and transmission error. L 4 Analyze 2

10.6 Analyze the restoration time or flyback time L 4 Analyze 2

10.7 Judge the function of time base circuit. L 5 Evaluate 2

10.8 Conclude the applications of blocking oscillator. L 5 Evaluate 2

10.9 Design a complete equivalent circuit of pulse transformer. L 6 Create 2

10.10 Develop the equivalent circuit of UJT. L 6 Create 2

Part – B ( 5 x 16 = 80 Marks) or Part – B ( 5 X 13 = 65 Marks)

UNIT- I

11.a-1 Derive the expressions for gain with positive and negative

feedback

L6 Create 13

11.a-2 What is the effect of negative feedback on stability,

distortion, noise, input and output impedance of a feedback

amplifier?

L1 Remember 13

11.a-3 What is the effect of a voltage series feedback on input and output

resistance of a BJT amplifier? Explain the same, with necessary

circuit, equivalent circuit and equations

L2 Understand 13

11.a-4 Draw the circuit diagram of voltage shunt feedback

amplifier and derive the expressions for Rif and Rof.

L3 Apply 13

11.b-1 With an example Circuit of current series feedback and derive

the expressions for Rif and Rof.

L5 Evaluate 13

11.b-2 Explain the current shunt feedback connection and derive the

expressions for Rif and Rof.

L4 Analyze 13

11.b-3 Explain Nyquist criterion to analyze the stability of feedback

amplifiers.

L4 Analyze 13

UNIT – II

12.a-1 Briefly describe the general condition for oscillation for a LC

oscillator and derive the frequency of oscillation for a colpitts

oscillator.

L1 Remember

13

12.a-2 Estimate the frequency of oscillation and the condition for

sustained Hartley oscillator

L2 Understand 13

12.a-3 Identify the general form of an LC oscillator and derive

the

equations with the diagrams and its equivalent

circuit.

L1 Remember 13

12.a-4 With neat circuit diagrams explain the working principle of the

following:

i. Tuned collector oscillator

ii. ii. Franklin oscillator

iii. Armstrong oscillator

L6 Create

(7)

(6)

12.b-1 What is a Wien Bridge? How is it used as an

oscillator? Derive the necessary equations.

L5 Evaluate 13

12.b-2 Demonstrate the working principle of RC phase shift oscillator

circuit diagram also derive the expression for frequency

of oscillation and condition for sustained oscillation.

L3 Apply 13

12.b-3 Analyze the working of Miller and Pierce crystal oscillators

with neat circuit diagrams. Give two applications.

L4 Analyze 13

UNIT - III

13.a-1 Explain the Q factor for inductor. L2 Understand 13

13.a-2 Draw the circuit diagram and equivalent circuit of capacitor

coupled single tuned amplifier and derive the expression for 3 –

dB bandwidth. Sketch also the frequency response of the

amplifier.

L4 Analyze 13

13.a-3 With neat circuit diagram explain double tuned amplifier and

derive the expression for 3 – dB bandwidth. Sketch also the

frequency response of the amplifier.

L6 Create 13

13.b-1 Draw the circuit diagram of a two-stage synchronously tuned

amplifier and also its equivalent circuit. Derive the expression for

bandwidth

L1 Remember 13

13.b-2 Explain class C tuned amplifier and derive its efficiency. Also

discuss about its frequency response.

L2 Understand 13

13.b-3 Explain the following with neat circuit diagram:

i. Hazeltine neutralization

ii. Neutrodyne neutralization

L2 Understand 7

8

13.b-4 Describe the principles involved in stagger tuned amplifier. L2 Understand

13

UNIT -IV

14.a-1 How the RC Low pass filter will response by applying square wave,

symmetrical square wave and ramp input signal?

L1 Remember 13

14.a-2 a) Classify the various types of diode clippers. (b)

Demonstrate the diode clippers with appropriate diagrams and

waveforms.

L3 Apply 13

14.a-3 With neat Diagram a transistor switching circuit and its

response waveform for a pulse input. For such a circuit,

explain the following terms:

L1Delay time L2 Turn on time L3 Storage time L4Fall time and

L5Turn-off time

L6 Create 13

14.a-4 Examine the working principle of modified astable multivibrator

and emitter coupled astable multivibrator with diagrams.

L4 Analyze 13

14.b-1 Briefly discuss about the one shot multivibrator with

neat circuit diagrams and waveforms. Derive the

expression and mention its advantages and disadvantages.

L2 Understand

(13)

14.b-2 Evaluate the working principle of Bistable multivibrator with

neat diagrams.

L5 Evaluate 13

14.b-3 Explain the different types of triggering used for bistable

multivibrator.

L2 Understand 13

14.b-4 (a) Determine how Schmitt trigger circuit can be evolved from a

bistable circuit.

(b) Formulate the expression for UTP and LTP in Schmitt

trigger with circuit diagrams.

L5 Evaluate (6)

(7)

UNIT V

15.a-1 Describe the operation of a RC controlled astable transistor

blocking oscillator with circuit diagram and waveforms.

L1 Remember 13

15.a-2 How does an Astable circuit acts as a free running

blocking oscillator? Draw the circuit and explain.

L5 Evaluate 13

15.a-3 Compare RC controlled and Diode controlled Astable blocking

oscillator.

L6 Create 13

15.a-4 Describe the operation of a triggered blocking oscillator with

emitter timing.Sketch the circuit and waveforms and also derive

L2 Understand

13

the expression for tp

15.b-1 The diode controlled Astable blocking oscillator has the

parameters Vc = 10 V, Vb= 5 V, C1 = C2 = 2 nF, Vr = 9V, L = 3

mH and C = 100 pF. Calculate the frequency of oscillation and

duty cycle.

L4 Analyze 13

15.b-2 Illustrate the working of UJT (saw tooth generator) with

suitable circuit and waveforms & explain.

L4 Analyze 13

15.b-3 Design the circuit of Bootstrap voltage time base generator and

explain the quiescent conditions, formation of sweep,

retrace interval and recovery process.

L6 Create 13

15.b-4 Summarize Miller integrator and current time-base circuit

waveforms.

L2 Understand 13

Part – C ( 1 x 15 = 15 Marks)

UNIT-1

16 .a-

1

An amplifier, without feedback, has a voltage gain of 500, lower

cut-off frequency f1= 100 Hz, upper cut-off frequency f2 = 250

KHz and a distortion of 10%. Determine the amplifier voltage

gain, lower cut-off frequency and upper cut-off frequency and

distortion, when a negative feedback is applied with feedback

ratio of 0.0L1

L4 Analyze

15

16 .a-

2

(i) Estimate Nyquist criterion to analyze the stability of feedback

amplifiers (8) (ii)

Propose the expressions for gain with positive and negative

feedback

L6 Create

15

(OR)

16.b-1 Explain the effect of series-shunt feedback on output resistance L5 Evaluate 15

16.b-2 Recall all the parameters of negative feedback circuits . L1 Remember 15

UNIT-2

16 .a-

1

Write the any one type of tank circuit oscillator L1 Remember 15

16 .a-

2

Design the Capacitor C and hfe for the transistor to provide a

resonating frequency of 10kHz of a transistorized phase shift

oscillator. Assume R1=25kΩ, R2=60kΩ, Rc=40kΩ, R=7.1kΩ and

hfe

=1.8kΩ.

L6 Create

15

(OR)

16.b-1 Explain the basic structure and basic operation of precious stone

oscillator

L2

Understand

15

16.b-2 Elaborate the working of Colpitts crystal oscillator with quartz

crystal construction and with appropriate diagrams.

L5 Evaluate 15

UNIT-3

16 .a-

1

(i) Explain single tuned amplifier and derive for gain, resonant

frequency and cut-off frequencies. (10)

(ii) Opinion on class –C tuned amplifier (5)

L5 Evaluate 10

5

16 .a-

2

Write the small frequency oscillator with neat diagram L1 Remember 15

(OR)

16.b-1 Discuss about synchronous tuned amplifiers. Draw the circuit of a

two stage capacitor coupled single tuned amplifier and explain with

equations the effect of cascading on the gain and bandwidth

L6 Create

15

16.b-2 Explain with neat circuit diagram:

i. Hazeltine neutralization

ii. Neutrodyne neutralization

L2

Understand 8

7

UNIT-4

16 .a-

1

Construct one shot multivibrator with necessary circuit diagrams

and waveforms.

L6

CREATE

15

16 .a-

2

Design a Schmitt trigger circuit for the data given: Vcc = 20, UTP

= 5V and LTP= 3 V. Ic sat = 2 mA and hfe ( min) = 100. Draw the

designed circuit.

L4

Analyze

15

(OR)

16.b-1 Draw and explain the mono stable multivibrator L2

Understand

15

16.b-2 (a) Develop the high pass RL Circuit with necessary diagrams.

(b) Design low pass RL circuits with necessary diagrams

and expressions.

L5 Evaluate 7

8

UNIT-5

16 .a-

1

Summarize the circuit diagram and operation of monostable

blocking oscillator with base timing and emitter timing.

L5

Evaluate

15

16 .a-

2

For a certain UJT sweep circuit, the resistance is 20 KΩ while

the capacitance is 0.2 µ F. The valley potential is L15 V when VBB

= 15 V. Assuming diode cut in voltage of 0.7 V and intrinsic stand-

off ratio as 0.5, calculate the frequency of oscillations.

L4

Analyze 15

(OR)

16.b-1 Explain the operation of any onr blocking oscillators with neat

diagram.

L5 Evaluate 15

16.b-2 Explain the any one type of free running oscillator L2 Understand 15

L1: Knowledge/Remembering , L2: Comprehension/Understanding , L3: Application,

L4: Analysis, L5: Evaluation, L6: Synthesis/ Create

QUESTION BANK SUMMARY

S.NO UNIT DETAILS L1 L2 L3 L4 L5 L6 TOTAL

1 Unit-1

PART-A 6 4 3 3 1 2 19

PART-B 1 1 1 2 1 1 7

PART-C 1 0 0 1 1 1 4

2 Unit-2

PART-A 6 4 3 3 2 2 20

PART-B 2 1 1 1 1 1 7

PART-C 1 1 0 0 1 1 4

3 Unit-3

PART-A 6 4 3 3 2 2 20

PART-B 1 4 0 1 0 1 7

PART-C 1 1 0 0 1 1 4

4 Unit-4

PART-A 6 4 3 3 2 2 20

PART-B 1 2 1 1 2 1 8

PART-C 0 1 0 1 1 1 4

5 Unit-5

PART-A 6 4 3 3 2 2 20

PART-B 1 2 0 2 1 2 8

PART-C 0 1 0 1 2 0 4

Total No of Questions

PART-A PART-B PART-C TOTAL

99 37 20 156

Prepared By:

Staff Name1: B.MAHESH AP/ECE

Staff Name2:

STAFF IN CHARGE HOD PRINCIPAL