STUDENT OBSERVATION MANUAL - vemu.orgvemu.org/uploads/lecture_notes/20_01_2020_1218425987.pdf · viva voce (10m) attendan ce (10m) 1 voltage series feedback amplifier 2 two stage

ELECTRONIC CIRCUIT ANALYSIS LAB

II/IV B. TECH., II SEMESTER

STUDENT OBSERVATION MANUAL

DEPARTMENT

OF

ELECTRONICS & COMMUNICATION ENGINEERING

VEMU INSTITUTE OF TECHNOLOGY Tirupati - Chittoor Highway Road, P. Kothakota, Chittoor- 517 112.

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY ANANTAPUR

VEMU INSTITUTE OF TECHNOLOGY

DEPT. OF ELECTRONICS AND COMMUNICATION ENGINEERING

Vision of the institute

To be a premier institute for professional education producing dynamic and vibrant force of

technocrat with competent skills, innovative ideas and leadership qualities to serve the society

with ethical and benevolent approach.

Mission of the institute

Mission_1: To create a learning environment with state-of-the art infrastructure, well equipped

laboratories, research facilities and qualified senior faculty to impart high quality technical

education.

Mission_2: To facilitate the learners to foster innovative ideas, inculcate competent research and

consultancy skills through Industry-Institute Interaction.

Mission_3: To develop hard work, honesty, leadership qualities and sense of direction in rural

youth by providing value based education.

Vision of the Department

To become a centre of excellence in the field of Electronics and Communication Engineering

and produce graduates with Technical Skills, Research & Consultancy Competencies, Life-long

Learning and Professional Ethics to meet the challenges of the Industry and Society.

Mission of the Department

Mission_1: To enrich Technical Skills of students through Effective Teaching and Learning

practices for exchange of ideas and dissemination of knowledge.

Mission_2: To enable the students with research and consultancy skill sets through state-of-the

art laboratories, industry interaction and training on core & multidisciplinary technologies.

Mission_3: To develop and instill creative thinking, Life-long learning, leadership qualities,

Professional Ethics and social responsibilities among students by providing value based

education.

Programme Educational Objectives ( PEOs)

PEO_1: To prepare the graduates to be able to plan, analyze and provide innovative ideas to

investigate complex engineering problems of industry in the field of Electronics and

Communication Engineering using contemporary design and simulation tools.

PEO_2: To provide students with solid fundamentals in core and multidisciplinary domain for

successful implementation of engineering products and also to pursue higher studies.

PEO_3: To inculcate learners with professional and ethical attitude, effective communication

skills, teamwork skills, and an ability to relate engineering issues to broader social context at

work place.

Programme Outcome (POs)

PO_1: Engineering knowledge: Apply the knowledge of mathematics, science, engineering

fundamentals, and an engineering specialization to the solution of complex engineering

problems.

PO_2: Problem analysis: Identify, formulate, review research literature, and analyze complex

engineering problems reaching substantiated conclusions using first principles of mathematics,

natural sciences, and engineering sciences.

PO_3: Design/development of solutions: Design solutions for complex engineering problems

and design system components or processes that meet the specified needs with appropriate

consideration for the public health and safety, and the cultural, societal, and environmental

considerations.

PO_4: Conduct investigations of complex problems: Use research-based knowledge and

research methods including design of experiments, analysis and interpretation of data, and

synthesis of the information to provide valid conclusions.

PO_5: Modern tool usage: Create, select, and apply appropriate techniques, resources, and

modern engineering and IT tools including prediction and modeling to complex engineering

activities with an understanding of the limitations.

PO_6: The engineer and society: Apply reasoning informed by the contextual knowledge to

assess societal, health, safety, legal and cultural issues and the consequent responsibilities

relevant to the professional engineering practice.

PO_7: Environment and sustainability: Understand the impact of the professional engineering

solutions in societal and environmental contexts, and demonstrate the knowledge of, and need

for sustainable development.

PO_8: Ethics: Apply ethical principles and commit to professional ethics and responsibilities

and norms of the engineering practice.

PO_9: Individual and team work: Function effectively as an individual, and as a member or

leader in diverse teams, and in multidisciplinary settings.

PO_10: Communication: Communicate effectively on complex engineering activities with the

engineering community and with society at large, such as, being able to comprehend and write

effective reports and design documentation, make effective presentations, and give and receive

clear instructions.

PO_11: Project management and finance: Demonstrate knowledge and understanding of the

engineering and management principles and apply these to one’s own work, as a member and

leader in a team, to manage projects and in multidisciplinary environments.

PO_12: Life-long learning: Recognize the need for, and have the preparation and ability to

engage in independent and life-long learning in the broadest context of technological change.

Programme Specific Outcome (PSOs)

PSO_1: Higher Education: Qualify in competitive examinations for pursuing higher education

by applying the fundamental concepts of Electronics and Communication Engineering domains

such as Analog & Digital Electronics, Signal Processing, Communication & Networking,

Embedded Systems, VLSI Design and Control Systems etc..

PSO_2: Employment: Get employed in allied industries through their proficiency in program

specific domain knowledge, specialized software packages and Computer programming or

become an entrepreneur.

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY ANANTAPUR

Electronics and Communication Engineering

II B.Tech II-Sem (E.C.E) L C

4 2

(15A04404) ELECTRONIC CIRCUIT ANALYSIS LABORATORY

Course Outcomes:

C227.1: Analyze the single and multistage amplifiers at low, mid and high frequencies using

simulation software and Hardware.

C227.2: Analyze the transistor oscillators using simulation software and Hardware.

C227.3: Determine the efficiencies of power amplifiers using simulation software and Hardware.

C227.4: Determine Frequency response and design of tuned amplifiers using simulation software

and Hardware.

PART A: List of Experiments :( Minimum of Ten Experiments has to be performed)

1. Determination of fT of a given transistor.

2. Voltage-Series Feedback Amplifier

3. Current-Shunt Feedback Amplifier

4. RC Phase Shift/Wien Bridge Oscillator 5. Hartley/Colpitt’s Oscillator

6. Two Stage RC Coupled Amplifier

7. Darlington Pair Amplifier 8. Bootstrapped Emitter Follower

9. Class A Series-fed Power Amplifier

10. Transformer-coupled Class A Power Amplifier

11. Class B Push-Pull Power Amplifier 12. Complementary Symmetry Class B Push-Pull Power Amplifier

13. Single Tuned Voltage Amplifier

14. Double Tuned Voltage Amplifier

PART B: Equipment required for Laboratory

Software:

i. Multisim/ Pspice/Equivalent Licensed simulation software tool

ii. Computer Systems with required specifications

Hardware:

1. Regulated Power supplies

2. Analog/Digital Storage Oscilloscopes

3. Analog/Digital Function Generators

4. Digital Multimeters 5. Decade Résistance Boxes/Rheostats

6. Decade Capacitance Boxes

7. Ammeters (Analog or Digital) 8. Voltmeters (Analog or Digital)

9. Active & Passive Electronic Components

10. Bread Boards 11. Connecting Wires

12. CRO Probes etc.

VEMU INSTITUTE OF TECHNOLOGY::P.KOTHAKOTA NEAR PAKALA, CHITTOOR-517112

(Approved by AICTE, New Delhi & Affiliated to JNTUA, Anantapuramu) Department of Electronics &Communication Engineering

LIST OF EXPERIMENTS TO BE CONDUCTED

PART A: List of Experiments (Software)

1. Voltage-Series Feedback Amplifier

2. Current-Shunt Feedback Amplifier

3. RC Phase Shift/Wien Bridge Oscillator 4. Hartley/Colpitt’s Oscillator

5. Two Stage RC Coupled Amplifier

6. Darlington Pair Amplifier

7. Class A Series-fed Power Amplifier 8. Class B Push-Pull Power Amplifier

9. Complementary Symmetry Class B Push-Pull Power Amplifier


PART B: List of Experiments (Hardware)

1. Voltage-Series Feedback Amplifier 2. Current-Shunt Feedback Amplifier

3. RC Phase Shift/Wien Bridge Oscillator

4. Hartley/Colpitt’s Oscillator

5. Two Stage RC Coupled Amplifier 6. Darlington Pair Amplifier

7. Class A Series-fed Power Amplifier

8. Class B Push-Pull Power Amplifier 9. Complementary Symmetry Class B Push-Pull Power Amplifier


PART C: ADVANCED EXPERIMENTS

1. Source Follower with Bootstrapped Circuit

2. Fixed bias amplifier circuit using BJT

CONTENTS

S.NO. NAME OF THE EXPERIMENT PAGE

NO

SIMULATION EXPERIMETS

1 VOLTAGE SERIES FEEDBACK AMPLIFIER 1-4

2 TWO STAGE RC COUPLED AMPLIFIER 5-8

3(a) RC PHASE SHIFT OSCILLATOR 9-12

3(b) WEIN BRIDGE OSCILLATOR 13-16

4 CLASS A AMPLIFIER 17-20

5(a) COLPITT’S OSCILLATOR 21-24

5(b) HARTLEY OSCILLATOR 25-28

6 DARLINGTON PAIR 20-32

7 SINGLE TUNED VOLTAGE AMPLIFIER 33-36

8 CURRENT SHUNT FEEDBACK AMPLIFIER 37-40

9 CLASS B PUSH PULL AMPLIFIER 41-44

10 CLASS B COMPLEMENTARY SYMMETRY AMPLIFIER 45-48

HARDWARE EXPERIMETS

1 VOLTAGE SERIES FEEDBACK AMPLIFIER 49-52

2 TWO STAGE RC COUPLED AMPLIFIER 53-56

3 SINGLE TUNED VOLTAGE AMPLIFIER 57-60

4(a) COLPITT’S OSCILLATOR 61-64

4(b) HARTLEY OSCILLATOR 65-68

5 DARLINGTON PAIR 69-72

6(a) RC PHASE SHIFT OSCILLATOR 73-77

6(b) WEIN BRIDGE OSCILLATOR 78-81

7 CLASS A AMPLIFIER 82-84

8 CURRENT SHUNT FEEDBACK AMPLIFIER 85-88

9 CLASS B PUSH PULL AMPLIFIER 89-92

10 CLASS B COMPLEMENTARY SYMMETRY AMPLIFIER 93-96

ADVANCED EXPERIMENTS

1 SOURCE FOLLOWER WITH BOOTSTRAPPED CIRCUIT

98-101

2 FIXED BIAS AMPLIFIER CIRCUIT USING BJT

102-104

DOS & DONTS IN LABORATORY

1. While entering the Laboratory, the students should follow the dress code (Wear

shoes, White Apron & Female students should tie their hair back).

2. The students should bring their observation note book, practical manual, record

note book, calculator, necessary stationary items and graph sheets if any for the

lab classes without which the students will not be allowed for doing the

practical.

3. All the equipments and components should be handled with utmost care. Any

breakage/damage will be charged.

4. If any damage/breakage is noticed, it should be reported to the instructor

immediately.

5. If a student notices any short circuits, improper wiring and unusual smells

immediately the same thing is to be brought to the notice of technician/lab in

charge.

6. At the end of practical class the apparatus should be returned to the lab

technician and take back the indent slip.

7. Each experiment after completion should be written in the observation note

book and should be corrected by the lab in charge on the same day of the

practical class.

8. Each experiment should be written in the record note book only after getting

signature from the lab in charge in the observation note book.

9. Record should be submitted in the successive lab session after completion of the

experiment.

10. 100% attendance should be maintained for the practical classes.

SCHEME OF EVALUVATION

S No Date Name of Experiment

Marks Awarded

Total

(30M) Record

(10M)

Observation

(10M)

Viva

Voce

(10M)

Attendance

(10M)

1 VOLTAGE SERIES

FEEDBACK AMPLIFIER

2 TWO STAGE RC

COUPLED AMPLIFIER

3(a) RC PHASE SHIFT

OSCILLATOR

3(b) WEIN BRIDGE

OSCILLATOR

4 CLASS A AMPLIFIER

5(a) COLPITT’S OSCILLATOR

5(b) HARTLEY OSCILLATOR

6 DARLINGTON PAIR

7 SINGLE TUNED

VOLTAGE AMPLIFIER

8 CURRENT SHUNT

FEEDBACK AMPLIFIER

9 CLASS B PUSH PULL

AMPLIFIER

10 CLASS B

COMPLEMENTARY

SYMMETRY AMPLIFIER

Signature of Lab In-charge

SCHEME OF EVALUVATION

S NO DATE NAME OF EXPERIMENT

MARKS AWARDED

TOTAL

(30M) Record

(10M)

Observation

(10M)

Viva

voce

(10M)

Attendan

ce (10M)

1 VOLTAGE SERIES

FEEDBACK AMPLIFIER

2 TWO STAGE RC COUPLED

AMPLIFIER

3 SINGLE TUNED VOLTAGE

AMPLIFIER

4(a) COLPITT’S OSCILLATOR

4(b) HARTLEY OSCILLATOR

5 DARLINGTON PAIR

6(a) RC PHASE SHIFT

OSCILLATOR

6(b) WEIN BRIDGE OSCILLATOR

7 CLASS A AMPLIFIER

8 CURRENT SHUNT

FEEDBACK AMPLIFIER

9 CLASS B PUSH PULL

AMPLIFIER

10 CLASS B COMPLEMENTARY

SYMMETRY AMPLIFIER

ADVANCED EXPERIMENTS

1

SOURCE FOLLOWER WITH

BOOTSTRAPPED CIRCUIT

2

FIXED BIAS AMPLIFIER

CIRCUIT USING BJT

Signature of Lab In-charge

ELECTRONIC CIRCUIT ANALYSIS LAB II B TECH II SEMSESTER

VEMU INSTITUTE OF TECHNOLOGY DEPARTMENT OF ECE Page 1

CIRCUIT DIAGRAM:

MODEL WAVEFORMS:

MAGNITUDE PLOT



SIMULATION LAB EXPERIMENTS

Expt No: Date:

1. VOLTAGE SERIES FEEDBACK AMPLIFIER

AIM: To design and simulate the voltage series feedback amplifier using Multisim software and

determine bandwidth.

SOFTWARE REQUIRED: Multisim software 10.0.1 version.

HARDWARE REQUIRED: Personal Computer

PROCEDURE:

1. Design the circuit as per specifications.

2. Simulate the circuit.

3. Observe the response from oscilloscope and obtain the magnitude plot.

4. Extract the output voltage from the magnitude plot and determine voltage gain in dB.

5. Plot the frequency response and determine bandwidth.

BW = f2 – f1.



OBSERVATIONS: VS=20mv

S.NO FREQUENCY(Hz) OUTPUT

VOLTAGE (V0) GAIN

(V0/Vi) GAIN IN dB

Av=20 log10 (V0/Vi)



RESULT:

VIVA QUESTIONS:

1. Why CE Configuration is preferred over other configurations in amplifiers?

2. What is meant by feed back?

3. Define Stability?

4. What are the types of feed backs?

5. What are the advantages of negative feedback in amplifiers?



CIRCUIT DIAGRAM:



Expt No: Date:

2. TWO STAGE RC COUPLED AMPLIFIER

AIM: To design and simulate RC coupled amplifier using Multisim software and determine

bandwidth.



PROCEDURE:



3. Observe the response from oscilloscope and obtain the magnitude plot.

4. Extract the output voltage from the magnitude plot and determine voltage gain in dB.

5. Plot the frequency response and determine bandwidth.

BW = f2 – f1.



OBSERVATIONS: Vi=20mV

MODELWAVE FORMS:

MAGNITUDE PLOT

S.NO FREQUENCY

(Hz)

OUTPUT VOLTAGE (V)

GAIN (V0/Vi)

GAIN IN dB Av=20 log10 (V0/Vi)

V01 V02 AV1 AV2 AV1 AV2



RESULT:

VIVA QUESTIONS:

1. What is the type of capacitors are used in RC coupled amplifier?

2. Why CE configuration is used in amplifiers?

3. If voltage gain of each stage is 10, then calculate the total gain.

4. What is the effect of capacitors Cb, Ce, Cc, on frequency response of two stage RC coupled

amplifier?

5. What type of Coupling is used in above circuit?

6.What are the types of couplings?



CIRCUIT DIAGRAM:

MODELWAVE FORMS:

OUT PUT WAVE FORM :



Expt No: Date:

3(a). RC PHASE SHIFT OSCILLATOR

AIM: To design and simulate RC phase shift oscillator using Multisim software and verify

practical frequency with theoretical frequency.



PROCEDURE:



3. Observe and plot the wave form from oscilloscope.

4. Tabulate the frequencies for different combinations of R and C and compare with the

theoretical value

f = 1/2RC6+4K

Where K = Rc/R, R=R1=R2



MODELWAVE FORMS:

OUTPUT WAVEFORM: θ = 600


OUTPUT WAVEFORM : θ = 180



OBSERVATIONS:

RESULT: .

VIVA QUESTIONS:

1 What is an Oscillator? Classify the various types of Oscillators?

2 What are the constituent parts of an Oscillator?

3 What phase angle introduced by ideal and practical RC section for oscillation?

4 What is the main difference between an Oscillator and an Amplifier?

5 Why three RC networks are necessary for a phase-shift oscillator.



CIRCUIT DIAGRAM:

MODEL WAVE FORM:



Expt No: Date:

3(b). WEIN BRIDGE OSCILLATOR

AIM: To design and simulate Wein Bridge oscillator using Multisim software and verify

practical frequency with theoretical frequency.



PROCEDURE:



3. Observe and plot the wave form from oscilloscope.

4. Tabulate the frequencies for different combinations of R and C and compare with the

theoretical value

f = 1/2√R1R2 C1C2



OBSERVATIONS:

S.NO

C1 (µF)

C2

(µF)

CEq

(µF)

THEORETICAL f(HZ)

PRACTICAL Tp(msec)

PRACTICAL f(HZ)

OUTPUT VOLTAGE

(V)

CALCULATIONS:

Theoritical :

fT = 1/ 2√RC=

Practical :

fP = 1/Tp=

OUTPUT VOLTAGE ( V0 ) =



RESULT:

VIVA QUESTIONS:

1. What is the range of frequency for which Wein bridge oscillator is meant for?

2. What is meant by Balancing of bridge?

3. Identify four arms of the Wein Bridge in the circuit?

4. What are the limitations of Wein bridge oscillator?

5. Mention the applications of oscillators.



CIRCUIT DIAGRAM:

MODELWAVE FORMS:



Expt No: Date:

4. CLASS – A AMPLIFIER

AIM: To design and simulate Class - A amplifier using Multisim software and compare practical

efficiency with theoretical value.



PROCEDURE:



3. Observe the response from oscilloscope.

4. Calculate the efficiency and compare it with theoretical value.

5. Plot the graph for simulated output.



CALCULATIONS:

%Efficiency ( η ) = 𝑃𝑂 (𝐴𝐶)

𝑃𝐼 (𝐷𝐶)𝑋100 Where Po= output power

Pi = input power

From CRO

Vm =

To find input power( Pi) To find output power (Po)

IC = 2𝑉𝑚

𝜋𝑅𝐿 = Vrms =

𝑉𝑚

√2 =

Pi = VCC*IC = Po = 𝑉𝑟𝑚𝑠

2

𝑅𝐿 =

%Efficiency ( η ) = 𝑷𝒐

𝐏𝐢X100 =



RESULT:

VIVA QUESTIONS:

1. Define conversion efficiency of a power amplifier.

2. What is its value for efficiency for Class A, B and C power amplifier?

3. What is the criterion for the classification of power amplifiers?

4. What is the advantage of using the output transformer for a class A amplifier?

5. What is the disadvantage of transformer coupled class A amplifier?



CIRCUIT DIAGRAM:

BLOCK DIAGRAM:

Amplifier

Z1

Z3

Z2



Expt No: Date:

5(a). COLPITT’S OSCILLATOR

AIM: To design and simulate Colpitts oscillator and verify it to the theoretical

value.



PROCEDURE:






CALCULATIONS:



MODEL WAVE FORM:

TABULAR COLUMN:

SL.

NO.

L (mH)

C1 (µF) C2 (µF)

THEORETICAL

f(HZ)

PRACTICAL

Timeperiod

(sec)

PRACTICAL

f(HZ)

AMPLITUDE

(V)



RESULT :

VIVA QUESTIONS:

1. What is feedback and what type of feedback is used in oscillators?

2. What is meant by positive and negative feedback?

3. What is the loop phase shift of oscillator?

4. What is the principle of Oscillator?

5. Mention the types of oscillators.



CIRCUIT DIAGRAM:

BLOCK DIAGRAM

Amplifier

Z1

Z3

Z2



Expt No: Date:

5(b).HARTLEY OSCILLATOR

AIM: To design and simulate Hartley oscillator and verify it to the theoretical

value



PROCEDURE:






CALCULATIONS:



MODEL WAVE FORM:

TABULAR COLUMN:

SL.

NO. C (µF) L1 (mH) L2 (mH)

THEORETICAL

f(HZ)

PRACTICAL

Timeperiod(sec)

PRACTICAL

f(HZ)

AMPLITUDE

(V)



RESULTS:

VIVA QUESTIONS:

1. What are the advantages and disadvantages of negative feedback?

2. What are the conditions for sustained oscillator or what is Backhouse criterion?

3. What are the types of feedback oscillators?

4. What is LC oscillator?

5. How does an oscillator differ from an amplifier?



CIRCUIT DIAGRAM:

MODEL WAVE FORM:



Expt No: Date:

6. DARLINGTON PAIR

AIM: To design and simulate Darlington pair and determine bandwidth.



PROCEDURE:








OBSERVATIONS:

Vi=1.5V


VOLTAGE (V)

GAIN

(V0/Vs)

GAIN IN dB

Av=20 log10 (V0/Vs)



RESULT:

VIVA QUESTIONS:

1. What is a Darlington pair?

2. What is the advantage of Darlington configuration?

3. Give few applications of Darlington amplifier

4. Why does amplifier gain reduce at high frequencies?

5. State the types of distortions in amplifier.



CIRCUIT DIAGRAM:

MODEL GRAPH:

Vcc=10V



Expt No: Date:

7. SINGLE TUNED VOLTAGE AMPLIFIER

AIM: To design and simulate single tuned voltage amplifier using MULTISIM and verify practical

frequency with theoretical frequency.



PROCEDURE:




4. Calculate the gain and bandwidth.




OBSERVATIONS:

VS=50mV

CALCULATIONS:


VOLTAGE (V)

GAIN (V0/Vi)




RESULT:

VIVA QUESTIONS:

1. Explain the different regions in frequency response.

2. What is meant by tuned amplifier?

3. Define the term bandwidth of an amplifier?

4. Why we need to use tuned amplifiers?

5. Mention applications of Tuned amplifiers.



CIRCUIT DIAGRAM:

INPUT AND OUT WAVEFORM:



Expt No: Date:

8.CURRENT SHUNT FEEDBACK AMPLIFIER

AIM: To design and simulate current shunt feedback amplifier and determine gain&

bandwidth.



PROCEDURE:









MODELWAVE FORMS:

FREQUENCY RESPONSE:


VOLTAGE (V0)

GAIN

(V0/Vi)

GAIN IN dB

Av=20 log10 (V0/Vi)



RESULT:

VIVA QUESTIONS:

1. What is the parameter which does not change with feedback? 2. Give the effect of negative feedback on amplifier characteristics 3. What happens to output resistance due to current sampling? 4. What is the effect of input resistance due to shunt mixing? 5. Explain the terms feedback factor and open loop gain? 6. Explain the stability of feedback amplifier?



CIRCUIT DIAGRAM:

INPUT WAVE FORM:

OUTPUT WAVE FORM:



Expt No: Date:

9.CLASS-B PUSHPULL AMPLIFIER

AIM: To design and simulate Class B pushpull Amplifier and to determine its efficiency



PROCEDURE:









MODELWAVE FORMS:

FREQUENCY RESPONSE:


VOLTAGE (V0)

GAIN

(V0/Vi)

GAIN IN dB

Av=20 log10 (V0/Vi)



RESULT:

VIVA QUESTIONS:

1.What is meant by conversion efficiency?

2. Which type of power amplifier has the maximum conversion efficiency? Why?

3. To which class does the push-pull amplifier belongs and what are the advantages of it?

4. What is meant by crossover distortion? In which power amplifier it is maximum?

5. Which harmonics are eliminated in the class –B push-pull amplifier



CIRCUIT DIAGRAM:

INPUT AND OUTPUT WAVEFORMS:



Expt No: Date:

10.CLASS-B COMPLEMENTARY SYMMETRY AMPLIFIER

AIM: To design and simulate a Class B complementary -Symmetry Amplifier and to determine

its efficiency.



PROCEDURE:









MODELWAVE FORMS:

FREQUENCY RESPONSE:


VOLTAGE (V0)

GAIN

(V0/Vi)

GAIN IN dB

Av=20 log10 (V0/Vi)



RESULT:

VIVA QUESTIONS:

1. Define power amplifier.

2. Define complementary symmetry amplifier.

3. Is this amplifier working in class A or B.? 4. How can you reduce cross over distortion? 5. What is the theoretical efficiency of the complementary stage amplifier



CIRCUIT DIAGRAM:

INPUT WAVE FORM:

OUTPUT WAVE FORM:



Expt No: Date:

1. VOLTAGE SERIES FEEDBACK AMPLIFIER

AIM: To find the gain and bandwidth of the Voltage Series feedback amplifier with & without

feedback

APPARATUS:

S.NO APPARATUS RANGE QUANTITY

1 Transistor(BC107) - 1

2 Resistors 100KΩ 10KΩ 1KΩ 4.7KΩ

1 2 2 1

3 Capacitors 10µF 3

4 RPS 0-30V 1

5 Function Generator 0-3MHz 1

6 CRO 30MHz 1

7 Bread board - 1

8 Connecting wires - REQUIRED

OPERATION:

The fraction of output voltage is applied in series with input voltage through feedback circuit. Feedback circuit shunt the output but in series with input. So the output impedance is decreased while input impedance is increased. The input & output impedance of an ideal voltage series feedback amplifier is infinite & zero respectively. The resistor RE is used to provide necessary biasing for the amplifier with voltage series feedback gain of the amplifier decreases

PROCEDURE:

1. Connect the circuit as shown in circuit diagram.



2. Apply the source voltage of 20mV peak-to-peak at 1 KHz frequency using Function Generator and note down input voltage.

3. Measure the Output Voltage Vo (p-p) for various frequency values. 4. The voltage gain can be calculated by using the expression: Av= (V0/Vi) 5. All the readings are tabulated and voltage gain in dB is calculated by Using The expression

Av=20 log10 (V0/Vi) 6. A graph is drawn by taking frequency on x-axis and gain in dB on y-axis

On Semi-log graph. The Band Width of the amplifier is calculated from the graph Using the expression, Bandwidth, BW=f2-f1

The Gain bandwidth product of the amplifier is calculated using the Expression

Gain Bandwidth product=3-dBmidband gain X Bandwidth



VOLTAGE (V0)

GAIN

(V0/Vi)

GAIN IN dB

Av=20 log10 (V0/Vi)



MODELWAVE FORMS:

FREQUENCY RESPONSE:

RESULT:

CONCLUSION:

In voltage series feedback amplifiers gain is reduced but stability of gain is more, band width is

increased when compared to amplifier without feedback.

Output resistance will decrease due to shunt connection at output and input resistance

will increase due to series connection at input

VIVA QUESTIONS:

1. What do you understand by feedback in amplifiers?

2. Explain the terms feedback factor and open loop gain?

3. What are the types of feedback?

4. Explain the basic concept of feedback?

5. Compare the negative feedback and positive feedback?

6. Explain the stability of feedback amplifier



CIRCUIT DIAGRAM:

MODELGRAPH:-

INPUT WAVE FORM:

FIRST STAGE OUTPUT:

SECOND STAGE OUTPUT:



Expt No: Date:

2. TWO STAGE RC COUPLED AMPLIFIER

AIM: To design and verify two stages RC coupled amplifier and determine bandwidth.

APPARATUS:



2 Resistors 100KΩ 10KΩ 1KΩ 4.7KΩ 2.2 KΩ

2 2 3 2 1

3 Capacitors 10µF 47µF

3 1

4 RPS 0-30V 1


6 CRO 30MHz 1

7 Bread board - 1


OPERATION: When input AC. signal is applied to the base of the transistor of the 1st stage of RC coupled amplifier, from the function generator, it is then amplified across the output of the 1st stage. This amplified voltage is applied to the base of next stage of the amplifier, through the coupling capacitor Cout where it is further amplified and reappears across the output of the second stage. Thus the successive stages amplify the signal and the overall gain is raised to the desired level. Much higher gain can be obtained by connecting a number of amplifier stages in succession.

Resistance-capacitance (RC) coupling in amplifiers are most widely used to connect the output of first stage to the input (base) of the second stage and so on. This type of coupling is most popular because it is cheap and provides a constant amplification over a wide range of frequencies.

PROCEDURE:

1. Connect the circuit as shown in circuit diagram. 2. Apply the source voltage of 20mV peak-to-peak at 1 KHz frequency using Function

Generator and note down input voltage. 3. Measure the Output Voltage Vo (p-p) for various frequency values. 4. The voltage gain can be calculated by using the expression: Av= (V0/Vi) 5. All the readings are tabulated and voltage gain in dB is calculated by Using The expression







OBSERVATIONS: VS=20 mv

S.NO FREQUENCY

(Hz)

OUTPUT VOLTAGE (V0)

GAIN (V0/Vi)


V01 V02 AV1 AV2 AV1 AV2



FREQUENCY RESPONSE:

RESULT:

CONCLUSION:

The overall gain doubles in two stages RC coupled amplifier than single stage amplifier.

The frequency response of RC amplifier provides constant gain over a wide frequency range

VIVA QUESTIONS:

1. What are the advantages and disadvantages of multi-stage amplifiers?

2. Why gain falls at HF and LF?

3. Why the gain remains constant at MF?

4. Explain the function of emitter bypass capacitor, CE?

5. How the band width will effect as more number of stages are cascaded?

6. Give the formula for effective lower cut-off frequency, when N-number of stages is cascaded?



CIRCUIT DIAGRAM:

MODEL GRAPH:

Vcc=10V



Expt No: Date:

3. SINGLE TUNED VOLTAGE AMPLIFIER

AIM: To design single tuned voltage amplifier and verify practical frequency with theoretical

frequency.

APPARATUS:


1 TRANSISTOR(SL100) - 2

2 Resistors 56KΩ 33KΩ 580Ω 100KΩ

1 1 1 1

3 Capacitors 1µF 0.1µF

2 1

4 DIB - 1

5 Function generator 0-30MHz 1

6 RPS 0-30V 1

7 CRO 30MHz 1

8 Bread board - 1


OPERATION: The circuit operation of single tuned amplifiers begins with the application of the high-frequency signal that is to be amplified at the base-emitter terminal of the transistor, shown in the figure above. By varying the capacitor employed in the tuned circuit, the resonant frequency of the circuit can be made equivalent to the frequency of the applied input signal. Here, the high impedance is offered to the signal frequency by the tuned circuit. Thus, a large output is achieved. For an input signal with multiple frequencies, only the frequency that corresponds to resonant frequency will get amplified. While all other frequencies are rejected the LC circuit. Hence, only the desired frequency signal gets selected and thus amplified by the circuit.

PROCEDURE:

1. Connections are made as per the circuit diagram.

2. A signal of 1 KHz frequency and 50mV peak-to-peak of sine wave is applied at the

Input of amplifier.

3. By keeping the input voltage constant, vary the frequency from 1KHz to 2KHz in regular steps

and note down the corresponding output voltage.

https://electronicscoach.com/single-tuned-amplifiers.html#figure



4. Calculate practically the frequency of oscillations by using the expression.

f =1/Td

Where Td= Time period of the waveform

and compare it with the theoretical frequency f = 1/2C L

5. Voltage gain in dB is calculated by using the expression,

Av=20log10(V0/Vi)

6. Plot graph for gain (Av) in dB vs frequency in Hz on a semi log graph.

7. The Bandwidth of the amplifier is calculated from the graph using the

Expression,

Bandwidth BW=f2-f1 Where f1 is lower 3 dB frequency

f2 is upper 3 dB frequency

OBSERVATIONS:

VS=50mV


VOLTAGE (V)

GAIN (V0/Vi)




CALCULATIONS:

Theoretical frequency f = 1/2C L

Practical frequency f = 1/Td

RESULT:

CONCLUSION:

Resonant frequency is calculated by using the single tuned circuit with L and C values at

maximum voltage.

VIVA QUESTIONS:

1. Define tuned amplifier? What are the various types of tuned amplifier?

2. What are small signal tuned amplifiers?

3. What are the types of single tuned amplifier?

4. Discuss the effect of cascading tuned amplifiers on bandwidth?

5. Derive the equation for the 3dB bandwidth of capacitance coupled single tuned amplifier?

6. What are doubled tuned amplifiers?



CIRCUIT DIAGRAM:

BLOCK DIAGRAM:

Amplifier

Z1

Z3

Z2



Expt No: Date:

4(a). COLPITT’S OSCILLATOR

AIM: To determine the frequency of the Colpitts oscillator and verify it to the theoretical

Value.

APPARATUS:



2 Resistors 47KΩ 1KΩ 150Ω

2 1 1

3 Capacitors 10µF 100µF

2 1

4 DIB - 1

5 DCB - 2

7 RPS 0-30V 1

8 CRO 30MHz 1

9 Bread board - 1


OPERATION: When power supply is switched ON, capacitors C1 and C2 starts charging. When they are fully charged they start discharging through the inductor L1. When the capacitors are fully discharged, the electrostatic energy stored in the capacitors gets transferred to the inductor as magnetic flux. The inductor starts discharging and capacitors gets charged again. This transfer of energy back and forth between capacitors and inductor is the basis of oscillation. Voltage across C2 is phase opposite to that of the voltage across the C1 and it is the voltage across C2 that is fed back to the transistor. The feedback signal at the base of transistor appears in the amplified form across the collector and emitter of the transistor. The energy lost in the tank circuit is compensated by the transistor and the oscillations are sustained. The tank circuit produces 180° phase shift and the transistor itself produces another 180° phase shift. That means the input and output are in phase and it is a necessary condition of positive feedback for maintaining sustained oscillations. The frequency of oscillations of the Colpitts oscillator can be determined using the equation below.



The resonant frequency is given by

ƒr=1/(2П√(L1*C))

Where ƒr is the resonant frequency,C is the equivalent capacitance of series combination of C1

and C2 of the tank circuit

It is given as C=(C1*C2)/((C1+C2))

L1 represents the self inductance of the coil.

PROCEDURE: 1. Connect the circuit diagram as shown in the figure

2. Set VCC = 12V

3. Keep the inductance of the decade inductance box to 3mH, and measure the generated output signal amplitude and frequency from CRO.

4. Vary the Capacitance in steps and note down frequency and amplitude at each.

5. Plot the graph from CRO and verify the practical frequency with theoretical frequency.

CALCULATIONS:

Theoretical frequency f0 = 1/2Ceq L

Where Ceq = 1/C1 + 1/C2 = C1C2/C1 + C2

MODEL WAVE FORM:



TABULAR COLUMN:

SL.

NO.

L (mH)

C1 (µF) C2 (µF)

THEORETICAL

f(HZ)

PRACTICAL

Timeperiod

(sec)

PRACTICAL

f(HZ)

AMPLITUDE

(V)

RESULT :

CONCLUSION:

Oscillations are produced at a desired frequency with the values of L,C1 and C2.

Practical frequency of oscillations is approximately same as theoretical frequency.

Colpitts oscillator produces oscillations at high frequency.

VIVA QUESTIONS:

1. What is an oscillator? What are the types of oscillator?

2. Explain the main difference between an amplifier and an oscillator?

3. What are the constituent parts of an oscillator?

4. State and briefly explain Barkhausen criterion for oscillation?

5. What is the frequency of oscillation for Colpitt’s oscillator



CIRCUIT DIAGRAM:

BLOCK DIAGRAM

Amplifier

Z1

Z3

Z2



Expt No: Date:

4(b).HARTLEY OSCILLATOR

AIM: To determine the frequency of the Hartley oscillator and verify it to the theoretical

value

APPARATUS:

S.NO EQUIPMEN/COMPONENTS RANGE QUANTITY


2 Resistors 22KΩ

1KΩ

470Ω

6.8KΩ

1

1

1

1

3 Capacitors 100µF 2.2µF

2 1

4 DIB - 1

5 DCB - 1

6 RPS 0-30V 1

7 CRO 30MHz 1

8 Bread Board - 1

9 Connecting Wires - REQUIRED

OPERATION: When the power supply is switched ON the transistor starts conducting and the collector current increases. As a result the capacitor C1 starts charging and when the capacitor C1 is fully charged it starts discharging through coil L1. This charging and discharging creates a series of damped oscillations in the tank circuit and it is the key. The oscillations produced in the tank circuit is coupled (fed back) to the base of Q1 and it appears in the amplified form across the collector and emitter of the transistor. The output voltage of the transistor (voltage across collector and emitter) will be in phase with the voltage across inductor L1. Since the junction of two inductors is grounded, the voltage across L2 will be 180° out of phase to that of the voltage across L1. The voltage across L2 is actually fed back to the base of Q1. From this we can see that, the feed back voltage is 180° out of phase with the transistor and also the transistor itself will create another 180° phase difference. So the total phase difference between input and output is 360° and it is very important condition for creating sustained oscillations. The frequency “F” of a Hartley oscillator can be expressed using the equation;

http://www.circuitstoday.com/wp-content/uploads/2009/10/hartley-oscillator-frequency.png



C is the capacitance of the capacitor C1 in the tank circuit. L = L1+L2, the effective series inductance of the inductors L1 and L2 in the tank circuit. Here the coils L1 and L2 are assumed to be winded on different cores. If they are winded on a single core then L=L1+L2+2M where M is the mutual inductance between the two coils.

PROCEDURE:

1. Connect the circuit diagram as shown in the figure

2. Set VCC = 12V

3. Keep the capacitance of the decade capacitance box to 0.1µF, and measure the

generated output signal amplitude and frequency from CRO.

4. Vary the Inductance in steps and note down frequency and amplitude at each.


CALCULATIONS:

Theoretical frequency fo = 1/2CLeq

Where L = L1+L2

C = Capacitance of decade capacitance box at particular frequency

MODEL WAVE FORM:



TABULAR COLUMN:

SL.

NO. C (µF) L1 (mH) L2 (mH)

THEORETICAL

f(HZ)

PRACTICAL

Timeperiod(sec)

PRACTICAL

f(HZ)

AMPLITUDE

(V)

RESULTS:

CONCLUSION:

Oscillations are produced at a desired frequency with the values of C,L1 and L2.


Hartley oscillator produce oscillations at high frequency

VIVA QUESTIONS:

1. What are the advantages and disadvantages of negative feedback?

2. What are the conditions for sustained oscillator or what is Backhouse criterion?

3. What are the types of feedback oscillators?

4. What is LC oscillator?

5. How does an oscillator differ from an amplifier?



CIRCUIT DIAGRAM:

MODEL WAVE FORM:



Expt No: Date:

5. DARLINGTON PAIR

AIM: To obtain the frequency response of Darlington pair and determine bandwidth.

APPARATUS:


1 Transistor(SL100) - 2

2 Resistors 100KΩ

200KΩ

1

1


4 RPS 0-30V 1

5 CRO 30MHz 1

6 Bread Board - 1


OPERATION:

A Darlington transistor pair comprises of a couple of bipolar transistors that are coupled in

order to deliver a very high-current gain from a low-base current.

It is cascading of common collector-common collector. In this circuit, the emitter of the input

transistor is connected to the base terminal of the output transistor.

Therefore, the current that is amplified by the first transistor is again amplified by the second

transistor.

The current gain of single stage cc amplifier is high,so by using darlington pair we can get high

current gain.

PROCEDURE:

1. Design the circuit for given specifications and connect the circuit.

2. Apply input signal to the circuit of 1.5Vp-p, 1 KHz sine wave from the function generator with DC offset ON.

3. Tabulate amplitude of output signal with change in frequency with steps from 10Hz to 1MHz and determine gain using Av = V0/Vs.

4. Calculate voltage gain in dB using Av = 20 log10(V0/Vs).

5. Plot the frequency response on semi-log graph using the values of amplitude in dB vs frequency in Hz.

6. Calculate the bandwidth using BW = f2 – f1.

PRECUATIONS:

https://www.elprocus.com/what-are-the-types-field-effect-transistor/



1. DC offset should be ON, to avoid clipping.

OBSERVATIONS:

Vi=1.5V


VOLTAGE (V)

GAIN

(V0/Vs)

GAIN IN dB

Av=20 log10 (V0/Vs)



RESULT:

CONCLUSION: This configuration gives high current gain than each transistor taken separately.

VIVA QUESTIONS:

1. What is a Darlington pair?

2. What is the advantage of Darlington configuration?

3. Give few applications of Darlington amplifier

4. Why does amplifier gain reduce at high frequencies?

5. State the types of distortions in amplifier.



CIRCUIT DIAGRAM:

MODELWAVE FORMS:

OUT PUT WAVE FORM :



Expt No: Date:

6(a). RC PHASE SHIFT OSCILLATOR

AIM: To design a RC phase shift oscillator and verify practical frequency with theoretical

Frequency.

APPARATUS:



2 Resistors

3 Capacitors

4 DIB - 1

5 DCB - 1

6 RPS 0-30V 1

7 CRO 30MHz 1

8 Bread Board - 1


\OPERATION: When the circuit is switched on, current through R3 starts increasing because of biasing. This charging current induces voltage across R2 through C3. The voltage across R2 leads the voltage across R3 by 600.since three R-C sections are provided, therefore, the phase shift circuit produces a total phase shift of 60x3=1800.

A further phase shift of 1800is produced due to the transistor properties.So a total shift of 360 degrees is produced. Therefore a fraction of the output fed to the input is in phase with it. The frequency of the transistor RC phase shift oscillator oscillator can be expressed by the equation:

Where F is the frequency, R is the resistance, C is the capacitance and N is the number of RC phase shift stages. The RC phase shift oscillator can be made variable by making the resistors or capacitors variable. The common approach is to leave the resistors untouched the three capacitors are replaced by a triple gang variable capacitor.

http://www.circuitstoday.com/wp-content/uploads/2009/10/rc-phase-shift-oscillator-frequency-equation.png




2. Set VCC = 12V





MODELWAVE FORMS:





OUTPUT WAVEFORM : θ = 180

CALCULATIONS:

RESULT:



CONCLUSION:

Oscillations at low frequency are produced by using RC phase shift oscillator.


The angle at single RC network is measured a 600, two RC network as 1200 ,three RC network as

1800 .

VIVA QUESTIONS:

1. What is the necessity of cascading?

2. What is 3dB bandwidth?

3. Why RC coupling is preferred in audio range?

4. Which type of coupling is preferred and why?

5. Explain various types of Capacitors?

6. What is loading effect?



CIRCUIT DIAGRAM:

MODEL WAVE FORM:



Expt No: Date:

6(b). WEIN BRIDGE OSCILLATOR

AIM: To design a Wein Bridge oscillator and verify practical frequency with theoretical

frequency.

APPARATUS:

S.NO EQUIPMENT/COMPONENTS RANGE QUANTITY


2 Resistors

3 Capacitors

4 DIB - 1

5 DCB - 1

6 RPS 0-30V 1

7 CRO 30MHz 1

8 Bread Board - 1


OPERATION:

The circuit is in the oscillation mode and the base current of the first transistor is changed randomly because it is due to the difference in voltage of DC supply.

The base current is applied to the collector terminal of the first transistor and the phase shift is about the 180°. The output of the first transistor is given to the base terminal of the second transistor Q2 with the help of the capacitor C4. Further, this process is amplified and from the second transistor of collector terminal the phase reversed signal is collected. The output signal is connected to the phase with the help of the first transistor to the base terminal.



The input point of the bridge circuit is from the point A to point C the feedback of this circuit is the output signal at the second transistor. The feedback signal is given to the resistor R4 which gives the negative feedback. In this same way the feedback signal is given to the base bias resistor R4 and it produces the positive feedback signal. By using the two capacitors C1 and C2 in this oscillator, it can behave continuous frequency variation. These capacitors are the air gang capacitors and we can also change the values of the frequency range of the oscillator.


2. Set VCC = 12V





OBSERVATIONS:

S.NO

C1 (µF)

C2

(µF)

CEq

(µF)

THEORETICAL f(HZ)

PRACTICAL Tp(msec)

PRACTICAL f(HZ)

OUTPUT VOLTAGE

(V)

CALCULATIONS:

Theoritical :

fT = 1/ 2√RC=



Practical :

fP = 1/Tp=

OUTPUT VOLTAGE ( V0 ) =

RESULT:

CONCLUSION:

The desired frequency of oscillations is produced by varying two capacitors C1 and C2

simutaneously.

Phase shift is produced by using two transistors. Each transistor produces a phase shift of 1800

And hence a phase shift of 3600 is obtained.

VIVA QUESTIONS:

1. Give the formula for frequency of oscillations in Wein Bridge Oscillator circuit?

2. What is the condition for Wien Bridge oscillator to generate oscillations?

3. What is the total phase shift provided by the Wein Bridge oscillator?

4. What is the function of lead-lag network in Wein Bridge oscillator?

5. Which type of feedback is used in Wein Bridge oscillator



CIRCUIT DIAGRAM:

MODELWAVE FORMS:



Expt No: Date:

7. CLASS – A AMPLIFIER

AIM: To design a Class - A amplifier using and compare practical efficiency with theoretical

value.

APPARATUS:



2 Resistors As per the

circuit

3 Capacitors As per the circuit

4 DIB - 1

5 DCB - 1

6 RPS 0-30V 1

7 CRO 30MHz 1

8 Bread Board - 1


OPERATION: The above-shown circuit is a directly coupled Class A amplifier. An amplifier where the load is coupled to the output of the transistor using a transformer is called a direct coupled amplifier. Using transformer coupling technique, the efficiency of an amplifier can be enhanced to a great extent. The coupling transformer provides good impedance matching between the load and output, and it is the main reason behind the improved efficiency.

Generally, the current flows through the collector resistive load, this will cause the wastage of the DC power in it. As a result, this DC power dissipated in the load in a form of heat, and it does not contribute any output AC power.

Hence it is not advisable to pass the current through the output device (ex: loudspeaker) directly.For this reason, a special arrangement done by using a suitable transformer for coupling the load to the amplifier as given in the above circuit.

The circuit has the potential divider resistors R1 & R2, biasing and emitter bypass resistor Re, used for circuit stabilization. The emitter bypass capacitor CE and emitter resistor Re are connected parallel to prevent AC voltage.The input capacitor Cin (Coupling Capacitor) used to couples AC input signal voltage to the base of the transistor and it blocks the DC from the previous stage.

https://www.elprocus.com/darlington-transistor-pair-circuit-with-working/

https://www.elprocus.com/capacitors-types-applications/



PROCEDURE: 1. Connect the circuit as shown in circuit diagram. 2. Apply the sourse voltage of 20mV peak-to-peak at 1 KHz frequency using Function

Generator and note down input voltage. 3. Measure the Output Voltage Vo (p-p) for various frequency values. 4. The voltage gain can be calculated by using the expression: Av= (V0/Vi) 5. All the readings are tabulated and voltage gain in dB is calculated by Using The expression





CALCULATIONS:

%Efficiency ( η ) = 𝑃𝑂 (𝐴𝐶)

𝑃𝐼 (𝐷𝐶)𝑋100 Where Po= output power

Pi = input power

RESULT:

CONCLUSION:

The efficiency of class A power amplifier is approximately equal to 25%.

VIVA QUESTIONS:

1. Define class A power amplifier?

2. Give the reason why class A power amplifier is called as directly coupled power amplifier?

3. What is the efficiency of class A power amplifier?

4. In a power transistor, when the maximum power dissipation takes place?

5. List out the different types of distortions?



CIRCUIT DIAGRAM:

INPUT &OUTPUT WAVE FORMS:



Expt No: Date:

8.CURRENT SHUNT FEEDBACK AMPLIFIER

AIM: 1.To study the current shunt feedback amplifier

2. To measure the voltage gain of the amplifier at 1KHz.

3. To obtain the frequency response characteristic and the bandwidth

.

APPARATUS:



2 Resistors

3 Capacitors

4 RPS 0-30V 1


6 CRO 30MHz 1

7 Bread board - 1


OPERATION:

For the shunt-series connection, the configuration is defined as the output current, Iout to the input current, Iin. In the shunt-series feedback configuration the signal fed back is in parallel with the input signal and as such its the currents, not the voltages that add.

This parallel shunt feedback connection will not normally affect the voltage gain of the system, since for a voltage output a voltage input is required. Also, the series connection at the output increases output resistance, Rout while the shunt connection at the input decreases the input resistance, Rin.

Then the “shunt-series feedback configuration” works as a true current amplifier as the input signal is a current and the output signal is a current, so the transfer gain is given as: Ai = Iout ÷ Iin. Note that this quantity is dimensionless as its units are amperes/amperes.



PROCEDURE:

1.Connect the circuit as shown in circuit diagram. 2.Apply the sourse voltage of 20mV peak-to-peak at 1 KHz frequency using Function Generator and note down input voltage.

3.Measure the Output Voltage Vo (p-p) for various frequency values. 4.The voltage gain can be calculated by using the expression: Av= (V0/Vi) 5.All the readings are tabulated and voltage gain in dB is calculated by Using The expression Av=20 log10 (V0/Vi) 6 .A graph is drawn by taking frequency on x-axis and gain in dB on y-axis

On Semi-log graph. 7. The Band Width of the amplifier is calculated from the graph Using the expression, Bandwidth, BW=f2-f1

8.The Gain bandwidth product of the amplifier is calculated using the Expression




VOLTAGE (V0)

GAIN

(V0/Vi)

GAIN IN dB

Av=20 log10 (V0/Vi)



MODELWAVE FORMS:

FREQUENCY RESPONSE:

RESULT:

CONCLUSION:

In current shunt feedback amplifiers gain is reduced but stability of gain is more, band width is

increased when compared to amplifier without feedback.

VIVA QUESTIONS:

1. What is the parameter which does not change with feedback? 2. Give the effect of negative feedback on amplifier characteristics 3. What happens to output resistance due to current sampling? 4. What is the effect of input resistance due to shunt mixing? 5. Explain the terms feedback factor and open loop gain? 6. Explain the stability of feedback amplifier?



CIRCUIT DIAGRAM:

MODEL WAVE FORM:



Expt No: Date:

9.CLASS-B PUSHPULL AMPLIFIER

AIM: : To design a class-B push-pull power amplifier in order to achieve maximum output AC

power and efficiency.

APPARATUS:



2 Resistors As shown in circuit

3 Capacitors As shown in circuit

4 RPS 0-30V 1


6 CRO 30MHz 1

7 Bread board - 1


OPERATION:

The circuit arrangement of the Class B push pull amplifier is similar to the Class A push pull amplifier except for the absence of the biasing resistors. T1 is the input coupling capacitor and the input signal is applied to its primary. Q1 and Q2 are two identical transistors and their emitter terminals are connected together.

Center tap of the input coupling transformer and the negative end of the voltage source is connected to the junction point of the emitter terminals. Positive end of the voltage source is connected to the center tap of the output coupling transformer. Collector terminals of each transistor are connected to the respective ends of the primary of the output coupling transformer T2. Load RL is connected across the secondary of T2.

The input signal is converted into two similar but phase opposite signals by the input transformer T1. One out of these two signals is applied to the base of the upper transistor while the other one is applied to the base of the other transistor. You can understand this from the circuit diagram

. When transistor Q1 is driven to the positive side using the positive half of its input signal, the reverse happens in the transistor Q2. That means when the collector current of Q1 is going in the increasing direction, the collector current of Q2 goes in the decreasing direction. Anyway the current flow through the respective halves of the primary of the T2 will be in same direction. Have a look at the figure for better understanding. This current flow through the T2



primary results in a wave form induced across its secondary. The wave form induced across the secondary is similar to the original input signal but amplified in terms of magnitude.

PROCEDURE:

1.Connect the circuit diagram as shown in the figure.

2. Determine the maximum signal handling capacity of the push pull amplifier.

3. Apply sinusoidal signal of 4mV peak to peak voltage at a frequency of 1 kHz.

4. Connect Power meter at the O/P terminals.

5. By changing the load at the O/P terminals measure the power in the Power meter.

6. Tabulate the readings.

7. plot the graph between Power vs load


S.NO RL Output Power Power in

db Po (mW) (10 log P0) Power in db (10 log P0)



RESULT:

CONCLUSION:

The efficiency of class B pushpull is higher than class A.

Frequency response is poor.

VIVA QUESTIONS:

1.What is meant by conversion efficiency?

2. Which type of power amplifier has the maximum conversion efficiency? Why?

3. To which class does the push-pull amplifier belongs and what are the advantages of it?

4. What is meant by crossover distortion? In which power amplifier it is maximum?

5. Which harmonics are eliminated in the class –B push-pull amplifier



CIRCUIT DIAGRAM:

INPUT WAVE & OUTPUT WAVE FORMS:



Expt No: Date:

10.CLASS-B COMPLEMENTARY SYMMETRY AMPLIFIER

AIM: To design a complementary-symmetry class-B push-pull power amplifier in order to

achieve maximum output AC power and efficiency.

APPARATUS:



2 Resistors 4.7k ,15k

3 Capacitors 100µ F

4 RPS 0-30V 1


6 CRO 30MHz 1

7 Bread board - 1


Operation: The above circuit employs a NPN transistor and a PNP transistor connected in push pull configuration. When the input signal is applied, during the positive half cycle of the input signal, the NPN transistor conducts and the PNP transistor cuts off. During the negative half cycle, the NPN transistor cuts off and the PNP transistor conducts.

In this way, the NPN transistor amplifies during positive half cycle of the input, while PNP transistor amplifies during negative half cycle of the input. As the transistors are both complement to each other, yet act symmetrically while being connected in push pull configuration of class B, this circuit is termed as Complementary symmetry push pull class B

amplifier.

PROCEDURE:

1.Connect the circuit as shown in circuit diagram. 2.Apply the sourse voltage of 20mV peak-to-peak at 1 KHz frequency using Function Generator and note down input voltage.

3.Measure the Output Voltage Vo (p-p) for various frequency values. 4.The voltage gain can be calculated by using the expression: Av= (V0/Vi) 5.All the readings are tabulated and voltage gain in dB is calculated by Using The expression Av=20 log10 (V0/Vi) 6 .A graph is drawn by taking frequency on x-axis and gain in dB on y-axis

On Semi-log graph. 7. The Band Width of the amplifier is calculated from the graph Using the expression, Bandwidth, BW=f2-f1



8.The Gain bandwidth product of the amplifier is calculated using the Expression




VOLTAGE (V0)

GAIN

(V0/Vi)

GAIN IN dB

Av=20 log10 (V0/Vi)



MODELWAVE FORMS:

FREQUENCY RESPONSE:

RESULT:

CONCLUSION:

Frequency response is better than class B.

Crossover distortion occurs.

VIVA QUESTIONS:

1. Define power amplifier.

2. Define complementary symmetry amplifier.

3. Is this amplifier working in class A or B.? 4. How can you reduce cross over distortion? 5. What is the theoretical efficiency of the complementary stage amplifier



ADDITIONAL EXPERIMENTS





Expt No: Date:

SOURCE FOLLOWER WITH BOOTSTRAPPED CIRCUIT

AIM: To construct a source follower with bootstrapped gate resistance amplifier and plot its

frequency response characteristics.

PROCEDURE:


2. The waveforms at the input and output are observed for cascode operations by varying the

input frequency.

3. The biasing resistances needed to locate the Q-point are determined.

4. Set the input voltage as 1V and by varying the frequency, note the output voltage.

5. Calculate gain=20 log (Vo / Vin.)

6. A graph is plotted between frequency and gain.



OBSERVATIONS:

RESULT:



VIVA QUESTIONS:

1. Explain the basic principle involved in bootstrap sweep generator. 2. Mention the type of feedback employed in bootstrap sweep generator.

3. Mention the characteristics of the amplifier used in bootstrap sweep generator.

4. What is input resistance of the bootstrapped amplifiers? 5. What does bootstrapping mean?

6. Why bootstrapping is done in a buffer amplifier?



Expt No: Date:

FIXED BIAS AMPLIFIER CIRCUIT USING BJT



AIM: To construct a fixed bias amplifier circuit and to plot the frequency response characteristics.

PROCEDURE :


2. The waveforms at the input and output are observed for Class A, Class B and Class C operations by varying the input voltages.

3. The biasing resistances needed to locate the Q-point are determined.

4. Set the input voltage as 1V and by varying the frequency, note the output voltage.

5. Calculate gain=20 log (Vo / Vin)

6. A graph is plotted between frequency and gain. CALCULATIONS: a) To determine the value of bias resistance R2 / (R1+ R2) b) hfe =Δ IC/ΔIB



RESULT:

VIVA QUESTIONS:

1. What is biasing?

2. What are different types of biasing?

3. Which biasing is commonly preferred?

4. Define stability factor?

Documents

STUDENT OBSERVATION MANUAL - vemu.orgvemu.org/uploads/lecture_notes/20_01_2020_1218425987.pdf · viva voce (10m) attendan ce (10m) 1 voltage series feedback amplifier 2 two stage