question-paper pattern ANALOG ELECTRONICS CIRCUITS electronic engineering diploma

question-paper pattern  ANALOG ELECTRONICS CIRCUITS electronic  engineering 

Semester end-exam evaluation (SEE)

(i)     End-exam question-paper pattern


Unit Name

Study Duration (Hrs.)

No. Questions for end-exam


5 Marks


10 Marks


Power Supplies





BJT Biasing and amplifiers





OP-amp and applications





Active filters and instrumentation






Wave-shaping circuits





Sinusoidal oscillators








(45 Marks)


(100 Marks)

(ii) Model question paper
Course Code : 15EC31T Time : 3 Hrs Semester : Third Max. Marks: 100 Instructions : 1. Answer any SIX question from Part A (5x6=30 Marks)
2. Answer any SEVEN full questions from Part B (7x10=70 Marks)

Part A
1. Explain the working of Half-wave rectifier with a relevant circuit and waveforms.
2. Identify the rated output voltages of the following regulator ICs.
a) IC-7805 b) IC-7918 c) IC-7912 d) IC-7815 e) IC-LM317
3. Define biasing and operating point. Match the transistor applications (amplifier, switch-open, switch-close) with different regions on output characteristics of transistor.
4. Explain the working of series-fed class-A amplifier
5. List the ideal and practical characteristics of Op-amp
6. Construct a non-inverting amplifier circuit using Op-amp for a gain of 10
7. Show how to realize BPF using LPF and HPF
8. Construct a shunt clipper circuit to generate a signal having maximum positive amplitude of 2V and negative amplitude of -10V for a sinusoidal input of +10 to - 10V.
9. Explain the role of tank circuit in Hartley oscillator; write expression for its frequency of oscillations.
Part B
1. Show mathematically that the efficiency of bridge rectifier is 81.2% and ripple factor is 0.48.
2. a) Define filter. Explain the working of C filter in regulated power supply
b) State the function of UPS. Compare ONLINE and OFFLINE operation of UPS
3. a) In multistage amplifier, illustrate that the overall gain is equal to the product of gains of individual stages
b) Explain the concept of negative feedback and list its disadvantages?
4. (a) Compare the relevance of ac load-line and dc load-line as applicable to amplifiers
(b) Explain the classification of power amplifiers
5. (a) Define any five Op-amp parameters. (b) Construct Schmitt trigger circuit to convert sine wave to square wave
6. (a) In the circuit shown below, if V1= -1V, V2=V3=2V, Supply voltage is ±15V, VR1=R2=4KΩ, R3=2KΩ, and feedback resistance Rf =6KΩ, calculate closed-loop gain and output voltage (6)

(b) Discuss the effect of slew rate on bandwidth in Op-amp applications (4)
7. Construct a first-order Butterworth LPF and HPF circuit for a gain of 10, cut-off frequency of 160Hz and an input impedance of 10KΩ. Assume relevant data if necessary.
8. Explain the need and working of an instrumentation amplifier
9. Define clamper and clipper. Write the output wave form for the clipper circuit shown below

10. a) Draw Wein-bridge oscillator circuit for the output frequency of 200Hz.
b) Compare RC phase-shift oscillator with Collpits oscillator.

The following are suggested institutional activities, to be carried out at least one during the semester. The course teacher/coordinator is expected to maintain the relevant record (Containing, Activity name, Resource persons and their details, duration, venue, student feedback, etc) pertaining to Institutional activities.

Sl. No.



Organize seminar, workshop or lecture from experts on the modern trends in

analog electronics


Organize hands-on practice on design and simulation of analog circuits


Motivate students to take case study on different analog electronics-based mini projects (small applications such as applications specified in student activity) to

inculcate self and continuous learning

  Model Question Bank
Note: The questions in the question bank are indicative but not exhaustive. Sub-questions on different CLs may be combined to frame 10-marks questions or 10-marks questions given here can be splitted into 5-marks questions if necessary keeping weightage of CLs approximately intact and adhering to SEE end-exam pattern.

Unit-1: Power Supplies Five-mark Questions
1. State the roles of different sub-circuits of DC regulated power supply
2. Discuss the need for rectifier in DC regulated power supply. Sketch the output waveform of half-wave rectifier for sinusoidal input
3. Define regulator and explain the need for voltage regulators in power supplies
4. Define line and load regulation and discuss the need for quantifying them
5. List any five IC voltage regulators and mention their rated-output voltage levels
6. State the function of filter in DC regulated power supply. Compare PI filter with C filter
7. Differentiate between fixed IC voltage regulators and variable IC voltage regulators
8. List the features of IC-LM 317.

1. Explain the operation of half-wave rectifier circuit with waveforms and circuit
2. Explain the need for filters in power supplies
3. Describe the working of C filter with circuit diagram and waveforms.
4. Explain the working of PI filter with circuit diagram and waveforms
5. Illustrate the need of Zener diode in voltage regulators
6. List the features of switching regulator.
7. Compare LM317 with IC78xx and IC79xx
8. List the components associated with DC regulated power supply
9. Compare online and offline UPS
10. Differentiate DC regulated power supply with SMPS
11. Discuss the need for SMPS and UPS

1. For the given input Vi=100 sin (314t), calculate the ripple frequency in half-wave and full-wave rectifiers.
2. Construct the circuit that has highest efficiency in ac to dc conversion
3. Show mathematically the ripple factor of a bridge rectifier is 0.48
4. Explain when IC-7805 and IC-7912 regulators can be used
5. Construct a circuit that minimizes ripples in the output of a rectifier circuit and briefly explain how it does
6. Construct a simple circuit that keeps the output dc voltage almost constant irrespective of variation in the input voltage above certain level.

Ten-mark Questions
1. Define a) Rectification, b) Ripple Factor, c) Ripple frequency, d) Efficiency, and e) Peak Inverse Voltage
2. List the different functional blocks and their role in SMPS
3. Define UPS. With a neat block diagram explain the working principle of on-line and offline UPS
4. (a) State the purpose of rectifier, regulator, filter, SMPS and UPS.
(b) Describe the working of simple voltage regulator employing Zener diode
5. (a) Name the different blocks of DC regulated power supply and state their functions
(b) Define PIV and describe its role in rectifier circuits
6. Describe the functioning of bridge rectifier circuit with wave forms and identify the differences with centre-tapped transformer full-wave rectifier.

1. Classify the rectifier circuits. Explain the operation of centre-tapped full-wave rectifier circuit with waveforms.
2. (a) Summarize similarities and differences of centre-tapped full-wave rectifier and bridge rectifier.
(b) Identify the disadvantages of half-wave rectifier
3. (a) Discuss the need for filters and regulators in DC regulated power supplies
(b) Describe the operation of half-wave rectifier circuit with waveforms
4. (a) Compare the features of IC-LM 317 with IC78XX series.
(b) Explain briefly the working of step-down and step-up configuration of switching regulator

5. (a) Differentiate SMPS and Regulated power supply
(b) Explain the functioning of offline UPS with block diagram

1. (a) Construct a circuit that converts square-wave input to DC output shown in the following figure

(b) Explain why PIV restricts the dynamic range of the output voltage in rectifier output
2. Write the block diagram of DC regulated power supply and sketch the wave forms at the output of each block.
3. (a) Illustrate how UPS keeps power supply uninterrupted
(b) List applications of SMPS and DC regulated power supply
4. (a) List the disadvantages of half-wave and centre-tap transformer rectifier
(b) Calculate the dc output voltage and ripple factor of a full-wave rectifier given input
Vi=100 sin (2*3.1415*50t)

Unit-2: BJT Biasing and amplifiers Five-mark Questions
1. Define amplification, gain, frequency response, bandwidth and input impedance as applicable to amplifiers
2. List the features of RC coupled amplifier
3. Locate the region, on output characteristics plot of BJT, for amplification and switching applications
4. Define biasing of BJT and explain the need for biasing
5. List the differences between Class-A and Class-B power amplifiers

1. Explain the principle of operation of transistor as switch
2. Differentiate between AF and RF amplifiers
3. Differentiate between voltage and power amplifiers
4. Classify the power amplifiers
5. Compare power amplifiers with reference to conduction angle and efficiency
6. Differentiate between small and large-signal amplifiers
7. Explain the principle of operation of transistor as an amplifier
8. Show how individual amplifiers are connected to realise multistage amplifier

1. Sketch the output of an CE mode RC coupled amplifier having voltage gain of 100 for the given input vi=0.01 sin(31415t)
2. Four RC coupled amplifiers having gains 3, 6, 2, and 5 are available. Illustrate (block diagram level) how some of these amplifiers can be connected to realise an amplifier with a gain of 30.
3. Identify the power amplifier having highest efficiency and substantiate the reason for it.
4. Sketch the frequency response curve of an RC couple amplifier with relevant labels
5. List the pros and cons of negative feedback in amplifiers
6. Modify Class-B push-pull amplifier to overcome cross-over distortion

Ten-mark Questions
1. (a) Define operating point and describe the role of DC load line to locate it
(b) List the features of transformer coupled amplifier
2. (a) Describe the working of Class AB amplifier
(b) List the features of RC coupled amplifier
3. (a) Tabulate the efficiencies and conduction angles of power amplifiers
(b) List the features of direct coupled amplifier
4. (a) Describe the concept of ac load line and its role in amplifier design
(b) List various categories of amplifiers and their applications

1. (a) Explain the need for biasing with a brief explanation on voltage-divider bias for BJT amplifier
(b) Differentiate between large signal and small signal amplifiers
2. (a) Explain the concept of feedback and list various feedback methods in amplifiers
3. (a) Explain the working of common emitter RC coupled amplifier
(b) Sketch and label frequency response plot of a typical RC coupled amplifier
4. (a) Explain the working of Class-C amplifier
(b) Relate various power amplifiers with conduction angles and efficiencies
5. (a) Compare the features of Class-B push-pull with Class-AB amplifier
(b) Demonstrate how multistage amplifier can be realised with using individual amplifiers

1. (a) Sketch output waveform of an RC coupled amplifier having a gain of 50, given input signal Vi=0.01 sin(3140t).
(b) Illustrate the use dc load line in amplifier biasing
2. (a) Illustrate how the problems in Class-B push-pull amplifier are solved in complementary symmetry Class B amplifier.
(b) Apply principle of cascading to realise multistage amplifier and determine the expression for gain in terms of individual gains
3. (a) Establish a relation between gains of individual stages and overall gain in a multistage amplifier
(b) List the features of RC coupled amplifier
4. Show that the efficiency of class B amplifier is 78.5% and prepare a table comparing its efficiency with other power amplifiers
5. Show that the total gain is equal to the product of gains of individual stages in a multistage amplifier

Unit-3: OP-AMP and applications Five-mark Questions
1. Describe the block diagram of Op-amp
2. List the ideal characteristics of Op-amp
3. Enumerate applications of Op-amp and state their functions
4. List advantages and disadvantages of open-loop mode of Op-amp
5. List any five Op-amp parameters and define them
6. State the functions of integrator, summer, inverting, voltage follower and Schmitt trigger applications of Op-amp

1. Describe the working principle of basic differential amplifier circuit
2. Explain the open-loop configuration of Op-amp as comparator
3. Explain the concept and relevance of virtual ground in Op-amp applications
4. Construct Op-amp circuit having closed-loop gain of -10
5. Sketch the Op-amp circuit that can convert square-wave into pulses with relevant waveforms
6. Discuss the relevance of CMRR and slew-rate on the performance of Op-amp applications
7. Discuss the effect of saturation on the output related to Op-amp applications with example

1. Sketch an Op-amp circuit that translates sine function into cosine function with the mathematical expression for its output
2. Suggest how voltages can be added and amplified together with the help of Op-amp
3. Sketch the Op-amp voltage follower circuit and mathematically justify its gain is 1
4. Construct an Op-amp circuit that converts square-wave into triangular waveform
5. Construct Op-amp circuit to add two voltages and amplify the sum by 5 times
6. Show mathematically that the gain of an inverting amplifier shown below is -Rf/Rin

Ten-mark Questions
1. Define the following terms with reference to Op-amp:
a) Input offset voltage, b) Input offset current, c) Power Supply Rejection Ratio
d) CMRR, e) Input impedance, f) Output impedance, g) Gain, h) Gain-bandwidth product, i) Slew-rate, j) Saturation
2. (a) List the applications of Op-amp
(b) Describe how to use Op-amp to add voltages
3. (a) Define input impedance, output impedance, bandwidth, open-loop gain and closed – loop gain as applicable to Op-amp application
(b) Name the blocks and their functions of Op-amp
4. (a) Describe how difference amplifier can be realised using Op-amp
(b) Identify the 741 Op-amp pins and their functions

1. Explain the working of Schmitt trigger circuit using Op-amp; also, sketch the hysteresis plot
2. (a) Differentiate integrator and differentiator Op-amp circuits
(b) List the benefits of using Op-amp as an amplifier as compared to BJT
3. (a) Discuss the concept of precision rectification and its realization using Op-amp
(b) Construct Op-amp integrator and sketch its response for sinusoidal input
4. (a) Demonstrate how Op-amp can be used as voltage comparator
(b) Estimate the gain in the following circuit given Ri=1KΩ, Rf1=Rf2=10KΩ

1. (a) Identify the following Op-amp circuit and justify your identification

(b) Modify the Op-amp non-inverting amplifier into voltage follower with justification
2. Construct and label an inverting amplifier circuit for a voltage gain of 10 and dynamic output range of -10V to +10V. Sketch its response for the input, Vi=15cos(314t).
3. If Vin = 2V, find the output voltage and voltage gain for the circuit shown below


(a) If Vin = 2V, R1 = R2 = 1KΩ, find the output voltage and voltage gain for the below circuit.

(b) Sketch the output of the Op-amp inverter circuit for Vin= 2sin(2*pi*50*t) assuming power supply ±12V
5. For a summing amplifier shown below, (a) Find voltage gain if R1=R2=R3=1KΩ and Rf=5KΩ, (a) Estimate the output voltage if V1=1V, V2=V3=2V, R1=R2=10KΩ, R3=5KΩ and Rf=15KΩ, assuming power supply ±15V

Unit-4: Active filters and instrumentation amplifiers Five-mark Questions

1. Define active filter and mention its classification
2. List the applications of active filters
3. Describe how BPF can be realised using LPF and HPF
4. Describe PLL
5. Define passive filter, active filter, cut-off frequency, band width and frequency response with reference to filters

1. Illustrate how BEF can be realized using LPF and HPF
2. Distinguish between LPF and HPF
3. Compare BEF and BPF
4. Identify a circuit that can block low frequency signals and amplify high frequency signals and explain how it does.
5. Explain the need for instrumentation amplifier

1. Construct first order HPF filter with a cut-off frequency of 1KHz and sketch its frequency response
2. Calculate the cut-off frequency and gain of the following filter circuit given that R1=10KΩ, R2=2KΩ and C=0.01µF

3. Estimate the gain and cut-off frequencies of the following BPF given that C1= 0.01µF,
C2 = 1 μF, R1=1K and R2 ≈ 100 Ω

Ten-mark Questions

1. (a) Define active filter and list different filters based on frequency of filtering
(b) Describe the function of BEF with block diagram and frequency response plot
2. (a) Describe the operation of PLL
(b) List the applications of PLL and instrument amplifier

1. (a) Explain the working of instrumentation amplifier circuit
(b) Describe the working of BPF
2. (a) Explain the operation of PLL and mention its applications
(b) List the applications of the active filters
3. (a) Explain the working principle and frequency response of 1st order Butterworth LPF

1. (a) Design a first order Butterworth LPF circuit for a gain of 10, cut-off frequency of 160Hz
(b) Sketch the frequency response plot and circuit of a typical HPF
2. (a) Modify BPF filter to act as BEF at block diagram level and justify it
(b) List the advantages and disadvantages of active filters over passive filters


Unit-5: Wave-shaping circuits Five-mark Questions
1. List the applications of clippers and clampers
2. Select and write the circuit diagram to generate triggering pulses from square wave
3. Define positive clipper and briefly describe its working with a circuit diagram.
4. Describe how square wave can be converted into triangular wave with the relevant wave shaping circuit
5. Describe how DC level of AC waveform can be increased with a suitable circuit

1. Explain positive shunt clipper circuit using diode
2. Sketch and label the combinational clipping circuit
2. Write RC integrator circuit and plot its response for sinusoidal input
3. Compare clipper with clamping circuit
4. Distinguish between RC integrator with RC differentiator circuit

1. Write the output waveform of clipper circuit shown below for Vin = 10 sin (314t) assuming ideal diode

2. Determine and sketch the wave shaping circuit shown in the following block diagram

1.               Show how half-wave rectifier can be realised using clipper circuit.

Ten-mark Questions


1. Define Clipper. Explain simple positive and negative clipper circuits

2. Define clamper. Explain simple positive and negative clamper circuits

3. (a) List the applications of clippers and clampers

(b) Describe the working of RC integrator circuit


1. Explain positive and negative shunt clipper circuits using diode

2. (a) Differentiate clamper with clipper circuits

(b) Compare integrator with differentiator circuits

3. Demonstrate (a) Differentiator circuit as triggering pulse generator (b) Integrator as triangular waveform generator


1. Illustrate the operation of RC Differentiator and Integrator circuits with their response to square-wave signal.

2. Construct a clipper circuit to generate a signal having maximum positive amplitude of 2V and negative amplitude of -10V for a sinusoidal input of +10 to -10 V.

3. Write the output waveform of clipper circuit shown below for Vi=10 sin (314t)

4. Write the output waveform for the clipper circuit shown below assuming ideal diodes

5. Sketch the output waveforms for the circuit shown below for Vi=10 sin (314t) assuming
(a) Si diode (cut-in voltage 0.7V) and (b) Germanium diode (cut-in voltage 0.3V)

Unit-6: Sinusoidal oscillators Five-mark Questions
1. Define stability, open-loop gain, closed loop-gain, loop phase-shift and feedback as applicable to oscillators.
2. Draw Hartley oscillator circuit that generates 500KHz sine wave.
3. Compare RC oscillators with LC oscillators

1. Discuss the role of tank circuit in oscillator circuit
2. Relate Barkhausen criteria and sustained oscillations
3. Explain the role of RC network in RC phase-shift oscillator and write the expression for frequency of oscillation
4. Identify the oscillator to generate audio frequency oscillations and briefly describe it with circuit.
5. Sketch Wein-bridge oscillator circuit and state the role of bridge

1. Design LC circuit for Hartley and Collpits oscillators to oscillate at 600KHz
2. Sketch RC phase-shift oscillator circuit to oscillate at 10KHz
3. Explain the relation between sustained oscillations and Barkhausen criteria as applicable to oscillator circuit.
4. Calculate the frequency of oscillations in Hartley oscillator given that L1=0.03mH, L2=10µH and C=1µ. Suggest C1 value to generate same frequency using Collpits oscillator assuming C2=C and L=L2

Ten-mark Questions
1. (a) Draw RC phase-shift oscillator circuit with labelling
(b) Define loop gain and feedback. Explain the Barkhausen criterion
2. (a) Draw the crystal oscillator circuit with labelling (4)
(b) Define sustained, over-damped and under damped oscillations as applicable to oscillators (6)
3. (a) List the expressions for oscillating frequencies in Hartley, Collpits, RC phase-shift and Wein-bridge oscillators (8)
(b) State Barkhausen criterion (2)

1. (a) Explain the concept of positive feedback, open and closed-loop gains (6)
(b) Select Collpits oscillator tank circuit to oscillate at 500 KHz (4)
2. (a) Explain the working of Hartley oscillator using BJT
(b) Compare LC oscillators with RC oscillators
3. Compare the crystal oscillator with RC phase-shift and Hartley oscillator

1. Explain the working of Collpits oscillator using BJT. Illustrate how it can be converted  to Hartley oscillator
2. (a) Calculate the operating frequency of a Collpits oscillator circuit, if C1 = 0.027 µF, C2 = 0.027 µF, and L1 = 220 mH
(b) Illustrate how Collpits oscillator can be converted into Hartley oscillator
3. (a) Construct RC phase-shift oscillator to oscillate at 12KHz
(b) Compare Wein-bridge and Hartley oscillators

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