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ENEE 154Bachelor in Computer Engineering · Semester 21 Paper Available

Electrical Circuits and Machines

Past examination question papers and complete curriculum syllabus for Electrical Circuits and Machines (ENEE 154), Bachelor in Computer Engineering Semester 2 under Institute of Engineering (IOE), Tribhuvan University.

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2nd-sem_Electrical Circuits and Machines.pdf

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Most Frequently Asked Questions

Top recurring IOE board exam questions for Electrical Circuits and Machines with verified mark schemes, formula notation, and recurrence frequency.

Showing 30 of 30 top repeated questions

Transients in Electric Circuit

1 Question
#1Repeated 2 Times[5 Marks]Transients in Electric Circuit
Obtain the value of $i_1$, $i_2$, $di_1/dt$, $di_2/dt$ at $t=0^+$, if the switch is closed at $t=0$ in the given circuit.
Appeared in:2083 Baishakh2081 Ashwin

Transient Analysis R-L-C Circuit by Classical Method

3 Questions
#1Repeated 1 Times[6 Marks]Transient Analysis R-L-C Circuit by Classical Method
Derive the differential equation of series RLC circuit when excited by step voltage and discuss the different cases of circuit responses.
Appeared in:2082 Bhadra
#2Repeated 1 Times[6 Marks]Transient Analysis R-L-C Circuit by Classical Method
Derive the expression of current in series RC circuit excited by exponential voltage source by using classical method.
Appeared in:2083 Baishakh
#3Repeated 1 Times[6 Marks]Transient Analysis R-L-C Circuit by Classical Method
A DC source of 100 V is suddenly applied at time $t = 0$ to a series RLC circuit comprising $R = 2\,\Omega$, $L = 0.5\text{ H}$ and $C = 1\text{ F}$. Obtain the expression for current in the circuit by using classical method.
Appeared in:2082 Baishakh

Transient Analysis Using Laplace Transform

4 Questions
#1Repeated 2 Times[8 Marks]Transient Analysis Using Laplace Transform
Explain the initial and final value theorems in Laplace domain. A series RL circuit with $R = 10\,\Omega$ and $L = 2\text{ H}$ is connected to a DC voltage source of $100\text{ V}$ at $t = 0$. Find the current $i(t)$ using Laplace transform.
Appeared in:2082 Bhadra2080 Chaitra
#2Repeated 2 Times[8 Marks]Transient Analysis Using Laplace Transform
A parallel RLC circuit with $R = 5\,\Omega, L = 0.5\text{ H}, C = 0.1\text{ F}$ is excited by an impulse current source $i_s(t) = \delta(t)$. Determine the voltage $v(t)$ across the circuit using transformed network analysis.
Appeared in:2081 Chaitra2078 Chaitra
#3Repeated 1 Times[6 Marks]Transient Analysis Using Laplace Transform
In the circuit shown, switch is changed from position a to position b at $t = 0$. Determine the current $i(t)$ using Laplace transform method.
Appeared in:2082 Bhadra
#4Repeated 1 Times[6 Marks]Transient Analysis Using Laplace Transform
An exponential voltage $V(t) = 20e^{-4t}$ is suddenly applied at time $t = 0$ to series RLC circuit comprising $R = 2\,\Omega$, $L = 0.5\text{ H}$ and $C = 1\text{ F}$. Obtain the expression for the current $i(t)$ in the circuit using Laplace method.
Appeared in:2082 Baishakh

Network Transfer Function and Frequency Response

1 Question
#1Repeated 4 Times[7 Marks]Network Transfer Function and Frequency Response
What is network function? Define poles and zeros of network function. Construct the asymptotic magnitude Bode plot and phase plot for the given transfer function: $H(s) = \frac{10(s^2+8s+15)}{s^2(s+3)(0.05s+1)}$.
Appeared in:2083 Baishakh2082 Bhadra2082 Baishakh2081 Ashwin

Two-Port Parameters of Network

4 Questions
#1Repeated 2 Times[6 Marks]Two-Port Parameters of Network
Find Z parameter for given two port network and state whether network is symmetrical or reciprocal.
Appeared in:2083 Baishakh2082 Bhadra
#2Repeated 2 Times[6 Marks]Two-Port Parameters of Network
Find the expression of hybrid parameters in terms of Z parameters. Derive the equivalent T parameters of two cascade connected two port networks.
Appeared in:2082 Baishakh2081 Ashwin
#3Repeated 2 Times[8 Marks]Two-Port Parameters of Network
Define $z$-parameters, $y$-parameters, $h$-parameters, and $ABCD$ transmission parameters of a two-port network. Derive the condition of reciprocity and symmetry for $z$-parameters and $ABCD$-parameters.
Appeared in:2082 Bhadra2081 Chaitra
#4Repeated 2 Times[6 Marks]Two-Port Parameters of Network
Derive the relationship expressing $z$-parameters in terms of $y$-parameters and $h$-parameters.
Appeared in:2081 Chaitra2079 Chaitra

Magnetic Circuit and Induction

2 Questions
#1Repeated 2 Times[6 Marks]Magnetic Circuit and Induction
Define magnetomotive force (MMF), magnetic flux, reluctance, and permeance. Compare a magnetic circuit with an electric circuit highlighting similarities and differences.
Appeared in:2082 Bhadra2081 Chaitra
#2Repeated 2 Times[6 Marks]Magnetic Circuit and Induction
Explain self-inductance, mutual inductance, and coefficient of coupling $k$. Derive the relationship $M = k\sqrt{L_1 L_2}$ between mutual inductance and self-inductances of two magnetically coupled coils.
Appeared in:2081 Chaitra2079 Chaitra

Transformers

6 Questions
#1Repeated 2 Times[5 Marks]Transformers
List out features of ideal transformer. Show that main magnetic flux in the transformer core is independent of load current.
Appeared in:2083 Baishakh2081 Ashwin
#2Repeated 2 Times[6 Marks]Transformers
Derive the EMF equation of a single-phase transformer. Why is the transformer core laminated?
Appeared in:2082 Bhadra2080 Chaitra
#3Repeated 2 Times[8 Marks]Transformers
Draw the exact and approximate equivalent circuits of a single-phase transformer referred to the primary side. Explain open circuit (OC) and short circuit (SC) tests used to determine equivalent circuit parameters.
Appeared in:2082 Bhadra2081 Chaitra
#4Repeated 2 Times[6 Marks]Transformers
Derive the condition for maximum efficiency of a transformer. Prove that maximum efficiency occurs when variable copper loss equals constant iron loss.
Appeared in:2081 Chaitra2078 Chaitra
#5Repeated 1 Times[5 Marks]Transformers
The following test results were obtained on 20 kVA, 2200/220 V, 50 Hz, single phase transformer: O.C test: 220 V, 1.1 A, 125 W (On LV side) S.C test: 52.7 V, 8.4 A, 287 W (On HV side) Calculate the equivalent circuit parameters referred to secondary side.
Appeared in:2082 Baishakh
#6Repeated 1 Times[5 Marks]Transformers
A 150 kVA single phase transformer has an iron loss of 700 W and a full load copper loss of 1800 W. Calculate the copper losses, iron losses, output power and efficiency of transformer at 0.8 power factor lagging when secondary is 25% overloaded.
Appeared in:2082 Bhadra

DC Machine

6 Questions
#1Repeated 2 Times[5 Marks]DC Machine
State the role of commutator and carbon brushes in DC machine. Explain the characteristics of DC generators.
Appeared in:2082 Bhadra2081 Ashwin
#2Repeated 2 Times[8 Marks]DC Machine
Derive the torque equation and back-EMF equation of a DC machine ($E_b = \frac{P \Phi Z N}{60 A}$). Explain the significance of back-EMF in a DC motor.
Appeared in:2082 Bhadra2080 Chaitra
#3Repeated 2 Times[6 Marks]DC Machine
Explain why a DC series motor should never be started on no-load. Draw the torque-speed and torque-current characteristics of DC shunt and series motors.
Appeared in:2082 Bhadra2081 Chaitra
#4Repeated 2 Times[6 Marks]DC Machine
Explain armature reaction in DC machines and its undesirable effects (cross-magnetization and demagnetization). How is armature reaction neutralized using compensating windings and interpoles?
Appeared in:2081 Chaitra2079 Chaitra
#5Repeated 1 Times[6 Marks]DC Machine
Explain the production of torque in DC motor with necessary mathematical explanation and derivation. What is the role of back emf in DC motor?
Appeared in:2082 Baishakh
#6Repeated 1 Times[5 Marks]DC Machine
A shunt generator supplies 96 A at a terminal voltage of 200 V. The armature and shunt field resistance are $0.1\,\Omega$ and $50\,\Omega$. The iron and frictional losses are 2500 W. Find (a) emf generated, (b) commercial efficiency.
Appeared in:2083 Baishakh

AC Motor

3 Questions
#1Repeated 2 Times[6 Marks]AC Motor
How does three phase induction motor start? Why speed of this motor never reaches synchronous speed?
Appeared in:2082 Bhadra2082 Baishakh
#2Repeated 2 Times[8 Marks]AC Motor
Explain the working principle of a 3-phase squirrel cage induction motor with the concept of rotating magnetic field (RMF). Define slip and derive the expression for rotor frequency $f_r = s f$.
Appeared in:2082 Bhadra2081 Chaitra
#3Repeated 1 Times[6 Marks]AC Motor
Explain the Torque-speed characteristics of three phase induction motor with the help of proper mathematics and graph.
Appeared in:2081 Ashwin

Curriculum Syllabus & Course Topics

Sourced from TU curriculum portal
Full Syllabus (PDF)
Chapter-wise Units & Micro-Syllabus Topics (9 Units)

  1. 1. Transients in Electric Circuit

    • 1.1Characteristics of various network elements
    • 1.2Nodal analysis with dependent and independent sources
    • 1.3Mesh analysis with dependent and independent sources
    • 1.4Application of matrix method in network analysis
    • 1.5Procedure of evaluating initial conditions
    • 1.6Initial values of derivatives
    • 1.7Initial condition in the case of R-L-C network

  2. 2. Transient Analysis R-L-C Circuit by Classical Method

    • 2.1Introduction
    • 2.2First order differential equation with constant coefficient
    • 2.3Higher order homogenous and non-homogenous differential equation with constant coefficient
    • 2.4Particular integral by method of undetermined coefficient
    • 2.5Response of R-L and R-C circuits with DC excitation
    • 2.5.1DC excitation
    • 2.5.2Exponential excitation
    • 2.5.3Sinusoidal excitation
    • 2.6Response of Series R-L-C circuits with
    • 2.6.1DC excitation
    • 2.6.2Exponential excitation
    • 2.6.3Sinusoidal excitation
    • 2.7Response of Parallel R-L-C circuits with
    • 2.7.1DC excitation
    • 2.7.2Exponential excitation

  3. 3. Transient Analysis Using Laplace Transform

    • 3.1Introduction
    • 3.2Response of R-L and R-C circuits with
    • 3.2.1DC excitation
    • 3.2.2Exponential excitation
    • 3.2.3Sinusoidal excitation
    • 3.3Response of series R-L-C circuits with
    • 3.3.1DC excitation
    • 3.3.2Exponential excitation
    • 3.3.3Sinusoidal excitation
    • 3.4Response of parallel R-L-C circuits with
    • 3.4.1DC excitation
    • 3.4.2Exponential excitation

  4. 4. Network Transfer Function and Frequency Response

    • 4.1Concept of complex frequency
    • 4.2Transfer functions of two port networks
    • 4.3Poles and zeros of networks
    • 4.4Magnitude and phase response
    • 4.5Bode diagrams
    • 4.6Band width, high-q and low-q circuits
    • 4.7Basic concept of filters: High-pass, low-pass, band-stop and band-pass filters

  5. 5. Two-Port Parameters of Network

    • 5.1Definitions of two-port networks
    • 5.2Parameters of two-port networks
    • 5.2.1Open circuit impedance parameters
    • 5.2.2Short circuit admittance parameters
    • 5.2.3Transmission line parameters
    • 5.2.4Inverse transmission line parameters
    • 5.2.5Hybrid parameters
    • 5.2.6Inverse hybrid parameters
    • 5.3Relationship and transformation between sets of parameters
    • 5.4Interconnection of two port networks
    • 5.5Condition for reciprocity and symmetry

  6. 6. Magnetic Circuit and Induction

    • 6.1Magnetic circuit and its types
    • 6.2B-H relationship and hysteresis with DC excitation
    • 6.3Hysteresis with AC excitation
    • 6.4Hysteresis loss and Eddy current loss
    • 6.5Faraday’s law of electromagnetic induction, statically and dynamically induced EMF
    • 6.6Force on current carrying conductor

  7. 7. Transformers

    • 7.1Construction, operating principle and EMF equation of single-phase transformer
    • 7.2No load and load operation of transformer
    • 7.3Equivalent circuit diagram of transformer
    • 7.4Transformer testing (Open circuit and short circuit)
    • 7.5Voltage regulation, losses, efficiency and condition for maximum efficiency
    • 7.6Auto transformer, Isolation transformer

  8. 8. DC Machine

    • 8.1Constructional details of DC machine
    • 8.2Operating principle and EMF equation of DC generator
    • 8.3Operating principle and torque equation of DC motor
    • 8.4Types of DC machine
    • 8.5Back EMF and its role in DC motor
    • 8.6Performance characteristics of DC motor
    • 8.7Starting of DC motor using 3-point starter
    • 8.8Speed control of DC motor (Armature control, field control)
    • 8.9Losses and efficiency

  9. 9. AC Motor

    • 9.1Construction, production of rotating magnetic field and operating principle of three-phase induction motor
    • 9.2Torque equation of three-phase induction motor at standstill and running condition
    • 9.3Torque slip characteristics, condition for maximum torque and effect of rotor resistance on torque slip characteristics
    • 9.4Single-phase induction motor
    • 9.5Double field revolving theory
    • 9.6Starting of single-phase induction motor (Capacitor start and run, shaded pole)
    • 9.7Introduction to permanent magnet brushless DC motor, hysteresis motor, stepper motor, servo motor, universal motor

Examination Scheme & Marks Distribution

Evaluation Structure

  • Final Board Theory Exam: 60 Marks (Pass mark: 24)
  • Internal Assessment: 40 Marks (Pass mark: 16)
  • Practical / Lab Exam: 25 or 50 Marks (Continuous lab evaluation + viva, where applicable)

* This is the general current IOE 60/40 scheme; verify course-specific details in the syllabus above.

Exam Preparation Guidelines

  • Review the available past examination paper to understand question styling, typical derivation topics, and marks allocation.
  • Practice drawing labeled circuit schematics, deriving transfer functions, and showing systematic mathematical steps.
  • Structure answers with labeled diagrams, concise bullet points, and highlight final answers in numerical solutions.

Frequently Asked Questions (Electrical Circuits and Machines)

Q: How can I download Electrical Circuits and Machines past question papers?

You can preview or download the Electrical Circuits and Machines question papers (PDF) directly using the built-in viewer on this page with zero redirects or paywalls.

Q: What is the pass mark for Electrical Circuits and Machines?

The general current scheme is a 60-mark final theory exam and a 40-mark internal assessment, with pass marks of 24 and 16. Verify the course-specific syllabus above.

Q: Where can I find the complete syllabus for this subject?

The available chapter-wise syllabus and topic breakdown is indexed in the Syllabus section above, with links to the curriculum PDF source.

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