ENEE 154 — Electrical Circuits and Machines
Exam-oriented study notes, rigorous step-by-step derivations, verified numerical standard solutions, and in-depth PYQ analysis from 2081 Ashwin to 2083 Baishakh.
All 9 chapters summarized with variables, units & constraints.
Every core derivation with assumptions, algebraic steps & PYQ frequency.
4 full exam papers fully solved with step-by-step calculations.
Must-know concepts, common calculation traps & rapid roadmap.
1. Official Syllabus Weightage & Exam Blueprint
According to the official Tribhuvan University Institute of Engineering (IOE) curriculum for ENEE 154 (BEI / BCT), the final theoretical examination carries 60 marks (Pass Mark: 24, Time: 3 hours).
| Chapter # | Chapter Name | Teaching Hours | Expected Marks | Priority Level | Typical Exam Question Type |
|---|---|---|---|---|---|
| 1 | Transients in Electric Circuit | 7 hrs | 7 M | High | Nodal/Mesh with dependent sources [6M] + Initial conditions \(i(0^+), di/dt\) [5M] |
| 2 | Classical Transient Analysis (R-L-C) | 10 hrs | 10 M | High | Differential equation derivation + step/exp excitation numerical [6M] |
| 3 | Transient Analysis Using Laplace Transform | 7 hrs | 7 M | High | Transformed s-domain circuit with initial generators [6M] |
| 4 | Network Transfer Function & Bode Plot | 8 hrs | 8 M | High | Asymptotic Bode magnitude & phase plot [7-8M] |
| 5 | Two-Port Parameters of Network | 8 hrs | 8 M | High | Parameter evaluation (Z/ABCD/h) + Conversion/Cascade derivation [5-6M] |
| 6 | Magnetic Circuit and Induction | 3 hrs | 3 M | Medium | Series-parallel magnetic circuit with air gap numerical or short note [3-5M] |
| 7 | Transformers | 6 hrs | 6 M | High | Constancy of core flux proof [5M] + OC/SC test numerical or efficiency [5M] |
| 8 | DC Machine | 5 hrs | 5 M | High | Torque derivation & Back EMF [4+2M] + Speed control numerical [5-6M] |
| 9 | AC Motor | 6 hrs | 6 M | High | RMF production proof [5M] + Torque-slip curve + Slip calculation [5-6M] |
| TOTAL | 60 hrs | 60 Marks | - | Attempt ALL 10 Questions (with internal choice in Q10) | |
The official syllabus notes: "There may be minor deviation in marks distribution." In actual past papers (2081 Ashwin, 2082 Baishakh, 2082 Bhadra, 2083 Baishakh), questions 1–4 consistently test Circuit Analysis & Transients (23–24 marks), questions 5–6 test Frequency Response & Two-Port Parameters (13–14 marks), and questions 7–10 test Machines & Electromagnetics (23–24 marks).
2. Recommended Learning Sequence
To score top marks in IOE engineering examinations, do not memorize final answers or problem solutions blindly. Follow this seven-phase sequence:
3. Major Exam Trends Identified Across 2081–2083 Papers
Appears every semester in Question 2 for 5 marks. In fact, the exact same two-mesh circuit with a \(1\text{H}\) inductor, \(10\,\Omega\) resistors, and \(1\text{F}\) capacitor was repeated in 2081 Ashwin and 2083 Baishakh!
Always carries 7 or 8 marks. Features double poles at the origin (\(1/s^2\)), quadratic poles, or left-half plane zeros. Requires systematic corner frequency tables and magnitude/phase slope sketches.
The proof that "main magnetic flux in transformer core is independent of load" appeared in 2081 Ashwin, 2082 Bhadra, and 2083 Baishakh. OC/SC test parameter calculation appeared in 2082 Baishakh.
Conceptual justification of why DC motors draw huge starting current and how a 3-point starter protects the armature, along with speed control numerical calculations (\(N \propto E_b/\Phi\)).
4. Jump Directly to Chapters
Dependent source nodal/mesh analysis, initial condition evaluation at \(t=0^+\).
First and second order ODEs, complementary functions, particular integrals.
Transformed element models, initial condition generators, partial fractions.
Poles, zeros, asymptotic Bode magnitude and phase plotting, passive filters.
Z, Y, ABCD, h parameter calculations, cascade interconnection, reciprocity.
Reluctance, air gap MMF calculation, hysteresis & eddy current losses.
EMF equation, core flux constancy, equivalent circuit, OC/SC testing, efficiency.
EMF and torque equations, back EMF, 3-point starter, speed control methods.
Rotating magnetic field proof, torque-slip curves, 1-phase starting, stepper/BLDC.