EN1020 Circuits, Signals, and Systems

2026 · 3 credits · Department of Electronic and Telecommunication Engineering, University of Moratuwa

This module aims to equip the students with the fundamental tools of circuit analysis, signals, and systems.

Instructors: Ranga Rodrigo and Upeka Premaratne. Teaching assistant: Sanjana Kapukotuwa.
Schedule: Lectures: Tuesdays, 8:15 am to 10:15 am. Tutorials: Wednesdays, 3:15 pm to 5:15 pm.
Assessment: In-class quizzes (5 out of 8): 20%. Mid-semester examination: 20%. Final examination: 60%.
Links: Course outline Moodle page (enrolled students)

Lectures

The videos were recorded for EN1060 Signals and Systems, the earlier module that covered the same material.

#	Topic	Lecture notes	Videos	Tutorial
1	Introduction to signals and systems	Slides Handout	Lecture 01: Introduction
2	Signals	Slides Handout	Lecture 02a: Signals Lecture 02b: Complex Numbers Lecture 02c: Signals	Tutorial 01 Signals
3	Fourier series	Slides Handout	Lecture 03a: Fourier Series Lecture 03b: Fourier Series Properties	Tutorial 02 Fourier Series
4	Fourier transform	Slides Handout	Lecture 04a: Fourier Transform Lecture 04b: Fourier Transform Examples	Tutorial 03 Fourier Transform
5	Linear time-invariant systems	Slides Handout	Lecture 05a: Systems Lecture 05b: Convolution Sum Lecture 05c: Convolution Integral Lecture 05d: System Properties	Tutorial 04 Linear Time Invariant

All notes with their LaTeX sources are in the EN1020Lectures repository, and all videos are in the Signals and Systems playlist.

Syllabus

Circuit TheoryCircuit vs. wavelength, circuit as a graph/network. Charge, current, voltage, power, and energy. Units of measurement. LTI resistor, capacitor, and inductor. KCL and KVL. Ideal current and voltage sources, dependent sources, device modelling, RLC transient solutions using differential equations, concepts of transients vs. steady state. Resonance, mutual inductance, electromagnetic coupling, and analysis. Transformer as a coupled element.
Circuit Analysis Using Network TheoremsGround as a node, nodal analysis, Y matrix, node voltage and stimulus vector, super nodes, mesh analysis. Network theorems: superposition, Thevenin's, Norton's, Millman's. Source transformation and network equivalence, source transportation, substitution theorem, maximum power transfer, Y-Delta transformation. Two-port theory: impedance, admittance, hybrid, and ABCD parameters.
Introduction to Signals and SystemsClassification of signals as continuous-time, discrete-time and digital. Introduction to impulse and step functions. Introduction to systems and input-output relationships. Simple classes of signals such as sinusoid and exponential signals. Characterizing Linear Time-Invariant (LTI) systems. Overview of the analysis techniques applicable to each type of signal/system and their interrelationships.
Fourier SeriesOverview of Fourier analysis as the representation of signals with complex sinusoids. The Fourier series representation of periodic signals. Properties of the Fourier series. Characterizing LTI systems in the frequency domain. Introduction to Fourier transform.
Introduction to Fourier TransformContinuous-time Fourier transform, development of the Fourier transform representation, the Fourier transform for periodic signals.
Linear Time-Invariant (LTI) SystemsCharacteristics of LTI systems. Characterizing the input-output relationship of continuous- and discrete-time LTI systems in the time domain. The convolution theorem and its application to LTI systems. RLC circuit as an LTI system.