Alternating Current Theory - Physics (Undergraduate Foundation)

The electricity in your wall socket does not flow in one direction like a battery; it reverses direction many times every second. This course teaches the essential physics of Alternating Current (AC) by examining how voltage and current vary as sine waves. You will learn to calculate peak and Root Mean Square (RMS) values to determine the actual power used by appliances. We analyse how inductors and capacitors oppose current through reactance and how these elements combine with resistors to form total impedance in RLC circuits. AC Power is the global standard for homes and industries because it moves efficiently over long distances. For anyone in civil, mechanical, or electrical engineering, mastering AC theory is mandatory. This knowledge applies directly to designing power grids, maintaining factory motors, and managing household wiring. You will understand how to handle electrical loads and ensure equipment operates safely within professional infrastructure projects. You will learn to derive and use formulas for AC voltage and current. The course teaches you to find the relationship between peak and RMS values for accurate power measurements. You will gain the skills to calculate inductive and capacitive reactance and solve for the total impedance of RLC circuit combinations. By the end, you will understand phase differences and how they affect the efficiency of electrical systems. This module targets undergraduate engineering and physics students requiring a firm grasp of circuit dynamics. It also assists technical college students and secondary school leavers preparing for university-level science. Beyond formal students, anyone interested in how modern power systems function will find this useful. It provides the technical literacy needed to bridge the gap between classroom physics and industrial application.

Enrolment valid for 12 months

This course is also part of the following learning track. You may join the track to gain comprehensive knowledge across related courses.

PHY 102: General Physics II - Electricity and Magnetism

Electricity and magnetism run every home, factory, and phone all over the world. This track builds the technical foundation to master laws governing electrical energy and signals. You will progress from stationary charges to alternating current and electromagnetic waves. It simplifies the NUC CCMAS syllabus into actionable knowledge for solving practical technical problems. The programme is for first-year university and polytechnic students in engineering or physical sciences. It also serves school leavers preparing for university physics or technical entrance exams. Science teachers and technicians who need a solid refresher on core electrical principles will find the material direct and relevant to their work. You will learn to calculate electrical forces, design functional DC and AC circuits, and predict how magnetic fields drive motors and generators. You will master the use of Gauss's Law, Kirchhoff's rules, and Maxwell's equations to solve engineering challenges. Completing this track ensures success in PHY 102 exams and prepares you for a career in power systems, telecommunications, or renewable energy.

Course Chapters

1. Introduction

This chapter introduces the fundamental properties of alternating current and how it differs from direct current. You will understand why AC is the global standard for power transmission and how to measure its time-varying values. You will define sinusoidal voltage and frequency; master the conversion between peak and root mean square values; and calculate the effective power equivalent of AC signals.

Concept Overviews

4 Lessons

Problem Walkthroughs

3 Lessons

2. AC Reactance

This chapter examines how inductors and capacitors oppose alternating current in ways that resistors cannot. You will learn how frequency affects the flow of electricity through different circuit components. You will calculate inductive and capacitive reactance; understand the phase shift between voltage and current; and determine the frequency response of reactive elements.

Concept Overviews

4 Lessons

Problem Walkthroughs

3 Lessons

3. Phasors and Impedance

This chapter teaches you to combine resistance and reactance using vector-like diagrams called phasors. You will learn to calculate the total opposition to current in complex circuits. You will master phasor diagrams; calculate the total impedance of RLC series and parallel circuits; and determine the phase angle between source voltage and circuit current.

Concept Overviews

4 Lessons

Problem Walkthroughs

3 Lessons

4. Power and Resonance

This chapter covers electrical efficiency and the unique condition where inductive and capacitive effects cancel out. You will learn to measure useful work versus energy lost in a system. You will calculate true and apparent power; determine the power factor of industrial loads; and find the resonant frequency of RLC tuning circuits.

Concept Overviews

4 Lessons

Problem Walkthroughs

4 Lessons

5. Conclusion

This final chapter reviews the principles of alternating current dynamics and power measurement. It bridges the gap between basic circuit laws and industrial electrical applications. You will summarise the core laws of reactance and impedance and prepare for advanced studies in power engineering and electronic signal processing.

Concept Overviews

1 Lesson