UNIT OVERVIEW

Every time you flip a light switch, charge your phone, or turn on the TV, you use electric circuits. This unit explains how electricity flows, why some devices need more power than others, and how circuits are designed.

In earlier work on electrostatics, you learned about stationary charges. Now we set those charges in motion. When charges flow continuously through a conductor, we have an electric current.

By the end of this unit, you will be able to:

• Explain electromotive force (emf), potential difference, and current
• Measure voltage using a voltmeter and current using an ammeter
• Apply Ohm's Law to calculate resistance, current, and voltage
• Analyse circuits with resistors in series and parallel
• Calculate equivalent resistance in combination circuits
• Conduct experiments with electric circuits
• Solve real-world circuit problems

Real-life applications:

1. Load shedding: When electricity demand exceeds supply, circuits must be protected from overload. Understanding resistance and current helps explain why certain appliances draw more power.