Topic
Charge and Current
This unit introduces the fundamental ideas of electric charge and current. Students explore how charges move, how current flows, and the principles that govern electrical circuits. By mastering these basics, learners gain the foundation needed for advanced topics in electricity and electronics.
Key Concepts
Charge and Current
Moving Charges
Kirchhoff’s First Law
Mean Drift Velocity
Milestones in the History of Electricity
c. 600 BC Thales of Miletus discovers that amber attracts feathers and other lightweight materials when rubbed – the first reference to static electricity.
1752 Benjamin Franklin suggests flying a kite in a thunderstorm to test whether lightning is a form of electricity.
1781 Luigi Galvani connected the nerves of a dead frog to a long metal wire during a thunderstorm and discovers “animal electricity”.
1800 Alessandro Volta constructs the voltaic pile – essentially a battery, so electricity was now available at the flick of a switch.
1821 Michael Faraday demonstrates an electric motor – useful work can now be extracted.
1880 Thomas Edison develops light bulbs that last 1200 hours – the race was now on to electrify a nation.
1897 Joseph Thomson discovers that cathode rays are negatively charged with a charge-to-mass ratio about 2000 times higher than the smallest known atom, he’d found the first sub-atomic particle.
1913 Robert Millikan shows that charge is quantised and the elusive properties of the electron are revealed!
Build Essential Electricity Skills
Electric charge and current are the starting point for everything electrical — from simple bulb circuits to complex electronic systems. Master the flow of electricity, build confidence, and connect physics to real‑world applications.
Justin’s lessons on charge and current were clear and engaging, making complex concepts easy to understand. Highly recommended!
I struggled with understanding electric current, but Justin’s clear explanations and examples helped me master the topic effortlessly.
Justin’s teaching on charge and current was outstanding. He broke down the concepts, making them accessible and interesting.
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