Singapore H2 Physics: Build an AC Generator from Scratch (9478 Paper 4)

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Q: What does Building an AC Generator from Scratch: Electromagnetic Induction for H2 Physics cover?
A: Wind your own coils, spin magnets, and generate real electricity.
TL;DR Build a working AC generator with $20 of materials: magnets, wire, and a drill. Generate measurable voltage, see sinusoidal waveforms on your phone, verify Faraday's law quantitatively, and understand why mains electricity is AC not DC. Perfect for demonstrating electromagnetic induction beyond textbook diagrams.

Quick build map

  • TL;DR: A spinning magnet near a coil makes an AC voltage.
  • Materials and Tools: You need magnets, magnet wire, a rotor, a base, and a multimeter.
  • Building Your Generator: Build the rotor, wind the coil, mount everything close together, then test the output.

Keep the rest of your hands-on builds organised in our H2 Physics Experiments hub.

Revising the full topic set? Pair this lab with the notes and drills at https://eclatinstitute.sg/blog/h2-physics-notes and keep scholarship ideas handy via https://eclatinstitute.sg/blog/scholarships/matcher if you convert the experiment into a competition or portfolio piece.

From Faraday to Your Phone Charger

Every electrical device you own exists because Faraday discovered that changing magnetic flux induces voltage. Your DIY generator will demonstrate:

  • How motion creates electricity
  • Why power stations use AC
  • The link between frequency and rotation speed
  • Why more coils = more voltage

Plus, there's something magical about lighting an LED with your own hand-wound generator.

Concrete example: what one reading means

Suppose the drill spins the magnet set faster and the phone oscilloscope trace shows taller peaks. The idea to write in your report is simple: faster rotation means the magnetic flux through the coil changes more quickly, so dΦ/dtd\Phi/dt

Chee Wei Jie
Reviewed by
Chee Wei Jie·Academic Advisor (Physics)

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