Home▸Physics & Mechanics▸How a Transformer Moves Power Across an Air Gap with No Wires Touching

⚡ Transformer Mutual Induction Lab

A 3D transformer with primary and secondary coils wound on a laminated iron core — adjust turns ratio and input voltage to watch magnetic flux link the coils and induce a stepped output voltage.

Physics & Mechanics3DModerate60 FPS

A primary coil and a secondary coil sit on opposite legs of a shared laminated iron core, linked only by a travelling magnetic flux — adjust the turns ratio, input voltage and load to see how a stepped output voltage is induced with no direct electrical contact.

🔬 What It Demonstrates

The animated pulses circling the core are the shared magnetic flux driven by the alternating primary current; that same flux, cutting through the secondary winding, induces an output voltage set purely by the turns ratio Nₛ/Nₚ.

🎮 How to Use

Change the primary and secondary turns to set a step-up or step-down ratio, adjust the input voltage and AC frequency, then connect the secondary load to watch current flow and the lamp light up.

💡 Did You Know?

With the load open, almost no current flows in either coil — only a tiny magnetising current sustains the flux, which is why an unloaded transformer left plugged in still barely draws any power.

⚙ Under the hood

Interactive 3D transformer model with primary and secondary coils where adjusting turns ratio and input voltage shows magnetic flux linking the coils to induce a stepped output voltage.

transformersmutual-inductionelectromagnetismmagnetic-fluxac-circuitsphysics

3D · Three.js / WebGL renderer · 60 FPS target · runs fully client-side, no install