OBSERVATION CHAMBER / ACTIVE
Electromagnetic Induction Observatory
Rotate a coil in a uniform magnetic field. Observe magnetic flux, induced voltage, current, and the work supplied against electromagnetic torque.
ROUTE 99 / FIELD
From changing flux to resistor heat
An external drive keeps the angular velocity fixed. Follow the coil normal n, magnetic field B and signed current I. The plot shows the full 12-second observation window.
Focus the diagram: Space/P = play or pause; S = step; R = reset; L = next plot. The drawing is schematic; time is in seconds.
LIVE NUMERICAL READINGS
Flux, force and energy
- t / s
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- θ / rad
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- Φ / Wb (1 turn)
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- Ψ / Wb turns
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- ε / V
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- I / A
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- τem / N m
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- Pext / W
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- Pjoule / W
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- Wext / J
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- Qjoule / J
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- Pext − Pjoule / W
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- Wext − Qjoule / J
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- FINITE
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θ is the angle from the fixed positive reference field axis to the coil normal n. B is the signed magnetic-field component along that axis. The right-hand rule about n defines positive current. Electromagnetic torque opposes rotation. External work becomes heat because self-inductance is zero.
DETERMINISTIC CHECKS
Check the balance —
| CHECK | ERROR | LIMIT | RESULT |
|---|
Central differences test Faraday’s law. Simpson integration over one period tests Joule heat independently of the analytic time integral. Signed reversal, zero speed and resistance scaling are also checked.
Current observation report
OBSERVATION GUIDE
Observe changes and signs
- Step from the oblique preset. Compare flux linkage and induced voltage. Their peaks occur at different angles.
- Set ω to zero. Flux can remain nonzero while voltage, current and torque vanish. Reverse B or ω and compare the signs.
- Double R. Current and Joule power both halve at the same angle and speed. Compare external power with heat generation.
- REPORT and PNG pause playback. Parameter, plot, step and reset changes clear old output. Hidden tabs stop without automatic restart. Reduced motion disables PLAY; STEP remains available.
Runs in this browser. No upload or registration.
MODEL AND SCOPE
A prescribed rotating coil
θ = θ₀ + ωt; Φ = BA cos θ; Ψ = NΦ
ε = −dΨ/dt = NBAω sin θ; I = ε/R
τem = −NBA I sin θ
Pext = −τemω = εI = I²R ≥ 0
Wext = Qjoule = ∫₀ᵗ I²R dt
A planar coil rotates in a uniform, static magnetic field and a pure resistance R. This quasistatic model assumes zero self-inductance. The external drive compensates for electromagnetic torque and keeps ω fixed. It omits changes in speed from back reaction, field propagation, radiation and a full Maxwell solution.
Schematic observation only. Not a real-device measurement, generator design or performance prediction.
OBSERVATION POLICY
This prescribed rotating-coil model runs in your browser. Inputs, calculations, reports, and images stay local. It does not measure a real coil or design an electrical device.
Route
This chamber belongs to Fields in Motion.
FIELD Back to Fields in Motion Route.