Electronics · Capacitors and coils / Principles and inquiry
Electromagnet strength experiment guide
Compare magnetic strength and pole direction as you change turns, current and the iron core.
How does it work?
Air-core field is proportional to NI; an iron core saturates and its increase slows.
Key relationship
Bair = μ₀NI/ℓ · Bcore = Bsat tanh(100Bair/Bsat)
Try this investigation
- Compare magnetic strength and pole direction as you change turns, current and the iron core.
- Run and record each of the three baseline presets.
- Compare the changed variable and its result with the baseline records.
Interpreting your results
What happens to the poles if only the direction of the same current is reversed?
N ↔ S
Assumptions and limitations
This is a long-solenoid approximation. Core hysteresis and the actual mechanics of clip lifting are omitted. Experiment on screen; do not reproduce this with real power supplies, outlets or high voltage.