Hysteresis curve of an iron core
This experiment enables your smartphone to qualitatively measure the hysteresis curve of an iron core. The iron core is sitting inside a coil. By running a current through the coil the iron core is magnetised. When plotting the current running through the coil against the magnetic field of said coil, a hysteresis effect becomes visible. The current is indirectly measured by the magnetic field of a second coil without iron core, set in a different axis.
Smartphone (with Phyphox and Magnetic sensors) 2 coils (same windings e.g. 300) iron core (non-folded) cross switch adjustable power supply (current continuously adjustable)