Moving-Coil Galvanometer Simulation

A moving-coil galvanometer is a coil of fine wire hung between curved magnet poles around a soft iron core. The poles and core make the field radial, so the coil's sides always cross it at right angles and the torque on the coil is NIAB at every angle. A spring twists back, and the coil settles at an angle proportional to the current — giving a linear scale.

This galvanometer simulation has a 3D model you can turn, with the current, forces and field shown, and two tabs that convert it into the meters you use in the lab: an ammeter (a small shunt in parallel) and a voltmeter (a large resistance in series), stepping through why each works.