Below, a Hall Effect sensor rests atop an electromagnet — 1″ in diameter, with 6/8″ wire coiled around another bolt. As the pendulum’s magnet accelerates towards the electromagnet’s core ...

A coil of wire, or solenoid, consists of a wire coiled up into a spiral shape. When an electric current flows, the shape of the magnetic field is very similar to the field of a bar magnet.

If the conductor is part of an electric circuit ... For example, if a magnet is moved into a coil of wire, the induced magnetic field tends to repel the magnet back out of the coil.

The device sure looks like an electromagnet made with magnet wire and a steel core ... aluminum has a copper ring embedded in it. The coil is fed with AC. The magnetic field from the coil induces ...