Slip rings maintain constant contact with the same sides of the coil As one side of the coil moves up through the magnetic field, a potential difference is induced (created) in one direction.

This project combines some of the most exciting aspects of DIY experiments. Lego, high voltage, and a powerful magnetic field. The idea is simple yet intriguing, using a copper coil, capacitors, and a ...

Note that this magnetic field opposes the original change. 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.