It’s an electromagnet pendulum analog circuit ... with electromagnets so they can move on to the next logical steps: coil guns and web shooters.

Increasing the number of turns on the coil of wire The image below illustrates a simple experiment to demonstrate electromagnetic induction. The direction of a motor effect force can be found ...

It is also grade school science to show that neither an electromagnet nor a permanent ... aluminum has a copper ring embedded in it. The coil is fed with AC. The magnetic field from the coil ...