The one that [Made in Poland] chose to sacrifice was particularly nasty and greasy, but after popping off the pulley, the treasure within was revealed: the large, ring-shaped clutch electromagnet.

A coil with an iron core is called an electromagnet. The iron core increases the coil’s magnetic field strength. A simple electromagnet is made by coiling wire around an iron nail. An iron core ...

It’s an electromagnet pendulum analog circuit. Whether you’re building it, or just studying the schematics, this is a fun way to brush up on the non-digital side of the craft. The pendulum is ...