The rotary machine's motor moves a rotating circular ... But as the metal arm touches the coil, another thin piece of metal loses contact with a circuit screw, breaking the current and causing ...

They are quiet, reliable, invisible machines. Perhaps his most ... The secondary coil contains thousands of turns of thin wire. This steps up the voltage to between 100,000 and 1,000,000 volts.

Coils can be wound by hand, of course, but reliably creating perfect coils with thin wire and lots of layers requires some additional help. Happily, [Drew] shares his method for doing exactly that.