To demonstrate a simple AC/DC generator.
AC/DC generator with projection meter on overhead projector.
The generator consists of a coil which rotates through an appropriately shaped magnet, which is powered by a 1.5 volt battery. Turning the crank generates either an AC voltage, using a double commutator, or DC voltage, using a split ring commutator. The commutator must be set manually for each case. The output is displayed by a projection meter.