The armature coil rotates in a permanent magnetic field, generating alternating current with periodic direction changes and varying electromotive force. AC power is output via collector ring and brushes; moving brushes to the copper half-ring converts it to DC for versatile demonstration purposes. To demonstrate the alternator, connect brushes to the ring and use a sliding rheostat with a DC ammeter to form an external circuit for clear current observation. This instrument includes a permanent magnet, stator, rotor, brush, baseplate, and manual mechanism for generating and controlling magnetic fields and rotation. Connect the generator output to a DC voltmeter or ammeter; slowly rotate the rotor to observe current direction changes in educational setups.