Faraday Homopolar Dynamo Tried out a simple faraday homopolar dynamo or electric generator. It consists of a disk spinning in a magnetic field. When the disc spins, an electric current I was produced which was in a direction perpendicular to the disk's velocity and perpendicular to the magnetic field direction. A current was produced even if the magnet which is the magnetic field source spins with the disk. The ammeter measuring the curent I has to have a low input coil wire resistance like 1ohm = R or less.