Hamilton 500

The world's first battery-powered wristwatch movement, introduced January 3, 1957. Revolutionary 'moving coil' electric system where a wire coil mounted on one side of the balance wheel interacts with permanent magnets. Power comes from a small button cell battery (developed with National Carbon Company/Energizer) providing approximately one year of operation. Features extremely delicate contact wire/trip spring assembly requiring precise adjustment. Contact points physically make and break the circuit 18,000 times per hour. Used in the iconic Hamilton Ventura and other Electric models. Superseded by improved 500A and 505 calibers.