An electrical generator includes a rotary disk that is made of plastic injection molding in which a plurality of coils each having an exposed contact is embedded. Two stationary disks are arranged on opposite sides of the rotary disk and each has an inside surface that opposes the rotary disk and carries two semi-circular magnets. The rotary disk is fixed to a shaft having opposite ends fit into bearings that are received in central bores defined in the stationary disks. The coils are each formed by winding a wire in at least one turn in the form of a circle or an ellipse, the turns being coincident with each other or partially offset with respect to each other. Or alternatively, the coils are formed concentric with respect to each other and the rotary disk.