US Patent 7710227 Electromagnetic energy transducer

An electromagnetic energy transducer comprising a permanent magnet (1), a soft-magnetic element (9), an electrical coil (6) and stop points (8a-8d). The electrical coil surrounds a part of the magnetic circuit, wherein the permanent magnet (1) and the soft-magnetic element (9) are arranged to form a magnetic circuit with a first flux direction. At least one of the soft-magnetic element (9) and the permanent magnet (1) is mounted for rotary movement about an axis (4) with respect to the other. End points of the rotary movement are formed by the stop points (8a-8d).