| 摘要 |
A moving coil transducer has its diaphragm, which is of thin aluminium, made in two parts, one of which is a central circular part (14) while the other is an annular outer part (11). The central part carries the coil (18), on a cylindrical portion (16), and the outer part has another cylindrical portion (12). When the diaphragm is assembled the two cylindrical portions (11, 12) together enclose the coil. The magnetic circuit has a central hollow portion (3) with a flat disc at one end which supports an annular magnet (5). There is another disc (6) on the other end of the magnet (5), which disc's inner edge defines with the end of the pole piece portion (3) the air gap for the coil. In another version the outer pole is a flat disc with a circumferential wall carrying an annular pole-piece whose inner rim is the outside of the air gap. A cylindrical magnet is secured to the middle of the disc, and its upper end carries a flat disc pole piece whose outer rim is the inner side of the air gap. <IMAGE> |
