| 摘要 |
<p>RCA 72,078 A playback system for recovering prerecorded information from a disc record through the use of a stylus mounted on a stylus arm includes a stylus arm liftinglowering device. The lifting-lowering device uses a permanent magnet mounted on a leaf spring. The permanent magnet is arranged to normally occupy the central volume of a core with a coil wrapped around the core. The leaf spring has an extension to receive the stylus arm. When an appropriate control signal is applied to the coil, a magnetic field is generated which tends to repel the magnet out of the central volume and the stylus arm, which rests on the extension, is gently lowered toward the record.</p> |
