| 摘要 |
PURPOSE:To detect the movement of a steel ball positively, to detect the instance of the movement accurately and to adjust the position of a permanent magnet positively by stopping the conduction of a highfrequency current to a primary coil, and preventing the reduction of the output voltage caused by the movement of the steel ball by the voltage caused by the high-frequency current. CONSTITUTION:A switch 12 is opened, and the conduction of a high-frequency current through a primary coil 3 is stopped beforehand. When a second permanent magnet is brought close to a tube part and moved, a steel ball 2 is moved to the side of the second permanent magnet. Voltages are outputted into a detecting circuit 13 from secondary coils 4 and 4. The circuit 13 outputs the detected signals into a driving circuit 14. The circuit 14 stops the driving current into a motor 15, and the second permanent magnet is stopped. The position of the second permanent magnet is adjusted with the position at this time as a reference. Therefore, the output voltages of the secondary coils 4 and 4 caused by the steel ball 2 are not affected with the output voltage caused by the high- frequency current. The movement of the steel ball 2 can be positively detected. |
