| 摘要 |
<p>The magnetic sensor (10) having primary winding (14) fed with AC current and at least two secondary windings (16,18) connected to a differential sensing circuit, which produces amplitude modulated electrical signals which represent variations in the magnetic field due to the presence of a target (12). The target (12) present at least two successive zones alternatively made from a first conducting material and a second ferromagnetic material. The frequency of the alternating supply current is chosen so that the signals produced by the secondary windings are the maximums for the first and second materials. The target (12) presents a regular succession of alternate zones made from a first conducting material and a second ferromagnetic material. The distance between adjacent zones of different material is equal to the useful diameter of the secondary windings. The target is made from a substrate, conductor or ferromagnetic material, and the zones in the other material are placed on the substrate.</p> |
