摘要 |
A sensing device with improved sensitivity for sensing the velocity of a rotating magnetizable wheel is disclosed. The sensing device utilizes two closed-loop magnetic cores and four inductive windings which are interconnected to form a four-arm active bridge circuit, all arms of which are affected by the rotating wheel. A permanent magnet biases the two magnetic cores to partial saturation and also supplies magnetic flux to the rotating wheel. In one version, two windings are wound around each of the cores. In another version, one winding is wound around each of the cores; and a separate magnetic member that provides a return path for the bias magnetic flux that passes through the cores has two apertures at its ends and each of the other two windings is wound through one of these apertures. |