| 摘要 |
PURPOSE:To make rising steep at a high S/N ratio, by a method wherein two MR elements among four ones becoming a detection part approach each other and the remaining ones are allowed to be spaced apart from the previous MR elements by the length of the magnetized region of a magnet. CONSTITUTION:A magnetized region 7 having a predetermined length P is provided to a part of a strip like plastic magnet 5 and MR elements 1-4 constituting a detection part are arranged in opposed relation to the magnet 5 and the MR elements 1-4 are arranged along the magnet 5 in parallel to each other. The elements 1, 2 are arranged in close vicinity to each other and the element 3 is arranged so as to be spaced apart from the element 2 by the length P of the region 7 on the side opposite to the element 1. When the magnet 5 moves in the direction shown by an arrow, the magnetic field from the region 7 is detected as the change in a resistance value in the order of the elements 4, 1, 2, 3. Since the elements 1, 2 approach each other, detection outputs are an almost same phase and become twice. The detection outputs of the elements 3, 4 are delayed or advanced by the time required in passing through the region 7 over the length P thereof.
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