| 摘要 |
PURPOSE:To prevent magnetic interference among magnetic zones and accurately detect a crank-angular position by making a rotational angle sensor wherein nonmagnetic zones are formed between a plurality of rows of magnetic zones. CONSTITUTION:The magnetic field of the magnetic zones 46, 48 and 50 of a magnet ring is applied to three Hall elements 40 provided on a sensor substrate close to body of rotation 16 that is rotated at half the number of revolutions of the crank shaft (not shown) of an internal combustion engine to produce an electromotive force. The output of the three Hall elements 40 is taken out from output terminals 72, 74 and 76 via a DC component removing circuit 66 provided with a differential amplifier 60 and a comparator circuit 70 provided with a comparator 68 to be fed to the processing circuit (not shown) of a subsequent stage. Since first and second nonmagnetic zones 54 and 56 are provided between the magnetic zones 46 and 48 and between 48 and 50, respectively, the magnetic zones 46, 48 and 50 are prevented from receiving magnetic interference with one another.
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