JPS6444815A - Detecting element of origin of magnetic head for magnetic encoder - Google Patents

Abstract

PURPOSE:To obtain a detecting element whose pulse width is unvaried even when the relative directions of movement of a scale and a magnetic head are varied to be normal and reverse mutually, whose amplification rate is low and whose high-speed responsiveness is excellent, by a method wherein two series circuits arranged in parallel are formed of four blocks each comprising magnetoresistance elements in the number of (n) [(n) is a plus integer]. CONSTITUTION:Blocks B1-B4 each comprising magnetoresistance elements in the number of (n) are disposed in parallel sequentially. The blocks B1 and B3, and B2 and B4, are connected together respectively to form first and second series circuits respectively, and the two circuits are connected in parallel to form a bridge circuit. A supply voltage is impressed on the opposite ends of the two circuits, and first and second output signals are taken from the respective connection elements L1 and L3 of the first and second series circuits. A voltage difference between these two signals is amplified 2 and converted 3 into a rectangular one, and thus an origin signal of a rectangular wave is obtained at an output terminal 4. The pulse width of this signal is unvaried even when the direction of an origin position detection pattern 1a turns reverse.