| 摘要 |
PURPOSE:To detect highly precise rotation extending over a wide temperature range by outputting a rotation detection signal having the fixed pulse width without being influenced by a change of the outside air temperature. CONSTITUTION:A threshold setting circuit 10 is constituted by connecting resistances R1 and R2, and a thermistor Th1 in series and the set voltage VT10 is outputted from between the resistance R1 and R2. On the other hand, a thresh old setting circuit 11 is constituted by connecting resistance R3, a thermistor Th2 and resistance R4 in series and the set voltage VT11 is outputted from between the thermistor Th2 and the resistance R4. The set voltage VT10(VT11) by the circuit 10(11) is made a characteristic approximate to the characteristic of a D.C. voltage level Vout4DC(5DC) by a detection part 4(5). Accordingly, the output voltage Vout4(5) is made low (high) at the time of the high temperature with respect to at the time of the low temperature or at the time of the normal temperature with the detection part 4(5). Then, when the level Vout4DC(5DC) of the detection part 4(5) and the set voltage VT10(VT11) of the circuit 10(11) are supplied to a comparison circuit 14(15), a variation of the pulse width by the output voltage is remarkably reduced.
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