PRESSURE SWITCH CONTROL SYSTEM BY SEMICONDUCTIVE STRESS-SENSITIVE RESISTOR TYPE PRESSURE SENSOR

摘要

PURPOSE:To obtain a pressure switch by a semiconductive stress-sensitive resistor type pressure sensor reduced in the variation in sensitivity due to temp., by setting the zero point of bridge output voltage to a plus side at ambient temp. or more and to a minus side at ambient temp. or less. CONSTITUTION:This bridge consists of semiconductive stress-sensitive resistors 11, 12, 13, 14 and the zero point of bridge output voltage is set to a plus side at ambinet temp. or more with respect to an ambient level value and to a minus side at ambient temp. or less. The variation in bridge output voltage due to temp. can be reduced in the vicinity of applied pressure Pw by said setting. The setting of bridge output voltage may be performed by imparting a metal resistor to each resistor in parallel or in series and the adjustment thereof can be performed easily while bridge output voltage is observed. When the bridge output voltage to operation setting pressure Pw at ambient temp. is set to Uw and bridge output voltages at room temp., 100 deg.C and -20 deg.C are set tu U20, U100, U-20 at applied pressure P=0, it is desirable that U100 and U-20 are set to U20+Uw/30