| 摘要 |
PURPOSE:To equalize the earth potential of a control circuit to the earth potential of respective conversion parts and the converter and to perform invariably accurate pressure detection irrelevantly to variation in the earth potential by leading the earth potential of the control circuit to a piezoelectric conversion part and a charge-voltage converter. CONSTITUTION:The cylinder body 20 of the pressure sensor S consisting of the cylinder body 20, a spacer 30, and a sensor main body 40 is formed of a metallic material in a U-section shape, the sensor main body 40 is supported coaxially with the conductive holding member 10 for an opening part 21, and pressure is converted into a charge quantity. Further, the charge-voltage converter 70 is joined with the rear part of the sensor main body 40 through an insulating plate 41 and a support member 42a. This converter 70 converts the charge quantity obtained by the sensor main body 40 into a voltage, which is applied to a control circuit 130 by a connection lead wire 120. Then, the earth potential at the earth terminal 133 of the circuit 130 is led to the closed curve (p) formed of the sensor main body 40 and converter 70 by a lead wire 120 to equalize the earth potential of the circuit 130 to the earth potential of the closed curve (p).
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