| 摘要 |
PURPOSE:To secure a pressure sensing circuit for use in a power wind device with ability of stable and accurate sensing of pressure, and enhance the reliance upon the foreign matter pinch sensing. CONSTITUTION:No.1 amplifier 1 has a pressure sensor 2, which is connected between an inversive input terminal 1a and an output terminal and whose resistance value Rs varies in compliance with the pressur force P, wherein the inversive input terminal 1a is grounded through a grounding resistance 3, and the output terminal is connected to an output terminal 5 and No.2 amplifier 6 inversive input terminal. To the non-inversive input terminal of this amplifier 6, a reference voltage source 7 is connected. This source 7 generates a constant reference voltage Eref, and output end 6c is connected to No.1 amplifier 1 non-inversive input terminal through a time constant circuit 8. This time constant circuit 8 is composed of a resistance 9, which is connected in interposition between the amplifier 6 output terminal and the amplifier 1 non-inversive input terminal, and a grounding capacitor 10 in connection with the amplifier 1 non- inversive input terminal. |
