SIGNAL PROCESSING CIRCUIT FOR SENSOR UTILIZING CHANGE IN CAPACITANCE

摘要

PURPOSE:To obtain a signal processing circuit for sensor utilizing the change in capacitance which can output an accurate detection value without being affected by temperature. CONSTITUTION:A capacity element C is constituted of a pair of electrodes which are laid out so that the distance between them changes according to operation of external force and the external force is detected by change in capacitance of the capacity element C. One of rectangular waveforms which are fed to an input terminal T1 passes through an inverter element 71 and is fed to an EX-OR element 74 and the other passes through an inverter element 72 and then is fed to the EX-OR element 74 via a CR delay circuit which is constituted of the capacity element C and a resistance element 73. The EX-OR element 74 outputs the phase difference of both signals to an output terminal 72.