DIELECTRIC DETECTING DEVICE

摘要

PURPOSE:To eliminate the erroneous confirmation of 'presence of person' and 'absence of person' and detect a failure in a circuit by comparing the absolute value of the difference between the electrostatic capacity data when a switch is in OFF state and an initial set value with a standard value. CONSTITUTION:A detecting circuit IC1 is formed of a gate array to detect a change in the electrostatic capacity of a capacitor CA and control the start and stop of a judging circuit IC2. The judging circuit IC2 has a microcomputer to judge the presence of a person on the basis of the output of the detecting circuit IC1. The judging circuit IC2 stores the electrostatic capacity data when a switch SW1 is in OFF state as an initial set value. Thus, since a failure such as the release of an input signal detecting low pass filter FL1 is judged, for example, when the circuit characteristic of the detecting circuit IC1 is largely changed when the absolute value of the difference between the electrostatic capacity data when the switch SW1 is in OFF state and the initial set value is a first standard value or more and less than a second standard value, the presence of the person is never erroneously confirmed.