| 摘要 |
<p>PURPOSE:To effectively operate a dielectric detector when a dielectric to be detected is present, CONSTITUTION:A dielectric detector has a detector IC1 having switching means for detecting a change of an electrostatic capacity of a capacitor Cx to repeat charging and discharging of the capacitor Cx to oscillator a pulse signal, and a deciding circuit IC2 for judging presence of a dielectric based on an output of the detector IC1, and outputs end of periods of voltage signals output from the detector IC1 according to a frequency divider FC of detecting timing generating means for generating a signal for indicating a time point of charging and discharging, logic circuits AND, OR, NOT and SRFF. A threshold value VTH3 is decided via resistors R8, R9 of noise deciding means, a voltage signal is compared with the value VTH3 by a comparator CMP3, and its result is decided by the circuit IC2 to detect presence or absence of noise.</p> |
