| 摘要 |
<P>PROBLEM TO BE SOLVED: To make functions stable without being affected by cable length and environment of place and usable free of maintenance. <P>SOLUTION: A detector comprises a detection electrode 20 made of a metal plate formed in a slab shape arranged in an object detection region, a charging system 30 having a direct current source 301, a discharging system 40 having a current detection means and a switch S1 alternatively switching the charging system 30 and the discharging system 40 at a specific turn-over frequency and detects capacitance Cs between an object to be detected H and the detection electrode 20 as a current Is flowing in the discharging system 40. <P>COPYRIGHT: (C)2003,JPO |
