| 摘要 |
A circuit for detecting the presence, position or the approach of an object in an observation area, the circuit has a sensor electrode assembly with an electrode that forms part of a capacitor system whose capacitance relative to a reference potential (e.g. ground) is dependent on the presence, position or approach of objects in the observation area. An evaluation circuit coupled to the sensor electrode detects a phase shift of the capacitance of the condenser system. An LC network is coupled to the capacitor system, and an oscillator connected to the electrode applies a frequency to the system formed by including the electrode and the LC network at a frequency within the range of a parallel resonance frequency of the LC network.
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