Process for operating a capacitive switch and a circuit of a capacitive switch

摘要

A capacitive switch is presented including an oscillator, with a gauge length and an evaluation circuit. The oscillator delivers a measurement signal and the gauge length has at least one sensor with a sending electrode and a measurement electrode. The switch has a low noise emission and is especially invulnerable to incident noise due to the fact that there is a noise source and two correlators. In the first correlator, frequency-spreading of the measurement signal takes place. The frequency-spreading measurement signal is connected to the second input of the second correlator and to the sending electrode. The measurement electrode is connected to the first input of the second correlator.