Capacitive sensor for use in collision protection device for detecting body part of person getting jammed with e.g. window glass of motor car, has switching circuit whose receiver inputs are in parallel connection and alternatively operable

摘要

The sensor (2) has an electrode assembly (4) with a transmission electrode (5) and a receiving electrode (6), and a reception switching circuit (9) arranged downstream to the receiving electrode for processing a received signal (Se) produced in the receiving electrode. The switching circuit has high- and low impedance receiver inputs (11, 12) that are in parallel connection. The receiver inputs are operable alternative to each other, and respectively formed by a potential measurement circuit i.e. voltage follower, and a displacement current measurement circuit i.e. transimpedance amplifier.