Abstract: A circuit arrangement for determining a capacitance of a capacitive sensor element (C1) includes a square-wave voltage source (10) which is designed to output a square-wave voltage (UR) at an output connection (11), a sensor branch via which the square-wave voltage is applied to the sensor element, and an amplifier branch including a negative feedback resistor (R1), a transistor (T1) and an evaluation capacitor (C2), the negative feedback resistor, the transistor and the evaluation capacitor being looped-in in series between the output connection of the square-wave voltage source and a reference potential (GND), and a voltage (UOUT), which is a measure of the capacitance of the sensor element, being applied to the evaluation capacitor.

Abstract: A circuit arrangement for determining a capacitance of a capacitive sensor element (C1) comprises a square-wave voltage source (10) which is designed to output a square-wave voltage (UR) at an output connection (11), a sensor branch via which the square-wave voltage is applied to the sensor element, and an amplifier branch comprising a negative feedback resistor (R1), a transistor (T1) and an evaluation capacitor (C2), the negative feedback resistor, the transistor and the evaluation capacitor being looped-in in series between the output connection of the square-wave voltage source and a reference potential (GND), and a voltage (UOUT), which is a measure of the capacitance of the sensor element, being applied to the evaluation capacitor.