Abstract: A capacitive fill level sensor for measuring the fill level of a medium in a container has an electrode unit, which contains a strip-shaped measurement electrode, a strip-shaped counter electrode and a strip-shaped shielding electrode, the shielding electrode at least partially surrounding the measurement electrode. A first AC voltage source having a predefined frequency and amplitude is provided, to which the shielding electrode is connected such that a shielding capacitor formed between the shielding electrode and the measurement electrode has a shielding capacitance that is proportional to the length of the shielding electrode.

Abstract: A capacitive fill level sensor for measuring the fill level of a medium in a container has an electrode unit, which contains a strip-shaped measurement electrode, a strip-shaped counter electrode and a strip-shaped shielding electrode, the shielding electrode at least partially surrounding the measurement electrode. A first AC voltage source having a predefined frequency and amplitude is provided, to which the shielding electrode is connected such that a shielding capacitor formed between the shielding electrode and the measurement electrode has a shielding capacitance that is proportional to the length of the shielding electrode.

Abstract: The invention proposes a circuit arrangement for determination of a measuring capacitance (1), comprising a reference circuit portion for defined periodic charging and discharging of a predefined reference capacitance (1a), and a measuring circuit portion for defined periodic charging and discharging of the measuring capacitance (1) to be determined, and at least one circuit portion (4, 7; 4a, 7a) intended to determine at least one value (M2) characteristic of the charging time curve of the reference capacitance (1a) and for deriving at least one value (M1) characteristic of the charging time curve of the measuring capacitance (1), as well as a circuit portion (9) for comparing the at least one value (M2) characteristic of the charging time curve of the reference capacitance (1a) with the at least one value (M1) characteristic of the charging time curve of the measuring capacitance (1), and for deriving from that comparison the value of the measuring capacitance (1).

Abstract: The invention relates to a sensor for the contactless detection of the level of a liquid and adhering high-conductivity medium, especially blood, through a non-metal container wall. The sensor has a pulse generator (1) that generates brief pulses which, via a low-ohm resistor (2), namely, the measuring resistor, actuate an electrode (4) installed on the outside of the container wall.

Abstract: The invention proposes a circuit arrangement for determination of a measuring capacitance (1), comprising a reference circuit portion for defined periodic charging and discharging of a predefined reference capacitance (1a), and a measuring circuit portion for defined periodic charging and discharging of the measuring capacitance (1) to be determined, and at least one circuit portion (4, 7; 4a, 7a) intended to determine at least one value (M2) characteristic of the charging time curve of the reference capacitance (1a) and for deriving at least one value (M1) characteristic of the charging time curve of the measuring capacitance (1), as well as a circuit portion (9) for comparing the at least one value (M2) characteristic of the charging time curve of the reference capacitance (1 a) with the at least one value (M1) characteristic of the charging time curve of the measuring capacitance (1), and for deriving from that comparison the value of the measuring capacitance (1).

Abstract: The invention relates to a sensor for the contactless detection of the level of a liquid and adhering high-conductivity medium, especially blood, through a non-metal container wall. The sensor has a pulse generator (1) that generates brief pulses which, via a low-ohm resistor (2), namely, the measuring resistor, actuate an electrode (4) installed on the outside of the container wall.

Abstract: A sensor according to the invention has an amplifier that is capacitively loaded vis-à-vis the ground by a container and by a medium contained therein and that has a capacitive feedback that is dimensioned in such a way that the amplifier only oscillates when the critical filling level has not been reached. According to the invention, the capacitive feedback is influenced by the container in such a way that the capacitive load of the amplifier input caused only by the container is countered. In this manner, it is achieved that the sensor responds only to the capacitance of the medium, largely independently of the magnitude of the container capacitance.