Abstract: An apparatus includes a series connection of at least a first impedance and a second impedance, the first impedance having a first terminal and a second terminal and the second impedance having a first terminal and a second terminal. The second terminal of the first impedance is connected to the first terminal of the second impedance forming a first node. The apparatus further includes a signal generator to apply a first amplitude modulated signal to the first terminal of the first impedance and a second amplitude modulated signal to the second terminal of the second impedance; and further includes an evaluation device configured to receive a first measurement signal from the first node and to determine information on the at least one physical parameter depending on the first measurement signal.

Abstract: An apparatus includes a series connection of at least a first impedance and a second impedance, the first impedance having a first terminal and a second terminal and the second impedance having a first terminal and a second terminal. The second terminal of the first impedance is connected to the first terminal of the second impedance forming a first node. The apparatus further includes a signal generator to apply a first amplitude modulated signal to the first terminal of the first impedance and a second amplitude modulated signal to the second terminal of the second impedance; and further includes an evaluation device configured to receive a first measurement signal from the first node and to determine information on the at least one physical parameter depending on the first measurement signal.

Abstract: A sensor system for the capacitive detection of obstacles, having a capacitive sensor with conductive elements and a control circuit connected thereto. The control circuit has a bridge circuit, and a first end of the bridge branch is connected to a conductive element of the sensor positioned upstream in the direction of detection and a second end of the bridge branch is connected to a conductive element of the sensor positioned downstream in the direction of detection. A control signal is generated by a control section of the control circuit and the sum of impedances of the bridge circuit connected to the first end of the bridge branch is less than the sum of impedances of the bridge circuit connected to the second end of the bridge branch. An electronic evaluation unit is provided to evaluate a voltage difference between the first and second ends of the bridge branch.