Electronic capacitance level with automatic electrode selection

Abstract

A capacitive type, multi-electrode inclination sensor device utilizes a conductive fluid acting as a common capacitive electrode contained within a cylindrical cavity. Two or more coplanar sensor electrodes are covered by a thin dielectric film and are mounted on an end wall of the cavity. Each insulated electrode forms one plate of a capacitive element with the conductive fluid forming the other plate. The geometry of the sensor electrodes is such that for a given physical position of the device (such as level or plumb), equal conductive fluid coverage of a given pair of sensor electrodes occurs, yielding two identical value capacitances. Any inclination of the device within the plane of the capacitive plates then increases one capacitance's value while decreasing the other, with the differential change in capacitance being proportional to the angle of inclination.