Differential capacitance sensor diode circuit

摘要

A capacitance sensor assembly for use with a label detection and registration system for detecting a lateral edge of a label on a web bearing a plurality of such labels and moving in a longitudinal direction through a capacitance gap in the sensor assembly. The capacitance sensor assembly includes a reference plate electrode, and a pair of sensor electrodes extending substantially parallel to and spaced apart from the reference plate electrode to form the capacitance gap. The pair of sensor electrodes has a differential capacitance, when the web bearing the plurality of labels thereon is in the capacitance gap, which is used to provide a signal indicative of the lateral edge of the label.