32.5.1.2 Mutual Capacitance Sensor Arrangement

A mutual capacitance sensor is formed between two I/O lines - an X-electrode for transmitting and a Y-electrode for sensing. The mutual capacitance between the X- and Y-electrodes is measured by the PTC.

A mutual capacitance sensor array is a good way to reduce the number of I/O lines needed to connect a large number of sensors. It is constructed by connecting the capacitor plates either horizontally or vertically, where horizontal and vertical lines do not physically connect, forming a mutual-capacitive sensor at each intersection.