1 ) A capacitive sensor for providing an output representative of a position along a sensing body extending between two electrodes at which an object is proximate the sensing body, the sensor comprising: two capacitive sensing channels, each channel connected to a respective one of the electrodes, each channel having a respective channel output representative of a respective non-linear response to a capacitive load imposed by the object when the object is proximate the body; means for operating the two channels synchronously, and calculation means for receiving the respective outputs from the two channels, for calculating a ratio of a selected linear combination of the outputs of the two channels, the ratio varying linearly with the position of the object, and for supplying the ratio as the output representative of the position.