Each sensor of a linear array of sensors includes, in part, a sensing electrode and an associated feedback circuit. The sensing electrodes are adapted to be brought in proximity to a flat panel having formed thereon a multitude of pixel electrodes in order to capacitively measure the voltage of the pixel electrodes. Each feedback circuit is adapted to actively drive its associated electrode via a feedback signal so as to maintain the voltage of its associated electrode at a substantially fixed bias. Each feedback circuit may include an amplifier having a first input terminal coupled to the sensing electrode and a second input terminal coupled to receive a biasing voltage. The output signal of the amplification circuit is used to generate the feedback signal that actively drives the sensing electrode. The biasing voltage may be the ground potential.