At least one exemplary embodiment of the present invention includes a capacitive sensing system, comprising a sensing conductor coupleable to a grounded target by a gap capacitance C.sub.d, said grounded target separated from said sensing conductor by a gap having a width. The capacitive sensing system also comprises a circuit connected to said sensing conductor, an input signal having an input frequency f.sub.osc provided to said circuit through an input resistance R.sub.d, an output signal of said circuit having an output voltage varying linearly with the width of the gap when the impedance of the gap capacitance 1/(2.pi.f.sub.oscC.sub.d) approaches or exceeds the input resistance R.sub.d.
