Abstract: A set reset flip-flop having set and reset inputs to which input signals are applied. The flip-flop is selectively powered, its output condition being determined by the difference in the two input signals when it is being powered and driven through a linear region of operation.

Abstract: A proximity sensor system includes first and second circuits connected at their inputs to a source of sampling pulses and at their outputs to a difference circuit. A proximity sensor is connected to the first circuit for modifying the amplitude of the signals produced at its output in response to the presence of an object in proximity to the sensor. The signals produced at the output of the second circuit are substantially independent of the presence of an object. The difference circuit produces an output signal indicative of which one of the first and second circuits produces the largest amplitude signal and is indicative of the presence or absence of an object. The proximity sensor may be comprised of a sheet or conductive material with a first wire connected between the sheet and the first circuit and a second wire isolated from the sheet but extending along the first wire and being connected to the second circuit.