Abstract: A circuit and method is disclosed which determines the physical position of a selected resistance setting of a mechanical variable resistive component, such as a potentiometer, between its mechanical limits as a ratio of its selected resistance and its total resistance. The circuit includes a potentiometer, a capacitor and a microprocessor, which form a charging circuit. The microprocessor has three I/O pins, which are connected to the three terminals of the pot. The capacitor is connected in series to the pot, so that it can be charged by a voltage signal from the microprocessor either across the selected resistance of the pot's wiper or across the entire resistance of the pot. The microprocessor executes a program, which embodies the method of this invention.