Abstract: A position indicator for producing a variable maximum, variable resistance for supplying a variable amplitude signal to a computer indicating the degree of displacement of a controlled element along an axis includes a variable resistance resistor; a variable displacement element coupled to the variable resistor for varying the resistance of the variable resistor according to displacement of the element along an axis; a first fixed resistance resistor connected to first and second terminals of a transistor, the transistor being connected in series with the variable resistor to form a first series circuit; a second fixed resistance resistor, a potentiometer having a fixed resistance and a variable position contact, and a third fixed resistance resistor connected in series as a second series circuit that is connected in parallel to the first series circuit; and an amplifier having a first inverting input terminal and a second non-inverting input terminal connected to the variable resistor and the variable positi