A variable capacitance transducer has a cable loop interlinked with a metallic tube. The cable loop comprises a metallic cablehalf joined to an insulative cable-half. The portion of the cable loop passing through the metallic tube is axially positioned in the tube and a capacitive element is formed by the metallic tube and the metallic cable-half. Displacement of the cable loop to vary the amount of the metallic cable-half inside the metallic tube varies the capacitance of the capacitive element in a linear manner.