A resistor card for a potentiometer to measure the fuel in a fuel tank consists of a non-conductive substrate with a plurality of elongate conductive contacts deposited thereon. The contacts have an elevation above the surface of the substrate and the contacts are oriented in parallel relationship to each other to form a wiper track across which a wiper is moveable. To reduce the rate at which the upper surfaces of the contacts are worn away by movement of the wiper, an insulating or highly resistive filler material is deposited between the conductive materials which form the lands.