Abstract: Use is made of thermoplastic materials in layered configurations as a thermally stable, rigid but not brittle strip of lengths of six inches to ten feet or more. The layered strip contains layers of conductive fibers in a resin matrix, which, through use of appropriate contact mechanisms and wiring, provide an assembly with an infinite potentiometer scale. The strips are especially useful in linear positioning indicators such as pneumatic and hydraulic cylinder and liquid level gauges.

Abstract: A miniature potentiometer suitable for mechanical adjustment of microwave circuits is provided. Furthermore, there is provided a dual, ganged potentiometer also suitable for mechanical adjustment of microwave circuits. The dual, ganged potentiometer provides reliable tracking of tapers between the two variable resistance elements. Yet further, there is provided a complete, microwave, T-pad attenuator circuit which is mechanically adjustable. The T-pad attenuator uses two ganged potentiometers, whose tapers track in a known non-linear fashion. The tapers may be logarithmic.

Abstract: A liquid level sensor for sensing liquid levels within a container is disclosed. The sensor includes a conductive plastic resistor and conductive plastic conductors deposited onto a thin polymer insulator. The conductive plastic resistor is a potentiometric resistive track which is electrically contacted at points along the length of the resistor by a contact assembly attached to a float. The polymer insulator is attached to a conductive support member or conductive strip disposed substantially vertically in the liquid. The float is disposed about the conductive strip. The contacts provide a short circuit between the resistive strip and conductive strip and thereby provide a resistive circuit connection analogous to the wiper of a potentiometer.

Abstract: Variable resistor comprises a lead screw 12 rotatably mounted to substrate 42 by conductive mounts 18, 18' and engaging a one-piece stamped and formed sheet metal slider 16 movable along circuit trace 20 in response to rotation of the screw 12. The lead screw 12 is a conductive plastic and thus acts as a resistance element, the resistance between the mounts 18, 18' and the circuit trace 20 being varied by rotating the screw 12. Mounts 18, 18' have spring-loaded arms 34, 36 which releasably retain the lead screw 12 so it may be replaced if it is desired to change the resistance limits of the device.