Variable Radius Helix Potentiometer: Practical Issues

Abstract

Recently a new approach to constructing potentiometers with non-linear taper was proposed. Its main idea is to reach a non-linear dependence of output voltage on rotation angle using a helical resistive element with variable radius of the helix and cross-section. As it has been shown before, problem of calculation of such potentiometer has a solution for all continually differentiable tapers, but the usefulness of this construction is still unknown. In the current paper we review historical and modern types of potentiometers, including non-linear ones; materials for manufacturing such pots; possible tapers for this type of construction; potential applications. In section 1 potentiometer constructions and materials are analyzed. Most suitable constructions for implementation of variable-radius-helix approach are chosen. A generic way for manufacturing mandrel and resistive element using modern machining tools with computer numeric control. In section 2 tapers for potentiometers with several predefined mandrel shapes are calculated. A comparison between appropriate taper bounds for VRH potentiometer and a conventional multi-turn with variable wirewound pitch is carried out. In section 3 different fields of potentiometer applications are reviewed, including usage of potentiometer in new works on robotics. VHR potentiometer is proposed for use in a manual control system for vehicle cab heating controllinstead of a potentiometer with piecewise-linear taper. In section 4 conclusions are made on perspectives of this type of potentiometer, its pros and cons. Main tasks for further research are outlined.