Copper-Mandrel Potentiometer Dynamic Error and Compensation

A simple potentiometer equivalent circuit is presented that is valid for single or multiturn, copper-mandrel, wire-wound precision potentiometers. Developed to obtain a practical approximation of potentiometer ac characteristics, it is particularly useful in error analyses where small phase errors are critical. Capacitive compensation techniques are also given that can achieve considerable reduction in potentiometer dynamic error. Even for heavy capacitive loading it is possible virtually to eliminate potentiometer phase error (important in most analog computer circuits). Correspondingly, high-frequency square waves can be attenuated reasonably by such capacitively-compensated potentiometers.