<div class="htmlview paragraph">Current worldwide development activity and potential markets for magnetostrictive, noncontact, torque sensors are reviewed first. Then, a general model for the sensor is derived, and equivalent electrical and magnetic circuits for the sensor are developed. The model is defined in terms of a basic single-branch magnetostrictive sensor element, combinations of which serve as models for multi-branch sensors.</div> <div class="htmlview paragraph">Key assumptions are made that permit simplification of model equations. Procedures for reliable evaluation of magnetic permeance parameters (essential for insuring accuracy of the model) are also given.</div> <div class="htmlview paragraph">Physical origins of the sensor output signal are described, and discussion of characteristic behavior of magnetostrictive sensing-member materials are given. It is shown that all practical sensors include some means of compensation to average out characteristic nonideal properties of magnetostrictive sensing materials.</div>