Abstract: By applying to a linear, time-invariant process or system a pulse of predetermined duration instead of a step function and measuring the area enclosed by the pulse and the response curve of the process, respectively, instead of measuring the slope of a tangent line to the point of inflection of the response curve, the time constant or constants of a closed-loop (self-balancing) or open-loop (non-self-balancing) process may be accurately determined and from such time constant or constants the process may be optimally tuned according to one of the accepted tuning methods.