Abstract: A method and apparatus for detecting the point of contact between a workpiece of electrically conductive material in a machine and an electrically conductive element movable relative to and insulated from the workpiece, such as the electrode of an electrical discharge machine, wherein in a time-varying signal, in particular sinusoidal, of predetermined amplitude and frequency is applied to the workpiece, a signal is derived from the conductive element or electrode resulting from the flow of current through the gap between the workpiece and conductive element in response to the applied signal, and the applied and derived signals are compared as to amplitude and phase angle. An indication of the comparison is provided with the result that the combination of an amplitude difference and a phase difference between the applied and derived signals indicates the status of the contact gap, respectively, between the workpiece and conductive element or electrode.