A displacement detector especially intended for a gear wheel grinding or inspecting machine contains a conventional pre-stage comprising a forward-backward counter receiving measuring pulses, a buffer or intermediate store for preserving the counter state at each moment, and a comparator for detecting predetermined position values during a measuring operation. To prevent overflow of the counter during more extended travel paths and at high resolution a pulse storing and detecting circuit and a synchronizer circuit are provided which enable the counter to be reset at any moment without any pulse becoming lost. Consequently, a conventional 8-bit or 16-bit microprocessor system and circuit components or elements of the same bit format can be used. The use of a 32-bit format is thus avoided, which otherwise requires substantially higher expense in terms of hardware, space and circuitry and which otherwise unavoidably must be used for more extended travel paths and high resolution.