Magnetostrictive stress sensor

A magnetostrictive stress sensor is provided with a soft-ferromagnetic body having a grain structure, at least a part of the grains having a grain size in the transition region between the one-domain and the two-domain state. At this grain size, which is of the order of 1 to 9 mu m for a ferrite body, a relatively large magnetostrictive effect occurs. In a practical embodiment, the ferromagnetic body is formed by a ferrite core, in particular a ferrite ring, around at least a part of which an electric coil is wound, which is incorporated in a measuring circuit for measuring changes in the self-induction of the coil under the influence of mechanical pressure exerted on the ferrite core