Abstract: To provide a pressure sensor with good reproducibility, a cavern of elliptical outline is etched into a highly conductive monocrystalline n.sup.+ doped silicon chip, leaving a thin membrane of an epitaxial layer of elliptical outline, in which the ratio of the elliptical axes is about 2:1 and the elliptical axes extend at an angle of 45.degree. with respect to the (100) and (010) crystal axes; a resistance bridge, which may be formed by boron diffusion or ion implantation, or by transistor integrated circuit technology, is applied to the center of the membrane, having its resistance or transistor, for example FET transistor, branches arranged at the 45.degree. angle with respect to said crystal axes.