Abstract: In the sensor: torsion beams 7a, 7b are fixedly connected between the centers of opposite outer sides of central fixed board 1 and the corresponding centers of opposite inner sides of a window 5; electrodes 11a, 11b, 12a, 12b are mounted on a front and a rear surface of weight portions 9a, 9b; and, an outer cover 21, which is constructed of an upper and a lower board 17, 19 provided with electrodes 23a, 23b, 25a, 25b corresponding to the electrodes of the weight portions, is mounted on a side surface of an outer frame 15 in which both the central fixed board 1 and the weight board 3 are received, so that the central fixed board 1 is rotatably supported. It is possible to increase the length of each of the torsion beams 7a, 7b. These electrodes 11a, 11b, 12a, 12b may be produced through a single path in printing process.

Abstract: In the sensor including a frame member provided with a central opening portion, a pair of beam members extending from adjacent corner portions of the frame member toward a center of the opening portion, and the beam members have vibrating-end portions, i.e., inner end portions, connected with each other through a weight portion. Each of the beam members is provided with a concave portion in cross section. A piezo-resistance device is formed on each of the beam members, respectively. The beam members are improved in mechanical strength without a corresponding increase in a thickness of each of the beam members, while the piezo-resistance devices formed on the beam members are improved in sensitivity to vibrations.

Abstract: An disclosed an acceleration sensor for detecting three accelerations includes acceleration in a direction of a Z axis and angular accelerations about X and Y axes. The sensor includes an inner support, a ring-shaped weight surrounding the inner support, and an outer support surrounding the weight, all disposed in a plane including the X and Y axes which are perpendicular to each other. The weight includes four objective parts for detection which are arranged in the above-mentioned plane. The objective parts are located in line symmetry with respect to the X and Y axes and arranged at intervals of 90.degree. about the center of gravity of the weight. The inner support and the weight are connected together by a thin and elastically deformable first bridge. The weight and the outer support are also connected together by a second bridge of a similar configuration. These bridges each include a ring portion, a pair of inner connecting portions and a pair of outer connecting portions.