A free field stress gauge capable of dynamic and static response in the kbar (nominally 15,000 p.s.i.) range is disclosed. A first embodiment of the stress gauge of this invention comprises two circular plates, one of which is concentrically grooved. The other plate of the two circular plates serves as a cover plate. Strain gauge sensors are mounted on the inner ring or tube of the concentrically grooved plate. These sensors measure strains of the inner ring or tube induced by and proportional to stresses applied to the flat faces of the gauge. The second embodiment which operates in the same manner as the first embodiment is a solid column type of stress gauge.

A pressure transducer having means for improving the linearity and sensitivity of an output signal from the pressure transducer. Ribs and bosses are introduced in the diaphragm region to collect the moments caused by a difference in pressure on the two sides of the diaphragm and thus improve device sensitivity. In addition, the ribs and bosses prevent stretching of the piezoresistors thus improving the linearity of the device. A constraint can also be included to improve the alignment of the piezoresistors thus improving the linearity of the device.

This force transducer is intended for use in locations where the space available is dimensionally limited in the direction of the active and reactive forces being measured. It is more resistive to forces acting at an angle with respect to those active and reactive forces than the devices of the prior art. It comprises a cylindrical block, usually steel, having a central load bearing portion adapted at one end to oppose a force acting axially of the block, and a peripheral portion concentric with the central portion and adapted at the opposite end to oppose the reactive force. The central portion and the peripheral portion are separated by two arrays of cylindrical holes, with at least three holes in each array, each hole extending parallel to the axis of the block and spaced therefrom. The two arrays of holes define at least three pairs of parallel bridging portions extending between the central load bearing portion and the peripheral load bearing portion. Two strain sensitive elements are mounted on each bridging portion on opposite surfaces thereof, so that two strain sensitive elements are located inside each hole. The strain sensitive elements are connected in a bridge circuit. Two span temperature compensating resistance elements are located in two of the holes, and are connected in series with the bridge circuit.

A measurement transformer has a pressure chamber which is sealed off by a membrane (2). On the membrane (2) there is seated a ram (16) which rests against a central part (7) of a spring plate (6). The central part (7) is connected by means of two flexural beam sections (9, 10) with the edge of the spring plate (6). Furthermore, web sections (13, 14, 15) connect the central part (7) to the edge part (8). For the adjustment of the measurement transformer the web sections (13, 14, 15) can be cut through. The more web sections (13, 14, 15) are cut through, the easier it is for the central part (7) to be displaced relative to the edge part (8). Wire strain gauges (11, 12) on the beam sections (9, 10) register this displacement.

A differential pressure measuring transducer assembly of semiconductor material including a pressure receiving section producing a displacement when pressure is applied, and a stationary section of large thickness located at an outer periphery of the pressure receiving section. The pressure receiving section is composed of a large thickness portion extending to the stationary section at the outer periphery, and a small thickness portion occupying the rest of the pressure receiving section, and a gauge resistance is provided to the large thickness portion.