Abstract: The pressure transducer includes a semiconductor cantilever beam, a diaphragm, a spacer, and a back plate. The diaphragm, spacer, and back plate are bonded together at their peripheries to form a cup. The ends of the beam are bonded, respectively, to the supported periphery of the diaphragm and to an intermediate deflecting portion thereof, whereby pressure forces within the cup are transmitted by the diaphragm to the beam. Piezoresistive elements are diffused into the surface of the beam to produce an electric signal in accordance with the strain produced in the beam as the result of the pressure forces. In one embodiment, the beam is a flat plate. In another embodiment, the beam includes a portion at the mounting end that is massive relative to the stress sensitive portion of the beam. The juncture of the massive mounting portion and the stress sensitive portion is an abrupt step, whereby a precise fulcrum for the stress sensitive beam portion is provided.

Abstract: A differential pressure to electrical signal transmitter has a pair of barrier diaphragms and one or two central control diaphragms located between the barrier diaphragms. A chamber on the outside of one barrier diaphragm is pressurized with a first fluid, and a chamber on the outside of the other barrier diaphragm is pressurized with a second fluid. First chambers between one of the barrier diaphragms and the control diaphragm, and a first length of capillary tubing connected between the first chambers and one chamber of a remotely located sensor capsule, are filled with a first incompressible fill liquid. Second chambers between the other barrier diaphragm and the control diaphragm, and a second length of capillary tubing connected between the second chambers and another chamber of the sensor capsule, are filled with a second incompressible fill liquid.