Abstract: A fluid pressure transducer comprises a chamber; one or more matched, plate-like crystals within the chamber; electrical means for exciting each of the crystals and means for transmitting forces originating from fluid pressures on two diaphragms located on the chamber to the crystal or crystals so as to produce a change in the resonant frequency of the crystal or crystals. This change is a measure of the difference in fluid pressures applied to the two diaphragms. SPThis application is a continuation-in-part of my copending application Ser. No. 499,489 filed Oct. 22, 1974, now U.S. Pat. No. 4,020,448 issued Apr. 26, 1977. The specification and drawings of that prior application are hereby incorporated into this application by reference.

Abstract: A force transducer comprises a chamber; two matched plate-like crystals mounted facing each other within the chamber upright with respect to a base member provided within the chamber; electrical means for exciting each of the crystals; and means for transmitting a force to one of the crystals, including a spigot assembly which is mounted within the chamber by means of two spaced apart resilient supports and arranged to bear on one edge of said one crystal so as to produce in response to said force a change of the resonant frequency of that crystal with respect to the other crystal.