Abstract: The present disclosure provides a microphone, comprising a shell structure, a vibration pickup assembly, a vibration pickup assembly, wherein the vibration pickup assembly is accommodated in the shell structure and generates vibration in response to an external sound signal transmitted to the shell structure, and at least two acoustoelectric conversion elements configured to respectively receive the vibration of the vibration pickup assembly to generate an electrical signal, wherein the at least two acoustoelectric conversion elements have different frequency responses to the vibration of the vibration pickup assembly.

Abstract: This disclosure is related to devices, systems, and techniques for securing one or more mechanical structures to a frame of a proof mass assembly. For example, a system includes a light-emitting device configured to emit an optical signal, a circuit including a modulating device configured to modulate the optical signal to produce a modulated optical signal, and a mechanical assembly. The mechanical assembly includes an anchor structure including a set of connecting structures configured to pass the modulated optical signal, where the set of connecting structures includes two or more connecting structures, and where a width of each connecting structure of the set of connecting structures is less than a maximum width of the anchor structure and a mechanical structure intersecting with the anchor structure, the mechanical structure configured to guide the modulated optical signal.

Abstract: A pressure regulator includes a container defining a variable volume chamber having a least one first orifice to be connected to an auxiliary hose such that, in use, the variable volume chamber of the pressure regulator and a sealing cuff are in communication. The regulator includes a pressure means acting on the container for exerting a certain force by means of a weight that can move along an articulated rod for adjusting the air pressure contained in the variable volume chamber. A system for locking the weight is provided for preventing unexpected movement of the weight. The invention is applicable to endotracheal tubes, tracheotomy tube or similar instruments for the ventilation of a patient.

Abstract: A force detecting device includes a recess located on the outer surface of the force detecting device and an electric connector provided in the recess. An electric cable for the force detecting device attached to the electric connector is inserted into the through-hole.

Abstract: Embodiments of the invention include a sensing device that includes a base structure having a proof mass that is positioned in proximity to a cavity of an organic substrate, a piezoelectric material in contact with a first electrode of the base structure, and a second electrode in contact with the piezoelectric material. The proof mass deflects in response to application of an external force or acceleration and this deflection causes a stress in the piezoelectric material which generates a voltage differential between the first and second electrodes.

Abstract: A spectrum analyzer includes: a support substrate; and a plurality of resonators that have center frequencies different from each other, one end of each of the plurality of resonators being fixed to the support substrate. The plurality of resonators are arranged so that an interval between resonators having adjacent center frequencies is secured by a certain value or greater, thus reducing coupling and increasing analysis accuracy.

Abstract: The present disclosure discloses a piezoelectric sensor and a method for manufacturing the same to realize omni-directional pressure sensing. The piezoelectric sensor according to the present disclosure comprises a first electrode layer, a second electrode layer and a piezoelectric thin film layer between the first electrode layer and the second electrode layer, the piezoelectric sensor further comprising: a first functional module and a second functional module, both of which are connected to the second electrode layer, wherein the first functional module is configured to sense a pressure applied to the piezoelectric sensor in a first direction, and the second functional module is configured to sense a pressure applied to the piezoelectric sensor in a second direction, the first direction and the second direction are perpendicular to each other.

Abstract: A system comprising a housing, a printed circuit board and a differential pressure sensor located inside the housing, and first and second male adaptors. The first and second male adaptors respectively extend through first and second openings in the housing. The first male adaptor comprises a proximal end configured to receive a first pipe, a distal end secured to the differential pressure sensor, and an internal fluid conduit for transmitting fluid received from the first pipe to the differential pressure sensor. The second male adaptor comprises a proximal end configured to receive a second pipe, a distal end secured to the differential pressure sensor, and an internal fluid conduit for transmitting fluid received from the second pipe to the differential pressure sensor. The differential pressure sensor is configured to determine a pressure differential between fluid received via the first male connector and fluid received via the second male connector.

Abstract: According to one embodiment, a strain and pressure sensing device includes a semiconductor circuit unit and a sensing unit. The semiconductor circuit unit includes a semiconductor substrate and a transistor. The transistor is provided on a semiconductor substrate. The sensing unit is provided on the semiconductor circuit unit, and has space and non-space portions. The non-space portion is juxtaposed with the space portion. The sensing unit further includes a movable beam, a strain sensing element unit, and first and second buried interconnects. The movable beam has fixed and movable portions, and includes first and second interconnect layers. The fixed portion is fixed to the non-space portion. The movable portion is separated from the transistor and extends from the fixed portion into the space portion. The strain sensing element unit is fixed to the movable portion. The first and second buried interconnects are provided in the non-space portion.

Abstract: An asymmetric sensor having asymmetric electrodes and/or being asymmetrically anchored provides enhanced sensitivity. In example embodiments, part of the electrode on a sensor is etched or removed resulting in enhanced mass-change sensitive resonant modes. In another example embodiment, a sensor is anchored asymmetrically, also resulting in enhanced mass-change sensitive resonant modes. By asymmetrically anchoring a piezoelectric portion of a sensor, resonant bending modes of the sensor can be measured electrically without external instrumentation. Modifying the electrode of a piezoelectric cantilever enables expression of mass-change sensitive resonant modes that normally do not lend themselves to electrical measurement.

Abstract: A sensing device, a method for fabrication thereof, and a method for operating the same are disclosed. The sensing device includes a flexible substrate, a first metallization layer, a piezoelectric thin film layer, a second metallization layer, and an insulating layer. The first metallization layer forms at least a source region and at least a drain region. The piezoelectric thin film layer provides a channel region permitting passage of charge carriers between the source region and the drain region. The second metallization layer forms at least a gate electrode and regulates flow of charge carriers through the piezoelectric thin film layer. When subjected to an external force, the flow of charge carriers is modulated in response to a strain in the piezoelectric thin film layer. The force is measured as a correlation between the applied force and the modulation of the flow of charge carriers.

Abstract: A pressure sensor measures pressure by measuring the deflection of a MEMS membrane using a capacitive read-out method. There are two ways to implement the invention. One involves the use of an integrated Pirani sensor and the other involves the use of an integrated resonator, to function as a reference pressure sensor, for measuring an internal cavity pressure.

Abstract: A coriolis flow sensor is disclosed. The coriolis flow sensors comprises a first substrate layer, a second substrate layer, and a third substrate layer. The first substrate layer comprises a first wall. The second substrate layer comprises a second wall. The third substrate layer is disposed between the first and second substrate layers in a stacked configuration. The third substrate layer defines a flow path. The first and second walls of the respective first and second substrates and the flow path defined by the third substrate layer define a first flow channel configured to receive a fluid therethrough. A first actuator is configured to generate vibrations in the first flow channel. The first flow channel is mechanically moveable.

Abstract: A resonant transducer includes a silicon single crystal substrate, a silicon single crystal resonator disposed over the silicon single crystal substrate, a shell made of silicon, surrounding the resonator with a gap, and forming a chamber together with the silicon single crystal substrate, an exciting module configured to excite the resonator, a vibration detecting module configured to detect vibration of the resonator, a first layer disposed over the chamber, the first layer having a through-hole, a second layer disposed over the first layer, a third layer covering the first layer and the second layer, and a projection extending from the second layer toward the resonator, the projection being spatially separated from the resonator, the projection being separated from the first layer by a first gap, the second layer being separated from the first layer by a second gap, the first gap is communicated with the second gap.

Abstract: A method for measuring pore pressure is provided using a rigid piezometer that does not need a filter and can be used to measure pore-water pressures in partially frozen soils. This method also can be used to measure pore pressure in a porous media when the hydraulic conductivity of the porous media is low or there is limited amount of pore-fluid available to transfer the pressures. A piezometer is also provided, including: a tube for hydraulic fluid; first and second valves to control fluid flow in the tube and into a porous medium; and a fitting wherein a pressure sensor is positioned to measure fluid pressure in the hydraulic fluid in the tube and a hydraulic fluid droplet ejected from an end of the tube into the porous medium; and an interface of the hydraulic fluid with the pore-fluid within the porous medium, using the droplet placed into the porous medium. The tube (or part of the tube), valves, fittings, and pressure sensor may be enclosed in a housing.

Abstract: Micro pick up arrays for transferring micro devices from a carrier substrate are disclosed. In an embodiment, a micro pick up array includes a compliant contact for delivering an operating voltage from a voltage source to an array of electrostatic transfer heads. In an embodiment, the compliant contact is moveable relative to a base substrate of the micro pick up array.

Abstract: A system for wearable/man-portable electromagnetic tomographic imaging includes a wearable/man-portable boundary apparatus adapted to receive a biological object within, a position determination system, electromagnetic transmitting/receiving hardware, and a hub computer system. The electromagnetic transmitting/receiving hardware collectively generates an electromagnetic field that passes into the boundary apparatus and receives the electromagnetic field after being scattered/interferenced by the biological object within. The hub computer system performs electromagnetic tomographic imaging based on the received electromagnetic field.

Abstract: A vibration transducer includes a silicon single crystal vibration beam provided over a silicon single crystal substrate, the vibration beam having a sectional shape that is longer in a direction perpendicular to a surface of the silicon single crystal substrate than in a direction parallel with it, a shell made of silicon, surrounding the vibration beam with a gap, and forming a vacuum room together with the silicon single crystal substrate, a plate-like first electrode plate disposed parallel with the surface of the silicon single crystal substrate, the first electrode plate having one end connected to the vibration beam, plate-like second and third electrode plates disposed parallel with the surface of the silicon single crystal substrate so as to be opposed to each other with the vibration beam interposed in between, and asperities formed on confronting side surfaces of the vibration beam and the second and third electrode plates.

Abstract: A resonant pressure sensor including one or more resonant-type strain gauges arranged on a diaphragm may include a sensor substrate made of silicon and including one surface on which one or more resonant-type strain gauge elements are arranged and the other surface which is polished to have a thickness corresponding to the diaphragm, a base substrate made of silicon and including one surface directly bonded with the other surface of the sensor substrate, a concave portion formed in a portion of the base substrate bonding with the sensor substrate, substantially forming the diaphragm in the sensor substrate, and including a predetermined gap that does not restrict a movable range of the diaphragm due to foreign substances and suppresses vibration of the diaphragm excited by vibration of the resonant-type strain gauge elements, one or more conducting holes, and a fluid.

Abstract: A resonant pressure sensor includes a first substrate including a diaphragm and at least one projection disposed on the diaphragm, and at least one resonator disposed in the first substrate, at least a part of the resonator being included in the projection, and the resonator being disposed between a top of the projection and an intermediate level of the first substrate.

Abstract: A resonant sensor is disclosed which may be arranged to measure the pressure of a fluid. The resonant sensor comprises a diaphragm which may be exposed to a fluid; two supports provided on the diaphragm and a resonator having at least two beams with each beam being suspended between the two supports. The ends of each beam are attached to a corresponding support at more than one point. By attaching each end of the beams to a support at more than one point, the moments and reaction forces to which the support is subjected may be balanced so that distortion of the support and diaphragm due to vibration of the resonator beams is reduced. Consequently, the resonant sensor is able to provide more precise measurements.

Abstract: A remotely interrogatable pressure and/or temperature measuring device includes at least an acoustic wave sensor including at least one resonator coupled to a first antenna element, and an interrogation system including a second antenna element for transmission and reception. The device further includes an expandable tubular structure, the structure integrating a biocompatible material, and the acoustic wave sensor is encapsulated in the biocompatible material. The second antenna element operates at frequencies above several tens of MegaHertz.

Abstract: A MEMS pressure sensor for sensing the pressure in a sealed cavity of a MEMS device, comprises a resonant MEMS device having a pressure sensor resonator element which comprises an array of openings. The resonant frequency of the resonant MEMS device is a function of the pressure in the cavity, with resonant frequency increasing with pressure. Over the pressure range 0 to 0.1 kPa, the average change in frequency is at least 10?6/Pa. The invention is based on the recognition that for fast oscillation, the elastic force causes the resonance frequency to shift. Therefore, it is possible to sense the pressure by a device with resonance frequency that is sensitive to the pressure.

Abstract: A resonant sensor is disclosed which may be arranged to measure the pressure of a fluid. The resonant sensor comprises a diaphragm which may be exposed to a fluid; two supports provided on the diaphragm and a resonator having at least two beams with each beam being suspended between the two supports. The ends of each beam are attached to a corresponding support at more than one point. By attaching each end of the beams to a support at more than one point, the moments and reaction forces to which the support is subjected may be balanced so that distortion of the support and diaphragm due to vibration of the resonator beams is reduced. Consequently, the resonant sensor is able to provide more precise measurements.

Abstract: An end-effector is provided for use on a micro/nano manipulation device. The end-effector is comprised of: a micropump fluidly coupled to a microtube; a piezoelectric sensing structure disposed in the microtube; and a processing circuit electrically coupled to the sensing structure for determining the force of the fluid flowing through the microtube. The end-effector is a closed loop control-enabled micro/nano manipulation system.

Abstract: A piezoelectric bimorph cantilever is used for determining physical parameters in a gaseous or liquid environment. The sensor works as a driven and damped oscillator. Contrary to common cantilever sensor systems, the piezoelectric film of the bimorph cantilever acts as both a sensor and an actuator. Using at least two resonance mode of the bimorph cantilever, at least two physical parameters can be measured simultaneously in a gas or a liquid. An optimized piezoelectric cantilever and a method to produce the cantilever are also described.

Abstract: A method of manufacturing a pressure monitoring package comprises the steps of mounting a plurality of resonators onto a substrate 1, mounting the substrate 1 in a package base 11, mechanically constraining the package base 11 within a mechanical preloading jig, and adjusting the preload using the jig whilst measuring the frequency of the SAWs until the required frequency is obtained. A lid 7 is then welded onto the package base 11 using a laser welder, after which the preload frequency of the package 10 is fine tuned by using the laser welder to produce laser marks 21-28, 31-38 on the outside of the package 10.

Abstract: An absolute pressure sensor is provided comprising a vibration sensing element such as a piezoelectric element disposed on a vibratable seal. The seal is disposed between two gas spring chambers which are maintained at substantially ambient pressure. The resonant vibration frequency of the seal changes and is proportional with the pressure in the gas spring chambers such that the electrical output of the piezoelectric element will be proportional to the vibration frequency. The frequency of the output of the piezoelectric element is read using suitable electronic circuitry and compared to a set of predetermined pressure/frequency data for calculation of a pressure value.

Abstract: A pressure and vibration sensing apparatus designed to sense pressure together with vibration through one apparatus. The pressure and vibration sensing apparatus includes a case adapted to be mounted in a machine generating vibration and having an inlet communicated with a source of pressure, a pressure sensor sensing pressure variation in the case, and a vibrating member retractably disposed in the case to induce the pressure variation in the case when vibration is generated in the machine.

Abstract: One end of a rod-like pressure-conveying member is disposed in a sensing unit, and the other end extends into and through an insertion hole of an engine. A combustion pressure, to which the other end of the rod-like member is exposed, is conveyed to the sensing unit through the pressure-conveying member for the detection of the combustion pressure. The pressure-conveying member resonates at a knocking frequency fn of the engine and the knocking frequency fn is detected based on the resonance of the pressure-conveying member.

Abstract: A piezoelectric cantilever pressure sensor has a substrate and a piezoelectric cantilever having a base portion attached to the substrate and a beam portion suspended over a cavity. The piezoelectric cantilever contains a piezoelectric layer sandwiched between two electrodes and generates a measurable voltage when deformed under pressure. The piezoelectric cantilever pressure sensor can be manufactured at low cost and used in various applications including fingerprint identification devices.

Abstract: A piezoelectric cantilever pressure sensor array is disclosed. The piezoelectric cantilever pressure sensor array contains a substrate, a readout circuit, and piezoelectric cantilever pressure sensors electrically connected to the readout circuit. Each piezoelectric cantilever pressure sensor contains an elongate piezoelectric cantilever mounted at one end on the substrate and extending over a cavity. The piezoelectric cantilever contains a piezoelectric layer sandwiched between two electrodes and generates a measurable voltage when deformed under pressure. The piezoelectric cantilever pressure sensor array can be manufactured at low cost and used in various applications including fingerprint identification devices.

Abstract: A silicon resonant type pressure sensor has a sensing diaphragm to which a measuring pressure is to be applied; and a vibrating beam which is embedded on the sensing diaphragm, and which is made of a semiconductor, wherein the vibrating beam further has a vibrating beam body having first and second vibrating beams which are allocated in parallel each other, and at least one connecting beam portion which couples the first vibrating beam and the second vibrating beam, a driving vibrating beam portion which is fabricated on a side of at least one side face in an axial direction of the first and second vibrating beams, and which is made of a conductor, and detection vibrating beam portions which are fabricated on sides of another side face in the axial direction of the first and second vibrating beams respectively, and which are made of a conductor.

Abstract: A semiconductor component for a semiconductor substrate, in which a first section and a second section are provided, and in which the pore structure of the first section differs from the pore structure of the second section.

Abstract: A high-sensitive and high accuracy vibrating type pressure sensor (1) allowing a corrosive gas pressure to be directly applied thereto, having a heat resistance, and having no room for mixing of noise into a vibrator, comprising a stainless steel pressure receiving diaphragm (4) for receiving a fluid pressure P on a rear surface side, the vibrator (12) formed on the front surface side of the pressure receiving diaphragm (4), a wall body (8) disposed so as to surround the periphery of the vibrator (12), and a permeable part (20) for light transmission for changing an internal space in which the vibrator (12) is present into a vacuum chamber (10) by closing an opening part (8a) in the wall body (8), whereby, since the diaphragm (4) is formed of the stainless steel with corrosion resistance, the sensor can also be applied to corrosive fluid, since circuit wiring is eliminated from the vibrator (12) and the vibrator is isolatedly disposed in the vacuum chamber (10), mixing of electromagnetic noise can be eliminat

Abstract: Apparatus and methods for performing remote detection of physiological activity are described. One aspect of the invention involves obtaining information concerning respiration and heart function. In one embodiment, the invention includes a source containing an oscillator configured to illuminate the subject with electromagnetic signal beam and a receiver configured to observe changes in the amplitude of the electromagnetic signal reflected by the subject.

Abstract: A resonant microbeam pressure sensor is disclosed, comprising a microbeam suspended by a diaphragm at one or more points by suspension elements. Pressure applied to the diaphragm will cause the resonance frequency of the beam to shift. This shift is detectable and proportional to the pressure. The device is manufactured by surface micromachining.

Abstract: A resonant microbeam pressure sensor is disclosed, comprising a microbeam suspended in a diaphragm in at least one point by suspension elements. Pressure applied to the diaphragm will cause the resonance frequency of the beam to shift. This shift is detectable and proportional to the pressure, The device is manufactured by surface micromachining.

Abstract: The invention relates to a resonance based pressure transducer system, insertable into a living body for the in vivo measurement of pressure. It comprises a pressure sensor (2) having a mechanical resonator (16), the resonance frequency of which is pressure dependent; and a source of ultrasonic energy (4). The sensor (2) is mechanically coupled to said source (4) of ultrasonic energy, and the sensor and the source of ultrasonic energy are provided on a common, elongated member (6) at the distal end thereof. A system for pressure measurement comprises an AC power supply, a resonance based pressure transducer system, and a control unit for controlling the supply mode of the AC power, and for analyzing a resonance signal emitted from the resonance based pressure transducer system.

Abstract: A two-piece vibrating beam force sensor is created by utilizing one thickness of quartz for the outer mounting structure. This outer mounting structure in the case of a pressure sensor includes the mounting structure, the flexure beams and the lever arm and, in the case of an acceleration sensor, includes the mounting structure, the parallel flexure beams and the proof mass. An inner quartz structure made of a double-ended tuning fork vibrating beam assembly which provides an electrical output indicative of tension or compression applied to the beam assembly. The vibrating beam assembly is mounted on the outer quartz structure with epoxy resin or low melting temperature glass frit and suitable electrodes for stimulating the vibrating beams into vibration are provided. The resultant structure is an inexpensive, easily produced, yet highly accurate vibrating beam force sensor.

Abstract: A resonant microbeam pressure sensor is disclosed, comprising a microbeam suspended in a diaphragm in at least one point by suspension elements. Pressure applied to the diaphragm will cause the resonance frequency of the beam to shift. This shift is detectable and proportional to the pressure. The device is manufactured by surface micromachining.

Abstract: A rate sensor has a tine cut from a silicon substrate and resiliently mounted by two integral flexure beams. An electrostatic actuator drives the tine to vibrate in its plane. The tine supports two tunnel pick-offs in the form of spikes projecting from the tine, the tips of the spikes being positioned below a pick-off plate. In operation, the plate is moved down until it is closely spaced from the spikes and a tunneling current is produced. One spike is positioned below a recess so that there is a sharp fall in current when the spike passes beneath the recess, this signal being used to indicate the amplitude and frequency of vibration. The tunneling current output from the other spike indicates the separation from the plate. Rotation of the sensor about an axis y in the plane of vibration of the tine causes displacement of the tine at right angles, which is sensed by the tunnel pick-off.

Abstract: A pressure sensor has a high degree of accuracy over a wide range of pressures. Using a pressure sensor relying upon resonant oscillations to determine pressure, a driving circuit drives such a pressure sensor at resonance and tracks resonant frequency and amplitude shifts with changes in pressure. Pressure changes affect the Q-factor of the resonating portion of the pressure sensor. Such Q-factor changes are detected by the driving/sensing circuit which in turn tracks the changes in resonant frequency to maintain the pressure sensor at resonance. Changes in the Q-factor are reflected in changes of amplitude of the resonating pressure sensor. In response, upon sensing the changes in the amplitude, the driving circuit changes the force or strength of the electrostatic driving signal to maintain the resonator at constant amplitude.

Abstract: A micromechnical sensor having a polysilicon beam that is an integral part of the diaphragm resulting in a frequency of the beam that is a direct result of the pressure applied to the external surface of the diaphragm. Fabrication of this resonant microbeam sensor has no backside wafer processing, and involves a process and layout independent of wafer thickness for high yield and robustness. Both the diaphragm and resonant beam are formed from polysilicon. The sensor may have more than one resonant beam. The sensor beam or beams may be driven and sensed by electrical or optical mechanisms. For stress isolation, the sensor may be situated on a cantilevered single crystal silicon paddle. The sensor may be recessed on the isolating die for non-interfering interfacing with optical or electrical devices. The sensor die may be circular for ease in mounting with fiber optic components.

Abstract: A vortex flowmeter employs a differential pressure transducer converting oscillation in a differential pressure to an alternating electrical signal, wherein the differential pressure transducer comprises a pair of pressure compartments (10 and 11) respectively receiving two fluctuating fluid pressures respectively existing at two fluid regions located on the two opposite sides (8 and 9) of a vortex generator (3) respectively through a pair of tubings (13 and 14, 43 and 44, or 61 and 62) or through a pair of holes (69 and 70, or 72 and 73) embedded within the wall of the flow passage.

Abstract: An improved gas pressure gauge is disclosed that extends the linear range of pressure dependent damping to higher pressures by placing a stationary member in very close proximity to the vibrating member. This range of linear dependent damping is also extended to lower pressures by making the vibrating member large in area relative to its small distance from a fixed planar member, which can also serve as its supporting member, by making it vibrate in a direction perpendicular to the fixed planar member, and by making the springs that support the vibrating member from a high Q and conductive material, such as boron doped single crystal silicon. These features for extending the range to higher and lower pressures can be built separately into two independent vibrating elements that can be used individually or in tandem, or they can be built into a single vibrating element that can be made to vibrate in two modes, one parallel and one perpendicular to a fixed member.

Abstract: A transducer converting an oscillation in fluid pressure into an alternating electrical signal comprises a transducer body including a first pressure compartment disposed intermediate a second and third pressure compartment, and separated by from the second and third pressure compartments respectively by two thin partitioning walls, and a relative vibratory motion sensor detecting the relative vibratory deflection between the two thin partitioning walls, wherein the relative vibratory motion sensor generates an alternating electrical signal representing the oscillation in fluid pressure existing in at least one of two pressures respectively introduced into the first pressure compartment and into the combination of the second and third pressure compartments.

Abstract: A pressure transducer comprising at least one diaphragm formed in a wafer of semiconducting material, the at least one diaphragm being spaced from a first surface of the wafer, a first layer of semiconducting material disposed over the at least one diaphragm, the first layer forming at least one resonating beam over the at least one diaphragm, and a plurality of resistor elements formed from a third layer of semiconducting material disposed over the at least one resonating beam, and isolation means for dielectrically isolating the at least one resonating beam from the at least one diaphragm.

Abstract: A method and apparatus for measuring differences between forces, pressures, and combinations thereof. One or more force or pressure deformable members, preferably metal bellows, are internally connected by rigid linkage which is in turn connected to a component for translating force magnitude into corresponding electromagnetic signals. In an embodiment, the apparatus has a pressure chamber (40), an elastic vibrating member (50), an electromagnetic coil (60), a linkage (33), a rigid body (30), a body extension (35), and a bellows (22) defining in part a reference chamber (20). Bellows (22) is attached at bellows fixed end (23) to rigid body (30) and is deformable in response to a difference between a bellows internal reference pressure P.sub.0 and any pressure P.sub.1 external to bellows (22), such as in pressure chamber (40). Elastic vibrating member (50) is connected at a first end to linkage (33). Linkage (33) projects rigidly from an interior face of movable end (24).

Abstract: A reactionless single beam vibrating force transducer utilizes counterbalances at opposite ends of the beam that rotate in directions opposite to the ends of the vibrating beam to reduce rotational and normal forces transmitted to the end supports for the beam. The proportions of the counterbalances relative to the size of the beam may be chosen to reduce forces in a direction normal to the beam to zero at the expense of some rotational moments at the end of the beam support, or to reduce moments at the expense of some normal force. The relative amounts of residual rotational moments and normal force can be adjusted to suit particular applications. Flexures may also be utilized to reduce the rotational moments transferred to the beam support even further.