Abstract: It comprises a) a cylindrical base (1) formed of an axial barrel (2) protruding from an annular shoulder (3), through both of which there passes an axial hole (4), b) a washer (6) made of a piezoelectric material slipped over the barrel, c) means (71, 72) for picking off the electrical voltage there is between two radial faces of said washer, e) an annular mass (9), also slipped over the barrel (2) and e) a retaining means collaborating with the annular shoulder (3) to trap said washer (6) and said mass (9) between them. The retaining means consists of a bulge (17) protruding radially from said barrel (2) and formed of the material of a predetermined portion thereof, deformed under an axial force for crushing said base (1).

Abstract: An instrumented sports apparatus includes a closely spaced array of discrete sensor elements coupled to a contact surface thereof for converting a contact force between the contact surface and an object into a plurality of discrete output signals. The signals are processed and information based thereon generated, which is representative of one or more parameters of interest. In an exemplary embodiment, as instrumented golf club displays information such as club head speed, club head angle, and club head elevation upon impact with a golf ball, permitting the golfer to adjust his swing on the next stroke. Since the instrumentation and display are entirely self-contained in the club, a golfer is not constrained in the use of the club and may enjoy the benefits thereof during play on a golf course.

Abstract: This invention relates to an optimization method for driving a piezoelectric actuator by dynamic detection of its electromechanical characteristics, as well as to a device, in particular a phacoemulsifier based thereupon. The piezoelectric actuator includes a voltage driven, two-terminal piezoelectric transducer. The method for detection of its electromechanical characteristics is such that the drive of the transducer is cyclically discontinued in order to detect the characteristic parameters of its free motion by detection of the parameters of the signal generated by the transducer at the ends of the two terminals.

Abstract: A pressure and temperature transducer includes an elongate housing formed from double rotation cut crystal quartz, an elongate plate-like resonator formed from double rotation cut crystal quartz capable of vibrating under an applied electric field located within the housing, the resonator being formed in unitary construction with the housing. The long edges of the resonator are connected to the interior walls of the housing, and short edges of the resonator are free and extend across the interior of the housing in a substantially continuous curve. Electrodes are located on opposite faces of the resonator for applying an electric field which causes the resonator to vibrate. End caps, formed from double rotation cut crystal quartz, are provided at each end of the housing. A borehole tool includes a tool body which can be positioned in a borehole, a probe for sampling fluid in the borehole; and a pressure and/or temperature transducer, connected to the probe for making measurements on the fluid.

Abstract: In a pressure wave sensor comprising a cylindrical housing having a piezo electric element disposed therein, which is forced by a spring against the front face of the housing, the front face consists of a metal foil and a pressure pad consisting of a soft metal is disposed between the piezo electric element and the metal foil, the spring force being sufficiently large to load the pressure pad beyond its yield limit.

Abstract: An acoustic or vibration sensor particularly useful in detecting nano-vibrations includes a body 40 having a generally C-shaped cross-sectional configuration. A base 44 is positioned within the body 40 and has at least one protrusion 68 extending from the base 44 intermediate end portions 48 of the C-shaped cross-section. A film 14 extends about the base 44 and over the protrusion 68 to form a space between a portion of the base 44 and the film 14. The film 14 is engaged with the end portions 48 of the C-shaped cross-section and urged at least partially into the space to place a desired tension on the film.

Abstract: The invention is an acceleration-compensated pressure transducer having only one signal crystal array joined by two masses and connecting elements to an inner part having a flange. The installation housing of the pressure transducer is joined to the flange and touches the inner part of the pressure transducer at no other point. Hence, the inner part constitutes a freely vibrating element, which with the masses and the stiffnesses optimized, measures only the pressure signal.

Abstract: To draw samples from a source of liquid, a pumping system measures the amount of liquid being pumped by detecting pump cycles and calculating the pumped liquid from this measurement and stored data including conduit size, pressure head and statistical data to correlate detected pump cycles with volume of liquid pumped. Pressure pulses cause by a peristaltic pump are sensed by a piezoelectric film positioned on an inlet conduit connecting the pump to the source of water and, when the liquid reaches a predetermined point determined by the nature of pulses are counted to determine the number of pump cycles.

Abstract: A main structure is intended to engage and disengage an flow-injection type piezoelectric sensor and is composed of a movable stand, a lifting mechanism, and a fixed injection portion. The movable stand is capable of being actuated by a rotary shaft of the lifting mechanism to move upwards or downwards. The movable stand is provided with a retaining slot capable of catching and releasing the flow-injection type piezoelectric sensor. When the movable stand is lifted, a transparent end of the fixed injection portion is in an intimate contact with a planar surface of the flow-injection type piezoelectric sensor which is caught in the retaining slot of the movable stand. A liquid test sample is thus injected into a charge channel of the transparent end such that the liquid test sample flows on the surface of a piezoelectric crystal located in an opening of the planar surface of the flow-injection type piezoelectric sensor for detecting the presence of a target molecule in the test sample.

Abstract: A sensor device includes a base body 12 having a vibrating portion 14, a piezoelectric element 20 fixed onto one surface of the vibrating portion 14 and having a piezoelectric film 22 and a pair of electrodes 24a, 24b which are in contact with the piezoelectric film 22, a space 16 that allows a fluid to lead to the other surface of the vibrating portion 14, and introduction holes 18 that communicate with the space 16, and the sensor device 10 is in a longitudinal shape. A recess 15 which contains at least an opening end of the introduction hole 18 on the surface side of the sensor device 10 in its region and extends up to the rear end portion 10' of the sensor device is formed on the surface of the sensor device 10 by a protrusion 13 disposed on the surface of said sensor device so as to extend substantially continuously from the periphery of the introduction holes 18 to the rear end portion 10' of said sensor device.

Abstract: A pressure sensor comprising a flexible substrate, and a piezoelectric element for detecting a pressure,. The piezoelectric element includes a piezoelectric layer and an electrode layer which are formed on at least one of the opposite sides of the flexible substrate such that the piezoelectric layer is disposed between the flexible substrate and the electrode layer. The pressure sensor is characterized by the formation of the piezoelectric layer by hydrothermal synthesis or hydrothermal crystallization method.

Abstract: A tactile sensor includes, under a control key accessible to the user, at least one piezo-electric member which is responsive through the control key to any depression of the latter. For connecting it to an electrical circuit of any kind, the piezo-electric member is sandwiched between a top or forward metal electrode to which it is attached and a bottom or rearward metal electrode which is attached to a support of any kind. For holding the piezo-electric member in place relative to the support of the bottom electrode, the top electrode is fixed to the support by at least one fixing point. Applications include controlling various devices such as on/off switches, changeover switches, dimmers or keypads.

Abstract: The present invention provides a pressure sensing device for sensing pressure which is adapted to provide an electrical indication of a sensed pressure. The pressure sensing device has a top lamination, a middle lamination, and a bottom lamination. A pressure sensor is located within an aperture defined in the middle lamination. First and a second electrical connectors, being exposed by the aperture, make electrical connection with the pressure sensor when pressure or compression is applied to the pressure sensing device. An output electrical signal indicative of the applied pressure is produced when the pressure sensor has electrical contact with the electrical conductors.

Abstract: A method for detecting the solid particles contained in a fluid, by the use of a particle sensor having a flow path of a fluid, having a fluid inlet and a fluid outlet, and a sensor element provided in the flow path, which comprises (a) a vibrating section having such a mass that is sensitive to the collision of solid particles contained in the fluid, with the vibrating section and (b) a detecting section for detecting the vibration of the vibrating section caused by the collision and converting the vibration to electric signals.

Abstract: A particle sensor includes, a sensor element including (a) a vibrating section having a mass that is sensitive to the collision of solid particles contained in a fluid with the vibrating section and (b) a detecting section for detecting the vibration of the vibrating section caused by the collision and converting the vibration to electric signals, a housing for fixing said sensor element, an inlet nozzle forming a fluid inlet, and an outlet nozzle forming a fluid outlet. In the particle sensor, the outlet nozzle is provided so that the sensor element is between the inlet nozzle and the outlet nozzle, throughholes are formed in the sensor element in at least part of the vicinity of the vibrating section, and the fluid entering the particle sensor from the inlet nozzle collides with the sensor element, passes through the throughholes and leaves the particle sensor from the outlet nozzle.

Abstract: An improved device for measuring pressures, comprising a silicon membrane or diaphragm which is exposed, on its two faces, to two pressures whose difference is to be measured. A resonant element is provided on one face of the diaphragm, which is treated by selective chemical etching, and is mechanically coupled to the diaphragm so that its resonance frequency varies as a consequence of the deformation undergone by the diaphragm.

Abstract: A piezo film sensor switch or a pyro film sensor switch for an electric candle or lamp, or birthday card or birthday box. The switch is omnidirectional and includes a housing having a wall with at least one opening; a piezo film within the housing and having at least two sides, one of the sides facing the opening; and two electrical conductors each in electrical contact with a respective one of the sides of the piezo film, the piezo film being responsive to air currents of sufficient magnitude to mechanically actuate the piezo film to pass electrical current through the two electrical conductors. Pyro film may be arranged in place of the piezo film in the same manner.

Abstract: A sensor device adapted to detect at least one of a particle and a bubble in a fluid, includes a fluid nozzle defining a center of fluid flow; and a plurality of sensor elements for converting an impact of one of a particle and a bubble into an electrical signal, wherein a first sensor element is arranged closer to the center of fluid flow than a second sensor element. The sensor device includes a number of diaphragm sensor elements each having a sufficiently small mass for responding to a collision with the particle, and an apparatus for converting a vibration of the diaphragm portion into an electrical signal so as to detect the vibration. The multiple elements are arranged in the fluid flow stream such that different size particles will preferentially strike different elements.

Abstract: A particle sensor includes a flow path of a fluid, having a fluid inlet and a fluid outlet, and a sensor element provided in said flow path, which comprises (a) a vibrating section having such a mass that is sensitive to the collision of solid particles contained in the fluid, with the vibrating section and (b) a detecting section for detecting the vibration of the vibrating section caused by said collision and converting the vibration to electric signals. The sensor has a means capable of selectively detecting any vibration of the vibrating section having a frequency higher than the primary resonance frequency of the sensor element. This particle sensor has improved sensitivity to solid particles and can distinguish the signals generated by collision of solid particles, from the signals generated by collision of bubbles, at a high accuracy.

Abstract: A dust sensing apparatus uses a transducer element oscillating at a resonant frequency to detect changes in dust concentration. The transducer is fabricated from a polymer material which oscillates when a voltage is applied. The presence of dust affects the oscillation frequency. Dampening of the frequency by the dust presence changes the electrical resistance provided by the transducer. Electronic circuitry computes the level of dust by measuring and controlling the level of the AC signal required to maintain the oscillation frequency by monitoring the resistance.

Abstract: A sensor device includes a base body 12 having a vibrating portion 14, a piezoelectric element 20 fixed onto one surface of the vibrating portion 14 and having a piezoelectric film 22 and a pair of electrodes 24a, 24b which are in contact with the piezoelectric film 22, a space 16 that allows a fluid to lead to the other surface of the vibrating portion 14, and introduction holes 18 that communicate with the space 16, and the sensor device 10 is in a longitudinal shape. A recess 15 which contains at least an opening end of the introduction hole 18 on the surface side of the sensor device 10 in its region and extends up to the rear end portion 10' of the sensor device is formed on the surface of the sensor device 10 by a protrusion 13 disposed on the surface of said sensor device so as to extend substantially continuously from the periphery of the introduction holes 18 to the rear end portion 10' of said sensor device.

Abstract: A quartz crystal resonator is excited in two different modes at the same time such that the mass change and the temperature change can be measured independently. In using such a quartz crystal the change in mass can be calculated accurately and in real time, independent of temperature effects.

Abstract: A piezoelectric pressure sensor for detecting pressure in a combustion chamber of an internal combustion engine includes a backing plate secured within a housing. The sensor also includes a resilient prestress plate stacked on the backing plate. The resilient plate is formed of silicone elastomer. A sensor element is stacked on the resilient plate. The sensor element is composed of a piezoelectric material formed from a mixture of lead titanate and lead zirconate. A thermally insulating plate is stacked on the sensor element and a diaphragm plate is stacked on the thermally insulating plate and also secured to the housing. The diaphragm plate is exposed to combustion atmosphere and is adapted to transmit a pressure being determined onto the sensor element.

Abstract: A resonator (1) is vibrating close to its resonance frequency. The vibration is excited by one or a first transducer (2) connected to an oscillator (11). The vibration is measured by the transducer (2) or a second transducer (3) and stabilized by a phase-locked feedback loop comprising a phase sensitive detector (33), a feedback controller (36), a phase shifter (17) and means (15) to evaluate the measured frequencies. In order to measure the damping of the resonator (1), the phase in the phase shifter (17) is alternately set to two different values. The difference between the frequencies corresponding to these two phase values is a measure for the damping of the system. One or more switches (19, 28, 27) and a gate generator (16) make sure that excitation and measurement do not occur at the same time. Thereby, any cross-talk between driving and sensing transducers is completely eliminated. Also, a single transducer can be used to both excite and measure the vibration.

Abstract: A sensor element for detecting solid particles in a fluid includes: a detecting unit including a piezoelectric film consisting essentially of a ceramic material, a first electrode coated onto at least a portion of the outer surface of the piezoelectric film, and a second electrode coated onto at least a portion of the inner surface of the piezoelectric film; a vibrating portion consisting essentially of a second ceramic material, the detecting unit being placed on the vibrating portion so that the second electrode is coated onto at least a portion of the vibrating portion; and a fixing portion for fixing the vibrating portion so that the vibrating portion may vibrate. At least one of the detecting unit and the vibrating portion contacts with a solid particle in the fluid so that the piezoelectric film converts the vibration into an electric signal. A particle sensor includes the sensor element. The sensor element and the particle sensor are excellent in particle detection precision and durability at low cost.

Abstract: A mechanical shock sensor including a diaphragm suspended about its edge to an elevated pedestal and a pattern of piezoelectric material attached to the diaphragm surface. A proof mass is attached beneath the diaphragm surface and centered along a vertical axis passing through the diaphragm and the concentric piezoelectric materials. Electrical conductors are attached to the first and second concentric electrically conductive layers on piezoelectric material and are connected to a circuit capable of responding to the piezoelectric signals developed thereby.

Abstract: A vehicle detector for installation on the surface of a multi-lane road, comprising at least a coaxial detector cable provided with a central conductor, a metallic cladding and a filler material between the cladding and the conductor. The coaxial detector cable comprises at least one region which is referred to as the active region and in which the filler material is mechanoelectric, and also comprises at least one adjoining region which is referred to as a neutral region and in which the filler material is neither mechanoelectric nor potentially mechanoelectric.

Abstract: A flat seal having a first and a second sealing surface made of polymer material is disclosed. Each of the polymer sealing surfaces is made of a formed-fabric-reinforced cover layer. At least two of these cover layers together provide a flexible, electrical printed-circuit board, whose material completely surrounds electrical interconnect traces in the sealing areas. The interconnect traces are provided with connecting conductors, which are brought with terminal pads out of the printed-circuit board. The material of the cover layers has an electrical resistance of at least 10.sup.8 ohm and provides insulation for the interconnect traces.

Abstract: A piezoelectric sensor probe comprises an elongate insulative support member supporting a plurality of piezoelectric sensing elements spaced along the length of the member, the support member has respective conductors extending from one end of the member to each of the sensing elements for conducting electrical signals to and from each sensing element.

Abstract: An axial-flow particle sensor has a sensor element and a housing. The outlet of fluid is placed at the opposite side of the inlet of the fluid, throughholes are formed at the circumference of the vibrating portion of the sensor element, and the vibrating portion of the sensor element is placed on the extension of the flow of the fluid so that the fluid entering from the inlet flows through the throughholes and flows out from the outlet. Two or more throughholes may be formed symmetrically with the axis. The throughhole may be formed on a ceramic substrate, or may be a gap between the ceramic substrate and the housing.

Abstract: An improved piezoelectric sensor for detecting pressure, vibration, acceleration or the like physical quantity is disclosed. The pressure sensor to be attached to a cylinder block of an internal combustion engine includes a main body adapted to be attached to the cylinder and defining an axially extending hole therewithin, a diaphragm attached to one end of the main body for closing the hole; and a piezoelectric element disposed within the hole so that the pressure within the cylinder is transmitted to the piezoelectric element through the diaphragm. The piezoelectric element is a circular or polygonal disc with a thickness of 0.3-1.5 mm and is formed of a single crystal piezoelectric ceramic having a Curie temperature greater than 500.degree. C., such as LiNbO.sub.3.

Abstract: A small, compact, easily mountable ultrasonic transducer for measuring the filling level in a container is provided, which transducer transmits virtually no oscillation energy to the container, having a can-shaped transducer housing (1), an electronics housing (2) connected to the transducer housing (1), a transducer element (4), arranged in the transducer housing (1), for the transmission and reception of ultrasonic pulses, a union ring (3) for the sound-decoupling securing of the ultrasonic transducer on the container, in which ring the transducer housing (1) is supported coaxially with respect to the union ring (3) and is fixed therein against displacement in the axial direction, and two resilient elements (7, 8) which are arranged between the transducer housing (1) and the union ring (3) and by means of which the transducer housing (1) and the union ring (3) are held spaced apart from each other in the radial direction in such a way that there is no direct mechanical coupling between them in the radial di

Abstract: A detecting apparatus which includes a balancer which generates a moment of rotation around an axis; and a pressure sensing sheet which contacts at one or more contact points with the balancer and outputs a pressure signal corresponding to a force acting on the contact point and depends on the moment of rotation. An attitude detecting apparatus and a detecting apparatus for difference of attitude each of which includes, the detecting apparatus; and an arithmetic circuit which receives a pressure signal at predefined time intervals in order and processes a calculation.

Abstract: The presence of bubbles on such photographic material, as is well known, results in significant defects in the photographic materials produced so that it is important, in the manufacture of such photographic materials, to detect the presence of such bubbles in the liquid emulsion and to take appropriate remedial action. Described herein is a bubble detector comprising a conduit for liquid to be monitored, the conduit having opposing flattened, generally parallel walls, and a transducer engaged with one of the generally parallel walls and operable to apply alternating displacements to one of the generally parallel walls, at an ultrasonic frequency, in a direction generally normal to the generally parallel walls to transmit sonic or ultrasonic waves through liquid passing through the conduit.

Abstract: A method of making a sensor wherein flexible conduit means is assembled with a fixture having a strain-sensitive film and electrical connections are made to the film whereby variations in fluid pressure in the conduit means can be detected.

Abstract: A sensor element for detecting solid particles in a fluid includes: a detecting unit including a piezoelectric film consisting essentially of a ceramic material, a first electrode coated onto at least a portion of the outer surface of the piezoelectric film, and a second electrode coated onto at least a portion of the inner surface of the piezoelectric film; a vibrating portion consisting essentially of a second ceramic material, the detecting unit being placed on the vibrating portion so that the second electrode is coated onto at least a portion of the vibrating portion; and a fixing portion for fixing the may vibrate portion so that the vibrating portion vibrates. At least one of the detecting unit and the vibrating portion contacts-with a solid particle in the fluid so that the piezoelectric film converts the vibration into an electric signal. A particle sensor includes the sensor element. The sensor element and the particle sensor are excellent in particle detection precision and durability at low cost.

Abstract: A non-contaminating pressure sensor module having an isolation member is disclosed. The isolation member isolates a pressure sensor within the transducer module from exposure to fluids flowing through a conduit in the module. The transducer module may be positioned in-line within a fluid flow circuit carrying corrosive materials, wherein the pressure transducer module produces a control signal proportional to either a gauge pressure or an absolute pressure of the fluid flow circuit. The pressure transducer module of the present invention also avoids the introduction of particulate, unwanted ions, or vapors into the flow circuit.

Abstract: A movement sensor (40) for a process device has a sensor tip (42); means (41) for transmitting the vibrations from the sensor tip to a transducer means (43), the transducer means electrically detecting the resulting vibrations as movement occurs and producing an output signal. Means (70) can be provided for filtering the output signal below and above respective predetermined frequencies and producing a movement detection signal when the output signal lies between the predetermined frequencies.

Abstract: The present invention relates to a transducer with a piezoelectric crystal for parking aids in automotive vehicles. Such transducers must be sealed against steam jets. This object is achieved by the present invention by means of a plug including projections forming an evacuatable chamber in conjunction with the inner wall of a housing bowl. Developments of the present invention relate to the protection and sealing of the diaphragm retainer, which is part of the transducer, against moisture and mechanical displacement due to vibrations and other environmental influences.

Abstract: A pressure sensor having enhanced sensitivity without loss of accuracy over a broad pressure range. The sensor includes a resonator element sandwiched between two hollow end caps to form a sealed assembly. The sidewall thickness of the end caps abutting the resonator element is greater than the sidewall thickness at an area longitudinally spaced from the resonator, and the two dimensions may be selected to enhance sensitivity while maintaining accurate sensor performance. End cap endwalls of non-uniform thickness are employed with the thinnest endwall portion at the center and the thickest at the lateral periphery of the endwall. The rate of increase of end wall thickness toward the periphery may be modified to control the upper end of the pressure range in which the sensor is operable.

Abstract: A vibrating beam force-frequency transducer has a flat elongate blade designed to be interposed between two elements for applying a longitudinal force to the blade. The middle portion of the blade constitutes two lateral beams which are separated by a gap and which are interconnected by terminal portions of the blade. The beams carry electrodes for setting the beams into vibration in the plane of the major faces of the blade and for measuring the frequency of vibration. The terminal portions have extensions parallel to the beams and directed towards the middle of the blade in the longitudinal direction. The extensions are arranged for connecting them to the elements in zones that are closer together than are the terminal portions.

Abstract: In an external force measuring system comprising a piezoelectric element 61 or producing a charge when acted on by an external force, and a charge amplifier 7 chargeable with a variation in the charge produced by the piezoelectric element to output a voltage signal, the charge amplifier 7 comprises a feedback loop having an on-off controllable switch 8 connected in parallel therewith. The switch 8 is on-off controlled by a comparator 81 for comparing the output voltage with a reference value and is closed while no external force acts on the element.

Abstract: An active matrix surface pressure input panel comprises a piezoelectric sheet having electrode lines formed thereon and coupled to a piezoelectric body for vibrating the sheet at a given reference frequency. When an object having surface variations, such as a fingertip, is pressed against the sheet, corresponding underlying portions of the sheet vibrate at frequencies that differ from the reference frequency. The local vibration frequencies are detected by electrode lines applied to opposing sides of the sheet, preferably in an X-Y grid, so that the relative locations of the sheet from where the detected signals emanate can be determined. The surface pressure input panel exhibits high definition over a relatively large detection area so that complicated surfaces, such as fingerprints, can be accurately detected and reproduced.

Abstract: A pressure sensor comprises a movable structure which is movable in accordance with a pressure applied thereto. A piezoelectric transducer is employed against which a pressure is applied when the movable structure is moved. The transducer has opposed electrodes between which a voltage is generated when the transducer is pressed. The capacitance between the opposed electrodes increases with increase of temperature. A dielectric member is arranged in the vicinity of the piezoelectric transducer. The dielectric member has opposed electrodes the capacitance between which decreases with increase of temperature. The piezoelectric transducer and the dielectric member are electrically connected in series.

Abstract: A diaphragm portion 20 causes deflection, when high-temperature fluid pressure acts on the pressure sensing surface A of the diaphragm portion 20. This deflection is transmitted via pressure transmitting members 7, 8 to a deflection sensing member 6 which generates an electric signal in response to a pressure received.The diaphragm portion 20 has a recess portion 21 at its center. The recess portion 21 is symmetrical about a central axis of the diaphragm portion 20. A tip end of the pressure transmitting member 7 is brought into contact with the recess portion 21 at a central point. A tapered portion 2d of the diaphragm 20 has a thickness of t.sub.3 which is not larger than the thickness t.sub.1 of an outer peripheral portion 2b or t.sub.2 of a central bottom portion 2c. Furthermore, a heat insulating plate can be provided on the diaphragm to protect the surface A of the diaphragm portion from heat radiation of high-temperature fluid.

Abstract: A relative vibration sensor includes a transducer container vessel including a cavity surrounded by two parallel deflective walls on two opposite sides and rigid walls on other sides, a piezo electric disc element disposed within the cavity intermediate the two parallel deflective walls, at least two electrodes respectively belonging to two opposite halves of the piezo electric disc element respectively located on two opposite sides of a reference plane intersecting with the two parallel deflective walls of the cavity in a substantially perpendicular relationship, and a pair of elongated vibration sensing members respectively extending from the two parallel deflective walls of the cavity towards an approximately common direction perpendicular to the reference plane, wherein vibrations of two mechanical members respectively transmitted to the pair of elongated vibration sensing members generate two alternating electrical signals respectively from the two opposite halves of the piezo electric disc element, whic

Abstract: An AT cut quartz crystal resonator has an unbalanced electrode geometry to induce a particularly strong electrical field in a surface of the resonator adjacent a medium. The electrical field will interact with ions and dipoles in the medium and may be used to accurately and repeatably measure the electrical characteristics of the medium. Specific examples are provided illustrating the use of a sensor designed in accord with the invention in sensing dilute electrolytes, and other applications are contemplated.

Abstract: A mechanical/thermal stress transducer consisting of a piezo-pyroelectric material in electrical communication with a electroluminescent material, an electrode positioned between the piezo-pyroelectric material and the electroluminescent material forms the electrical communication at disjunct intervals so that the luminous intensity of light emitted by the electroluminescent material at any point is related to the mechanical/thermal stress acting at that point on the transducer. Selected applications of the transducer are included.

Abstract: A force or fluid pressure transducer comprises a plate-like crystal. The force, to be measured, is applied by two seatings disposed on opposite edges of the crystal. The transducer can measure pressure when a diaphragm is added to provide the force.Two portions of the crystal are maintained in continuous oscillation by feed-back circuits. These portions change their frequencies by different amounts when the force is changed. The difference between the two frequencies is a very accurate measure of the force and forms the output of the transducer.Structures to secure the crystal have, in the past, proved difficult to manufacture. The present invention describes a securing structure for the crystal which substantially improves and facilitates securing and housing the crystal to provide high accuracy under all normal working conditions of the transducer.

Abstract: A stress-driven electrostrictive ceramic low-voltage plate voltage sensor based on the principle of the field-coupling between the strain and polarization in the ceramic material of the device. Application of a dithering or driving voltage to a piezoelectric tube thereby generating an oscillating polarization whose amplitude is proportional to an applied low-frequency voltage. A electrostrictive ceramic wafer material affixed to the piezoelectric tube senses this oscillation and generates a displacement current. The displacement current represents a voltage output that is an amplitude modulated carrier whose displaced amplitude is proportional to an applied unknown signal voltage sought to be determined.