Abstract: A pressure capsule/header assembly for a process fluid pressure transmitter is provided. An isolator plug has an isolation diaphragm at a first end thereof and a second end spaced from the first end. The isolator plug has a fill fluid passageway fluidically coupling the first end to the second end. A header has a first end configured to carry a pressure sensor and a second end spaced from the first end. The header has at least one electrical interconnect extending from the first end to the second end. A biaxial support ring is disposed about an outer surface of the header. The biaxial support ring and the header define a tapered interference interface therebetween. The header is welded to the isolator plug at a first weld and the biaxial support ring is welded to the isolator plug at a location that is spaced from the second end of the header.

Abstract: An integrated seal and diaphragm member for a pressure sensor assembly may include a diaphragm portion and a seal portion integral with the diaphragm portion. In some cases, the integrated seal and diaphragm member includes one or more retention features integral with the diaphragm portion and/or the seal portion. In some cases, the seal portion may be thicker than the diaphragm portion and may extend around the perimeter of the diaphragm portion. In some instances, the seal portion may be configured to deform to form a seal with a pressure port of an external component or device without causing the diaphragm portion to move toward the pressure port in any significant way.

Abstract: A sensor body for a flow through pressure sensor includes a strain gage surface to receive a strain gage. The strain gage surface has a curved section and a length extending along a portion of a length of the sensor body. A bore wall thickness is defined as a radial distance between the bore and an outer surface of the sensor body, including the strain gage surface. The curved section can have a substantially greater bore wall thickness over its area relative to the planar surface because a greater responsive surface area for strain measurement is available. Thus a larger strain gage may be used and pressure measurement accuracy increased.

Abstract: In accordance with an embodiment, a MEMS structure is produced on a front side of a substrate. A decoupling structure which has recesses is produced in the substrate, which decoupling structure decouples a first region from a second region of the substrate in terms of stresses. In a rear side, situated opposite the front side, of the substrate, a first cavity is produced by means of a first etching process and a second cavity is produced by means of a second etching process. The first cavity and the second cavity are produced such that the second cavity encompasses the first cavity and such that the second cavity adjoins a base region of the MEMS structure and a base region of the decoupling structure.

Abstract: An electronic system that can be combined with a wind musical instrument with lateral holes comprising a tubular body defining, on the inside, an air column, comprises at least one device for emitting elastic mechanical waves in the body of the instrument, at least one device for receiving elastic mechanical waves positioned to receive the waves emitted by at least one emission device after their propagation in the material of the body of the instrument and designed to provide at least one reception signal characteristic of the waves received and a device for detecting and locating the disturbance induced by an action of closing at least one lateral hole of the instrument, configured to detect and identify a configuration of closing of the lateral holes of the instrument from the analysis of at least one reception signal, the detection and location device positioned removably inside the air column of the instrument.

Abstract: A hydraulic sensor attachment structure includes an accommodating portion, a sensor case, and a lid disposed over the accommodating portion. In the hydraulic sensor attachment structure, an oil passage body includes the accommodating portion and a hydraulic pressure detection port. A hydraulic sensor includes a sensor main body, and the sensor case that covers the sensor main body. The accommodating portion includes a support portion that supports the hydraulic sensor from below. The sensor case includes a detection port portion. The accommodating portion includes a fastening portion and the lid includes a fastening portion. By fastening the fastening portion of the accommodating portion and the fastening portion of the lid by rotating the lid in one direction of the circumferential directions, the sensor case is held by the support portion and the lid in the up-down direction and is fixed to the oil passage body.

Abstract: A pipe damp is for joining submerged pipes provided with flanges. The pipe clamp includes at least two segments connected by at least one hinge. The pipe clamp is further provided with a threaded bolt arranged to open and close the pipe clamp. The pipe clamp is provided with at least one strain gauge arranged to measure the tension of the pipe clamp around the flange of the pipe when the pipe clamp is dosed by the threaded bolt. A method is for tensioning a pipe clamp. Use of strain gauges to measure the tension of a pipe clamp is provided.

Abstract: A measuring arrangement with a ceramic measuring cell and a metal process connection for connecting the measuring cell to a measuring environment, with the measuring cell being fastened in the process connection without gaskets and in a diffusion-resistant fashion, with the measuring cell being fastened at a ceramic ring, which is arranged at a metal ring for fastening in the process connection.

Abstract: Techniques for detecting vacuum loss in a vacuum interrupter are disclosed. For example, a sensing system of a vacuum interrupter includes a sensor including a material that oxidizes in the presence of air and is at least partially positioned in an evacuated space of a vacuum interrupter, the sensor being configured to produce an indication of impedance of the material; and a control system coupled to the sensor, the control system including an electronic processor and an electronic storage that stores instructions that, when executed, cause the electronic processor to access an indication of impedance produced by the sensor, determine a measure of impedance of the material of the sensor based on the accessed indication of impedance, and determine a condition of the evacuated space based on the determined measure of impedance.

Abstract: In a sensor module for measuring a pressure of a fluid, having at least one supporting element, at least one electronic circuit, particularly an integrated circuit, arranged on at least one circuit carrier, and with at least one pressure measuring chip that has at least one pressure measuring membrane, wherein at least sections of the circuit carrier are surrounded by a protective material to protect it from surrounding fluids, it is provided as essential to the invention that the pressure measuring chip and the circuit carrier are arranged vertically one underneath the other, and that the pressure measuring chip is at least partially mechanically decoupled from the supporting element.

Abstract: This disclosure provides example methods, devices and systems associated with flat covered leadless pressure sensor assemblies suitable for operation in extreme environments. In one embodiment, a system may comprise a semiconductor substrate having a first side and a second side; a diaphragm disposed on the first side of the semiconductor substrate; a first cover coupled to the first side of the semiconductor substrate such that it overlays at least the diaphragm, wherein a pressure applied at the first cover is transferred to the diaphragm; and a sensing element disposed on the second side of the semiconductor substrate, wherein the sensing element is used to measure the pressure.

Abstract: A flexible electronic module is provided, including a flexible substrate having a supporting portion, a body portion, and a connection portion, wherein the supporting portion is connected with the body portion via the connection portion; a first trench formed between the supporting portion and the body portion; an electronic component disposed over a portion of the supporting portion; and a conductive line disposed over the supporting portion, the connection portion, and the body portion for connecting the electronic component.

Abstract: Disclosed is a pressure sensor that outputs a temperature change caused in an electrical resistor according to a pressure of a gas, as a resistance change in the electrical resistor. The pressure sensor includes: a base substrate including a recess formed therein, a floating film formed on the base substrate, a heater formed on a surface of the floating film and configured to heat the floating film when a current flows therein, and a temperature sensor formed as the electrical resistor on the surface of the floating film. The temperature sensor changes a voltage drop with respect to a current flowing therein according to the temperature of the floating film.

Abstract: A pressure transducer assembly including: a pressure sensor header; a transducer assembly member; and a joining arrangement disposed at an interface of the header and the transducer assembly member, for joining the header with the transducer assembly member, the joining arrangement including: a recessed female joining element formed in one of the header and the transducer assembly member; and a protruding male joining element formed on the other of the header and the transducer assembly member, the male joining element received in the female joining element.

Abstract: A pressure transducer comprising a corrosion resistant metal diaphragm, having an active region, and capable of deflecting when a force is applied to the diaphragm; and a piezoresistive silicon-on-insulator sensor array disposed on a single substrate, the substrate secured to the diaphragm, the sensor array having a first outer sensor near an edge of the diaphragm at a first location and on the active region, a second outer sensor near an edge of the diaphragm at a second location and on the active region, and at least one center sensor substantially overlying a center of the diaphragm, the sensors connected in a bridge array to provide an output voltage proportional to the force applied to the diaphragm. The sensors are dielectrically isolated from the substrate.

Abstract: A sensor array for a pressure transducer having a diaphragm with an active region, and capable of deflecting when a force is applied to the diaphragm. The sensor array disposed on a single substrate, the substrate secured to the diaphragm. The sensor array having a first outer sensor near an edge of the diaphragm at a first location and on the active region, a second outer sensor near an edge of the diaphragm at a second location and on the active region, and at least one center sensor substantially overlying a center of the diaphragm. The sensors connected in a bridge array to provide an output voltage proportional to the force applied to the diaphragm. The sensors dielectrically isolated from the substrate.

Abstract: A pressure sensor header for a pressure transducer includes a header shell having a sensor cavity formed therein, a sensor element disposed in the sensor cavity, a fluid medium disposed in the sensor cavity, an isolation diaphragm closing the sensor cavity, and a joining arrangement disposed at an interface of the isolation diaphragm and the header shell, the joining arrangement joining the isolation diaphragm with the header shell. The isolation diaphragm is an integral unit comprising a thin membrane surrounded by a thicker outer ring. The joining arrangement has a recessed female joining element formed in one of the outer ring of the isolation diaphragm and the header shell, and a protruding male joining element formed on the other one of the outer ring of the isolation diaphragm and the header shell, the male joining element received in the female joining element.

Abstract: A pressure transducer assembly including: a pressure sensor header; a transducer assembly member; and a joining arrangement disposed at an interface of the header and the transducer assembly member, for joining the header with the transducer assembly member, the joining arrangement including: a recessed female joining element formed in one of the header and the transducer assembly member; and a protruding male joining element formed on the other of the header and the transducer assembly member, the male joining element received in the female joining element.

Abstract: A pressure sensor header for a pressure transducer includes a header shell having a sensor cavity formed therein, a sensor element disposed in the sensor cavity, a fluid medium disposed in the sensor cavity, an isolation diaphragm closing the sensor cavity, and a joining arrangement disposed at an interface of the isolation diaphragm and the header shell, the joining arrangement joining the isolation diaphragm with the header shell. The isolation diaphragm is an integral unit comprising a thin membrane surrounded by a thicker outer ring. The joining arrangement has a recessed female joining element formed in one of the outer ring of the isolation diaphragm and the header shell, and a protruding male joining element formed on the other one of the outer ring of the isolation diaphragm and the header shell, the male joining element received in the female joining element.

Abstract: A pressure sensor 11 is provided with a connecter housing 30 having a pressure sensing element 20 arranged on an end surface thereof, a sensor housing 40 constructed to have the connecter housing 30 inserted thereinto, a pressure chamber 452 defined between the end surface of the connecter housing 30 and the sensor housing 40, and a compensation circuit 21 for performing the processing and operation of a measured signal of the pressure sensing element 20 to output the measured signal.

Abstract: A device for monitoring the filling of a bag (10) comprises a resistor element to be mounted on the outside surface of the bag, the resistor element being a flexible potentiometer (20), the resistance whereof being changed by bending of the potentiometer due to increasing bulging of the bag wall under continuing filling of the bag. The flexible potentiometer can be connected to an alarm device (24) reacting at a predetermined resistance value of the resistor element.

Abstract: A transducer packaging assembly for use in a sensing unit subjected to high forces of acceleration includes a base having a cavity. A pressure sensitive semiconductor die is bonded to a large backplate having a shape so that it nestles into the cavity but is spaced from a surface of the cavity. A planar cover secured to the base has a hole larger than the die but smaller than the backplate, and thin wires extend from the die to electrical connections on the assembly. A viscous fluid fills a space between the backplate and the cavity, and a space between the backplate and the cover, and transmits a pressure to be measured to the pressure sensitive die. The viscous fluid has a sufficiently high viscosity to oppose movement of the backplate relative to the cavity while cushioning the pressure sensitive die and the backplate from forces of acceleration.

Abstract: A semiconductor component is fashioned of a chip carrier comprising an approximately planar chip carrier surface on which chip carrier surface a semiconductor chip with a pressure sensor is secured, and composed of electrode terminals penetrating the chip carrier and electrically connected to the semiconductor chip, with a surface-mounted arrangement. The chip overlapping the chip carrier.

Abstract: A protective construction for a piezo-resistive silicon pressure transducer intended for connection to a pressure source that exhibits pressure transients. The construction includes the transducer, a conduit for providing pressure communication between the pressure source and the transducer and a flow restrictive device positioned within the conduit.

Abstract: The invention relates to a method of producing a pressure sensor component with a chip carrier which has a substantially planar chip carrier surface and a semiconductor chip with an integrated pressure sensor on the chip carrier surface.

Abstract: A semiconductor device die comprising one or more stress-isolated regions is described. In one embodiment, stress isolation is achieved by providing a nominally rigid rim region which forms part of the stress isolated region. The rim region is attached to a nominally rigid periphery or frame region by a flexible, spring-like stress-isolation region such that displacements and twisting of the frame region due to mounting and packaging stresses are mitigated, do not propagate to the stress-isolated region, and do not effect the output signal. The stress isolation flexible region includes first and second members etched from the semiconductor device material to mechanically isolate the diaphragm from its periphery. The first member is formed by etching a first deep trench. The combination of the first deep trench etch and a second deep trench etch define the second member. In one embodiment, the stress-isolated region comprises a pressure-sensitive deformable diaphragm for sensing pressure.

Abstract: A semiconductor composite sensor using a plurality of semiconductor piezoresistive gauge elements connected in series. The piezoresistive elements are separated so that a high potential terminal of one of the resistive elements having the same resistance values and the substrate of the other of the resistive elements will be connected with equal potential values. Potential difference values between semiconductor regions serving as respective resistive elements and the substrates are made equal.

Abstract: The pressure sensor component has a chip carrier with an approximately planar chip carrier surface. A semiconductor chip with an integrated pressure sensor is placed on the chip carrier surface. A pressure-detecting surface area of the pressure sensor is exposed to a pressure to be measured. The component is encapsulated with electrically insulating material that encloses the semiconductor chip and/or the chip carrier at least in regions. A chimney-shaped connection piece that projects up relative to the pressure-detecting area of the pressure sensor penetrates through the encapsulation and is connected to the pressure sensor. The connection piece, which is a separate structural element is incorporated in the component encapsulation and it encloses at least the pressure-detecting surface area in a pressure-tight manner with its end bearing on the semiconductor chip. The connection piece is open toward the outside at its opposite end so as to expose the pressure sensor to the pressure to be measured.

Abstract: A pressure transducer which has a housing containing a sensing element and a noncorrosive fluid in contact with the sensing element. A porous material isolates the fluid from a harsh liquid or a liquid containing solids while allowing transmission of the pressure of the liquid.

Abstract: A pressure transducer employing a metal isolation diaphragm. A volume of oil is located between the metal diaphragm and a silicon sensor received in a base member. In order to reduce errors at very low pressure caused by the oil exerting a tension on the deflecting portion of said silicon sensor, the metal diaphragm has an extending dome or dimple above the location of the silicon sensor. The silicon sensor is also recessed below the supporting base plate so that the separation between the silicon sensor and the metal diaphragm increases. The base plate also contains a series of shallow, narrow concentric grooves which further reduces surface tension between the metal diaphragm and the base plate.

Abstract: A semiconductor sensor device including a semiconductor diaphragm member having a top surface coated with an oxide layer; P+ sensor elements fusion bonded to the oxide layer at a relatively central area of the diaphragm; P+ finger elements fusion bonded to the oxide layer extending from the sensors to an outer contact location of the diaphragm for each finger; and an external rim of P+ material fusion bonded to the oxide layer and surrounding the sensors and fingers. A first glass wafer member is electrostatically bonded at a bottom surface to the fingers and rim to hermetically seal the sensors and fingers of the diaphragm member. The first glass wafer includes a depression above the sensors and has a plurality of apertures, where each aperture is associated with a separate finger at the contact location and each aperture being smaller than the associated finger lining up with the contact location wherein each contact location can be accessed via the associated aperture in the first glass wafer member.

Abstract: A reduced size, hermetically sealed semiconductor transducer and methods for fabricating the same. In a preferred embodiment, the transducer comprises a transducer wafer including a diaphragm which deflects upon the application of a force thereto. At least one semiconductor transducer element and one electrical contact are disposed on a top surface of the transducer wafer, with the electrical contact coupled to the semiconductor element and extending to a peripheral portion of the wafer. A cover member is provided that is dimensioned to surround the semiconductor element. A peripheral glass frit bond is formed between the cover member and the transducer wafer, and between the cover member and at least a portion of the electrical contact. An aperture is formed in a top portion of the cover member, positioned above a region bounded by the peripheral glass bond. This aperture functions to prevent air gap formation in the peripheral glass frit bond.

Abstract: An improved resistor and connection region structure in which the geometries of the connection regions for a pair of radial resistors correspond to the connection region geometries for a pair of tangential resistors, thus inherently eliminating the need for varying connection regions to compensate for offset. In particular, the radial resistors are formed by placing two legs in parallel with each other and connecting those legs in series on opposite sides of the membrane, with the connection region on the interior of the membrane. The tangential resistors, on the other hand, are formed on the opposite sides by placing two legs in series with each other and connecting those legs in series, with an interior connection region connecting them.

Abstract: Disclosed is the method of producing a piezo-device utilizing an ultra-thin Mo-C film as a piezoresistive material for a general class of improved piezo-device with the high sensitivity and the weak temperature dependence.

Abstract: A pressure transducer has a cylindrical body with a thread formed on at least part of the outer surface. A resistance element is wound in the thread and an internal bore receives pressurized fluid. The resistance element is strained by application of pressure to vary its resistance.

Abstract: A high pressure sensor structure (11, 111, 211) includes a housing (12, 112, 212) having an upper cavity portion (13, 113, 213) and a lower cavity portion (16, 116, 216). A diaphragm (18, 118, 218) separates the upper cavity portion (13, 113, 213) from the lower cavity portion (16, 116, 216). A semiconductor chip (26, 126, 226) is attached to the upper surface of the diaphragm (18, 118, 218) within the upper cavity portion (13, 113, 213). The diaphragm (18, 118, 218) has a thickness (21, 121, 221) and an exposed width (23, 123, 223) such that the semiconductor chip (26, 126, 226) generates a measurable output signal when the lower surface of the diaphragm (18, 118, 218) is exposed to a high pressure environment.

Abstract: An improved carbon-free force sensitive ink for a force sensor. The ink when deposited and dried can function at temperatures of up to 350.degree. F. and pressures of up to 10,000 psi. The preferred ink includes a thermoplastic polyimide binder, conductive particles, intrinsically semi-conductive particles, and dielectric particles, all of an average particle size of 1.0 micron or less. The preferred semi-conductive particles are molybdenum disulfide, ferric and ferrous oxide particles. The preferred conductive particles are conductive metal oxide compounds that deviate from stoichiometry based on an oxygen value of two, such as conductive tin oxide, Fe.sub.3 O.sub.4 iron oxide, and mixtures of them. The preferred dielectric particles are silica. The binder is present in an amount of 20 to 80% by volume. The sensor and a method of making the sensor are also disclosed.

Abstract: A pressure sensor die is provided with a flexible membrane and a plunger which combine to amplify a low pressure signal while also providing media isolation between a fluid being measured and the internal components of a pressure sensor. One embodiment of the pressure sensor disposes an end of the plunger in direct contact with a pressure sensor die while another embodiment disposes an elastomeric diaphragm between the plunger and the pressure sensor die. This second embodiment creates a chamber between the plunger and the pressure sensor die in which a fluid is captured by movement of the plunger. The captured fluid is decreased in volume by movement of the plunger and the resulting increase in pressure in transmitted to a pressure sensitive portion of a pressure sensor die. The device is particularly useful in conjunction with applications where media isolation is required between the fluid being measured and the components of the pressure sensor, such as kidney dialysis machines.

Abstract: A force sensor is provided which incorporates a pressure transducer disposed within a housing structure. A force transmitting means, such as a shaft slidable within an opening, is provided to communicate force from an external source to a diaphragm of a pressure sensor. An elastomeric conductor is disposed between electronic components on the diaphragm of a pressure sensor die and conductive leads that are used to communicate signals from the pressure sensor die to components external to the present invention. In certain preferred embodiments, the present invention provides a preselected quantity of resilient material between a first end of the slidable shaft and the diaphragm of the pressure sensor die. Other embodiments place the first end of the shaft in direct contact with the diaphragm.

Abstract: A semiconductor strain sensor includes a silicon substrate, a strain resistive element and electrodes. The silicon substrate has a deformable portion which is deformed when stress is applied to it. The strain resistive element is formed on the deformable portion and has an at least a first layer and a second layer which form a heterojunction between them. The first layer is doped with impurities so that a two-dimensional carrier gas layer is formed in the second layer near the heterojunction. The two-dimensional carrier gas layer has carriers originating from the impurities. The electrodes electrically contact the two dimensional carrier gas layer. Change of resistance of the strain resistive element in accordance with the stress is detected through the electrodes.

Abstract: A pressure transducer for measuring high differential pressure media in a harsh environment where a diaphragm assembly is mounted to an intermediate support number which is mounted to a main support member where the high pressure media impinges on the diaphragm to create a force opposing that provided by the diaphragm support structure thereby loading the diaphragm in compression. The strain sensitive piezoresistive elements are protected and sealed from the low pressure media by a passivation layer and electrical signal leads are attached to bonding pads formed on the diaphragm assembly which are sealed to the intermediate support member by a sealing cap.

Abstract: A signaling gauge may utilize a magnetically actuated variable resistor made up of a plurality of noncaptivating, magnetically actuated switch elements, each of which is mounted in an influence zone of a path of a magnet carried on an arm of a condition sensor such as a gauge movement. The arm may be an indicating pointer of the gauge. The gauge may alternatively utilize a magnetically-sensitive, variable-resistance element in a contactless arrangement with a magnet. The variable resistance element may include a plurality of noncaptivating, magnetically actuated switch elements and associated resistors mounted in an influence zone of a path of a magnet. The contactless arrangement eliminates the need for electromechanical contacts.

Abstract: The present invention provides a vacuum gauge having two integrated circuits connected in a half bridge circuit to register subatmospheric gas pressure from a change in thermal gas conductivity. One of the integrated circuits serves to generate an electrical current proportional to the ambient temperature and a function of its power output conducted by the gas. The other of the integrated circuits acts as a reference to generate an electrical current proportional to ambient temperature. The half bridge circuit acts to subtract the currents so that subatmospheric pressure can be read on an ammeter as a function of gas thermal conductivity.

Abstract: A stress sensor for detecting a stress, including a ceramic hollow member, a pair of support members for supporting the ceramic hollow member, and at least one resistor provided on the ceramic hollow member. The ceramic hollow member is deformable according to a stress applied thereto in a direction in which a hollow of the hollow member extends. The support members are disposed at opposite ends of the hollow member, so as to support the hollow member such that the stress is imparted to the hollow member through the pair of support members. The resistor or resistors is/are disposed on one of the inner and outer surfaces of the hollow member. The stress is detected based on a change in the electrical resistance value of the resistor or resistors which is caused by the deformation of the hollow member.

Abstract: A precision pressure sensor in the form of a load cell has a mounting ring closed at one end by an end wall which has axially outwardly facing dead-end holes therein to form sensor beams each having an axially outwardly facing plane surface to which strain gages are bonded. The dead-end holes have bottoms forming sensor membranes. Opposite the closed end the mounting ring encloses a cavity forming a sensor space which is closed by a closure plug that simultaneously has a bore for admitting fluid under pressure to be measured into the sensor space. A ring groove in the end wall has approximately radially sloping surfaces which together with the dead-end holes determine the minimum cross-section of the measuring beams. The ring groove also determines the minimum thickness of the sensor membranes.

Abstract: A pressure sensor that utilizes an extension type conductive elastomer that will exhibit a decrease in its electrical resistance in response to an extension thereto. Like sheets of the conductive elastomer and an electrically insulative elastomer are overlaid and sandwiched between supporting members within a housing of the pressure sensor. The housing and each supporting member are preferably cylindrical or ring shaped, and which conductive elastomer has a pair of spaced electrodes electrically connected thereto at opposite points on its periphery. The periphery of the electrically insulative elastomer is squeezed continuously in a circle between the supporting members, while that of the conductive elastomer that includes recesses is squeezed therebetween discontinuously in the sections between the electrodes.

Abstract: A hydraulic actuating apparatus includes a cylindrical case having a fitting at one end connectable to a source of pressurized oil, the fitting having a passage for communication with the pressurized oil, a slider slidably carried by the cylindrical case, the slider being slidable in response to the oil pressure, a first spring device for biasing the slider in a predetermined direction to resist the force on the slider applied by the oil pressure, a slidable contact device carried by the slider, an oil pressure sensor which includes a resistor and a ground conductor, the slidable contact device being slidably engaged with the resistor, the resistor being fixed with respect to the slidable contact device, and a second spring device for biasing the slider in the predetermined direction. The second spring device is connected to the slider, with the second spring device having a smaller spring constant than the first spring device.

Abstract: A hydraulic actuating apparatus for sensing hydraulic pressure and producing an output signal representative of the sensed hydraulic pressure includes a base portion, a case, and a variable resistor unit. A slider is movably connected to the variable resistor unit, and the variable resistor unit is connected to the base, the slider being movable relative to the variable resistor unit by an amount proportional to the hydraulic pressure applied to the slider. The variable resistor unit has a resistance which changes in response to movement of the slider. A resilient member is provided which is resiliently deformable by movement of the slider relative to the variable resistor unit, the resilient means exerting a restoring force on the slider opposing the movement of the slider caused by the hydraulic pressure. An adjusting mechanism is provided for setting an initial resistance value of the variable resistor unit, the variable resistor unit having a portion which is in contact with the adjusting mechanism.

Abstract: The marginal adhesion of platinum to silicon nitride is a serious issue in the fabrication of microbridge mass air flow sensors. High temperature stabilization anneals (500.degree.-1000.degree. C.) are necessary to develop the properties and stability necessary for effective device operation. However, the annealing process results in a significant reduction in the already poor platinum/silicon nitride adhesion. Annealing at relatively high temperatures leads to the development of numerous structural defects and the production of non-uniform and variable sensor resistance values. The use of a thin metal oxide adhesion Layvr, approximately 20 To 100 angstromw in thickness is very effective in maintaining platinum adhesion to silicon nitride, and through the high temperature anneal sequence.

Abstract: A pressure sender is provided with a variable electrical resistance corresponding to a sensed pressure, to be placed in series with a voltage source and a pressure gauge. The pressure sender is diaphragm-actuated, which diaphragm controls the positioning of an electrical contact against a ceramic thick film rheostat. An electrically conductive metal clip secures the rheostat in position as well as completes the electrical connection between the rheostat and the electrical circuit of which the pressure sender is a part. The electrical contact is rockingly mounted so that deflection of the diaphragm displaces the electrical contact through an arcuate travel path along various resistance positions of the thick film ceramic rheostat. Current from the electrical circuit will flow through the metal clip to input contacts of the rheostat, and then to the resistance positions.