Abstract: There is disclosed a header for a differential pressure transducer. The header has a cylindrical sensor housing section which has a front and a back surface. The front surface has a sensor accommodating recess. There is a plurality of terminal pins extending from the front surface and directed through the housing to extend from said back surface. The pins are arranged in a semi-circular pattern, said sensor housing having a stem aperture and cylindrical wall. A stem housing is positioned in the stem aperture and is brazed thereto. The stem housing has a stem passageway directed through the housing which communicates with a passageway in the cylindrical sensor housing. The cylindrical sensor recess contains a sensing device which receives a first input pressure on one diaphragm surface of the sensing device and a second input pressure on a second surface of the diaphragm to produce a differential output pressure. The header, as indicated, is rugged and simple to use and produce.

Abstract: There is disclosed a high pressure sensing header which is relatively insensitive to mounting torque. Essentially the header consists of an outer torque isolating shell which has a “C” shaped cross section with the cylindrical shell surrounding an inner “H” section header. The inner “H” section header has a thick diaphragm and is surrounded by the torque isolating shell which is secured to the “H” section header at a peripheral flange of the “H” section header. In this manner when the header is installed, the installation force is absorbed by the outer shell and there is no installation force or torque exhibited by the inner “H” section which will respond only to stress due to pressure. The torque isolating shell also contains a top surface which has a counterbore which can accommodate a crush ring, and when the unit is installed, the crush ring is forced or crushed against an installation wall to enable the inner header to receive pressure without experiencing any significant installation force.

Abstract: A semiconductor filter is provided to operate in conjunction with a differential pressure transducer. The filter receives a high and very low frequency static pressure attendant with a high frequency low dynamic pressure at one end, the filter operates to filter said high frequency dynamic pressure to provide only the static pressure at the other filter end. A differential transducer receives both dynamic and static pressure at one input port and receives said filtered static pressure at the other port where said transducer provides an output solely indicative of dynamic pressure. The filter in one embodiment has a series of etched channels directed from an input end to an output end. The channels are etched pores of extremely small diameter and operate to attenuate or filter the dynamic pressure.

Abstract: A joystick apparatus employs a hermetically sealed load cell having strain gauges placed on flexible beams formed on the load cell. All of the strain gauges are on the same surface of the load cell and therefore wiring is performed on a single side of the load cell. The strain gauges are enclosed in hermetically sealed cavity. The sensing diaphragm consists of a concentric thick inner and outer section joined by thinner diametrically opposed beam elements. The thin beam elements are compliant members which can deflect. Each beam includes strain gauges or sensor elements and the load cell is coupled to a joystick which when moved causes the beams to deflect to cause the sensor elements to produce an electrical output proportional to the force and direction of the joystick. The sensor can yield an output proportional to any angle over the 360° movement of the joystick to provide outputs proportional to the X and Y positions of said joystick.

Abstract: A high temperature pressure transducer is fabricated from silicon carbide. A wafer of silicon carbide has reduced or active areas which act as deflecting diaphragms. Positioned on the reduced or active area is a silicon carbide sensor. The sensor is secured to the silicon carbide wafer by a glass bond. The pressure transducer is fabricated by first epitaxially growing a layer of highly N-doped 3C silicon carbide on a first silicon wafer or substrate. A second wafer of silicon carbide is selected to be a carrier wafer. The carrier wafer is etched preferentially to produce the deflecting members or reduced areas which serve as diaphragms. The 3C material on the silicon slice is patterned appropriately to provide a series of individual piezoresistors which then may be interconnected to form a Wheatstone bridge.

Abstract: An oil filled pressure transducer which exhibits reduced backpressure and utilizes a smaller volume of oil employs a glass pre-form which has a plurality of pin accommodating apertures and has an oil tube accommodating aperture. There are a plurality of contact pins inserted into the pin accommodating apertures and which extend from the top to the bottom surfaces of the pre-form. There is an oil fill tube inserted into the oil tube accommodating aperture, which oil fill tube extends from the bottom to the top surface of the pre-form with one end of the tube extending above the top surface of the pre-form. There is a glass alignment plate which has an alignment aperture for encircling the extended oil fill tube and has a sensor accommodating shaped aperture located at a predetermined position from said alignment aperture.

Abstract: There is disclosed flat planar pressure transducer which comprises a planar insulative substrate of a rectangular configuration. Disposed on the substrate is an array of conductive areas which extend from a contact terminal area of said substrate to an end of the substrate. There is a leadless sensor module positioned at said contact terminal area, with the contacts of said leadless sensor contacting contact terminals of said contact terminal area. The leadless sensor is enclosed by an enclosure which is coupled to the substrate and surrounds the sensor. The enclosure has a screen positioned on the top surface to prevent particles from entering or damaging the leadless sensor. The above-noted structure forms a very flat, compact pressure transducer which can be utilized in lieu of flex circuit type devices and provides greater mechanical stability as well as a more accurate output.

Abstract: There is disclosed an internally switched multiple range transducer. The transducer employs a plurality of individual pressure sensors or Wheatstone bridges fabricated from semiconductor materials and utilizing piezoresistors. Each sensor is designed to accommodate accurately a given pressure range, therefore, each sensor is selected to provide an output when an applied pressure is within its accommodated range. As soon as the pressure exceeds the range, then another sensor is employed to produce an output. Each of the sensors, or each separate transducer, is coupled to a switch or other device to enable the selection of one of the plurality of sensors to operate within its given pressure range when the applied pressure is in that range. In this manner one obtains pressure measurements with a high degree of accuracy across a relatively large pressure range.

Abstract: A combined wet-wet differential transducer and a gage pressure transducer located in the same housing, comprising a semiconductor chip which comprises a gage sensor chip on one section and a differential sensor chip on a second section. Each sensor chip has a Wheatstone bridge comprising piezoresistors and is responsive to an applied pressure. The gage chip and the differential chip are placed in a header having a front section and a back section adapted to receive a first and second pressure, respectively. The sensors are in communication with first and second pressure ports such that the absolute sensor provides an output indicative of a pressure applied to a first port and the differential sensor provides an output indicative of the pressure difference between the first and second pressure ports.

Abstract: A pressure transducer, particularly adapted to measure the pressure in a tire and to enable the tire to be filled includes a first housing, having an internal hollow. Positioned in the hollow of the first housing is a second housing, also having an internal hollow. The second housing is supported within the first housing so that a passageway for airflow exists between the housings. The second housing has a pressure port for monitoring the pressure of a tire. The first housing has an inlet port for receiving a source of pressure. The inlet port contains a valve which is selectively operated. The valve, when operated, permits air to flow into the hollow of the first housing and to flow about the periphery of the second housing to enter the pressure port associated with the second housing. The pressure port may, as indicated, be associated with a tire and the second housing contains a pressure sensing device which monitors the pressure in the tire via the pressure port.

Abstract: There is disclosed an apparatus for measuring multiple pressures within different pressure ranges. The apparatus contains multiple pressure sensors which are positioned on a housing, where each pressure sensor is adapted to measure pressure within a different pressure range. The housing has an input port which is constructed to communicate with different output ports, where the output ports communicate with each different pressure sensor utilized in a different pressure range. The input port has a stepped or keyed aperture which is adapted to receive different pressure adapters. The input port enables the selective insertion of various pressure adapter members as indicated where each pressure adapter member can only be inserted within the input port to a desired position, where at that position, the pressure applied to the input port will be directed to the proper pressure sensor.

Abstract: A combined wet-wet differential transducer and a gage pressure transducer located in the same housing, comprising a semiconductor chip which comprises a gage sensor chip on one section and a differential sensor chip on a second section. Lach sensor chip has a Wheatstone bridge comprising piezoresistors and is responsive to an applied pressure. The gage chip and the differential chip are placed in a header having a front section and a back section adapted to receive a first and second pressure, respectively. A central section adjoins the front and back sections to form an H shaped header. The sensors are in communication with first and second pressure ports such that the absolute sensor provides an output indicative of a pressure applied to a first port and the differential sensor provides an output indicative of the pressure difference between the first and second pressure ports.

Abstract: There is disclosed a transducer employing radiation hardened electronics. Essentially a sensor assembly is positioned in a front section of a housing where the sensor assembly is coupled to an electronic module via terminals which connect the sensor to the module. The electronic module assembly is surrounded by an internal tungsten housing which is formed from a first tungsten “U” shaped cross-sectional member coupled to a second tungsten “U” shaped cross-sectional enclosure. The two members are coupled together and totally surround the electronic assembly. The members as held together are positioned within the housing by outer shell members to form a complete housing assembly whereby the electronic assembly and its associated terminal pins are totally surrounded by the tungsten holder section and the tungsten enclosure section.

Abstract: There is described a temperature compensation scheme for a pressure sensitive metal diaphragm transducer. The transducer employs a Wheatstone bridge fabricated from p-type piezoresistors. The Wheatstone bridge is glassed directly onto the metal diaphragm. As the temperature of operation increases, the diaphragm exhibits a temperature variation of the Modulus of Elasticity. The Modulus of the metal diaphragm decreases with increasing temperature. Because of this, the same pressure applied to the metal diaphragm causes it to deflect further, which in turns causes increased strain applied to the bridge. Because of this effect, the sensitivity of the transducer increases with increasing temperature. A resistor is now placed in series with the Wheatstone bridge. The resistor is in series with the biasing voltage and because the TCS of the diaphragm is of an opposite sign, the series resistor has an even higher TCR in series with the bridge.

Abstract: A method of fabricating a semiconductor-on-insulator device including: providing a first semiconductor wafer having an about 500 angstrom thick oxide layer thereover; etching the first semiconductor wafer to raise a pattern therein; doping the raised pattern of the first semiconductor wafer through the about 500 angstrom thick oxide layer; providing a second semiconductor wafer having an oxide thereover; and, bonding the first semiconductor wafer oxide to the second semiconductor wafer oxide at an elevated temperature.

Abstract: A pressure header assembly has a closed front and back surface. The back surface has an aperture for accommodating a separate dual die pressure header. The dual die pressure header has an absolute and differential pressure sensor positioned thereon. A differential pressure port is located on a side surface of the pressure header assembly and is directed to a bore in the pressure header assembly. The bore contains an elongated tube which is positioned in the pressure header assembly and locked in place by means of a crush nut and locking nut assembly. One end of the tube is coupled to the differential pressure port, while the other end of the tube accommodates a differential pressure tube which is bent in an arcuate position and directed to the underside of the sensor of the differential sensor assembly mounted in the dual die pressure header.

Abstract: A system for measuring a multiplicity of pressures as those experienced by a model in a wind tunnel is depicted. The system includes individual sensor devices which are connected to an Acquisition and Compensation electronics module. The individual sensor or transducer devices are semiconductor piezoresistive devices and are connected to the Acquisition and Compensation electronics module by means of a cable in a first embodiment. In an alternate embodiment the system uses connectors which connect each of the individual sensor devices to the Acquisition and Compensation electronics module via a mating connector located therein. The connectors may also include a memory which stores compensation coefficients associated with each of the various sensor devices. In this manner as described, the transducers which are small devices are connected via electrical lines or cables to the central Acquisition and Compensation electronics modules.

Abstract: It is an objective of the present invention to provide a pressure transducer assembly for measuring pressures in high temperature environments that employs an elongated tube which is terminated at one end by an acoustic micro-filter. The micro-filter has a plurality of apertures extending from one end to the other end, each aperture is of a small diameter as compared to the diameter of the transducer and the damper operates to absorb acoustic waves impinging on it with limited or no reflection. To improve the absorption of acoustic waves, the elongated tube may be tapered and/or mounted to a support block and further convoluted to reduce the overall size and mass of the device. A pressure transducer with a diaphragm flush may be mounted to the elongated tube and extend through to the inner wall of the tube. Hot gases propagate through the elongated tube and their corresponding pressures are measured by the transducer.

Abstract: There is disclosed apparatus for measuring multiple pressures within different pressure ranges. The apparatus contains multiple pressure sensors which are positioned on a housing, where each pressure sensor is adapted to measure pressure within a different pressure range. The housing has an input port which is constructed to communicate with different output ports, where the output ports communicate with each different pressure sensor utilized in a different pressure range. The input port has a stepped or keyed aperture which is adapted to receive different pressure adapters to assure that, for example, only a high pressure will be applied to the high pressure sensor during high pressure measurements. By selecting another adapter, a mid-range pressure and a high pressure will be applied to the pressure sensors during the measurement of a mid-range pressure. By receiving a different adapter, a low pressure will be applied to all the pressure sensors during low pressure measurement.

Abstract: A pressure transducer has an H-shaped header having a front and a back section. The front and back sections are of equal diameter and are circular. Each front and back section has a depression with a diaphragm covering the depression. Each diaphragm is of equal size and the depressions communicate one with the other via a central channel in the central arm of the H. A pressure sensor communicates with the channel, where the pressure sensor responds to a first pressure applied to the first diaphragm and a second pressure applied to the second diaphragm. The pressure sensor produces an output equal to the difference in pressure. The differential pressure inducer having both diaphragms of the same size and still enabling leads from the sensor to be brought out.