Abstract: A pressure transducer using a ceramic diaphragm which is not easily damaged so that there is no risk of leakage of a target medium to be measured, having a superior mass-production capability and a reduced volume and enabling low-price by simplifying a flexible cable and a printed circuit board (PCB) to connect the transducer and a signal processing chip. The pressure transducer includes the ceramic diaphragm formed as a rectangular planar ceramic diaphragm and having a surface having formed thereon a pattern made of an electrically conductive material and strain gages; a base plate configured to face the surface of the ceramic diaphragm having formed thereon the pattern; and an adhesive layer configured to be formed along edges of a contacting surface of the ceramic diaphragm and the base plate so as to bond the ceramic diaphragm and the base plate and form a space for the strain gages.

Abstract: A technique for measuring vapor pressure and liquid level of a volatile liquid contained in a tank. An integrated measuring apparatus sequentially measures vapor pressure and differential pressure by use of a single pressure sensor and a switching valve which switches between paths for measurement of the vapor pressure and the differential pressure. In addition, the integrated measuring apparatus includes a pressure sensor configured to sequentially measure vapor pressure and total pressure or the combination of the vapor pressure and liquid pressure; and a switching valve configured to be connected to a vapor pressure tube and a liquid pressure tube and switch between connection paths with at least one input port of the pressure sensor, wherein the vapor pressure tube is connected to an upper part of the tank and the liquid pressure tube is connected to a lower part of the tank.

Abstract: An output specification calibrating apparatus for a capacitive pressure sensor. The output specification calibrating apparatus enables adjustment of non-linearity, offset, and gain of the capacitive pressure sensor in a software manner at the time of shipment. Accordingly, it is feasible to easily adjust output specifications of the capacitive pressure sensor and to thereby meet various needs of customers.

Abstract: A pressure transducer using a ceramic diaphragm which is not easily damaged so that there is no risk of leakage of a target medium to be measured, having a superior mass-production capability and a reduced volume and enabling low-price by simplifying a flexible cable and a printed circuit board (PCB) to connect the transducer and a signal processing chip. The pressure transducer includes the ceramic diaphragm formed as a rectangular planar ceramic diaphragm and having a surface having formed thereon a pattern made of an electrically conductive material and strain gages; a base plate configured to face the surface of the ceramic diaphragm having formed thereon the pattern; and an adhesive layer configured to be formed along edges of a contacting surface of the ceramic diaphragm and the base plate so as to bond the ceramic diaphragm and the base plate and form a space for the strain gages.

Abstract: A pressure sensor system involves a semi-conductive diaphragm electrode overlying a cavity in a semiconductor chip, with the center of the diaphragm secured to a mesa extending upwardly from the cavity. A second electrode is implemented by a heavily doped raised ring between the mesa and the periphery of the chip at the ring of maximum deflection of the diaphragm. The raised ring electrode is heavily doped with one polarity, with light doping near the base of the raised area, and the remainder of the cavity is heavily doped with the opposite polarity. The plot of Linearity Error versus width of the ring electrode, has a minimum, and the width of the ring electrode and related constructional features are selected to conform to the minimum point of the linearity function. The reference capacitor is arcuate in configuration and extends part way around and in immediate proximity to the sensor diaphragm.

Abstract: A highly efficient position or liquid level sensing system includes a central fluorescent fiber or rod, a transparent support for mounting the fluorescent fiber preferably in a liquid container or tank, and a float or other movable member extending around the fluorescent fiber for movement relative to the fiber. Light is directed from one end of the fluorescent fiber parallel to and around the fiber; and the side of the float or movable member facing the light reflects the incident light inward toward the fluorescent fiber. A first detector receives radiation from one end of the fiber. Detectors may be provided at both ends of the fiber, and the two outputs may be combined sustractively to provide a substantially linear signal output relative to the position of the float or movable member.

Abstract: A stabilized fluid conductivity measurement system includes a threaded metal housing with an inner portion having two probes for contacting the fluid to be measured and having an outer portion in which electrical circuitry is mounted. The circuitry includes a balanced square wave generator providing excitation to a modified Wheatstone bridge, including first and second input excitation terminals, and first and second output terminals. Fixed resistances may be located in 3 arms of the Wheatstone bridge, and the fourth arm may have two resistances with an intermediate tap; and one of the two probes is connected to this tap while the other probe is connected to one of the input excitation points.

Abstract: A stabilized fluid conductivity measurement system includes a threaded metal housing with an inner portion having two probes for contacting the fluid to be measured and having an outer portion in which electrical circuitry is mounted. The circuitry includes a balanced square wave generator providing excitation to a modified Wheatstone bridge, including first and second input excitation terminals, and first and second output terminals. Fixed resistances may be located in 3 arms of the Wheatstone bridge, and the fourth arm may have two resistances with an intermediate tap; and one of the two probes is connected to this tap while the other probe is connected to one of the input excitation points.

Abstract: A corrosion proof pressure transducer for measuring exhaust gas pressure includes a chip with a semiconductive diaphragm, electronics, and conductive pads thereon; with leads sonically bonded to the pads. To preclude degradation of the transducer by internal combustion engine exhaust gases, the chip may have (1) a thin glass passivation layer, (2) a vacuum deposited polymeric coating and (3) a layer of gel, thereon.

Abstract: An assembly for sensing the dielectric constant of liquids, and for detecting contamination, includes a central ceramic chip with a sensing capacitor formed on one end thereof and a signal processing circuit on the other end thereof. The capacitor is formed of two sets of closely spaced conductive lines or pathways with one set being grounded and the other set providing the variable output from the capacitor to the signal processing circuit.

Abstract: A combined oil quality and fuel contamination sensing system includes a capacitive dielectric sensor and pressure sensing arrangements for measuring the dielectric constant of the oil and the pressure of the oil, respectively, with the oil pressure being indicative of oil viscosity and contamination. The sensors take measurements as oil flows through an internal combustion engine and provide an indication of the cause of a problem with oil in an engine. The system may also include a microcomputer and circuitry for generating an indication of dielectric constant and circuitry for generating an indication of the presence of contaminants within the engine. The system may also include an additional sensor measuring the temperature of oil within the system to adjust oil dielectric constant and viscosity indications. The capacitive dielectric sensor constitute the principal restriction in the flow path between an input high pressure sensing port and an outlet low pressure port.

Abstract: A corrosion proof pressure transducer for measuring exhaust gas pressure includes a chip with a semiconductive diaphragm, electronics, and conductive pads thereon; with leads sonically bonded to the pads. To preclude degradation of the transducer by internal combustion engine exhaust gases, the chip may have (1) a thin glass passivation layer, (2) a vacuum deposited polymeric coating and (3) a layer of gel, thereon.

Abstract: A deign method to eliminate any micro-openings in a very high pressure sensor assembly is provided. The method involves sealing an elongated silicon pressure sensor into a fitting using an alloy and glass based materials. The materials are selected so that their thermal coefficients of expansion are progressively increasing relative to the silicon sensing element. This allows strong bonding among the materials, thereby minimizing any pressure leakage.

Abstract: An assembly for sensing the dielectric constant of liquids, and for detecting contamination, includes a central ceramic chip with a sensing capacitor formed on one end thereof and a signal processing circuit on the other end thereof. The capacitor is formed of two sets of closely spaced conductive lines or pathways with one set being grounded and the other set providing the variable output from the capacitor to the signal processing circuit.

Abstract: A design method to eliminate any micro-openings in a very high pressure sensor assembly is provided. The method involves sealing an elongated silicon pressure sensor into a fitting using an alloy and glass based materials. The materials are selected so that their thermal coefficients of expansion are progressively increasing relative to the silicon sensing element. This allows strong bonding among the materials, thereby minimizing any pressure leakage.

Abstract: A capacitive sensor is employed to measure the dielectric constant of miscible liquids, and thereby determine the relative concentration of the two liquids. Further, a feedback circuit may be provided to change the operation of the system in accordance with the relative concentration of the liquids. Further, circuit arrangements may be provided to adjust the sensitivity and offset of the electrical circuit included in the system to match the output of the sensor with the dielectric constants being measured.

Abstract: A combined oil quality and fuel contamination sensing system includes a capacitive dielectric sensor and pressure sensing arrangements for measuring the dielectric constant of the oil and the pressure of the oil, respectively, with the oil pressure being indicative of oil viscosity and contamination. The sensors take measurements as oil flows through an internal combustion engine and provide an indication of the cause of a problem with oil in an engine. The system may also include a microcomputer and circuitry for generating an indication of dielectric constant and circuitry for generating an indication of the presence of contaminants within the engine. The system may also include an additional sensor measuring the temperature of oil within the system to adjust oil dielectric constant and viscosity indications. The capacitive dielectric sensor constitute the principal restriction in the flow path between an input high pressure sensing port and an outlet low pressure port.

Abstract: A reliable capacitive oil deterioration and level sensor has a conductive housing member that includes a conductive shielding member defining a ground electrode, and a conductive inner member defining a measuring electrode. The shielding member protects the sensor from moving objects that could adversely affect its performance. The housing member is adapted to provide a fluidic connection between an oil container and a space between the ground electrode and the measuring electrode. The sensor also includes electronics adapted to employ this capacitor geometry to generate signals indicative of a degree of deterioration and a level of the oil within the gap. The electronics further include at least one isolating capacitor to eliminate a flow of current between the electrodes that may cause a build up of material on the two electrodes that define the capacitor. This build up of unwanted material may cause an undesirable effect in the sensor output signal.

Abstract: A combined mechanical linkage and force-measuring assembly includes a central capacitive force sensor, in which force applied to the sensor causes the flexing of a diaphragm toward and away from a substrate, and a change in the capacitance between two conductive surfaces on the diaphragm and the substrate is sensed and processed to indicate the direction and magnitude of the force applied to the linkage. The linkage may have two parts coupled together by a flange which flexes under applied forces, to change the spacing of the conductive surfaces.

Abstract: A capacitive pressure transducer which is shielded so that water or another fluid with a relatively high dielectric constant can be measured more accurately, as the sensor is unaffected by the relative tendency of the fluid to influence the measured capacitance, including an electrode associated with a diaphragm on a first side opposite a second, wetted, side coupled to the fluid, the diaphragm electrode being of the same or larger size than a second electrode separated therefrom by a gap, and the diaphragm electrode extending radially outward to or beyond an annular seal on or adjacent the wetted side confining fluid to an area within the outer peripheral confines of the diaphragm and within an area comprising a portion of the wetted side of the diaphragm opposite the diaphragm's electrode.