Abstract: A method using quartz resonators probes dynamically the mechanical characteristics of thin films. This method probes the film properties at the anti-resonance frequency where the vibrational amplitude is smallest, minimizing nonlinear contributions in the dependence of the film mechanical characteristics on the resonator electrical characteristics. Determination of the mechanical characteristics involves impedance analysis, transformation of .vertline.Y.vertline. and .theta. data into a linear form so that the conductance and susceptance at the frequency of minimum absolute admittance can be accurately determined, and use of a two-dimensional Newton-Raphson numerical method to determine the values of the storage modulus G', loss modulus G", as well as various other film and resonator properties.

Abstract: A plasma density monitor is described for determining the ion current of a plasma flowing through a conduit (14). The monitor comprises a plate (18) having a face and an orifice extending from the face through the plate. The internal surface of the orifice conforms with the internal surface of the conduit when the face is adjacent the conduit. The monitor also comprises a detector circuit (22) for sensing the ion current collected by the internal surface of the plate (18). Another embodiment monitors plasma density by determining electrical conductivity in the afterglow of a microwave induced plasma. A resonant LC circuit (50, C3) has a multi-turn coil (C3) surrounding the conduit, an RF oscillator circuit (54, 56) for driving the LC circuit, and a circuit (64, 66, 68, 70, 72, 76) for measuring the decay time of the LC circuit. Plasma flowing through the conduit alters the resistivity of the coil and the time constant of the LC circuit proportional to the electrical conductivity of the flowing plasma.

Abstract: Fluid transmission pipelines and similar structures which are cathodically protected from electrolytic corrosion and are disposed in urban areas under pavements and other structures which prevent access to the soil for verifying pipe-to-soil potentials are subjected to pipe-to-soil potential measurements using a reference electrode disposed in a container which has a permeable bottom and which is capable of saturating a pavement layer with a brine electrolyte to provide electrical conductivity between the reference electrode and the soil. Validation of electrical conductivity is made by a second reference electrode of a dissimilar metal which is also disposed in a container having a permeable bottom and an electrolyte which permeates the pavement layer and establishes electrical conductivity between the soil and the second reference electrode. Potential measurements between the first and second electrodes validate ion transport between the soil and the first reference electrode.

Abstract: A tactile-acoustic transducer comprises a vibrator plate, microphone means and first and second electrode members which are connected to a source of information through a tuneable network. The microphone means are coupled to a computer having display devices and a control output delivering control signals to the tuneable network. Rubbing the vibrator plate with the fingertip of his middle finger allows an operator to assess two different states of the transducer, perceived as "stick" and "non-stick" rubbing conditions, the "stick" condition being accompanied by emission of a characteristic sound and occurring when the network is tuned exactly in accordance with the phenomenon or condition of the source to be detected or measured.

Abstract: A relative volume fraction probe particularly for use in a multiphase fluid system includes two parallel conductive paths defining therebetween a sample zone within the system. A generating unit generates time varying electrical signals which are inserted into one of the two parallel conductive paths. A time domain reflectometer receives the time varying electrical signals returned by the second of the two parallel conductive paths and, responsive thereto, outputs a curve of impedance versus distance. An analysis unit then calculates the area under the curve, subtracts the calculated area from an area produced when the sample zone consists entirely of material of a first fluid phase, and divides this calculated difference by the difference between an area produced when the sample zone consists entirely of material of the first fluid phase and an area produced when the sample zone consists entirely of material of a second fluid phase. The result is the volume fraction.

Abstract: A combination and unitary corrosion monitor and reference cell for cathodic protection systems includes an elongated tubular metal element of the same material as the structure to be protected and a reference cell on one end of the tubular element, adapted to be buried or submerged in an electrolyte. The tubular element includes resistance connections along its length and a reference resistance element sealed inside. Ratiometric resistance measurements enable the extent of corrosion and corrosion rates to be determined with automatic compensation for temperature changes. Both the resistance measurements and the potential measurements from the cell may be taken from the same test station or location.

Abstract: This instrument can measure parameters of a plasma accurately and easily even though the plasma is exited by a high-frequency. The instrument for measuring parameters of a plasma generated in a vacuum chamber by high-frequency discharge at a given frequency comprises a wire (106) for electrically connecting a first electrode (101) arranged in a space where a plasma is produced and a terminal (110) arranged outside the vacuum chamber for taking out signals, and a first insulator (105) so arranged as to cover at least a part of the surface of the wire therewith. The absolute value of the impedance at the given frequency between the first electrode and the ground when looking into the terminal side from the first electrode is five times or more the absolute value of the impedance at the given frequency between the first electrode and the plasma in a state where no direct current flows through the first electrode.

Abstract: An apparatus is taught for carrying out electrochemiluminescent measurements which includes a working electrode and a temperature sensor. The electrochemiluminescent measurements made by the apparatus are adjusted based upon the measured temperature.

Abstract: A standard resistor having a known resistance value is connected to one transistor in a drive IC. The drive IC has a plurality of transistors each controlling the on/off of a heating element. The saturation voltage of each transistor is generally the same. One of a plurality of transistors is turned on, and a discharge time required for a capacitor to discharge via a standard resistor or via each heating element and lower its voltage to a predetermined voltage is measured. The resistance value of each heating element is determined from a ratio of a discharge time via each heating element to a discharge time via the standard resistor and the resistance value of the standard resistor. A difference between the standard resistance value and a resistance value of each heating element generates a bias heat energy error during bias heating and an image heat energy error during image heating. In accordance with these heat energy errors, bias data for generating a heat energy immediately before coloring is corrected.

Abstract: An apparatus and method for determining a property of a sample, derived from a response obtained from the sample after an electrical pulse has been applied to it. Blood cells are subjected to an electrical pulse, a response is obtained using data retrieval means and a Fourier Transform is applied to the response. As the pulse applied is of very short duration (ideally a Dirac pulse) the Fourier transform yields information across a very broad bandwidth, typically several MHz, and accordingly a wide range of frequency response data is obtained. Certain cellular defects can be deduced from the transformed data. A detector is provided to detect precisely the presence of a cell as it passes through a particular region of an oriface. This is then used to trigger the pulse at a precisely controlled instant. This reduces the effect of random dispersion and can be adapted to ignore noise peaks which inevitably occur.

Abstract: A method for locating the joints and fractures of underground cast iron gas mains comprises connecting several sections of an underground cast iron gas main pipeline across a sixty watt signal generator with an audio-frequency signal output of 7800 hertz. The connections take advantage of service lines, valve boxes and drip access at the surface, otherwise holes are drilled to accommodate contact probes. The signal passes through the pipe sections and their joints in series. The centerline of the underground cast iron gas main pipeline is plotted directly above on the surface of the ground, e.g., along a surface centerline. The relatively higher impedance of the pipe joints compared to the pipes themselves, causes current fluxes to radiate from each joint. The relative linear positions and their corresponding signal power measurements are collected along the surface centerline.

Abstract: This invention is related to an apparatus and method to determine the hemoglobin concentration of individual red blood cells by measuring the radio frequency resistance (RF) and direct current (DC) resistance resulting during the flow of the cells through a measurement aperture. The hemoglobin concentration of the cell is determined using the ratio of these two resistances. This determination can be made using a focused flow cell and a non-focused flow cell. In addition, the determination can be made with red blood cells which are either in their native, deformable state or with red blood cells that have been isovolumetrically sphered.

Abstract: An apparatus for detecting particles within a hydraulic system having a hydraulic line includes a capacitor formed by a pair of electrodes. A charging circuit produces a charging current of constant magnitude. The charging current is used to charge the capacitor to a predetermined voltage. A timing circuit measures the elapsed time between the time at which the charging circuit begins to produce the charging current and the time at which the capacitor has been charged to the predetermined voltage. The timing circuit produces a pulse width modulated signal. The magnitude of the pulse width modulated signal is indicative of the time difference. A controller receives the pulse width modulated signal and detects particles by comparing the duration of each pulse with a reference pulse.

Abstract: Measuring apparatus includes a first element having its impedance dependant on the state of its surroundings and a second element having a variable impedance connected to the first element. A voltage at the connection point between the first and second elements is converted into a digital value and the impedance of the second element is set based on the converted digital value. The surrounding state (e.g., humidity) is determined based on the converted digital value.

Abstract: A dual-slope measuring circuit for measuring an unknown resistance. A first time measurement measures the time which is needed to charge a capacitor to a first reference voltage (Uref.sub.1) via a reference resistor. A second time measurement measures the time which is needed to charge the capacitor again to the first reference voltage (Uref.sub.1) but now via the parallel arrangement of the reference resistor and the unknown resistance. The value of the unknown resistance is determined from the ratio between the two time intervals thus measured. The time measurement is not started until the capacitor voltage (Uc) on the capacitor has passed a second reference voltage (Uref.sub.2), where the second reference voltage has a value between the first reference voltage and the capacitor voltage (Uc) appearing across the capacitor immediately after discharge of the capacitor.

Abstract: A dielectric-loaded, microwave sensor which can detect dielectric coatings, e.g., air, water and ice, on a road surface. The sensor includes an antenna having an aperture and also includes a dielectric member with a lower surface and an upper surface. The dielectric member is arranged with its lower surface across the antenna aperture and the sensor is embedded in a road with the dielectric member's upper surface coplanar with the road's surface. An antenna beam, which is incident upon the dielectric member, generates a return microwave signal which is the composite of microwave reflections from the dielectric member's inner and outer surfaces. Air, water and ice can be uniquely identified by the absence or presence of an amplitude minimum at predetermined frequencies of the return microwave signal. The thickness of an ice coating is determined by observation of the frequency of the amplitude minimum.

Abstract: A method of verifying that a given insulative element conforms with a reference insulative element, comprising the steps of: emitting a primary beam of electrons impinging on the given insulative element, receiving a secondary beam of electrons returned by the given insulative element in response to emission of the primary beam of electrons, and comparing a curve as a function of time of the electrical current of the secondary beam received with a curve as a function of time of a reference electrical current to establish whether or not the given insulative element conforms to a reference insulative element.

Abstract: A fluid drip detection system which is not prone to false alarms caused by the presence of dirt or solid particle contaminants in the fluid. The fluid drip detector comprises; a conducting hollow housing for permitting fluid flow and passage therethrough, the housing having a first and second conducting seats. A first conducting door is urged against the first seat and a second conducting door is urged against the second seat. The first and second doors disengage from their respective seats in a drip condition and in response to fluid movement. A conducting rod is connected to one of the doors and is slidingly fitted into a bore in the other door, such that in a no drip condition, if one of the doors is disengaged from its seat by dirt, the other door can still engage its seat, and a lead connected to the housing, for producing an electrical output in the event of a drip. Such electrical output is transmitted to a timer unit that can control the fluid flow by controlling a cut off valve.

Abstract: Apparatus for measuring concentration of solid particles in a fluid stream that includes a probe for disposition in the fluid stream to provide an electrical probe signal as a triboelectric function of concentration of solid particles in the fluid stream. A first circuit is coupled to the probe for providing a first electrical signal as a proportional function of the probe signal. A second circuit is coupled to the probe for providing a second electrical signal as a function of rate of change of the probe signal. Differential amplifiers received the first and second signals, and provide a third signal as a function of a difference therebetween. An apparatus output signal is provided when such difference exceeds a preselected threshold.

Abstract: A method and apparatus for determining the condition of a fluid used in a process, such as a lubricating oil used in an internal combustion engine. A sample of the fluid is heated to an elevated temperature, a measurement is taken of an electrical characteristic of the fluid at that first temperature, the fluid is heated still further, and the aforesaid electrical characteristic is measured again. The two measured values of the electrical characteristic are used to calculate a quality parameter which, when compared with quality parameter values corresponding to fluid samples of varying condition, gives an estimate of the relative condition of the fluid sample under test. The test procedure also includes a measurement of the opacity of the fluid sample to visible light, with this measurement being used in conjunction with the calculated quality parameter to more accurately determine the relative condition of the fluid under test.

Abstract: A method for metering a reagent into a flowing medium includes adjusting a quantity of a reagent to be metered per unit of time into a flowing medium as a function of a thickness of a reaction zone in a catalytically active material. An apparatus for metering a reagent into a flowing medium includes a control unit, a device associated with the control unit for detecting a thickness of a reaction zone, and a metering device associated with the control unit for introducing a reagent into a flowing medium upstream of a catalytic converter as seen in flow direction of the medium. The control unit adjusts a quantity of the reagent to be metered into the flowing medium per unit of time by the metering device, as a function of a thickness of the reaction zone.

Abstract: The presence of air bubbles entrained in a liquid flowing through a tube is detected flowing the liquid through a conduit which comprises a conductivity cell with a continuous path configuration. An electrical current is induced in the liquid in the conductivity cell. The electrical current in the liquid in the conductivity cell is sensed and interpreted, a decrease in the electrical current being indicative of the presence of an air bubble in the liquid. The conductivity cell comprises an upstream connection, a downstream connection, and two branches connecting the upstream connection to the downstream connection with a continuous path configuration from the upstream connection to the downstream connection through one of the two branches and returning to the upstream connection through the other one of the two branches.

Abstract: An apparatus for conducting electrochemiluminescence test measurements consisting of a fluid container having a fluid flow path, a first counter electrode positioned within the fluid container directly secured to a transparent mounting block and having an electrode surface exposed to fluids within the fluid flow path, a working electrode with an electrode surface being displaced from the electrode surface of the first counter electrode laterally with respect to the flow direction of fluid within the fluid flow path.

Abstract: An automatic self-calibration system for digital teraohmmeter wherein a built-in standard resistor is provided. The system is able to calibrate the values of the key components by taking the standard resistor as reference. The calibration procedure of the invention is controlled by a computer and executed automatically. The system is used to measure high-resistance standards up to 10.sup.15 .OMEGA. where the standard uncertainty does not exceed 100 ppm after a traceable calibration.

Abstract: A method and device is disclosed for determining the distribution of charge and size in a colloidal system. The arrangement disclosed is adapted to measure these characteristics in an inhomogeneous colloid. A colloid is subjected to a steady or slowly varying force which moves the particles at a rate that depends on their radius or charge and thereby sets up spatial inhomogeneities in the suspension, and to either a unsteady mechanical force or an unsteady electrical force, and the resulting electrical or acoustic effects sensed. Monitoring these characteristics over time and subsequent calculation allows the determination of charge and size distribution, for each species present.

Abstract: An electric resistance measuring device situated in fluids, comprising; a housing having a bore therethrough, the bore having a seat; a movable door means situated in the bore, engagable with the seat; whereby, fluid movement disengages the door from the seat, changing the electrical resistance between the seat and the door. Such a device can detect leaks which increase the electrical resistance between the seat and the door. A panel provides selector means which can be set at different modes, each mode providing a different period of time in which fluid can be used continuously without interruption. If fluid movement exists after such period, a cut off valve will shut off the fluid. Such a device can be installed in line with fire sprinklers, such that the device will detect a fire and will send a signal to a central station.

Abstract: An integrated device test system (10, 40) having AC and DC measurement modes of operation comprises a drive circuit (11, 41), a programmable measurement unit (12) and a switch (18). The drive circuit (11, 41) may be a current mode drive circuit (11) or a voltage mode drive circuit (41). The drive circuit (11, 41) is coupled to the programmable measurement unit (12) and a device under test (64). In a DC mode of operation, the switch (18) is configured to couple a sense terminal (39) with one end of an isolation resistor (66). A second end of the isolation resistor (66) is connected to a pin (63) of the device under test (64). In an AC mode of operation, the switch (18) is configured to couple the sense terminal (39) with the drive circuit (11, 41) and the force terminal (35) of the programmable measurement unit (12).

Abstract: A monitor current to a squib as an air bag actuating element conducts in one and the opposite directions alternately. Each produced voltage value is differentially amplified with a positive reference voltage and a difference between the amplified voltages are calculated. Thus, an offset voltage of an operational amplifier used for the differential amplification is cancelled, and the difference between the two detected voltages becomes a voltage value which will be produced by a monitor current twice as large in current level. Thus, the squib is diagnosed accurately.

Abstract: A method of determining cell membrane strength is disclosed, using focused light of selected frequency and energy density. The method is also useful in diagnosing the presence of certain diseases in cells, by comparing the membrane strength of cells exposed to cell-characteristic altering drugs to the membrane strength of a control group of cells.

Abstract: A capacitive bend sensor includes a first element having a comb-patterned portion of conducting material, and a second element having a comb-patterned portion of conducting material. A dielectric material is disposed between the comb-patterned portion of the first element and the comb-patterned portion of the second element. The first element is bonded to the second element such that the comb-patterned portion of the first element slides relative to the comb-patterned portion of the second element when the first and second elements are bent. Bend angle is measured according to the alignment of the comb-patterned portion of the first element and the comb-patterned portion of the second element. The sensor may be coupled to a human finger to measure bend angle of the finger, or may be coupled to a joint of a human body to measure bend angle of the joint.

Abstract: A standard resistor having a known resistance value is connected to one transistor in a drive IC. The drive IC has a plurality of transistors each controlling on/off switching of a heating element. The saturation voltage of each transistor is generally the same. One of a plurality of transistors is turned on, and a discharge time required for a capacitor to discharge via a standard resistor or via each heating element and lower its voltage to a predetermined voltage is measured. The resistance value of each heating element is determined from a ratio of a discharge time via each heating element to a discharge time via the standard resistor and the resistance value of the standard resistor. A difference between the standard resistance value and a resistance value of each heating element generates a bias heat energy error during bias heating and an image heat energy error during image heating.

Abstract: Triboelectricity, that is the electrostatic charging of materials by rubbing them against one another, is used to identify particular plastics materials which produce a characteristic charge polarity when rubbed against another known material. An apparatus (24) for carrying out this identification mounts different reference materials (30, 32, 34) so that they can be rubbed against the material (44) to be identified to create electrostatic charges which are then processed by a logic circuit to identify the nature of the sample.

Abstract: An apparatus for determining the characteristics of a particular ionization chamber by measuring the capacitance of the chamber and using that capacitance to identify the particular type of chamber being used to measure the ionizing radiation.

Abstract: A circuit layout for measuring ion concentrations in solutions using ion-sitive field effect transistors is provided. The circuit layout makes it possible to represent the threshold voltage difference of two ISFETs directly and independently of technological tolerances, operationally caused parameter fluctuations, and ambient influences. The circuit layout includes two measuring or test amplifiers, with in each case two differently or identically sensitive ISFETs and two identical FETs. The ISFETs and FETs are connected in such a manner that at the output of the first measuring amplifier occurs the difference of the mean value of the two ISFET threshold voltages and the FET threshold voltage and at the output of the second measuring amplifier occurs the difference of the two ISFET threshold voltages. The output of the first amplifier is connected to the common reference electrode of the four ISFETs.

Abstract: The invention provides a compact device and simple method for circulating fluid over the surface of a membrane. The device comprises a housing that in combination with the surface of the membrane defines an enclosed volume through which the fluid is circulated. Some embodiments will include a membrane holding layer, a fluid dispersing layer, or both. The membrane holding layer has an opening through it to expose a predetermined surface area of the membrane to the fluid. The dispersing layer has a set of openings, typically slits, through the dispersing layer to disperse fluid over the surface of the membrane. Some embodiments may include electrodes for sensing or applying electrical potential to the membrane. A particularly preferred embodiment comprises a double sided device including a first housing, dispersing layer and membrane holding layer on one side of a membrane and a second housing dispersing layer and membrane holding layer on the other side of the membrane.

Abstract: In a process and a circuit arrangement for measuring the resistance of a resistance sensor, for instance a wetness sensor, via a rate of change of the charge of a capacitor, a measurement cycle consisting in each case of a charging of a capacitor, a discharging of the capacitor over the resistance sensor, and thereupon a measurement of the charge remaining in the capacitor, the direction of the discharge current through the resistor changes from measurement cycle to measurement cycle.

Abstract: Fluid transmission pipelines and similar structures which are cathodically protected from electrolytic corrosion and are disposed in urban areas under pavements and other structures which prevent access to the soil for verifying pipe-to-soil potentials are subjected to pipe-to-soil potential measurements using a reference electrode disposed in a container which has a permeable bottom and which is capable of saturating a pavement layer with a brine electrolyte to provide electrical conductivity between the reference electrode and the soil. Validation of electrical conductivity is made by a second reference electrode of a dissimilar metal which is also disposed in a container having a permeable bottom and an electrolyte which permeates the pavement layer and establishes electrical conductivity between the soil and the second reference electrode. Potential measurements between the first and second electrodes validate ion transport between the soil and the first reference electrode.

Abstract: A method for detecting extent of cross-linking of a high impedance polymer material during a pre-cure stage, the method comprising the steps of:a) applying a test signal through a sensor to the polymer material in the pre-cure stage to determine a level of impedance and corresponding sample voltage representative of a degree of cross-linking within the material;b) applying the same test signal through the sensor to a reference material having a fixed resistance to determine a reference voltage;c) determining a voltage difference between the test signal applied to the polymer at pre-cure stage and the test signal applied to the reference material as the reference voltage;d) correlating the voltage difference as a relative indicator of the extent of cross-linking which has occurred within the polymer material, based on comparison of magnitude of the voltage difference with respect to a comparable potential range of impedance for the polymer material from its lower impedance stage at minimal cross-linking to its

Abstract: A metal particle detecting sensor (10), having a simple structure, can perform in-line analysis for metal particles in fluid and also can precisely estimate or detect the number of metal particles for each particle size. Metal films (1) and insulating films (2) are alternately laminated one upon another, and every other metal film (1) in the laminate is connected in parallel with one another to one of two lead wires (3a, 3b) so as to form comb electrodes in the laminate of the sensor, and one end face of the laminate is immersed in a fluid (4) containing metal particles so as to detect the metal particles.

Abstract: A method for determining the degree of deterioration of oils or fats for deep-frying or frying foods is disclosed. The specific ohmic resistance of the oils or fats is measured and the extent of the fall of this resistance with increasing deep-frying time or frying time is used as a correlation for the degree of deterioration of the oils or fats.

Abstract: A metal-insulator-semiconductor diode sensor having a Pt/Ir alloy and/or a Pt/Sn alloy electrode is sensitive to and can detect ethylene. An array of metal-insulator-semiconductor diode sensors having varying sensitivity responses can indicate a fault in an electrical transformer by the detection of at least one of the key fault gases CO, H.sub.2, C.sub.2 H.sub.2 and C.sub.2 H.sub.4.

Abstract: The invention provides a compact device of simple construction for holding a membrane in contact with a pair of fluids, one on each side of the membrane. According to the invention, the membrane holder comprises a base and an upper cap, with the membrane held between them. Fluids may be circulated over the surfaces of the membrane. Electrode ports are provided through which electrodes may be placed in proximity to the membrane for measuring or applying electrical potential across the membrane. The membrane holder comprises a base, which includes a lower plate and a center plate secured thereto, and an upper cap, which screws into the base by means of a threaded connection between them. The upper cap may be sealed to provide an enclosed volume for holding one of the fluids or the upper cap may be open to provide an open reservoir for holding the fluid. One or more membrane holders according to the invention may be placed in and held by a specially constructed heater stand.

Abstract: A chip detector is an open circuit device that attract metal chips circulating throughout a piece of equipment such as a transmission. If a chip closes the circuit in the chip detector, then it is subjected to a first pulse of energy in an attempt to burn or displace it from the chip detector contacts. The energy content of the first pulse is selected to burn fuzz, which represents chips of an acceptable size. If the chip remains in the chip detector, then it is subjected to one or more additional pulses each having a greater energy content than the first pulse. The number of pulses and their energy contents are recorded to determine the size of the chips captured by the chip detector and to provide a history of the equipment being monitored. If the chip in the chip detector exceeds a predetermined threshold, then an indication is given on a user interface.

Abstract: A method for detecting extent of cross-linking of a high impedance material during a shelf life, slow state transition or during use, the method including: applying a test signal through a sensor to the material and through a reference material; determining a voltage difference between the test signal applied to the material and the reference material as the reference voltage; and correlating the voltage difference as a relative indicator of the extent of chemical change which has occurred within the material. Also disclosed is a device for implementing the subject method.

Abstract: An inactive state termination tester for determining the number of terminators connected to a bus when the bus is inactive. The termination tester monitors the bus for determining when it is inactive. During the periods of bus inactivity, the termination tester senses the bus to determine the number of terminators connected to the bus. The termination tester then displays how many terminators were detected and/or generates a signal to either enable or disable, respectively, a controllable bus terminator depending on if there are not enough or too many terminators determined to be connected to the bus. Furthermore, the termination tester maintains the controllable bus terminator in the proper enable or disabled mode whenever bus activity resumes.

Abstract: A system for lapping a magnetoresistive (MR) sensor on a slider to a proper height is disclosed. The system comprises simultaneously lapping the MR lap monitor and the MR sensor positioned on the slider until a resistance of a variable resistor located within the MR lap monitor is approximately equal to a resistance of a target resistor located within the MR lap monitor. During the lapping process, a reference resistor located within the lap monitor is compared to both the variable and target resistors to prevent a lapping failure. In one preferred embodiment, the reference, target, and variable resistors are formed from a ferromagnetic metal alloy. The MR lap monitor and the MR sensor are lapped until a height of the ferromagnetic metal alloy forming the variable resistor is approximately equal to a height of the ferromagnetic metal alloy forming the target resistor.

Abstract: A sensor determines a course of concentration of an adsorbent substance, such as ammonia NH.sub.3, diffusing out of a flow medium through a surface of a sensor material into the sensor material, as a function of a distance from the surface. Individual pairs of contacts are connected to supply leads and are disposed in the sensor material and optionally on the surface of the sensor material, for determining electrical conductivity of the sensor material between the contacts of the individual pairs of contacts.

Abstract: An apparatus for conducting measurements of electrochemiluminescence including a movable sample container support in the form of a carousel having a plurality of spaced apart support positions, an electrochemiluminescence testing device, a motor system to move the sample container support in a predetermined sequence, a sample transfer device to transfer sample from containers in the support positions to the testing device, and a detection system to detect the presence of a sample container and to produce an actuation signal based on the detected presence of the sample container.

Abstract: An oil deterioration sensor includes a housing, a substrate with a first capacitive plate mounted within the housing, a second capacitive plate mounted to the housing close to the first capacitive plate, and a total reference capacitor which includes an external fixed reference capacitor. The second capacitive plate is mounted to the housing such that oil freely circulates within a gap between the first and second capacitive plates thereby defining an oil deterioration sensor capacitor. The respective capacitances of the oil deterioration capacitor and the total reference capacitor provide an engine oil deterioration indication for the oil within the gap. The first capacitive plate is divided into a major sensing area, and a minor sensing area covering a relatively small portion of the total area of the first capacitive plate. The major sensing area and the second capacitive plate form the oil deterioration sensor capacitor.

Abstract: A circuit for determining the operability an airbag squib resistor. The circuit includes a current source, the squib resistor to be measured, a first resistor whose resistance is equal to the minimum acceptable resistance of the squib resistor, a second resistor whose resistance is equal to the maximum acceptable resistance of the squib resistor, a voltage-to-current converter, a capacitor, a comparator, and a microprocessor with a counter. A first switch connects the squib resistor and first and second resistors in series. A second switch couples the inputs of the voltage-to-current converter individually across the squib resistor and first and second resistors. As the second switch is coupled to the squib resistor, the first resistor or second resistor, a third switch is opened to initiate charging of the capacitor which is coupled to the output of the voltage-to-current converter. A time measurement is made of the time required for the capacitor to charge to a predetermined threshold voltage.