Abstract: The invention relates to a sensor for the measurement of gas concentrations in a gas mixture, comprising a ceramic sensor tube that is closed at one end, arranged in a casing, and exhibits an outer surface which consists at least partially of a solid electrolyte material, and with at least one sensor contact and at least one heating contact with an active heating surface arranged along its exterior. To provide a gas sensor with a short response time that continues to operate precisely and with long-term stability in hot exhaust gases, sensor contacts are screen-printed onto the sensor tube, where at least the active heating surface is arranged in rotational symmetry around the perimeter of the sensor tube and where the heating contact is arranged on an electrically insulating layer applied to the solid electrolyte material in such a way that it does not cover the sensor contact, of which there is at least one.

Abstract: The control arrangement comprises an oxygen linear test sensor located along the exhaust duct of an internal combustion engine, the sensor having a chamber able to receive part of the exhaust gas and two electrolytic cells of which one is electrically piloted; the arrangement having a retro-operation test circuit able to adjust the current piloted to the cell to give rise to an oxygen ions draining mechanism from and/or towards the chamber which induces the stoichiometric condition within the chamber itself, and an outlet circuit able to convert the piloted current into a first signal representative of nature of the mixture fed to the engine; the arrangement being provided with a memory circuit which memorises the value of a compensation resistance of the eventual spreads of the piloted current of a correcting circuit receiving the stored value of the compensation resistance and able to ensure a correction for the first signal to recover the spreads of piloted current to the cell; the correcting circuit provi

Abstract: Apparatus for detecting the NOx concentration includes a first measurement chamber 20 communicating with the gas under measurement via a diffusion rate defining layer 4d and a second measurement chamber 26 communicating with the first measurement chamber 20 via diffusion limiting layers 6d, 22d. A first pump current IP1 is controlled so that an output of a Vs cell 6 will be equal to the reference voltage VCO for controlling the oxygen concentration in the first measurement chamber 20 to a pre-set low value. A constant voltage is applied across the second pump cell 8 for decomposing the NOx component in the second measurement chamber 26 for pumping out oxygen for detecting the NOx concentration from a second pump current IP2. The sensor temperature is detected from the internal resistance of the Vs cell for controlling the current supplied to the heaters 12, 14. If the temperature of the gas under measurement is changed rapidly, the sensor temperature is changed.

Abstract: Using a sole Nox sensor Nox concentration and oxygen concentration are measured accurately. A measurement device for measuring NOx concentration and oxygen concentration comprises an NOx sensor 2 having a first measurement chamber 20 communicating via a diffusion rate regulating layer 4d with the gas under measurement and a second measurement chamber 26 communicating with the first measurement chamber 20 via diffusion rate regulating layers 6d, 22d. A first pump cell 4 and an oxygen concentration measurement Vs cell 6 are formed on the first measurement chamber 20, while a second pump cell 8 is formed on the second measurement chamber 26. Inside of the first measurement chamber 20 is controlled to a constant low oxygen concentration by controlling the first pump current IP1 so that output of Vs cell 6 will equal a reference voltage VC0. By applying a constant voltage across the second pump cell 8 NOx in the second measurement chamber 26 is decomposed to pump out oxygen.

Abstract: The accuracy and temperature-independence of ion-selective electrode meters having a logarithm resistance temperature correction incorporated therein is enhanced by using a microprocessor controlled and measured circuit with switched reference and switched capacitor filter, and by adding a linear membrane resistance term to the algorithm to improve accuracy across a wide temperature range.

Abstract: The present invention provides an apparatus for measuring the concentration of a constituent to be detected in exhaust gas, which apparatus is capable of detecting with a high accuracy the concentration of the constituent to be detected in exhaust gas even though oxygen concentration in the exhaust gas varies. In an exhaust gas sensor 1 for use in the measuring apparatus, exhaust gas is introduced into spaces 15, 16 on both sides of an oxygen concentration cell element 4, and the oxidation catalyst activities of first to third electrodes 11 to 13 are adjusted so that there occurs a difference between the space 15 and the space 16 in consumption of the constituent to be detected, which consumption is caused by the oxidation of the constituent. Thus a concentration cell electromotive force is generated in the oxygen concentration cell element 4, and an oxygen pump element 3 pumps oxygen into or out of the space 15 so that the electromotive force is held at an target value EC not more than 10 mV.

Abstract: A constant current Iconst is applied to an electromotive force cell which is interposed between a gap (measurement chamber) of a fixed atmosphere and an oxygen reference chamber of a constant oxygen content, for measurement of a resistance value of the electromotive force cell, whereby the resistance value can be measured accurately irrespective of an oxygen content in an atmosphere to be measured by an oxygen sensor element or cell unit. The resistance value of the electromotive force cell is measured at a predetermined timing T2 after application of a current is started, so that a measure resistance value is free of a variation of a resistance value due to deterioration of porous electrodes of an electromotive force cell, such a variation being included in the measured resistance value in case the measurement is done by using an AC current, and therefore accurate measurement can be attained.

Abstract: A detecting unit of an oxygen sensor as an A/F sensor has a solid electrolyte layer and a diffusion resistance layer and generates a current value according to the concentration of oxygen in an exhaust gas by applying a voltage across electrodes on an exhaust gas side and an atmosphere side of the solid electrolyte layer. An oxygen supply/exhaust unit has a solid electrolyte layer and a pair of electrodes formed on both faces of the solid electrolyte layer, and supplies oxygen near to the electrode on the atmosphere side of the detecting unit or exhausts oxygen near the electrode. A control unit controls, in response to a limit current value detected by a current detection unit, the amount of supply or exhaust of oxygen of the oxygen supply/exhaust unit on the basis of the detected current value.

Abstract: Corrosion of a metal member under heat transfer condition is monitored by using a test coupon made of the same material as that of the metal member. The test coupon may have a welded portion and a crevice. One substantial surface of the test coupon is heated by a sheet shaped heating element, and at least one portion of the other surface of the test coupon is contacted with the corrosive fluid. After detecting a status of corrosion of the test coupon, the corrosion of the metal member is monitored based on the results of the detection. In case a counter electrode or reference electrode is used, the electrode is immersed in the corrosive fluid, and electrical signals between the test coupon and the electrode are measured. Then, the corrosion of the metal member is monitored.

Abstract: A gas sensor comprises a main pumping cell for pumping-processing oxygen contained in a first chamber, a feedback control system for comparing a partial pressure of oxygen in the first chamber with a first reference value to control the main pumping cell so that the partial pressure of oxygen has a predetermined value at which NO is not decomposable, an auxiliary pumping cell for pumping-processing oxygen in the second chamber, and a measuring pumping cell for pumping-processing oxygen produced by decomposition of NOx.

Abstract: An oxygen sensor 3 having a heater 2 capable of providing an improved temperature increasing characteristic, while maintaining an increased amount of introduced air and a high production efficiency. The sensor 3 includes a sensor element 1 having an air chamber 100 in which a heater 2 is arranged. The heater 2 has a rectangular cross sectional shape. In order to produce the heater 2, onto a green ceramic sheet, a heater of a predetermined pattern including a plurality of heater sections is printed. Then, to the printed sheet, different ceramic green sheets are applied so as to obtain a laminated body. The laminated body is subjected to a cutting so as to produce an intermediate body in which a heater section is included. The intermediate body is subjected to a firing to obtain a completed heater.

Abstract: The present invention is directed to an electrochemical gas sensor network. The network includes a gas sensor for receiving a gas and for generating a target gas concentration signal. The gas sensor has an output terminal for providing an output signal that is a product of the target gas concentration signal and a first transfer function. The network also includes a compensation circuit having an input terminal connected to the output terminal of the gas sensor. The compensation circuit also has an output terminal which provides an output signal that is a product of the output signal from the gas sensor and a second transfer function. The second transfer function is approximately an inverse of the first transfer function. The present invention also contemplates a method of compensating for the attenuation of a high frequency component of an output signal of a gas sensor.

Abstract: A solid electrolyte gas analyzer includes an analyzer circuit housed in an electronics housing and a probe housing for immersion in the gas of interest. The electronics housing mounts directly to the probe housing, preferably through a standoff. The analyzer circuit is powered by an AC line input and includes a switching power supply to convert the AC line input to DC power useable by the analyzer circuit. The analyzer circuit also includes a heater circuit controlling a heater in the probe housing. The power supply and the heater circuit automatically adjust to different AC line input voltage levels. The switching power supply efficiently supplies DC power to other portions of the analyzer circuit with little heat generation.

Abstract: A calorimetric hydrocarbon gas sensor (10) includes an electrochemical oxygen pump (18), a sensing element (12), and a multi-layered substrate (26) separating the sensing element (12) from the electrochemical oxygen pump (18). The multi-layered substrate (26) includes a plurality of overlying insulating layers, in which at least one intermediate layer (60) supports a first primary heater (58), and in which another intermediate layer (52) supports a temperature compensation heaters (50a, 50b). The primary heater (58) functions to maintain the calorimetric hydrocarbon gas sensor (10) at a constant, elevated temperature, while the active compensation heater (50a) functions to maintain substantially equal temperatures as determined by the thermometers (46a, 46b) located on an intermediate layer (48) overlying the compensation heaters (50a, 50b).

Abstract: Disclosed is a gas sensor comprising a main pumping cell including a solid electrolyte layer contacting with an external space, and an inner pumping electrode and an outer pumping electrode formed on inner and outer surfaces of the solid electrolyte layer, for pumping-processing oxygen contained in a measurement gas introduced from the external space on the basis of a control voltage applied between the electrodes; a feedback control system for adjusting the control voltage to give a predetermined level of a voltage between the inner pumping electrode and a reference electrode disposed at a reference gas-introducing space; and a heater for heating at least the main pumping cell to a predetermined temperature; wherein the outer pumping electrode is connected to a negative side lead wire of the heater.

Abstract: An apparatus for measuring ion concentration of a solution includes an ion sensitive field effect transistor (ISFET), a reference device, an ISFET control circuit, a memory, a measurement circuit and a diagnostic circuit. The ISFET has a drain, a source, an ion sensitive gate region and a plurality of device characteristics. The reference device is separated from the gate region by a sample solution. The ISFET control circuit is coupled to the ISFET and operates the ISFET at a drain-source voltage V.sub.DS and at n successive drain currents I.sub.Di and corresponding gate-source voltages V.sub.GSi, wherein i is an integer from 1 to n and n is an integer greater than 1. The memory stores the plurality of device characteristics and the n successive drain currents I.sub.Di and gate-source voltages V.sub.GSi. The measurement circuit measures ion concentration of the solution as a function of at least one of the n successive drain currents I.sub.Di and gate-source voltages V.sub.

Abstract: An oxygen sensor based on a metal-air cell, typically a commercially available zinc-air battery of the type used in hearing aids. The cell, which admits oxygen to generate electric current at its cathode is disposed in a mechanical housing which restricts the flow of oxygen to the cell, and is connected to an electrical circuit which provides a variable resistance load, the load increasing as current flow through the circuit decreases, to prevent hydrogen evolution at the cathode. Current flow through the cell is measured, and is proportional to oxygen concentration.

Abstract: A field effect transistor (10) for chemical sensing by measuring a change in a surface potential of a gate electrode (48) due to exposure to a fluid has a semiconductor substrate (12) with a trench (18,20). The trench has a first sidewall (30) and a second sidewall (32) disposed opposite the first sidewall to provide a fluid gap (50) for the fluid to be sensed. The gate electrode is disposed overlying the first sidewall of the trench, and a source region (54) and a drain region (56) are disposed in the second sidewall of the trench. A channel region (52) is disposed between the source and drain regions, and the gate electrode is disposed opposite the first channel region across the fluid gap. A heater (26) for regulating the temperature of the gate electrode is disposed in the first sidewall of the trench.

Abstract: A shaft-like heating member is inserted into and fixed to an oxygen sensing element of a hollowed shaft-like member, together with of a terminal member. A heating portion is located at a portion of the heating member closer to the extreme end thereof. The surface of the heating portion is resiliently pressed on the element inner wall in a side-abutting fashion. In this case, a guide mainly gives rise to the elastic force. With such a side-abutting structure, heat generated in the heating portion is directly transferred to the oxygen sensing element, and heats it. Heat radiated from a portion in the vicinity of its contact position additively heats the oxygen sensing element. Temperature of the oxygen sensor quickly reaches an activation temperature.

Abstract: An electrochemical gas sensor having a temperature sensitive element such as a thermistor arranged within the gas sensor in a temperature insulative fashion for preventing any variations in the temperature of the applied gases to be sensed to be immediately conveyed to the temperature sensitive element thereby providing accurate temperature compensation signals to be combined with the generated sensor electrical output signals. The temperature sensitive element or thermistor is mounted in a heat sink to the expansion membrane of the gas sensor to be responsive only to changes in the temperature variations imparted by the sensor electrolyte and not by the variations in the temperature of the gas sensor body and associated elements thereby providing correct temperature compensation signals without error producing time delays.

Abstract: An insulation layer system, in particular for gas sensors, is proposed, having at least one electrically conductive solid-electrolyte layer (10), an electrically conductive layer (20) and at least one electrically insulating layer (13) between the solid-electrolyte layer (10) and the electrically conductive layer (20). The material of the insulating layer (13) contains, prior to sintering, pentavalent metal oxides of niobium or tantalum as an additive, it being possible for the additive to diffuse into the adjoining solid-electrolyte layer (10) during sintering.

Abstract: According to the present invention, an oxygen concentration sensor for detecting an oxygen concentration includes a sensor element having an atmospheric chamber therein, a heater inserted in the atmospheric chamber, and a holder for holding the heater in the atmospheric chamber. The holder includes a cylindrical portion for covering an outer periphery of the heater, and a plurality of cantilever elastic pieces provided at a lower portion of the cylindrical portion. The elastic pieces includes a heater supporting portion elastically contacting with the periphery of the heater and a fixing portion elastically contacting with an inner surface of the sensor element. In this way, it is possible to assemble a heater into a sensor element easily without causing damage to the heater.

Abstract: An on-line method for the continuous generation of alkali metal salts includes continuously reacting a source of acidity, a liquid having a low pH value, with a source of alkalinity, a liquid having a high pH value, while continuously monitoring an electrical parameter of the resultant in salt which is indicative of its pH value. The monitored value is used to adjust the relative flow rates of the input liquids so as to dynamically maintain the pH value of the resultant salt within a predetermined range. In an apparatus, the input liquids can be continuously supplied to a reacting element and the conductance of the resultant salt monitored for purposes of providing feedback control signals to adjust one or more flow rates.

Abstract: A system for measuring the content of foreign substances in a gas stream, for example oil in a stream of compressed air. The system includes at least one probe for collecting a given amount of gas. In the probe there is at least one sensor over which the sampled gas is passed. For optimum evaluation and for signaling certain states of operation, the sensor includes a temperature sensor for determining the temperature of the gas sample flowing past it, and a detector whose electrical resistivity or conductivity depends on the nature and density of the foreign substances in the gas. The output signal of the detector corresponds to the concentration of foreign substance in the gas stream, and is processed in an electronic evaluation unit.

Abstract: An oxygen sensor according to the present invention has battery element and a pump element in each of which porous electrodes are disposed on both faces of a solid electrolyte substrate. A minute current is supplied to the battery element after the start of energizing a heater and the activation of the sensor elements are judged on the basis of an interelectrode voltage generated at this energizing. A heater voltage is set to be 12V at the start of energizing. When the time period necessary for the interelectrode voltage to reach a predetermined voltage is short, the applied voltage is lowered to 11V. As a result, the time period necessary for judging the sensor elements to be activated can be made substantially constant irrespective of variations in sensor characteristics. After the activation judgment, the variation of the temperature of the sensor element is monitored on the basis of the interelectrode voltage.

Abstract: A selective gas sensor (10) for detecting a particular compound, or group of compounds, such as non-methane hydrocarbons, within a high temperature gas stream (12) includes an oxygen generation system (14) positioned over an oxygen diffusion region (15). The oxygen generation system (14) and the oxygen diffusion region (15) provide oxygen through a medial temperature control zone (20) to a sensing element (16). The temperature and flux of hydrocarbon components within the high temperature gas stream (12) are regulated by components within the high temperature control zone (20) and by an external temperature control zone (22) in thermal contact with the sensing element (16).

Abstract: A method and apparatus for rapidly measuring chemical properties of a solution using a plurality of devices having relatively long thermal time constants selectively coupled to a control means. Current I.sub.d flows through only one device at a time. A timing logic control circuit controls the timing of the drain switch and, if present, the reference switch. The output of the multiplexing circuit is sampled a precise amount of time after each device begins conducting current. The temperature at the sample time is a constant. The characteristics of the solution in which the device is immersed is the only variable in the operation of the device (i.e., I.sub.d, and V.sub.ds are held constant). By sampling the output a predetermined amount of time after the device has been turned on, the temperature rise is controlled.

Abstract: A method and apparatus are disclosed for measuring atmospheric pressure in conjunction with an air-fuel ratio sensor of the type comprising a concentration cell with atmospheric air and exhaust electrodes on opposite sides of a solid-state electrolyte having oxygen ion conductivity. During an atmospheric pressure measuring cycle, oxygen ions are pumped from the atmospheric air electrode to the exhaust electrode, in a quantity which is either predetermined at a fixed value, or is sufficient to bring the cell to an equilibrium state. Atmospheric pressure is then calculated from measured emf of the cell, using an experimentally derived functional relationship. In a second embodiment, ions are pumped until a predetermined change of the concentration cell emf is achieved, and atmospheric pressure is determined based on the amount of time required to achieve such change. The atmospheric pressure measuring mode is operated on a time shared basis with the air-fuel ration detection mode.

Abstract: A device for temperature measurement at an oxygen probe, in particular a lambda probe, having a solid electrolyte arranged between two electrodes. At least one of the electrodes is provided with two spaced terminals for measuring an electrical resistance of the electrodes.

Abstract: An electrochemical gas sensor assembly comprises an electrochemical gas sensor for sensing a selected gas. A filter is provided through which gas to be sensed must pass before reaching the sensor, the filter being adapted to prevent at least one non-selected gas from reaching the sensor but permitting passage of the selected gas. A temperature control system controls the temperature of the filter.

Abstract: A method for correcting an output from an electrochemical cell sensor, having an output responsive to a concentration of sensed species in a stream, a pressure and a temperature in an interactive non-linear relationship, comprising the steps of providing a pressure sensor for producing an output responsive to a pressure in proximity to the electrochemical sensor; providing a temperature sensor for producing an output responsive to a temperature of said electrochemical sensor; and processing the outputs of the electrochemical sensor, pressure sensor and temperature sensor in a neural network having an output function which compensates said electrochemical sensor for changes in pressure and temperature to indicate a concentration of the sensed species.

Abstract: To shorten the time during which oxygen concentration cannot be detected, the temperature of an oxygen concentration sensor is detected by negatively biasing the sensor using a bias control circuit. A microcomputer estimates a saturated current thereof at one time before the current flowing through the sensor section ends rising based on a current detected by a current detecting circuit at that time. Further, the sensor is positively biased right after the elapse of a negative bias voltage application period by the bias control circuit. The microcomputer determines the air-fuel ratio based on the current flowing through the sensor at that time. The period in which the negative bias is applied is variably set appropriately by the microcomputer in response to changes of engine temperature and intake air amount. Furthermore, to activate the sensor quickly, the temperature of the sensor section is detected and a heater is controlled based thereon.

Abstract: The invention is based on a planar sensor element for determining the oxygen content of gas mixtures, particularly in internal combustion engines such as those found in automobiles. The sensor element comprises a measuring cell and an integrated heat conductor embedded in electric insulation all of which rest on a solid electrolyte substrate. At least one hollow chamber separates one or several parts of the insulation from the solid electrolyte substrate in order to effect an improved decoupling of the sensor's heat conductor from its measuring cell.

Abstract: A sensor arrangement for determining at least one of gas components and gas concentrations of gas mixtures including CO, NO.sub.x and HC in exhaust gases of internal combustion engines, includes a measuring element which has a sensitive region; and a pump cell that includes a solid electrolyte and inner and outer pump electrodes which are opposingly disposed at least on the solid electrolyte and which effect an oxygen transfer to the measuring element, wherein the pump cell and the measuring element are spatially separated from one another, are located in different temperature zones during operation of the sensor arrangement, and are connected to one another by a diffusion segment through which oxygen can diffuse from the pump cell to the measuring element.

Abstract: The invention relates to a measuring sensor having an internal pump oxygen reference atmosphere which, in turn, has a device for compensating pressure which is so dimensioned that, on the one hand, mechanical damage because of overpressure in the reference volume is reliably prevented and, on the other hand, external influences on the composition of the pumped measured gas atmosphere are substantially excluded. The device for compensating for pressure is so dimensioned according to the invention that the particle exchange between ambient air and gas to be measured is opposed by a resistance which is defined by the limit current principle.

Abstract: A control device and associated methodology select from at least two on-line sensors to assure an accurate and reliable feedback input to control the heat treating conditions within a furnace. The device and methodology also serve to provide an "alert" or "early warning" of gradual degradation of sensor performance, before ongoing heat treating operations are adversely affected.

Abstract: Device for prolonging the effective usage time (service life), arrangement and process for minimizing temperature effects in any ion-selective polymer membrane electrode measuring chain (ISPE measuring chain), wherein one solution or both solutions directly adjoining the polymer membrane (outer measuring solution and inner potential drain solution) are saturated or supersaturated with the compounds which normally tend to bleed out; and wherein the isotherm intersection of an ion-selective measuring chain with redox drain elements is optimally located in the middle of the measuring range such that this middle is located at ca. 0 mV.The device may be used for monitoring of groundwater with opposite changes in the concentrations of nitrate and ammonium, evaluated in a special device, with electronic data processing and intermediate data storage (in RAM pack) at the site of the measurement and data polling as needed to a central unit by telemetry.

Abstract: An electric conductivity-measuring cell comprises a pressure container serving also as an outer electrode and provided with an inlet port of a liquid to be measured and an outlet port and an inner electrode provided within said pressure container so as to simplify it in construction and improve a measurement in accuracy.

Abstract: A small oxygen electrode and a method of bonding a fluorine resin film are disclosed. This small oxygen electrode includes a flat electrode substrate having at least two electrodes (a working electrode and a counter electrode) formed thereon, and a container substrate having dents formed to confront the two electrodes and contain an electrolyte therein. The container substrate is bonded to the flat electrode substrate, so that the dent confronting the electrode constituting the working electrode has a through hole extending to the side opposite to the flat electrode substrate and a gas-permeable film is formed to cover the through hole. By using this dent structure, the preparation of an oxygen electrode can be conducted while maintaining a wafer form throughout the process, and formation of an electrode pattern can be facilitated.

Abstract: A detector for detecting a physical quantity as a quantity of electricity has a detection portion, a portion for stimulating the detection portion and a signal processing portion, wherein a calibration signal is supplied from the signal processing portion to the detection portion via the stimulating portion so as to measure a specific response of the detection portion, whereby self-calibration and correction of the characteristic of the detector are performed in accordance with an amount of a change in the response.

Abstract: An electrocatalytic device for sensing gases. The gas sensing device includes a substrate layer, a reference electrode disposed on the substrate layer comprised of a nonstoichiometric chemical compound enabling oxygen diffusion therethrough, a lower reference electrode coupled to the reference electrode, a solid electrolyte coupled to the lower reference electrode and an upper catalytically active electrode coupled to the solid electrolyte.

Abstract: The sensor (1) comprises a sensor body (3) thermostatable by means of a first thermostating system (14,15) and having an outer surface (3a,40a) for application to the human body (28) in heat conductive relationship therewith, said outer surface (3a,40a) forming the measuring surface of the sensor (1). The sensor (1) further comprises analyte sensing means (7,8) arranged in said sensor body (3) and being thermostated through said body (3) by means of the first thermostating system (14,15). The sensor (1) further comprises means (16,41) arranged in the sensor body (3) in heat insulated relationship therewith while in heat conductive relationship with a delimited surface part of the sensor measuring surface (3a,40a). The means (16,41) is thermostatable by means of a second thermostating system. The delimited surface part is located within the outer periphery of the sensor measuring surface (3a,40a).

Abstract: An apparatus for measuring the conductivity of an electrolyte comprises at least one conductivity cell, e.g., syringe-type conductivity cell and a constant temperature jacket. The syringe-type conductivity cell preferably employed in the apparatus comprises a generally longitudinal, cylindrical wall and two electrode rods which serve to define a volume for testing the conductivity of a sample in the volume. The constant temperature jacket comprises at least one longitudinal chamber for holding a conductivity cell, a temperature sensing device, and a fluid channel which is in fluid communication with a source of constant temperature fluid.

Abstract: An oxygen concentration measuring device capable of significantly shortening the period of time during which oxygen concentration cannot be measured. When measuring the temperature of a sensor main body, a microcomputer determines the temperature of the sensor main body by estimating a saturation current starting from a current detected by a current detecting circuit in a period of time before current flowing through the sensor main body finishes rising, after the sensor main body has been negatively biased by a bias control circuit. The sensor main body is positively biased by the bias control circuit directly after the period of time has lapsed. The microcomputer determines an air fuel ratio by using current in a period of time before current flowing through the sensor main body due to the positive bias finishes decreasing.

Abstract: A biosensing meter is provided that determines a value of an analyte in a biological sample. The meter employs an algorithm for determining the analyte value, which value is dependent upon ambient temperature about the biological sample when it is present in a reaction zone. The biosensing meter includes a processor and a temperature sensor. The temperature sensor is positioned within the meter's structure and thereby exhibits a delayed response to changes in the ambient temperature. The meter performs a temperature estimation method to overcome the delayed temperature response. The method commences by the meter repetitively and periodically acquiring temperature readings from the temperature sensor when the biosensing meter is both in an on state and in an off state. When the meter is in the on state, the algorithm estimates the ambient temperature by employing at least two most recent temperature readings and extrapolating therefrom to achieve an ambient temperature estimate.

Abstract: A solid-state oxygen microsensor which measures the potential difference (EMF) generated by two spaced apart electrodes deposited on a solid oxygen ion conducting electrolyte and located in a known and preferably constant temperature gradient in the same ambient atmosphere. Output voltage of the sensor is proportional to the temperature gradient established across the electrodes and the unknown oxygen partial pressure of the ambient atmosphere. The solid-state oxygen microsensor is useful for application to systems such as combustion systems to maintain and improve combustion efficiency levels and exhaust gas cleanliness.

Abstract: A solid-state oxygen microsensor measuring the potential difference (EMF) generated across two electrodes deposited on a solid oxygen ion conducting electrolyte and located in a constant temperature gradient in the same ambient atmosphere is provided. An output voltage of the sensor is proportional to the corresponding temperature gradient established across the electrodes and the oxygen partial pressure of the ambient atmosphere at such time. The solid-state oxygen microsensor is useful in the application of combustion systems, for example, to maintain and improve combustion efficiency levels and reduce undesirable emissions within the exhaust.

Abstract: Method and apparatus for electrochemical monitoring of oxidizing agents, such as nitrite, or reducing agents in a water system and for controlling concentration levels for protecting surfaces exposed to the water. The apparatus includes a probe for selective exposure to fresh water samples of the system. The probe is connected to an analyzer that operates the probe and measures agent concentration by a chronoamperometry technique. A controller selectively feeds an agent to the water system in accordance with a set point to maintain a desired concentration level.

Abstract: An improved electronic wiring board having a thermistor and at least one blood gas sensor supported, in close relation, one to the other, on one side of the board and a heater supported on the other side of the board to provide heat in response to temperature sensed by the thermistor, to at least the region where the thermistor and the blood gas sensor are positioned on the board to control the temperature of the region of the board within a narrow distribution of temperatures.

Abstract: A plastic covered nonconducting substrate with an electrical circuit means is secured to the extent to withstand the presence of liquids in contact with the substrate. The covered substrate can have the substrate with one or more fluid preconditionable electrical components, a housing secured to the substrate to maintain contact of the preconditioning fluid with the electrical component like a sensor, and moisture impervious seals to cover openings in the housing for the disposition of the preconditioning fluid in the housing for contact with the electrical component on the substrate. The housing can have one or more parts and have one or more channels for containing the preconditioning fluid.