Abstract: An apparatus for an integrated circuit comprising a thermal sensor (41-44), an A-D converter (58) coupled to the thermal sensor, wherein the thermal sensor provides an input to the A-D converter, and the A-D converter converts the input to a digital value representative of the thermal environment of the thermal sensor. The integrated circuit collects a data value at a location on an integrated circuit wherein the data value has a predetermined functional relationship to the temperature at the location. The integrated circuit converts the data value to a value representative of the thermal environment of the location on the integrated circuit.

Abstract: A circuit (1) for compensating for temperature with a sensor operating by the eddy current principle for measuring physical conditions of an object. The circuit includes an evaluation unit (3) for evaluating a measuring signal (100) of the sensor (2). The sensor (2) and the evaluation unit (3) are interconnected via a connection cable (4). For the purpose of minimizing or preventing to the greatest extent temperature caused interferences, an additional compensation line (5) is provided which compensates for the temperature of the connection cable (4). A corresponding method for compensating for temperature is described.

Abstract: A temperature controlled high voltage regulator for automatically adjusting the high voltage applied to a radiation detector is described. The regulator is a solid state device that is independent of the attached radiation detector, enabling the regulator to be used by various models of radiation detectors, such as gas flow proportional radiation detectors.

Abstract: First and second resistors (sensing elements) are connected in series between first and second potentials. The junction point voltage between the first and second resistor is supplied to an inverting input of a first operational amplifier. The non-inverting input is supplied with a reference voltage Vref generated by third and fourth resistors. A feedback resistor is connected between output and inverting input of the operational amplifier OP1. The difference between a temperature coefficient of resistance TCR of the sensing elements and a temperature coefficient of sensitivity TCS is equalized to a temperature coefficient of resistance of the feedback resistor. Further, the reference voltage is unchanged in accordance with the detected physical quantity or temperature variation.

Abstract: Methods for determining electrical and thermal properties of a heated pipeline are provided. During commissioning or at any time thereafter, a base curve of impedance versus temperature of the pipeline is determined, so that impedance measurements can thereafter be used to measure temperature of the pipeline. Continuous monitoring of impedance is provided to detect changes in conditions of the pipeline. Start-up procedures that decrease risk of damage to the annulus from arcing are disclosed.

Abstract: A power supply system for electrically heated pipelines is provided. A variable frequency drive supplies power to the pipeline from an external source of electrical power. An isolation transformer and a contactor or isolating switch may be used between the variable frequency drive and the pipeline. A controller may be used in the system to control special sequences of power level and other needs for heating a pipeline.

Abstract: An airfoil temperature control arrangement includes a resistive heater element. A plurality of detectors allow a controller to gather resistance information at various intervals along the resistive heater element. Determining the resistance of the corresponding portions of the heater element allows the controller to utilize a known relationship between resistance and temperature for the material selected to make the resistive heater element. In one example, a nickel alloy or other material having a high coefficient of resistance is chosen to provide the controller with the ability to determine a temperature for each portion of the heater element. The determined temperature information is used, for example, to monitor whether any portion of the heater element has become delaminated from the airfoil surface.

Abstract: A sensor mat configuration includes a sensor mat having row lines, column lines, and a plurality of force-dependent resistors connected between the row lines and the column lines to form a matrix having rows and columns. The sensor mat configuration includes a printed circuit board having a plurality of fixed resistors. The first terminal of each one of the plurality of the fixed resistors is connected to a respective one of the column lines, and the second terminal of each one of the plurality of the fixed resistors are connected together, thereby forming an additional row of the matrix. The resistances of the plurality of the fixed resistors are known within a narrow tolerance range, which enables these resistors to be used in measurements for accurately determining the resistances of the force-dependent resistors of the sensor mat.

Abstract: A temperature dependent sensitivity compensating circuit structure of a sensor is provided. The sensor includes a sensing element which has a TCS (Temperature Coefficient of Sensitivity). The circuit structure is designed to provide a temperature characteristic to current supplied to the sensing element, thereby compensating for a change in TCS of the sensing element.

Abstract: A temperature sensing apparatus comprises a temperature sensor, a current measuring device and temperature detection circuit. The temperature sensor contains a thermal resistor that is disposed near a motor and outputs voltages acting to the thermal resistor. The current measuring device measures quantity of current that is applied to the motor. The temperature detection circuit detects temperature of the motor according to the output voltages from the temperature sensor. And, the temperature detection circuit judges whether a predetermined quantity of current is applied to the motor during a predetermined time. When the predetermined quantity of current is applied to the motor during the predetermined time, the temperature detection circuit compares a temperature detected by the current measuring device with a predetermined temperature. When the detected temperature is lower than the predetermined temperature, the temperature detection circuit decides a wire of the thermal resistor breaks.

Abstract: A two-stage circuit configured to control the temperature of a device, having: a first stage connected to the device for controlling the temperature of the device; and a second stage having a temperature sensor and a heat source associated with the first stage for controlling the temperature of the first stage. An apparatus and method for controlling the temperature of an optical, electrical, or electronic device, or other analogous device provides a greater degree of control, i.e. control within a narrower band than is currently possible, by utilising a second stage of control associated with the first stage of control.

Abstract: Methods for determining electrical and thermal properties of a heated pipeline are provided. During commissioning or at any time thereafter, a base curve of impedance versus temperature of the pipeline is determined, so that impedance measurements can thereafter be used to measure temperature of the pipeline. Continuous monitoring of impedance is provided to detect changes in conditions of the pipeline. Start-up procedures that decrease risk of damage to the annulus from arcing are disclosed.

Abstract: A method of removing bias drift from the output signal of a sensor is provided. The method includes sensing a condition with a sensor and generating an output signal, differentiating the output signal, and comparing the differentiated output signal with a threshold change. The method also includes the steps of determining the presence of bias drift based on the comparison, generating a bias adjustment command signal based on the determined presence of bias drift, and adjusting the sensed signal generated by the sensor in accordance with the bias adjusted command signal so as to remove bias drift from the output signal.

Abstract: The present invention is a temperature sensor which is based on the actual temperature coefficients of a device in the circuit, rather than a predetermined threshold voltage that varies across different devices. This temperature sensor includes a circuit which determines the temperature of a device. More particularly, CMOS circuit is provided which uses a current source to generate charge and discharge voltages applied to a capacitor. These voltages are dependent on the temperature coefficient of a resistor in the current source. The charge and discharge times are then used to determine a frequency which is dependent on the temperature coefficient of the resistor. Thus, the temperature is sensed based on the output frequency of the circuit. Additionally, the present invention includes a mechanism which allows the temperature sensor to be activated or deactivated as needed.

Abstract: A bridge circuit serving as a detector of a physical variable such as pressure has four resistors forming a wheatstone bridge, one of the resistors changing resistance according to variations in the physical variable to be measured. Voltage difference between a mutually opposite pair of junctions of the four resistors is measured by one circuit and that between the other mutually opposite pair of junctions is measured by another circuit. The effect of temperature variation is calculated from these measured values to reduce the drift in the value of pressure calculated from the voltage imbalance of the wheatstone bridge.

Abstract: A sensing device includes a circuit that compensates for time and spatial changes in temperature. The circuit includes elements to correct for variation in permeability of a highly permeable core of a differential variable reluctance transducer as temperature changes. The circuit also provides correction for temperature gradients across coils of the transducer.

Abstract: A temperature compensated power detector generally comprises a detector circuit portion, which includes a detector diode, and a temperature compensation circuit portion, which includes a temperature compensation diode, that is operably connected to the detector circuit portion. The detector diode and the temperature compensation diode are connected in DC series with each other and develop substantially identical voltage drops. The detector circuit portion operates to detect a voltage from a power input. However, the detected voltage is subject to alteration due to temperature variations. The temperature compensation circuit portion develops a voltage that is also subject to alteration due to temperature variations. The temperature altered voltage of the temperature compensation circuit portion is used to cancel out the temperature altered voltage of the detector circuit portion allowing the power detector to produce a true voltage output.

Abstract: A two-stage circuit configured to control the temperature of a device, comprising: a first stage connected to the device for controlling the temperature of the device; and a second stage comprising a temperature sensor and a heat source associated with the first stage for controlling the temperature of the first stage. This invention provides an apparatus and method for controlling the temperature of an optical, electrical, or electronic device, or other analogous device. The invention provides a greater degree of control, i.e. control within a narrower band than is currently possible, by utilising a second stage of control associated with the first stage of control.

Abstract: A pressure detecting bridge circuit produces a sensor signal Sd. A temperature detecting bridge circuit produces a temperature signal St. A reference voltage generating circuit produces a reference signal Sa. An analog multiplexer processes these signals Sd, St and Sa in a time-divisional manner. A differential amplification circuit and an A/D conversion circuit are commonly used to obtain the digital data corresponding to the sensor signal Sd, the temperature signal St and the reference signal Sa. The temperature detecting bridge circuit includes reference resistance elements. By adjusting the design resistance values of the reference resistance elements, the variation width of the sensor signal Sd in a pressure measuring range of the pressure detecting bridge circuit is substantially equalized in advance with the variation width of the temperature signal St in a temperature measuring range of the temperature detecting bridge circuit.

Abstract: A bridge circuit serving as a detector of a physical variable such as pressure has four resistors forming a wheatstone bridge, one of the resistors changing resistance according to variations in the physical variable to be measured. Voltage difference between a mutually opposite pair of junctions of the four resistors is measured by one circuit and that between the other mutually opposite pair of junctions is measured by another circuit. The effect of temperature variation is calculated from these measured values to reduce the drift in the value of pressure calculated from the voltage imbalance of the wheatstone bridge.

Abstract: A sensor is provided with a conductive sensing element that has a composition adapted to provide a resistance large enough that predetermined magnitudes of voltage noise do not create a false indication of removal, e.g. by abrasion or corrosion. Also, the sensing element composition is adapted to provide a temperature coefficient of resistivity small enough that measurements are substantially independent of temperature. Resistance is preferably greater than 10 ohms and the absolute value of TCR is preferably less than 1000 parts per million per .degree. C. The conductive sensing element may be formed from several materials, including alloys of palladium or lead, particularly palladium-gold, lead-bismuth, or lead-palladium. A combination sensor is provided that includes an abrasion sensing element and a corrosion sensing element on the same substrate.

Abstract: A simplified method and apparatus for electronic pressure control with compensation for current operating temperature and pressures in which computer memory is employed for storing a plurality of firmware models which characterize the effects of temperature and pressure variations on (1) fluid flow through the flow restrictor, (2) the temperature sensor, and (3) the pressure sensor, so that control signals can be generated which compensate a plurality of thermally coupled sensors for changes in current operating temperatures and pressures.

Abstract: The present invention, generally speaking, provides for highly accurate correction of a sensor output using circuitry that is compact and inexpensive. In accordance with one embodiment of the invention, an output signal of a sensor having a sensitivity that varies as a function of temperature and that includes resistors connected to form a bridge is corrected by, first, modeling the sensitivity of the sensor using an expression that is the ratio of two polynomials; applying a voltage across the bridge; and controlling the applied voltage as a function of temperature substantially in accordance with the inverse expression.

Abstract: A portable grain moisture meter has a large 16 character digital display allowing an alphabetical list of grain selections to be selectably displayed in full text format and subsequently tested for moisture content with the test results also displayed on the same display. The meter also has provisions for calibrating the meter to a remotely located meter and has dual temperature transducers for achieving automatic grain temperature compensation by monitoring both the grain temperature along with the cell temperature.

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 device for adjusting sensor signals, and, in particular, signals supplied to a sensor for detecting an operating parameter of a motor vehicle having an internal combustion engine. The device has adjustment elements and a current divider, which includes at least one adjustable resistor and a second resistor, coupled in series with the sensor.

Abstract: A humidity detection circuit includes a bridge circuit containing temperature sensing elements. The bridge circuit is connected in series to a current limiting resistance, a current controlling element and a power supply. There is a set of resistances arranged in parallel with the current limiting resistor and the bridge circuit. A voltage comparing circuit is operatively connected to the bridge circuit the current limiting resistance and the set of resistances. A control section is provided to detect the potential of a junction between the bridge circuit and the current limiting resistance. Based upon the detector potential, the humidity detection circuit changes resistance value of a resistor in the set to an optimal level so that temperature drift does not occur.

Abstract: An apparatus for monitoring current through a lamp circuit that uses a series resistance shunt in the circuit with one end connected to a current source and the second end connected to the lamp. The apparatus includes a comparator that is connected across the shunt and has a threshold switching voltage wherein a voltage across the shunt that is larger than the threshold switching voltage will switch the comparator on and a voltage across the shunt that is smaller than the threshold switching voltage will switch the comparator off. A biasing circuit, connected to and controlling the comparator, temperature compensates the threshold switching voltage such that the threshold switching voltage changes proportionally to absolute temperature and controls a sensitivity of the threshold switching voltage to changes in a supply voltage of the circuit. In a preferred embodiment, the shunt is a portion of the printed board trace.

Abstract: An apparatus and a method for determining the water content of an oil-in-water emulsion is disclosed. The apparatus includes a first sensor for measuring the real part of specific admittance of the emulsion, a second sensor which acts as a temperature compensation device and electronic circuitry for producing a signal representative of the water content of the emulsion. The method for determining the water content comprises measuring the real part of specific admittance of an oil-in-water emulsion and providing a signal representative thereof, providing a reference signal indicative of the emulsion temperature, adjusting the measured real part of specific admittance signal with the reference signal and converting the adjusted signal into a current signal representative of the percentage water content of the emulsion.

Abstract: An electrical resistance corrosion probe incorporates a temperature sensitive resistor (RTD) that directly measures temperature of the probe and therefore of its environment as corrosion measurements are being made. The temperature sensitive resistor has one end connected to the common junction between the test and reference elements of the corrosion probe and has its other end connected in the common line to the several corrosion measuring circuits, including the test, reference and check circuits.

Abstract: In a method of diagnosing deterioration of a paint film, a probe is applied to the surface of a paint film. A voltage having a predetermined waveform is applied by a preamplifier across the probe and a base metal on which the paint film is formed. A current flowing through the paint film is measured by the preamplifier. An analog signal indicative of a measured current value is converted to a corresponding digital signal by an analog-to-digital converter. A personal computer operates to analyze the digital signal in accordance with a predetermined analyzing procedure so that the degree of deterioration of the paint film is determined. The resultant determination is displayed on the display.

Abstract: A dynamic strain measurement circuit includes a constant resistance conditioner. The constant resistance conditioner compensates for changes in lead wire resistance due to temperature. The conditioner includes adjustable resistance connected between a voltage supply and the strain gage. A potential difference is detected in the circuit and compared to a reference potential. Differences between the reference potential and the detected potential produce an error signal which is used to drive the control of the resistance value of the adjustable resistance in the measurement circuit.

Abstract: A pressure sensor circuit (10A) is disclosed which preferably utilizes a piezoresistive pressure transducer (11A) having a substantial temperature coefficient of resistance to provide an inherent temperature variation which is used to implement offset temperature compensation for the circuit. Two operational amplifiers (OA1, OA2) are configured along with selectable resistors (R.sub.1, R.sub.9, R.sub.7, R.sub.8, R.sub.5, R.sub.6 and R.sub.4) to implement four adjustments of the circuit (10A) to adjust span (gain), offset and temperature variation of both span and offset to achieve a desired result. All this is achieved while implementing a common mode gain for the circuit (10A) which is less than 5 and preferably no more than 2.

Abstract: A precision bridge measurement circuit connected to a current source providing a linear output voltage versus resistance change of a variable resistance (resistance temperature transducer) including a voltage follower in one branch of the bridge so that the zero setting of the transducer resistance does not depend upon the current source or upon an excitation voltage. The zero setting depends only on the precision and stability of the three resistances. By connecting the output of an instrumentation amplifier to a feedback resistor and then to the output of the voltage follower, minor nonlinearities in the resistance-vs-temperature output of a resistance-temperature transducer, such as a platinum temperature sensor, may be corrected. Sensors which have nonlinearity opposite in polarity to platinum, such as nickel-iron sensors, may be linearized by inserting an inverting amplifier into the feedback loop.

Abstract: A system and method for calibrating a transducer having a bridge-type network. The calibration includes a source of constant current and a calibration circuit including the source connected across one of the resistive-type transducer elements of the bridge. Switching means are provided in the calibration circuit so that the current can be selectively supplied to or withheld from the resistive-type transducer element across which the calibration circuit means is connected for producing a calibration signal. The calibration signal is substantially independent of the transducer output regardless of whether or not the signal is temperature compensated and whether it is switched mechanically, electromechanically, or electrically. An internal calibration resistor in the current source is used to make the current inversally proportional to the bridge arm resistance. The calibration resistor tracks the resistive-type transducer elements of the bridge over temprature.

Abstract: A circuit for measuring the internal resistance of a lambda probe 10 is provided with a junction device 16 for selectively loading the probe. Loading the probe via a junction device affords the advantage that an internal-resistance measurement can be effected in a simple manner within a very wide range of from several ohms up to several megaohms.

Abstract: Apparatus for indicating a predisposition to kidney stone disease in humans, and also dehydration, and for monitoring the efficacy of hydration therapy, comprises a conductivity probe including a tip which can be inserted into urine so that a drop thereof adheres to the tip, and display means for indicating the result as a derived function of conductivity (electrolyte concentration) in terms of urine specific gravity or osmolality. Preferably the probe electrodes are small and are spaced closely together so that the streamlines between the electrode tips are such that maximum current flows substantially within the adherent drop of urine.

Abstract: A method for detecting wear of a cutting tool for cutting a workpiece measures the contact resistance between the cutting tool and the workpiece for detecting wear of the cutting tool from a change in the contact resistance, whereby such wear of the cutting tool can be reliably and accurately measured.

Abstract: A heat radiating type liquid level sensor comprises a liquid level measuring resistor having a first temperature coefficient and an inverting amplifier gain of which is dependent on the change in resistance of an input resistor thereof. The input resistor has a second temperature coefficient. The liquid level measuring resistor and the input resistor are placed side by side so that the input resistor can experience the same ambient temperature as the liquid level measuring resistor.

Abstract: Method and apparatus for the real time detection of the formation of ice on a surface in which a sensor having spaced electrodes along the surface is embedded in the surface for which detection is to be provided. Resistance between the electrodes is monitored and electrode temperature is monitored. When a sharp rise in resistance on the surface due to the presence of ice is detected at the same time that the surface temperature is at or below the freezing temperature of water, then a computer provides a signal to indicate the formation of ice.