Abstract: A method of inspecting a test part is provided. The method includes positioning a coil on a surface of the test part and exciting the coil at a resonance frequency. The method also includes determining at least one of a resonance frequency shift and a quality factor of the coil and estimating an electrical conductivity of the test part based on at least one of the resonance frequency shift and the quality factor of the coil. The method further includes obtaining depth profile of residual stress using conductivity measurements at various resonance frequencies.

Abstract: A method of inspecting a test part is provided. The method includes positioning an eddy current probe on a surface of the test part and scanning the test part using the eddy current probe to generate a first signal corresponding to a no lift-off condition of the test part. The method further includes positioning the eddy current probe at a pre-determined distance from the surface of the test part and scanning the test part using the eddy current probe positioned at the pre-determined distance from the test part to generate a second signal corresponding to a lift-off condition of the test part. The method also includes processing the first and second signals to estimate an electrical conductivity of the test part.

Abstract: Method for removing air wave noise from shallow water controlled source electromagnetic survey data, using only the measured data and conductivity values for sea water (140) and air. The method is a calculation performed numerically on CSEM data and resulting in an estimate of those data that would have been acquired had the water layer extended infinitely upward from the seafloor. No properties of the sub-sea sediments are used. Synthetic electromagnetic field data are generated for (a) an all water model (141) and (b) an air-water model (146-147) of the survey region. These simulated results are then used to calculate (148-150) electromagnetic field values corresponding to a water-sediment model with water replacing the air half space, which represent measured data adjusted to remove air wave noise.

Abstract: A coil for use in an eddy current sensing probe is formed through depositing film traces. The film traces can be directly deposited. The film traces can be deposited on the outer surface of a core or on ends of the core. The film traces can be deposited onto non-planar surfaces other than cores for the inspection of parts having complex geometries. The coil can be used in a single coil probe or in a probe having a sensor array.

Abstract: Inconsistencies in a reinforced resin matrix part are detected using an inductive coupling probe connected with or part of a tuned resonant circuit. An alternating magnetic field produced by the probe is coupled to the part and produces eddy currents in the part. Inconsistencies in the part result in changes in the complex impedance and/or resonance of the circuit which are detected by a network analyzer.

Abstract: On a friction stir spot welded workpiece having a first side including a friction stir spot weld hole and an opposing smooth second side, an eddy current probe is passed over the spot weld hole from the second side, and an eddy current signal representative of a material thickness of the workpiece is produced. The eddy current is analyzed via an eddy current analyzer, and a graphic representation of the analyzed eddy current signal is monitored as the probe passes over the spot weld hole, and a local minima of the graphic representation defined by a displayed characteristic J-shaped curve is identified, the local minima defining a remaining material thickness of the workpiece at the bottom of the spot weld hole. From the graphic representation, a value of the remaining material thickness is determined, and a weld strength of the spot weld as a function of the remaining material thickness is determined.

Abstract: Methods and apparatuses are provided for calibrating eddy current sensors. A calibration curve is formed relating thickness of a conductive layer in a magnetic field to a value measured by the eddy current sensors or a value derived from such measurement, such as argument of impedance. The calibration curve may be an analytic function having infinite number terms, such as trigonometric, hyperbolic, and logarithmic, or a continuous plurality of functions, such as lines. Such curves can reduce the number of wafers used in the calibration of the sensors while providing higher accuracy over a larger thickness range. High accuracy allows the omission of optical sensors, and use of eddy current sensors for endpoint detection, transition call detection, and closed loop control in which a process parameter is changed based on the measured magnetic flux density change in one or more processing zones.

Abstract: The present invention relates to a method for evaluating the SOI wafer in a method for evaluating an SOI wafer in which a sheet resistance of a buried diffusion layer of an SOI wafer that has at least an SOI layer on an insulator layer and has a buried diffusion layer whose impurity concentration is higher than other region of the SOI layer in an interface area with the insulator layer of the SOI layer is evaluated, the method including the steps of measuring a sheet resistance of the whole SOI layer or the whole SOI wafer, and estimating the sheet resistance of the buried diffusion layer by assuming respective layers that compose the SOI wafer to be resistors connected in parallel and converting the measured result of the sheet resistance measurement. As a result of this, there is provided a method for evaluating the SOI wafer that can directly measure the SOI wafer itself to be the product to thereby evaluate the sheet resistance of the buried diffusion layer thereof, without fabricating a monitor wafer.

Abstract: An IBOC broadcasting receiver that uses two different bit error rates as threshold values in receiving hybrid broadcasting in a simultaneous broadcasting format, and switches between digital broadcasting reception and analog broadcasting reception based on the two threshold values. The IBOC broadcasting receiver counts the number of occurrences of switching between digital broadcasting reception and analog broadcasting reception in a specified period of time, and increases a hysteresis width between the two threshold values when the number of occurrences of switching counted exceeds a specified number.

Abstract: A method of inspecting a test part is provided. The method includes positioning a coil on a surface of the test part and exciting the coil at a resonance frequency. The method also includes determining at least one of a resonance frequency shift and a quality factor of the coil and estimating an electrical conductivity of the test part based on at least one of the resonance frequency shift and the quality factor of the coil. The method further includes obtaining depth profile of residual stress using conductivity measurements at various resonance frequencies.

Abstract: The present invention generally relates to the field of biomolecule detection. More specifically, the present invention relates to compositions, methods and systems for the detection and manipulation of biomolecules using magnetic particles.

Abstract: A transparent conductive film roll which has a transparent conductive layer on at least one surface thereof and has an excellent distribution uniformity of surface resistance in longitudinal and lateral directions thereof wherein the distribution uniformity D of surface resistance defined by the following expression (1) is 0.2 or less when the surface resistance of the transparent conductive layer is measured at a total of 33 points within the film roll, and therefore, is suitable especially for a large panel, D=(Rmax?Rmin)/(Rmax+Rmin)??(1) where Rmax and Rmin represent the maximum and minimum values of 33 surface resistance measurement values.

Abstract: A method of inspecting a test part is provided. The method includes positioning an eddy current probe on a surface of the test part and scanning the test part using the eddy current probe to generate a first signal corresponding to a no lift-off condition of the test part. The method further includes positioning the eddy current probe at a pre-determined distance from the surface of the test part and scanning the test part using the eddy current probe positioned at the pre-determined distance from the test part to generate a second signal corresponding to a lift-off condition of the test part. The method also includes processing the first and second signals to estimate an electrical conductivity of the test part.

Abstract: A rotating head for a device for the nondestructive testing of metallic test specimens has probe carriers, stray flux or eddy current sensors, a coupling ring and elastic coupling elements. In this way, tandem-like, roughly forced coupling of the pivoting motions of the probe carriers is produced.

Abstract: The present invention relates to a magnetic induction tomography system and method for studying the electromagnetic properties of an object. In order to provide a high resolution MIT technique without the need of increasing the number of coils, a magnetic induction tomography system (1) for studying the electromagnetic properties of an object (2) is suggested, the system comprising one or more generator coils (4) adapted for generating a primary magnetic field, said primary magnetic field inducing an eddy current in the object (2), one or more sensor coils (5) adapted for sensing a secondary magnetic field, said secondary magnetic field being generated as a result of said eddy current, and means (6, 7, 8, 9) for providing a relative movement between one or more generator coils (4) and/or one or more sensor coils (5) on the one hand and the object (2) to be studied on the other hand.

Abstract: Inconsistencies in a reinforced resin matrix part are detected using an inductive coupling probe connected with or part of a tuned resonant circuit. An alternating magnetic field produced by the probe is coupled to the part and produces eddy currents in the part. Inconsistencies in the part result in changes in the complex impedance and/or resonance of the circuit which are detected by a network analyzer.

Abstract: A method of determining a mass variation of a conductive film on a substrate with an area, an edge zone, and a center zone, is disclosed. The method includes providing a measured conductive film mass of a conductive film on a substrate. The method also includes positioning a sensor near a set of positions on the substrate; measuring using the sensor a set of electrical responses; and correlating the set of electrical responses to a set of conductive film thicknesses. The method further includes estimating a volume of the conductive film based at least in part on the set of conductive film thicknesses and the area; and estimating a derived conductive film mass based in part on the volume and a conductive film density, wherein the mass variation is a difference between the measured conductive film mass and the derived conductive film mass.

Abstract: A seal inspector and a method of inspecting a seal are described. A seal inspector includes an eddy current sensor for detecting changes in an eddy current within a lid seal of a can. The eddy current sensor includes a signal line for creating a magnetic field, which induces the eddy current. The induced eddy current generates a magnetic field that acts on the alternating current and as a consequence produces an eddy current response. A signal processing control unit receives the eddy current response and determines whether a value associated with the eddy current has surpassed a threshold value. If the associated value has surpassed the threshold value, the can may be ejected from a can conveyor system.

Abstract: In an ultrasonic flow meter for measuring a flow rate of a fluid flowing through a conduit by detecting a propagating time difference between a forward propagating time of an ultrasonic wave propagating within the conduit in a forward direction and a backward propagating time of an ultrasonic wave propagating within the conduit in a backward direction, forward and backward ultrasonic wave signals generated by ultrasonic vibrating elements are sampled to derive forward and backward digital data series x and y, which are stored in a memory, the forward and backward digital data series x and y are read out of the first and second memory units and total sums of absolute difference values between the forward and backward digital data series x and y are calculated, while data positions of these backward and forward digital data series x and y are relatively shifted, a shift amount of data positions at which a total sum of absolute difference values becomes minimum is detected, an ultrasonic propagating time differe

Abstract: Local features such as cracks in materials are nondestructively characterized by measuring a response with an electromagnetic sensor and converting this response into a selected property using a database. The database is generated prior to data acquisition by using a model to generate a baseline response or field distribution for the sensor and combining these results with another model, which may be simpler than the first model or provide a local representation of the field perturbations around a feature, which is evaluated multiple times over a range of values of the selected property. In addition, the presence of a feature may be detected by converting the sensor response into a reference parameter, such as a lift-off factor that reflects the sensor position relative to a material edge, and using this parameter to determine a reference response that can be compared to the measured response.

Abstract: A method and related apparatus for non-contact measurement of electrical conductivity of powder-like materials using eddy currents includes the steps of placing a powder to be measured in a hollow dielectric sampling container, the sampling container disposed and freely axially moving within an outer dielectric housing. An eddy-current sensor including a winding is arranged on an outside surface of the housing. Current is forced in the winding to excite the powder to generate eddy currents. The introduced active resistance is measured at the eddy-current sensor and an electrical conductivity of the powder is determined using the measured active resistance. The powder is preferably vibration compacted and the density and electrical conductivity determined at a plurality of stages during the vibration compacting step.

Abstract: An inspection device for performing nondestructive testing on a test subject includes a manually controlled inspection cart. The inspection device also includes a nondestructive testing platform and a computer coupled to the inspection cart. The computer is operable to control the movement of the nondestructive testing device when the inspection device is within a predetermined distance from the test subject.

Abstract: An eddy current detection system configured in accordance with an example embodiment of the invention employs a high frequency rotary eddy current probe that is capable of detecting very shallow surface imperfections, including imperfections originating at scribe lines located near lap joints on an aircraft fuselage. The rotary eddy current probe includes a differential sensing coil arrangement surrounded by a reflection coil, both of which are located within the probe tip housing of the rotary eddy current probe. The differential sensing coil arrangement and the reflection coil are positioned off-axis within the rotary eddy current probe. In addition, the rotary eddy current probe employs a partial electromagnetic shield that does not completely surround the differential sensing coil arrangement.

Abstract: A sensor body for use in a pig for determining characteristics of a pipeline wall though which the pig passes includes a circuit board and a single coil wrapped around the circuit board. A microcontroller is mounted to the circuit board and connected to the single coil and configured to induce a waveform on the coil to thereby create an eddy current in the pipeline wall adjacent the sensor body. The microcontroller is also configured to measure changes in a characteristic of the induced waveform on the single coil that correspond to the presence of anomalies on an inside diameter of the pipeline wall. The sensor body also includes a sensor body cover molded about the circuit board, the microcontroller and the single coil. The sensor body cover consists essentially of a wear resistant, non-conductive material that includes a polymer material.

Abstract: A method for determining a power flow in a distribution network includes the step of determining an admittance matrix for a circuit that includes a floating transformer in an electrical power distribution system. The admittance matrix includes an admittance of a fictitious shunt connected between a non-grounded winding of the floating transformer and ground. The method also includes the step of obtaining real time power measurements from a portion of the electrical power distribution system including the floating load transformer. The method further includes solving the power flow using the admittance matrix and the real time power measurements.

Abstract: The subject apparatus and method measures the Total Average Power Loss and isolates the different power loss components of Total Average Loss such as Ton Loss and Toff loss at switching devices such as, MOSFETs, BJTs and IGBTs that may be used in a switching power supply. It provides separation of the components of Total Average Loss as Turn Ton Loss, Turn Toff Loss and allows derivation of conduction loss. It also has the capability to measure Total Average Loss and Switching Loss, while amplitude, duty cycle and frequency of the switching signal is varying in a switching power supply.

Abstract: Testing a transformer by applying to the transformer a test signal, the frequency of which may be lower than the nominal frequency of the transformer. The voltage of the test signal may also be lower than the nominal voltage of the transformer. A number of frequency-dependent parameters are measured, particularly the eddy current resistance and the hysteresis curve of the transformer, in order to derive a simulation model which simulates the behavior of the transformer at different frequencies. Using this simulation model, it is possible to predict operating parameters of the transformer, such as the terminal voltage on the secondary and the terminal current in the secondary, during operation with a frequency deviating from the frequency of the test signal, particularly during operation with the nominal frequency of the transformer.

Abstract: A non-contact printed circuit board (PCB) electromagnetic testing system comprises at least one high resolution transducer operative to induce multi-frequency, multi-amplitude eddy currents in a tested PCB, each such transducer including both a high frequency excitation coil that serves also as a sensing coil and a direct current (DC) bias coil operative to provide an optimal transducer operating regime; a multi-frequency generator for providing AC and DC bias signals to each transducer; and a control mechanism for driving the transducer. Optionally, the system further comprises an external ferrite concentrator that enhances a magnetic field flux focus and depth of focus on the inspected PCB. The multi-frequency, multi-amplitude methods enable three-dimensional mapping of various features in the PCB with both high sensitivity and high resolution in respective operating regimes.

Abstract: A coin discriminator has a coin path along which a coin, containing a first portion and a second portion made of different metals and/or metal alloys, is arranged to pass. An electrical mechanism supplies time-varying drive signals to the coil mechanism. A detection mechanism detects eddy currents induced in the coin by the coil mechanism. The coil mechanism is arranged to induce in the coin an eddy current loop, which in a predetermined region of the coin crosses a bond between the first and the second portions of the coin.

Abstract: A digital eddy current proximity system including a digital impedance measuring device for digitally measuring the proximity probes impedance correlative to displacement motion and position of a metallic target object being monitored. The system further including a cable-length calibration method, an automatic material identification and calibration method, a material insensitive method, an inductive ratio method and advanced sensing characteristics.

Abstract: A signal processor, for use with a zero crossing module of a vortex flow meter, includes a peak amplitude detector, a comparator, and a filter module. The filter module is enabled when the comparator determines that the amplitude is less than a low flow rate threshold. The filter module filters a vortex signal and the filtered signal is provided to a frequency estimator that uses a zero crossing algorithm. The signal processor may increase the signal-to-noise ratio at low flow rates for which the frequency estimator may not otherwise be able to accurately estimate the flow rate. Low flow rates may be measured by determining that there is a low flow rate using amplitude detection of a vortex signal, filtering the vortex signal based on the amplitude detection, and using a zero crossing algorithm on the filtered vortex signal.

Abstract: An automated tool for performing an EL CID inspection of the step iron region of a generator stator that can be employed with the rotor in place. The tool has a track that is axially cantilevered at one end and supported magnetically within a stator slot adjacent the region to be monitored. The track has a smoothly rounded contour that approximately conforms to the profile of the stator step region. A carriage carrying a pickup coil is slideably mounted on the track and is driven back and forth along the track over the area to be inspected by a remotely-operated drive system. A video camera is mounted on the track and provides a remote visual indication of the location of the carriage relative to the stator.

Abstract: A method of predicting the performance of certain electromagnetic devices is based on the integrated average core loss (IACL) and the integrated average relative permeability (IAP) of the electromagnetic core material used in the devices. The method includes the steps of establishing the range of induced magnetic fields over which the device is designed to operate, measuring the core loss and relative permeability of the core material over the range of induced fields and calculating the IACL and IAP over the range. Performance parameters can then be predicted using equations based on the IACL and the IAP with coefficients and constants derived through linear regression analysis.

Abstract: Methods are described for the use of conformable eddy-current sensors and sensor arrays for characterizing residual stresses and applied loads in materials. In addition, for magnetizable materials such as steels, these methods can be used to determine carbide content and to inspect for grinding burn damage. The sensor arrays can be mounted inside or scanned across the inner surface of test articles and hollow fasteners to monitor stress distributions. A technique for placing eddy-current coils around magnetizable fasteners for load distribution monitoring is also disclosed.

Abstract: A reference standard and method for inspecting dual-layered coatings. The reference standard has a first layer adherent to a substrate, the first layer has a predetermined thickness that increases in one direction. Adherent to the first layer is a second layer, the second layer has a predetermined thickness that increases in a direction orthogonal with the first layer. The orientation of the first and second layers of the reference standard provides a spectrum of the possible variations of the dual-layered coating.

Abstract: An inspection apparatus for inspecting welds in a nuclear reactor jet pump includes a probe subassembly rotatably and linearly movably coupled to a frame structure configured to attach to a top flange of the reactor pressure vessel. The probe subassembly includes a plurality of probe arms pivotably coupled to a housing, with each probe arm including a sensor. The probe arms are pivotably movable between a first position where the probe arms are parallel to a longitudinal axis of the probe subassembly, and a second position where the probe arms are at an angle to the longitudinal axis of the probe subassembly. An insertion subassembly couples to the jet pump suction inlet. The insertion subassembly is sized to receive the probe subassembly and guide the probe subassembly into the jet pump through the jet pump suction inlet.

Abstract: The sheet resistance meter has: a coil which produces a magnetic field; a sensor head provided to enable the magnetic field to induce eddy currents in a thin film formed on a substrate so that the lines of a magnetic force exerted by the magnetic field extend on one side of the substrate; a control device for detecting the sheet resistance of the thin film according to a variation of the magnetic field caused by the eddy currents; a capacitor for achieving resonance with the coil; and a groove section, a primary air port, an auxiliary air port, and a side air port, provided in the sensor head, for controlling the temperature of the coil. The arrangement stabilizes results of the measurement of a sheet resistance by a sheet resistance meter of a one-sided eddy current detection type when it is used continuously.

Abstract: A high frequency magnetic properties measuring system is used for measurement of high frequency magnetic properties, for example high frequency core-loss and magnetic hysteresis curve (coercivity force, magnetic flux density, permeability) in soft magnetic materials such as ferrites, permalloy and amorphous magnetic cores used in inductors, transformers and filters of various electric and electromagnetic systems and devices such as computers and multimedia devices. A digital oscilloscope is operated as a waveform detection unit for measuring magnetic fields and magnetic flux density. A signal generator and a power amplifier are operated as a signal input unit. The digital oscilloscope and the signal generator are remotely controlled through a General Purpose Interface Bus by the computer. The high frequency magnetic properties are measured by remote control and the resulting data can be outputted and stored by the computer.

Abstract: A magnetic inspection head adapted for use with samples having non-planar surfaces. A magnetically permeable core has a pair of poles joined by a magnetically permeable bridge to form a closed magnetic circuit between the pole legs, bridge and the test material. Each pole has magnetically permeable support means terminating in a magnetically permeable deformable surface for engaging the sample. The support means is yieldable such that when the inspection head is placed in contact with the irregular surface of the sample, the deformable surface is deformed to accommodate the shape of the sample with minimal air gaps therebetween. Preferably, the deformable surface is provided by a plurality of pins slidably engaged in a pole structure and urged outwardly for contact with and conformance with a non-planar sample surface.

Abstract: A method and apparatus are disclosed for measuring the magnetic properties of magnetic materials by generating flux lines through a balanced magnetic core and through a magnetic sample placed adjacent to the core. Increased sensitivity is accomplished through a modulation of the flux in the magnetic core which is measured and subsequently demodulated to yield an electrical signal corresponding to the magnetic properties of the material being tested.

Abstract: A method of primary recrystallization annealing grain-oriented electrical steel strip comprises the steps of conducting online measurement of the primary recrystallization grain diameter of the steel after primary recrystallization annealing and, based on the result of this measurement, controlling the primary recrystallization grain diameter of the steel after primary recrystallization annealing by varying either or both of the annealing temperature and the pass velocity during the primary recrystallization annealing. The method enables stable production of grain-oriented electrical steel strip exhibiting good secondary recrystallization and excellent electrical properties.

Abstract: A device for the determination of residual stress in a material sample consisting of a sensor coil, adjacent the material sample, whose resistance varies according to the amount of stress within the material sample, a mechanical push-pull machine for imparting a gradually increasing compressional and tensional force on the material sample, and an impedance gain/phase analyzer and PC for sending an input signal to and receiving an input signal from the sensor coil. The PC will measure and record the change in resistance of the sensor coil and the corresponding amount of strain of the sample. The PC will then determine from the measurements of change of resistance and corresponding strain of the sample the point at which the resistance of the sensor coil is at a minimum and the corresponding value and type of strain of the sample at that minimum resistance point thereby enabling a calculation of the residual stress in the sample.

Abstract: Permeameter suited for measuring permeability of a small, non-magnetic (i.e., the permeability value is close to 1) object. The probe of the permeameter is of the differential transformer type with an exciting coil and two detecting coils placed at both ends of the exciting coil. The difference in the outputs of the detecting coils is analyzed and the effect of the eddy current is effectively eliminated, whereby the signal representing the permeability of the object is extracted from the difference signal by the phase shift analysis. By reducing the distance between the two detecting coils, the influence of the disturbance of the eddy current at the boundary of the object sample is minimized and the permeameter can measure a small object sample without sacrificing accuracy and sensitivity.

Abstract: A tool dullness indicator and method comprising the measurement of eddy currents at a known, controlled frequency directly in the tool by measuring the phase angle shift in a coil when a sample is put into or next to the coil. The phase angle change caused by presence of a workpiece is measured when the tool is sharp to provide a reference reading taking into account the surface hardness and other bulk properties of the workpiece, and arriving at a parameter that is dependent on eddy current changes, such as phase angle shift or other measurable changes related to eddy currents in the part, and then analyzing the workpiece, either while working, or at a set programmed check time to determine when the tool is dull as a function of the change in eddy current characteristics caused by work hardening.

Abstract: A novel method and system for measuring AC magnetic characteristics is disclosed, in which the loss of a magnetic core is measured by defining the change rate of magnetic flux density, and for this purpose, the duration of a voltage induced in the coil of an object magnetic core during the gate period is detected and controlled by an input voltage, a reset current and a load resistor.

Abstract: The invention is concerned with a method and apparatus for measuring magnetic losses in a ferromagnetic material specimen. According to the invention, an alternating magnetic field having a predetermined frequency and an amplitude which is modulated at a frequency lower than the predetermined frequency is applied to the specimen, and a temperature modulation at a surface of the specimen having the applied field is measured. The magnitude of magnetic losses in the specimen is determined from the measured surface temperature modulation. The method and apparatus of the invention do not necessitate winding coils around the ferromagnetic material specimen, and also enable one to obtain information about the distribution of magnetic losses in the specimen.

Abstract: A local coil assembly for use in NMR imaging includes a base which supports a pair of spaced local coil modules. The size and separation of the local coil modules can be changed without affecting the resonant frequency of the assembly. Each local coil module includes a pair of loop-gap resonators, and the base provides the electrical interconnection of the loop-gap resonators in each module.

Abstract: An inductive sine wave oscillator circuit for an eddy current proximeter. The oscillator circuit includes an operational amplifier and a coil. The frequency and amplitude of the output signal produced by the circuit varies with and is controlled by the inductance of the coil. The circuit signal input to the operational amplifier undergoes a phase shift as the signal passes through the amplifier. One advantage of the oscillator circuit is that the frequency and amplitude of the output signal of the circuit for a coil having a particular inductance remains relatively stable and constant when the operating temperature of the coil varies. In addition, the coil can be fabricated from a material having a relatively high electrical resistivity.

Abstract: A core loss tester employs separate cables for excitation and pickup. Testing is performed at a fixed flux density in the ferromagnetic core. A processing circuit on the output of the pickup coil scales the voltage developed so that, when excitation current is increased so that the indicated output of the pickup coil equals the effective cross-sectional area of the flux path, the fixed predetermined value of flux density is produced. When this condition is achieved, the excitation current times the sensed flux-induced voltage provides a measurement of the core loss in watts. Excitation is accomplished with a multi-conductor cable looped once or more times through the core with the conductors in the cable connected in series by mating together of a connector at each end.

Abstract: A self inverting gauging system for such parameters as capacitively sensed distance or inductively sensed resistivity in which the sensor provides an output inversely varying with the dimension of interest. The gauge typically includes a dual slope integrator responsive to a reference value on the up integration and to the sensor output on the down integration. The interval of the down integration necessary to reset the integrator to the original value varies directly, rather than inversely, with the dimension of interest and is typically provided as the digital output indication of a counter. In the application to resistivity gauging, the up integration reference signal is preferably provided by the output of a thickness gauge such that the ultimate counter display represents element resistivity compensated for thickness.