Abstract: To measure the resistance area product of a high resistivity layer using a microscopic multi point probe, the high resistivity layer is sandwiched between two conducting layers. A plurality of electrode configurations/positions is used to perform three voltage or resistance measurements. An equivalent electric circuit model/three layer model is used to determine the resistance area product as a function of the three measurements.

Abstract: A method may comprise: controlling ON/OFF switching of a power switch via a driver circuit; receiving a first signal on a detection pin associated with the power switch, wherein the first signal corresponds to a first point in time when current is not passing through the power switch and wherein the first signal indicates a first voltage drop over one or more other circuit elements; receiving a second signal on the detection pin, wherein the second signal, wherein the second signal corresponds to a second point in time when current is passing through the power switch and wherein the second signal indicates a voltage drop over the power elements; and determining the voltage drop over the power switch based on a difference between the first signal and the second signal.

Abstract: An apparatus for forming an anchor to connect a fiber to an explosive charge wall includes an anchor insert tab disposed on the interior side of the wall, a top plate disposed on the exterior side of the wall, an ST connector disposed on the exterior side and attached to the top plate to position the ST connector at the fiber insert wall opening for receiving the fiber, a plurality of zip ties extending through the anchor insert tab, the wall, and the top plate, and a plurality of locking members one for each of the zip ties. The zip ties each have a locking head disposed on the interior side of the wall to press the anchor insert tab against the interior wall surface. The locking members are engaged with the zip ties to press the top plate against the exterior wall surface to form the anchor.

Abstract: A device comprises at least one pair of excitation electrodes forming a capacitor; a floorplan (e.g., a ground plane); and an electronic circuit. The device comprises at least one control electrode arranged at a distance from the capacitor. A switching circuit, of the device, comprises a switch having an open state and a closed state. The switching circuit is designed to apply, to the control electrode, an electric potential common to the floorplan when the switch is in the closed state. The switching circuit is also designed to leave a floating electrical potential for the control electrode when the switch is in the open state. The electronic circuit is designed to measure the mutual capacitance between the pair of excitation electrodes when the switch is in the open state and when it is in the closed state.

Abstract: To provide a measuring apparatus that can detect a wide range of capacitance values with high sensitivity.

Abstract: Disclosed is a method of determining subsurface temperatures of a surveyed region. The method comprises using a transmitter to transmit a pulsed electromagnetic signal into the ground; using a receiver to detect a return signal following interaction of said transmitted signal with features of the subsurface and determining one or more temperatures within the subsurface from the return signal. The temperature may be determined from a dielectric constant of a subsurface region, as determined from the received signal.

Abstract: The present disclosure provides a microfluidic device and system for measuring a composite electropharyngeogram (EPG) signal from a pool of multiple nematodes, wherein the composite EPG signal is measured from the pool of nematodes present in a single recording channel connected to two or more integrated electrodes. The microfluidic device includes an inlet port and outlet port directly connected to a single recording channel and two or more electrodes directly connected to the recording channel. The recording channel is configured to hold 10 to 10,000 nematodes.

Abstract: A device is provided for electrically measuring surface characteristics of a sample. The device comprises at least one group of three electrodes: a first and second electrode spaced apart from each other and configured to be placed onto the surface of the sample, and a third electrode between the first two but isolated from these two electrodes by a one or more first insulators, wherein a second insulator further isolates the central electrode from the sample when the device is placed thereon. The three electrodes and the insulators are attached to a single or to multiple holders with conductors incorporated therein for allowing the coupling of the electrodes to power sources or measurement tools. The placement of the device onto a semiconductor sample creates a transistor with the sample surface acting as the channel. The device thereby allows the determination of the transistor characteristics of the sample in a straightforward way.

Abstract: Apparatuses of a noise measurement system and methods for using the same are disclosed. In one embodiment, a noise measurement system may include a plurality of probe groups electrically coupled to a plurality of DUTs, where a probe group in the plurality of probe groups includes multiple channels, and where the multiple channels of each probe group are bundled as a group for reducing electromagnetic interference among the plurality of probe groups, and wherein the group is shielded from corresponding signal groups of other DUTs with a connection to a circuit ground of the noise measurement system for reducing ground loop generated signal interference. The noise measurement system may further include a controller configured to perform noise measurement.

Abstract: The disclosure relates to a method for monitoring the performances of a cable for carrying a downhole assembly in a wellbore, the cable having at least a conductive core and an insulating outer layer, the method including: performing on the cable a detection operation for detecting the presence of local anomalies of the cable; generating an electrical model of a predetermined configuration of an installation including the cable and the downhole assembly disposed in the wellbore, the model being defined in function of the detected local anomalies, estimating a parameter relative to a signal transmitted by the cable between the downhole assembly and a surface equipment in the predetermined configuration on the basis of the electrical model.

Abstract: A magnetic image sensor is provided. The magnetic image sensor includes: a magnetic resistance (1), arranged along a scanning direction and configured to detect a changed magnetic signal in a range to be detected; a configuration resistance (2), connected with the magnetic resistance (1), wherein a resistance value of the configuration resistance (2) is adjustable; and a driving circuit (3), connected with the magnetic resistance (1) and configured to perform output control on the changed magnetic signal detected by the magnetic resistance (1) The problem of relatively stronger noise signal caused by a magnetic resistance deviation of a magnetic image sensor is solved.

Abstract: A system and method verifies continuity with and measures voltage across a circuit under test (in some instances simultaneously) using two or more test probes. Two or more probe continuity circuits measure continuity through the test probes by injecting a test current through and measuring a processed test current received at each of the plurality of test probes. The probe continuity circuits measure the respective processed test current rendered by the test current flowing through the test circuit at each test probe. A voltmeter measures the potential difference across the test probes.

Abstract: A diagnostic device (40) having layers (25, 27, 29) corresponding to respective layers (24, 26, 28) of a given photovoltaic module (20). The diagnostic device is provided for testing and monitoring a condition of the given photovoltaic module. The layers of the diagnostic device may be made of respective materials with the same or substantially the same electrical resistance and aging characteristics as the respective layers of the given photovoltaic module under operational conditions. Electrodes (42, 44, 50A-C, 52A-C, 54A-C) of the diagnostic device are configured to independently measure electrical resistance along at least two different current resistance paths in the diagnostic device corresponding to respectively different current leakage paths (R1, R?1, R2-4, R5, R5) of the given photovoltaic module.

Abstract: A system for measuring and mapping sheet resistivity of the film on flat-panel has a frame, a collection of leveling chucks, a probe-mounting assembly, and a collection of four-point probes. The probe-mounting assembly is a frame that holds the four-point probes in place. The leveling chucks and the probe-mounting assembly are mounted onto the frame, within the probe chamber. The flat panel is positioned in between the probe-mounting assembly and the leveling chucks. The sheet resistivity measurement by each of the collection of four-point probes can be done by electrical switching instead of mechanical repositioning and the flat panel transportation to and from the measurement position only needs to be done in one round trip instead of two, thus much time is saved. Also, the leveling chuck's speed in pressing the flat panel against the collection of four-point probes can be well controlled to avoid damaging of the flat panel.

Abstract: Systems and methods of designing geometry of a tool set in a numerical simulation of sheet metal forming operations including springback compensation are disclosed. Computerized die face model representing an initial geometry of a tool set is generated for forming a sheet metal work-piece to a part's desired geometry. Numerically-simulated deep drawing operation, optional trimming operation and a springback effect are conducted to obtained a trial geometry of the part. A deviation between the trial geometry and the desired geometry is obtained. When the deviation is outside of tolerance, computerized die face model is regenerated according to a modified geometry of the tool set that includes an estimated amount of springback compensation derived from the deviation due to springback together with a node adjustment scheme for ensuring model conformity along the boundary line. Final modified geometry of the tool set is iteratively obtained.

Abstract: A method of imaging electrical conductivity distribution of a subsurface containing metallic structures with known locations and dimensions is disclosed. Current is injected into the subsurface to measure electrical potentials using multiple sets of electrodes, thus generating electrical resistivity tomography measurements. A numeric code is applied to simulate the measured potentials in the presence of the metallic structures. An inversion code is applied that utilizes the electrical resistivity tomography measurements and the simulated measured potentials to image the subsurface electrical conductivity distribution and remove effects of the subsurface metallic structures with known locations and dimensions.

Abstract: The present disclosure relates to a sheet resistance measuring method, comprising the following steps: connecting at least one to-be-measured thin film having a predetermined shape to two separate electrodes in at least one pair of electrodes; measuring the resistance between the two electrodes in each pair of electrodes; and determining the sheet resistance of the to-be-measured thin film based on the measured resistance and the shape of the corresponding to-be-measured thin film.

Abstract: A method includes probing at least one semiconductor fin using a four-point probe head, with four probe pins of the four-point probe head contacting the at least one semiconductor fin. A resistance of the at least one semiconductor fin is calculated. A carrier concentration of the semiconductor fin is calculated from the resistance.

Abstract: Devices and methods for testing the operation of acoustic devices such as ultrasonic probes. The disclosed devices and methods identify failures of individual piezoelectric elements of various types of ultrasonic probes free of family-specific adapters to interface with such probes and free of acoustic coupling fluids or the like to establish acoustic coupling with the probes. In one arrangement, a testing appliance is disclosed that includes a testing unit and first and second probes electrically connected thereto. After an operator has established electrical connections between the first probe and a first contact of a connector assembly of the acoustic probe and between the second probe and a ground return path of the connector assembly, the testing device may pass a current through an electric circuit between the first and second probes and determine one or more corresponding electrical quantities of the circuit for establishing statuses of the probe.

Abstract: A regulated, power supply system is described using multiphase DC-DC converters with dynamic fast-turnon, slow-turnoff phase shedding, early phase turn-on, and both load-voltage and drive-transistor feedback to pulsewidth modulators to provide fast response to load transients. In an embodiment, a system master can automatically determine whether all, or only some, slave phase units are fully populated. The programmable system includes fault detection with current and voltage sensing, telemetry capability, and automatic shutdown capability. In an embodiment, these are buck-type converters with or without coupled inductors, however some of the embodiments illustrated include boost configurations.

Abstract: A probe card 10 includes a first probe 11 configured to come into electric contact with an emitter electrode of a power device D; a block-shaped first connecting terminal 12 to which the first probe 11 is connected; a second probe 13 configured to come into electric contact with a gate electrode of the power device D; a block-shaped second connecting terminal 14 to which the second probe 13 is connected; a contact plate 15 configured to come into electric contact with a collector electrode of the power device D; and a block-shaped third connecting terminal 16 fixed to the contact plate 15. Further, the first connecting terminal 12, the second connecting terminal 14 and the third connecting terminal 16 electrically come into direct contact with corresponding connection terminals of a tester, respectively.

Abstract: A method of generating a capacitance-voltage (C-V) characteristic for a discrete device formed within a semiconductor structure may include exposing first and second contact regions associated with the discrete device, coupling a high-frequency impedance probe having a frequency range of about 5 Mhz to about 110 Mhz to an impedance analyzer, and coupling the high-frequency impedance probe to a first and a second atomic force probe tip. Using an atomic force microscope, the first atomic force probe tip is coupled to the exposed first contact region and the second atomic force probe tip is coupled to the exposed second contact region. The C-V characteristic for the discrete device is then measured on the impedance analyzer, whereby the impedance analyzer applies an operating frequency corresponding to the frequency range of about 5 Mhz to about 110 Mhz to the first and second contact regions of the discrete device using the high-frequency impedance probe.

Abstract: Various exemplary embodiments provide probes, systems and methods for measuring an effective electrical resistance/resistivity with high sensitivity. In one embodiment, the measuring system can include an upper probe set and a similar lower probe set having a sample device sandwiched there-between. The device-under-test (DUT) samples can be sandwiched between two conductors of the sample device. Each probe set can have an inner voltage sense probe coaxially configured inside an electrically-isolated outer current source probe that has a large contact area with the sample device. The measuring system can also include a computer readable medium for storing circuit simulations including such as FEM simulations for extracting a bulk through-plane electrical resistivity and an interface resistivity for an effective electrical z-resistivity of the DUT, in some cases, having sub-micro-ohm resistance.

Abstract: An apparatus for measuring electrical parameters for an electrical system measures a first and second parameters of the electrical system between connections to the electrical system. A processor determines a third electrical parameter of the electrical system as a function of the first parameter and the second parameter. Wireless communication is provided between components of the apparatus.

Abstract: A chip on glass substrate includes a substrate, first, second, and third pads that are arranged on the substrate and that are electrically connected to an IC device, and first to fourth conductive patterns. A first conductive pattern is arranged on the substrate, has one end electrically connected to the first pad, and has another end that is electrically floated. Second and third conductive patterns are arranged on the substrate, each have one end electrically connected to the second pad, and each have another end that is electrically floated. A fourth conductive pattern is arranged on the substrate, has one end electrically connected to the third pad, and has another end that is electrically floated.

Abstract: A probe module for testing an electronic device comprises at least two contacts, each contact including a first end portion extending in a first direction along a first line, a second end portion extending linearly in a second direction opposite from the first direction and along a second line, and a third curved portion extending between the first end portion and the second end portion. The first line is spaced apart from and in parallel with the second line, and the at least two contacts are spaced apart from each other in a direction perpendicular to the first line and the second line. Methods for making such a probe module are also taught.

Abstract: A resistance measuring apparatus includes: a voltage injector that injects an AC signal into a circuit by applying an AC voltage to an injection coil; a current measuring unit that measures an AC current produced in the circuit by the injection coil using a detection coil; a processing unit that calculates the circuit resistance from the AC signal voltage and the measured AC current; and a reference signal generator that outputs a binary reference signal that has a same period as the AC voltage and is synchronized to the clock. The voltage injector generates a stepped wave whose amplitude changes in synchronization with a clock, applies a signal based thereon as the AC voltage. The current measuring unit converts the current in the detection coil to a voltage signal, carries out synchronous detection using the reference signal, and measures the AC current based on the synchronous detection result.

Abstract: A method of obtaining an electrical property of a test sample, comprising a non-conductive area and a conductive or semi-conductive test area, by performing multiple measurements using a multi-point probe. The method comprising the steps of providing a magnetic field having field lines passing perpendicularly through the test area, bringing the probe into a first position on the test area, the conductive tips of the probe being in contact with the test area, determining a position for each tip relative to the boundary between the non-conductive area and the test area, determining distances between each tip, selecting one tip to be a current source positioned between conductive tips being used for determining a voltage in the test sample, performing a first measurement, moving the probe and performing a second measurement, calculating on the basis of the first and second measurement the electrical property of the test area.

Abstract: A flyback converter includes a transformer to convert an input voltage into an output voltage, a control circuit senses a primary current of the transformer to generate a current sense signal, and a sensing circuit is configured to sense a variation of the current sense signal between two time points for extracting the input voltage information therefrom.

Abstract: An apparatus and method of testing electrical impedance of a multiplicity of regions of a photovoltaic surface includes providing a multi-tipped impedance sensor with a multiplicity of spaced apart impedance probes separated by an insulating material, wherein each impedance probe includes a first end adapted for contact with a photovoltaic surface and a second end in operable communication with an impedance measuring device. The multi-tipped impedance sensor is used to contact the photovoltaic surface and electrical impedance of the photovoltaic material is measured between individual first ends of the probes to characterize the quality of the photovoltaic surface.

Abstract: A test device for measuring permeability of a barrier material. An exemplary device comprises a test card having a thin-film conductor-pattern formed thereon and an edge seal which seals the test card to the barrier material. Another exemplary embodiment is an electrical calcium test device comprising: a test card an impermeable spacer, an edge seal which seals the test card to the spacer and an edge seal which seals the spacer to the barrier material.

Abstract: A chip on glass substrate includes a substrate, first, second, and third pads that are arranged on the substrate and that are electrically connected to an IC device, and first to fourth conductive patterns. A first conductive pattern is arranged on the substrate, has one end electrically connected to the first pad, and has another end that is electrically floated. Second and third conductive patterns are arranged on the substrate, each have one end electrically connected to the second pad, and each have another end that is electrically floated. A fourth conductive pattern is arranged on the substrate, has one end electrically connected to the third pad, and has another end that is electrically floated.

Abstract: High-frequency resonance method is used to measure magnetic parameters of magnetic thin film stacks that show magnetoresistance including MTJs and giant magnetoresistance spin valves. The thin film sample can be unpatterned. Probe tips are electrically connected to the surface of the film (or alternatively one probe tip can be punched into the thin film stack) and voltage measurements are taken while injecting high frequency oscillating current between them to cause a change in electrical resistance when one of the layers in the magnetic film stack changes direction. A measured resonance curve can be determined from voltages at different current frequencies. The damping, related to the width of the resonance curve peak, is determined through curve fitting. In embodiments of the invention a variable magnetic field is also applied to vary the resonance frequency and extract the magnetic anisotropy and/or magnetic saturation of the magnetic layers.

Abstract: A signal acquisition system has a signal acquisition probe having probe tip circuitry coupled to a resistive center conductor signal cable. The resistive center conductor signal cable of the signal acquisition probe is coupled to a compensation system in a signal processing instrument via an input node and input circuitry in the signal processing instrument. The signal acquisition probe and the signal processing instrument have mismatched time constants at the input node with the compensation system having an input amplifier with feedback loop circuitry and a shunt pole-zero pair coupled to the input circuitry providing pole-zero pairs for maintaining flatness over the signal acquisition system frequency bandwidth.

Abstract: A cellular communication device has one or more access modes which allow reading and writing of data, for example to change its settings, for example passwords and even the entire operating system and also permitting access to personal information such as the user's telephone book. To prevent cloning and like illegal access activity, the device is configured by restricting access to such data access modes using a device unique security setting. The setting may be a password, preferably a one-time password, or it may be a unique or dynamic or one time configuration of the codes for the read and write instructions of the data mode. There is also disclosed a server, which manages the security settings such that data mode operates during an active connection between the device and the server, and a secure communication protocol for communicating between the server and the cellular device.

Abstract: A test probe has a probe portion, a current source lead attachment portion and a voltage sense lead attachment portion. The test probe includes two conductive halves secured together with an electrically insulating material disposed between the halves electrically insulating them from each other. Each half has an “L” shape including a probe portion and a test lead attachment portion extending perpendicularly outwardly from the probe portion, and provides the test probe with an overall “T” shape. The conductive halves can be made of copper-beryllium. Methods of providing and using the test probe can include uncoupling a male coupling member of a power cable connector of a loadbreak bushing assembly from a female coupling member of the loadbreak bushing and inserting the rod-shaped probe portion into the female coupling member.

Abstract: A high voltage detection device comprises a probe comprising an electrode for contacting a high voltage electrical line. The electrode is connected in series with a resistor. A meter comprises a housing enclosing an electrical circuit for measuring line voltage. The electrical circuit comprises an input circuit for connection to the probe. The input circuit is adapted to suppress high frequency noise pick up by the probe and develop a bipolar voltage representing measured line voltage. A voltage detection circuit comprises a differential amplifier circuit for converting the bipolar voltage to a proportionate voltage signal. A signal processing circuit receives the proportionate voltage signal and drives the display for displaying the measured line voltage.

Abstract: An aspect of the invention provides a method for measuring I-V characteristics of a solar cell, the solar cell comprising a plurality of fine line-shaped electrodes formed on a first surface in a predetermined direction; and a coupling line formed on the first surface that electrically couples at least two fine line-shaped electrodes among the plurality of fine line-shaped electrodes, the coupling line having a line width larger than a line width of the fine line-shaped electrodes. The method includes: contacting a probe pin for voltage measurement with the coupling line; contacting two or more probe pins for current measurement electrically connected to each other with two or more fine line-shaped electrodes including the fine line-shaped electrodes coupled to each other by the coupling line among the plurality of fine line-shaped electrodes; and measuring I-V characteristics while irradiating the first surface with light.

Abstract: Disclosed herein are devices, systems, and methods for measuring an electropharyngeogram (EPG) in living organisms. In some embodiments, the devices and systems disclosed herein include an array for sorting and immobilizing an organism (such as a nematode) for measurement of an EPG and/or optical imaging. Also disclosed are methods for identifying therapeutic or toxic compounds utilizing the disclosed devices and systems. In some embodiments, the methods include screening for compounds with anthelmintic activity, toxicity (for example HERG channel blockers), or candidate drugs for treatment of a variety of human and/or animal diseases.

Abstract: A signal acquisition system has a signal acquisition probe having probe tip circuitry coupled to a resistive center conductor signal cable. The resistive center conductor signal cable of the signal acquisition probe is coupled to a compensation system in a signal processing instrument via an input node and input circuitry in the signal processing instrument. The signal acquisition probe and the signal processing instrument have mismatched time constants at the input node with the compensation system providing pole-zero pairs for maintaining flatness over the signal acquisition system frequency bandwidth.

Abstract: The resistance measuring device of the present invention includes switch transistors and switch conductive lines disposed between the bonding pads on a first substrate and between the bumps on a second substrate, such that the bonding pads and the bumps are conducted when the transistors are turned on, and the bonding resistance between at least one of the bonding pads and its corresponding bump can be directly measured.

Abstract: An apparatus and method for measuring and monitoring layer properties in web-based processes are described. The apparatus includes multiple electrode devices adjacently positioned on a surface of a web material, which advances with a predetermined speed. The electrode devices perform measurements of electrical parameters of a layer of the web material and provide an electrical signal to a layer deposition system for further adjustment of layer properties of the layer.

Abstract: A fall of potential method of determining earth ground resistance which utilizes an earth ground tester and eliminates the need for utilizing removable ground stakes. Rather than utilizing a “far stake” the method provides connection of the earth ground tester to the telephone wires. Rather than utilizing a “near stake” the method provides for connection of the earth ground tester to the cable shield.

Abstract: A four-wire ohmmeter connector includes a pair of elongated members spaced apart from each other by an interconnecting web. A pair of elongated contacts are mounted on forwardly projecting portions of each of the elongated members. An insulative housing surrounds the elongated members, contacts and web. The contacts mounted on one of the elongated members are connected through separate wires to a positive probe, and the contacts mounted on the other of the elongated members are connected through separate wires to a negative probe. The elongated members are inserted into respective terminal apertures of a four-wire ohmmeter. A pair of semi-cylindrical conductive sleeves are aligned with each of the apertures, and they make contact with and compress the respective contacts that are inserted into the aperture.

Abstract: An exemplary four-wire milliohmmeter includes a main body and two probe assemblies electrically connected with the main body. Each of the probe assemblies includes two plugs detachably inserted into the main body, a contact member, and two wires each electrically connecting one of the plugs to the contact member. The contact portion of each probe assembly has a needlelike free end for contacting an object.

Abstract: Various exemplary embodiments provide probes, systems and methods for measuring an effective electrical resistance/resistivity with high sensitivity. In one embodiment, the measuring system can include an upper probe set and a similar lower probe set having a sample device sandwiched there-between. The device-under-test (DUT) samples can be sandwiched between two conductors of the sample device. Each probe set can have an inner voltage sense probe coaxially configured inside an electrically-isolated outer current source probe that has a large contact area with the sample device. The measuring system can also include a computer readable medium for storing circuit simulations including such as FEM simulations for extracting a bulk through-plane electrical resistivity and an interface resistivity for an effective electrical z-resistivity of the DUT, in some cases, having sub-micro-ohm resistance.

Abstract: A conductivity measuring apparatus includes a probe base having a pair of electrodes disposed on respective opposite surfaces of a portion of the probe base. Observing and grasping probes are supported by the probe base in a cantilever state and are arranged adjancent to and spaced apart from one another by a predetermined distance. The grasping probe has a pair of electrodes disposed on respective opposite surfaces of a portion of the grasping probe confronting the portion of the probe base. A voltage apparatus applies a voltage between the pairs of electrodes on the probe base and the grasping probe to adjust the predetermined distance between the grasping and observing probes. A movement mechanism moves a sample base and the observing and grasping probes relative to each other to bring conductive tips of the observing and grasping probes into contact with respective contact points on a sample supported on the sample base.

Abstract: Techniques for estimating resistance and capacitance of metal interconnects are described. An apparatus may include an interconnect, a set of pads, a set of isolation circuits, and a test circuit. The set of pads may be coupled to the interconnect and used for simultaneously applying a current through the interconnect and measuring a voltage across the interconnect. The current and voltage may be used to estimate the resistance of the interconnect. The test circuit may charge and discharge the interconnect to estimate the capacitance of the interconnect. The isolation circuits may isolate the pads from the interconnect when the test circuit charges and discharges the interconnect. The apparatus may further include another interconnect, another set of pads, and another set of isolation circuits that may be coupled in a mirror manner. Resistance and/or capacitance mismatch between the two interconnects may be accurately estimated.

Abstract: The invention concerns a probe with at least two test prods, which are provided on a changing device connected to the probe and which can be alternately connected to an electric waveguide running inside the probe.

Abstract: Calculating resistance correction factors includes contacting the arms of a four-arm probe with a test sample; selecting a first set of first and second arms and a second set of third and fourth arms; applying a first current from the first arm to the second arm of the first set; detecting a first voltage between the third and fourth arms of the second set; calculating a first resistance using the first voltage and current; selecting a third set of first and second arms including no more than one arm of the first set, and a fourth set of third and fourth arms including no more than one arm of the second set; applying a second current from the first arm to the second arm of the third set; detecting a second voltage between the third and fourth arms of the fourth set; calculating a second resistance using the second voltage and current; and calculating a correction factor using the first and second resistances.