Abstract: A system for simulating the effects of use and aging on immersive coolants. Two conductive coils are immersed in a tank containing a sample of the coolant. The coils are spaced such that electrical activation of the first coil induces current in the second coil. A DC power source is provided to an inverter, which provides AC current for activating the first coil. The induced AC current in the second coil is delivered to a rectifier which converts the induced AC current to DC current. The DC current is then returned to the power source. The electromagnetic field between the coils simulates motor operation, so that the coolant's physical and chemical characteristics can be tested for the effects of use and aging.

Abstract: A pole unit including a vacuum interrupter switch having a fixed contact extending into one end of a vacuum chamber and being electrically coupled to a first terminal, and a moving contact extending into an opposite end of the chamber. A sliding contact is rigidly coupled to the moving contact and slidably coupled to a second terminal. The pole unit also includes an electromagnetic actuator including a coil, a rod coupled to the sliding contact and a spring positioned against the rod. The pole unit further includes a transmitter coil and a receiver coil that are electromagnetically coupled, where the receiver coil is electrically coupled to the actuator and is electrically isolated from the transmitter coil. In this configuration, the interrupter switch, the actuator and the receiver coil are at a line potential and the transmitter coil is at ground potential.

Abstract: A conductivity sensor for measuring the electrical conductivity of a liquid medium having at least a first coil, a current source and a control and evaluation unit, the current source being connected to the first coil. The conductivity sensor has the ability to determine a particularly large range of electric conductivity by at least a first electrode and a second electrode and at least one voltage measuring unit being provided, the voltage measuring unit being connected to the first electrode and the second electrode, the control and evaluation unit being connected to the current source and to the voltage measuring unit, and the first electrode and the second electrode being out of electrical contact with the first coil.

Abstract: A method and apparatus for controlling a set of sensor platforms. The apparatus comprises a map manager and a controller. The manager creates a visibility map for an area of interest for a set of sensor platforms. The map manager further updates the visibility map over time while the set of sensor platforms monitors the area of interest. The controller controls a route of each of the set of sensor platforms using the visibility map.

Abstract: Provided is a compact and lightweight electric field probe which has a transmitting/receiving function whereby piezoelectric crystals can be excited through the application of an alternating current electric field thereto, and piezoelectric effect signals can be detected with sufficient sensitivity. Also provided are a control system for the same, and a piezoelectric crystal detector. The electric near-field probe is provided with a capacitor, in which the space between two metal plates that are positioned parallel to each other is filled by a conductor or air, and a series resonance circuit, which has a prescribed resonance frequency and is connected in series to an inverter that is formed by winding a conductive wire around a toroidal core.

Abstract: Properties of a multiphase mixture flow are measured in a blind-tee. The measured properties include the permittivity and/or the conductivity of the multiphase mixture flowing through a conduit. The permittivity and/or conductivity are measured at liquid-rich region(s) in a blind-tee section of the conduit and are used to determine properties of a liquid phase of the multiphase fluid flow, including one of the water conductivity, water in liquid ratio and water volume fraction. One or more electromagnetic sensors may be used in the blind-tee to measure the permittivity and/or conductivity. The sensors may be in contact with the multiphase flow or be disposed behind a dielectric window.

Abstract: Provided is a pen type of apparatus for measuring multiple water qualities, which is capable of measuring acidity (pH) and electric conductivity (EC) without interfering with each other in agricultural water for hydroponic cultivation to easily confirm the measured results.

Abstract: An MRI-free non-destructive on-line system for detecting a presence of a material in a sample. The system includes: a flow conduit encompassed by a tunable RF coil and having an input duct and an output duct; a flow of the sample through the flow conduit; a signal detector that detects frequency-dependent output signals as a function of a frequency variation of the RF tunable coil within a frequency range of an RF resonant frequency of a standard sample of the substance; and a processing unit.

Abstract: An apparatus for measuring electrical conductivity of liquid is disclosed. The present invention as disclosed accurately and consistently measures infinitesimal conductivity of liquid by applying a stable reference signal to a conductivity sensor controlled with a constant temperature, and by low-noise processing on an output signal from the conductivity sensor. More specifically, infinitesimal conductivity of liquid can be repeatedly and accurately measured and change in performance of the detection apparatus over time can be minimized, by minimizing temperature variations, unstability of a reference signal, and noise effects to ensure stablility of a baseline as a measurement reference of the conductivity and accuracy of conductivity measurements.

Abstract: A storage vessel for a liquid has an arrangement for measuring the electric conductivity of the liquid situated in the vessel. The arrangement has a first contact and a second contact, which are wetted by the liquid and between which the conductivity is measured. The storage vessel has a first conductor loop with a first open end coupled electrically to the first contact and a second open end coupled electrically to the second contact.

Abstract: A peristaltic pump (2) for use in a sterilization apparatus (10) comprises: a flexible pump hose (44) having an outlet end and an inlet end, and an electrically conductive fitting (53) at each end; a motor-driven impeller (46) disposed in relation to the pump hose (44) such that when the impeller (46) is driven it will intermittently bear against the pump hose (44) so as to bring the internal walls of the pump hose together (62); a first electrode (52a) in contact with the conductive fitting (53a) at the outlet end of the pump hose (44), and a second electrode (52b) in contact with the conductive fitting (53b) at the inlet end of the pump hose (44); means (70) for applying a voltage across the first and second electrodes (52); and means (70) for measuring an electrical property between the conductive fittings (53). Other aspects of the invention provide a sterilization apparatus including the pump, and a method of using the sterilization apparatus.

Abstract: The present specification discloses a dialysis system having a reservoir module with a reservoir housing defining an internal space, a surface located within the internal space for supporting a container that contains dialysate, and a conductivity sensor located within the internal space, where the conductivity sensor has a coil, a capacitor in electrical communication with the coil, and an energy source in electrical communication with the circuit.

Abstract: A testing apparatus for measuring the material properties of solder balls includes a frame and a chuck base moveable in X, Y, Z dimensions, relative to the frame. A probe tip is fixed to the frame. A measuring device is mounted to the frame and maintains a spacing with relationship to the probe tip and which has an initial, known height above the chuck base.

Abstract: A conductivity sensor for measuring conductivity of a medium surrounding the conductivity sensor, including: a first toroidal coil, which surrounds a first traversing opening for accommodating the medium and which serves for inducing an electrical current in the medium, a second toroidal coil, which surrounds a second traversing opening for accommodating the medium and which serves for registering a magnetic field produced by the induced electrical current. At least one of the toroidal coils has a plurality of first conductor sections, which extend in a plane of a multi-ply circuit card, a plurality of second conductor sections, which extend in a second plane of the circuit card, and a plurality of first vias, which connect the first conductor sections with the second conductor sections.

Abstract: An inductively working sensor for determining the conductivity of a liquid medium.

Abstract: Exemplary embodiments of the present invention are directed to methods and devices for detecting open-circuit and short-circuit failure in an electromagnetic (inductive) measurement of the conductivity of liquids and on the sensor and cable wiring. An electromagnetic measurement of the conductivity of a liquid is performed by immersing a sensor into the liquid, wherein the sensor includes at least 2 toroidal cores, one of them carrying an excitation coil and the other carrying an induction coil. When an AC excitation voltage is applied to the excitation coil, an induced current or voltage can be measured in the induction coil which is proportional to the conductivity of the measured liquid.

Abstract: Systems and methods for estimating a physical characteristic of a seafood product are provided. In one system, the estimate is based on a slope defined by a ratio of changes in peak resonant amplitude and frequency of an electromagnetic resonant circuit in loaded and unloaded states. In another system, a first probe of a plurality of probes is driven with a test signal when the plurality of probes is loaded by a seafood product and the estimate is based on received test signals at one or more of the other probes. In another system, the estimate is based on the loading effect of a seafood product on an electromagnetic resonant circuit, which is also used to read an ID from an RFID associated with the seafood product. The systems and methods may be used for individual specimens, or to determine an average estimate for multiple specimens at one time.

Abstract: Exemplary embodiments of the invention include an input circuit for electromagnetic (inductive) measurements of the conductivity of liquids. The input circuit and the induction coil are directly coupled, and the arrangement includes a current-voltage converting circuit which accomplishes the transformation from current to voltage in the induction coil, and ensures the terminal voltage to be zero. Also there is an anti-saturation circuit which is composed of an integrating circuit and a voltage dividing circuit and serves to prevent saturation in the operational amplifier which is used for the current-voltage transformation. The circuit further includes features for the detection of an open-circuit failure of the sensor coil or cable.

Abstract: A conductivity sensor for measuring conductivity of a medium surrounding the conductivity sensor includes a first toroidal coil bounding a medium-receiving passageway and serving for inducing an electrical current in the medium, and a second toroidal coil also bounding the passageway and serving for registering a magnetic field produced by the electrical current. At least one of the toroidal coils has a plurality of first conductor segments, which extend in a plane of a multi-ply circuit board, a plurality of second conductor segments, which extend in a second plane of the circuit board, and a plurality of through-contacts, which connect the first conductor segments with the second conductor segments, wherein the first conductor segments, the second conductor segments and the through-contacts form, together, the windings of a toroidal coil.

Abstract: A sensor device and a method of making a sensor device. The sensor device includes a coil arrangement including a primary coil and a secondary coil. A conduit that is traversable by a flow in a figure-8 pattern is disposed as a yoke about the coil arrangement such that the coil arrangement is disposed in a vicinity of an intersection of the figure-8 pattern. The conduit includes at least two parts. A parting plane of the two parts is configured so as to enable the coil arrangement to be slip-fit mounted on the conduit before the two parts are joined together.

Abstract: A non metallic flow through electrodeless conductivity sensor is provided with a conduit having primary and secondary process fluid flowpaths to form a fluid loop. At least one drive and one sense toroid surround the conduit on the fluid loop. Voltage supplied to the drive toroid induces a current in the sense toroid via the fluid loop to eliminate any need for metallic electrodes in contact with the process fluid. At least one additional drive and/or sense toroid is disposed on the fluid loop to enhance induction. Optionally one or more sense coils are disposed about the conduit outside of the fluid loop to cancel out stray electrical noise. An optional conductor disposed along the conduit detects any fluid leakage through changes in resistance thereof.

Abstract: A non-invasive measurement system (110) for measuring the electrical potential of a voltage source (20, 120) includes a sensing electrode (50, 151) spaced from the voltage source (20, 120). Preferably the voltage source (20, 120) is within a biological cell (115) located in a nutrient bath (119) including electrolytic medium (117) and an object (30, 190) is a portion of the electrolytic fluid (117) located between the cell (115) and the sensing electrode (50, 151). A feedback electrode (181) is formed in an annular shape and surrounds the sensing electrode (50, 151) thus creating an annular fluid region therebetween. The value of the voltage in the annular region (131) is set substantially equal to the value of the voltage in the object (190) and therefore the impedance between the object (190) and a stray voltage source (40) is maximized.

Abstract: A measuring device is used to measure the state of oils of fats. Said measuring device comprises a housing, a hollow connecting element which is secured therein and a carrier which is applied to the opposite end of the connecting element, said carrier being used to receive a sensor which can be used to measure an electric property of the product which is to be measured. The sensor is in contact with an evaluation unit by means of at least one electric line which is arranged on a non-conductive carrier, which is arranged in the region of the housing and/or the end of the connecting element which is oriented towards the housing. The measuring device comprises a plurality of carriers which are arranged in a row and which are thermally insulated from each other.

Abstract: Transmit equalization over high speed digital communication paths may be compensated in a receiver for a probe on that path. In one example, a probe input provides a signal from an electronic communications path, the signal having been processed by a transmit equalizer. A filter circuit processes the signal to compensate for the transmit equalizer, and a decoder decodes the processed signal and produces an output for use by test equipment.

Abstract: A wideband differential signal probe includes separate paths to convert a lower frequency component and a higher frequency component of a differential signal to a lower frequency single ended signal and a higher frequency single ended signal which are combined for the probe's output which is commonly input to instrumentation.

Abstract: An apparatus (2) for measuring electrical conductivity in a material has a pair of electrically conducting elements (6), a first electrical conductor (9) coupled to the electrically conducting elements and coupling a first transformer core (10) and a second transformer core (12) to form a first current loop (8), and a second electrical conductor (17) of known resistance coupling the second transformer core (12) and a third transformer core (14) to form a second current loop (16).

Abstract: Sensor device for a household appliance that includes a body (2), detector device to measure at least one variable of a fluid and which includes a conductivity sensor, and a printed circuit (3) that receives the variables measured by the detector device. The body (2) includes a housing (20) where the printed circuit (3) is housed, and the device (1) also includes a cover (6) to close the housing (20). The body (2) also includes an inlet conduit (21) and an outlet conduit (22) through which said fluid passes, the housing (20), the printed circuit (3) and the cover (6) being disposed transversally to the conduits (21, 22) between the conduits (21, 22). The conductivity sensor is connected to said body (2) and is connected to or next to the printed circuit (3).

Abstract: A non metallic flow through electrodeless conductivity sensor is provided with a conduit having primary and secondary process fluid flowpaths to form a fluid loop. At least one drive and one sense toroid surround the conduit on the fluid loop. Voltage supplied to the drive toroid induces a current in the sense toroid via the fluid loop to eliminate any need for metallic electrodes in contact with the process fluid. At least one additional drive and/or sense toroid is disposed on the fluid loop to enhance induction. Optionally one or more sense coils are disposed about the conduit outside of the fluid loop to cancel out stray electrical noise. An optional conductor disposed along the conduit detects any fluid leakage through changes in resistance thereof.

Abstract: A non metallic flow through electrodeless conductivity sensor is provided with a conduit having primary and secondary process fluid flowpaths to form a fluid loop. At least one drive and one sense toroid surround the conduit on the fluid loop. Voltage supplied to the drive toroid induces a current in the sense toroid via the fluid loop to eliminate any need for metallic electrodes in contact with the process fluid. At least one additional drive and/or sense toroid is disposed on the fluid loop to enhance induction. Optionally one or more sense coils are disposed about the conduit outside of the fluid loop to cancel out stray electrical noise. An optional conductor disposed along the conduit detects any fluid leakage through changes in resistance thereof.

Abstract: Sensor device for a household appliance that comprises a body (2), detector means to measure at least one variable of a fluid and which comprise a conductivity sensor, and a printed circuit (3) that receives the variables measured by the detector means. The body (2) comprises a housing (20) where said printed circuit (3) is housed, and the device (1) also comprises a cover (6) to close said housing (20). Said body (2) also comprises an inlet conduit (21) and an outlet conduit (22) through which said fluid passes, said housing (20), said printed circuit (3) and said cover (6) being disposed transversally to said conduits (21,22) between said conduits (21,22). The conductivity sensor is connected to said body (2) and is connected to or next to said printed circuit (3).

Abstract: A non metallic flow through electrodeless conductivity sensor is provided with a conduit having primary and secondary process fluid flow paths to form a fluid loop. At least one drive and one sense toroid surround the conduit on the fluid loop. Voltage supplied to the drive toroid induces a current in the sense toroid via the fluid loop to eliminate any need for metallic electrodes in contact with the process fluid. At least one additional drive and/or sense toroid is disposed on the fluid loop to enhance induction. Optionally one or more sense coils are disposed about the conduit outside of the fluid loop to cancel out stray electrical noise. An optional conductor disposed along the conduit detects any fluid leakage through changes in resistance thereof. A temperature detector is supported within an electrically non-conductive holder extending into the fluid flow path, so that the detector is free from physical contact with the fluid.

Abstract: A sensor includes primary and secondary toroids disposed in spaced, coaxial relation to one another with a process flow path extending therethrough. Electrically conductive and non-metallic connectors are located at opposite ends of the flow path to physically contact the process fluid flowing therethrough. The primary toroid is configured to induce an electric current in the process fluid as the process fluid passes through the flow path, wherein the current varies with conductivity of the process fluid. The secondary toroid is configured to detect the electric current in the process fluid as the process fluid passes through the flow path, the current being proportional to the conductivity of the process fluid.

Abstract: A non-contact method of measuring the thickness of an insulator film on a semiconductor substrate includes: (i) charging the insulator film surface in a non-contact manner; (ii) obtaining a first flat band voltage by conducting, prior to the charging processing step, a C-V measurement on the semiconductor substrate; obtaining a second flat band voltage by conducting, after the charging processing step, a C-V measurement on the semiconductor substrate; and calculating, based on a difference between the first and second flat band voltages, the charge amount given to the insulator film surface by the charging processing step; (iii) then measuring the insulator film surface potential and (iv) calculating the insulator film thickness based on the charge amount measured at the charge amount measuring step and on the surface potential measured at the surface potential measuring step.

Abstract: A process for producing a thermoplastic resin composition is disclosed and comprises melt-kneading a resin composition containing from 40 to 90 parts by weight of (A) a polyamide resin, from 5 to 50 parts by weight of (B) a polyphenylene ether resin, from 5 to 30 parts by weight of (C) an aromatic vinyl compound-aliphatic hydrocarbon copolymer and from 0 to 30 parts by weight of (D) a polyolefin resin, per 100 parts by weight in total of the components (A), (B), (C) and (D), and further containing from 0.01 to 1.5 parts by weight of (E) an &agr;,&bgr;-unsaturated carboxylic acid or a derivative thereof per 100 parts by weight of the component (B), wherein the components (B), (C) and (E) are added from the upstream end of a melt-kneading machine and the component (A) is added part-way through the melt-kneading machine.

Abstract: The invention relates to an inductively operating sensor (1) for measuring the electrical conductivity of a fluid medium (2), having an excitation coil (3) to which an input signal is fed and a receiver coil (4) coupled to the excitation coil (3) via the fluid medium (2), the receiver coil (4) providing an output signal (IInd) which is a measurement of the conductivity of the fluid medium (2). The sensor (1) has means (5) for measuring a variable signal at the input of the excitation coil (3) for timely detection of damage to the windings of the excitation coil (3), the receiver coil (4), and/or to a power cable network for the sensor (1). The excitation coil (3) of the sensor is preferably fed by an input voltage (UErr) and the means (5) for measuring the variable signal preferably measure the input current (IErr) at the input of the excitation coil (3).

Abstract: A method and an apparatus for utilizing a periodic disconnection of a cathodic protection circuit, the voltage fluctuations caused on a cathodically protected structure by periodic disconnection of the protection circuit being detected in an apparatus and used for remote-controlled disconnection of a decoupling capacitor. Detection of periodically occurring negative-going voltage edges on a cathodically protected structure. The voltage supply of an apparatus through a capacitor or an electric circuit by means of a current transformer and a voltage outlet via a breaker.

Abstract: Methods and apparatuses for determining a fluid parameter in a vessel by altering a property of the fluid, sensing the difference in the property after the fluid is altered, particularly as related to the property in an unaltered portion of the fluid.

Abstract: The invention relates to a device and method for carrying out a contactless measurement of the conductivity of a liquid situated in a flow channel, and to the use of said device and method. According to the invention, the invention provides that a toroidal coil is precisely arranged around the flow channel. Said toroidal coil is interconnected with a capacitor to an oscillating circuit. The invention also provides that the electric characteristics of this circuit are then measured according to the conductivity which is sought after.

Abstract: Method and apparatus for quantitatively determining a degree of recirculalion flow in a vessel of a fluid by altering the electrical conductivity of the fluid, sensing the difference in electromagnetic field after the fluid is altered, and integrating the sensed difference over a period of time including any time of potential recirculation of any altered conductivity fluid.

Abstract: In a solids profile measurement system for determining the quality of a solids bed formed from a liquid-solid slurry in a vessel, a sensor adapted to generate signals indicative of a profile as measured by progressively immersing the sensor deeper into the slurry is provided. An extension mechanism, at least a portion of which is coupled at one end to the sensor and at an opposite end to a piece of processing equipment, is provided to affect retrograde movement in a first direction to immerse the sensor in a slurry, and in a second direction opposite the first direction. A controller in communication with the extension mechanism is also provided and issues commands thereto and receives signals generated by the sensor.

Abstract: A flow rate of a fluid flowing in a tube is quantitatively determined by altering the electrical conductivity of the fluid by injection of a bolus of saline. The electrical conductivity of the altered conductivity is measured over the time it takes the altered conductivity fluid to pass a conductivity measuring location. The measured conductivity is integrated over the time it takes to pass the conductivity measuring location. The integral is interpreted to determine the flow rate.

Abstract: A method of observing a physical and chemical property of a tissue or cell by using an apparatus which comprises at least a cell culturing means, an environment conditioning means, an observing means and a comparing means, comprising the steps of (A) culturing the tissue or cell by the cell culturing means, (B) maintaining a first physical and chemical environment around the tissue or cell by the cell culturing means, (C) observing a first physical and chemical property of the tissue or cell in the first physical and chemical environment by the observing means, (D) changing the first physical and chemical environment to a second physical and chemical environment by the environment conditioning means, (E) observing a second physical and chemical property of the tissue or cell in the second physical and chemical environment by the observing means, and (F) comparing the first physical and chemical property of the tissue or cell with the second physical and chemical property of the tissue or cell by the comparing

Abstract: A flow rate of a fluid flowing in a tube is quantitatively determined by altering the electrical conductivity of the fluid by injection of a bolus of saline. The electrical conductivity of the altered conductivity is measured over the time it takes the altered conductivity fluid to pass a conductivity measuring location. The measured conductivity is integrated over the time it take to pass the conductivity measuring location. The integral is interpreted to determine the flow rate.

Abstract: Molding compositions including polyhydroxyalkanoates are provided. The use of polyhydroxyalkanoates as a binder in molding compositions provides improved binder removal in the finished molded product, and offers a wide range of physical properties suitable for use in a variety of processing conditions. The composition preferably includes a powdered material, such as a metal powder, ceramic powder, or blend, admixed with a polyhydroxyalkanoate binder. The compositions are useful in powder processing techniques, such as injection molding, slip casting, tape casting, or extrusion.

Abstract: The fluid conductivity sensor disclosed herein is adapted for the non-contacting measurement of fluid conductivity and utilizes first and second insulating tubes, each of which is provided with both the driving transformer and the sensing transformer. The sensor is immersed in the fluid to be tested so that the tubes fill with the fluid. The driving transformer's are oppositely poled so that the current induced in one tube tends to return through the other tube. Shrouds are provided which link the corresponding ends of the tubes and operate to obstruct in-fluid current flow not linking both of the tubes. Accordingly the influence of objects nearby in the fluid is substantially eliminated.

Abstract: A highly accurate electromagnetic-induction-type conductivity and dielectric constant meter is obtained by using a calibration box (instrument) and a structure as below. The conductivity and dielectric constant meter employs an electromagnetic inductive probe which includes a primary transformer composed of a toroidal core with a wound primary coil, a secondary transformer composed of a toroidal core with a wound secondary coil, an electrostatic shield shielding the transformers, and cables that connect the probe to a meter. To eliminate the electrostatic capacity produced by causes other than electromagnetic induction, the structure of the probe is symmetrical. In a first embodiment, the secondary transformer is placed between two parts of the primary transformer, which has two cores of the same shape that are placed symmetrically.

Abstract: In an electric conductivity measurement circuit according to the invention, there are provided first and second cores for forming a closed flux loop in a liquid whose electric conductivity is to be measured, a first coil is wound on the first core, and a second coil is wound on the second core in a direction opposite to the direction of the winding of the first coil, a closed circuit includes the first and second coils, a reference resistor Rr and switch means, and the switch means is periodically turned on and off to periodically incorporate the reference resistor Rr in the closed circuit, thereby calculating the electric conductivity of the liquid by comparing a voltage induced at the second coil where the reference resistor Rr is incorporated in the closed circuit, with a voltage induced at the second coil where the reference resistor Rr is not incorporated in the closed circuit.

Abstract: An electromagnetic induction-type probe, for measuring the electrical properties of a solution, exhibits both a reduced size and a wide band property. The probe includes a primary transformer, composed of a toroidal core with a primary coil winding, a secondary transformer composed of a toroidal core with a secondary, coil winding, an electrostatic shield and coaxial cables which connect the probe and the main frame of a measuring instrument. The structure of the probe is symmetrical in order to eliminate measurement errors due to the asymmetry of the electrical field produced in the solution. The symmetry of the electrical field in the solution is maintained up to the high-frequency region and a wide-band effectiveness is realized by connecting the center tap terminal of a balancer to the outer conductors of the coaxial cables and the other terminals of the balancer to both ends of the gap of the electrostatic shield.

Abstract: A method is used which reduces measurement errors, especially of permittivity, which result when electromagnetic induction-type probes measure electrical properties of solutions. Part of the electromagnetic induction current, which the electromagnetic induction-type probe tries to induce in the test solution, flows in the stray capacitance, which is formed by the dielectric in the probe. This partial current reduces the current that is linked to the current detector transformer, and affects the measured value of the electrostatic capacity component, i.e., the permittivity, of the test solution. This phenomenon is modeled and is expressed by a distributed constant circuit which is simplified to a T-shaped 2-terminal pair equivalent circuit. A correction equation that corrects the errors due to the aforementioned currents is obtained by means of this simplified equivalent circuit, and the measurement errors are reduced.

Abstract: A highly accurate electromagnetic-induction-type conductivity and dielectric constant meter is obtained by using a calibration box (instrument) and a structure as below. The conductivity and dielectric constant meter employs an electromagnetic inductive probe which includes a primary transformer composed of a toroidal core with a wound primary coil, a secondary transformer composed of a toroidal core with a wound secondary coil, an electrostatic shield shielding the transformers, and cables that connect the probe to a meter. To eliminate the electrostatic capacity produced by causes other than electromagnetic induction, the structure of the probe is symmetrical. In a first embodiment, the secondary transformer is placed between two parts of the primary transformer, which has two cores of the same shape that are placed symmetrically.