A circuit for an inductive conductivity sensor comprises: a secondary coil having a first coil terminal and a second coil terminal, a switch having a first switch terminal, a second switch terminal, a third switch terminal, a first potential terminal, and a control unit having a first control terminal and a second control terminal, wherein the first coil terminal is connected to the first control terminal and the second coil terminal is connected to the first switch terminal, wherein the second switch terminal is connected to the first potential terminal and the third switch terminal is connected to the second control terminal.

According to aspects of the present disclosure, systems and methods for measuring fluid resistivity are described herein. An example system may include a non-conductive tube. The non-conductive tube may be filled with a fluid, such as a formation fluid or drilling fluid, whose resistivity needs to be determined. A transmitter may be disposed around an outer surface of the non-conductive tube. A first receiver may be disposed around the outer surface of the non-conductive tube, and a second receiver may be positioned within a bore of the non-conductive tube. The transmitter may generate a primary electromagnetic field in a fluid within the tube, which may in turn generate an eddy current and a secondary electromagnetic field. The first and second receivers may be used to identify the eddy current and the resistivity of the fluid.

An electronic device including a continuity sensor and electrical circuitry configured to detect and report the continuity state of an article, container or product packaging is disclosed. The continuity sensor includes a first substrate with first and second coils thereon, and a second substrate with a third coil thereon. The first coil has an integrated circuit electrically connected thereto. The first substrate is part of, or is attached or secured to a part of the article, container or packaging. The second substrate is another part of, or is attached or secured to another part of the article, container or packaging. One of the article, container or packaging parts is (re)movable with respect to the other part. The first and second coils have one coupling when the article, container or packaging is closed or sealed, and a different coupling when the article, container or packaging is open or unsealed.

Differences of electromagnetic (EM) properties between healthy and cancerous tissues allow detection of abnormal conditions occurring in a tissue of an animal, for example, intra-operative cancer detection. By using a time-varying EM field, electrical eddy currents are generated in the tissue sample, and assessed using phase-sensitive detection. In some aspects, a change in phase shift between the voltage in a receiver coil and the voltage in a driver coil provide a direct and immediate indication of differences in EM properties of specimens.

The present invention aims to provide a coil unit for improving an accuracy in detecting foreign matter and an apparatus for detecting foreign matter which improves the accuracy in detecting foreign matter when a power is transmitted in a contactless manner. A power feeding coil unit (a coil unit) of the present invention is provided with a power feeding coil (a coil for power transmission) and an apparatus for detecting foreign matter. The apparatus for detecting foreign matter is provided with a plurality of resonators having a resonator coil and a resonator capacitor and also an excitation coil for exciting the plurality of resonators. The plurality of resonators are disposed to cover at least an area interlinking with a magnetic flux generated by the power feeding coil and to decrease an influence of mutual inductance.

An oil state detection apparatus detects the amount of degradation substances contained in oil. The oil state detection apparatus includes a first oscillation circuit including a coil 1 and a capacitor 2, and a first detection device. Either one of the coil 1 or the capacitor 2 is configured to be immersed in oil. The first detection device is configured to detect the oscillatory frequency of the oscillation circuit.

A measurement method for early detection of damage to a blade of an impeller of a turbine is provided. During operation, in a rotational direction of the blade along a circumference which surrounds the impeller, at a plurality of points, in each case a plurality of magnetic fields are generated next to one another substantially in an oscillation direction of the blade, which magnetic fields are influenced by a tip of a turbine blade during transit. Positional values of the tip are detected by at the plurality of points. A positional profile of the turbine blade is then formed from the positional values and a frequency is determined from the positional profile. The frequency is compared with defined frequency values. An alarm event is recognized in case of a sudden and/or pronounced change in the frequency. In addition, a turbine is provided which is configured to carry out the method.

The device for the impedance-based probing of materials described herein comprises a two-dimensional array of coils (1) and a measurement unit (4) adapted to determine, for each coil (1), a parameter indicative of its impedance. A pulse generator (3) is able to generate current pulses in each coil (1). The circuitry drives and senses the coil array through row and column lines (rp1 . . . rpN1, cp1 . . . cpN2, c21 . . . csN2) in order to minimize the number of required components. The device can, in particular, be used for probing concrete.

A measurement system may include control electronics; an electrical signal source; a plurality of measurement system electrical contacts; at least one feature for repeatably electrically connecting the plurality of measurement system electrical contacts to selected locations of a tested material. The control electronics may be configured to cause the electrical signal source to output an electrical signal; determine a measured voltage in response to the electrical signal using a measurement electrical contact from the plurality of measurement system electrical contacts. The measurement electrical contact is electrically coupled to the tested material. The control electronics also may be configured to determine whether the tested material includes a crack or other defect based on the measured voltage.

An electro-magnetic induction fluid conductivity sensor is described which includes a hollow non-conductive body defining a fluid chamber. The fluid chamber has a first end and a second end. A voltage transformer is provided which is capable of inducing an electric field into fluid positioned within the fluid chamber, thereby causing an electric current to flow through the fluid. An instrument is provide for measuring the electric current. A conductive shunt receives the electric current induced by the voltage transformer in the liquid at the first end of the sample chamber and returning the electric current to the second end to complete an electrical circuit.