791results about "Magnetic field measurement using flux-gate principle" patented technology

A magnetic field sensor for measuring at least two components of a magnetic field comprises a ferromagnetic core mounted on a semiconductor chip, an exciter coil to which a current can be applied and two read-out sensors. The ferromagnetic core is ring-shaped. The exciter coil is preferably formed from conductor tracks of the semiconductor chip and from bonding wires.

An apparatus having a plurality of coils (e.g., numerous thin-film coils formed in an array on a flex circuit), each coil acting as an excitation unit that generates an alternating excitation magnetic signal; and as a sensor configured to detect an eddy-current signal's phase and amplitude changes relative to the excitation magnetic signal. In some embodiments, the apparatus electronically scans a surface (e.g., of a metal plate) by successively switching to individual ones of the plurality of excitation / sensing coils (using, e.g., an analog multiplexer) without physical movement in order to detect anomalous signal changes in a manner that reduces signal changes due to probe lift-off relative to the surface. In some embodiments, the coils are placed across a large area of interest, for inspection of a large surface area in a few seconds without moving the apparatus. This can provide high-sensitivity detection and an accurate indication of flaw locations.

A roll-detecting sensor assembly includes a coil extending along and disposed about an axis. The coil comprises one or more portions, with each portion defining a winding angle. At least one of the portions defines a winding angle that is substantially nonzero relative to a line perpendicular to the axis, whereby the projected area of the coil in an applied magnetic field changes as the coil rotates about the axis. As a result, the coil is configured to produce a signal responsive to the magnetic field indicative of the roll of the sensor about the axis. In an embodiment, at least one of the portions defines a winding angle that is at least 2 degrees. In an embodiment, at least one of the portions defines a winding angle that is about 45 degrees.

A magnetic field sensor for the measurement of at least one component of a magnetic field comprises a ferromagnetic core that serves as a magnetic field concentrator, an excitation coil and a read-out sensor. The read-out sensor preferably comprises two sensors arranged in the vicinity of the outer edge of the ferromagnetic core and measures the at least one component of the magnetic field. The ferromagnetic core is ring-shaped or disc-shaped. On operation of the magnetic field sensor, a current is temporarily applied to the excitation coil in order to bring the ferromagnetic core into a state of predetermined magnetization in which the magnetization of the ferromagnetic core produces no signal in the read-out sensor.

A gradiometer for measuring properties of a magnetic field and in particular, for measuring magnetic field gradient components, comprising at least two magnetic sensors wherein at least two of the magnetic sensors are arranged to sense the magnetic field component in substantially the same direction. The magnetic sensors may be super conducting quantum interference device (SQUID) magnetometers, Hall probes, flux gates or magneto-resistive magnetometers. The gradiometer also includes a computer processor loaded with an adaptive signal-processing algorithm, for performing adaptive signal balancing of the magnetometer outputs. In a preferred embodiment the gradiometer may comprise at least eight magnetometers in a three-dimensional arrangement, and a set of three orthogonal global feedback coils, one for each direction x, y, z, such that the five independent magnetic field gradient components may be measured. The gradiometer may also be used to measure second or higher order magnetic field gradient components.

An input device using a geomagnetic sensor includes a geomagnetic sensor outputting a voltage corresponding to geomagnetism, and a control part calculating an azimuth using the voltage output from the geomagnetic sensor and calculating the rotation angle by comparing the azimuth to a previously measured azimuth, thereby generating the input signal corresponding to the rotation angle when the input device is tilted within a certain range. Accordingly, unwanted generation of the input signal is prevented when the input device is tilted by more than a certain angle.

A system and method for tracking an object through a three dimensional space is provided that uses the generation and detection of various magnetic fields to provide three-dimensional location data. The integrity of the generated magnetic fields are monitored against a baseline in order to detect compromise by the unintentional introduction of a foreign metallic or magnetic object in the procedural space.

A magnetic field measurement system includes an array of magnetometers; at least one magnetic field generator with each of the at least one magnetic field generator configured to generate a first magnetic field at one or more of the magnetometers, wherein the generated first magnetic field combines with the ambient magnetic field to produce a directional magnetic field at the one or more of the magnetometers, where a magnitude and direction of the directional magnetic field is selectable using the at least one magnetic field generator; and a controller coupled to the magnetometers and the at least one magnetic field generator, the controller including a processor configured for receiving signals from the magnetometers, observing or measuring a magnetic field from the received signals, and controlling the at least one magnetic field generator to generate the first magnetic field and select the direction of the directional magnetic field.

An electrical signal processing device includes at least one thin film flux generator and at least one thin film magnetic sensor. Each flux generator includes at least one conductive induction line that is connected to at least one lead of a pair of input leads, and a yoke that surrounds the conductive induction line. The yoke has at least one pair of pole tips, and a gap is disposed between the end surfaces of each pair of pole tips. A magnetic sensor is disposed in the gap, and a pair of output leads is connected to the sensor. An alternative embodiment may include two or more conductive induction lines that are connected to respective separate pairs of input leads. Alternatively, two or more conductive induction lines may connect to one another to form an induction coil. The flux generator and magnetic sensor are preferably formed on a single substrate to create an integrated device.

A current sensor for outputting a detection signal corresponding to a current flowing through a bus bar. The current sensor includes a magnetic core that concentrates and amplifies magnetic flux generated by the current near a detection portion of the bus bar. A magnetic detection element detects the magnetic flux concentrated by the magnetic core and outputs an electrical signal corresponding to the detected magnetic flux. A signal processing circuit includes electronic components and processes the electrical signal output from the magnetic detection element to generate the detection signal. A lead frame holds the magnetic detection element and the electronic components. The magnetic detection element, electronic components, and lead frame are combined to form a single sensor module. The current sensor detects the current flowing through the bus bar with the sensor module and outputs the detection signal.

A magnetic-balance-system current sensor includes: a magnetoresistive element, a resistance value of the magnetoresistive element being changed by applying an induction magnetic field generated by a measurement target current; magnetic cores disposed near the magnetoresistive element; a feedback coil disposed near the magnetoresistive element and configured to generate a cancelling magnetic field that cancels out the induction magnetic field; and a magnetic-field detecting bridge circuit having two outputs. The measurement target current is measured on the basis of a current flowing through the feedback coil when the induction magnetic field and the induction magnetic field and the cancelling magnetic field cancel each other out. The feedback coil, the magnetic cores, and the magnetic-field detecting bridge circuit are formed on a same substrate. The feedback coil is of a spiral type, and the magnetic cores are provided above and below the feedback coil.

A magnetic sensing assembly for measuring magnetic field produced by a time varying electric current generated in geological formations is disclosed. The assembly comprises a soft magnetic core, a sensing coil wound on the core, and at least one miniature low noise magnetic field sensor disposed near an edge of the magnetic core. Due to strong magnetic flux concentration effect of the magnetic core the sensor facilitates very low noise magnetic measurements at a low rate of change of the magnetic field, while the sensing coil offers high sensitivity and low noise measurement at higher rates. The magnetic sensing assembly preferably comprises an earth field cancellation element. The assembly also includes an acquisition means synchronized with an electromagnetic transmitter to receive and process signals from sensing coil and from magnetic field sensor.

A magnetic sensor arrangement (1), having magnetically sensitive sensor elements (7, 8) whose electrical properties are changeable as a function of a magnetic field that a moving, passive transmitter element (11) is able to influence. The magnetic sensor arrangement (1) has two sensor elements (7, 8) in a gradiometer arrangement that are each respectively associated with one of two magnetic regions (4, 5) of a permanent magnet embodied in the form of a gap magnet (2; 20; 23), which regions are spaced apart from each other by a predetermined distance (sa). The regions (4, 5) and the gap magnet (2; 20; 23)—in terms of the for example wedge-shaped embodiment, the dimensions (h, b, t), the gap width (sa), the gap depth (st), and their positions in relation to the sensor elements (7, 8)—are situated so as to minimize the offset of the output signal of the sensor elements (7, 8) in the gradiometer arrangement.

The use of magnetic field sensing to perform sophisticated command control and data input into a portable device is disclosed. A magnetic field sensor is embedded or fixedly attached to a portable device to measure changes in the magnetic field strength and / or direction accompanying movement, motion or tilt of the device in one-, two- or three-dimensions when the portable device is used to air-write or make gestures.

A magnitude and direction of at least one of a reset current and a second stabilization current (that produces a reset field and a second stabilization field, respectively) is determined that, when applied to an array of magnetic sense elements, minimizes the total required stabilization field and reset field during the operation of the magnetic sensor and the measurement of the external field. Therefore, the low field sensor operates optimally (with the highest sensitivity and the lowest power consumption) around the fixed external field operating point. The fixed external field is created by other components in the sensor device housing (such as speaker magnets) which have a high but static field with respect to the low (earth's) magnetic field that describes orientation information.

Disclosed herein is a very low noise fundamental mode orthogonal fluxgate magnetometer. Also disclosed is a method of measuring a magnetic field, and an integrated magnetotelluric station that can measure X, Y, and Z components of a magnetic field.

A flexible current sensor including a sensing cable with a sensing coil wound on a cylindrical flexible core and electrical shielding located over said sensing coil and an outer isolation coat. The electrical shielding includes a plurality of individually isolated shielding wires arranged into groups wound in mutually opposite directions and / or the sensing coil includes a plurality of individually isolated sensing wires arranged into groups wound in mutually opposite directions.

The invention provides an electromagnetic system for detecting a distance between adjacent wells while drilling, which is capable of providing accurate guide measurement and calculation for the control of well tracks of wells with complex structures, such as a cross well, a U-shaped communicated well, a dual-horizontal well, an accident rescue well and the like. The electromagnetic system for detecting the distance between adjacent wells while drilling mainly comprises a magnetic pipe nipple, an electromagnetic measuring instrument and a method for calculating the distance between adjacent wells, wherein the magnetic pipe nipple is a hollow cylinder with API standard ports at the two ends consisting of a non-magnetic drill collar and a plurality of permanent magnets, and is used as a signal source for an electromagnetic guide system; the measuring instrument mainly comprises an underground searching tube and a ground system, and is mainly used for detecting a magnetic vector signal ofthe magnetic pipe nipple and for sending data to a computer through an RS-232 interface; and the computer processes and analyzes measured information by using the method for calculating the distance between adjacent wells so as to convert the measured information of a drill position into readable data for engineers. The electromagnetic system for detecting the distance between adjacent wells while drilling has a simple structure and convenient use, and provides an effective high and new technological measure for the detection and control of the distance between adjacent wells with complex structures.

A circuit for sensing a magnetic field has at least one saturable coil (L1). The circuit includes switches (S1, S2) controlled by a comparator (12) to drive the coil (L1) to saturation by alternating polarities of current. In the absence of an external magnetic field the currents are balanced. An applied external magnetic field causes an unbalance in the coil (L1) in reaching saturation. An unbalance current is applied through a sensing resistor (R2) to an integrator (20) to develop an output voltage (Vo) as a measure of the applied magnetic field. The switches (S1, S2) are implemented by transistor switches. Dual (FIG. 1) and single (FIG. 2) supply rail circuits are disclosed. The circuit finds particular application in torque transducers using magnetoelastic elements.

A printed circuit board integrated with a two-axis fluxgate sensor includes a first soft magnetic core formed lengthwise in a first axial direction, a first excitation coil formed of a metal film and wound around the first soft magnetic core, a first pick-up coil formed of a metal film and wound around the first soft magnetic core and the first excitation coil, a second soft magnetic core formed lengthwise in a second axial direction, the second axial direction being perpendicular to the first axial direction, a second excitation coil formed of a metal film and wound around the second soft magnetic core, a second pick-up coil formed of a metal film and wound around the second soft magnetic core and the second excitation coil, and a pad for establishing conductivity between the first and second excitation coils and the first and second pick-up coils and an external circuit.

The integrated magnetic sensor for detecting an external magnetic field, is formed by a body of semiconductor material having a surface; an insulating layer covering the body of semiconductor material; a magnetically sensitive region, for example a Hall cell, extending inside the body; and a concentrator of ferromagnetic material, extending on the Hall cell and having a planar portion extending parallel to the surface of the substrate on the insulating layer. The concentrator terminates with a tip protruding peripherally from, and transversely to, the planar portion toward the Hall cell. When the magnetically sensitive region is a sensing coil of a fluxgate sensor, it is formed on the substrate, embedded in the insulating layer, and the tip of the concentrator can reach as far as the sensing coil.

A magnetic sensor element of a flux gate type comprising a magnetism sensitive part (8a) formed by winding a coil (3) around a magnetic core layer (8), and magnetism collective part (8b) for guiding magnetic fluxes to the magnetism sensitive part (8a). Respective central parts of the magnetism collective part (8b) are connected with the respective ends of the magnetism sensitive part (8a). Therefor the magnetic core layer (8) is formed so as to resemble a letter H in planar shape. And the coil (3) of the magnetism collective part (8b) is a thin-film coil comprising a plurality of upper coil thin-films (12) and a plurality of lower coil thin-films (4) formed on an upper surface and a lower surface of the magnetic core layer (8) via insulation layers by connecting together the respective lower coil thin-films (4) and the upper coil thin-films (12), at respective adjacent ends thereof, so as to be sequentially continuous with each other.

A magnetic field sensor comprises a magnetic field sensing cell (10) and a magnetic shield (9) comprising at least two parts (12a, 12b) separated by an air-gap (20) and surrounding the magnetic field sensing cell positioned in a cavity (11) of the magnetic shield.

The invention discloses a bidirectional magnetic saturated time difference fluxgate sensor, which is characterized in that two ends of a sensor magnetic core are wound with exciting coils, the middle section of the sensor magnetic core is wound with induction coils, output poles of the induction coils are connected with an amplifying circuit, and the amplifying circuit is connected with a counting display circuit through a band-pass filter circuit and a retardation shaping circuit. By detecting and calculating a positive negative pulse time difference value output by the fluxgate sensor in a time domain, the strength of the measured magnetic field is judged. Compared with the prior fluxgate sensor, the detection circuit is simple, the measurement stability of the system is ensured without a feedback structure, a complex subsequent circuit is not needed, the required excitation current is lower, the data processing is simple, the measured relative quantity is little, the integral volume and power consumption of the sensor are effectively reduced, and the measurement result is acquired quickly. The fluxgate sensor avoids a filter-phase-sensitive demodulation-smooth filter circuit of the prior fluxgate sensor, makes up the defect that the prior fluxgate sensor has harsh process requirement, and achieves the digitized magnetic measurement of the fluxgate sensor.

The invention concerns a current transducer for measuring a current flowing through a cable, comprising at least one magnetic field sensor and an electronic circuit. The current transducer comprises a head with a ferromagnetic core optimized to reduce the effects of external magnetic fields. The invention further concerns a magnetic transducer comprising a magnetic field sensor and an electronic circuit. The electronic circuit comprises at least one current source, a transformer, a fully differential preamplifier coupled to the transformer, a phase sensitive detector coupled to the preamplifier and a logic block configured to operate the magnetic field sensor(s) to provide an AC output voltage. The magnetic field sensor(s) is preferably either a Hall element or an AMR sensor or a flux-gate sensor.