JP2007147514A - Current sensor, and core of current sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a current sensor and a core of the current sensor, capable of preventing the core from being magnetic-saturated by convergence of an external magnetic field such as the geomagnetism onto the core, and capable of executing easily and efficiently posterior fitting. <P>SOLUTION: This current sensor includes the core 11 arranged to surround a conductive member 14 with a flowing measured current I, and for magnetic-converging a magnetic field generated by making the measured current I flow through the conductive member 14, and a magnetoelectric conversion element 12 for outputting an electric signal in response to the magnetic field magnetic-converged in the core. The core has the first clearance 15 capable of passing the conductive member 14 to be arranged in a position surrounding the conductive member 14 from a direction substantially vertical to a longitudinal direction of the conductive member 14, a magnetic route thereof is branched into the first magnetic route and the second magnetic route, in one part of the core 11, and the magnetoelectric conversion element 12 is provided in either of the first magnetic route or the second magnetic route branched therein. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a current sensor that measures a current value of a current to be measured based on a magnetic field generated around a conductive member through which the current to be measured flows, and a core of the current sensor.

  In the current sensor 50 disclosed in Japanese Patent Laid-Open No. 10-73619 (Patent Document 1), as shown in FIG. 4, an annular core 51 in which a gap 53 is partially formed surrounds the conductive member 54. In the gap 53, the magnetoelectric conversion element 52 is disposed.

In the current sensor 50 configured as described above, when the current I to be measured flows through the conductive member 54, the magnetic field generated around the conductive member 54 is focused on the core 51, and the magnetoelectric conversion element 52 passes through the gap 53. An electrical signal corresponding to the change in the magnetic field is output. Then, the current value of the current I to be measured is measured based on this electric signal.
JP-A-10-73619

  By the way, in the current sensor 50 disclosed in Patent Document 1, in addition to the magnetic field generated around the conductive member 54, an external magnetic field generated from an electronic device or a magnetic body disposed in the vicinity of the geomagnetism or the current sensor 50 is generated. It may be focused on the core 51.

  When the magnetic field focused on the core 51 exceeds a certain value, the core 51 is magnetically saturated, and thus the core 51 cannot focus the magnetic field according to the current I to be measured. Then, the current sensor 50 has a problem that it is difficult to accurately measure the current value of the current I to be measured.

  Further, when the conductive member 54 is arranged in advance in a storage case, a case, or the like, there is a problem that the work of retrofitting the core 51 so as to surround the conductive member 54 is not good in terms of work efficiency. .

  Therefore, the present invention has been made in view of the problems as described above, and the purpose of the present invention is to prevent magnetic saturation of the core by providing the core with a plurality of magnetic paths, and to facilitate the retrofit arrangement. It is another object of the present invention to provide a current sensor that can perform efficiently and a core of the current sensor.

  In order to solve the above problems, the inventions described in claims 1 to 6 relate to a current sensor that measures a current value of a current to be measured based on a magnetic field generated around a conductive member through which the current to be measured flows. is there.

  The current sensor according to claim 1 is disposed so as to surround a conductive member through which a current to be measured flows, a core for collecting a magnetic field generated by the current to be measured flowing through the conductive member, and a magnetic field collected by the core The core can pass the conductive member so that the core can be disposed at a position surrounding the conductive member from a direction substantially perpendicular to the longitudinal direction of the conductive member. The magnetic path is branched into a first magnetic path and a second magnetic path in a part of the core, and the magnetoelectric conversion element includes the branched first and second magnetic paths. It is provided in either one of these.

  As a result, the magnetic field collected in the core can be branched into the first and second magnetic paths, so that magnetic saturation of the core can be prevented. Moreover, since the 1st clearance gap which can let a conductive member pass is formed in the core so that it can arrange | position so that a conductive member may be surrounded, the arrangement | positioning of a core retrofit can be performed easily.

  The current sensor according to claim 2 is characterized in that the first magnetic path is located closer to the conductive member than the second magnetic path, and the magnetoelectric conversion element is provided in the first magnetic path. . Thereby, most of the magnetic field generated around the conductive member passes through the first magnetic path. Therefore, the magnetoelectric conversion element provided in the first magnetic path can detect the change in the magnetic field with high accuracy.

  The current sensor according to claim 3 is characterized in that the second magnetic path is provided in substantially the same plane so as to cover the first magnetic path. As a result, most of the external magnetic field passes through the second magnetic path. Therefore, the magnetic saturation of the core due to the magnetic field generated by combining the magnetic field generated around the conductive member and the external magnetic field can be prevented.

  The current sensor according to claim 4 is characterized in that a part of the second magnetic path is a low magnetic permeability part having a lower magnetic permeability than that of the second magnetic path. Thus, by appropriately adjusting the magnetic permeability of the low magnetic permeability portion, the magnetic field collected in the core can be branched to the first and second magnetic paths at a desired ratio. Therefore, the magnetoelectric conversion element can more easily detect a change in the magnetic field while preventing magnetic saturation of the core.

  The current sensor according to claim 5 is characterized in that the low magnetic permeability portion is the second gap. Thereby, it is not necessary to prepare a magnetic material having a low magnetic permeability and to incorporate this magnetic material into the core. Therefore, the low magnetic permeability portion can be easily provided at low cost.

  The current sensor according to claim 6 is characterized in that the width of the first gap is larger than the width of the conductive member. Thereby, the retrofit arrangement | positioning of a core can be performed easily and efficiently.

  The invention described in claims 7 to 12 relates to a core of the current sensor. By using the core of the current sensor for the current sensor, the same effects as those of the first to sixth aspects of the invention described above can be obtained, and thus the description thereof is omitted.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or is equivalent, and the description is abbreviate | omitted.

(First embodiment)
A first embodiment of a current sensor embodying the present invention will be described with reference to FIG. 1 which is a schematic sectional view.

  As shown in FIG. 1, the current sensor 10 according to this embodiment includes a core 11 and a magnetoelectric conversion element 12, and the current I to be measured flowing through the conductive member 14 based on the magnetic field generated around the conductive member 14. Current value is measured. The current sensor 10 includes a core 11, a magnetoelectric conversion element 12, a conductive member 14, and the like that are housed and disposed in a housing or a housing case, but the housing and the housing case are not illustrated.

  The core 11 is configured by laminating one or a plurality of plate-like pieces obtained by shearing a magnetic material having a relatively high magnetic permeability such as permalloy or supermalloy. Therefore, the core 11 has a magnetic saturation amount corresponding to the number of laminated plate-like pieces. Further, the core 11 can partially change the magnetic permeability (magnetic resistance) by partially changing the thickness and thickness.

  Hereinafter, each part of the core 11 will be described with reference numerals 11a to 11g. As shown in FIG. 1, a part of the core 11 is branched into a first magnetic path consisting of 11a to 11d and a second magnetic path consisting of 11e to 11g.

  The first magnetic path is located closer to the conductive member 14 than the second magnetic path. The first magnetic path and the second magnetic path are provided on the same plane, and the second magnetic path is provided so as to cover the first magnetic path.

  The outer frame portion (11c to 11g) of the core 11 is annular and is substantially U-shaped, and has a substantially bilateral shape with the ii line as the target line. Projecting portions 11a and 11b from the two opposite sides (sides consisting of 11c-11e and side consisting of 11d-11f) of the three sides constituting the U-shape of the core 11 toward the inside of the core 11 are provided. Is formed. The tip portions of the projecting portions 11a and 11b do not contact each other, and a gap 13 through which the magnetic field collected by the core 11 passes is formed between the tip portions. A magnetoelectric conversion element 12 is disposed inside or in the vicinity of the gap 13.

  The magnetoelectric conversion element 12 is mounted on a substrate (not shown), and is electrically connected to an external device (not shown) via the substrate (not shown). The magnetoelectric conversion element 12 outputs an electric signal corresponding to the magnetic field passing through the gap 13 toward an external device (not shown). For example, a Hall element or a magnetoresistive element can be used as the magnetoelectric conversion element 12, but the magnetoelectric conversion element 12 is not limited to this as long as it is an element that can output an electric signal corresponding to a magnetic field passing through the gap 13.

  In the current sensor 10 according to the present embodiment, for example, when the current I to be measured flows from the front surface to the back surface of the conductive member 14, a clockwise magnetic field is generated around the conductive member 14 toward the paper surface.

  In general, a magnetic field has a property of passing through a nearby magnetic path, a closed magnetic path, and a magnetic path having a high magnetic permeability (low magnetic resistance). Accordingly, a part of the magnetic field generated around the conductive member 14 (magnetic field B1a) passes through the first magnetic path disposed on the side close to the conductive member 14.

  However, since the gap 13 is formed in the first magnetic path, the magnetic permeability of the second magnetic path is larger (the magnetic resistance is smaller) than that of the first magnetic path. Therefore, the other part (magnetic field B1b) passes through the second magnetic path.

  By the way, depending on the installation location and use environment of the current sensor 10, a magnetic field B <b> 2 (broken arrow) different from the magnetic field B <b> 1 may be collected in the core 11 and pass through the core 11. The magnetic field B2 is based on an external magnetic field generated from, for example, an electronic device or a magnetic body disposed in the vicinity of the geomagnetism or the current sensor 10.

  In the current sensor 10 according to the present embodiment, even if such an external magnetic field is collected on the core 11, the external magnetic field passes through the first and second magnetic paths based on the above-described properties of the magnetic field. . That is, a part of the external magnetic field (magnetic field B2a) passes through the second magnetic path, and the other part (magnetic field B2b) passes through the first magnetic path.

  Therefore, in the current sensor 10 according to the present embodiment, in a part of the core 11, the magnetic path is branched into the first magnetic path and the second magnetic path, so that the magnetic field generated around the conductive member 14. B1 and the external magnetic field pass through the first and second magnetic paths separately. Thereby, magnetic saturation of the core 11 can be prevented.

  The ratio at which the magnetic fields B1 and B2 are separated from the first and second magnetic paths is substantially determined by the permeability ratio (magnetoresistance ratio) of each magnetic path and the distance ratio from the conductive member 14. Therefore, if these ratios are obtained in advance, the current value of the measured current I can be measured based on the magnetic field B1a passing through the gap 13.

  As shown in FIG. 1, the first conductive member 14 can be passed through the core 11 so as to be disposed at a position surrounding the conductive member 14 from a direction substantially perpendicular to the longitudinal direction of the conductive member 14. The gap 15 is formed. The width of the first gap 15 (the width between 11c and 11d) W ′ is assumed to be wider than the width W of the conductive member 14.

  Therefore, even when the conductive member 14 through which the current I to be measured flows is disposed in advance in a housing or a storage case (not shown), the core 11 can be disposed at a position surrounding the conductive member 14. That is, when the core 11 is retrofitted, the current sensor 10 can be easily and efficiently retrofitted with the core 11.

(Second Embodiment)
A second embodiment of the current sensor embodying the present invention will be described with reference to FIG. 2 which is a schematic sectional view. As shown in FIG. 2, the current sensor 20 in the present embodiment includes a core 21 and a magnetoelectric conversion element 12, and a magnetic field that generates a current value of the current I to be measured flowing through the conductive member 14 around the conductive member 14. It measures based on. The current sensor 20 includes the core 21, the magnetoelectric conversion element 12, the conductive member 14, and the like housed in a housing or a housing case, but the housing and the housing case are not shown.

  Hereinafter, each part of the core 21 will be described with reference numerals 21a to 21g. As shown in FIG. 2, the core 21 is partially branched into a first magnetic path consisting of 21a to 21d and a second magnetic path consisting of 21e to 21g.

  The first magnetic path is located closer to the conductive member 14 than the second magnetic path. The first magnetic path and the second magnetic path are provided on the same plane, and the second magnetic path is provided so as to cover the first magnetic path.

  The outer frame portions (21c to 21g) of the core 21 are annular and are formed in a substantially U shape, and are symmetrical with respect to the roll line as a target line. Projecting portions 21a and 21b are directed toward the inside of the core 21 from two opposing sides (sides consisting of 21c-21e and side consisting of 21d-21f) among the three sides constituting the U-shape of the core 21. Is formed. The tip portions of the protrusions 21a and 21b do not contact each other, and a gap 13 is formed between the tip portions through which the magnetic field collected by the core 11 passes. A magnetoelectric conversion element 12 is disposed inside or near the gap 13.

  The magnetoelectric conversion element 12 is mounted on a substrate (not shown), and is electrically connected to an external device (not shown) via the substrate (not shown). The magnetoelectric conversion element 12 outputs an electric signal corresponding to the magnetic field passing through the gap 13 toward an external device (not shown). For example, a Hall element or a magnetoresistive element can be used as the magnetoelectric conversion element 12, but the magnetoelectric conversion element 12 is not limited to this as long as it is an element that can output an electric signal corresponding to a magnetic field passing through the gap 13.

  As shown in FIG. 2, the current sensor 20 according to the present embodiment includes a low magnetic permeability portion 26 having a lower magnetic permeability than that of the other part of the second magnetic path. Yes. The low magnetic permeability part 26 interposes a magnetic material or air layer (second gap) having a magnetic permeability lower than the magnetic permeability of the material constituting the second magnetic path in the middle of the second magnetic path. Form. The magnetic permeability can be adjusted by replacing the magnetic material constituting the low magnetic permeability portion 26 or changing its width. The position where the low magnetic permeability portion 26 is formed can be changed as appropriate as long as it is on the second magnetic path.

  In the current sensor 20 according to the present embodiment, for example, when the current I to be measured flows from the front surface to the back surface of the conductive member 14, a clockwise magnetic field is generated around the conductive member 14 toward the paper surface.

  As described above, the magnetic field has a property of passing through a nearby magnetic path, a closed magnetic path, and a magnetic path having a high magnetic permeability (low magnetic resistance). Therefore, the current sensor 20 in the present embodiment uses this property to form the low magnetic permeability portion 26 in the second magnetic path, thereby reducing the magnetic permeability of the second magnetic path. The magnetic field B2b passing through the magnetic path is decreased, and the magnetic field B1a passing through the first magnetic path is increased.

  Thereby, the magnetoelectric conversion element 12 can easily detect the change of the magnetic field B1b passing through the gap 13, and can output an electric signal corresponding to the change to an external device (not shown).

  By the way, depending on the installation location and use environment of the current sensor 20, a magnetic field B <b> 2 (broken arrow) different from the magnetic field B <b> 1 may be collected in the core 21 and pass through the core 21. This magnetic field B2 is based on an external magnetic field emitted from, for example, an electronic device or a magnetic body disposed in the vicinity of the geomagnetism or the current sensor 20. Since the magnetic field has the properties as described above, a part of the external magnetic field (magnetic field B2a) is focused on the second magnetic path and the other part (magnetic field B2b) passes through the first magnetic path. Will pass.

  However, in the current sensor 20 according to the present embodiment, even if such an external magnetic field is focused on the core 21, the external magnetic field passes through the first and second magnetic paths based on the above-described properties of the magnetic field. To do. That is, a part of the external magnetic field (magnetic field B2a) passes through the second magnetic path, and the other part (magnetic field B2b) passes through the first magnetic path.

  Therefore, in the current sensor 20 according to the present embodiment, the magnetic path generated in the periphery of the conductive member 14 is obtained by branching the magnetic path into the first magnetic path and the second magnetic path in a part of the core 21. B1 and the external magnetic field pass through the first and second magnetic paths separately. Thereby, magnetic saturation of the core 21 can be prevented.

  The ratio at which the magnetic fields B1 and B2 are separated from the first and second magnetic paths is substantially determined by the permeability ratio (magnetoresistance ratio) of each magnetic path and the distance ratio from the conductive member 14. Therefore, if these ratios are obtained in advance, the current value of the measured current I can be measured based on the magnetic field B1a passing through the gap 13.

  As shown in FIG. 2, the first conductive member 14 is allowed to pass through the core 21 so as to be disposed at a position surrounding the conductive member 14 from a direction substantially perpendicular to the longitudinal direction of the conductive member 14. The gap 15 is formed. The width of the first gap 15 (the width between 21c and 21d) W ′ is assumed to be wider than the width W of the conductive member 14.

  Therefore, even when the conductive member 14 through which the current I to be measured flows is disposed in advance in a housing or a storage case (not shown), the core 21 can be disposed at a position surrounding the conductive member 14. That is, when the core 21 is retrofitted, the current sensor 20 can be easily and efficiently retrofitted with the core 21.

(Third embodiment)
A third embodiment of the current sensor embodying the present invention will be described with reference to FIG. 3 which is a schematic sectional view. As shown in FIG. 3, the current sensor 30 in this embodiment includes a core 31 and a magnetoelectric conversion element 12, and generates a current value of the current I to be measured flowing through the conductive member 14 around the conductive member 14. The measurement is based on a magnetic field. The current sensor 30 includes the core 31, the magnetoelectric conversion element 12, the conductive member 14, and the like housed in a housing or a housing case. However, the housing and the housing case are not illustrated.

  Hereinafter, each part of the core 11 will be described with reference numerals 31a to 31g, 31m, and 31n. As shown in FIG. 3, the core 31 is partially branched into a first magnetic path composed of 31a to 31d, 31m, and 31n and a second magnetic path composed of 31e to 31g.

  The first magnetic path is located closer to the conductive member 14 than the second magnetic path. The first magnetic path and the second magnetic path are provided on the same plane, and the second magnetic path is provided so as to cover the first magnetic path.

  The outer frame portions (31c to 31g, 31m, 31n) of the core 31 are annular and are substantially U-shaped, and are bilaterally symmetric with respect to the ha line. Projecting portions 31a and 31b are directed to the inside of the core 31 from two opposing sides (sides formed of 31c-31e and side formed of 31d-31f) among the three sides constituting the U-shape of the core 31. Is formed. The tip portions of the protruding portions 31a and 31b are not in contact with each other, and a gap 13 through which a magnetic field collected by the core 11 can pass is formed between the tip portions. A magnetoelectric conversion element 12 is disposed inside or near the gap 13.

  The magnetoelectric conversion element 12 is mounted on a substrate (not shown), and is electrically connected to an external device (not shown) via the substrate (not shown). The magnetoelectric conversion element 12 outputs an electric signal corresponding to the magnetic field passing through the gap 13 toward an external device (not shown). For example, a Hall element or a magnetoresistive element can be used as the magnetoelectric conversion element 12, but the magnetoelectric conversion element 12 is not limited to this as long as it is an element that can output an electric signal corresponding to a magnetic field passing through the gap 13.

  As shown in FIG. 3, the current sensor 30 in the present embodiment is formed by forming the skirts (31c-31m, 31d-31n) of the core 31 in a bowl shape. As a result, the distance between the two opposite sides (the side consisting of 31c-31e and the side consisting of 31d-31f) among the three sides constituting the U-shape of the core 31 is narrowed, and the first magnetic path is closed. Close to.

  In the current sensor 30 according to the present embodiment, for example, when the current I to be measured flows from the front surface to the back surface of the conductive member 14, a clockwise magnetic field is generated around the conductive member 14 toward the paper surface.

  As described above, the magnetic field has the property of easily passing through a nearby magnetic path, a closed magnetic path, and a magnetic path having a high magnetic permeability (low magnetic resistance). Therefore, the current sensor 30 in the present embodiment uses this property to bring the first magnetic path closer to the closed magnetic path, thereby reducing the magnetic field B2b passing through the second magnetic path, thereby reducing the first magnetic path. The magnetic field B1a passing through the path is increased.

  Thereby, the magnetoelectric conversion element 12 can easily detect the change of the magnetic field B1b passing through the gap 13, and can output an electric signal corresponding to the change to an external device (not shown).

  By the way, depending on the installation location and usage environment of the current sensor 30, a magnetic field B <b> 2 (broken arrow) different from the magnetic field B <b> 1 may converge on the core 31 and pass through. The magnetic field B2 is based on, for example, an external magnetic field generated from an electronic device or a magnetic body disposed in the vicinity of the geomagnetism or the current sensor 30. Since the magnetic field has the properties described above, a part of the external magnetic field (magnetic field B2a) passes through the second magnetic path, and the other part (magnetic field B2b) passes through the first magnetic path. It will be.

  However, in the current sensor 30 according to the present embodiment, even when such an external magnetic field is focused on the core 31, the external magnetic field passes through the first and second magnetic paths based on the above-described properties of the magnetic field. To do. That is, a part of the external magnetic field (magnetic field B2a) passes through the second magnetic path, and the other part (magnetic field B2b) passes through the first magnetic path.

  Therefore, in the current sensor 30 according to the present embodiment, in a part of the core 31, the magnetic path is branched into the first magnetic path and the second magnetic path, thereby generating a magnetic field generated around the conductive member 14. B1 and the external magnetic field pass through the first and second magnetic paths separately. Thereby, magnetic saturation of the core 31 can be prevented.

  The ratio at which the magnetic fields B1 and B2 are separated from the first and second magnetic paths is substantially determined by the permeability ratio (magnetoresistance ratio) of each magnetic path and the distance ratio from the conductive member 14. Therefore, if these ratios are obtained in advance, the current value of the measured current I can be measured based on the magnetic field B1a passing through the gap 13.

  As shown in FIG. 3, the first conductive member 14 can be passed through the core 31 so as to be disposed at a position surrounding the conductive member 14 from a direction substantially perpendicular to the longitudinal direction of the conductive member 14. The gap 15 is formed.

  The width of the first gap 15 (the width between 31 m and 31 n) W ′ is assumed to be wider than the width W of the conductive member 14. Therefore, even when the conductive member 14 through which the current I to be measured flows is disposed in advance in a housing or a storage case (not shown), the core 31 can be disposed at a position surrounding the conductive member 14. That is, when the core 11 is retrofitted, the current sensor 30 can be easily and efficiently retrofitted with the core 31.

  Although the best mode for carrying out the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. is there. For example, the outer shape of the core is not limited to the U shape, and may be a C shape or a U shape. In the invention according to the dependent claims of the present invention, a part of the constituent features of the dependent claims can be omitted.

It is a schematic sectional drawing of the current sensor in the 1st Embodiment of this invention. It is a schematic sectional drawing of the current sensor in the 2nd Embodiment of this invention. It is a schematic sectional drawing of the current sensor in the 3rd Embodiment of this invention. It is a figure which shows the conventional current sensor, (a) is a perspective view, (b) is sectional drawing.

Explanation of symbols

10, 20, 30, 50 ... current sensor, 11, 21, 31, 51 ... core, 12, 52 ... magnetoelectric transducer, 13, 53 ... gap, 14, 54 ... conductive Member, 15... First gap, 26... Low permeability portion (second gap)

Claims (12)

A core that is disposed so as to surround a conductive member through which a current to be measured flows, and that collects a magnetic field generated when the current to be measured flows through the conductive member;
A magnetoelectric conversion element that outputs an electrical signal corresponding to the magnetic field collected by the core;
The core has a first gap through which the conductive member can pass so that the core can be disposed at a position surrounding the conductive member from a direction substantially perpendicular to the longitudinal direction of the conductive member. A magnetic path is branched into a first magnetic path and a second magnetic path, and the magnetoelectric conversion element is provided in one of the branched first and second magnetic paths. Characteristic current sensor. The first magnetic path is located closer to the conductive member than the second magnetic path;
The current sensor according to claim 1, wherein the magnetoelectric conversion element is provided in the first magnetic path.   The current sensor according to claim 1, wherein the second magnetic path is provided in substantially the same plane so as to cover the first magnetic path.   4. The current sensor according to claim 1, wherein the second magnetic path has a low magnetic permeability portion having a lower magnetic permeability than that of the second magnetic path in a part of the second magnetic path.   The current sensor according to claim 4, wherein the low magnetic permeability portion is a second gap.   The current sensor according to claim 1, wherein a width of the first gap is larger than a width of the conductive member. A core of a current sensor that is arranged so as to surround a conductive member through which a current to be measured flows and collects a magnetic field generated by the current to be measured flowing through the conductive member;
In a part of the core, there is a first gap through which the conductive member can be passed so that the conductive member can be disposed at a position surrounding the conductive member from a direction substantially perpendicular to the longitudinal direction of the conductive member. The core of the current sensor, wherein the magnetic path is branched into a first magnetic path and a second magnetic path.   The core of the current sensor according to claim 7, wherein the first magnetic path is located closer to the conductive member than the second magnetic path.   The core of the current sensor according to claim 7 or 8, wherein the second magnetic path is provided in substantially the same plane so as to cover the first magnetic path.   The core of the current sensor according to any one of claims 7 to 9, wherein the second magnetic path has a low permeability portion having a lower permeability than the second magnetic path in a part of the second magnetic path. .   The core of the current sensor according to claim 10, wherein the low magnetic permeability portion is a second gap.   The core of the current sensor according to claim 7, wherein a width of the first gap is larger than a width of the conductive member.

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