Device and method for measuring horizontal magnetic induction intensity in space area

Abstract

The invention provides a device and method for measuring horizontal magnetic induction intensity in a space area, and the device comprises a magnetic needle which is disposed at the geometric center of a two-dimensional Helmholtz coil and is used for indicating the total magnetic field direction at the geometric center of the two-dimensional Helmholtz coil; the point light source is fixed at the geometric center of the lower surface of the upper plate of the instrument frame and is positioned right above the magnetic needle; the dial disc is arranged at the bottom of the instrument frame and located under the magnetic needle, accurate measurement of the horizontal magnetic induction intensity in a specific space area is achieved, the two-dimensional Helmholtz coil can generate a uniform and controllable magnetic field environment, the magnetic field at the geometric center has high stability and consistency, and the measurement accuracy is improved. Therefore, the measurement accuracy is improved. An optical lever method is adopted to amplify the image of the magnetic needle for reading. And the positions among the point light source, the magnetic needle and the dial disc can be adjusted to change the amplification factor so as to meet different requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetic field measurement, and relates to a device and a method for measuring horizontal magnetic induction intensity in a space area. Background Art

[0002] The measurement of magnetic induction intensity is a crucial technology, which plays an irreplaceable role in many fields. In the field of physical experiments, accurate measurement of magnetic induction intensity is the basis for exploring electromagnetic phenomena and verifying physical laws. Whether studying electromagnetic induction, electromagnetic oscillation, or exploring the influence of magnetic field on the properties of matter, it is inseparable from the accurate measurement of magnetic induction intensity. Scientists can obtain magnetic field data in real time and accurately by using advanced measurement methods, such as magnetometers and Hall sensors, to provide strong support for theoretical research. In the research and development of electronic equipment, the measurement of magnetic induction intensity also plays a pivotal role. The performance of many electronic devices, such as magnetic sensors and magnetic memories, is closely related to the magnetic field. Through the accurate measurement of magnetic induction intensity, engineers can optimize device design, improve product performance, and ensure the stable operation of electronic equipment in complex electromagnetic environments. Industrial magnetic material testing is also an important application field of magnetic induction intensity measurement. In the production process of magnetic materials, strict control of their magnetic properties is essential. By measuring magnetic induction intensity, key parameters such as the magnetization characteristics and saturation magnetic induction intensity of the material can be evaluated, providing a scientific basis for the selection and application of materials. In addition, the measurement of magnetic induction intensity also plays an important role in electromagnetic environment monitoring. With the extensive application of electromagnetic equipment, the problem of electromagnetic pollution has become increasingly prominent. Through real-time monitoring of the magnetic induction intensity in the environment, potential electromagnetic interference problems can be discovered and solved in a timely manner to ensure the safety of human living and working environment.

[0003] Existing magnetic induction intensity measuring instruments, such as high-precision Hall effect sensors and fluxgate sensors, can provide accurate measurement data, but they are usually expensive, complex, and have a limited scope of application. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a device and a method for measuring the horizontal magnetic induction intensity in a spatial area, thereby effectively solving the shortcomings of traditional magnetic induction intensity measurement equipment, such as limited measurement range, weak anti-electromagnetic interference ability, high equipment cost and complex operation.

[0005] The present invention is achieved through the following technical solutions: The present invention provides a device for measuring horizontal magnetic induction intensity in a space region, comprising: Instrument frame, two-dimensional Helmholtz coil, magnetic needle, point light source and graduated disk; The two-dimensional Helmholtz coil is arranged on the top of the instrument frame; The magnetic needle is arranged at the geometric center of the two-dimensional Helmholtz coil, and is used to indicate the direction of the total magnetic field at the geometric center of the two-dimensional Helmholtz coil; The point light source is fixed at the geometric center of the lower surface of the upper plate of the instrument frame and is located directly above the magnetic needle; The graduated disc is arranged at the bottom of the instrument frame and is located directly below the magnetic needle.

[0006] A turntable is installed on the lower surface of the upper plate of the instrument frame, and the turntable includes an inner ring and an outer ring. The inner ring is fixed on the lower surface of the upper plate of the instrument frame, and the inner ring and the outer ring rotate coaxially relative to each other; a single coil is fixed on the outer ring, and the magnetic field generated on the energized axis of the single coil is horizontal and points to the magnetic needle.

[0007] Preferably, the inner ring is provided with 360° scale lines; the direction of the magnetic field generated on the energized axis of the single coil is read according to the scale on the inner ring pointed by the magnetic needle; the magnitude of the magnetic field to be measured generated on the energized axis of the single coil can be calculated from the magnitude of the energized current.

[0008] The inner ring and the outer ring are both provided with perforations, and screws are used to fix the turntable to the lower surface of the upper plate of the instrument frame through the perforations; the turntable is made of aluminum; Preferably, the two-dimensional Helmholtz coil comprises two pairs of orthogonally placed Helmholtz coils, which are used to generate two mutually perpendicular magnetic induction intensities of known magnitude, and the two pairs of orthogonally placed Helmholtz coils are suspended and fixed on the instrument frame by tethers; the Helmholtz coil comprises a single coil and a connecting column, and is bonded with a fixing glue; the single coil consists of a wire frame and a copper wire, and a copper wire with a specific number of turns is wound in the wire frame.

[0009] Preferably, a digital milliammeter is also included to display the current value in the Helmholtz coil. Preferably, four connecting posts are arranged around the two-dimensional Helmholtz coil, and the four connecting posts are horizontally coplanar. By wrapping the four connecting posts with thin wires, a square grid can be formed at the geometric center of the two-dimensional Helmholtz coil, and the magnetic needle is fixed in the grid.

[0010] Preferably, the point light source, the center of the scale disk and the center of the magnetic needle are collinear, and the collinear straight line is along the vertical direction.

[0011] Preferably, the magnetic needle is provided with a transparent shell on the outside and is filled with light-transmitting liquid inside.

[0012] Preferably, the point light source is fixed to the punched position on the lower surface of the upper plate of the instrument frame by a screw-bolt assembly; the scale disc is made of a metal disc with spray-painted scales; the instrument frame is constructed of wooden slats, and the wooden slats are mounted together by angle brackets and screws.

[0013] A method for measuring a device for measuring horizontal magnetic induction intensity in a space region, comprising: S1. Place the horizontal magnetic induction device in the north-south direction, place the magnetic needle in the geometric center of the two-dimensional Helmholtz coil, turn on the point light source and adjust the positions of the magnetic needle, the point light source and the scale disk until the projection of the magnetic needle is magnified and appears in the scale disk, and record the angle indicated by the projection of the magnetic needle at this time; S2, coil L 2 When the power is on, the Biot-Savart law tells us that the coil L 2 After power is applied, a magnetic field B in the east-west direction is generated. 2 , gradually increase the current and observe the angle of deflection of the magnetic needle projection. When the projection angle of the magnetic needle 5 deflects to 45°, stop increasing the current and fine-tune the current until the magnetic needle deflects to 45° accurately. The magnetic induction intensity of the geomagnetic field at this time is the same as that of the Helmholtz coil L 2 The magnetic induction intensity generated is equal, so the magnetic induction intensity of the earth's magnetic field B is obtained. 地磁 ; S3, based on the magnetic field intensity B 地磁 , in the direction of the Earth's magnetic field, the coil L 1 The magnetic field B generated by the current 1 Reinforcement is performed, where the magnitude of the magnetic induction intensity is B 1 -B 地磁 , denoted as ∆B; S4, introduce the magnetic field to be measured, set the coil L in the magnetic field to be measured B" 1 Direction and coil L 2 The component of the direction is B" 1 and B" 2 ; Through the coil L 2 When power is turned on, the deflection angle of the magnetic needle should follow the coil L. 2 The current in the magnetic field increases with the increase of the current, and the current is fine-tuned until the preset deflection angle of the magnetic needle is α. 1 , record the coil L at this time 2 The current in coil L is obtained 2 The magnetic field generated is B 2(1) ; Change coil L again 2 The current size in the magnetic needle is adjusted to a preset deflection angle of α. 2 , record the coil L at this time 2 The current in the coil L is obtained after the current is changed 2 The magnetic field generated is B 2(2) ; The preset deflection angle range is 10° to 80°; Through the magnetic field B 2(1) and magnetic field B2(2) , obtain the coil L for measuring the magnetic field B" 1 Direction and coil L 2 The component of the direction is B" 1 and B" 2 , after vector superposition, the magnetic field to be measured is obtained B"; The coil L 2 It is a coil in the two-dimensional Helmholtz coil that generates a magnetic field perpendicular to the earth's magnetic field; coil L 1 It is a two-dimensional Helmholtz coil that generates a magnetic field parallel to the Earth's magnetic field.

[0014] Preferably, the magnetic field intensity B 地磁 The calculation formula is: tan45°=1=(B 2 / B 地磁 ) The coil L 2 The magnetic field generated is B 2(1) The calculation formula is: tanα 1 =(B 2(1) +B" 2 ) / (B 1 +B" 1 ); After changing the current, coil L 2 The magnetic field generated is B 2(2) The calculation formula is: tanα 2 =(B 2(2) +B" 2 ) / (B 1 +B" 1 ).

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: The invention provides a device for measuring the horizontal magnetic induction intensity in a spatial region, comprising a magnetic needle arranged at the geometric center of a two-dimensional Helmholtz coil, used to indicate the total magnetic field direction at the geometric center of the two-dimensional Helmholtz coil; a point light source is fixed at the geometric center of the lower surface of the upper plate of the instrument frame and is located directly above the magnetic needle; a scale disk is arranged at the bottom of the instrument frame and is located directly below the magnetic needle, so as to realize the accurate measurement of the horizontal magnetic induction intensity in a specific spatial region, and the two-dimensional Helmholtz coil can generate a uniform and controllable magnetic field environment, so that the magnetic field at the geometric center has a high degree of stability and consistency, thereby improving the accuracy of the measurement. As an indicator of the magnetic field direction, the magnetic needle can accurately reflect the total magnetic field direction at the geometric center of the two-dimensional Helmholtz coil, providing a direct physical basis for the measurement. The point light source and the scale disk are used in combination, and the direction change of the magnetic needle is converted into a visual angle change by optical projection, so as to further improve the measurement accuracy and readability. Since the two-dimensional Helmholtz coil can generate magnetic fields of different strengths and directions, the device can meet the measurement requirements of the horizontal magnetic induction intensity in different spatial regions. The design of the graduated disk allows the measurement results to be directly expressed in the form of angles or values, which is convenient for comparison with various standards or specifications. The design structure of the present invention is simple, and the only energized working device is a Helmholtz coil. Therefore, the device can generate less interference, and its anti-interference ability is significantly improved compared to traditional devices. Anti-interference tests were carried out on mobile phones, laptops and other devices at work, and it was found that the messy magnetic fields in life have almost no effect on the experimental results. The design of the device enhances the resistance to external electromagnetic interference. In a complex electromagnetic environment, the device can still maintain high stability and measurement accuracy, effectively avoiding data distortion and measurement errors.

[0016] The present invention also provides a method for measuring the horizontal magnetic induction intensity device in a spatial area, which uses a method of combining magnetic needle deflection and optical lever amplification to measure the magnetic field. The measurement accuracy and measurement range of the device of the present invention change with the change of the reinforced magnetic field. The optical lever method is used to amplify the image of the magnetic needle for reading. The position between the point light source, the magnetic needle, and the scale disk can be adjusted to change the magnification to meet different needs; the device adopts a non-contact measurement method to avoid errors and interference caused by contact and improve the reliability of the measurement. Key components such as the magnetic needle and the point light source are all made of high-precision and high-stability components to ensure the long-term stability and reliability of the device. In experimental teaching and daily applications, there is a huge market demand for magnetic induction intensity measurement equipment with high cost performance, flexible measurement range, easy operation and moderate accuracy.

[0017] Furthermore, the structural design of the present invention is simple, and only includes simple basic components such as wire frame, copper wire, power supply, metal scale disc, compass, etc. The operation process is simpler than that of traditional magnetic induction intensity measurement equipment. It only requires turning the power adjustment knob, observing the rotation direction of the magnetic needle, and recording the digital display milliampere value. The simple operation avoids complicated debugging and calibration steps. Users do not need to have professional skills to operate it, which is particularly suitable for use in teaching experiments or environmental measurements. This simplified operation process not only improves the convenience of use, but also reduces the errors caused by improper human operation.

[0018] Furthermore, compared with equipment that relies on high-precision sensors, the present invention uses low-cost components, reducing the overall cost. Components such as magnetic needles, wireframe copper wires, and light sources can all be purchased on the market at a relatively low price. According to statistics, the cost of a complete instrument assembled directly from the market is about 500 yuan, while the cost of bulk purchases or factory production of each component will be lower. This improvement enables the device to have a high cost-effectiveness while ensuring accuracy, and is suitable for the needs of college physics experiment teaching, environmental measurement, and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of angle 1 of a device for measuring horizontal magnetic induction intensity in a space area; Figure 2 Angle 2 schematic diagram of a device for measuring horizontal magnetic induction intensity in a space area; Figure 3 Angle 3 schematic diagram of a device for measuring horizontal magnetic induction intensity in a space area; Figure 4 This is a schematic diagram of the instrument framework; Figure 5 It is a schematic diagram of the scale disk; Figure 6 It is a schematic diagram of a two-dimensional Helmholtz coil; Figure 7 Schematic diagram of a single coil of a two-dimensional Helmholtz coil; Figure 8 A three-dimensional solid bottom view of a device for measuring horizontal magnetic induction intensity in a space area; Fig. 9 A three-dimensional solid partial diagram of a device for measuring horizontal magnetic induction intensity in a space area; Fig.10 A three-dimensional solid side view of a device for measuring horizontal magnetic induction intensity in a space area; Fig.11 The minimum measurement accuracy and measurement range data diagram corresponding to the middle reinforced magnetic field of Example 1; Fig.12 1 is a test data diagram of the magnetic field to be measured in Example 1; In the figure: 1-instrument frame, 2-two-dimensional Helmholtz coil, 3-digital milliammeter, 4-tether, 5-magnetic needle 5, 6-scaled disk, 7-point light source, 8-angle code, 9-wooden slats, 10-single coil, 11-connecting column, 12-copper wire 12, 13-wire frame, 14-turntable, 15-power supply. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0021] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0022] The device for measuring horizontal magnetic induction intensity in a space region of the present invention comprises: Instrument frame 1: The instrument frame 1 material is made of wooden strips 9, and its connection is completed by angle brackets 8 and screws, such as Figure 4 As shown. There are openings at specific locations. Its function is to carry other devices and connect all devices to form an integrated instrument. Figure 1 and Figure 2 shown.

[0023] Two-dimensional Helmholtz coil 2: Two-dimensional Helmholtz coil 2 consists of two pairs of orthogonally placed Helmholtz coils, such as Figure 6 The two-dimensional Helmholtz coil 2 includes a coil L that generates a magnetic field perpendicular to the earth's magnetic field. 2 The coil L in the two-dimensional Helmholtz coil 2 generates a magnetic field parallel to the earth's magnetic field. 1 Its location is as follows Figure 1 and Figure 3 As shown. The fixing method is to suspend and fix it through a tether 4. Its function is to generate two mutually perpendicular magnetic induction intensities with known magnitudes.

[0024] Its working principle is that electric current generates magnetic field, that is, Biot-Savart law:

[0025] In the formula μ 0 is the magnetic permeability of vacuum medium, I is the current magnitude, dl is the length element, r is the distance from the source point to the field point.

[0026] The magnetic induction intensity generated by the Helmholtz coil at the center of its axis can be expressed by the following formula:

[0027] In the formula μ 0 is the magnetic permeability of vacuum medium, I is the current magnitude, N is the number of coil turns, R is the coil radius.

[0028] The Helmholtz coil is composed of two single coils 10 and two connecting posts 11, which are connected by adhesive bonding. Figure 7 The single coil 10 is composed of a wire frame 13 and a copper wire 12, and is composed by winding a specific number of turns of the copper wire 12 in the wire frame 13, such as Figure 5 The two-dimensional Helmholtz coil 2 is also fixed in the center below the upper plate. The four connecting posts 11 of the two-dimensional Helmholtz coil 2 are horizontally coplanar. The four connecting posts 11 are surrounded by fishing lines to form a square grid at the geometric center of the two-dimensional Helmholtz coil 2, and the magnetic needle 5 is fixed in the grid. At this point, it can be determined that the positions of the point light source 7 and the magnetic needle 5 can be determined to be vertically colinear.

[0029] Magnetic needle 5 with transparent shell: It consists of a transparent shell and an internal magnet, such as Figure 8 Its position is at the geometric center of the two-dimensional Helmholtz coil 2, as shown in Figure 1 and Figure 8 The fixing method is towing with a thin wire, and the working principle is that the force direction of the magnet in the magnetic field is parallel to the magnetic field direction, and its function is to indicate the total magnetic field direction at the geometric center of the two-dimensional Helmholtz coil 2.

[0030] Point light source 7: Its position is as follows Fig. 9 As shown. It is fixed in the punching position of the instrument frame 1 by a screw bolt structure. Its function is to illuminate the magnetic needle 5 so that it is enlarged and projected on the scale disk 6. The point light source 7 is fixed at the geometric center of the lower surface of the upper plate of the instrument frame 1.

[0031] Scale disc 6: It is made of a metal disc with scale sprayed on it, such as Figure 5 Its location is shown in Figure 1 and Fig.10 As shown, its function is to read the indicated angle of the projection image of the magnetic needle 5.

[0032] The point light source 7, the center of the scale disk 6, and the center of the magnetic needle 5 are collinear, and the collinear straight line is in the vertical direction. In this way, the light emitted by the point light source 7 can be irradiated onto the scale disk 6 through the magnetic needle 5. The pointer of the magnetic needle 5 is opaque, and the outer shell and the liquid filled inside are translucent, so that the image of the magnetic needle 5 can be observed from the scale disk 6. The scale disk 6, the magnetic needle 5, and the point light source 7 are vertically collinear, so that it can be ensured that the image of the magnetic needle 5 on the scale disk 6 is always the same as the direction indicated by the magnetic needle 5, and then the deflection angle of the magnetic needle 5 can be read by the deflection of the image of the magnetic needle 5 on the disk.

[0033] Digital milliampere meter 3: Figure 1 and Figure 8 Its function is to display the current value in the Helmholtz coil in order to calculate the corresponding magnetic field intensity.

[0034] The power supply 15 provides power to the device for measuring the horizontal magnetic induction intensity in the space area.

[0035] Tether 4: Do not use metal ropes, just ensure the strength. Its position is as follows Figure 8 Its function is to fix the Helmholtz coil and the magnetic needle 5, and fishing line is generally used; Turntable 14: An aluminum turntable 14 is installed on the lower surface of the upper plate of the instrument frame 1. It consists of an inner ring and an outer ring, and the inner ring and the outer ring can rotate coaxially relative to each other. There are four through holes on the inner and outer rings of the turntable 14 respectively. Through the four through holes of the inner ring, the turntable 14 can be fixed to the lower surface of the upper plate of the instrument frame 1 with screws, and the turntable 14 is fixed in the center. There are 360° scale lines on the inner ring. A single coil 10 is fixed to the outer ring through the through holes of the outer ring. The direction of the magnetic field generated on the axis of the single coil 10 when it is energized is horizontal and points to the magnetic needle 5. The outer ring can rotate relative to the inner ring, which causes the single coil 10 to rotate accordingly. The direction of the magnetic field generated on its axis can be read according to the scale on the inner ring. The magnitude of the magnetic field generated on its axis can be calculated by the magnitude of the current passed through. The magnetic field generated by the single coil 10 is generally used as the magnetic field to be measured; The specific steps are as follows: 1. Preparation: In order to introduce the geomagnetic field into the experiment and reduce errors, the horizontal magnetic induction intensity device is first placed in the north-south direction, the experimental instruments and components are checked for integrity, and the lines are connected and checked for correctness.

[0036] 2. Measure the Earth's magnetic field B 地磁 : The purpose of this experiment is to measure the horizontal magnetic induction intensity of the magnetic field. The magnetic induction intensity of the geomagnetic field is about 0.3Gs-0.6Gs, which is 3*10^-5T to 6*10^-5T. The specific magnetic induction intensity of the geomagnetic field should be determined according to the local longitude and latitude and various conditions. Although the magnetic induction intensity of the geomagnetic field is not large, it will cause errors in the measurement. Therefore, before we actually measure the magnetic field, we need to measure the horizontal magnetic induction intensity of the local geomagnetic field first. The default indication direction of the compass is the direction of the geomagnetic field.

[0037] The coil in the two-dimensional Helmholtz coil 2 that generates a magnetic field parallel to the earth's magnetic field is L 1 , the coil that generates a magnetic field perpendicular to the Earth's magnetic field is L 2 . Place the magnetic needle 5 at the geometric center of the two-dimensional Helmholtz coil 2, turn on the point light source 7 and adjust the positions of the magnetic needle 5, the point light source 7 and the scale disk 6 until the projection of the magnetic needle 5 is correctly enlarged and displayed in the scale disk 6. When there is no external magnetic field, the magnetic needle 5 should naturally point to the north and south, and record the angle indicated by the pointer projection at this time. Give the coil L 2 When the power is on, the Biot-Savart law tells us that the coil L 2 After power is applied, a magnetic field B in the east-west direction is generated. 2 . Gradually increase the current and observe the angle of the pointer projection. When the pointer projection angle deflects 45°, stop increasing the current and fine-tune the current until it deflects 45° accurately. Because at this time, there are only the geomagnetic field and L at the magnetic needle 5. 2 The coil generates a magnetic field, and the two magnetic fields are perpendicular to each other, so when the magnetic needle 5 deflects 45°, according to the trigonometric function relationship: tan45°=1=(B 2 / B 地磁 ) Know the magnetic field intensity and coil L at this time 2 The magnetic induction intensity generated is equal. Read the current at this time and record it as i 2 According to formula (2), we can know that L 2 The magnetic induction intensity generated by the coil. At this time, the magnetic induction intensity of the earth's magnetic field is equal to the coil L 2 The magnitude of the magnetic induction intensity generated is denoted by B 地磁 The measurement of the magnetic field intensity is completed. Close the coil L 2 power supply.

[0038] 3. Strengthen the Earth’s magnetic field Coil L 1 The direction of the magnetic field generated is parallel to the direction of the earth's magnetic field. The magnetic induction intensity of the earth's magnetic field is slightly smaller. In the method of measuring the magnetic field with a magnetic needle 5, although the deflection angle 0 to 90° corresponds to L 2The magnetic induction intensity of the generated magnetic field is 0~∞. But in practice, when the angle is close to 90°, the angle change caused by a large magnetic field change is very small, which makes the accurate measurement range less than 90°. In order to improve the accuracy of the measurement, we stipulate that the deflection of the magnetic needle 5 is 10° to 80° as the high-precision range. In order to increase the measurement range of the instrument, we use coil L in the direction of the geomagnetic field. 1 The magnetic field generated by the power supply is reinforced. In different required ranges, the reinforced magnetic field can be customized as needed. The larger the reinforced magnetic field, the larger the range. The reinforced magnetic field needs to be several times larger than the magnetic field to be measured, so that the angle deflection is not large after the magnetic field to be measured is introduced. The reinforced magnetic field is recorded as B 1 In the previous step, the magnetic induction intensity of the earth's magnetic field has been measured to be B 地磁 The magnetic induction intensity we need is B 1 , so the magnetic induction intensity that needs to be strengthened is B 1 -B 地磁 , denoted as ∆B, then the current that can generate ∆B is obtained from the formula, denoted as i 1 . Give coil L 1 Pass the calculated constant current i 1 , and keep it powered on.

[0039] 4. Measure the magnetic field to be measured First, introduce the magnetic field to be measured. Assume that the L 1 Direction and L 2 The component of the direction is B" 1 and B" 2 From the above, we can get the magnetic field intensity B 地磁 and L 1 The sum of the coil magnetic induction intensity ∆B is recorded as the reinforcing magnetic field B 1 , put L 2 The magnetic field generated by the coil is denoted as B 2 .

[0040] After the magnetic field to be measured is introduced, there are two magnetic fields at the magnetic needle 5: the reinforcing magnetic field B 1 , the magnetic field to be measured B". Under normal circumstances, the magnetic needle 5 is no longer pointing to the north-south direction. Open L 2 The power supply of the coil is connected so that the current flowing through it increases slowly from 0. At this time, it should be noted that the deflection angle of the magnetic needle 5 should increase with the change of L 2 When the magnetic needle 5 deflects to the high-precision range, fine-tune the current until the pointer points to a full scale, and record the deflection angle of the magnetic needle 5 at this time, which is α 1 . Record this time L 2 The current in the coil is denoted by i 2 According to the formula, we can know that L 2 The magnetic field generated by the coil is L 2The magnetic field generated by the coil is B 2(1) . Then the following relationship can be obtained based on the trigonometric function relationship: tanα 1 =(B 2(1) +B" 2 ) / (B 1 + B" 1 ) Change L again 2 The current in the coil is adjusted until the magnetic needle 5 deflects to another position within the high-precision range. The current is fine-tuned until the pointer points to a full scale. The deflection angle of the magnetic needle 5 at this time is recorded as ɑ 2 . Record this time L 2 The current in the coil is denoted by i 2 According to the formula, we can know that L 2 The magnetic field generated by the coil is L 2 The magnetic field generated by the coil is B 2(2) . Then, based on the trigonometric function relationship, the following relationship can be obtained: tanα 2 =(B 2(2) +B" 2 ) / (B 1 + B" 1 ) Combining the above two equations, we can solve B" 1 and B" 2 , and then B" 1 and B" 2 The measured value can be obtained by vector superposition.

[0041] The device and method for measuring the horizontal magnetic induction intensity in a space region of the present invention have the following advantages: Unique measuring method: The present invention adopts the method of combining magnetic needle deflection and optical lever amplification to measure the magnetic field.

[0042] The measurement accuracy and measurement range are adjustable: the measurement accuracy and measurement range of the device of the present invention change with the change of the reinforced magnetic field.

[0043] The magnification of the magnetic needle projection image is controllable: the device of the present invention uses the optical lever method to magnify the image of the magnetic needle for reading. The position between the point light source, the magnetic needle, and the scale disk can be adjusted to change the magnification to meet different needs; Simplify operation and improve ease of use: The structural design of the present invention is simple, and it only includes simple basic components such as wire frame, copper wire, power supply, metal scale disc, compass, etc. The operation process is simpler than that of traditional magnetic induction intensity measurement equipment. It only requires simple operations such as turning the power adjustment knob, observing the direction of rotation of the pointer, and recording the digital display milliampere reading, avoiding complicated debugging and calibration steps. Users do not need to have professional skills to operate it, which is particularly suitable for use in teaching experiments or environmental measurements. This simplified operation process not only improves the ease of use, but also reduces errors caused by improper human operation.

[0044] Low cost and wide applicability: Compared with equipment that relies on high-precision sensors, the present invention uses low-cost components, which reduces the overall cost. Components such as magnetic needles, wireframe copper wires, and light sources can be purchased at low prices in the market. According to statistics, the cost of a complete instrument assembled directly from the market is about 500 yuan, while the cost of bulk purchases or factory production of each component will be lower. This improvement enables the device to have a high cost-effectiveness while ensuring accuracy, and is suitable for the needs of college physics experiment teaching, environmental measurement, etc.

[0045] Strong anti-interference ability: The design structure of the present invention is simple, and the only energized working device is the Helmholtz coil. Therefore, the device can generate less interference, and its anti-interference ability is significantly improved compared with traditional devices. Anti-interference tests were carried out on mobile phones, laptops and other devices at work, and it was found that the chaotic magnetic fields in life have almost no effect on the experimental results. The design of the device enhances the resistance to external electromagnetic interference. In a complex electromagnetic environment, the device can still maintain high stability and measurement accuracy, effectively avoiding data distortion and measurement errors.

[0046] Example 1 Take the measurement of weak magnetic field as an example: the parameters of the Helmholtz coil L1 used in the experiment are: the number of turns is 120, and the effective radius is 13.2cm. 2 Parameters: Number of turns is 100 and effective radius is 11cm.

[0047] First, connect the power supply and lines of each electrical appliance.

[0048] Place the magnetic needle 5 at the geometric center of the two-dimensional Helmholtz coil 2, turn on the point light source 7, and adjust the position of the scale disk 6 until the projection is clear and centered. Rotate the scale disk 6 so that the north-pointing pointer of the magnetic needle 5 points to the "0" scale.

[0049] Feed coil L 2Turn on the power and gradually increase the current while observing the angle of the pointer projection. When the pointer projection angle deflects 45°, stop increasing the current and fine-tune the current until it deflects 45° accurately. Record the current i=39.85mA at this time, and calculate L by the formula 2 The magnetic induction intensity B generated by the coil 2 =0.326 Gs. B 2 Substitute the following relationship: tan45°=1=(B 2 / B 地磁 ) The magnetic induction intensity B of the Earth's magnetic field can be obtained 地磁 =0.326Gs. Close L 2 Coil power supply.

[0050] If the reinforced magnetic field is specified to be 10Gs, then the coil L 1 The magnetic induction intensity required to be generated is ∆B=B 1 -B 地磁 =9.674Gs, and L 1 The coil needs to pass a current of 1182.7 mA. 1 The coil is energized and the current is kept constant.

[0051] A weak magnetic field is generated by the current-carrying single coil 10. The magnitude of the magnetic field generated by the current-carrying single coil 10 on its axis can be derived from the Biot-Savart law, and the magnitude is:

[0052] Where μ 0 is the magnetic permeability of the vacuum medium, I is the current, a is the distance from a point on the axis to the center of the coil, N is the number of turns of the coil, and R is the radius of the coil.

[0053] A single current-carrying coil 10 with 120 turns, a radius of 13.2 cm, and a current of 144.1 mA is placed near the Helmholtz coil, with its center 7 cm away from the magnetic needle 5, and placed vertically, and the angle is adjusted so that the direction of the magnetic field generated is 30° north-east. In this way, the magnetic field to be measured is introduced, and its calculated theoretical value is recorded as B'=4.30Gs, and its direction is recorded as θ, which is 30° north-east.

[0054] Open L 2 The power supply of the coil causes the current flowing through it to increase slowly from 0. At this time, the deflection angle of the magnetic needle 5 increases with L 2 When the magnetic needle 5 deflects 45°, the deflection angle of the magnetic needle 5 is α 1 =45°. Record the coil L at this time 2 The current in it is recorded as i2 =1400.44mA. According to the formula, we can know that L 2 The magnetic field generated by the coil is L 2 The magnetic field generated by the coil is B 2(1) =11.455Gs. Based on the trigonometric function relationship, the following relationship can be obtained: tanα 1 =(B 2(1) + B" 2 ) / (B 1 + B" 1 ) Change L again 2 The magnitude of the current in the coil. When the magnetic needle 5 deflects 60°, record the deflection angle of the magnetic needle 5 at this time, which is ɑ 2 =60°. Record L at this time 2 The current in the coil is denoted by i 2 =2617.13. According to the formula, we can know that L 2 The magnetic field generated by the coil is L 2 The magnetic field generated by the coil is B 2(2) =21.407Gs. Then, based on the trigonometric function relationship, the following relationship can be obtained: tanα 2 =(B 2(2) + B" 2 ) / (B 1 +B" 1 ) Combining the above two equations, we can solve B" 1 =3.595 Gs and B" 2 =2.14 Gs, then B" 1 and B" 2 The vector superposition can obtain the measured magnetic field magnetic induction intensity B"=4.1837 Gs. Its direction can be obtained by the following formula:

[0055] Substituting the numerical value into the calculation, we know that its direction is 30.764° north-east.

[0056] After calculation, the relative error of magnetic induction intensity is ᵟ= ×100%=2.7% The absolute error in direction is θ'-θ=0.764° The measurement accuracy and measurement range of this experiment will change with the change of the reinforced magnetic field. Moreover, under the same reinforced magnetic field conditions, the measurement accuracy and measurement range will also change with the change of the size and direction of the magnetic field to be measured.

[0057] The experiment shows the minimum measurement accuracy and measurement range corresponding to the partial enhanced magnetic field Fig.11 and Fig.12 .

[0058] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0059] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be a central component at the same time. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component at the same time.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0061] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the drawings and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A device for measuring horizontal magnetic induction intensity in a space area, characterized in that: include, Instrument frame (1), two-dimensional Helmholtz coil (2), magnetic needle (5), point light source (7) and graduated disk (6); The two-dimensional Helmholtz coil (2) is arranged on the top of the instrument frame (1); The magnetic needle (5) is arranged at the geometric center of the two-dimensional Helmholtz coil (2) and is used to indicate the direction of the total magnetic field at the geometric center of the two-dimensional Helmholtz coil (2); The point light source (7) is fixed at the geometric center of the lower surface of the upper plate of the instrument frame (1) and is located directly above the magnetic needle (5); The graduated disk (6) is arranged at the bottom of the instrument frame (1) and is located directly below the magnetic needle (5); A turntable (14) is mounted on the lower surface of the upper plate of the instrument frame (1), the turntable (14) comprising an inner ring and an outer ring, the inner ring being fixed to the lower surface of the upper plate of the instrument frame (1), the inner ring and the outer ring being coaxially rotated relative to each other; a single coil (10) is fixedly mounted on the outer ring, the magnetic field generated on the energized axis of the single coil (10) being horizontal and pointing toward the magnetic needle (5).

2. A device for measuring horizontal magnetic induction intensity in a space region according to claim 1, characterized in that: The inner ring is provided with 360° scale lines; the direction of the magnetic field generated on the energized axis of the single coil (10) is read according to the scale on the inner ring indicated by the magnetic needle (5); the magnitude of the magnetic field to be measured generated on the energized axis of the single coil (10) can be calculated from the magnitude of the energized current; The inner ring and the outer ring are both provided with through holes, and screws are used to fix the turntable (14) to the lower surface of the upper plate of the instrument frame (1) through the through holes; the turntable (14) is made of aluminum.

3. The device for measuring horizontal magnetic induction intensity in a space region according to claim 1, characterized in that: The two-dimensional Helmholtz coil (2) comprises two pairs of orthogonally placed Helmholtz coils, which are used to generate two mutually perpendicular magnetic induction intensities of known magnitude, and the two pairs of orthogonally placed Helmholtz coils are suspended and fixed on the instrument frame (1) via a tether (4); the Helmholtz coil comprises a single coil (10) and a connecting column (11), and is bonded with a fixing adhesive; the single coil (10) is composed of a wire frame (13) and a copper wire (12), and is wound in the wire frame (13) by a copper wire (12) with a specific number of turns.

4. The device for measuring horizontal magnetic induction intensity in a space region according to claim 3, characterized in that: It also includes a digital milliammeter (3) for displaying the current value in the Helmholtz coil.

5. The device for measuring horizontal magnetic induction intensity in a space region according to claim 1, characterized in that: Four connecting posts (11) are arranged around the periphery of the two-dimensional Helmholtz coil (2), and the four connecting posts (11) are horizontally coplanar. By wrapping the four connecting posts (11) with thin wires, a square grid can be formed at the geometric center of the two-dimensional Helmholtz coil (2), and the magnetic needle (5) is fixed in the grid.

6. The device for measuring horizontal magnetic induction intensity in a space region according to claim 1, characterized in that: The point light source (7), the center of the scale disk (6) and the center of the magnetic needle (5) are collinear, and the collinear straight line is along the vertical direction.

7. The device for measuring horizontal magnetic induction intensity in a space region according to claim 1, characterized in that: The magnetic needle (5) is provided with a transparent shell on the outside and is filled with light-transmitting liquid inside.

8. The device for measuring horizontal magnetic induction intensity in a space region according to claim 1, characterized in that: The point light source (7) is fixed to a punched position on the lower surface of the upper plate of the instrument frame (1) by means of a screw and bolt assembly; the scale disc (6) is made of a metal disc with a spray-painted scale; the instrument frame (1) is constructed of wooden slats (9), and the wooden slats (9) are mounted together by means of angle brackets (8) and screws.

9. A method for measuring a device for measuring horizontal magnetic induction intensity in a space region, based on the device for measuring horizontal magnetic induction intensity in a space region according to any one of claims 1 to 8, characterized in that: include: S1. Place the horizontal magnetic induction device in the north-south direction, place the magnetic needle (5) at the geometric center of the two-dimensional Helmholtz coil (2), turn on the point light source (7) and adjust the positions of the magnetic needle (5), the point light source (7) and the scale disk (6) until the projection of the magnetic needle (5) is magnified and appears in the scale disk (6), and record the angle indicated by the projection of the magnetic needle (5) at this time; S2. Energize coil L2. According to the Biot-Savart law, coil L2 can generate a magnetic field B2 in the east-west direction after being energized. Gradually increase the current and observe the angle deflection of the projection of the magnetic needle (5). When the projection angle of the magnetic needle (5) is deflected to 45°, the current is stopped from being increased and the current is fine-tuned until the magnetic needle (5) is accurately deflected to 45°. At this time, the magnetic induction intensity of the geomagnetic field is equal to the magnetic induction intensity generated by the Helmholtz coil L2, thereby obtaining the magnetic induction intensity B of the geomagnetic field. 地磁 ; S3, based on the magnetic field intensity B 地磁 , the magnetic field B1 generated by the coil L1 is reinforced in the direction of the earth's magnetic field, where the magnitude of the reinforced magnetic induction intensity is B1-B 地磁 , denoted as ∆B; S4, introducing the magnetic field to be measured, setting the components of the magnetic field B" in the direction of coil L1 and the direction of coil L2 to be B"1 and B"2; By energizing the coil L2, the deflection angle of the magnetic needle (5) should increase as the current in the coil L2 increases. The current is fine-tuned until the preset deflection angle of the magnetic needle (5) is α1. The current in the coil L2 at this time is recorded to obtain the magnetic field B generated by the coil L2. 2(1) ; Change the current in coil L2 again, fine-tune the current until the preset deflection angle of the magnetic needle (5) is α2, record the current in coil L2 at this time, and obtain the magnetic field B generated by coil L2 after the current is changed 2(2) ; The preset deflection angle range is 10° to 80°; Through the magnetic field B 2(1) and magnetic field B 2(2) , the components of the coil L1 direction and the coil L2 direction of the magnetic field B" are obtained as B"1 and B"2, and the magnetic field to be measured B" is obtained after vector superposition; The coil L2 is a coil in the two-dimensional Helmholtz coil (2) that generates a magnetic field perpendicular to the earth's magnetic field; the coil L1 is a coil in the two-dimensional Helmholtz coil (2) that generates a magnetic field parallel to the earth's magnetic field.

10. The method for measuring the horizontal magnetic induction intensity device in a measuring space area according to claim 9, characterized in that: The magnetic field intensity B 地磁 The calculation formula is: <h2 style=";text-align:left;direction:ltr">tan45°=1=(B2 / B<h2 style=";text-align:left;direction:ltr"> 地磁 <h2 style=";text-align:left;direction:ltr"> ); The magnetic field B generated by the coil L2 2(1) The calculation formula is: tanα1=(B 2(1) +B"2) / (B1+B"1); The magnetic field B generated by the coil L2 after the current is changed 2(2) The calculation formula is: tanα2=(B 2(2) +B"2) / (B1+B"1)。

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