A current detection device, system and method

Abstract

The present invention provides a current detection device, system and method, which relate to the field of electromagnetic compatibility testing technology. A current detection device includes a bracket, and also includes an electromagnetic body, a conversion joint and a pointer installed on the bracket. The pointer is rotatably connected to the bracket through a rotating shaft, and the end of the rotating shaft away from the bracket is connected to the electromagnetic body. The electromagnetic body is used to drive the pointer to deflect, and the conversion joint is electrically connected to the electromagnetic body. The conversion joint includes a moving contact and a fixed contact for conducting electricity. The fixed contact is fixedly installed on the bracket, and the moving contact is fixedly connected to the pointer. The pointer is configured to make the moving contact abut against the fixed contact when fully deflected, and the conversion joint is configured to switch the current path to short-circuit the electromagnetic body when the moving contact and the fixed contact are connected. The above-mentioned current detection device is used to measure the standby current of the DUT, and can be directly connected in series with an ammeter with a larger range to measure the working current. The present invention has the effect of continuously measuring the standby current and working current of the DUT to simplify the measurement process.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic compatibility testing, and in particular to a current detection device, system and method. Background Art

[0002] In the automotive electronics industry, electronic devices on cars need to undergo automotive electromagnetic compatibility testing before leaving the factory. In automotive electromagnetic compatibility testing, an anechoic chamber that shields electromagnetic signals is used. The anechoic chamber can shield interference from external electromagnetic waves, and perform radiated radio disturbance and immunity tests on samples placed in the anechoic chamber. Since the anechoic chamber is sensitive to electromagnetic waves emitted by electronic devices, the radiation signals emitted by commonly used electronic multimeters can interfere with and misjudge the test data.

[0003] There are generally two ways to test product current in the existing darkroom: one is to use a mechanical multimeter, which has almost no radiation, but has the problem of being unable to switch ranges continuously. The product under test (DUT for short) uses a μA-level ammeter in standby mode, and an ammeter with a range of A or above is required in working mode. However, the μA-level ammeter and the A-level ammeter cannot be directly connected in series due to the large difference in range. Therefore, it is necessary to use a low-range meter to measure once in standby mode, and then connect the product to be tested to a high-range meter and switch to working mode to measure again, which makes the measurement process cumbersome, and multiple measurements will increase the measurement error. The other is to directly use a digital multimeter dedicated to the darkroom. This type of multimeter is precisely designed to produce low radiation that can meet the radiation noise floor requirements, but the cost of a dedicated multimeter is high, and the price is dozens of times that of a general-purpose electronic multimeter, which is difficult to promote on a large scale. Summary of the invention

[0004] The problem solved by the invention is how to use a mechanical multimeter to continuously measure the standby current and the working current of a DUT.

[0005] In order to solve the above problems, the present invention provides a current detection device, system and method.

[0006] In a first aspect, the present invention provides a current detection device, which adopts the following technical solution:

[0007] A current detection device comprises a bracket, an electromagnetic body, a conversion joint and a pointer installed on the bracket, wherein the pointer is rotatably connected to the bracket via a rotating shaft, an end of the rotating shaft away from the bracket is connected to the electromagnetic body, the electromagnetic body is used to drive the pointer to deflect, and the conversion joint is electrically connected to the electromagnetic body;

[0008] The conversion joint includes a moving contact and a fixed contact for conducting electricity, the fixed contact is fixedly mounted on the bracket, the moving contact is fixedly connected to the pointer, the pointer is configured to make the moving contact abut against the fixed contact when fully deflected, and the conversion joint is configured to short-circuit the electromagnetic body by switching the current path when the moving contact is connected to the fixed contact.

[0009] The beneficial effects of the present invention are as follows: an ordinary mechanical ammeter is modified to switch the current path by setting a conversion joint. The moving contact of the conversion joint is fixed to the pointer, and the fixed contact is fixed to the bracket. When measuring the current, the moving contact rotates synchronously with the deflection of the pointer; when the current reaches or exceeds the maximum range, the pointer is fully deflected, and the moving contact abuts against the fixed contact at this time, thereby connecting the conversion joint to prevent the device from being burned by excessive current. Furthermore, the device is connected in series with another ammeter with a larger range, and the current value of the DUT in the standby state and the working state can be continuously measured. Compared with the prior art, the present device does not need to replace the ammeter to measure the current in the standby state and the working state respectively, which simplifies the measurement steps; at the same time, the present device is modified from an ordinary mechanical ammeter, and the price is only one thousandth of the digital multimeter for darkroom use, which can effectively save economic costs; in addition, the present device also has the advantage of small radiation interference, which can ensure the accuracy of the measurement results.

[0010] Optionally, the conversion connector also includes a permanent magnet and an attraction coil, and the permanent magnet and the attraction coil are respectively arranged on the fixed contact and the moving contact, and the attraction coil is electrically connected to the electromagnetic body. The attraction coil generates magnetism when energized, and the permanent magnet magnetically attracts the attraction coil to make the moving contact press against the fixed contact.

[0011] Optionally, when the current does not reach the maximum range, the suction force generated by the permanent magnet on the attraction coil is smaller than the torque driving the pointer to deflect.

[0012] Optionally, the surfaces of the fixed contact and the movable contact that are in contact with each other are respectively a first abutting surface and a second abutting surface, and the first abutting surface is completely in contact with the second abutting surface.

[0013] Optionally, the first abutting surface is a convex spherical surface, and the second abutting surface is a concave arc surface.

[0014] Optionally, the pointer includes a connecting sleeve and a needle, the needle is vertically fixed to the outer peripheral wall of the connecting sleeve, the connecting sleeve is coaxially nested with the rotating shaft, the rotating shaft is pivotally connected to the electromagnetic body, the connecting sleeve is fixedly connected to the electromagnetic body, and the moving contact is fixedly connected to the outer peripheral wall of the connecting sleeve.

[0015] Optionally, an extension plate is provided between the moving contact and the connecting sleeve, one end of the extension plate is fixed to the connecting sleeve, and the other end is fixedly connected to the moving contact, and the extension plate is used to keep the conversion connector away from the electromagnetic body.

[0016] In a second aspect, the present invention provides a current detection system, which adopts the following technical solution:

[0017] A current detection system includes a first ammeter, a second ammeter, a battery and a product to be tested which are connected in series to form a loop. The ranges of the first ammeter and the second ammeter are of different magnitudes, and the range of the first ammeter is smaller than that of the second ammeter. The first ammeter adopts the current detection device as described above.

[0018] In a third aspect, the present invention provides a current detection method, which adopts the following technical solution:

[0019] A current detection method, using the current detection system as described above, comprises the following steps:

[0020] S1 measurement preparation: provide an anechoic chamber, a radio disturbance device and the current detection system, connect the product to be tested in series with the first ammeter, the second ammeter and the battery in a standby state to form a loop; place the current detection system in the anechoic chamber and turn on the radio disturbance device;

[0021] S2 measures the standby current: reading the measured value of the first ammeter to measure the current size of the product under test in the standby state;

[0022] S3 measures the working current: directly switches the product to be tested to the working state, reads the measurement value of the second ammeter, and measures the current size of the product to be tested in the working state.

[0023] Since the technical improvements and technical effects of the current detection system and method are the same as those of the current detection device, the current detection system and method will not be described in detail.

[0024] Optionally, a noise radiation measuring instrument is provided in the anechoic chamber. Before performing steps S2 and S3, the noise radiation measuring instrument is turned on. When performing steps S2 and S3, the noise radiation of the product to be tested in the standby state and the working state is synchronously measured, and the measured value of the noise radiation is compared with the limit value. When any measured value exceeds the limit value, the ammeter used in this state is replaced, and the above steps S1-S3 are repeated until the noise radiation measurement values ​​do not exceed the limit value during the measurement process, and the current measurement is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1This is a graph showing the noise radiation measurement results when an electronic multimeter is used.

[0026] Figure 2 Schematic diagram of the structure of a current detection device according to an embodiment of the present invention.

[0027] Figure 3 for Figure 2 A partial enlarged view of area A in the middle.

[0028] Figure 4 4 is a circuit diagram of a current detection device according to an embodiment of the present invention.

[0029] Figure 5 Graph showing the relationship between the magnetic force of the permanent magnet and the magnetic gap in an embodiment of the present invention.

[0030] Figure 6 Schematic diagram of the structure of a current detection system according to an embodiment of the present invention.

[0031] Figure 7 4 is a flow chart of the current detection method according to an embodiment of the present invention.

[0032] Figure 8 FIG. 4 is a diagram showing the noise radiation measurement result when the current detection system according to an embodiment of the present invention is used.

[0033] Description of reference numerals:

[0034] 1. Bracket; 11. Shaft; 12. Flange; 13. Mounting plate; 2. Electromagnetic body; 3. Conversion joint; 31. Moving contact; 311. Second abutting surface; 32. Fixed contact; 321. First abutting surface; 33. Permanent magnet; 34. Attraction coil; 35. Extension plate; 4. Pointer; 41. Connecting sleeve; 42. Needle; 5. Rotating shaft; 6. First ammeter; 7. Second ammeter; 8. Battery; 9. Product to be tested; 10. Dial. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0036] The Z axis in the drawings represents the vertical direction, that is, the up and down position, and the positive direction of the Z axis represents the top, and the reverse direction of the Z axis represents the bottom; the X axis in the drawings represents the horizontal direction, and is designated as the front and back position, and the positive direction of the X axis represents the front side, and the reverse direction of the X axis represents the back side; the Y axis in the drawings represents the left and right position, and the positive direction of the Y axis represents the left side, and the reverse direction of the Y axis represents the right side. It should also be noted that the aforementioned Z axis, Y axis, and X axis are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0037] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0038] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0039] Electronic devices in cars need to undergo automotive electromagnetic compatibility testing before leaving the factory. In automotive electromagnetic compatibility testing, an anechoic chamber that shields electromagnetic signals is used. The radiated radio disturbance and immunity test of the sample (DUT for short) is performed in the anechoic chamber. The anechoic chamber can shield the interference of external electromagnetic waves. The anechoic chamber is more sensitive to the electromagnetic waves emitted by the electronic devices in the anechoic chamber. The radiation signals emitted by such devices will interfere with and misjudge the test data. Figure 1 , is the noise radiation measurement result of a commonly used electronic multimeter in an anechoic chamber. In the figure, the horizontal axis is frequency, the vertical axis is noise radiation intensity, the horizontal line Limit represents the limit value, and the asterisk "*" represents the peak frequency point of focus. It can be seen from the figure that the noise radiation intensity of the five peak frequencies of focus is higher than the limit value, so the electronic multimeter cannot be used for current measurement of products in the anechoic chamber.

[0040] In the related art, there are generally two solutions for measuring the current value of products in an anechoic chamber. One is to use a digital multimeter dedicated to the anechoic chamber. The dedicated digital multimeter is precisely designed to produce low radiation and can meet the radiation noise floor requirements, but it is expensive and difficult to popularize, so it is rarely used at present. Another commonly used solution is to use a mechanical multimeter with different ranges to measure multiple times.

[0041] Mechanical multimeters have almost no radiation interference, but due to the large difference between the current values ​​in standby mode and working mode, the same ammeter cannot be used for continuous measurement. In standby mode, μA-level ammeters are generally selected, and in working mode, A-level ammeters are generally selected. The ammeter used in standby mode will burn out directly in working mode. However, using the ammeter used in working mode in standby mode will result in insufficient accuracy and difficult-to-read results. Therefore, the only way is to increase the operation steps and test the standby mode and working mode separately. Therefore, during the test, it is necessary to use a low-range ammeter to measure the current in standby mode, and then use a high-range ammeter to measure the current in working mode. Not only is the operation cumbersome, but the discontinuous test will bring greater measurement errors, resulting in inaccurate measurement results.

[0042] In view of the problems existing in the above-mentioned related technologies, the present invention provides a current detection device, system and method.

[0043] Reference Figure 2 A current detection device provided by an embodiment of the present invention includes a bracket 1, and also includes an electromagnetic body 2, a conversion joint 3 and a pointer 4 installed on the bracket 1. The pointer 4 is rotatably connected to the bracket 1 through a rotating shaft 5. The end of the rotating shaft 5 away from the bracket 1 is connected to the electromagnetic body 2. The electromagnetic body 2 is used to drive the pointer 4 to deflect, and the conversion joint 3 is electrically connected to the electromagnetic body 2.

[0044] Specifically, the electromagnetic body 2 is used to convert electrical energy into mechanical energy to drive the pointer 4 to rotate. The electromagnetic body 2 mainly includes a magnet, an iron core, a rotating coil, a spiral spring, etc., and has no substantial difference in structure and function from the ordinary mechanical ammeter in the prior art, which will not be described here. When in use, the device is installed in a housing with a dial 10, and the dial 10 is provided with scale lines indicating the range. The deflection of the pointer 4 cooperates with the dial 10 to output the current value in the circuit.

[0045] In this embodiment, the projection of the bracket 1 in the XY plane is cross-shaped, and the bracket 1 specifically includes a shaft 11 and a flange 12. The shaft 11 extends along the Y direction, and one end extends into the interior of the electromagnetic body 2 for fixation. The shaft 5 is parallel to the shaft 11 and is located directly above the shaft 11, that is, in the positive direction of the Z axis in the figure. The end of the shaft 11 away from the electromagnetic body 2 is fixedly connected to an upwardly extending mounting plate 13, and the shaft 5 is connected between the mounting plate 13 and the electromagnetic coil of the electromagnetic body 2. The flange 12 is fixed to both sides of the shaft 11 axially symmetrically, and extends along the positive and negative directions of the X axis respectively.

[0046] Reference Figure 3 The conversion joint 3 includes a moving contact 31 and a fixed contact 32 for conducting electricity. The fixed contact 32 is fixedly mounted on the bracket 1. The moving contact 31 is fixedly connected to the pointer 4. The pointer 4 is configured to make the moving contact 31 abut against the fixed contact 32 when fully deflected. The conversion joint 3 is configured to short-circuit the electromagnetic body 2 by switching the current path when the moving contact 31 is connected to the fixed contact 32.

[0047] Specifically, the moving contact 31 is fixed to the pointer 4 and approaches the fixed contact 32 as the pointer 4 deflects. The greater the current, the closer the fixed contact 32 is to the moving contact 31. When the pointer 4 rotates to the full deflection state, the moving contact 31 abuts against the fixed contact 32, and the conversion joint 3 is connected. At this time, the conversion joint 3 and the electromagnetic body 2 are in parallel state, and the entire electromagnetic body 2 is in a short-circuit state, which can prevent the components in the circuit from being damaged after the circuit exceeds the range.

[0048] In this embodiment, the fixed contact 32 is fixedly mounted on the top wall of the right flange 12 of the bracket 1 , and both the fixed contact 32 and the moving contact 31 are connected with wires.

[0049] Reference Figure 3 , Figure 4 In this embodiment, a common mechanical ammeter is modified to add a conversion connector 3 to switch the current path. Figure 4In the figure, "E" represents power supply, "Ⅰ" and "Ⅱ" represent that the DUT can switch between standby and working modes. Fix the moving contact 31 of the conversion connector 3 to the pointer 4, and fix the fixed contact 32 to the bracket 1. When measuring the current, the moving contact 31 rotates synchronously with the deflection of the pointer 4; when the current reaches or exceeds the maximum range, the pointer 4 is fully deflected, and the moving contact 31 abuts against the fixed contact 32, thereby connecting the conversion connector 3 to prevent the device from being burned by excessive current. When the current passing through the electromagnetic body 2 reaches or exceeds the maximum range of the current detection device, the electromagnetic body 2 of the current detection device is short-circuited by the conversion connector 3. At this time, the current passes through the fixed contact 32 and the moving contact 31 of the conversion connector 3 instead of the electromagnetic body 2, so the electromagnetic body 2 will not be burned. At this time, it is equivalent to the current detection device being short-circuited in the circuit to be tested; furthermore, by directly connecting the device in series with another ammeter with a larger range, the current value of the DUT in the standby state and the working state can be continuously measured, and there is no need to remove the small-range ammeter for measuring the standby current from the circuit before measuring the working current.

[0050] Specifically, when the DUT is in standby mode, the current is small, and the detection value of the current detection device is read to ensure the accuracy of the numerical reading. When the DUT is in working mode, the current is large, and the detection value of the ammeter with a larger range can be read to ensure the accuracy of the reading. The current detection device will not be burned out because it is in a short-circuit state. Compared with the prior art, the device does not need to replace the ammeter to measure the current in the standby state and the working state respectively, which simplifies the measurement steps. At the same time, the device is modified from an ordinary mechanical ammeter, and the price is only one thousandth of the digital multimeter used for darkrooms, which can effectively save economic costs and facilitate popularization.

[0051] Reference Figure 3 Optionally, the pointer 4 includes a connecting sleeve 41 and a needle 42, the needle 42 is vertically fixed to the outer peripheral wall of the connecting sleeve 41, the connecting sleeve 41 is coaxially nested with the rotating shaft 5, the rotating shaft 5 is pivotally connected to the electromagnetic body 2, the connecting sleeve 41 is fixedly connected to the electromagnetic body 2, and the moving contact 31 is fixedly connected to the outer peripheral wall of the connecting sleeve 41.

[0052] Specifically, the above-mentioned connection method enables the needle 42 and the moving contact 31 to share the connecting sleeve 41, which can not only realize that the electromagnetic body 2 drives the needle 42 to deflect when the current size is within the measuring range, but also facilitates the magnetic attraction of the moving contact 31 and the fixed contact 32 when the current size exceeds the measuring range, so that the deflection of the moving contact 31 and the needle 42 does not interfere with each other, thereby playing the role of streamlining the structure, so that the rotational cooperation between the connecting sleeve 41 and the rotating shaft 5 can meet the usage requirements in different situations.

[0053] Optionally, the conversion connector 3 also includes a permanent magnet 33 and an attraction coil 34, and the permanent magnet 33 and the attraction coil 34 are respectively arranged on the fixed contact 32 and the moving contact 31, and the attraction coil 34 is electrically connected to the electromagnetic body 2. When the attraction coil 34 is energized, it generates magnetism, and the permanent magnet 33 magnetically attracts the attraction coil 34 to make the moving contact 31 press against the fixed contact 32.

[0054] Specifically, after the conversion joint 3 is connected, the electromagnetic body 2 is short-circuited, and the pointer 4 has a tendency to return to zero. The permanent magnet 33 and the attraction coil 34 can keep the fixed contact 32 and the moving contact 31 in contact after the electromagnetic body 2 is short-circuited and loses its driving force, so that the conversion joint 3 remains connected.

[0055] In this embodiment, an extension plate 35 is provided between the moving contact 31 and the connecting sleeve 41. One end of the extension plate 35 is fixed to the connecting sleeve 41, and the other end is fixedly connected to the moving contact 31. The extension plate 35 is used to keep the conversion connector 3 away from the electromagnetic body 2.

[0056] Specifically, in order to avoid the permanent magnet 33 of the conversion joint 3 and the magnetic components of the electromagnetic body 2 from interfering with each other, the extension plate 35 is provided to keep the permanent magnet 33 and the attraction coil 34 away from the electromagnetic body 2. At the same time, being away from the rotating shaft 5 can also provide the conversion joint 3 with more sufficient installation space, which is convenient for connecting wires and installing and disassembling.

[0057] In this embodiment, one end of the extension plate 35 is welded and fixed to the connecting sleeve 41 , and the moving contact 31 and the attraction coil 34 are adjacently fixed to one end of the extension plate 35 away from the connecting sleeve 41 .

[0058] Optionally, the surfaces of the fixed contact 32 and the movable contact 31 that are in contact with each other are respectively a first abutting surface 321 and a second abutting surface 311 , and the first abutting surface 321 and the second abutting surface 311 are completely in contact with each other.

[0059] In this embodiment, the fixed contact 32 and the movable contact 31 are both cubes, and the first abutting surface 321 and the second abutting surface 311 are both planes with the same shape and size. In other embodiments, the first abutting surface 321 and the second abutting surface 311 may also be other shapes.

[0060] Optionally, the first abutting surface 321 is a convex spherical surface, and the second abutting surface 311 is a concave arc surface.

[0061] Specifically, the cooperation between the convex spherical surface and the concave arc surface can not only satisfy the abutment and conduction, but also play a positioning role to prevent the fixed contact 32 and the moving contact 31 from being offset and causing poor circuit contact.

[0062] Optionally, when the current does not reach the maximum range, the suction force generated by the permanent magnet 33 on the attraction coil 34 is smaller than the torque driving the pointer 4 to deflect.

[0063] Specifically, the selection of the permanent magnet 33 in the conversion connector 3 requires attention. Its magnetism should not interfere with the normal deflection of the pointer 4 within the measuring range, and must meet the accuracy of the device in measuring the current value.

[0064] Reference Figure 5 , the horizontal axis in the figure represents the magnetic gap, that is, the distance between the permanent magnet 33 and the attraction coil 34; the vertical axis represents the magnitude of the magnetic force, that is, the magnetic attraction of the permanent magnet 33 to the attraction coil 34. The curve with a triangle in the figure is the actual value, and the curve with a circle is the simulation value. It can be seen that the actual value and the simulation value curve are close to fitting. Only when the distance between the permanent magnet and the attraction coil is almost zero, the permanent magnet can generate a magnetic attraction force sufficient to drive the moving contact to deflect. Therefore, the magnetic force generated by the permanent magnet 33 in this embodiment will not affect the normal deflection of the pointer 4 within the range.

[0065] Reference Figure 6 An embodiment of the present invention provides a current detection system, comprising a first ammeter 6, a second ammeter 7, a battery 8 and a product to be tested 9 which are sequentially connected in series to form a loop, wherein the ranges of the first ammeter 6 and the second ammeter 7 are of different magnitudes, and the range of the first ammeter 6 is smaller than the range of the second ammeter 7, and the first ammeter 6 is the same as the current detection device described above.

[0066] Specifically, in the figure, "A" represents an ammeter, "DUT" represents the product to be tested 9, and "+" and "-" represent the positive and negative poles of the battery 8, respectively. When performing an electromagnetic compatibility test on the product to be tested 9, a first ammeter 6 with a smaller range is selected to measure the microcurrent of the DUT standby state, and a second ammeter 7 with a larger range is selected to measure the current of the DUT working state. The second ammeter 7 can directly use an existing ordinary mechanical ammeter. Since the first ammeter 6 uses the above-mentioned current detection device, when measuring the working current, the conversion connector 3 is turned on and the first ammeter 6 is short-circuited, so that ammeters of different magnitudes can be used in series. There is no need to replace the ammeter, and the current of the DUT standby state and the working state can be directly and continuously measured.

[0067] In this embodiment, the first ammeter 6 is a μA-class ammeter, and the second ammeter 7 is a Class A ammeter. In other embodiments, the magnitudes of the first ammeter 6 and the second ammeter 7 can be freely changed according to needs.

[0068] Reference Figure 7 , a current detection method provided by an embodiment of the present invention is performed using the current detection system as described above, comprising the following steps:

[0069] S1 measurement preparation: provide an anechoic chamber, a radio disturbance device and the current detection system, connect the product to be tested 9 in series with the first ammeter 6, the second ammeter 7 and the battery 8 in a standby state to form a loop; place the current detection system in the anechoic chamber, and turn on the radio disturbance device.

[0070] S2 measures the standby current: reads the measurement value of the first ammeter 6 to measure the current size of the product to be tested 9 in the standby state.

[0071] S3 measures the working current: directly switches the product to be tested 9 to the working state, reads the measurement value of the second ammeter 7, and measures the current size of the product to be tested 9 in the working state.

[0072] The beneficial effects of the current detection system and the current detection method of this embodiment relative to the prior art are the same as those of the above-mentioned current detection device, and will not be described in detail here.

[0073] Optionally, a noise radiation measuring instrument is provided in the anechoic chamber. Before performing steps S2 and S3, the noise radiation measuring instrument is turned on. When performing steps S2 and S3, the noise radiation of the product to be tested 9 in the standby state and the working state is synchronously measured, and the measured value of the noise radiation is compared with the limit value. When any measured value exceeds the limit value, the ammeter used in this state is replaced, and the above steps S1-S3 are repeated until the noise radiation measurement values ​​do not exceed the limit value during the measurement process, and the current measurement is completed.

[0074] Specifically, the noise radiation measurement results of the standby current and the working current are continuously measured using this method. Figure 8 As shown in the figure, the green line represents the noise radiation intensity in standby mode, the blue line represents the noise radiation intensity in working mode, and the other indicators are the same as Figure 1 It can be seen that the method of continuously measuring the current by connecting the first ammeter 6 and the second ammeter 7 in series can ensure that the noise radiation intensity is lower than the limit value during the entire measurement process, thereby indicating that the above-mentioned current detection device meets the conditions for use in an anechoic chamber, and the current measurement result is accurate and effective.

[0075] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A current detection device, characterized in that: The invention comprises a bracket (1), an electromagnetic body (2) mounted on the bracket (1), a conversion joint (3) and a pointer (4), wherein the pointer (4) is rotatably connected to the bracket (1) via a rotating shaft (5), an end of the rotating shaft (5) away from the bracket (1) is connected to the electromagnetic body (2), the electromagnetic body (2) is used to drive the pointer (4) to deflect, and the conversion joint (3) is electrically connected to the electromagnetic body (2); The conversion joint (3) comprises a movable contact (31) and a fixed contact (32) for conducting electricity, the fixed contact (32) being fixedly mounted on the bracket (1), the movable contact (31) being fixedly connected to the pointer (4), the pointer (4) being configured to make the movable contact (31) abut against the fixed contact (32) when fully deflected, and the conversion joint (3) being configured to short-circuit the electromagnetic body (2) by switching the current path when the movable contact (31) and the fixed contact (32) are connected; The conversion joint (3) further comprises a permanent magnet (33) and an attraction coil (34); the permanent magnet (33) and the attraction coil (34) are respectively arranged on the fixed contact (32) and the moving contact (31); the attraction coil (34) is electrically connected to the electromagnetic body (2); the attraction coil (34) generates magnetism when electricity is supplied, and the permanent magnet (33) magnetically attracts the attraction coil (34) so ​​that the moving contact (31) is pressed against the fixed contact (32); The pointer (4) comprises a connecting sleeve (41) and a needle (42), wherein the needle (42) is vertically fixed to the outer peripheral wall of the connecting sleeve (41), the connecting sleeve (41) is coaxially nested with the rotating shaft (5), the rotating shaft (5) is pivotally connected to the electromagnetic body (2), the connecting sleeve (41) is fixedly connected to the electromagnetic body (2), and the moving contact (31) is fixedly connected to the outer peripheral wall of the connecting sleeve (41); An extension plate (35) is provided between the moving contact (31) and the connecting sleeve (41), one end of the extension plate (35) is fixed to the connecting sleeve (41), and the other end is fixedly connected to the moving contact (31), and the extension plate (35) is used to keep the conversion joint (3) away from the electromagnetic body (2); The current detection device is used to continuously detect the standby current and working current of the sample in the electromagnetic compatibility test. The current detection method includes the following steps: S1. Measurement preparation: providing an anechoic chamber, a radio disturbance device, and a current detection system, wherein the current detection system comprises a first ammeter (6), a second ammeter (7), a battery (8), and a product to be tested (9) which are sequentially connected in series to form a loop, wherein the ranges of the first ammeter (6) and the second ammeter (7) are of different magnitudes, and the range of the first ammeter (6) is smaller than the range of the second ammeter (7), and the first ammeter (6) adopts the current detection device; the product to be tested (9) is connected in series with the first ammeter (6), the second ammeter (7), and the battery (8) in a standby state to form a loop; the current detection system is placed in the anechoic chamber, and the radio disturbance device is turned on; S2, measuring the standby current: reading the measurement value of the first ammeter (6) to measure the current size of the standby state of the product to be tested (9); S3, measuring the working current: directly switching the product to be tested (9) to the working state, reading the measured value of the second ammeter (7), and measuring the current magnitude of the product to be tested (9) in the working state; The anechoic chamber is provided with a noise radiation measuring instrument. Before performing steps S2 and S3, the noise radiation measuring instrument is turned on. When performing steps S2 and S3, the noise radiation of the product to be tested (9) in the standby state and the working state is synchronously measured, and the measured value of the noise radiation is compared with the limit value. When any measured value exceeds the limit value, the ammeter used in this state is replaced, and steps S1-S3 are repeated until the noise radiation measured values ​​do not exceed the limit value during the measurement process, and the current measurement is completed.

2. The current detection device according to claim 1, characterized in that: When the current has not reached the maximum range, the suction force generated by the permanent magnet (33) on the attraction coil (34) is smaller than the torque driving the pointer (4) to deflect.

3. The current detection device according to claim 1, characterized in that: The surfaces of the fixed contact (32) and the movable contact (31) that are in contact with each other are respectively a first abutting surface (321) and a second abutting surface (311), and the first abutting surface (321) and the second abutting surface (311) are completely in contact with each other.

4. The current detection device according to claim 3, characterized in that: The first abutting surface (321) is a convex spherical surface, and the second abutting surface (311) is a concave arc surface.

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