Devices and equipment for measuring the resistance value of milliohms-level resistors

Abstract

The present invention relates to a resistance value measuring device of a milliohm resistor, comprising: a first current input port, a first voltage output port, a first radio frequency connector, a second radio frequency connector, a four-pole ten-position switch and a loop structure resistor; the input end of the first radio frequency connector is connected to the first current input port, the input end of the second radio frequency connector is connected to a voltage sampling end of the first order of magnitude, the output end of the first radio frequency connector and the output end of the second radio frequency connector are respectively connected to the input end of the four-pole ten-position switch, and the four-layer interface of one gear position of the four-pole ten-position switch is respectively connected to the current high end of the loop structure resistor, the current low end of the loop structure resistor, the voltage high end of the loop structure resistor and the voltage low end of the loop structure resistor; the embodiment of the present invention also provides a resistance value measuring device of a resistor, which effectively solves the problem that it is difficult to measure smaller mΩ AC and DC resistance values ​​in the prior art.

Description

Technical Field

[0001] The invention relates to the field of resistance measurement, and in particular to a resistance value measuring device and resistance value measuring equipment for milliohm-level resistance. Background Art

[0002] The structure of the current AC / DC resistance box follows the simple series structure of the DC resistance box, except that the DC resistance element is replaced by the AC resistance element. The frequency response level of the AC resistance basically depends on the frequency response of the resistance element itself and whether the internal shielding measures are perfect. The influence of the resistor's structural layout and the voltage and current loop routing on the small AC signal is not considered at all. There is no low distributed parameter structure specially designed for the AC broadband characteristics. Therefore, the resistance value range of the existing AC / DC resistance box can only be limited to the order of Ω to the order of MΩ, and it is difficult to measure smaller AC / DC resistance values ​​of the order of mΩ. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a resistance measurement device and a resistance measurement equipment for milliohm-level resistors, which effectively solves the problem that it is difficult to measure smaller mΩ-level AC and DC resistance values ​​in the prior art.

[0004] To achieve the above object, the present invention can be implemented through the following technical solutions:

[0005] A resistance measuring device for a milliohm-level resistor, comprising:

[0006] A first current input port, a first voltage output port, a first radio frequency connector, a second radio frequency connector, a four-pole ten-position switch, and a loop structure resistor corresponding to the interface of the four-pole ten-position switch;

[0007] The first current input port is connected to the input end of the first RF connector, and the first voltage output port is connected to the output end of the second RF connector;

[0008] The first end of the four-pole ten-position switch and the second end of the four-pole ten-position switch are connected to the output end of the first RF connector, the third end of the four-pole ten-position switch and the fourth end of the four-pole ten-position switch are connected to the input end of the first RF connector, and the four-layer interface of one gear position of the four-pole ten-position switch is respectively connected to the current high end of the loop structure resistor, the current low end of the loop structure resistor, the voltage high end of the loop structure resistor, and the voltage low end of the loop structure resistor;

[0009] The loop structure resistor adopts a resistance wire material with a temperature coefficient of less than 50 ppm / °C and an expansion coefficient of less than 30 ppm / °C within a temperature range of 20°C to 50°C.

[0010] Furthermore, the components in the device for measuring the resistance of a milliohm-level resistor are all connected via shielded leads.

[0011] Furthermore, the first current input port and the first voltage output port are specifically BNC type female sockets or N type female sockets.

[0012] The advantages of the present invention are as follows: compared with the prior art, the resistance value measuring device of milliohm resistor provided by the present invention ensures that the resistance value measuring device of milliohm resistor has excellent frequency response flatness and extremely small phase shift through the loop structure resistor with lower than standard temperature coefficient and lower than standard expansion coefficient, and because the loop structure resistor has lower than standard temperature coefficient and lower than standard expansion coefficient, it can achieve stable resistance characteristics in a wide current range. Moreover, a large AC and DC current of up to 10A / DC to 1kHz can be input to calibrate and measure the resistance value, thereby realizing accurate transmission of AC and DC resistance values ​​from mΩ.

[0013] The present invention also provides a resistance value measuring device, comprising: a resistance value measuring device for milliohm-level resistors and a resistance value measuring device for ohm-level to megohm-level resistors;

[0014] The resistance value measuring device of the ohm-level to megohm-level resistor comprises: a banana socket connector, a plurality of single-pole decimal switches, a plurality of AC and DC resistors corresponding one by one to the single-pole decimal switches, and a test port of the ohm-level to megohm-level resistor;

[0015] A plurality of the single-pole decimal switches are sequentially connected in series to form a single-pole decimal switch group, the output ends of the plurality of the single-pole decimal switches are respectively connected to the AC and DC resistors, the input ends of the two single-pole decimal switches at both ends of the single-pole decimal switch group are respectively connected to the two output ends of the banana socket connector; the input end of the banana socket connector is connected to the test port of the ohm-level to megohm-level resistor.

[0016] Furthermore, a plurality of the single-pole decimal switches are connected in series in sequence through shielded leads to form a single-pole decimal switch group, and the input ends of the two single-pole decimal switches at both ends of the single-pole decimal switch group are respectively connected to the two output ends of the banana socket connector through shielded leads.

[0017] Furthermore, the AC / DC resistor is a direct-insertion AC / DC resistor.

[0018] Further, it also includes: a fully shielded chassis;

[0019] The resistance measuring device for the milliohm-level resistor and the resistance measuring device for the ohm-level to megohm-level resistor are both arranged in the fully shielded chassis.

[0020] The advantages of the present invention are as follows: compared with the prior art, the resistance value measuring device provided by the embodiment of the present invention adopts a resistance value measuring device for milliohm-level resistors and a resistance value measuring device for ohm-level to megohm-level resistors, thereby realizing accurate transmission of AC and DC resistance values ​​from milliohm to megohm levels. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a specific structural diagram of a resistance value measuring device of the present invention.

[0022] Figure numerals: 1. first radio frequency connector; 2. second radio frequency connector; 3. four-pole ten-position switch; 4. loop structure resistor; 5. banana socket connector; 6. single-pole ten-position switch; 7. AC and DC resistors. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0024] A resistance value measuring device for milliohm-level resistors, comprising: a first current input port, a first voltage output port, a first radio frequency connector 1, a second radio frequency connector 2, a four-pole ten-position switch 3, and a loop structure resistor 4 corresponding to the interface of the four-pole ten-position switch 3; wherein the first current input port and the first voltage output port are specifically BNC female sockets or N-type female sockets. The four-pole ten-position switch 3 is silver-plated with contacts, which has the characteristics of low contact resistance and low thermal potential. The loop structure resistor 4 uses a resistance wire material with a lower temperature coefficient and a lower expansion coefficient than the standard. In this embodiment, a manganese copper alloy (Cu-Mn alloy / Manganin) with a very low temperature coefficient and expansion coefficient or a nickel-chromium alloy (Ni-Cr alloy) represented by ISA alloy Evanohm R / ISAOHM) is selected in the resistance wire. In the temperature range of 20°C to 50°C, their temperature coefficient can be as low as 20ppm / °C, and their expansion coefficient can also be lower than 20ppm / °C.

[0025] In the present embodiment, the loop-type structure resistor belongs to a high-power low-distributed parameter AC resistor of the order of mΩ. A resistance wire / resistance element with a low temperature coefficient and a low expansion coefficient is uniformly welded on a substrate with a high frequency response, a low expansion coefficient and a low loss in a central symmetrical manner, and two current terminals and two voltage terminals are led out with four leads. The two current lead-out terminals are on one side of the substrate, and the two voltage lead-out terminals are on the other side of the substrate. In order to ensure good heat dissipation performance and low loss parameters, the high-power loop-type structure resistor adopts an open structure as a whole. In the manufacturing process of this configuration resistor, the resistance wire / AC resistance element is closely attached to a stable substrate and installed by welding. Subsequently, the resistor as a whole is subjected to high and low temperature treatment to release the stress caused by plastic deformation, and acrylic sealant is sprayed on the surface to make it have good long-term stability. Then it is only necessary to use resistance wires / AC resistance elements of different quantities and resistance values.

[0026] The first current input port is connected to the input end of the first RF connector 1, and the first voltage output port is connected to the output end of the second RF connector 2; the first end of the four-pole ten-position switch 3 and the second end of the four-pole ten-position switch 3 are connected to the output end of the first RF connector 1, the third end of the four-pole ten-position switch 3 and the fourth end of the four-pole ten-position switch 3 are connected to the input end of the first RF connector 1, and the four-layer interface of one gear of the four-pole ten-position switch 3 is respectively connected to the current high end of the loop structure resistor 4, the current low end of the loop structure resistor 4, the voltage high end of the loop structure resistor 4 and the voltage low end of the loop structure resistor 4.

[0027] Working principle:

[0028] The instrument under test outputs a test current signal (AC / DC), which flows into the first RF connector 1 through the first current input port, and then flows into the loop structure resistor 4 through the first end of the four-pole ten-position switch 3 and the second end of the four-pole ten-position switch 3 (that is, two of the four-pole ten-position switch). The voltage signal generated on the loop resistor is sent to the second RF connector 2 through the third end of the four-pole ten-position switch 3 and the fourth end of the four-pole ten-position switch 3. The voltage signal is returned to the instrument under test through the second RF connector 2 through the first voltage output port. The current-voltage method of the instrument under test can measure the resistance value of the mΩ resistor, and its deviation can be obtained by comparing it with the standard value of the resistance box.

[0029] It can be seen that the loop structure resistor 4 with lower temperature coefficient and lower expansion coefficient than the standard ensures that the resistance value measuring device of milliohm resistance has excellent frequency response flatness and extremely small phase shift, and because the loop structure resistor 4 has lower temperature coefficient and lower expansion coefficient than the standard, it can achieve stable resistance characteristics in a wide current range. Moreover, a large AC and DC current of up to 10A / DC to 1kHz can be input to calibrate and measure the resistance value, thereby realizing accurate transmission of AC and DC resistance values ​​from mΩ.

[0030] Furthermore, the loop structure resistor 4 is a central symmetrical loop structure resistor 4. In this embodiment, the shielded lead wire is a single-strand coaxial braided copper wire aluminum foil shielded copper core wire.

[0031] Specifically, this central symmetrical loop structure can minimize the influence of the magnetic field between each resistance wire / AC resistance element in the resistor and the external magnetic field. Furthermore, the components in the resistance value measurement device of the milliohm resistor are all connected by shielded leads.

[0032] Specifically, since the components in the resistance measuring device for milliohm resistors are connected via shielded leads, the resistance measuring device for milliohm resistors has a better shielding effect during the measurement process.

[0033] The present invention also provides a resistance value measuring device, comprising: a resistance value measuring device for milliohm-level resistors and a resistance value measuring device for ohm-level to megohm-level resistors.

[0034] The resistance measuring device for the ohm-to-megaohm resistor comprises: a banana socket connector 5, a plurality of single-pole decimal switches 6, a plurality of AC / DC resistors 7 corresponding to the single-pole decimal switches 6, and a test port for the ohm-to-megaohm resistor; wherein the AC / DC resistor 7 is a plug-in AC / DC resistor 7. In this embodiment, the plug-in AC / DC resistor 7 is a precision alloy foil non-inductive AC / DC two-wire resistor, which is made of alloy resistance foil with a low temperature coefficient and is etched by an etching machine, and two pins are led out and then encapsulated with epoxy resin. The single-pole decimal switches 6 are all silver-plated contacts, which have the characteristics of low contact resistance and low thermal potential. The banana socket connector 5 is a copper gold-plated low thermal potential socket.

[0035] A plurality of the single-pole decimal switches 6 are connected in series in sequence to form a single-pole decimal switch group 6, the output ends of the plurality of the single-pole decimal switches 6 are respectively connected to the AC / DC resistors 7, the input ends of the two single-pole decimal switches 6 at both ends of the single-pole decimal switch group 6 are respectively connected to the two output ends of the banana socket connector 5; the input end of the banana socket connector 5 is connected to the test port of the ohm-level to megohm-level resistor.

[0036] In this embodiment, the resistance measuring device for ohm-level to megohm-level resistance, the AC and DC resistors 7 are respectively installed on the single-pole decimal switches 6. Multiple single-pole decimal switches 6 are installed and fixed on the front panel of the resistance box, and are connected in series with each other using the shielded lead wires, and the leads at both ends are respectively welded on two banana sockets. The banana socket is installed on the front panel and is a test port for the resistance range from Ω to MΩ.

[0037] Furthermore, a plurality of the single-pole decimal switches 6 are connected in series in sequence through shielded leads to form a single-pole decimal switch 6 group, and the input ends of the two single-pole decimal switches 6 at both ends of the single-pole decimal switch 6 group are respectively connected to the two output ends of the banana socket connector 5 through shielded leads.

[0038] Further, it also includes: a fully shielded chassis;

[0039] The resistance measuring device for the milliohm-level resistor and the resistance measuring device for the ohm-level to megohm-level resistor are both arranged in the fully shielded chassis.

[0040] Furthermore, the device also includes: a bracket; the bracket is mainly composed of cascaded metal pillars, and the connection method is threaded connection. The two ends of the metal pillars are male threads at one end and female threads at the other end, and every four pillars fix the four corners of a central loop structure resistor 4 substrate. Each resistor substrate is a layer, and the resistor box has multiple layers of resistors stacked by cascading pillars inside, and is installed behind the single-layer decimal switch connected in series, making full use of the three-dimensional space of the resistor box, thereby compressing the volume of the resistor box, reducing the volume of the resistor value measuring device, and ensuring the portability of the resistor value measuring device.

[0041] In this embodiment, the lead shielding layer is at the same potential as the metal outer shell of the chassis, the switch shaft, the switch metal back plate, and the metal structure bracket. The chassis dimensions of the resistance value measuring device are less than 500mm (width) × 126mm (height) × 145mm (depth), and the weight does not exceed 5.2kg, ensuring the portability of the resistance value measuring device.

[0042] In summary, the resistance value measuring device provided by the present invention uses a resistance value measuring device for milliohm-level resistors and a resistance value measuring device for ohm-level to megohm-level resistors, thereby achieving accurate transmission of AC and DC resistance values ​​from mΩ to MΩ.

[0043] For those skilled in the art, various other equivalent changes and modifications can be made according to the above technical solutions and concepts, and all of these changes and modifications should fall within the protection scope of the claims of the present invention.

Claims

1. A resistance measuring device for milliohm resistors, characterized in that: include: A first current input port, a first voltage output port, a first radio frequency connector, a second radio frequency connector, a four-pole ten-position switch, and a loop structure resistor corresponding to the interface of the four-pole ten-position switch; The first current input port is connected to the input end of the first RF connector, and the first voltage output port is connected to the output end of the second RF connector; The first end of the four-pole ten-position switch and the second end of the four-pole ten-position switch are connected to the output end of the first RF connector, the third end of the four-pole ten-position switch and the fourth end of the four-pole ten-position switch are connected to the input end of the second RF connector, and the four-layer interface of one gear of the four-pole ten-position switch is connected to the current high end of the loop structure resistor, the current low end of the loop structure resistor, the voltage high end of the loop structure resistor, and the voltage low end of the loop structure resistor respectively; The loop structure resistor adopts a resistance wire material with a temperature coefficient of less than 50ppm / ℃ and an expansion coefficient of less than 30ppm / ℃ within a temperature range of 20℃ to 50℃; The loop structure resistor is evenly welded on the substrate in a centrally symmetrical manner, and four leads are used to lead out two current terminals and two voltage terminals. The two current lead-out terminals are on one side of the substrate, and the two voltage lead-out terminals are on the other side of the substrate.

2. The resistance measuring device of milliohm resistor according to claim 1, characterized in that: The components in the resistance value measuring device of the milliohm-level resistor are all connected through shielded leads.

3. The resistance value measuring device of milliohm resistor according to claim 1, characterized in that: The first current input port and the first voltage output port are specifically BNC type female sockets or N type female sockets.

4. A resistance value measuring device, characterized in that: A device for measuring the resistance of a milliohm resistor as claimed in any one of claims 1 to 3 and a device for measuring the resistance of a resistor ranging from ohm to megohm; The resistance value measuring device of the ohm-level to megohm-level resistor comprises: a banana socket connector, a plurality of single-pole decimal switches, a plurality of AC and DC resistors corresponding one by one to the single-pole decimal switches, and a test port of the ohm-level to megohm-level resistor; A plurality of the single-pole decimal switches are sequentially connected in series to form a single-pole decimal switch group, the output ends of the plurality of the single-pole decimal switches are respectively connected to the AC and DC resistors, the input ends of the two single-pole decimal switches at both ends of the single-pole decimal switch group are respectively connected to the two output ends of the banana socket connector; the input end of the banana socket connector is connected to the test port of the ohm-level to megohm-level resistor.

5. The resistance value measuring device according to claim 4, characterized in that: A plurality of the single-pole decimal switches are connected in series in sequence through shielded leads to form a single-pole decimal switch group, and the input ends of the two single-pole decimal switches at both ends of the single-pole decimal switch group are respectively connected to the two output ends of the banana socket connector through shielded leads.

6. The resistance value measuring device according to claim 4, characterized in that: The AC / DC resistor is a direct-insertion AC / DC resistor.

7. The resistance value measuring device according to claim 4, characterized in that: Also includes: Fully shielded chassis; The resistance measuring device for the milliohm-level resistor and the resistance measuring device for the ohm-level to megohm-level resistor are both arranged in the fully shielded chassis.

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