Three-electrode precision resistance and test assembly

Abstract

The utility model discloses a three electrode precision resistance, including resistance element, with the first end electrode of resistance element one end connection, with the second end electrode of resistance element other end connection, be located between the first end electrode and the second end electrode and with the intermediate electrode of resistance element surface connection, can measure the first resistance value between first end electrode and intermediate electrode, the second resistance value between intermediate electrode and second end electrode and the third resistance value between first end electrode and second end electrode, the utility model discloses still provided the test subassembly of containing this three electrode precision resistance.

Description

Technical Field

[0001] This utility model relates to the field of precision resistor technology. Background Technology

[0002] Precision resistors are key components in various high-precision electronic devices, measuring instruments, sensors, and signal processing systems. The stability and accuracy of their resistance directly determine the performance of the entire system. As electronic products become increasingly miniaturized and denser, the size of surface-mount precision resistors is decreasing daily. However, problems arise in practical applications with small-sized resistors, including:

[0003] Influence of soldering stress: During reflow soldering or wave soldering, uneven cooling of the solder and mismatch in the coefficient of thermal expansion (CTE) between the PCB (printed circuit board) and the resistor material can generate mechanical stress within the resistor. This stress alters the crystal structure of the resistor material, causing an irreversible shift in its resistance value.

[0004] Thermoelectric electromotive force effect: When current flows through the interface between different materials (such as resistor and electrode, electrode and solder, solder and PCB copper foil), a thermoelectric electromotive force is generated due to the material difference, forming an additional error voltage signal. This error is particularly significant when measuring minute voltage signals (ultra-low resistance products).

[0005] Contact resistance and thermal noise: There is contact resistance at the contact point between the electrode and the external circuit, and its instability can introduce measurement errors. At the same time, the current density of small resistors may be higher, resulting in more significant thermal noise.

[0006] Traditional two-terminal resistors can only provide a total resistance signal and cannot distinguish or eliminate errors introduced by external factors. Therefore, a new technical solution is needed to solve these problems. Utility Model Content

[0007] To address the above problems, the purpose of this invention is to provide a three-electrode precision resistor with a simple structure that can monitor resistance signals at multiple locations.

[0008] Another objective of this invention is to provide a testing component for monitoring the resistance value of a three-electrode precision resistor and compensating for resistance errors.

[0009] To achieve the above-mentioned objectives, the three-electrode precision resistor of this invention can adopt the following technical solution:

[0010] A three-electrode precision resistor includes a resistive element, a first end electrode connected to one end of the resistive element, a second end electrode connected to the other end of the resistive element, and an intermediate electrode located between the first end electrode and the second end electrode and connected to the surface of the resistive element.

[0011] Furthermore, an insulating protective layer covering the surface of the resistive element is provided between the intermediate electrode and the first end electrode, and between the intermediate electrode and the second end electrode.

[0012] Furthermore, the intermediate electrode is connected to the middle position of the resistive element, and the distance from the intermediate electrode to the first end electrode is equal to the distance from the intermediate electrode to the second end electrode.

[0013] Furthermore, a resistor carrier is provided, which covers the side of the resistor element that faces away from the middle electrode. The resistor carrier is an insulator.

[0014] Furthermore, the first end electrode, the second end electrode, and the intermediate electrode each include three metal plating layers, which are, from the inside out, a tin plating layer, a nickel plating layer, and a copper plating layer.

[0015] Beneficial effects: This three-electrode precision resistor, by setting three electrodes, can measure the total resistance signal and the resistance signals of two local positions by connecting the electrodes in pairs, which can more clearly confirm the resistance error.

[0016] The testing component provided by this utility model adopts the following technical solution:

[0017] A test assembly including the three-electrode precision resistor further includes a first current probe, a second current probe, a first voltage probe, a second voltage probe, and a third voltage probe; wherein the first current probe and the first voltage probe are both connected to a first end electrode, the second current probe and the second voltage probe are both connected to a second end electrode, and the third voltage probe is connected to an intermediate electrode.

[0018] Furthermore, it also includes a power supply and a voltage measuring device, wherein the power supply is connected to the first current probe and the second current probe to energize, and the voltage measuring device is connected to the first voltage probe and the second voltage probe, the first voltage probe and the third voltage probe and / or the second voltage probe and the third voltage probe.

[0019] Beneficial effects: Compared with the prior art, the test component of this utility model can obtain stable resistance value results, and can compensate for resistance error by controlling the on / off state of the MOS circuit or the increase / decrease of the current to keep the voltage information on the three resistors at the set value. Attached Figure Description

[0020] Figure 1 This is a bottom view of the three-electrode precision resistor in this utility model;

[0021] Figure 2 This is a cross-sectional view of the three-electrode precision resistor in this utility model;

[0022] Figure 3 This is the wiring diagram for three-electrode precision resistance testing;

[0023] Figure 4 This is a schematic diagram of the test component in this utility model. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] Example 1

[0026] Please combine Figure 1 and Figure 2 As shown, this embodiment discloses a three-electrode precision resistor, including a resistor carrier 1, a resistor element 2, a first end electrode 3, an intermediate electrode 4, a second end electrode 5, and an insulating protective layer 6 (7).

[0027] An insulating protective layer covers the surface of the resistive element 2 between the intermediate electrode 4 and the first end electrode 3, and between the intermediate electrode 4 and the second end electrode 5. The intermediate electrode 4 is connected at the middle position of the resistive element 2, and the distance from the intermediate electrode 4 to the first end electrode 3 is equal to the distance from the intermediate electrode 4 to the second end electrode 5, but this distance is not less than 0.2 mm.

[0028] The first end electrode 3, the intermediate electrode 4, and the second end electrode 5 each include three metal plating layers. From the inside out, the first end electrode 3 consists of a first copper plating layer 31, a first nickel plating layer 32, and a first tin plating layer 33. From the inside out, the intermediate electrode 4 consists of a second copper plating layer 41, a second nickel plating layer 42, and a second tin plating layer 43. From the inside out, the second end electrode 5 consists of a third copper plating layer 51, a third nickel plating layer 52, and a third tin plating layer 53.

[0029] Example 2

[0030] Please combine Figure 3 and Figure 4 As shown, this embodiment is a test assembly. In addition to the three-electrode precision resistor of Embodiment 1, the test assembly also includes a first current probe 8, a second current probe 9, a first voltage probe 10, a second voltage probe 11, and a third voltage probe 12. The first current probe 8 and the first voltage probe 10 are both connected to the first terminal electrode 3, the second current probe 9 and the second voltage probe 11 are both connected to the second terminal electrode 5, and the third voltage probe 12 is connected to the intermediate electrode 4. It also includes a power supply (MOS) and an MCU. The power supply is connected to the first current probe 8 and the second current probe 9 to provide power, and the MCU is connected to the first voltage probe 10 and the second voltage probe 11, the first voltage probe 10 and the third voltage probe 12, and / or the second voltage probe 11 and the third voltage probe 12.

[0031] The test method using this test component is as follows: Measure the first resistance R1 between the first terminal electrode 3 and the intermediate electrode 4, the second resistance R2 between the intermediate electrode 4 and the second terminal electrode 5, and the third resistance R1 between the first terminal electrode 3 and the second terminal electrode 5, respectively. 总 Under constant current conditions, the resistance between each electrode is fed back to the MCU through a voltage signal. When the circuit fluctuates and the current in the circuit changes, the voltage of each resistor will change. At this time, the MCU issues a command to control the MOS circuit to turn it on or off or increase or decrease the current so that the voltage information on the three resistors is always kept at the set value.

[0032] The above measurement system can obtain stable resistance values, which can then be adjusted mechanically or by laser to meet design requirements. Further measurement requires repeated adjustments to balance R1, R2, and R... 总 All targets were met.

Claims

1. A three-electrode precision resistor, characterized in that: It includes a resistive element, a first end electrode connected to one end of the resistive element, a second end electrode connected to the other end of the resistive element, and an intermediate electrode located between the first end electrode and the second end electrode and connected to the surface of the resistive element.

2. The three-electrode precision resistor as described in claim 1, characterized in that, An insulating protective layer covering the surface of the resistive element is provided between the intermediate electrode and the first end electrode, and between the intermediate electrode and the second end electrode.

3. The three-electrode precision resistor as described in claim 1 or 2, characterized in that, The intermediate electrode is connected to the middle position of the resistive element, and the distance from the intermediate electrode to the first end electrode is equal to the distance from the intermediate electrode to the second end electrode.

4. The three-electrode precision resistor as described in claim 1, characterized in that, It also includes a resistor carrier that covers the side of the resistor element that faces away from the middle electrode. The resistor carrier is an insulator.

5. The three-electrode precision resistor as described in claim 1, characterized in that, The first end electrode, the second end electrode, and the intermediate electrode each include three metal plating layers, which are tin plating, nickel plating, and copper plating from the inside out.

6. A test assembly comprising a three-electrode precision resistor as described in any one of claims 1 to 5, characterized in that, It also includes a first current probe, a second current probe, a first voltage probe, a second voltage probe, and a third voltage probe; The first current probe and the first voltage probe are both connected to the first terminal electrode, the second current probe and the second voltage probe are both connected to the second terminal electrode, and the third voltage probe is connected to the intermediate electrode.

7. The test component as described in claim 6, characterized in that, It also includes a power supply and a voltage measuring device. The power supply is connected to the first current probe and the second current probe to energize them. The voltage measuring device is connected to the first voltage probe and the second voltage probe, the first voltage probe and the third voltage probe, and / or the second voltage probe and the third voltage probe.

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