Method for measuring temperature coefficient of chip resistor

Abstract

The invention discloses a method for measuring the temperature coefficient of a chip resistor, and the method is characterized in that the method comprises the following steps: S1, selecting a PCB with the use temperature of-80 DEG C to 200 DEG C as a carrier of a measured element, enabling the carrier to be provided with a sample fixing region, and enabling the two sides of the sample fixing region to be provided with pin regions communicated with the sample fixing region; s2, fixing a measured element on a sample fixing area of the PCB through a sample clamp, and connecting the measured element with a resistance measuring instrument through a pin area; s3, putting the carrier fixed with the measured element into a high and low temperature environment measurement box capable of realizing a temperature range from-60 DEG C to 150 DEG C; and S4, controlling the resistance measuring instrument and the high and low temperature ring measuring box through the PC control unit to realize resistance measurement at the room temperature of 25 DEG C, the low temperature of-55 DEG C and the high temperature of 125 DEG C, and then calculating a corresponding low temperature coefficient and a corresponding high temperature coefficient. The method has the characteristics of high measurement efficiency, high stability and high accuracy.

Description

Technical Field

[0001] The invention relates to the field of resistance temperature coefficient measurement, and in particular to a method for measuring the temperature coefficient of a chip resistor. Background Art

[0002] At present, the temperature coefficient of chip resistors in the market is tested by integrating the measured component into a high and low temperature resistant box, and then placing the box into a high and low temperature ring test box. The advantage of this method is that it is highly integrated, and only a few simple wires are needed to connect to the control unit. However, in order to protect the measured components in the box from the influence of high and low temperatures, the outer layer of the box is usually wrapped with several layers of thermal insulation materials. These thermal insulation materials have low thermal conductivity and absorb and release heat very slowly, which results in a temperature difference of 10 to 40°C between the surface temperature of the box and the ambient temperature when the ambient temperature is already at the target test temperature. This results in the measured component being affected by the box temperature in addition to the ambient temperature, which greatly reduces the accuracy, stability and consistency of the temperature coefficient measurement; in addition, due to the use of a box with low thermal conductivity, it takes longer for the high and low temperature box to reach the target temperature, which reduces the test efficiency and causes energy waste. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a method for measuring the temperature coefficient of a chip resistor, which has the characteristics of high measurement efficiency, high stability and high accuracy.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A method for measuring the temperature coefficient of a chip resistor, characterized in that it comprises the following steps:

[0006] S1. A PCB board with a use temperature of -80°C to 200°C is selected as a carrier of the component under test, and a sample fixing area is provided on the carrier, and pin areas connected to the sample fixing area are provided on both sides of the sample fixing area;

[0007] S2, the component under test is fixed on the sample fixing area of ​​the PCB board through the sample fixture, and is connected to a resistance measuring instrument through the pin area;

[0008] S3, placing the carrier with the tested component fixed thereon into a high and low temperature test chamber capable of achieving a temperature range of -80°C to 200°C;

[0009] S4. The resistance measuring instrument and the high and low temperature environment test box are controlled by the PC control unit to achieve resistance measurement at room temperature 25°C, low temperature -55°C and high temperature 125°C, and then the corresponding low temperature temperature coefficient and high temperature temperature coefficient are calculated.

[0010] Preferably, the pin area has a plurality of test line solder joints, and a hollow anti-interference insulating section is provided in the pin area to separate adjacent test line solder joints.

[0011] Preferably, the test wire solder joint is connected to the resistance measuring instrument via a four-wire connection.

[0012] Preferably, the sample fixture is a gold finger slot, and the component to be tested is fixed on the gold finger slot through a gold finger carrier.

[0013] Preferably, a plurality of sample fixing areas are provided on the carrier.

[0014] The advantages of the present invention are:

[0015] 1. The measured components are no longer affected by the temperature of the box with insulation layer, which greatly improves the accuracy, stability and consistency of temperature coefficient measurement, improves test efficiency and reduces energy loss;

[0016] 2. On the PCB carrier, a hollow partition setting is introduced to improve the accuracy of resistance measurement above 10Mohm;

[0017] 3. The test line solder joint introduces a four-wire connection design to shorten the distance to the measured component, reduce the internal resistance, and improve the measurement accuracy of resistance values ​​below 10ohms. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A module diagram of the method for measuring the temperature coefficient of a chip resistor provided in this embodiment;

[0019] Figure 2 A schematic diagram of the carrier provided in this embodiment. DETAILED DESCRIPTION

[0020] Combination Figure 1 to Figure 2 The method for measuring the temperature coefficient of chip resistor of the present invention is further described.

[0021] A method for measuring the temperature coefficient of a chip resistor, characterized in that it comprises the following steps:

[0022] S1. A PCB board with a use temperature of -80°C to 200°C is selected as a carrier 4 of the measured component, i.e., a resistor. The carrier 4 has a sample fixing area 41, and pin areas 42 connected to the sample fixing area 41 are provided on both sides of the sample fixing area 41.

[0023] PCB boards are easy to process and shape, have strong weather resistance, and low thermal capacity, and will not affect the temperature of the components under test, thereby improving the accuracy, consistency, and efficiency of the test.

[0024] S2. The component under test is fixed on the sample fixing area 41 of the PCB board through a sample fixture, and is connected to the resistance measuring instrument 2 through the pin area 42.

[0025] S3, placing the carrier 4 with the tested element fixed thereon into a high and low temperature environment test box 1 which can achieve a temperature range of -80°C to 200°C;

[0026] S4, the resistance measuring instrument 2 and the high and low temperature ring measuring box 1 are controlled by the PC control unit 3 to measure the resistance values ​​at room temperature 25°C, low temperature -55°C and high temperature 125°C, and then the corresponding low temperature temperature coefficient and high temperature temperature coefficient are calculated. During the measurement, the resistance measuring instrument 2 is located outside the high and low temperature ring measuring box 1.

[0027] In the above steps, the preferred operating temperature of the PCB board is -60°C to 150°C.

[0028] The sample fixture is a gold finger slot, which is welded on the sample fixing area 41. The component under test is fixed on the gold finger slot through a gold finger carrier. That is, the component under test is fixed to the carrier with gold fingers, and then the carrier is inserted into the gold finger slot through the gold fingers on it, so that the component under test, the pin area 42 and the resistance measuring instrument 2 are turned on.

[0029] In the structure of the PCB carrier 4, the pin area 42 is composed of a plurality of test line solder joints arranged along the length direction of the gold finger slot. In the present embodiment, each test line solder joint is composed of two pin pins 4211. The pin area 42 is provided with a hollow anti-interference insulating section 422 that separates adjacent test line solder joints. The gold finger carrier has a plurality of mounting positions for the components under test, and there is no conduction between the mounting positions. A plurality of test line solder joints 421 correspond to and conduct with a plurality of mounting positions one by one, so as to realize the simultaneous online measurement of a plurality of components under test. The hollow anti-interference insulating section 422 eliminates the influence of the parallel conductive path on the resistance above 10Mohm due to the reduced electrical insulation of the PCB board during the 125°C high temperature TCR test, thereby greatly improving the measurement accuracy of the high temperature TCR of resistors above 10Mohm.

[0030] Each test line solder joint 421 is connected to the resistance measuring instrument 2 via a four-wire connection. The introduction of a four-wire design to each test line solder joint 421 can shorten the distance from the test line to the component under test, reduce internal resistance, and improve the measurement accuracy of resistance values ​​below 10 ohms.

[0031] There are multiple sample fixing areas 41 on the carrier 4, so that multiple samples can be measured online at the same time.

[0032] In this embodiment, the calculation formula of the temperature coefficient of the measured element is:

[0033] The low temperature coefficient of temperature (CTCR) test temperature range is -55℃~25℃; the high temperature coefficient of temperature (HTCR) test temperature range is 25℃~125℃;

[0034]

[0035] Among them, t1 is the reference temperature, that is, when the room temperature is 25℃, t2 is the test temperature, that is, when the temperature is between -55 and +125, R1 is the resistance at the reference temperature, and R2 is the resistance at the test temperature.

[0036] Example 1: The following Examples 1 to 3 are TCR test results of conventional resistors using this implementation.

[0037] Example 1, TCR test of a 10 ohm resistor in a high temperature environment of 125°C:

[0038]

[0039] The TCR test results of 10ohm resistor in -55℃ low temperature environment:

[0040] Example 2, test results of TCR of a 10Kohm resistor in a high temperature environment of 125°C:

[0041]

[0042] The TCR of a 10Kohm resistor is tested in a -55℃ low temperature environment:

[0043]

[0044] Example 3, test results of TCR of 1Mohm resistor in a high temperature environment of 125°C:

[0045]

[0046] The TCR of a 1Mohm resistor is tested in a -55°C low temperature environment:

[0047]

[0048] The following comparative example 1 is a test result of the TCR of a 10Kohm resistor using a traditional method: The test result of the TCR of a 10Kohm resistor in a high temperature environment of 125°C:

[0049]

[0050] The TCR of a 10Kohm resistor is tested in a -55℃ low temperature environment:

[0051]

[0052] By comparing Example 2 in Example 1 with Comparative Example 1, it can be seen that when the TCR of the resistor is tested in high temperature and low temperature environments, the fluctuation amplitude of the TCR in the comparative example is significantly greater than the fluctuation amplitude of the TCR in Example 2. Therefore, it can be concluded that the measured component is not affected by the temperature of the box with the insulation layer, which greatly improves the stability of the temperature coefficient measurement.

[0053] In Example 1, the difference between the mean HTCR and the mean CTCR is 85; in Example 2, the difference between the mean HTCR and the mean CTCR is 48; in Example 3, the difference between the mean HTCR and the mean CTCR is 70; in Comparative Example 1, the difference between the mean HTCR and the mean CTCR is 17. It can be seen that the difference between HTCR and CTCR in Comparative Example 1 is significantly smaller than the difference between HTCR and CTCR in Examples 1 to 3. The small difference indicates that the measured values ​​of HTCR and CTCR are both small, and the temperature error during the test is large, which further indicates that the test results using this solution are more accurate.

[0054] Example 2: Comparison of TCR accuracy of hollow anti-interference insulation section 422 on resistors with resistance values ​​above 10Mohm.

[0055]

[0056] In combination with Example 2, it can be concluded that introducing a physical partition in the pin area 42 of the PCB board, that is, providing a hollow anti-interference insulating section 422, can improve the stability and accuracy of the measurement of resistance values ​​above 10Mohm.

[0057] Unless otherwise specified, in the present invention, the terms "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings, which 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 operate in a specific orientation. Therefore, the terms describing the orientation or positional relationship in the present invention are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood in conjunction with the accompanying drawings and according to specific circumstances.

[0058] Unless otherwise clearly specified and limited, in the present invention, the terms "disposed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for measuring the temperature coefficient of a chip resistor, characterized in that: The following steps are involved: S1. A PCB board with a use temperature of -80°C to 200°C is selected as a carrier of the component under test, and a sample fixing area is provided on the carrier, and pin areas connected to the sample fixing area are provided on both sides of the sample fixing area; S2, the component under test is fixed on the sample fixing area of ​​the PCB board through the sample fixture, and is connected to a resistance measuring instrument through the pin area; S3, placing the carrier with the tested component fixed thereon into a high and low temperature test chamber capable of achieving a temperature range of -80°C to 20°C; S4. The resistance measuring instrument and the high and low temperature environment test box are controlled by the PC control unit to achieve resistance measurement at room temperature 25°C, low temperature -55°C and high temperature 125°C, and then the corresponding low temperature temperature coefficient and high temperature temperature coefficient are calculated.

2. The method for measuring the temperature coefficient of chip resistor according to claim 1, characterized in that: The pin area has a plurality of test line welding points, and a hollow anti-interference insulating section is arranged in the pin area to separate adjacent test line welding points.

3. The method for measuring the temperature coefficient of chip resistor according to claim 2, characterized in that: The test lead solder joints are connected to the resistance meter via a four-wire connection.

4. The method for measuring the temperature coefficient of chip resistor according to claim 3, characterized in that: The sample fixture is a gold finger slot, and the component under test is fixed on the gold finger slot through a gold finger carrier.

5. The method for measuring the temperature coefficient of chip resistor according to claim 1, characterized in that: There are multiple sample fixing areas on the carrier.

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