The temperature coefficient (TCR) of a test resistor usually follows certain standards and methods. The following are the steps and key points obtained based on the search results:
1. Reference standards:
According to the GB/T 6148-2005 standard, this standard specifies the testing method for the temperature coefficient of resistance of precision resistance alloys, which is applicable for measurement in the temperature range of -65 ℃ to 250 ℃.
2. Testing scope:
Testing is typically conducted within a specific temperature range, such as -65 ℃ to 250 ℃, to cover the possible operating temperature range of the resistance alloy.
3. * * Sample Preparation * *:
The sample should be taken from the continuous length of the tested alloy, and its resistance value should meet the accuracy requirements for measurement. The minimum resistance of the sample shall not be less than 1 Ω.
4. Wiring terminals and wires:
When the resistance of the sample is less than or equal to 100 Ω, solder current and potential terminals at both ends of the sample. When the resistance of the sample is greater than 100 Ω, the single arm bridge method can be used, and a copper wire can be welded at each end of the sample as the terminal. The resistance of the wire should be minimized as much as possible to avoid affecting the measurement results.
5. Experimental environmental conditions:
The ambient temperature of the measuring instrument should be 20 ℃± 2 ℃, and the temperature change should be within 1 ℃. The relative humidity of the environment should not exceed 80%.
6. Test current:
The test current should not be too high to reduce the thermal effect of the sample current and ensure measurement accuracy. The load power of the sample during measurement shall not exceed 0.1W.
7. Measurement method:
The commonly used methods for resistance measurement are the electric bridge method and the potential difference meter method, and the electric bridge method is used as a substitute in arbitration. The testing program includes connecting the circuit, preheating with power, and ensuring that the device is in normal working condition. Immerse all samples in the tank solution, first measure the initial resistance value at 20 ℃, and then measure point by point from high temperature to low temperature. When the sample changes from one temperature to another, it must be held for 10 minutes after the resistance value of the sample stabilizes before measurement, and the temperature and corresponding resistance value should be recorded.
8. Data processing:
By measuring the relative change △ R of the resistance value relative to 20 ℃, the values of the primary and secondary resistance temperature coefficients a and β can be determined. The temperature coefficient of resistance can be calculated using a formula, which involves parameters such as resistance values at different temperatures, reference temperature, and test temperature.
9. Numerical rounding:
The calculated values of a and β are represented using scientific notation. The experimental data shall be rounded according to the provisions of GB/T 8170-1987.
Through the above steps, the temperature coefficient of resistance can be accurately tested, which is crucial for evaluating the performance changes of resistance at different temperatures.