The test methods of resistance value mainly include resistor bridge method, voltammetry law method and current method. Resistor bridge method is the most commonly used method to measure high power resistance. The most basic bridge is the Wheatstone and Kelvin bridge method. The law of voltammetry is to use the law of steady-state circuit to measure the resistance value of the resistance, it can be used to measure large resistance. This is Texas-instrument-ISO7742qDqQ. For small resistance, you can use the current method, that is, the current method to measure resistance, you can measure the resistance value of small resistance, especially minimal resistance.
The test method of resistance value in the circuit includes: 1. Ohm's law; 2. bridge method; 3. comparative law; 4. frequency change; 5. Voltage drop method; 6. temperature compensation method; 7. two-point method; 8. overcurrent method; 9. resistance partial voltage method; 10. dynamic impedance measurement.
In addition, there are other ways to measure resistance, such as the voltage-current (V-I) ratio, the use of multiple components to measure resistance, the use of cross-bridge method to measure resistance, the use of constant voltage source probes to measure resistance, etc.
At the same time, the resistance value can also be measured by electronic measuring instruments, such as meter, multimeter, oscilloscope and digital multi-waveform oscilloscope, they have high sensitivity, high precision, easy to operate and so on.
In addition, microprocessors can be used to measure resistance values, which can provide higher accuracy and lower measurement error, making it a more ideal choice for measuring resistance values. In addition, optical and quantum effects can be used to measure resistance, which is the most accurate method, but also requires expensive instrumentation.
In practical applications, the measurement of resistance value is sometimes subject to some external interference, such as temperature change, the influence of external electromagnetic field, in this case, the measurement personnel need to take some special measures to reduce the interference, so as to ensure the accuracy of measurement.
Note the matters that need to pay attention to the measurement of resistance value and resistance rating, for low resistance of the resistance rating is lower, the precision of the resistance is lower, so in the selection of resistance should pay attention to choose a higher rating resistance, to ensure the accuracy of measurement. In addition, attention should be paid to avoid the interference of external magnetic field during measurement to ensure the accuracy of measurement.
In the use of electronic instruments for measurement, measurement personnel should also pay attention to the use of the instrument, to ensure the accuracy of the instrument, as well as the setting of instrument parameters and measurement signal processing. In addition, the measurement personnel should also pay attention to control the output voltage of the power supply to ensure the accuracy and reliability of the resistance value.
In addition, when measuring the resistance value, the measurement personnel should also pay attention to maintaining the safety of the resistor, and ensure that the quality of the resistor used meets a certain standard, so as to avoid the problem of inaccurate measurement. Therefore, in practice, surveyors should operate in accordance with relevant safety regulations to ensure measurement accuracy and safety.
In summary, the measurement of resistance value needs certain technical skills. In the measurement, we should pay attention to the rating and stability of the resistance, to ensure the accuracy of the measuring instrument, ensure the output voltage of the power supply, reduce the external electromagnetic interference, and pay attention to safety measures to ensure the accuracy and reliability of the measurement.