The stability and accuracy of temperature sensors, as key components in modern electronic measurement and control systems, are crucial for the operation of the entire system. And resistance measurement, as an important means of evaluating the performance of temperature sensors, cannot be ignored. This article will delve into the resistance measurement methods and related principles of temperature sensors.
Classification and principle of temperature sensors
Temperature sensors can be classified into various types based on their working principles and materials, among which common ones include thermocouples, thermistors, thermistors, and infrared temperature sensors.
Thermocouple: measures temperature based on the relationship between the thermoelectric potential generated in a closed circuit composed of two different metals and temperature. For example, a K-type thermocouple generates a thermoelectric potential of approximately 20mV when measuring 500 ℃.
Thermistor: Using the characteristic of the resistance value of metals or semiconductors changing with temperature to measure temperature. For example, the resistance value of PT100 thermistor is 100 Ω at 0 ℃, and for every 1 ℃ increase in temperature, the resistance value increases by about 0.385 Ω.
Thermistor: Its resistance value is extremely sensitive to temperature changes and is usually divided into two types: positive temperature coefficient and negative temperature coefficient. Negative temperature coefficient thermistors experience a rapid decrease in resistance as the temperature rises.
Infrared temperature sensor: measures temperature by receiving infrared radiation energy emitted by an object, without the need to touch the object being measured. In industrial production, infrared temperature sensors can quickly measure the surface temperature of high-temperature objects.
Methods and Tools for Resistance Measurement
The resistance measurement of temperature sensors is mainly achieved through multimeters, thermocouple instruments, etc.
Multimeter: When using, first adjust to the resistance measurement mode, connect the positive and negative terminals of the sensor, and directly read the normal resistance value. For thermistors, they need to be heated before measurement. It should be noted that the rated resistance and temperature range of the sensor should be confirmed in advance to ensure that there is no additional resistance or line interference when measuring with a multimeter. When pursuing high precision, advanced instruments such as electric bridges can be used.
Thermocouple instrument: By measuring the temperature difference and potential difference, the resistance value can be read after connection. Heating is also required to measure the thermistor.
Specific steps and precautions for resistance measurement
1. Choose the appropriate measuring tool: Select the appropriate measuring tool based on the type of sensor, such as a multimeter or thermocouple instrument.
2. Connect the sensor: Ensure that the sensor is correctly connected to the measuring tool to avoid additional resistance or line interference.
3. Measurement and recording: Conduct resistance measurements and record the data. For thermistors, multiple measurements should be taken at different temperatures to evaluate their resistance characteristics as a function of temperature.
4. Data analysis: Compare the measurement results with the sensor specifications or relevant parameter tables to evaluate the performance of the sensor. If there is a significant deviation
between the measured value and the actual temperature value, it indicates that the temperature sensor may be damaged and needs to be replaced.
Advanced methods for resistance measurement
In addition to using multimeters and thermocouple instruments, more advanced methods such as the bridge method can also be used for resistance measurement. The bridge method constructs a balanced bridge and uses the proportional relationship of resistance values for measurement, which has high accuracy and stability. However, it should be noted that the bridge method requires professional equipment and operational skills, and the cost is relatively high.
conclusion
The resistance measurement of temperature sensors is an important means of evaluating their performance. By selecting appropriate measurement tools, following correct measurement steps and precautions, the accuracy and reliability of measurement results can be ensured. With the development and deepening of technology and applications, resistance measurement methods are constantly improving and innovating, providing a more comprehensive and accurate means for the performance evaluation of temperature sensors.
In short, the accuracy and reliability of temperature sensor resistance measurement are crucial for the operation of the entire system. Only by deeply understanding the principles, classifications, and measurement methods of temperature sensors can they be better applied in practical engineering and provide strong support for the development of modern electronic measurement and control systems.
Source: Sensor Expert Network. If there is any infringement, please contact us for deletion.