The Pt100 temperature sensor is a common thermal resistance sensor that uses platinum (Pt) as the material of the sensor element. Pt100 represents a specific type of platinum thermal resistor, where 100 means that the resistance value of the platinum thermal resistor is 100 ohms at 0°C.

The principle of Pt100 temperature sensor is to utilize the linear relationship between platinum thermal resistance and temperature. As the temperature changes, the resistance value of the platinum thermal resistor will also change accordingly. According to international standards, the resistance of Pt100 temperature sensors has specific values at different temperatures. A common standard is IEC 60751, which specifies the resistance-temperature relationship for Pt100 temperature sensors.

Pt100 temperature sensors usually consist of platinum thermistor wire wound around a ceramic or glass chip and encapsulated in a protective case. They can directly contact the object being measured and calculate the temperature by measuring the resistance value of the platinum thermal resistor. Pt100 temperature sensor has the characteristics of high precision, stability and good linearity, and is widely used in industrial control, laboratory testing, temperature monitoring and other fields.

The output of a Pt100 temperature sensor is usually a resistance value, which requires a temperature measurement device or converter to convert the resistance value into a temperature value. Common conversion methods are to use lookup tables or interpolation calculations based on the resistance-temperature relationship of Pt100. Modern temperature measurement equipment usually has built-in Pt100 temperature sensor input and temperature conversion functions, making temperature measurement more convenient and accurate.

The accuracy of Pt100 temperature sensors can vary depending on build quality and application requirements. Generally speaking, the standard accuracy of Pt100 temperature sensors is Category A, B and Category ⅓B.

Category A: Within the temperature range -200°C to +650°C, the Pt100 temperature sensor of category A has an accuracy of ±(0.15+0.002|t|)°C, where |t| represents the absolute value of the temperature value, in units is degrees Celsius. Over this temperature range, the accuracy is ±0.15°C plus 0.2% of the temperature value.

Category B: Category B Pt100 temperature sensors have an accuracy of ±(0.3+0.005|t|)°C over the temperature range -200°C to +650°C. Category B accuracy is slightly lower than Category A, at ±0.3°C plus 0.5% of the temperature value.

Category ⅓B: Category ⅓B Pt100 temperature sensors have an accuracy of ±(0.1+0.003|t|)°C over the temperature range -200°C to +450°C. Category ⅓B has a relatively high accuracy of ±0.1°C plus 0.3% of the temperature value.