Detailed Explanation of the Working Principle of PT100 Thermal Resistance: From Basic Principles to Practical Applications

1.Introduction to PT100 Thermal Resistance

PT100 is a Platinum resistance Temperature Sensor. The "PT" in its name stands for platinum, and "100" indicates that the resistance value is 100Ω at 0°C. It belongs to a type of RTD (Resistance Temperature Detector), featuring good linearity, high stability, and a wide measurement range (-200°C to +850°C), and is one of the core components in the field of industrial temperature measurement.

2.Working Principle of PT100 Thermal Resistance

The core principle of PT100 is based on the characteristic that the resistance of metallic platinum changes with temperature, and the relationship between its resistance value and temperature conforms to the IEC 60751 international standard.

3.Structure and Types of PT100

PT100 can be classified by packaging method as:

Thin-film PT100: Utilizing platinum thin-film deposition technology, it features a compact size and fast response, making it suitable for medical, laboratory and other scenarios.

Wound PT100: Platinum wire is wound on a ceramic frame, featuring high stability and suitability for industrial high-temperature environments.

Armored PT100: Metal casing protection, anti-vibration and corrosion-resistant, suitable for harsh working conditions.

4.Measurement Circuits of PT100 (Two-wire, three-wire, four-wire)

Since the resistance of the wire can affect the measurement accuracy, PT100 usually adopts three-wire or four-wire connection methods:

Two-wire system: Simple but with large errors, it is suitable for short-distance measurement.

Three-wire system (the most commonly used) : By compensating the resistance of the compensating wire, the accuracy is improved.

Four-wire system: Highest precision, suitable for laboratory-level measurement.

5.Typical application scenarios of PT100

Industrial automation: PLC temperature control, boiler monitoring, HVAC systems.

Medical equipment: temperature monitoring, PCR instrument, blood analyzer.

Food industry: Cold chain logistics, temperature monitoring of baking equipment.

Scientific research experiments: High-precision constant temperature chamber, environmental test chamber.

6.Selection and Maintenance Precautions for PT100

Key points for selection:

Measurement range (-200°C to 850°C)

Accuracy grade (Grade A ±0.15°C, Grade B ±0.3°C)

Packaging method (film type/wound type/armored)

Maintenance suggestions:

Avoid mechanical vibration and chemical corrosion

Regular calibration is carried out to ensure accuracy

PT100 thermal resistance has become a core sensor in the field of temperature measurement due to its advantages such as high precision, strong stability and good linearity. This article elaborately analyzes the working principle of PT100, the resistance-temperature relationship, the measurement circuit and typical applications, helping readers fully master its technical key points. In fields such as industrial automation, medical equipment, and scientific research experiments, the correct selection and application of PT100 can significantly enhance the reliability of temperature measurement systems.