How to choose suitable materials for different thermal resistors

With the continuous advancement of science and technology in my country and the rapid progress of various industries, the requirements for the tools used are becoming increasingly stringent. As we all know, RTDs are a commonly used temperature detector, boasting high measurement accuracy and stable performance. They are mostly made of pure metals. Currently, platinum and copper are the most commonly used, but materials such as tin, nickel, manganese, and rhodium have also been developed. They are not only widely used in industrial temperature measurement but also serve as standard reference instruments. However, different RTD materials have different criteria for selecting their materials. Below, we will explain how to correctly select the right materials for different RTDs.

1. The RTD material should have a nearly linear relationship with temperature.

2. The RTD should have a high resistivity. A higher resistivity reduces the RTD's volume, heat capacity, and thermal inertia, resulting in a faster response to temperature changes.

3. The RTD material should have good reproducibility to ensure accurate application.

4. The RTD should be within the temperature measurement range and have stable chemical and physical properties.

5. The temperature coefficient of the thermal resistor should be as large as possible. Since the temperature coefficient of resistance is defined as the relative change in resistance for every 1 Kelvin increase in temperature, the larger the temperature coefficient of resistance, the higher the sensitivity of the thermometer and the more accurate the measurement results.