In industrial temperature measuring equipment, we often encounter thermal resistance and thermocouple. Many people will think that they are two ways of calling something. In fact, they are two very different things.

They are connected to thermometers, but their principles and ranges are different. First of all, thermal resistance, which is generally used for low temperature measurement, is based on the fact that the resistance value of metal conductors increases with the increase of temperature. Thermal resistors are mostly made of pure metal materials, and platinum and copper are the most widely used materials. In addition, nickel, manganese and rhodium have been used to make thermal resistors. Pt100, Pt10, Cu50, Cu100, PT1000 platinum thermal resistors are generally used for industrial thermal resistors. The temperature measurement range of Pt100, Pt10, Cu100 and PT1000 platinum thermal resistors is generally 200-800 degrees below zero, and copper thermal resistors are 40-140 degrees below zero.

Thermocouples are generally used in the measurement of medium and high temperature. The working principle of thermocouples is based on seeback effect, that is, the two ends of conductors with two different components are connected into a loop. If the temperature of the two ends is different, the physical phenomenon of thermal current will be generated in the loop. Thermocouples have a wide range of measurements, commonly used are platinum-rhodium (scale S, measurement range 0-1300 degrees), nickel-chromium-nickel-silicon (scale K, measurement range 0-900 degrees), nickel-chromium-constantan (scale E, measurement range 0-600 degrees), platinum-rhodium 30-platinum-rhodium 6 (scale B, measurement range 0-1600 degrees). Thermocouples are more expensive than thermal resistors because they are made of precious metals.