What is the thermometer of resistance?

Thermometer of resistance, also known as the thermal device for resistance (RTD), is specifically for metals that pushes the electricity with metal and assesses its temperature on the basis of resistance. Its chemical inert and other factors mean that platinum is the most common metal used in the resistance thermometer. There are different types of RTDs that are assessed mostly about how many wires are included in the device; More wires means better accuracy. Although it is a reliable device, RTD is not used at temperatures above 1,112 ° Fahrenheit (600 ° Celsius) or below -518 ° F (-270 ° C) for complications. When the metal heats up, its resistance increases; If RTD encounters higher resistance, the metal is very hot. By correlation of these two factors, RTD can arrive at a precise temperature. Pushing the electric current with metal and simulto makes Taneous reading the current in the metal.

While several metals can be used as a core in the thermometer of resistance, platinum is the most common. One of the reasons is that platinum is chemically inert, so it will not respond with closeof the chemicals. Another, more important reason is that platinum is high heat resistant and remains stable under harsh conditions. This makes the platinum core particularly suitable for this purpose.

The internal core of the thermometer of the resistance may not change from the unit to the unit, but the connection configuration is often different. RTDs come in two-, three and four-wire samples, each of which is more accurate than the last. The wires are made of copper and have their own resistance. Fewer wires mean that RTD is not so able to handle resistance without throwing the temperature accuracy, while more wires give RTD better resistance, so it can better assess the temperature of the metal. The two -wire versions are best for approximate temperatures and are much cheaper; Three- and four-wire versions are best for accurate temperatures, but are more expensive.

Resistance thermometer is considered reliable and universal, but has restrictions. At temperatures exceeding 1,112° F (600 ° C) is difficult to prevent metal mantle RTD from platinum core contamination. Contamination means that the measurement will be inaccurate, which makes RTD unnecessary. At very low temperatures, such as -518 ° F (-270 ° C), it is impossible to assess the temperature based on resistance, because the resistance comes from dirt, not metals themselves.