A resistance thermometer or resistance temperature identifier (RTD) is a gadget which estimates temperature through the resistance of a guide. Resistance of the guide can differ with time. This property of the guide is utilized for modern temperature estimation. The RTD's basic role is to create a resistance modification in light of temperature.

Metals normally display high temperature coefficients, showing resistance increments as temperature climbs. Then again, carbon and germanium normally exhibit low temperature coefficients, in this way showing a resistance decline with expanding temperature.

The resistance thermometer has a touchy component that is produced using the most flawless metals like platinum, copper, or nickel. There is an immediate association between the resistance of the metal and temperature. By and large, platinum is utilized in resistance thermometers because of its high exactness, soundness, and its capacity to endure very high temperatures.

Metals like gold and silver are not utilized for RTD heat follow on the grounds that they don't show the high necessary resistance, they have low resistivity. While a material like tungsten has high resistance however is exceptionally weak. Copper is in many cases used to make the RTD component as it has low resistivity and is a less expensive metal. The main disadvantage to copper is that is has less linearity.

The most extreme temperature of the copper is around 120C. A RTD material is produced using either platinum, nickel, or nickel amalgams. Nickel wires function admirably inside a specific temperature range yet are not straight. The RTD sensor requires a guide with a high resistivity so a limited quantity of guide volume can be utilized. The resistance ought to shift however much as could be expected with temperature.

The resistance thermometer is put inside a defensive cylinder to hold it back from becoming harmed. Platinum wire is twisted around an earthenware bobbin to shape the resistive component, which is put inside a pure or copper steel tube. Lead wire is connected to the component and outer lead and covered with a protected cylinder to safeguard against short circuits. Earthenware is a separator for high-temperature components, while glass or fiber is utilized for low-temperature.