RTD is actually the abbreviation of Resistance Temperature Detector, which means a special wire whose resistance virtually varies with the temperature; In adition, when it comes to the RTD material, it generally includes copper, platinum, nickel and alloy of nickel and iron.

PS: RTD resistance— 0℃ resistance usually considers as a nominal value. When 0 ℃ Ω platinum RTD resistor is in 1 ℃, its resistance is virtually 100.39 Ω; In 50 ℃, its resistance is 119.4 Ω. Furthermore, the error of RTD is less than thermal resistor. For platinum, the error is usually 0.01%; While for nickel, the erroe is 0.5%. Apart from that, the interface circuit of RTD and thermistor is basically the same except that less error and small resistance.