A Resistance Thermometer is also refereed as a resistance thermal device (RTD). It is basically a thermometer generally for metals which pushes electricity through the metal and judges its temperature which is based on the resistance. Platinum is the most common metal widely used in a Resistance Thermometer. There are various RTD types, measured largely on how many wires are integrated in the device, here more wires stands for better accuracy. . While it is a trustworthy device, a Resistance Thermometer is not used at temperatures above 1,112° Fahrenheit (600° Celsius) or below -518°F (-270°C) because of complications.