Thermocouples
Thermocouples are the simplest but most versatile of the temperature sensors. Thermocouples can measure very low temperatures found in cryogenic applications as well as high temperatures typical in combustion and molten metal applications. Because of their simple design they can be made into shapes and form factors ideally suited for liquid, gas, or solid surface temperature measurement. For applications requiring fast response time few sensors can match the speed of a fine gauge thermocouple.