What is the temperature at the voltage measuring end?
In the past, the cold junction was immersed in an ice bath, and the temperature at the hot junction was thereby referenced to zero degrees Celsius. Today, an electronic compensator measures the room temperature (usually with a resistance-temperature device, or RTD) and simulates the cold junction voltage for the ice point. * The Seebeck voltage is not linear with temperature. Organizations such as the National Institute of Standards and Technology have published tables of voltage vs. temperature for various combination pairs of thermocouple wire. These tables assume that the cold junction is at the ice point. Usually, the electronic compensator also applies these tables to the measurement, resulting in a direct, linear temperature-reading instrument. * Consider the effects of ambient temperatures. If you combine associated electronics with a thermocouple to measure at or near room temperature, the thermocouple is not really being used at all. The Seebeck voltage is near zero because th
