A hot junction is the point where two dissimilar metals are joined together in a thermocouple. This is the part of the thermocouple that is exposed to the temperature being measured.
When the two metals are joined and heated to different temperatures, a voltage is generated. This voltage is directly proportional to the temperature difference between the two junctions.
In essence, the hot junction acts as the sensing element of the thermocouple, converting the temperature into an electrical signal that can be measured and interpreted.
What is a Cold Junction and a Hot Junction?
A hot junction and a cold junction are the two essential components of a thermocouple.
- Hot junction: This is the point where two dissimilar metals are joined together and exposed to the temperature being measured. The temperature difference between the hot junction and the cold junction generates a voltage.
- Cold junction: This is the reference point of the thermocouple, typically kept at a known temperature (often 0°C). The voltage generated by the thermocouple is directly related to the temperature difference between the hot junction and the cold junction.
In essence, the hot junction senses the temperature, while the cold junction provides a reference point for accurate measurement.
The temperature difference between the hot junction and the cold junction is what determines the voltage output of the thermocouple, which can then be used to calculate the temperature at the hot junction.
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