A thermocouple is a temperature sensor based on the Seebeck effect, composed of two conductors or semiconductors of different materials forming a closed circuit. It calculates temperature by measuring the thermoelectromotive force generated by the temperature difference between the two ends.
Structure and Principle
A thermocouple mainly consists of a thermoelectrode, an insulated protective sleeve, and a junction box. It generates an electromotive force through the temperature difference between the measuring end (hot end) and the reference end (cold end). The cold end is usually maintained at a constant temperature (e.g., 0°C), and the thermoelectromotive force has a functional relationship with the temperature difference, which is converted into the actual temperature using a calibration table.
Application Features
No external power supply required: Utilizes material properties to directly convert temperature into an electrical signal, making it suitable for complex industrial environments.
Wide measurement range: Common types such as K-type, J-type, and T-type cover scenarios from low to high temperatures.
Simple structure: Industrial thermocouples use a combination of ceramic insulating tubes and metal protective tubes, adapting to complex medium environments.
Industrial Applications
Industrial thermocouples must undergo factory tests (using standard platinum-rhodium thermocouples and potentiometers). Common faults include reversed polarity of wires and damaged ceramic tubes.