Miniature thermocouple is one of the types of thermocouple sensor, the characteristics of big is small, play their unique role in many fields. Working principle of miniature thermocouple and the general working principle of thermocouple is the same, will be two different welding material a conductor or semi-conductor a and b, form a closed loop. When the conductor a and b two persistent point temperature difference between 1 and 2, occurs between the electromotive force, thus forming the size of a current in the circuit, this kind of phenomenon called the thermoelectric effect. Miniature thermocouple is small than a thermocouple, more can bend, heat resistance to high pressure, fast response time and the advantages of strong and durable, miniature thermocouple with thermocouple, thermocouple and assembly as measure temperature sensor, usually miniature thermocouple and display instrument, recorder and electronic regulator, at the same time, the miniature thermocouple also can be used as a prefabricated thermocouple temperature sensing element. Miniature thermocouple is particularly suited to small temperature measurement and control, and bending places is chemical, chemical, pharmaceutical and other industries indispensable measure temperature device. Technical parameters of precision grade level I or ii' Below 375 ° plus or minus 1. 5 degrees as the primary standard. Plus or minus 2. 5 degrees as the secondary standard 】 Nominal diameter Φ 1 Φ 0. 5Φ0。 35' Generally small diameter 】 Bending radius r 5 d or nominal pressure: the atmospheric packaging forms: insulation and pick up shells.