What is ordinary type thermocouple and thermocouple _ instrument1

If we are to use normal thermocouple is first of the two kinds of thermocouple has certain understanding. Ordinary thermocouples generally by the hot electrode, insulation tube, to protect casing and junction box parts, and the thermocouple is the electric heating wire, insulation material and metal protective casing combination after assembly, after stretching processing from a combination of a solid. But it takes a special electric coupling of electrical wires to pass, this kind of wire we called compensation conductor. Different electric I need different compensation conductor, its main function is connected to the electric coupling, electric heating my reference end away from the power, so that the reference temperature stability. Compensation wire is divided into compensation type and extended type two kinds, extend the chemical composition of the wire and the compensation of electro-thermal coupling is the same, but in practice, to extend the type of wire is not use of the same material and electric coupling metals, generally USES and electric coupling with the same wire instead of electron density. Compensation and electric coupling connection of the wire are generally not very clear, the positive connection of the electric coupling compensation conductor should be red line, while the cathode connecting the rest of the color. Most of the material compensating lead wires are commonly used copper nickel alloy. Thermocouple is one of the industry commonly used temperature detecting element. Working principle of the thermocouple: is based on the seebeck ( seeback) Effect, that is, two different components of conductor ends connected into a circuit, such as two different connection end temperature, then to produce the physical phenomenon of thermal current in the circuit. Its advantage is that (1) high accuracy of measurement. Because of thermocouple direct contact with the object being measured, not affected by intermediate medium. (2) the measurement range. The commonly used thermocouple from - 50 ~ + 1600 ℃ can renew edge measurement, some special thermocouple low measurable to - 269℃（ Such as gold iron nickel chrome) Up to + 2800 ℃ ( Such as tungsten-rhenium thermocouples) 。 3. Simple structure, easy to use. Thermocouple is usually composed of two different kinds of metal wire, but is not limited by the size and the beginning of, outside has protective casing, which are very convenient. Basic principle of thermocouple temperature measurement will be two different welding material A conductor or semi-conductor A and B to form A closed loop, when the conductor A and B two persistent point temperature difference between 1 and 2, occurs between the electromotive force, and thus form the size of A current in the circuit, this kind of phenomenon called the thermoelectric effect. Thermocouple is in using this effect to work.