What is the J type thermocouple? Iron - J type thermocouple Copper nickel thermocouple, also known as the iron - Constantan thermocouple, also is a kind of high price inexpensive metal thermocouple. Its positive electrode in the name of the chemical composition of pure iron, the negative is copper and nickel alloy, are often vague call constantan, its nominal chemical composition of: 55% copper and 45% nickel as well as a large number of manganese is very critical, cobalt, iron and other elements, although it's called constantan, but differs from that of nickel and chromium - Constantan and copper - Constantan constantan, so can't use EN and TN to exchange. Iron - Temperature range of measurement for the cover - constantan thermocouple 200 ~ 1200 ℃, but usually use the temperature field of 0 ~ 750 ℃.
J type thermocouple with thermoelectric emfs is bigger, good linearity, high sensitivity, stability and average sex good, cheap prices, and other advantages, is widely adopted by the player.
J type thermocouple at http://www. wuxiyibiao。 Com/can be used in the vacuum, oxidation, recovery and inert atmosphere, but the positive iron oxide in low temperature quickly, so the use of temperature have been bound, nor indirect without maintenance for curing under low temperature environment.