Type J Thermocouple: The type J is also very common. It has a smaller temperature range and a shorter lifespan at higher temperatures than the Type K. It is equivalent to the Type K in terms of expense and reliability.
|Thermocouple Type||Temperature Range (Continuous)*||Temperature Range (Short Term)*||Thermocouple Materials||Contact Size||Termination|
|K||+32° to +2,012°F (0° to +1,100°C)||-292° to +2,372°F (-180° to +1,300°C)||Chromel & Alumel||#16, #20, #22D||Crimp|
|E||+32° to +1,472°F (0° to +800°C||-40° to +1,652°F (-40° to +900°C)||Chromel & Constantan||#16, #20, #22D||Crimp|
|J||+32° to +1,382°F (0° to +750°C)||-292° to +1,472°F (-180° to +800°C)||Iron & Constantan||#16, #20, #22D||Crimp|
|T||-301° to +572°F (-185° to +300°C)||-418° to +752°F (-250° to +400°C)||Copper & Constantan||#22D||Crimp|
Type J thermocouple is an exceptionally normal and universally useful thermocouple. It has more modest temperature range and a more limited life expectancy at higher temperatures. It comprise of positive leg made of an Iron wire and negative leg made of a Constantan ( Copper-Nickel ) compound wire. Because of the Curie Point of the iron at 770 °C Type J has a restricted temperature scope of - 40°C to 750°C.It ought not be utilized at high temperatures in an oxidizing environment as iron goes through a sub-atomic change and for all time loses its standard voltage yield versus temperature. It doesn't recuperate when the iron is cooled. Type J has affectability of approx 50 microvolts/degree C .The costs and dependability of Type J is same as Type K. For legitimate working of J Type thermocouple decrease environment is wanted and use at low temperature is additionally not suggested.
Among a wide range of thermocouple Type J is the least expensive thermocouple
J Type thermocouple gives 1mV yield for 18 degree C
Valuable in diminishing airs
On the off chance that J Type is secured by compacted mineral protection and proper external sheath, it is useable from 0 to 816°C, (32 to 1500°F). It isn't powerless to maturing in the 371 to 538°C, (700 to 1000°F) temperature range
In J Type thermocouple positive leg is composed of Iron(Fe) and negative leg is composed of mixture of Copper 55% and Nickel wire 45% which is known as constantan alloy.