J Type Thermocouple
A thermocouple is made up of of two dissimilar conductors in contact with one another, which produce a voltage when heated. Thermocouples are used as temperature sensors for measurement and control and can also be used to convert a temperature gradient into electricity.
The J Type thermocouple (iron–constantan) is a common, general purpose thermocouple with a termperature range of approximately −40 to +750 °C, and sensitivity of 55 µV/°C. Wire color standard is white (+) and red (-).