How to distinguish the positive and negative poles of K-type thermocouples?

The nominal chemical composition of the positive electrode (KP) is: Ni:Cr≈90: 10. The chemical composition of the negative electrode (KN) is: Ni:Si≈97.

K-type thermocouples have good linearity and high thermoelectric potential, making them suitable for use in oxidizing and inert atmospheres. However, K-type thermocouples cannot be directly used at high temperatures in atmospheres with sulfur, reducibility, or alternating reduction and oxidation, as well as in vacuum, and are not recommended for use in weakly oxidizing atmospheres. Its positive electrode is nickel chromium alloy (KP) containing 10% chromium, and its negative electrode is nickel silicon alloy (KN) containing 3% silicon.

How to distinguish the positive and negative poles of armored thermocouples? Based on this characteristic, magnets can easily distinguish the positive and negative poles of armored thermocouples.

As for the positive and negative poles of other thermocouples, it is also very simple. Firstly, there is a nickel chromium nickel silicon thermocouple, whose two wires have obvious color differentiation, one is green and the other is gray. The green wire is the positive pole. If it is an armored thermocouple wire, a small magnetic material can be placed on the negative pole surface, which is the gray wire. If it is attractive, this is the negative pole.