How do Type K Thermometers Work?

[Fred.Amoson]

Hello,

How do the thermometers known as "Type K" work? I've searched all around and have found no information on how they actually function.

 

[JimB]

You need to look for type K thermocouple.

They work by generating a small (few mV) voltage when the junction of two dissimilar metals is heated.

Look here:
https://en.wikipedia.org/wiki/Thermocouple

JimB

 

[Leftyretro]

Very simple. There are based on the Seebeck effect where any two dissimilar metal wires welded at one end will generate a millivolt DC voltage proportional to the heat. K type uses metal wires of Iron and Constantan.

Advantages: Low cost, rugged, very high temp range.

Disadvantage: cold reference temp circuit needed. Low noise amplification usually required.

If you don't require the very high temp range of a TC there are more modern and more accurate temp sensors, RTD, solid-state, etc that don't require as much support circuitry.

Here is a chart showing types of TC available:

https://www.omega.com/techref/colorcodes.html

More on the theory of operation:

https://www.electro-tech-online.com/custompdfs/2007/10/z021-032.pdf

Good luck

Lefty