#WishIknew How do thermocouples convert heat to electricity?


When you have a question about process automation that needs a short answer, let us know with #WishIknew and #Visaya! We’ll reply with a #WishIknew post. It’ll give a quick explanation, then some related articles, videos, and reviews if you want to know more.

I wish I knew how do thermocouples convert heat to electricity!

This is a fun question because it involves science! We also have other content here at Visaya where we explain thermocouples (TCs) in detail. However, let me give you a quick answer for this question. If you want to know more, then you can check out those posts.

A TC has in it two different metals joined at one end. For instance, a type-K uses chromel and alumel. When you heat the sensor, the heat creates a difference in temperature between the joints, resulting in a voltage. We call this the thermoelectric effect, and this voltage is proportional to the heating temperature.

Every type of TC has a reference table, so make sure you use the right table. For a type-K, you find its table, look up the voltage generated, and voila! Your temperature!

You can read about TC calibration, cold junctions, and more here:

#WishIknew – When do I use a thermocouple compensating cable? – When you use a thermocouple, you can connect it to your control system or transmitter in many ways. The simplest way uses an extension cable or compensating cable.

#WishIknew – How do you calibrate a thermocouple? – You have several ways that apply to all thermocouple types, but the right way for you depends on your conditions. However, you always need a calibration furnace. So let’s go through the options.