#WishIknew What is a thermocouple?


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 what is a thermocouple!

We have many types of temperature sensors on the market – resistance temperature detectors (RTDs), infrared sensors, thermistors, silicon diodes – the list goes on. But depending on your process requirements, a thermocouple may be your best option.

Usually, companies use thermocouples in high-temperature areas where RTDs fear to tread. Unfortunately, thermocouples have less long-term accuracy than RTDs because of that same heat.

Thermocouples have two different metals inside and use the thermoelectric effect to measure. That means that when you heat one end of the sensor, each metal will react differently. This difference will generate millivolts at the other end in proportion to the temperature at the heated end.

You may need a special table of reference to find the relation between the millivolts and the temperature. Some transmitters can do this for you, too.

These articles have more information:

Your friendly neighborhood temperature sensor! – Is it hot in here, or is it just me? Regardless, let’s talk temperature sensor! This basic variable is necessary to a variety of processes and segments. In most cases, you need to monitor exact temperatures, and in some, you need precise control. When you learn about temperature sensor from the maintenance point of view, you’ll find that you only need to consider certain points to choose the right sensor for your application.

Temperature measurement and control systems! – Today, you have tons of ways to connect your instrumentation to your control system, but as always, all the options have good points and bad. With an application where you have to connect temperature sensors to your system, which option(s) will work best for you?