Thermocouples: What’s the 101?



Electrical engineering is one of the most lucrative careers you can cultivate in the US, on account of the unilateral importance of electricity and electrical products to practically every American citizen. From the development and maintenance of power grid infrastructure to the design and manufacture of essential electrical goods, engineers enjoy a plurality of potential pathways – all of which have a high demand for workers and a high salary to boot.

Starting down any of these paths can be difficult though, given the extensive education and vocational skills required to excel. A small but essential part of this is understanding the components that make up our electrical devices and systems – how they work and how they can be properly (read: safely) utilised in circuit or system design.

This piece will take one such component and drill down into its specifics, to demonstrate the depth of knowledge necessary to succeed in electrical engineering while dispensing some in the process. Without further ado: what is a thermocouple? And what do you need to know about it?

What are Thermocouples?

Thermocouples are basic electrical components, designed as temperature-measuring sensors. They comprise, in essence, two conductive metals of different types conjoined; as the temperature of one metal changes, a voltage is generated across both. This is called the Seebeck effect.

The voltage generated across the metals is directly proportionate to the difference in temperature between the warmer end and the colder end. This means the voltage can be translated to temperature – but also has some clever practical applications in circuit design.


Thermocouples come in various designs or ‘types’, assigned letters according to their material composition and temperature range. B-type thermocouples are composed of rhodium and platinum and can be capable of measuring temperatures over 3000 degrees Fahrenheit. Meanwhile, T-type thermocouples comprise copper and constantan (an alloy of copper and nickel) and measure temperatures in the -300F range.


These different types of thermocouples have different uses across numerous industries and technologies. Their applications range from circuit protection and temperature readouts in consumer appliances to deep space temperature measurements and far, far beyond. Perhaps most commonly though, thermocouples are used in manufacturing and assembly lines to monitor and control processes. The voltage supplied by the thermocouple can be used as a control voltage, switching systems like failsafes on and off or changing values elsewhere in a system.


The thermocouple is a fascinating device with an extremely simple construction, that utilizes an interesting thermoelectric phenomenon to achieve a wide variety of potential services and outcomes. It is an excellent example of how deep and rewarding electrical engineering can truly be – and an excellent example of the wealth of vocational knowledge that can be acquired, for the betterment of electrical engineering and design.