The Science Behind the Thermocouple: the Seebeck Effect


Thermocouples are small but complicated machines. The way they function is pretty mystifying to anyone not terribly familiar with electronics, or science, or math, really. Thermocouples can convert temperature into energy, and they can also measure temperature levels in a variety of substances. But the science behind them is quite remarkable.

The thermocouple functions according to the Seebeck effect. The Seebeck effect is named for the scientist who discovered it, Thomas Johann Seebeck. To put the Seebeck effect in its most basic terms, the effect’s namesake found that when there was a difference in temperature between two pieces or kinds of metal it would affect a compass needle. This movement in the needle was later determined to be the result of the two metals generating electricity. Once the Seebeck effect had been proven to be a recurring phenomenon, the thermocouple was born. Because the thermocouple measures the temperature between two objects, it must be set at a control temperature in order to obtain an accurate reading. If you know what the base temperature you’re beginning with is, you will be able to determine rather easily the temperature of the object of your choice.

Now the device is used in factories, the food service industry, and especially in the steel making trade. The thermocouple’s incredible versatility makes it an ideal tool for use not just in these areas of business, but in the home as well. One of the most popular ways you’ll see a thermocouple employed is on your gas water heater. Used in this capacity the thermocouple ensures that your water heater won’t become a danger to your home. Another place you’ll see a thermocouple in your home is on your gas furnace. Just like in the water heater the thermocouple regulates the gas output according to whether the pilot is lit. When it comes to home heating, the thermocouple is your own personal bodyguard.