Thermocouple vs. Thermopile — What's the Difference?

Thermocouples are commonly used in a wide variety of applications ranging from industrial to household use, like in gas appliances and temperature controllers. Thermopiles find more specialized uses, often in applications that require highly accurate temperature measurements, like in infrared sensors, gas analyzers, and radiometers.

In terms of construction, thermocouples are relatively simpler and more straightforward, often requiring no external power source to function. Thermopiles can be more complex due to their multiple thermocouple connections and may sometimes require an external power source or built-in amplification circuits for improved performance.

A thermocouple is essentially a temperature sensor that consists of two different types of metals joined together at one end. When this junction experiences a temperature difference, a voltage is generated, which can be measured to determine the temperature. A thermopile, on the other hand, is a collection of thermocouples that are connected in series or parallel, primarily to amplify the generated voltage for better accuracy.

Both thermocouples and thermopiles are durable and can withstand extreme conditions, but thermopiles generally offer higher sensitivity and accuracy because of the amplified output. However, thermocouples are typically faster in response time due to their simpler structure, which is a critical factor in certain applications.