What Are The Advantages And Limitations Of A Thermocouple?

As temperature sensors, thermocouples have become instrumental to science and industry. They comprise two wires of differing metals that share a single, typically welded junction. Temperature changes generate voltage and allow thermocouples to convey specific measurements to operators. Clearly, they present distinct advantages in systems where precise temperature measurements are necessary. But what are some features that could be disadvantageous? 

Thermocouple Advantages

Thermocouples are temperature sensors that offer a simple, rugged, and relatively inexpensive answer to many industries’ needs to measure temperature at various points in their operations. They are used in items from home appliances to jumbo jets and spacecraft–that’s quite the gamut. 

One reason that thermocouple sensors are so ubiquitous is that they can be made using very thin wire. This means that they are ideal for measuring temperature in even the most delicate of situations and that their response time is relatively short. Thermocouples can also often be connected together to form a series of sensors, which allows for a stronger overall voltage response. 

One undeniable advantage to thermocouples is the wide range of temperatures that they can sense. These can include anything from -100 to 2600°C. Thermocouples are also built to be rugged and durable, suitable for countless applications, even those that require direct contact with the material being measured.

Thermocouple Limitations

Disadvantages to using thermocouples are typically circumstantial. Since the output of a thermocouple is very low, they can sometimes have accuracy limited to roughly 1℃ or about 2℉. The result makes thermocouple calibration necessary and is thus compared to a reference value. Thankfully, electronic ice-point reference circuits have replaced traditional ice baths and allowed for greater portability. 

Thermocouples also have a weak output signal, and may necessitate additional, external equipment in order to amplify and interpret results. At the same time, the low-voltage output can be muddled by interference from nearby electrical devices and machinery, common in some manufacturing environments. Grounded shielding can offer reliable results.

Another potential limitation is the possibility of corrosion, seeing as thermocouples are made using two dissimilar metals. Corrosion will naturally affect calibration and thereby the accuracy of measurements. Modern thermocouples that will be used in harsh or corrosive environments are typically crafted with a protective stainless steel sheath to prevent corrosion, but maintenance is always key to ensure good long-term results. And even though thermocouples can sense a wide range of temperatures, they often display a low sensitivity to small temperature changes.

RAM Sensors Knows Thermocouple Sensors

Whatever your application or thermocouple sensor needs, you can find what you’re looking for at RAM Sensors. As seasoned temperature sensor manufacturers, we are dedicated to know what will work best for any given application. Contact us today to inquire about a specific model of thermocouple or to discuss your upcoming project.