What is the difference between rtd and thermocouple

By calculating the RTD resistance, the temperature can be determined. RTD elements are made using different materials such as nickel, platinum, copper etc. RTDs are used to measure temperature in laboratories and industrial processes, and they are known for their accuracy, stability, and repeatability characteristics.

They can be used in all but the highest temperature industrial processes. Made using platinum, RTDs are very stable and are not affected by corrosion or oxidation. They boast high repeatability, which means that they can measure identical temperatures accurately even when exposed to repeated heating and cooling cycles with minimal discrepancies.

Therefore, they are considered ideal for temperature measurements in industrial environments. What is Thermocouple? A thermocouple is an electrical device which is extensively used for measuring temperature. It consists of two dissimilar electrical conductors forming electrical junctions at different temperatures. This means that the thermocouple measures unknown temperature of the body with reference to the known temperature of the other body. Thermocouples can measure a wide range of temperatures and they are self powered and require no external form of excitation.

Thermocouples are easy to use, and they are the most durable temperature sensors. They are very user friendly and help to retrieve results quickly. The major advantage that a thermocouple offers to us is the temperature range.

It can be used for a very wide range of temperatures. Thermocouples can be made using common materials such as nickel, iron; They are also made of rare and expensive materials such as rhodium and platinum. For greater accuracy, they should be placed as close to the measured equipment as possible, or even inside. However, if installed correctly, thermistors can have a typical accuracy of 0.

Conclusion: RTDs are more accurate than thermocouples, and thermistors can be more accurate than either but only if installed correctly and used in a limited temperature range. A temperature sensor must provide consistent output for the applied input if you plan to rely on its data. A stable sensor can offer drift-free measurement for nearly a decade if set and maintained properly.

The RTD provides excellent stability, typically 0. Thermistors usually have a drift of 0. Does the environment have an effect on the temperature measurement? Yes, it surely does.

Vibrations and mechanical shocks can affect RTD measurements. However, the ceramic in RTDs make them unsuitable against high vibrations. Fortunately, thermocouples resist vibration very well. Thermistors in general are relatively stable. The cost of the entire temperature sensor depends on the type of final products And of course you have to include installation, so make sure you add that to your calculations.

However, in general, thermocouples tend to be the most cost-efficient, followed by thermistors and then RTDs. Response time is how quickly the temperature sensor gives output with the change in the measuring temperature. Every sensor has a finite response time. RTDs possesses medium response time however, thermocouple has medium to fast response time. Thermistors also have a medium to fast response time. RTDs, as passive sensors, require an electrical current to work. As the current passes through the element and increases resistance, the increased resistance raises the temperature.

There are a number of benefits to using thermocouple temperature sensors; this includes its wide temperature range. They are also very robust, especially when using mineral insulated cable. Thermocouples are a more simple device and versatile. You can have fast response versions or hand held probes, as well as types which are designed to be used in chemicals or harsh environments. Mineral insulated versions offer a very durable sensor which can withstand vibration and harsh environments.

You can read detailed technical information about thermocouples in our technical reference page. The main benefits of an RTD sensor Pt, Pt is the good accuracy over a fairly wide range and combined with excellent stability, this is in contrast to a thermocouple which is less accurate, less stable and can drift over time.

RTD Sensors are more suitable for lower temperature ranges, where higher accuracy and repeatability is needed. They also need to be immersed in the media due to stem conduction errors.