Hello, friends welcome to the new post. In this post, we will have a detailed look at Difference Between RTD and Thermocouple. both of these two instruments are used for the measurement of temperature. Also called temperature sensor the difference is the operation over which these two devices operate.
RTD consists of one metallic wire that resistance change measures the temperature and the thermocouple uses two wires for temperature measurements. Here we cover the basics of these two devices with the details. So let’s get started with the Difference Between RTD and Thermocouple.
Difference Between RTD and Thermocouple
What is RTD
- The RTD stands for resistance temperature detector type of sensor that is used to find the value of temperature.
- With the resistance increment, it measures the value of temperature.
- it is a passive module that does not generate any output.
- Any exterior device is employed to find the resistance of any device when a small value current is passed through it.
- Generally, one milliampere current is provided to this device to operate.
- The RTD is created through the use of numerous standards curvatures and tolerances. The generally used curve for this module is DIn.
- That defines the relation between resistance and temperature of platinum.
- The construction of RTD is simple that comprises of wire wounded about the ceramic material.
- The wire of this device is created through pure substances like nickel, copper, etc.
- The material of the wire should give an accurate value of resistance to temperature so temperature measurement from the instrument occurs accurately.
- Due to its fragile nature used normally covered with the protective cover
RTD Types
- There are 3 main types of RTD first one thin film second one is wire wound and the third is in the form of coil employed at the industrial level
Carbon RTD
- It is less costly and normally used in different applications. For low-value temperature measurements, it used. Since they offered less value for hysteresis.
Strain Free RTD
- It consists of a coil that exists in the cover having inert gases in that covering. It is used to measure the maximum value temperature to 961
- With the temperature increment, its structure can be expanded due to the usage of a platinum coil that is loose structure.
Thin Film RTD
- It consists of detection compone that is created through the use of a thin sheet of resistance substance generally platinum.
- The thickness of a sheet or layer of platinum is one to ten nanometers. and layer has a coating of epoxy that protects the device.
What is Thermocouple
- The thermocouple is an electrical instrument that comprises 2 metallic rods of a different electrical conductor and makes an electric junction.
- The thermocouple generates a temperature-dependent voltage as a consequence of the setback factor.
- The available thermocouples are costly and provided with connectors and can find the value of temperature at different ranges.
- Its drawback is that there is a one-degree error that can exist in this device.
- This module is generally used in industrial providing different uses like kilns, gas turbines, and other types of different processes used this device.
- They can easily get through the electronic market with a less cost-changeable facility and consist of standard-level connectors and are used to find different values of temperature.
- The best feature is that they get power on a self basis not need any extra power source for them.
- Its drawback is that is less accurate it causes a fault in the case of measurement of temperature value less than one centigrade.
- They are employed at the industrial level and in different laboratories.
- Used to measure the temperature of the kiln, gas turbine, engines, and different industrial processes.
- also used in homes, and offices as temperature measurement devices in thermostats.
Comparison Between RTD and Thermocouple
Why use a thermocouple?
There are many features of thermocouple sensors, which come with a larger temperature range. As the main type of thermocouple, the K type used in larger temperatures ranges from zero to 1100 degrees.
Some modules come with a high-temperature range, which can measure 2000 degrees.
Thermocouples are simple devices and can work for different chemicals and harsh conditions.
Why use an RTD sensor?
RTD comes with high accuracy with larger ranges and has good stability, while the thermocouple is low accurate and less stable.
RTD sensors are best for use in low-temperature ranges, where high accuracy and repeatability are used.
It also uses standard electrical wiring and thermocouples needing compensated alloys and connectors are length to connection of the instrument.
Materials used for thermocouples
The basic types of thermocouples are K, J, T, and E. These letters define a certain combination of two different metals used for thermocouples.
These metals are used for good features like high accuracy, response time, and temperature ranges.
K thermocouple is created with chrome and aluminum metals and used for high-temperature conditions such as furnaces and boilers.
J type is made with iron and Constantan metals and used for refrigeration where low temperature is needed.
Read also
- Difference Between RTD & Thermistor
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That is a detailed post about Difference Between RTD and Thermocouple if you have any further query ask in comments. thanks for reading have a nice day. Thanks for reading.