How RTD works

A resistance temperature detector(RTD) is a temperature measuring device made of materials such as platinum whose resistance change is known at different temperatures. The R v/s T curve is used to determine the temperature. The platinum RTD's are the most stable, linear and accurate among all the RTD's
The Common material used to make RTD's are

• Platinum
• Nickel
• Copper

However Tungsten and Balco are also used to make RTD's but they are very rare. RTD's are commonly categorized by their nominal resistance at 0 degree celcius. Typical nominal resistance values for platinum RTD's include 100ohm and 1000ohm. The most common RTD's are PT100 and PT1000.

The Advantages of using RTD's for temperature measurement are

• Accurate
• Provide good stability and repeatability
• RTD's are also relatively immune to electrical noise and therefore well suited for temperature measurement in industrial environments, especially around motors, generators and other high voltage equipments.
• The resistance changes linearly with temperature so the measurement is quite simple.
  

The Disadvantages of RTD's are

• Lower temperature measuring range
• High cost
• The RTD's are not well suited to use in harsh environments compared to thermocouple.
  

The RTD's can be used to measure the temperature of the air, fluid..etc

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