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