Symbol for RTD

Resistance Temperature Detector (RTD), a resistance thermometer; RTD is a sensor that can provide temperature measurement and utilize the relationship between electrical resistance and temperature. RTDs are accurate in it’s precision; however temperatures above 1292°F (700°C) lose accuracy as the outer sheath degrades and the thermometer becomes exposed.

RTDs are most accurate with lower temperatures and come in two different types.  Traditional RTD uses metallic sensing element that results in a relationship between temperature and resistance as linear. The RTD thermistor uses a semiconductor sensor that powers a relationship between temperature and resistance.

A typical RTD diagram

Diagram of RTD

Functional operating range for the follow thermocouples:

  • Type J: -346 to 2192°F (-210 to 1200°C)
  • Type K: -454 to 2500°F (-270 to 1371°C)
  • Type T: -454 to 750°F (-270 to 400°C)
  • Type E: -454 to 1832°F (-270 to 1000°C)
  • Type N: -454 to 2372°F (-270 to 1300°C)
  • Type C: 32 to 4200°F (0 to 2315°C)
  • Type D: 32 to 4200°F (0 to 2315°C)
  • Type F: 32 to 4200°F (0 to 1343°C)
  • Type R: 32 to 4200°F (-50 to 1767°C)
  • Type S: -58 to 3214°F (-50 to 1767°C)
  • Type B: 32 to 3300°F (0 to 1816°C)
  • RTD (DIN): -328 to 1472°F (-200 to 800°C)