RTD vs thermocouple

RTD sensor measure temperature based on the resistance changes in a metal resistor inside while in thermocouple uses two metal wires to produce a voltage relative to the temperature present junction between them. Here the post gives information about the difference between RTD and thermocouple to better understand this topic.

The main key difference between RTD and thermocouple are listed below:
  • RTD accuracy 0.1 to 1 °C and thermocouple accuracy 0.5 to 5 °C.
  • Long term stability of RTD has 0.05 °C/ year while thermocouple has variable.
  • Thermocouple has linear while RTD has fairly linear.
  • RTD has rarely susceptible, but thermocouple has susceptible.
  • RTD has generally slow response time(1 to 50 s) while thermocouple has generally fast response time ( 0.01 to 10 s).
  • Temperature range is around 200 to 650 °C while thermocouple is around 200 to 1750 C°
  • RTD has a high cost, thermocouple has a low cost.
  • RTDs are superior to a thermocouple in that there are more accurate and more repeatable.
  • RTD has constant voltage and current while thermocouple has self-power.
  • RTD produce better and more reliable measurement while thermocouple is cheap, more durable and can measure a bigger range of temperature.