#Thermocouple or #RTD/PT100 ?

Probe sensorThis is s common question asked when customers purchase one of our temperature controllers. Both of them have their advantages and disadvantages. Below are the main reasons for the choices.


Thermocouples consist of two dissimilar conductors connected together, hot junction and cold junction which measures the thermo-electromotive force


  • They have a simple build construction
  • Very inexpensive compared to PT100/RTD sensors
  • No power supply required, produces its own millivolt signal
  • Sturdy construction and can be adapted to suit applications
  • Wide measuring range


  • Non-linear over range
  • Reference junction point required
  • Long term drift
  • EMF low in some cases
  • Lower sensitivity

RTD/PT100 (Resistance Temperature Detectors)

PT100 are connected to temperature controllers or transmitters with 2 or 3 wires, this reduces the error in the leads themselves and offer higher accuracy.


  • More accurate than thermocouples
  • Very stable
  • More linear than thermocouples


  • Power supply required
  • Higher costs
  • Low resistance value
  • Self heating




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