Comparison Between RTD and Thermocouple

The comparison between RTD and Thermocouple is listed in the below table.

Parameter	RTD	Thermocouple
Principle of operation	Resistance changes with temperature	The voltage is induced proportional to temperature
Type of transducer	It is a Passive type transducer hence dc source is required for its operation.	It is an Active type transducer hence external dc source is not required for its operation.
Temperature range	-2000 C to 6500 C	-2000 C to 11000 C
Sensitivity	Excellent	Good
Response time	Good	Excellent
Cost	High	Moderate
Accuracy	Very good	Moderate
Size	Large	Small
Material used	Platinum, Nickle, Copper, Semiconductors, etc.	Iron-constantan, Copper-constantan, etc.
Linearity of characteristics	Non-linear	Non-linear
Compensation	Not required	Cold junction compensation is required
Applications	For shorter temperature range applications	For wide temperature range applications

RTD

Thermocouple