Question

Compare RTD and Thermistor

Answer 1

RTD	Thermistor
RTD is made up of metals.	Thermistor is made up of semiconductor Materials
Metals have Positive Temperature Coefficient (PTC) of resistance. Hence the resistance of RTD increases with an increase in temperature and decreases with a decrease in temperature	Semiconductor materials have Negative Temperature Coefficient (NTC) of resistance. Hence, the resistance of a thermistor decreases with an increase in temperature and increases with a decrease in temperature.
The resistance temperature characteristics of RTD's are linear.	The resistance temperature characteristics of thermistor are highly nonlinear.
It is less sensitive to temperature compared to thermistor.	It has large temperature coefficient of resistance i.e. thermistor highly sensitive to temperature compared to RTD.
It has-a wide operating temperature range i.e., minus 200 to plus 650°C.	It has low operating temperature range compared to RTD i.e., minus 100 to plus 300°C.
RTD's provide high degree of accuracy and long term stability	Thermistors provide less degree of accuracy and short term stability
They have low selfresistance.	They have high self-resistance. Thus, they require shielding cables to minimize interference problems.
RTD's are relatively larger in size. They are costlier as compared to thermistor.	Size of thermistors is small. They are not costlier as compared to RTD

Answer 2

RTD	Thermistor
Made of metals which are good conductors of electricity e.g. copper, platinum Nickel	Made of metallic oxides such as cobalt, manganese, nickel etc.
Positive temperature coefficient of resistance.	PTC and NTC both types are available
Temperature range: -100 C to 650 C.	Temperature range: -50 C to 300 C
It has linear temperature versus resistance curve.	It has nonlinear temperature versus resistance curve.
As made of metal they are more stable.	As made of metal oxide they are less time stable.
They have better reproducibility and low hysteresis.	They have less reproducibility and more hysteresis.
Relatively bigger in size.	Thermistors are quite small in size.
Cost is high	They are not costlier as compared to RTD