Which metal is most commonly used in industrial RTDs?
A. Copper
B. Aluminum
C. Platinum
D. Iron
View Answer
Correct Answer: C
Explanation:
Platinum is the most commonly used metal in industrial RTDs (Resistance Temperature Detectors) because it provides excellent accuracy, stability, repeatability, and resistance to corrosion.
The most widely used RTDs are:
- Pt100 → 100 Ω at 0°C
- Pt1000 → 1000 Ω at 0°C
Platinum RTDs are preferred because they:
Maintain stable characteristics over time
Provide highly accurate temperature measurements
Have a nearly linear resistance-temperature relationship
Operate over a wide temperature range
Resist oxidation and corrosion
Although copper and nickel RTDs exist, platinum has become the industry standard for process automation and temperature measurement applications.
For example:
- Pt100 at 0°C = 100 Ω
- Pt100 at 100°C ≈ 138.5 Ω
Because of its superior performance and international standardization under IEC 60751, Platinum is the most commonly used metal in industrial RTDs.
Therefore, Option C (Platinum) is the correct answer.