Which materials are commonly used in the construction of RTD elements?

RTD (Resistance Temperature Detector) elements are designed to measure temperature through the principle that electrical resistance varies with temperature. The materials commonly used to construct RTD elements are chosen for their stable and repeatable resistance characteristics at various temperatures.

Platinum, copper, and nickel are widely selected for RTD applications. Platinum is particularly favored for its linear resistance-temperature relationship over a wide temperature range, excellent corrosion resistance, and stability. This makes it the most common material in high-precision applications. Copper and nickel also exhibit good temperature coefficients of resistance, making them suitable for specific applications, though not as widely used as platinum in industrial settings.

The other materials listed in the incorrect choices either do not have the necessary properties for stable temperature reading or do not provide the required accuracy and reliability across the temperature range for which RTDs are typically designed. Therefore, the choice of platinum, copper, and nickel aligns with the fundamental requirements for effective RTD construction.