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The resistance of commercially available RTDs ranges from 10 to 25,000 W. More common ones are 100, 200, and 1000 W strain-free platinum (>99.999%) probes and 10 W copper probes. Generally, the higher the resistance, the less affected the RTD will be due to small resistance/voltage fluctuations in the lead wires and circuit.
Common metals used in RTDs include platinum, copper, nickel, BalcoTM (70% Ni-30% Fe), and tungsten. Their temperature ranges are listed in the following table.
| Material |
Temperature
Range |
Note |
| Platinum (Pt) |
-260~1000 °C
(-440~1800 °F) |
| Copper (Cu) |
-200~260 °C
(-330~500 °F) |
| Nickel (Ni) |
-200~430 °C
(-330~800 °F) |
Balco
(70% Ni-30% Fe) |
-100~230 °C
(-150~450 °F) |
| Tungsten (W) |
-100~1200 °C
(-150~2200 °F) |
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