What is the temperature coefficient of a standard Pt100 RTD?
A. 0.00385 Ω/°C
B. 0.385 Ω/°C
C. 38.5 Ω/°C
D. 0.0385 Ω/°C
View Answer
Answer: B
Explanation:
A standard Pt100 RTD has a resistance of 100 Ω at 0°C and follows the IEC 60751 standard.
Its temperature coefficient is:
- α = 0.00385 Ω/Ω/°C
To find the actual resistance change per degree Celsius for a Pt100:
Resistance change = 100 Ω × 0.00385
Resistance change = 0.385 Ω/°C
This means that near 0°C, the resistance of a Pt100 RTD increases by approximately 0.385 Ω for every 1°C rise in temperature.
For example:
- 0°C → 100.000 Ω
- 1°C → 100.385 Ω
- 10°C → 103.850 Ω
- 100°C → 138.5 Ω
Therefore, if all answer choices use the unit Ω/°C, the correct answer is:
B. 0.385 Ω/°C