Although PT100 and PT1000 platinum resistance thermometers (PRTs) share the same operating principle—measuring temperature via the predictable change in platinum wire resistance—their nominal resistance values differ significantly. PT100 has a resistance of 100Ω at 0°C, while PT1000 measures 1000Ω. This fundamental difference leads to distinct advantages in various application scenarios.
1. Key Technical Specifications
| Feature | PT100 | PT1000 |
| Resistance at 0°C | 100 Ω | 1000 Ω |
| Resistance Change Rate | ~0.385 Ω/°C | ~3.85 Ω/°C (10x higher) |
| Sensitivity | Standard | High |
2. Performance Breakdown
A. Sensitivity to Lead Wire Resistance
Lead wire resistance is a common source of error. For a PT100, a lead resistance of just 2Ω can cause a measurement error of approximately 5°C. In contrast, for a PT1000, the same 2Ω lead resistance results in an error of only about 0.5°C.
Advantage: PT1000 is superior for long-distance measurements or when using standard 2-wire cables.
B. Excitation Current and Signal Strength
Current Requirement: To avoid overheating, PT1000 typically requires only 1/10th of the excitation current needed by a PT100 to produce the same voltage signal.
Signal-to-Noise Ratio (SNR): Under the same current, PT1000 generates a voltage signal ten times stronger than PT100, making it more resilient to circuit noise and simplifying signal conditioning design.
C. Self-Heating Effect and Power Consumption
Self-Heating: The heat generated by the sensing current ($I^2R$) creates errors. Since PT1000 operates at much lower currents, its self-heating effect is significantly reduced.
Power Efficiency: PT1000 consumes much less power, making it the ideal choice for battery-powered and portable devices.
D. Cost and Market Presence
PT100: Historically more popular due to lower costs and legacy compatibility with older industrial PLCs and controllers.
PT1000: While slightly more expensive, its popularity is rising rapidly as manufacturing costs decrease and the demand for low-power IoT devices grows.
3. Conclusion
PT1000 can be viewed as an optimized version of the PT100. It inherits the excellent linearity and stability of platinum sensors while solving the inherent weaknesses of high power consumption, self-heating, and lead wire interference.
Recommended Choice:
Choose PT100 if you are integrating with legacy industrial equipment that only accepts 100Ω inputs.
Choose PT1000 for all new electronic designs, especially for IoT, portable instruments, and long-cable applications.
