GeoCorp Inc. is a premier manufacturer of RTD’s
The main difference between RTDs (Resistance Temperature Detectors) and thermocouples lies in how they measure temperature and their operating characteristics.
Here’s a clear side-by-side comparison
| Feature | RTD (Resistance Temperature Detector) | Thermocouple |
|---|---|---|
| Working Principle | Resistance changes with temperature | Voltage generated at junction of two dissimilar metals |
| Output Signal | Resistance (Ohms) | Millivoltage (mV) |
| Accuracy | High (better accuracy, especially at low/medium temperatures) | Moderate (can vary depending on type) |
| Stability | Excellent long-term stability | More prone to drift over time |
| Temperature Range | -200°C to 600°C (depends on material) | -200°C to ~2300°C (varies by thermocouple type) |
| Response Time | Slower (more mass, requires current source) | Faster |
| Cost | More expensive | Cheaper |
| Durability | Less rugged, more sensitive to mechanical shock | More rugged and suitable for harsh environments |
| Common Materials | Platinum (e.g., PT100, PT1000) | Nickel alloys, platinum/rhodium, Tungsten/rhenium |
| Power Requirement | Requires excitation current | No external power needed (self-powered) |
| Use Case Example | Laboratory, precision industrial processes | Furnaces, Heat treat, Waste Disposal, Cremation, Composite Curing, etc. |
Summary:
Choose an RTD if you need high accuracy, repeatability, and are measuring moderate temperature ranges in a controlled environment.
Choose a thermocouple if you need wide temperature range, fast response, ruggedness, and lower cost.
Let us know if you need help determining the best fit for your application.