Thermocouple vs RTD (PT100) Comparison

**Subtitle**: Technical Differences and Selection Guide for Temperature Sensors

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Introduction

**Thermocouples** and **RTDs (PT100)** dominate industrial temperature measurement. Engineers often struggle to choose between them. This guide provides a thorough technical comparison to inform your decision.

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Part 1: Working Principles

Thermocouple

Based on the Seebeck Effect: two dissimilar metals generate voltage when junctions are at different temperatures.

RTD (PT100)

Based on resistance temperature effect: platinum resistance changes predictably with temperature. R₀ = 100Ω at 0°C.

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Part 2: Performance Comparison

| Parameter | Thermocouple (K) | RTD (PT100) |

|-----------|-----------------|-------------|

| Temperature range | -200°C to 1260°C | -200°C to 600°C |

| Standard accuracy | ±1.5°C (Class 1) | ±0.15°C (Class A) |

| High grade accuracy | ±0.4°C | ±0.1°C |

| Response speed | Fast (0.1-5s) | Medium (1-10s) |

| Long-term stability | Fair | Excellent |

| Linearity | Non-linear | Highly linear |

| Cold junction | Required | Not needed |

| Lead wire | Compensating | 3/4-wire |

| Noise immunity | Lower | Higher |

| Cost | Lower | Higher |

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Part 3: Application Selection

Choose PT100 When:

· - Precision control (±0.5°C)

· - Low temperatures (-200°C to 0°C)

· - Long-term monitoring

· - Laboratory/standards work

· - Food/medical applications

Choose Thermocouple When:

· - High temperatures (>600°C)

· - Fast response needed

· - Harsh environments

· - Cost-sensitive

· - Wide range coverage

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Conclusion

Match the sensor to your application requirements. PT100 excels at precision; thermocouples handle extremes.

**BANBEKE** supplies both sensor types:

· - Thermocouples: K, J, E types

· - RTDs: PT100, PT1000, Class A/B

· - Transmitters and accessories

**BANBEKE Industrial Heaters**