For thermal sensors that are allowed to make contact with the subject or medium to be measured there exist a number of possible sensors
They are subdivided in several types:
- Thermocouples
- RTD’s (thermistors, Pt100’s, diodes, Semiconductor Temperature Sensors)
- Other types (expansion, bimetallic, optic, etc.)
For the first 3 types the most striking (dis)advantages are summarised in the table below.
| Thermocouple | RTD (Pt100) | Thermistor | |
| Operating Range | -200 °C to 2000 °C | -250 °C to 850 °C | -100 °C to 300 °C |
| Accuracy | Low 1 °C common | Very High 0.03 °C common | High 0.1 °C common |
| Linearity* | Medium | High | Low |
| Thermal Response** | Fast | Slow | Medium |
| Cost | Low | High | Low to moderate |
| Noise Problems | High | Medium | Low |
| Long term stability | Low | High | Medium |
| Cost of measuring instrument | Medium | High | Low |
** Thermal response is considered for the measuring element only, not its enclosure.
