Temperature is probably the most commonly measured physical parameter. Appropriate temperature sensor selection is essential. Designers have to decide on the best technology to employ considering the design brief. The sensor design comprises the employed sensor technology and the protection of the sensor from the process. This article covers the choice of temperature sensor selection.
Temperature Sensor Selection Technology Review
Each common technology has attributes:
| Thermocouple | Thermistor | Resistance Thermometer | Digital Sensor | Infrared | |
| Temp Range °C | -270 to +2000 | -90 to + 130 | -200 to + 600 | -10 to +85 | -50 to 3000 |
| Cost | Medium to Very High | Low | Low | Medium | High |
| Instrumentation | Readily Available or designed on a board | Designed in Circuit board | Readily Available or designed on a board | Designed in Circuit board | IR Supplier |
| Linearity | Non Linear | NTC’s are Non Linear | Linear | Linear | |
| Signal | mV | K Ohms | 100 / 1000 Ohms | Digital | |
| Accuracy | Fair | Fair | Good | Excellent | Fair |
| Extension Cable | 2 leads made of TC Extension Cable | 2 leads | 2, 3 or 4 leads | 3 Leads | |
| Notes | Cold Junction Compensation | Lead resistance can be significant | Non Contact Optical Sensor. |