Home/Technical Glossary/K Type Thermocouple K Type Thermocouple A thermocouple is made up of of two dissimilar conductors in contact with one another, which produce a voltage when heated. Thermocouples are used as temperature sensors for measurement and control and can also be used to convert a temperature gradient into electricity. The Type K thermocouple (chromel -alumel) is the most commonly used general purpose thermocouple. It is inexpensive and a wide variety of probes are available in its −200 °C to +1350 °C / -330 °F to +2460 °F range. Sensitivity is approximately 41 µV/°C. Wire color standard is yellow (+) and red (-).