Thermistor- Thermistors are thermally sensitive resistors whose prime function is to exhibit a large, predictable and precise change in electrical resistance when subjected to a corresponding change in body temperature.[1] Negative Temperature Coefficient (NTC) thermistors exhibit a decrease in electrical resistance when subjected to an increase in body temperature and Positive Temperature Coefficient (PTC) thermistors exhibit an increase in electrical resistance when subjected to an increase in body temperature.[2]
In OpenBSD, many of the I2C temperature sensors from the below list have been supported and are accessible through the generalised hardware sensors framework[3] since OpenBSD 3.9 (2006),[4][5]: §6.1 which has also included an ad-hoc method of automatically scanning the I2C bus by default during system boot since 2006 as well.[6][5]: §5
In NetBSD, many of these I2C sensors are also supported and are accessible through the envsys framework,[7] although none are enabled by default outside of Open Firmware architectures like macppc,[8] and a manual configuration is required before first use on i386 or amd64.[5]: §7.1
Remote uncooled IR thermal radiometer sensors are also commonly used in integrated circuits.[9]