Medical thermometer and displaying temperature became available, electronic thermometers (often called "digital", because they display numeric values) have been used. Many display readings to great precision (0.1 °C or 0.2 °F, sometimes half that), but this should not be taken as a guarantee of accuracy: specified accuracy must be checked in documentation and maintained by periodical recalibration. A typical inexpensive electronic ear thermometer for home use has a displayed resolution of 0.1 °C, but a stated accuracy within ±0.2 °C (±0.35 °F) when new. The first electronic clinical thermometer, invented in 1954, used a flexible probe that contained a Carboloy thermistor. Types
Reversing thermometer They are usually read to 0.01°C, and after the proper corrections have been applied, their readings are considered reliable to 0.02°C. Reversing thermometer Unlike most conventional mercury thermometers, a reversing thermometer is able to record a given temperature to be viewed at a later time. If the thermometer is flipped upside down, the current temperature will be shown until it is turned upright again. This was the primary device used by oceanographers to determine water temperatures below the surface of the ocean from around 1900 to 1970. It consists of a conventional bulb connected to a capillary in which a