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
Beckmann thermometer Beckmann thermometer A Beckmann thermometer is a device used to measure small differences of temperature, but not absolute temperature values. It was invented by Ernst Otto Beckmann (1853 – 1923), a German chemist, for his measurements of colligative properties in 1905. Today its use has largely been superseded by electronic thermometers. A Beckmann thermometer's length is usually 40 – 50 cm. The temperature scale typically covers about 5 °C and it is divided into hundredths of a degree. With a magnifier it is possible to estimate temperature changes to 0.001 °C. The peculiarity of Beckmann's thermometer design is a reservoir