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
Frog thermometer Frog thermometer The frog thermometer or - as the Cimento academicians defined it, the "botticino" [small-toad] thermometer - contained small glass spheres of different density, which were immersed in alcohol. The device was used as a clinical thermometer, tied to the wrist or the arm of the patient with the head of the frog facing upward. The variations in body temperature were registered by the movement of the spheres. The rise in temperature causes an increase in the volume of the alcohol, reflected in the movement of the small spheres (first the less dense, then the more dense). Because of