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A thermometer is a temperature measuring device. Most methods use the temperature dependence of liquids and gases and determine the temperature from the coefficient of expansion. Corresponding methods are used in liquid thermometers. Other methods make use of the resistance changes of hot conductors and cold conductors

or those of metals and alloys. In addition to the method used, thermometers also differ in the type of temperature display, which can be analog or digital. Analogue indicating thermometers are usually liquid thermometers, where the extended liquid is fed into a thin glass tube attached to a scale. It is different with metallic detectors, whose resistance increases with temperature. In this method, which uses RTD elements, Resistance Temperature Detector (RTD), the change in resistance is detected by a current measurement, digitized in an AD converter and displayed on a digital display. In addition, there are also thermal sensors based on semiconductors

which generate an electrical voltage in the event of temperature changes by means of theSeebeck effect

. In addition to the above-mentioned methods, there are also thermometers which determine the temperature via the emitted wavelength. These are pyrometers. In terms of transmission technology, in addition to the classic direct-reading thermometers, there are also radio thermometers in which the thermosensor can be positioned at some distance from the receiving display.

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Englisch: thermometer
Updated at: 27.10.2020
#Words: 261