digital thermometer wikipedia

This is placed under the patient’s tongue. This allows small changes in body temperature to be detected. Platinum is the most commonly used material because it is nearly linear over a wide range of temperatures, is very accurate, and has a fast response time. Sometimes thermometers with liquids are used, but not with mercury. Fahrenheit also created the temperature scale which is named after him, having recorded the system in 1724. The tip of the thermometer is inserted into the mouth under the tongue (oral or sub-lingual temperature), under the armpit (axillary temperature), into the rectum via the anus (rectal temperature), into the ear (tympanic temperature), or on the forehead (temporal temperature). The typical range of a sub-lingual thermometer for use in humans is from about 35 °C to 42 °C or 90 °F to 110 °F. If the patient has drunk a hot or cold liquid beforehand time must be allowed for the mouth temperature to return to its normal value.[14]. [1][2], Italian physician Santorio Santorio is the first known individual to have put a measurable scale on the thermoscope and wrote of it in 1625, though he possibly invented one as early as 1612. He accomplished this by using the ear canal's ear drum's blood vessels, which are shared with the hypothalamus. One needs to hold the thermometer for several minutes to get an accurate measurement. •Negative temperature coefficient (NTC) devices are used in temperature sensing and are the most common type of thermistor. Medically, a maximum thermometer is often used, which indicates the maximum temperature reached even after it is removed from the body. When the temperature falls, the column of liquid breaks at the constriction and cannot return to the bulb, thus remaining stationary in the tube. These typically reach equilibrium faster than mercury thermometers; the thermometer may beep when equilibrium has been reached, or the time may be specified in the manufacturer's documentation. This type may give an indication of fever, but is not considered accurate.[20]. Electron mobility in semiconductor is similarly influenced but more easily scaled and thus makes a better thermometer. As the temperature of the bulb rises, the liquid expands up the tube through the constriction. A medical/clinical mercury thermometer showing the temperature of 37.7 °C (99.9 °F), Encyclopædia Britannica "Science & Technology: Daniel Gabriel Fahrenheit", Fundamentals of Nursing by Barbara Kozier et al., 7th edition, p. 495, Ferdinando II de' Medici, Grand Duke of Tuscany, temperature scale which is named after him, "A Brief History of the Clinical Thermometer", "History of the Thermometer: Timeline created by TheArctech in Science and Technology", "782 - Aerodrome reports and forecasts: A user's handbook to the codes", "Dr. Theodor H. Benzinger, 94, Inventor of the Ear Thermometer", "Thermometry and interpretation of body temperature", "A prospective observational study testing liquid crystal phase change type thermometer placed on skin against oesophageal/pharyngeal placed thermometers in participants undergoing general anesthesia", "How to use the Tempa DOT Single Use Clinical Thermometer", Specification of typical inexpensive electronic ear thermometer, "An investigation into the accuracy of different types of thermometers",, Science and technology in the Dutch Republic, Short description is different from Wikidata, Creative Commons Attribution-ShareAlike License, This page was last edited on 23 October 2020, at 14:38. range of -55°C to +125°C and spec'd accurate to These thermometers are used both in the home and in medical facilities. It lacked an accurate scale with which to measure temperature and could be affected by changes in atmospheric pressure. Visibility is less of a problem with a coloured liquid. If a person drinks something hot or cold, one still needs to wait before testing their oral temperature. A thermometer is an instrument for measuring or showing temperature (how hot or cold something is). [25] The first electronic clinical thermometer, invented in 1954, used a flexible probe that contained a Carboloy thermistor. Another type is a digital thermometer, which … When a temperature is quoted the location should also be specified. Some electronic thermometers may work by contact (the electronic sensor is placed in the location where temperature is to be measured, and left long enough to reach equilibrium). Since compact and inexpensive methods of measuring and displaying temperature became available, electronic thermometers (often called digital, because they display numeric values) have been used.

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