The thermometer is an instrument used to measure temperature. There are different types that function thanks to the expansion and pressure of bodies, whether liquid, solid or gaseous, or even thanks to the electronic variations noted. Depending on your needs such as measuring temperature ranges or the nature of the materials to be studied, your profession or the application of your thermometer, this operating principle may vary. In fact, you will need two kinds of measuring device if you want to take body temperature from a sick person or from an industrial oven. Whether your use is domestic or professional, you will find on the market three types of thermometer whose operation is different : the electronic thermometer, the liquid thermometer (mercury, alcohol or rapeseed) and the Galileo thermometer. Our temperature-taking specialists explains to you how do these thermometers work.
How the digital electronic thermometer works 📲
The electronic thermometer is probably the most widely used thermometer in the world. Very easy to use thanks to their probe and tips coupled with an LCD screen, they allow accurate and rapid temperature measurement. Some digital thermometers are also contactless (the infrared thermometers) and offer remote measurement. Their application is often professional, for example there are many medical thermometers or kitchen which are electronic; forehead thermometers, ear thermometers, thermometers with probe (outer, retractable, wired or removable) or with briefcase. Some high-performance devices used in particular in meteorology or in the scientific field also offer a recorder allowing you to compare complete data ranges, different units of measurement, monitoring and reading of data via an application, etc.
But let's see together more precisely how does an electronic/digital thermometer work.
The electronic thermometer is made up of 3 main elements. The sensor, the computer and the display.
It is the sensor which will measure the temperature and convert it into a signal measurable by the computer. For RTD probes (Pt100, Pt1000) and NTC and PTC thermistors, the resistance of the sensor changes depending on the temperature.
The computer therefore measures the resistance of the sensor to deduce a temperature in degrees Celsius or degrees Fahrenheit.
The display then retrieves this temperature information via an electrical signal and displays it in a way that humans can understand.
If your thermometer no longer transmits this data, it may be broken or even broken, do not hesitate to consult our article My thermometer is broken: what should I do?
How the alcohol thermometer works 🌡
The alcohol thermometer (which has the same effect as gallium or rapeseed oil) replaces the mercury thermometer known for its toxicity, which our grandparents' generation already used to measure body temperature or evaluate the ambient temperature of a room. room or refrigerator. THE how the alcohol thermometer works is simple: a glass tube held on a base graduated by degrees Celsius, is filled with alcohol and nitrogen. When the temperature rises, the alcohol expands, takes up more space and rises. When the temperature drops, the alcohol shrinks, takes up less space and goes down. The nitrogen exerts very slight pressure on the alcohol to hold it together. It is an accurate thermometer, however be careful not to place it in direct sunlight if you want to measure the outside temperature, as the temperature reading could be altered.
How Galileo's thermometer works ⚗️
The Galileo's thermometer has today become more of a household thermometer, sometimes even considered as a decorative object. You may be familiar with this elongated container containing glass ampoules filled with a colored liquid that move up and down. But then how does this thermometer work who hypnotizes us?
It is necessary to know that these glass ampoules do not contain just any liquids... Each of them has its own properties which, depending on the temperature, modify the density of the liquid and the flotation increases or decreases. Since each glass bulb has an assigned temperature, it is easy to determine the temperature. Galileo's thermometer is neither precise nor rapid, our measuring experts recommend that you only use it for decoration. 😉
Your professional thermometer
For learn more about the thermometer, you can consult our Guide complet on thermometers in which you will also find information such as our classification of thermometers by reliability, calibration or price ranges of thermometers for example.
Depending on your activity and therefore the thermometers you will need on a daily basis, their use will not be the same. To choose your professional thermometer, you must ask yourself the question “what is a thermometer used for?” this is what defines the perfect instrument for you. To go further, take directly an appointment with an advisor to choose your professional thermometer.
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