33 results about "Hygrometer" patented technology

A hygrometer is an instrument used to measure the amount of humidity and water vapour in the atmosphere, in soil, or in confined spaces. Humidity measurement instruments usually rely on measurements of some other quantity such as temperature, pressure, mass, a mechanical or electrical change in a substance as moisture is absorbed. By calibration and calculation, these measured quantities can lead to a measurement of humidity. Modern electronic devices use temperature of condensation (called the dew point), or changes in electrical capacitance or resistance to measure humidity differences. The first crude hygrometer was invented by the Italian Renaissance polymath Leonardo da Vinci in 1480 and a more modern version was created by Swiss polymath Johann Heinrich Lambert in 1755. Later in the year 1783, Swiss physicist and Geologist, Horace Bénédict de Saussure invented the first hygrometer using human hair to measure humidity.