Information about Relative Humidity

Relative humidity (r.h.) shows the relationship between absolute humidity (the amount really there) and the saturation state of water vapors. Relative air humidity is measured using humidity indicators, that show on their displays from 0% (absolutely dry air) up to 100% (air that is completely saturated, such as fog, clouds or steam bath). Some models of humidity indicators are an unlimited measurement range. The physical area is between 40 and 65% r.h. Given that hot air possesses the ability to absorb more water vapour than cold air, people feel that in winter, air is too dry and in summer it is too humid. If air heats up it increases the amount of water vapour to that of saturation. The consequence is that the % of relative humidity decreases while the real quantity of water remains constant. Something similar occurs when air is cooled, decreasing the quantity of water vapour. This increases the percentage value of relative humidity. Condensation forms when there is an excess of water in saturated conditions. Some of our humidity indicators offer the ability to not only measure relative humidity and temperature, but can also calculate dew point and dew point temperature. Dew point temperature is defined as the temperature at which the actual vapour content of air is the maximum (100% relative humidity). Dew point temperature is independent of the actual temperature. One possibility of dew point temperature is freezing metal until its surface forms condensation. The temperature of the metal will then be the dew point temperature. With this rain gauge you will be able to measure relative humidity which will be shown on the display.  

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PCE Instruments UK Limited
Units 12/13 Southpoint Business Park
Ensign Way, Southampton
United Kingdom, SO31 4RF
Phone. +44 ( 0 ) 2380 98703 0
Fax +44 ( 0 ) 2380 98703 0