Describes some experiments to examine the behaviour of relative humidity in sealed military electronic equipment exposed outdoors. The results have indicated that PCBs and other internal components feature very high 'desiccant capacity', although these items are not hygroscopic in the generally accepted sense of the word. Much of the moisture must be deposited on their surfaces which, especially with all the PCBs in position, represents a considerable area. Thus it can be quickly adsorbed and desorbed because, unlike truly hygroscopic materials, it is not necessary to wait for component temperature to rise significantly in order to vapourise their moisture. In such equipment the lag between a change in air temperature and a change in dew point is almost eliminated, the exchange of moisture taking place with very little delay so as to hold relative humidity stable throughout the diurnal cycle.
Temperature and humidity swings in sealed electronic equipment containers
Temperatur- und Feuchteschwankungen in geschlossenen Elektronikgeraetbehaeltern
Journal of the Society of Environmental Engineers ; 22 , 2 ; 7-10
1983
4 Seiten, 1 Quelle
Article (Journal)
English
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