Title :
Simple rapid-response hygrometer
Author :
Gjessing, D.T. ; Holm, C. ; Lanes, T.
Author_Institution :
Norwegian Defence Research Establishment, Kjeller, Norway
fDate :
4/1/1967 12:00:00 AM
Abstract :
The instrument makes use of two simple crystal-controlled oscillators having nearly identical temperature/frequency characteristics. One of the quartz plates is covered with a very thin hygroscopic film and exposed to the atmosphere. The difference in frequency of the two oscillators is a function of humidity. Typical results are 6.5 Hz per % change in humidity at room temperature. The hygrometer resolves changes in humity down to 4/100%, the time constant of the sensor being better than 1/50s.
Keywords :
electric sensing devices; measurement by electrical methods; moisture measurement; nonelectric variables control;
Journal_Title :
Electronics Letters
DOI :
10.1049/el:19670122
