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SNAA297–September 2016
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Copyright © 2016, Texas Instruments Incorporated
Humidity Sensor
Application Report
SNAA297–September 2016
Overview
CarmineIascone
ABSTRACT
Humidity affects many properties of air, and of materials in contact with air. Water vapor is the key agent
in both weather and climate, and it is an important atmospheric greenhouse gas. Humidity measurements
are used wherever there is a need to prevent condensation, corrosion, mold, warping or other spoilage of
products. This is highly relevant for foods, pharmaceuticals, chemicals, fuels, wood, paper, and many
other products. Air-conditioning systems in buildings often control humidity, and significant energy may go
into cooling the air to remove water vapour. Humidity measurements contribute both to achieving correct
environmental conditions and to minimising the energy cost of this.
Contents
1 Humidity....................................................................................................................... 2
2 Design Guide................................................................................................................. 2
2.1 Heat Conduction.................................................................................................... 3
2.2 Recommended Layout Implementation.......................................................................... 4
2.3 Self-Heating ......................................................................................................... 4
2.4 Air Flow .............................................................................................................. 4
List of Figures
1 Same Sensor Conditions and External Environmental Conditions Guarantee Good RH Measurements ....... 2
2 Example of Heating Sources in a Mobile Application................................................................... 3
3 PCB Layout Example ....................................................................................................... 4
4 PCB Layout Example........................................................................................................ 4
