What is Hair hygrometer
Hair hygrometer is the simplest and oldest type of hygrometer.It is made using hair as shown in figure
Human hair lengthens by 3 percent when the humidity changes from 0 to 100 percent, this property of hair can be used to operate a pointer or recording pen through a system of mechanical linkage.
The transducer element consists of strands of hair which arebgenerally arranged parallel to each other. It is not a precision instrument and not recommended where high degree of accuracy is required.
The change in length can be used to control a pointer for visual readings or a transducer such as linear variable differential transformers (LVDT) for an electrical output.
The hair hygrometer has an accuracy of about 5 percent for the humidity range 20 to 90 percent over the temperature range 5°C to 40°C.
Application of hair hygrometer:
Used where high precision is not required. These hydrometers are used in the temperature range of O'C to 75°C. These hydrometers are used in the range of relative humidity (relative humidity) from 30 to 95%
