Application Note
In general, calibration means to measure accepted standards with the instrument to be calibrated, compare the obtained results with these reference values and re-adjust possible deviations.
For humidity calibration, saturated salt solutions are typically used. The addition of salt to an aqueous solution reduces the partial water vapor pressure above the solution compared to pure water.
In equilibrium with their environment, saturated salt solutions thus generate a defined salt- and temperature-dependent relative humidity which makes them suitable as a reference for humidity calibrations.
By selecting suitable salts, the entire calibration range can be covered in this way.
