2. An appliance used for maintaining the vapor pressure in the air of a room or other enclosed space within set limits.
2. A device used for regulating the relative humidity of an enclosed space.
A hygrostat contains a sensor that detects a preset level of humidity and is connected to a heater that is turned off, and on, as needed in order to keep the humidity at the preset level.
Hygrostats are used in humidifiers, and dehumidifiers, and are placed in the ductwork of laboratories and other facilities where climate control is necessary.
2. A humidistat (instrument for measuring humidity) in which a change in the relative humidity causes a change in the electrical resistance between two sets of alternate metal conductors mounted on a small flat plate with plastic coating, and this change in resistance is measured by a relay amplifier.