The 1220 Humidity Generation System is a self-contained system capable of producing atmospheres of known humidity using the fundamental “two-pressure” principle. This system is capable of continuously supplying relative humidity, dew point, frost point, parts per million, or other calculated values for instrument calibration and evaluation as well as for precision environmental testing. This system will automatically generate manually entered humidity and temperature set points as well as user created multipoint profiles. All desired humidity’s, temperatures, flow rates, and time intervals may be programmed. The 1220 humidity generating system incorporates a test chamber, with internal dimensions of 8” x 8” x 8”. Test chamber pressure range is ambient. Access is available through one 1.875” diameter port located on the right side, for probes, cables, sample tubes. The test chamber accommodates various solid-state sensors, sensing systems, chilled-mirror hygrometers, as well as material samples for environmental testing. Virtually any humidity and temperature may be generated, for long periods of time, within the operational limits of the generator. The output or recording of the device under test may then be compared with the generator’s data for analysis.