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Digital Humidity Sensor HYT 939 – the specialist for compressed air


resitant to pressure up to 16 bar   | chemical resitant | autoclavable


The welded, hermetically sealed TO 39 housing with glass grommet and sinter filter is designed for compressed air systems up to 16 bar. Due to the humidity calibration process and the special polynomial correction method, a high accuracy is achieved specially in the lower humidity region up to 50 ppm water content, because of which the sensor is suitable for dew point measurements up to -40°C dp, for example, for the quality evaluation of medical compressed air.

Because of the specially robust construction, the sensor also withstands peak loading at high temperatures. Therefore, this special model is also ideal for extremely sophisticated industrial applications in drying systems and suitable for medical systems. 


Technical data

Model: Humidity sensor in TO39 housing, pressure resistant, with stainless steel sinter filter
Humidity ±1.8% rH, Temperature ±0.2 °C
Accuracy 0...10% rH (0 ... 50°C): ±(0.1% rH + 18% aw)
Measuring range: Humidity 0 ... 100% r.H. (max. dp = +80 °C), Temperature - 40 ... +125 °C
Dimensions: 5.2 x 9 mm
Connection: TO 39 Footprint

Humidity resolution: 0.02% rH
Hysteresis at 50% rH: < ±1% rH
Linearity error: < ±1% rH
Response time t63: < 10 sec (with stainless steel sinter filter)
Temperature resolution: 0.015 °C
Digital interface: I2C, address 0x28 or alternative address
Operating voltage: 2.7 … 5.5 V
Current consumption (Nom.): < 1?A in ready state < 22?A at 1Hz measuring rate 850 ?A maximum




see extended data sheet



HYT 939


Mikrosystem Assembly - close up


HYT LabKit 


By use of a USB cable the digital sensor can be attached to a PC. This Kit and software enables the graphical display of temperature, humidity, pressure, dew point as well as wet bulb temperature. 


Extended data sheet: Open pdf file 








ideal for:

  • high ambient pressure
  • pressure up to 16 bar
  • extreme conditions
  • high temperature fluctuation
  • measure pressure dew point
  • Online-Evaluation
  • Measuring of Gases
  • Vacuum Measurement
  • Measurement in over pressure
  • Measuring in protective athmospheres

optimal for:

  • Medical Technology
  • Autoclaves
  • Drying Technology
  • Plastic granules dryers
  • Laboratories
  • big compressed air systems
  • compressed air installations
  • chemical & pharmaceutical industry
  • food industrry
  • industrial applications