S101 Diffusion O2 Sensor

The S101 Diffusion Oxygen Sensor measures oxygen concentration from 0-100% in a sealed chamber. Oxygen difuses to the sensor from surrounding atmosphere.  This sensor is the core of Qubit Systems’ PH1LP Teaching Photosynthesis Package.

S101 Diffusion Oxygen Sensor is a galvanic cell (a lead-oxygen battery) consisting of a lead anode, an O2 cathode, and an acid electrolyte. It also incorporates an O2-permeable Teflon FEP membrane with a gold electrode bonded to its surface. Oxygen diffusing through this membrane is reduced electrochemically at the gold electrode. The sensor can be fitted inside a sealed chamber for detection of O2 gas diffusing across the membrane.


A resistor and a thermistor (for temperature compensation) are connected between the anode and the cathode, so that the battery is always discharged. The output of the instrument is proportional to the current flowing through the resistor and thermistor and to the partial pressure of O2 in contact with the Teflon FEP membrane. The signal from the oxygen sensor is transmitted to the computer via the data acquisition interface and displayed in software as % O2.

  • Simple one point calibration requiring only atmospheric air
  • Output linear
  • 90% response in 12 seconds
  • Adjustable gain
  • Output range adjustable from 0 – 25% = 5 V
  • Temperature compensation
  • Expected sensor life is 3 to 5 years. Replacements are inexpensive.
  • Sensor is fitted with 1/8 inch Nylon NPT Union
    Oxygen Sensor.