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
- Measurements of photosynthesis in a sealed leaf chamber (integral component of the Teaching Photosynthesis Package PH1LP)
- Monitoring of O2 levels in a closed chamber
|Principle||Acid Electrolyte, Teflon Diffusion Membrane|
|Detection Range||0-25 %O2 (Linear) standard (can extend to 0-100%)|
|Accuracy||± 0.21% of Full Scale|
|Response Time (90%)||12 Seconds|
|Life Expectancy||4-5 years|
|Influence by Other Gases||Ammonia and Ozone|
|Required Sample Volume||Minimum of 2-3 mL/min|
|Operating Temperature||5 to 40oC (Effective range)|
|Compensation||Built-in Temperature Compensation|
|Pressure Range||0.5 atm to 1.5 atm|
|Pressure Effect||Output voltage changes proportionally|
|Shock Resistant||to 2.7 G|
|Vibration||Avoid strong vibration|
|Output||0-5 volt output|
|Power Supply||5 Volts (Provided by computer interface)|
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- Stephen Hunt. Measurements of photosynthesis and respiration in plants. Physiologia Plantarum Vol 117, Issue 3, p314–325 (2003).