This sensor can be used to make measurements of the level of free-oxygen in air or dissolved oxygen in water. The free-oxygen in air mode is used to measure changes in oxygen levels during combustion or in reactions that produce oxygen (hydrogen peroxide decomposition). The Dissolvedoxygen mode is useful in the study of photosynthesis. The oxygen sensor is designed for use both in the school laboratory and in the field. It employs easy-to-use polarographic (Clark) technology and replaceable membranes are available for it. The electrode itself is constructed of Delrin® for durability. With its integral thermistor, it provides dependable temperature-compensated measurements. The thermistor is housed in stainless steel and sealed on the electrode's outer
wall providing fast, accurate readings.
The sensor should be connected to a voltage source (the USB module plugged into a computer, Edu-Logger's™ Display unit or Battery module). For free Oxygen, calibration of the probe is simply achieved in open air, taking this as a standard level of 20.9% (assuming stable level in the Earth's atmosphere at sea-level) and pressing the push-button on the sensor's box for about 3 seconds when the readings are stable. The sensor will then be calibrated at 20.9%. In liquid, the sensor is calibrated to 100% in an Oxygen saturated solution.
Some datalogging O2 sensors require both zero-oxygen solution and 100% calibration bottle since their sensors are not factory calibrated. The Edu-Logger sensor is, so they do not need both points (0 and 100%) and therefore there is no need for the zero-oxygen solution. For a 100% point setting we recommend the use of a 50 ml plastic syringe to pump air into the water and set the 100% saturation point.
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