®
Instruction Sheet
012-11736C
Oxygen Gas Sensor
PS-2126A
Introduction
The PS-2126A Oxygen Gas Sensor measures oxygen gas con-
centration in percent (%) and parts per million (ppm) oxygen.
It can be used to study plant, animal, or cellular respiration; air
quality; and the rate of oxygen (O
2
) production in chemical
reactions (see the experiment on page 2 for one example).
How it works:
The Oxygen Sensing Element is a galvanic fuel cell with a gas
permeable membrane at one end. It is very similar to a battery.
The fuel cell contains an electrolyte, anode and cathode. When
oxygen enters the fuel cell through the membrane, a chemical
reaction between the metallic cathode and anode and the elec-
trolyte occurs. This chemical reaction produces a voltage and
current that is present at the output jack at the other end of the
Oxygen Sensing Element. The current produced is propor-
tional to the concentration of oxygen present.
Oxygen Sensing Element Life:
Galvanic fuel cells have a limited lifetime which is determined
by their age and their exposure to oxygen. This is similar to
the life of a battery in a flashlight. If the flashlight frequently
used, the battery life will not be as long as it would have been
with limited usage. Similarly, the fuel cell’s useful life is
determined by its exposure to oxygen gas.
The fuel cell included with the PS-2126A has a useful life of
900,000 oxygen percent (O
2
%) hours.
An example: If the sensor is used in a 100% oxygen atmo-
sphere, the life of the sensor may be calculated as
900,000 O
2
% hours divided by 100% oxygen which is
9,000 hours. This is about 1 year.
The life of the sensor in normal air (20.9% oxygen) is
900,000 O
2
% hours divided by 20.9% oxygen which is
43,062 hours. This is about 4.9 years.
The sensor is guaranteed for a minimum of 2 years from the
date of manufacture. This is the absolute guarantee. If it is
used in a 100% oxygen atmosphere its life will be shortened.
If it is used in normal air, its life will be 4 to 5 years. There is
reported evidence of this particular sensing element being in
use for almost 10 years. In the end, the useful life of the sens-
ing element is dependent on the manner in which it is used.
Setup
Connect the Oxygen Gas Sensor to your PASPORT interface.
To prepare the Oxygen Sensing Element for use:
1.
Remove the Oxygen Sensing Element and deflector from
the packaging.
2.
Remove the pink tape from the Oxygen Sensing Element.
3.
Carefully thread the deflector onto the Oxygen Sensing
Element.
4.
Slide the rubber stopper over the deflector.
sensor amplifier
sampling
bottle
connecting cable
sensing
element
rubber stopper
Included Equipment
Part Number
Sensor Amplifier
PS-2126A (with
sensing element)
Oxygen Sensing Element (with deflector)
PS-6524
Rubber Stopper
Connecting Cable (3.5 millimeter)
Sampling Bottle
Required Equipment
PASPORT Interface and Software
See PASCO catalog
or www.pasco.com
