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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

%) 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

% 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

% 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

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