An oxygen analyzer measures the para-magnetism of air. Para-magnetism is a form of magnetism in which material is attracted to a magnetic field and forms induced magnetic fields of their own as a result. The material itself will not continue to possess any magnetic properties once the influence of the initial magnetic field is removed.

In practical application, this means that oxygen is attracted to a magnetic field in certain ways. To talk about how this is measured, let’s use the most fundamental form of oxygen analyzer to understand the concepts behind it. Two chambers are used in an oxygen analyzer, both containing resistance wires. In one chamber, a magnetic field is created. In the other chamber, there is no magnetic field.

The air being measured for oxygen is filtered by passing it through a diffuser before. Then it is passed through the two chambers. One chamber attracts oxygen via its magnetic field, while the other chamber attracts air. Oxygen alone conducts heat differently than air, and so the temperature in each wire is different. The difference between the temperature of the two wires creates a resistance between the two legs of the circuit to which they’re part. This is known as a Wheatstone bridge circuit, and the resistance measured along this circuit is translated into a measurement of the oxygen content in the air being measured.

Of course, this is the foundation of understanding how oxygen analyzers make their measurements. Today, these measurements can be taken via infrared, ultrasonic, and even laser methods. Each offers particular strengths.

So whether you’re working on board a ship, in mines, in chemical storage areas, or in another industrial capacity, oxygen monitoring can save your life. It’s simple applied physics that can ensure the environment you’re stepping into is breathable and isn’t likely to spark a fire. Take a look at Michell Instruments’ series of oxygen analyzers for some of the best, most durable, and most flexible analyzers in the industry.