Honeywell CityTech 4 Series 4OXV CiticeL Oxygen Sensor Replacement AAY80-390 
Suitable for fixed-type detection

City’s 4 Series gas sensors are the industry standard for portable gas detectors. The range includes sensors which detect oxygen and toxic gases, an infrared version for carbon dioxide and hydrocarbons and fully certified pellistors for combustible gas detection.

Honeywell 4 Series includes sensors which detect oxygen and toxic gases and fully certified pellistors for combustible gas detection.

FEATURES

• Large robust toxic sensor design
• Comprehensive range for safety and emissions applications
• Suitable for fixed-type detection
• Robust and durable to environmental demands
  

Here's a basic explanation of how an electrochemical oxygen sensor works:

1. Electrochemical Cell: The sensor consists of an electrochemical cell that contains two electrodes separated by an electrolyte. One electrode is typically made of a porous material coated with a catalyst that promotes the reaction between oxygen and the material. The other electrode is usually made of a reference material.

2. Measurement Principle: When the oxygen-containing gas comes into contact with the sensor's electrode, a chemical reaction occurs on the electrode's surface. Oxygen molecules react with the catalyst, leading to the generation of ions in the electrolyte.

3. Ion Movement: The ions generated during the reaction move through the electrolyte between the two electrodes. This movement of ions creates an electric current that is proportional to the concentration of oxygen in the gas.

4. Output Signal: The electric current generated by the electrochemical cell is measured and converted into an output signal. This signal can be displayed as a voltage or current output, which can then be interpreted to determine the oxygen concentration in the gas being measured.

5. Calibration and Compensation: Oxygen sensors often require calibration to ensure accurate measurements. This calibration involves exposing the sensor to known oxygen concentrations to establish a relationship between the sensor's output signal and the actual oxygen concentration. Additionally, temperature and other environmental factors might influence the sensor's performance, so compensation techniques are used to account for these effects.