An O2 sensor typically operates based on electrochemical principles. The sensor consists of two electrodes (an anode and a cathode) immersed in an electrolyte. When oxygen comes in contact with the sensor, it undergoes a chemical reaction, producing a small current proportional to the oxygen concentration. This current is measured, interpreted, and displayed as an oxygen concentration percentage. The sensor can provide real-time oxygen readings, allowing timely detection of any deviations from normal levels (20.9% in ambient air).

Specifications

1. Measuring Range

• Standard Range: 0–25% Vol (volume)
• Extended Range (for specialized applications): 0–100% Vol

2. Resolution

• Typically 0.1% Vol for standard applications
• Higher precision applications may require 0.01% Vol resolution

3. Accuracy

• ±0.1% to ±0.2% Vol, depending on environmental conditions and calibration

4. Response Time (T90)

• Typically 10–15 seconds (time to reach 90% of the final reading)

5. Operating Temperature Range

• Commonly -20°C to +50°C
• Extended temperature models available for harsher environments, e.g., -40°C to +60°C

6. Operating Humidity Range

• 15–90% RH (non-condensing) for most models
• Extended humidity models available for high-humidity environments

7. Operating Life

• Average lifespan of 2–3 years under normal operating conditions
• Some advanced models offer up to 5 years, depending on the application

8. Output Signal

• Analog output (e.g., mV or mA) proportional to oxygen concentration
• Digital output (e.g., I2C, UART) in newer models for direct interfacing with microcontrollers

9. Power Consumption

• Typically low power (< 0.5W), allowing for battery operation in portable gas detectors

10. Cross-Sensitivity

• Designed to minimize cross-sensitivity to other gases; however, high concentrations of gases like CO2 may affect accuracy in some models.

11. Environmental Compatibility

• Resistant to common contaminants in industrial settings, such as dust, water vapor, and temperature fluctuations.

Optional Features

1. Self-diagnostic and Auto-calibration Capabilities: Some models have self-diagnostic functions to detect sensor health and auto-calibrate for accuracy.
2. Built-in Alarms: Configurable alarms when oxygen levels fall below safe thresholds (e.g., <19.5%).
3. Wireless Connectivity: Some advanced models support Bluetooth or Wi-Fi for remote monitoring and data logging.

Applications

O2 sensors are used in a variety of settings, including:

• Confined spaces
• Industrial safety monitoring
• HVAC systems
• Environmental monitoring