Reliable Oxygen Detection for Safety and Performance

Alphasense oxygen sensors deliver reliable O₂ measurement for industrial safety, combustion analysis, and process control. The portfolio includes both lead-free (RoHS-compliant) and traditional lead-based galvanic sensors, giving OEMs a clear upgrade path as global regulations increasingly restrict lead use.
 

• Lead-free sensors (GLF and LFO2, A-Series) provide modern, RoHS-compliant designs, fast response, strong stability, and multi-year lifetimes — the preferred choice for new instruments and drop-in replacement for industry standard O2-A2 users.

• Lead-based sensors (O₂, A-Series) remain widely used in the global installed base due to proven performance and broad legacy compatibility, making them ideal for maintaining existing fleets.

Both technology families deliver multi-year lifetime, fast response, and stable electrochemical output that support portable multi-gas monitors, fixed systems, and compact wearables.

Sensor Portfolio Overview

Alphasense offers the market’s most complete O₂ portfolio, with clear segmentation between lead-free and lead-based technologies to simplify OEM selection.

Lead-free Oxygen Sensors (RoHS-compliant)

Available in both galvanic (GLF Series) and long-life amperometric (LFO2 Series) formats:

• O2-A2-GLF | O2-A2S-GLF — Lead-free galvanic, 2-year life, 2-pin zero-bias, drop-in A-Series size
• LFO2-A1 | LFO2-AL | LFO2-AH — Long-life, 5-year, 3-pin bias required, amperometric sensors for 0–30%, 0–95%, and 0–2% ranges respectively

These sensors deliver long lifetime, RoHS compliance, and robust stability across safety and process applications.

Lead-based Oxygen Sensors

Trusted and field-proven for existing global fleets.

• O2-A1 | O2-A2 | O2-A3 — Standard A-Series for portable and fixed monitors
• O2-G2 — Low-profile compact version for wearables
• O2-C2 — Rugged combustion variant with carbon-cloth filtering
• O2-A2S | O2-A3S | O2-A2Ni — Specialty A-Series tailored for unique integration. “-S” variants have no foam seal for custom sealing; “-Ni” sensors have nickel pins for soldering.

Lead-based sensors remain the industry standard for legacy monitors and international markets not yet transitioned to RoHS alternatives.

Mechanical Formats

• A-Series: Primary format for portable and fixed safety monitors (both lead-free and lead-based). O2-A2-GLF | O2-A2S-GLF | LFO2-A1 | LFO2-AL | LFO2-AH | O2-A1 | O2-A2 | O2-A3 | O2-A2S | O2-A3S | O2-A2Ni
• G-Series: Wearable low-profile lead-based option. O2-G2
• C-Series: Specialized combustion-gas lead-based variant. O2-C2

Choosing the Right O₂ Sensor

General Industrial Safety (Portable O₂ Monitors)

For worker-safety instruments requiring fast response, low power consumption, 2-pin zero-bias design, and compatibility with existing gas monitor architectures:

• Lead-free: O2-A2-GLF | O2-A2S-GLF
• Lead-based: O2-A2 | O2-A2S | O2-A3 | O2-A3S | O2-A2Ni

Long-life Fixed Installations & High-utilization Instrument Fleets

When minimizing service intervals and maximizing sensor longevity are the priority:

• Lead-free amperometric, 5Y life: LFO2-A1 | LFO2-AL (up to 95% O₂) | LFO2-AH (0-2% O₂)
• Lead-based galvanic, 3Y life: O2-A3 | O2-A3S 

Space-constrained / Wearable Devices

For compact personal monitors, where vertical height and device footprint matter:

• Lead-based: O2-G2 (low-profile design)

Key Benefits Across the Oxygen Sensor Portfolio

Alphasense oxygen sensors deliver dependable O₂ measurement across safety, combustion, and process applications — with clear advantages for both lead-free and lead-based formats.

Lead-free (GLF + LFO2 Series)

• RoHS-compliant designs ideal for all instruments
• Fast response, low drift and excellent long-term stability
• Multi-year lifetime options, up to 5 years
• Drop-in compatibility with GLF versions directly substituting lead-based versions for design-free transition from legacy sensors

Lead-based (A-Series, G-Series, C-Series)

• Proven global industry standard for worker-safety instrumentation
• Zero warm-up time and strong baseline stability
• Broad installed-base compatibility for fleet maintenance and legacy instrument support
• Specialized formats available (e.g. O2-G2 low-profile, O2-C2 combustion-gas filtered)

Portfolio-wide Benefits

• Reliable performance across extreme humidity and temperature conditions
• Stable electrochemical output for accurate oxygen measurement
• Multiple form factors to support portable, fixed and wearable devices

Why OEMs Choose Alphasense

Alphasense is a trusted global supplier of oxygen sensors because we consistently deliver:

• Batch-to-batch repeatability, ensuring predictable calibration and stable mass-production builds
• Long-term stability and low drift, reducing service intervals and lifecycle cost
• Decades of electrochemical expertise, with continuous innovation in lead-free and long-life technologies
• Robust technical support, application engineering guidance, and documentation
• Mechanical and electrical backward compatibility, allowing OEMs to upgrade to lead-free sensors without redesigning instruments
• High reliability in real-world conditions, validated across millions of deployed sensors in industrial safety environments

These advantages make Alphasense the preferred choice for OEMs building dependable oxygen-measurement solutions.

How Oxygen Sensors Work

Alphasense oxygen sensors use well-established electrochemical technology to convert ambient oxygen levels into a measurable electrical signal.

Galvanic (Lead-free GLF & Traditional Lead-based)

• Self-powered reaction between oxygen and the internal anode / cathode system
• Generates a current proportional to O₂ concentration
• No external bias needed and only 2 pins (2 electrodes) used
• Instant operation with zero warm-up time
• Ideal for portable safety devices and low-power instruments

Amperometric (Lead-free LFO2 Series)

• Uses a biased working electrode (3 pins) to measure oxygen reduction current
• Requires external power, but delivers:

• Extended operational life (up to 5 years)
• High stability and excellent precision
• Wide measurement ranges (0–30%, 0–95%, 0–2%)

2-pin vs. 3-pin

• 2-pin (no bias): Simple integration, low cost, no warm-up
• 3-pin (with bias): Long life and enhanced stability, requiring continuous power to avoid warm-up delays

This electrochemical architecture ensures accurate, reliable O₂ detection for safety and process control applications.

Why Measure Oxygen Gas

Accurate oxygen measurement is essential across a wide range of safety-critical and process-driven environments.

Worker Safety

• Low O₂ creates immediate life-threatening risks in confined spaces
• High O₂ increases fire and explosion potential
• Continuous monitoring protects workers across industrial, utility and municipal operations

Combustion & Process Control

• Combustion systems rely on precise O₂ levels for efficiency and emissions control
• Inerting systems require O₂ monitoring to prevent ignition risks
• Process optimisation and regulatory compliance depend on accurate oxygen measurement

Instrument Reliability & Fleet Performance

• Fleet managers rely on consistent, stable O₂ performance for portable multi-gas detectors
• OEMs benefit from predictable calibration behavior and long sensor lifetime

Oxygen is a foundational measurement in industrial safety — and selecting the right sensor ensures the accuracy, reliability and regulatory compliance required in these applications.