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Alphasense 4-electrode sensors provide OEMs with low power, validated technology for use in high volume applications and evolving markets such as Air Quality monitoring.

Two parallel gas sensor families have been developed:

  • A4: small (20mm) but with good sensitivity and reproducibility.  Designed for mobile air quality networks where space is at a premium.
  • B4: same technology as the A4 but larger size (32mm). More robust when exposed to outdoor environments 24/7.  Designed for fixed site air quality networks which demand longer term reliability.

Strong, stable signal levels combined with low zero current and fast response make these sensors ideal for indoor air, urban air, outdoor and odour networks.  The A4 and B4 series of sensors offer our electrolyte leak-free guarantee and reliable long-term detection

With the introduction of these new 4-electrode sensors, together with our established portfolio of products such as PIDs for VOCs and NDIR for CO2, Alphasense now provides a complete solution for instrument manufacturers and systems developers.

We are an ISO 9001:2015 accredited company, providing 100% traceability on every Alphasense sensor shipped. No matter how small or large your usage, we can respond with fast kanban-based deliveries, on-time shipping and margin enhancing prices.

Note: all sensors are tested and stored at ambient environments unless otherwise stated. As applications of use are outside our control, all information provided is given without legal responsibility. Customers should test under their own conditions to ensure the sensors are suitable for their requirements.  Please use PCB sockets when connecting Alphasense sensors. Soldering, gluing or other methods of connection will void your warranty.



Staying at the forefront of sensor technology guarantees the best solutions for our customers



Each and every sensor is manufactured to the highest standards and tested for long-term reliability



Through investment and innovation we strive to exceed environmental and legislative targets


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