Carbon Monoxide Sensor p-type Metal Oxide Unlike common n-type sensors, this p-type sensor has a large dynamic range, repeatable response, low humidity response and resistance increases in the presence of CO. The change in resistance can be converted to an output voltage via a simple electrical circuit. Although the sensor can be used in constant temperature/ voltage mode, best response is achieved when the sensor is cycled between 400°C (sensing temperature) and 525°C (reset temperature). See our Application Note. PERFORMANCE Range Sensor resistance (Ro) Sensor resistance ratio (Rg/Ro x 100%) ppm CO limit of performance warranty kΩ (50%rh, 23 (± 2)0C) % CO @ 20ppm in air Gas response relationship (Rg/Ro - 1 = k.Conc) 5 - 50ppm Gas response relationship (Rg/Ro - 1 = k.Conc0.5) 50 - 500ppm Heater resistance (RH @ RT) Heater resistance (RH @ sensing temp.) Heater resistance (RH @ reset temp.) Heater power consumption (mW) typical for 5:1 Operating Temperature Range CROSS SENSITIVITY H2 sensitivity EtOH sensitivity C3H8 sensitivity NH3 sensitivity % measured gas @ 100 ppm H2 % measured gas @ 50 ppm EtOH % measured gas @ 500 ppm C3H8 % measured gas @ 25 ppm NH3 Figure 1 Response at low concentrations 1.6 Response from 8-50ppm CO, operating in 2temperature mode with a 5:1 cycle ratio of sensing (400 o C) and resetting (525oC). Response (Rg/Ro) Technical Specification This sensor works well in ambient conditions and also in extreme temperatures and humidities where electrochemical sensors cannot survive. This metal oxide gas sensor is equipped with a filter that allows CO selectivity. CO concentration (ppm) Alphasense Ltd, Sensor Technology House, 300 Avenue West, Skyline 120, Great Notley. CM77 7AA. UK Telephone: +44 (0) 1376 556 700 Fax: +44 (0) 1376 335 899 E-mail: [email protected] Websi

Carbon Monoxide Sensor p-type Metal Oxide Performance Data Figure 2 Real-time response at high CO concentrations 4 Real-time response data over range 100 - 500ppm CO in 50% rh air. Sensor operating in 2-temperature mode, pulsing between 5 mins at 400oC for 5 mins and 525oC for 1 min. Response (Rg/Ro) Time (minutes) Figure 3 Response from 10 to 500ppm CO 3.50 Response from range 8 500ppm CO operating in 2-temperature mode with a 5:1 cycle ratio of sensing (400 o C) and resetting (525 o C). Note linear behaviour <50ppm and power law behaviour >50ppm. Response (Rg/Ro) Figure 4 Response from 10%...