Gas detector sensor at low price
Catalytic diffusion sensors detect combustible gases and vapors by wounding wire into coils doped with catalysts. These coils are matched into pairs of reference and sensing elements, creating a combustible gas sensor. The sensor is connected to a Wheatstone bridge, which detects changes in resistance. When a combustible gas comes in contact with the sensor, the active element burns the gas, increasing its temperature. The reference element remains unchanged, indicating a positive combustible signal. The sensor must be intrinsically safe to prevent ignition in a combustible atmosphere. Electrochemical sensors consist of a working electrode, counter electrode, and reference electrode enclosed in a liquid electrolyte. Gas diffuses into the sensor, causing an electrochemical reaction, either oxidation or reduction. The electronics detect and amplify this current, displaying gas concentration in parts per million (PPM) for toxic gas sensors and percent volume for oxygen sensors.