pellistorbased
Pellistor-based sensors are gas detectors that rely on catalytic combustion on a heated bead, known as a pellistor, to sense flammable gases. In a typical arrangement the active bead is part of a Wheatstone bridge along with a matching reference bead. The catalytic bead is coated with a platinum or palladium catalyst and heated to several hundred degrees Celsius. When a combustible gas penetrates the protective coating, it oxidizes on the catalyst, releasing heat. The resulting temperature rise changes the bead’s electrical resistance, unbalancing the bridge and producing an electrical signal that is correlated to gas concentration, usually expressed as a percentage of the lower explosive limit (LEL).
Pellistor-based sensors are commonly used in fixed safety gas detectors and portable instruments in industries such
In practice, pellistor-based detectors are often paired with other sensor technologies to improve specificity and safety.