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4. How do the CGS500 sensors work?
The CGS500 sensors use a thermocatalytic priciple to detect combustible gases and vapours.
The sensing element consists of two coils of fine platinum wire coated in a catalyst to form beads.
One bead is the active bead and this bead will respond to gas concentrations. The other bead (the reference bead) is coated in a substance to render it non-reactive to gas.
An electric current is passed through both beads in series and this current raises the temperature of
the beads. Combustible gas or vapour oxidising on the surface of the active bead will further raise the temperature of the active bead and thus change the electrical resistance ofthe platinum wire.
The reference bead does not react to gas and is used to compensate for changes in external temperature, pressure, etc.