The gaseous sample can be ambient air, exhaust gases from an internal combustion engine, or exhaust gases from a combustion process. The burner jet is used as an electrode and is connected to the negative side of a precision power supply. The migration creates a small current between the electrodes. This current is measured by the precision electrometer amplifier and is directly proportional to the hydrocarbon concentration of the sample. The choice is switch selectable from the front panel or by remote contact closure.
Additional hardware includes a heated catalyst assembly and a three-way valve.