Model TC54

Measures the difference between the thermal transfer characteristics of the gas and a sealed reference. The typical carrier gas is nitrogen in gas chromatography. The sample and reference filaments are two legs of a Wheatstone Bridge. A constant current is applied with a resultant in a rise in filament temperature. As the sample passes through the detector, the resistance changes as the reference gas is replaced by the sample which has a lower thermal conductivity. This difference in resistance is proportional to the concentration. The response is universal since the detector responds to any compound that conducts heat. The minimum detection limit is in the 100-300 ppm. The maximum concentration is 100%.