gas purity analyzer according to the difference in thermal conductivity of gas ... with steady thermal conductivity value, such as air, N2, O2,CO2, etc. )CO20~100% (background gas is single ... gas with steady thermal conductivity value, such as air, N2, O2, H2, etc.)He70~100% (background gas is single gas ... , such as air, N2, O2, etc.)O295~100% (background gas is H2) Other two ...