caused by burning or catalytic oxidation of surrounding material to be tested, e.g. of gas

Full Title

Investigating or analysing materials by the use of electric, electrochemical, or magnetic means (G01N3/00 – G01N25/00 take precedence; measurement or testing of electric or magnetic variables or of electric or magnetic properties of materials G01R) > by investigating impedance > by investigating resistance > of an electrically-heated body in dependence upon change of temperature > caused by burning or catalytic oxidation of surrounding material to be tested, e.g. of gas