Gas flow measuring circuit and gas flow sensor

A gas flow measuring circuit comprising at least one reference resistor outside the gas flow and at least one variable resistor that varies in accordance with the characteristics of the flow of a gas and voltage measuring means for determination of a voltage difference between the at least one reference resistor and the at least one variable resistor, wherein the at least one reference resistor is arranged outside the gas flow and is at least by a factor of 10 less temperature sensitive than the at least one variable resistor, at least one current loop arrangement, the at least one current loop arrangement comprising a first current source coupled in series with the at least one reference resistor and a second current source coupled in series with the at least one variable resistor wherein both the at least one reference resistor and the at least one variable resistor are connected to ground for respectively providing an ideally constant and equal current through the at least one reference resistor and through the at least one variable resistor to produce first voltages across the at least one reference resistor and second voltages across the at least one variable resistor, and wherein the voltage measuring means is adapted to measure the voltage difference between the at least one reference resistor and the at least one variable resistor to produce a characteristic voltage difference representative of the characteristics of the gas.