Measuring
gas containing oxygen is blown through a tutoridal
chamber with a filament heated cross connection. The toroidal
chamber is matched between the poles of a permanent magnet in such a
way that one half of the filament only is placed between the magnetic
poles. The filaments winding has a center tap. The two half's build
together with two additional resistors a Wheatstone bridge.
A gas flow through the toroidal chamber
is divided uniform in the two half's
Oxygen atoms included in the measuring
gas are pulled into the cross
connection by the magnetic field. Here they are heated up by the
filament till the Curie-temperature is exceeded and they become
diamagnetic. Following the oxygen atoms are pushed out of the magnetic.
Because of this process one half of the filament (Resistor R2) heats up
more and becomes higher resistance, changing thereby the detector
voltage in the Wheatstone bridge.
