Three heating current intensities (I
¼ 12, 20 and 52 mA) are
considered for the same heating duration t
c
of 0.4 s (Fig. 3). The
behavior of the vacuum gauge is the same for the three cases but
the 12 mA curve gives the best performances above 10 Pa. At
saturation level, from 10
3
Pa to 10
5
h
Pa, a sensitivity frequency difference
is 250 mHz/Pa between the 12 mA curve and the 20 mA and
52 mAcurves. It was demonstrated that, when the current intensity
increases, the wires are no longer able to dissipate the heat
accumulated.