Therefore, each frequency measurement f corresponds to a
pressure P of the fluid (air) given by the reference Pirani gauge in
the range 0.1 Pae10
5
1
, diameter d ¼ 25.4 mm,
t
h
¼ 1s,t
DU ¼ U
sup
c
¼ 1.25 s, I
U
inf
c
¼ 31.5 mA, oscillation frequency f ¼ 1/(t
¼ 5.2 mV, DT ¼ T
sup
T
inf
¼ 104
c
þ t
h
C. The dashed curve (.......) corresponds
to the rise in temperature that would follow the thermocouple if the amplified
voltage (1000) measurement was possible during the heating duration t
Pa.