When coil 3 is energized, it sets up a magnetic flux in magnetic
circuit 5 an d air gap a between magnet core 2 and diaphragm 1.
Upon a change in pressure in port 4, diaphragm 1 is bent upward
or downward, varying air gap a. This changes the resistance of
the m agnetic circuit an d, consequently, the magnetic flux, inducing
an emf in eoil 3 proportional to the rate of flux variation.
To o b ta in a q u a n tity at the o u tp u t of the instrument th at is
proportional to the pressure being measured, it is necessary
to employ an integrating and am p lify in g device.
$4392$SmE,M$