Pressure P is transmitted through th in m etallic membrane 1
to quartz wafers 2 clamped between plates. Steel b a ll 3 serves
for self-alignment of the device. Q uartz crystals are capable of
developing equal and opposite electric charges on certain elements
of their surfaces, proportional to the elastic mechanical
deformation to which they are subjected. The charges disappear
when the force load is removed. A single lead is connected to the
m iddle plate. The second conductor is the housing. The leads
are connected to an electrical measuring instrument.
$4357$,SmE,M$