Abstract: An apparatus for measuring fluid pressure has an electrical circuit for measuring fluid pressure which is closed only when simultaneously, the pressure to be measured is at least equal to a predetermined threshold and is substantially stable. A deformable member deforms under application of pressure of the fluid being measured and closes the electrical circuit. When fluid is moving through the apparatus, a Venturi valve member functions to lower the pressure of the fluid in contact with the deformable gauge member to reopen the electrical circuit. The Venturi valve member is formed by a revolution cone disposed in a chamber such that the passageway located annularly around the cone is reduced. A measuring apparatus integral with a deflating-inflating assembly is also provided.