A pick-up for the intake pressure of a combustion engine of the type with a flexible membrane and electrical translation of the displacement of the membrane, including a spring acting against the member, an adjustment mechanism for positioning the spring acting against the membrane, a guiding tube for the spring serving as a stop for the membrane, a closed magnetic casing made of ferrite including nested cylinders pierced by a hole at each end of their axes, a central ferrite magnetic core connected to the membrane and penetrating the closed magnetic casing, an insulating bobbin disposed within the casing, a single winding placed on the insulating bobbin around the core and covering a major portion of the core in its deepest position, the bobbin further including cylindrical ends extending beyond the magnetic casing on opposite sides thereof so as to form an air pocket between the core and the casing and guide the core in the casing, and an oscillating electronic circuit connected to the winding which includes a variable pressure/frequency translator.