Pressure sensor, especially for intake air suction pressure

A pressure sensor, including a housing defining a movable pressure chamber which is connectable to a source of pressure to be measured, and further including transducer means for generating an electrical signal related to the magnitude of said pressure and wherein, according to the invention, said transducer means comprises a diffuse reflector (12) coupled to said movable chamber and a detector assembly (11) including a light source (13), a first light-sensitive detector (17) and a second light-sensitive detector (18) for detecting light reflected by said reflector (12) and further comprising regulator means for so controlling the electrical power of said light source (13) that the photo-current induced in at least one of said detectors (17,18) remains substantially constant independently of the prevailing distance (e) between said reflector (12) and said detector assembly (11).