Abstract: A deformable pressure chamber (10) moves a permanent magnet (12) carried by it as it is deformed. A GaAs Hall element (13) is disposed on a substrate plate (1) opposite the permanent magnet, and the substrate plate also carries a hybrid circuit including a temperature compensating network of thick film resistors and an amplifier. The Hall element is subject to only small temperature effects, and these are compensated in a circuit that can work with a low supply voltage.

Abstract: A meander-shaped layer of nickel is deposited by evaporation on a ceramic wafer over an intermediate layer of tantalum serving to improve adhesion, and covered by a protective coating of silicon or epoxy resin is used as a temperature sensor in the intake pipe of a supercharged internal combustion engine. The low mass of the sensor element thus provided enables the resistance of the nickel path to follow rapidly, by its variation, the variations of temperature of the intake air. The sensor has a casing made up of two parts, the lower one of which has two connection prongs molded into it, the ends of which are flattened into tabs that are soldered to contact areas of the ceramic wafer. The upper casing portion has a cavity for the ceramic wafer, the lower part of which is filled with a potting compound to protect the solder joints. The width of the nickel paths that provide the temperature sensitive resistance is about 50 .mu.m and the thickness is from 0.2 to 1 .mu.

Abstract: Two permanent magnets at an adjustably fixed distance from each other face each other with like poles and are mounted on the moveable portion of a pressure-sensitive membrane, with one magnet near the membrane, and the other one at some distance away, while a Hall-effect sensor of fixed position is located between the magnets. The null point of the output scale and the scope of the transducer characteristic can be set either by adjusting the position of the magnets or by adjusting the amount of their magnetization.

Abstract: The interior of a differential pressure cell is exposed to the pressure in the intake pipe of an internal combustion engine. An absolute pressure cell is exposed to the ambient air pressure. The movable membrane of the differential pressure cell carries a plate on which are mounted two permanent magnets whose North poles face one another. A Hall generator fastened to the center of the movable membrane of the absolute pressure cell moves in the gap between the two magnets. The effective magnetic field applied to the Hall generator thus varies with the relative position of the Hall generator and the magnets. Adjustment of the spring constants of the two membranes allows any linear combination of differential and absolute pressure to be formed. Embodiments of different complexity and different degrees of linearity are illustrated.

Abstract: A corrugated membrane cavity has a flexible membrane, the center of which, in response to changes of pressure, varies of spacing between a magnet, for example carried on the membrane, and a Hall generator integrated circuit, in which the Hall generator is mounted coaxially with the polarity axis of the magnet and the flexible membrane. Another magnet on the other side of the Hall-IC faces the first magnet, so that like poles are facing each other, and so that the Hall-IC operates in a region of the induction field that is symmetrical with respect to the plane of zero induction that exists midway between the magnet. This working range makes possible a relatively high and linear variation of output voltge of the Hall-IC in response to variation of the magnetic induction which is particularly useful for pressure sensors for installation in the air intake duct of a motor vehicle engine.

Abstract: An electromechanical transducer for transforming pressure fluctuations into varying electrical signals, especially for use as the induction tube pressure sensor for an internal combustion engine. A Hall-effect sensor moves within a local magnetic field to detect changes in pressure which alter the configuration of a diaphragm or diaphragm bellows to which the Hall-generator is attached. In order to suppress temperature-dependent terms in the Hall voltage equation, the invention provides for periodically alternating energization of the electromagnets, i.e., for alternation or alternating shut-off of the magnetic field. The Hall voltages measured during the two states of the magnetic field are subtracted from one another, thereby eliminating the temperature-dependent term. A number of configurations of the transducer elements is presented.

Abstract: A Hall-effect sensor unit producing an electrical output is located between two permanent magnets of opposed polarity. The magnetic induction detected by the sensor unit is caused to vary with the pressure by variation of the spacing between the sensor unit and one or both magnets, or by variable introduction of a magnetically soft member between the sensor unit and one of the magnets, the motion being produced in each case by a membrane or a variable volume chamber which produces displacement in proportion to gas pressure to be sensed. The force converter is particularly designed to provide a highly linear pressure measurement signal for the air intake condition of an internal combustion engine.

Abstract: To measure small displacements, for example displacement of a membrane under change of pneumatic pressure applied at opposite sides thereto, a ferromagnetic wire is stretched between a fixed support and the membrane. An exciter coil, connected to a source of alternating current of suitable strength cyclically reversely magnetizes the ferromagnetic wire. A pick-up coil is electromagnetically coupled to the wire to sense the change of magnetization thereof which will be in the form of sharp needle pulses as the magnetization of the wire changes, the pulse amplitude and pulse width being highly dependent on the strain in the wire and hence on the deflection of the membrane. The wire may be stressed under tension.