Abstract: An encapsulating case or box for hybrid circuits, able to operate in highly pressurized atmosphere, the components of the hybrid circuit being not subject to the action of pressure. For this purpose, said circuit is enclosed in a case taking the plane of the hybrid circuit substrate as the plane of symmetry, two half-shells made from an electrically insulating rigid material being arranged in symmetrical manner on the two faces of the substrate for creating a zero deformation area within the case. The electrical connections between the hybrid circuit and the connecting pins, outside the case and supported by the substrate are provided by flat metal conductors passing in the gluing plane to the substrate of a half-shell.

Abstract: A method of polymerizing a thermosetting resin such as an epoxy resin charged with silver particles in which shaped bodies of the resin are brought cold into contact with vapor of an organic liquid boiling at a temperature of above 100.degree. C. so that a condensate from this liquid forms on the bodies in temperature equilibrium so that the heat of vaporization is transferred upon such condensation rapidly to the bodies and the latter are polymerized rapidly under the constant temperature and pressure conditions.

Abstract: An electrical heating resistor of the type deposited on a substrate plate constituting the basis element of a thermal printing head. In order to concentrate the heat given off in the free surface of said heating resistor towards the paper to print, the invention provides for the deposition on the substrate of at least one layer having a relatively constant resistivity and then at least one surface layer with a non-linear resistivity and a negative temperature coefficient. Starting from a high value when cold, the resistance of the surface layer drops abruptly as soon as it reaches the triggering temperature, thus switching the heat resistor by command of a control circuit.

Abstract: The invention relates to microboxes for encapsulating electronic circuits.Electronic circuits frequently comprise decoupling capacitors or the like, which occupy a large amount of space compared with the integrated parts of the box. The invention provides for the use of the bottom or substrate of the encapsulating box as capacitors after metallizing the two faces. The dielectric material is matched to the desired capacitance values. The microbox substrate is formed by a multilayer capacitor for high values.

Abstract: A step adjustable attenuator comprising a silicon substrate on one face of which are deposited thin film-type resistors and electrical conductors by which the resistors are interconnected. Contact points are arranged at the periphery of the substrate and connected to the resistors. However, the attenuating sections are not interconnected on the substrate. A conductive pattern prepared from a conductive film forms finger-like leads of which inner portions are bonded to the contact points. By its shape, the pattern ensures the interconnections between the sections and forms two rows of outputs, one for the connections on the printed-circuit board on which is implanted the attenuator and the other being associated with displaceable straps enabling attenuation to be adjusted.