A solid electrolytic capacitor including a first electrode having formed an oxide film on its outer surface, a second electrode disposed opposite to the first electrode and a solid electrolyte composed substantially of granular manganese dioxide of gamma type and disposed in contact and between the first and second electrodes. The solid electrolyte has a high film-forming ability and is prepared by electrolyzing manganese sulfate dissolved in an aqueous solution of sulfuric acid. The solid electrolytic capacitor is capable of operating stably over a broad temperature range and for a prolonged period of time even when it is placed on use at a high-operating temperature.
A gas detecting device formed of a porous, highly permeable, metal oxide semiconductor formed by mixing semiconductor particles with inorganic materials which will render the semiconductor highly porous or by intermixing the semiconductor with materials which can be evaporated or otherwise removed by heating to a temperature below the sintering temperature of the semiconductor. The resultant semiconductor material is contained within a suitable housing that will permit gases to flow readily through the semiconductor and appropriate electrodes are affixed to the semiconductor to measure a change in resistance in the presence of reducing gases. Heating means may be utilized to stabilize the resistance of the semiconductor material during operation and such heating means may comprise at least one of the electrodes.
In order to accommodate increasing operation speed of a digital circuit, a distributed constant type noise filter having a low impedance transmission line optimal to provide a power de-coupling of an LSI operating at high speed is provided. Particularly, a capacitor-forming portion of the distributed constant type noise filter is constructed with a solid electrolytic capacitor having a 3-terminal structure. In the distributed constant type noise filter constructed as mentioned, a ratio of width W of the capacitor-forming portion to thickness d of a dielectric member thereof and length L of the capacitor-forming portion are set on the basis of dielectric constant of the capacitor-forming portion such that electric noise generated by an electron device connected thereto are removed over a wide frequency range thereof.
A process of making a capacitor element for a solid electrolytic capacitor is provided which comprises the steps of preparing at least one capacitor piece which includes a chip of a sintered mass of metal powder and an anode wire projecting from the chip, forming a dielectric layer on the chip, forming a solid electrolyte layer on the chip, forming a metal layer on the chip, and cutting the metal wire at a position spaced from the chip. A water-repellent member is fitted on the anode wire and located close to the chip at least up to finishing the step of forming the solid electrolyte layer. Further, the water-repellent member is shifted along the anode wire away from the chip at least before cutting the anode wire, whereas the anode wire is cut at a position between the chip and the shifted water-repellent member.
In a solid electrolyte capacitor, a metallic cathode collector layer is in direct contact with an electrolyte layer which is formed of densely accumulated manganese dioxide particles of 0.1 - 50 .mu.m. The manganese dioxide layer is formed by performing pyrolysis of manganese nitrate in a semi-closed heating chamber of a radiant furnace to offer a resistance to the outflow from the chamber of gaseous decomposition products. The collector layer is formed by spraying, preferably by plasma spraying, of a metal powder typified by copper powder.
A solid electrolytic capacitor comprising a capacitor element which includes a valve metal member capable of forming a dielectric oxide film thereon, a dielectric oxide film formed on the valve metal member, a manganese oxide layer formed on the dielectric oxide film, a conductive polymer film formed on the manganese oxide film by electrolytic polymerization, and terminals formed on the valve metal member and the conductive polymer film, respectively. The solid electrolytic capacitor is improved in capacitor characteristics. A method for manufacturing the solid electrolyte is also described wherein the conductive polymer film is readily formed on the manganese dioxide layer.
