Abstract: A transformer is configured to include a pair of cores that each have an inner leg, wherein a primary winding that is wound around a bobbin having a hollow into which the inner legs of the cores are inserted and that is hermetically sealed with resin material, and a secondary winding that has a hollow into which the inner legs of the cores are inserted and that is constituted of a conductor formed by die-cutting a metal plate into a ring are dispersedly arranged over the inner legs of the cores.

Abstract: Provided is flux composition for a solder, which thermally cures so as to cover and reinforce a solder ball during solder ball bonding. Employed is a flux for soldering, containing an epoxy resin, an organocarboxylic acid containing at least 0.1-40 mass % of a dicarboxylic acid having molecular weight of 180 or less, and a thixotropy-imparting agent, the epoxy resin and the organocarboxylic acid being blended such that there is 0.8-2.0 eq of the carboxyl groups of the organocarboxylic acid per 1.0 eq of the epoxy groups of the epoxy resin, and the epoxy resin, the organocarboxylic acid, and the thixotropy-imparting agent being contained in a total amount of 70 mass % or more relative to the total amount of the flux.

Abstract: A flux for resin cored solder containing a thermosetting resin is disclosed which is excellent in storage stability and productivity, and a resin cored solder having the flux built in. The flux for resin cored solder comprises a solid-state first flux containing a thermosetting resin, and a solid-state second flux containing a curing agent having redox activity, the first flux and the second flux being present in a non-contact state. A resin cored solder comprises the flux for resin cored solder and a lead-free solder alloy having a melting point ranging from 130° C. to 250° C. The resin cored solder is made up of a first resin cored solder in which the first flux is built into the lead-free solder alloy, and a second resin cored solder in which the second flux is built into the lead-free solder alloy.

Abstract: A soldering flux is disclosed which exhibits improved shape retention properties during printing, can inhibit sagging upon heating, and exhibits high electrical reliability between conductors. The soldering flux contains an epoxy resin, an organic carboxylic acid and, as a heat-resistant shape-retaining agent, and a plastic having a linear structure, wherein the epoxy resin and the organic carboxylic acid are blended so that the quantity of carboxyl groups in the organic carboxylic acid is 0.8 to 2.0 equivalents relative to 1.0 equivalent of epoxy groups in the epoxy resin, and the total quantity of the epoxy resin, the organic carboxylic acid and the plastic having a linear structure is 70 mass % or more relative to the total mass of the flux.

Abstract: An insulating member of the invention can include an epoxy resin, a first inorganic filler diffused in the epoxy resin and having an average particle diameter of 1 to 99 nm, and a second inorganic filler diffused in the epoxy resin and having an average particle diameter of 0.1 to 100 ?m. The first and second inorganic fillers can be independent of each other, and can be selected from a group including Al2O3, SiO2, BN, AIN, and Si3N4, and the blending ratios of the first and second inorganic fillers in the insulating member can be 0.1 to 7% by weight and 80 to 95% by weight respectively. A metal base substrate can be formed by forming a metal foil and a metal base on either surface of the insulating member.