Abstract: A technology capable of setting a leakage inductance to a predetermined value and enabling miniaturization is provided. In a transformer including a primary coil and a secondary coil which are coaxially provided, the primary coil includes a first primary coil portion and a second primary coil portion in series, the secondary coil includes a first secondary coil portion and a second secondary coil portion in series, the second primary coil portion and the second secondary coil portion are provided outside the first primary coil portion and the first secondary coil portion, and a degree of coupling between the second primary coil portion and the second secondary coil portion is set to be lower than a degree of coupling between the first primary coil portion and the first secondary coil portion.

Abstract: A technology capable of setting a leakage inductance to a predetermined value and enabling miniaturization is provided. In a transformer including a primary coil and a secondary coil which are coaxially provided, the primary coil includes a first primary coil portion and a second primary coil portion in series, the secondary coil includes a first secondary coil portion and a second secondary coil portion in series, the second primary coil portion and the second secondary coil portion are provided outside the first primary coil portion and the first secondary coil portion, and a degree of coupling between the second primary coil portion and the second secondary coil portion is set to be lower than a degree of coupling between the first primary coil portion and the first secondary coil portion.

Abstract: A tube fitting assembly is provided in which the back sleeve 4 can be simply fabricated without any reduction in its corrosion resistance. The back sleeve 4 is fabricated by pressing the exterior edge of the front end of a short column with a roller 6 of greater hardness than the short column whereby a tapered face 42 is formed on the outer edge of the front end that is harder than the rest of the piece. A bore or cavity is then bored axially through the short column. Thereafter, the back sleeve 4 so formed can be assembled with the tube to be connected, the coupling body 2, the front sleeve 3, and the envelope nut 5 to form an effective tube fitting assembly.