Abstract: An ignition coil comprises a center magnetic core, a secondary coil wound on a secondary coil bobbin which is arranged at an outer side of said center magnetic core, a primary coil wound on a primary coil bobbin which is arranged at an outer side of said secondary coil. At least one of said secondary coil bobbin and said primary coil bobbin is formed by a, material which contains sulfur in a main chain of an aromatic class. The ignition coil has a superior anti-electric treeing. A coil component of the secondary coil and the primary coil of the ignition coil is arranged and accommodated in a coil case, an epoxy resin filling up at least melting silica is potted and is hardened. A development of the electric treeing can be restrained and the ignition coil having a superior endurance performance can be provided.

Abstract: An ignition coil comprises a center magnetic core, a secondary coil wound on a secondary coil bobbin which is arranged at an outer side of said center magnetic core, a primary coil wound on a primary coil bobbin which is arranged at an outer side of said secondary coil. At least one of said secondary coil bobbin and said primary coil bobbin is formed by a material which contains sulfur in a main chain of an aromatic class. The ignition coil has a superior anti-electric treeing. A coil component of the secondary coil and the primary coil of the ignition coil is arranged and accommodated in a coil case, an epoxy resin filling up at least melting silica is potted and is hardened. A development of the electric treeing can be restrained and the ignition coil having a superior endurance performance can be provided.

Abstract: An electrically insulated coil, characterized in that an electrical insulation layer wound around an electrical conductor is formed by laminating layers of glass flakes having a thickness of 0.2-1 .mu.m and a diameter of 40-250 .mu.m on a backing member of a sheet-like electrical insulation material and by impregnating with a semi-cured thermosetting resin. An electrically insulated coil is provided, having an excellent partial discharge resistance as well as having a high dielectric break down strength even when subjected to a large mechanical distortion.

Abstract: A fuel cell made up of a pile of unit cells, each consisting of a pair of cell element and separator packed in a cell frame, in which there are formed a fuel feed path and oxide product evacuation path in the piling direction. The cell frame is provided between its inner edge offsets and the outer edges of the cell element and separator with inner packings, and further provided near its outer edge on one side with an outer packing. The sealing structure perfectly prevents a fuel leak, and yet allows compactness and easy assembling process.