A pulse transformer connects a capacitor to an ignition means. A secondary coil housing is a tubular shaped member molded about a core leg carrying a flat wound primary coil. An axially extended coaxial recess receives a multi-turn single layer secondary coil wound on a support tube. The recess is filled with a suitable potting material and a U-shaped core assembly is secured to the center core leg to define a closed rectangular path. A high voltage connector is connected to the innermost turn of the secondary coil with a minimum spacing therebetween.