An arrangement of coaxial windings is provided. The arrangement includes primary and secondary windings as air-core pulse transformers having insulation and winding arrangement for efficient energy transfer to the secondary winding. The secondary winding is wound with a central metallic core to include a coaxial transmission line with it and is configured to deliver a rectangular pulse across its terminals. The arrangement also includes a coaxial feeding arrangement for the primary winding with a central coaxial terminal connecting to one end of an adjustable primary closing switch electrode so as to have variable voltage feed input corresponding to its load requirement.