The h.v. stage (12) is mounted on top of the current stage with a coupling element in-between. The voltage stage has an iron core with a centre limb that carries a coil (16) and is concentrically positioned w.r.t. a l.v. coil (17). The elements are concentrically located within a ringshaped ring-shaped screening electrode (18). The h.v. coil (16) is coveredby a metal screening element (20) of a high conductivity metal-Electrical wires (21) are brought out through an opening to external units. Conductors electrodes (22) connect (27) to form a low inductance path with the outer screening (18). The l.v. winding is also screened (25).
