Abstract: A triggerable switching spark gap has two main electrodes, which are insulated from each other, and a galvanically controllable trigger electrode, which is configured in the center of a circular opening of one main electrode. A clearance (a) between the two main electrodes is greater by the factor 1.1 to 2.3, preferably by the factor 1.4 to 1.7, than the width (b) of the ring gap between the trigger electrode and the corresponding main electrode. Furthermore, the circumferential edge of the trigger electrode (6) arranged to be flush with the discharge surface of the corresponding main electrode has a radius of curvature less than or equal to 0.1 mm and the trigger electrode and the corresponding main electrode are coated with a silver-containing activating mass. The delay time of the switching spark gap is able to be reduced to values less than or equal to 0.5 .mu.s.

Abstract: In order to ensure that the ignition voltage does not depend on whether a sark gap component is shielded or unshielded, a ring-shaped control electrode that makes electrical contact with the electrode not at ground potential is mounted adjacent to or on to the outer circumference of the insulator at an axial level almost equal to that of the active surface of the electrode not at ground potential. The control electrode comprises of either a metallic coating, a band-shaped strip, or a metal cap.