Abstract: A surge arrester, includes a gas-filled housing, copper electrodes disposed opposite each other in the housing, the electrodes each including a relatively thin-walled truncated conical part having a flange integral therewith and a solid cylindrical part, the cylindrical parts each having a respective end surface facing each other, the end surfaces being mutually spaced apart by a given distance and each having a trough-shaped axially-symmetrical depression formed therein, a highly active electrode activating compound filling each of the depressions, a tubular ceramic insulator at least partly surrounding the electrodes defining respective annular gaps between the insulator and each of the cylindrical parts having widths being substantially between 0.2 mm and 0.

Abstract: Gas-discharge surge arrester having two axially opposing main electrodes defining a discharge gap therebetween and a middle electrode coaxially and annularly surrounding the discharge gap and connected to the main electrodes, respectively, by a tubular insulating housing, at least one strip of electrically conductive material disposed on the inner surface of the tubular housing and extending over a part of the length thereof, including respective transition members disposed at the ends of the tubular insulating housing, the transition members respectively forming a part of the main electrodes, the main electrodes being double-cylindrically formed into steps inwardly and forming a discharge path, the middle electrode being formed as a hollow cylinder having a conically profiled outlet and forming a respective main discharge path with both of the main electrodes, the main electrodes and the middle electrode being mutually overlapping at a region whereat they are provided with an electrode activating material.