Abstract: A pair of main electrodes are airtightly attached to their corresponding end openings of an insulating cylinder so that their discharge surfaces are opposed to each other with a gap between them in the insulating cylinder. An intermediate electrode is airtightly attached to the central portion of the insulating cylinder so that its discharge surface coaxially surrounds the space between the discharge surfaces of the main electrodes and faces the lateral faces of the main electrodes to define the discharge gaps. Electrode activators are contained in cavities or grooves in or on the main electrodes so as to be isolated from the discharge surfaces thereof, or are arranged on one of the respective discharge surfaces of the main and intermediate electrodes.

Abstract: A pair of main electrodes are hermetically mounted, by fusion of a low melting point metal, onto both end openings of an insulative cylindrical member, respectively. Main electric discharge surfaces of the electrodes oppose each other in said cylindrical member with a gap interposed therebetween. A recessed portion is provided in the main electric discharge surface of one of the pair of main electrodes. A pair of trigger electrodes are conductively connected to the pair of main electrodes, and oppose each other in the recessed portion to thereby form a trigger electric discharge gap therebetween. The pair of main electrodes are formed of electrically conductive material having a thermal coefficient of expansion greater than that of the insulative cylindrical member.

Abstract: A surge voltage arrester wherein a pair of main electrodes are respectively fitted in a gastight fashion to both open ends of a hollow cylindrical body formed of insulating material, wherein the discharge planes of the main electrodes are set opposite to each other in a hollow cylindrical body wherein at least one electrically conductive member extends along the inner wall of the hollow cylindrical body in its circumferential direction and faces one of the main electrodes at a prescribed interval, wherein at least one narrow electrically conductive strip electrically connected to the electrically conductive member extends along the inner wall of the hollow cylindrical body in its axial direction and faces the other of the main electrodes at a prescribed interval, and finally wherein at least one external electrically conductive member extends along the outer wall of the hollow cylindrical body which is capacitively coupled to the electrically conductive member extending along the inner wall of the hollow cyli

Abstract: An arrester holder apparatus having a cassette type insulating support which is detachably mounted in a distributor of a communication apparatus and has a plurality of openings staggered about the longitudinal axis thereof. A plurality of contact members are molded together with the cassette type insulating support such that one end of each of the contact members constitutes one contact portion which is in contact with a corresponding one of terminals of the distributor and such that the other end of each of the contact members constitutes the other contact portion which is exposed in a corresponding one of the openings at one side thereof. A ground member comprising a metal spring is mounted on the cassette type insulating support such that one end of the ground member has a plurality of contact pieces, each being exposed in the corresponding opening at the other side thereof and such that the other end of the ground member constitutes a common contact portion which is grounded.

Abstract: An overvoltage protecting element of the invention has a pair of main electrodes, the discharging surfaces of which oppose each other with a gap therebetween in a cylindrical body of an insulator, and a conductive member which is formed on the inner wall surface of the cylindrical body to oppose the main electrodes with a gap therebetween, and a plurality of extended parts of which extending in the circumferential direction of the cylindrical body being connected in the axial direction of the cylindrical body. The main electrodes and the conductive member are electrically connected to each other by capacitive coupling.

Abstract: An overvoltage protecting element comprises a hollow cylinder of an insulating material, a pair of electrodes sealed to the opposite ends of the cylinder, and a pair of conductive layers disposed on the inner wall of the cylinder so as to be located opposite to the respective electrodes and each having a projection which extends toward the electrode. The conductive layers are of the band type, and one or more projections are provided on a part thereof. In order to prevent deterioration of insulation resistance by repeated discharge, the conductive layers are provided at positions which are electrically insulated from the two main electrodes.