GAS DISCHARGE TUBE

摘要

A gas discharge tube (10) for producing a discharge between an anode portion (24) and a cathode portion (52) which are disposed in a hermetic container (12) within which a gas is sealed is disclosed. The gas discharge tube (10) comprises a tubular discharge channel restricting portion (28), which is arranged between the anode portion and the cathode portion and has a through hole (46) for narrowing the discharge channel between the anode portion and the cathode portion, and an insulative discharge channel restricting portion supporting portion (30) for supporting the discharge channel restricting portion. One end of the discharge channel restricting portion has a cylindrical projecting portion (44) which protrudes toward the cathode portion, and the outer diameter (D) and the height (H) of the projecting portion (44) are set to have a ratio (D/H) of 0.5-2.0. With this structure, a strong electric field can be generated in the vicinity of the end of the projecting portion, thereby lowering the starting voltage and surely producing a discharge.