GB1278972A - Switching device - Google Patents

Abstract

1278972 Cold-cathode tubes HUGHES AIRCRAFT CO 27 Oct 1969 [27 Nov 1968] 52418/69 Heading H1D A switching device comprises an envelope 30 containing an anode 46 and a cathode 40 one of which is perforated, an electromagnet 58 to produce a magnetic field in the space between the anode and cathode and a gas space on the side of the perforated electrode away from the other electrode of greater volume than the space between the anode and cathode. A high power D.C. switch filled with hydrogen or deuterium at 0À04 mm. Hg comprises a cylindrical stainless steel cathode 40 with an axial slot to prevent circular currents and a perforated anode 46 mounted from opposite ends of the envelope. The electromagnet 58 provides a field increasing the mean free electron path sufficiently to cause ionization and a flow of arc current. When current flows gas ions become implanted and adsorbed on the cathode resulting in a slow fall in gas pressure which eventually causes the current to cease. By providing the gas space within the anode communicating with the interelectrode space, the fall is reduced and cut-out is delayed. A titanium hydride ribbon or sponge 60 provides an auxiliary gas source. The cathode may be withdrawn by removing a base flange 34.