A gas switch includes an anode and a cathode spaced apart from the anode, wherein the cathode includes a conduction surface. The gas switch also includes a plurality of magnets arranged to generate a magnetic field that defines an annular path over a portion of the conduction surface at a radial distance from a switch axis, and a control grid positioned between the anode and the cathode. In operation, the control grid is arranged to establish a conducting plasma between the anode and the cathode, wherein, in the presence of the conducting plasma, a voltage drop between the anode and the cathode is less than 150 volts, and wherein the conducting plasma forms a cathode spot that circles the annular path.

A gas switch includes an anode and a cathode spaced apart from the anode, wherein the cathode includes a conduction surface. The gas switch also includes a plurality of magnets arranged to generate a magnetic field that defines an annular path over a portion of the conduction surface at a radial distance from a switch axis, and a control grid positioned between the anode and the cathode. In operation, the control grid is arranged to establish a conducting plasma between the anode and the cathode, wherein, in the presence of the conducting plasma, a voltage drop between the anode and the cathode is less than 150 volts, and wherein the conducting plasma forms a cathode spot that circles the annular path.

A starting aid for discharge lamp arc tubes is characterized by an arc tube having a tubular body wall that longitudinally extends between first and second ends and surrounding an internal arc cavity with first and second electrodes that have conductive feedthroughs to electrically connect to corresponding first and second external arctube leads; an antenna conductor extending longitudinally on an outside surface of the arc tube wall between first and second antenna ends that are located radially outward of corresponding first and second electrodes; and an antenna coupling member comprising a conductive coupling connector that is electrically connected to the first arctube lead, and extends to a coupling end located on the body wall near to the first antenna end and separated from it by a coupling gap of predetermined, non-zero gap dimension.

A flash discharge tube includes tungsten pins configuring a pair of discharge electrodes, and an envelope. The envelope includes a central region, serving as an alkali-free region, which is configured with an alkali-free glass except for quartz glass. The central region becomes in a high temperature state during a firing operation of the flash discharge tube. The central region is smaller than a maximum region enclosing a gas-tight space formed by hermetically sealing the pair of the discharge electrodes and is not smaller than a minimum region enclosing an arc-discharge space formed between the tungsten pins of the pair of the discharge electrodes. The alkali-free region contains either no alkali metal component or not larger than a predetermined amount of an alkali metal component. Then, a trigger electrode is disposed in the alkali-free region. This provides the flash discharge tube featuring a stable short-interval continuous-firing operation.

There is provided a vacuum switching assembly for switching an AC or DC current. The vacuum switching assembly comprises a vacuum switch. The vacuum switch includes: first and second electrodes (20, 22) located in a vacuum tight enclosure, the vacuum tight enclosure containing a gas or gas mixture, the first and second electrodes (20, 22) defining opposed electrodes being separated by a gap, each of the first and second electrodes (20,22) being connectable to a respective electrical circuit carrying an AC or DC voltage; and a pressure controller (36) configured to control an internal pressure of the vacuum tight enclosure, wherein the pressure controller (36) is configured to selectively switch the internal pressure of the vacuum tight enclosure between: a first vacuum level that permits formation and maintenance of a glow discharge in the vacuum tight enclosure to allow a current to flow between the first and second electrodes (20, 22) via the glow discharge so as to turn on the vacuum switch; and a second vacuum level that inhibits formation and maintenance of a glow discharge in the vacuum tight enclosure to prevent a current from flowing between the first and second electrodes (20, 22) via the glow discharge so as to turn off the vacuum switch.

There is provided a vacuum switching assembly for switching an AC or DC current. The vacuum switching assembly comprises a vacuum switch. The vacuum switch includes: first and second electrodes (20, 22) located in a vacuum tight enclosure, the vacuum tight enclosure containing a gas or gas mixture, the first and second electrodes (20, 22) defining opposed electrodes being separated by a gap, each of the first and second electrodes (20,22) being connectable to a respective electrical circuit carrying an AC or DC voltage; and a pressure controller (36) configured to control an internal pressure of the vacuum tight enclosure, wherein the pressure controller (36) is configured to selectively switch the internal pressure of the vacuum tight enclosure between: a first vacuum level that permits formation and maintenance of a glow discharge in the vacuum tight enclosure to allow a current to flow between the first and second electrodes (20, 22) via the glow discharge so as to turn on the vacuum switch; and a second vacuum level that inhibits formation and maintenance of a glow discharge in the vacuum tight enclosure to prevent a current from flowing between the first and second electrodes (20, 22) via the glow discharge so as to turn off the vacuum switch.