Switching tubes

thumb|upright|Giant General Electric|GE hydrogen thyratron, used in pulsed [[radars, next to miniature 2D21 thyratron used to trigger relays in jukeboxes. Reference 2D21 tube is tall.]] A thyratron is a type of gas-filled tube used as a high-power electrical switch and controlled rectifier. Thyratrons can handle much greater currents than similar hard-vacuum tubes. Electron multiplication occurs when the gas becomes ionized, producing a phenomenon known as a Townsend discharge. Gases used include mercury vapor, xenon, neon, and (in special high-voltage applications or applications requiring ve

gap between two electrodes that is used for generating sparks

right|thumb|250px|(1) Anode, (2) Cathode, (3) Ignitor, (4) Mercury, (5) Ceramic insulators, (6) Cooling fluid An ignitron is a type of gas-filled tube used as a controlled rectifier and dating from the 1930s. Invented by Joseph Slepian while employed by Westinghouse, Westinghouse was the original manufacturer and owned trademark rights to the name "Ignitron". Ignitrons are closely related to mercury-arc valves but differ in the way the arc is ignited. They function similarly to thyratrons; a triggering pulse to the igniter electrode turns the device "on", allowing a high current to flow betwee

In electronics, a Dekatron (or Decatron, or generically three-phase gas counting tube or glow-transfer counting tube or cold cathode tube) is a gas-filled decade counting tube. Dekatrons were used in computers, calculators, and other counting-related products during the 1950s and 1960s. "Dekatron" was the brand name used by Ericsson Telephones Limited (ETL), of Beeston, Nottingham (not to be confused with the Swedish TelefonAB Ericsson of Stockholm) and has since become a generic trademark. The device was invented by John Reginald Acton, with the patent assigned to Ericsson.

thumb|upright|Trigatron CV100, with loose-knit "sock" to contain any explosion A trigatron is a type of triggerable spark gap switch designed for high current and high voltage (usually 10–100 kV and 20–100 kA, though devices in the mega-ampere range exist as well). It has very simple construction and in many cases is the lowest cost high energy switching option. It may operate in open air, it may be sealed, or it may be filled with a dielectric gas other than air or a liquid dielectric. The dielectric gas may be pressurized, or a liquid dielectric (e.g. mineral oil) may be substituted to furth

thumb|upright|KN2 "Krytron" switch tube, made by EG&G (about 25 mm tall) The krytron is a cold-cathode gas-filled tube intended for use as a very high-speed switch, somewhat similar to the thyratron. It consists of a sealed glass tube with four electrodes. A small triggering pulse on the grid electrode switches the tube on, allowing a large current to flow between the cathode and anode electrodes. The vacuum version is called a vacuum krytron, or sprytron. The krytron was one of the earliest developments of the EG&G Corporation.