An ignitron is a type of controlled rectifier dating from the 1930s. Developed from the Cooper-Hewitt mercury arc rectifier, General Electric was the original manufacturer and owned trademark rights to the name "Ignitron". A rectifier is an electrical device, comprising one or more diodes arranged for converting alternating current (AC) to direct current (DC). ... // Events and trends The 1930s were spent struggling for a solution to the global depression. ... Peter Cooper Hewitt (May 5, 1861 - August 25, 1921) was an American electrical engineer, who demonstrated the mercury-vapor lamp for which he deposited a patent. ... A mercury arc valve is a type of electrical rectifier which converts alternating current into direct current. ... The General Electric Company, or GE, (NYSE: GE) is a multinational technology and services company. ...

It is usually a large steel container with a pool of mercury in the bottom, acting as a cathode. A large graphite block, held above the pool by an insulated electrical connection, serves as the anode. An igniting electrode is pulsed to force conduction through the mercury vapor between the cathode and anode. General Name, Symbol, Number Mercury, Hg, 80 Chemical series transition metals Group, Period, Block 12 (IIB), 6, d Density, Hardness liquid 13,579 kg/m3 solid @ −39 °C 15,600 kg/m3 1. ... Diagram of a copper cathode The electrode of an electrochemical cell at which reduction occurs is referred to as the cathode (from the Greek word κάθοδος = going down). In an electrolytic cell the cathode is negatively charged and in a galvanic cell the cathode is positively charged. ... Graphite (named by Abraham Gottlob Werner in 1789, from the Greek γραφειν: to draw/write, for its use in pencils) is one of the allotropes of carbon. ... An anode (from the Greek άνοδος = going up) is the positive electrode in an electrolytic system or circuit. ... An electrode is a conductor used to make contact with a nonmetallic part of a circuit (e. ...

Ignitrons were long used as high-current rectifiers in major industrial installations where thousands of amps of AC current must be converted to DC, such as aluminum smelters. Large electric motors were also controlled by ignitrons used in gated fashion, in a manner similar to modern semiconductor devices such as silicon controlled rectifiers and triacs. Many electric locomotives used them in conjunction with transformers to convert high voltage AC from the catenary to relatively low voltage DC for the motors. Because they are far more resistant to damage due to overcurrent or back-voltage, ignitrons are still manufactured and used in preference to semiconductors in certain installations. An alternating current (AC) is an electrical current where the magnitude and direction of the current varies cyclically, as opposed to direct current, where the direction of the current stays constant. ... Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ... General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13 (IIIA), 3, p Density, Hardness 2700 kg/m3, 2. ... A motor is a device that converts energy into mechanical power, and is often synonymous with engine. ... A silicon controlled rectifier is a 4 layer solid state device that controls current flow. ... A triac is an electronic component equivalent to two silicon controlled rectifiers (thyristors) joined in inverse-parallel (paralleled but with the polarity reversed) and with their gates connected together. ... A locomotive is a railway vehicle that provides the motive power for a train, and has no payload capacity of its own; its sole purpose is to move the train along the tracks. ... Transformers - Typical electrical configurations. ... Catenary In mathematics, the catenary is the shape of a hanging flexible chain or cable when supported at its ends and acted upon by a uniform gravitational force (its own weight). ...

See also

• Thyratron
• Thyristor
• Krytron
• Triggered spark gap