Arc lamp – wikipedia 7 gas station

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An arc lamp or arc light is a lamp that produces light by an electric arc (also called a voltaic arc). The carbon arc light, which consists of an arc between carbon electrodes in air, invented by Humphry Davy in the first decade of the 1800s, was the first practical electric light. [1] It was widely used starting in the 1870s for street and large building lighting until it was superseded by the incandescent light in the early 20th century. [1] It continued in use in more specialized applications where a high intensity youtube gas station karaoke point light source was needed, such as searchlights and movie projectors until after World War II. The carbon arc lamp is now obsolete for most of these purposes, but it is still used as a source of high intensity ultraviolet light.

The term is now used for gas discharge lamps, which produce light by an arc between metal electrodes through an inert gas in a glass bulb. The common fluorescent lamp is a low-pressure mercury arc lamp electricity for dummies pdf. [2] The xenon arc lamp, which produces a high intensity white light, is now used in many of the applications which formerly used the carbon arc, such as movie projectors and searchlights.

An arc is the discharge that occurs when a gas is ionized. A high voltage is pulsed across the lamp to ignite or strike the arc, after which the discharge can be maintained at a lower voltage. The strike requires an electrical circuit with an igniter and a ballast. The ballast is wired in series with the lamp and performs two functions.

First, when the power is first switched on, the igniter/starter (which is wired in parallel across the lamp) sets up a small current through the ballast and starter. This creates a small magnetic field within the ballast windings. A moment later the starter interrupts the current flow from the ballast, which has a high inductance and therefore tries to maintain the current flow (the ballast opposes any change in current e electricity bill through it); it cannot, as there is no longer a ‘circuit’. As a result, a high voltage appears across the ballast momentarily, to which the lamp is connected; therefore the lamp receives this high voltage across it which ‘strikes’ the arc within the tube/lamp. The circuit will repeat this action until the lamp is ionized enough to sustain the arc.

In popular use, the term arc lamp means carbon arc lamp only. In a carbon arc electricity worksheets for grade 1 lamp, the electrodes are carbon rods in free air. To ignite the lamp, the rods are touched together, thus allowing a relatively low voltage to strike the arc. [1] The rods are then slowly drawn apart, and electric current heats and maintains an arc across the gap. The tips of the carbon rods are heated and the carbon vaporizes. The carbon vapor in the arc is highly luminous, which is what produces the bright light. [1] The rods are slowly burnt away in use, and the distance between them needs to be regularly adjusted in order to maintain the arc. [1]

Many ingenious mechanisms were invented to effect the distance automatically, mostly based on solenoids. In one of the simplest mechanically-regulated forms gas yourself (which was soon superseded by more smoothly acting devices) the electrodes are mounted vertically. The current supplying the arc is passed in series through a solenoid attached to the top electrode. If the points of the electrodes are touching (as in start up) the resistance falls, the current increases and the increased pull from the solenoid draws the points apart. If the arc starts to fail the current drops and the points close up again.

The concept of carbon-arc lighting was first demonstrated by Sir Humphry Davy in the early 19th century (sources disagree about the year he first demonstrated it; 1802, 1805, 1807 and 1809 are all mentioned), using charcoal sticks and a two thousand cell battery to create an arc across a 4-inch (100 mm) gap. He mounted his electrodes horizontally and noted that, because of the strong convection flow of air, the arc formed the shape of an arch. He coined electricity formulas physics the term arch lamp, which was contracted to arc lamp when the devices came into common usage. [4]

In the late nineteenth century, electric arc lighting was in wide use for public lighting. The tendency of electric arcs to flicker and hiss was a major problem. In 1895, Hertha Ayrton wrote a series of articles for the save electricity pictures Electrician, explaining that these phenomena were the result of oxygen coming into contact with the carbon rods used to create the arc. [ citation needed] In 1899, she was the first woman ever to read her own paper before the Institution of Electrical Engineers (IEE).[1] Her paper was entitled The Hissing of the Electric Arc.

In the United States, there were attempts to produce arc lamps commercially after 1850, but the lack of a constant electricity supply thwarted efforts. Thus electrical engineers began focusing on the problem of improving Faraday’s dynamo. The concept was improved upon by a number of people including William Staite and Charles F. Brush. It was not until the 1870s that lamps such as the Yablochkov candle were more commonly seen. In 1877, the Franklin Institute conducted a comparative test of dynamo systems. The one developed by Brush performed best, and Brush immediately applied his improved dynamo to arc-lighting an early application being Public Square in Cleveland, Ohio, on April 29, 1879. [6] In 1880, Brush established the Brush Electric Company.

800 lights in rolling mills, steel works, shops, 1,240 lights in woolen, cotton electricity lessons for 5th grade, linen, silk, and other factories, 425 lights in large stores, hotels, churches, 250 lights in parks, docks, and summer resorts, 275 lights in railroad depots and shops, 130 lights in mines, smelting works, 380 lights in factories and establishments of various kinds, 1,500 lights in lighting stations, for city lighting, 1,200 lights in England and other foreign countries.

There were three major advances in the 1880s: František Křižík invented in 1880 a mechanism to allow the automatic adjustment of the electrodes. The arcs were enclosed in a small tube to slow the carbon consumption (increasing the life span to around 100 hours). Flame arc lamps were introduced where the carbon rods gas in oil pan had metal salts (usually magnesium, strontium, barium, or calcium fluorides) added to increase light output and produce different colours.

In the U.S., patent protection of arc-lighting systems and improved dynamos proved difficult and as a result the arc-lighting industry became highly competitive. Brush’s principal competition was from the team of Elihu Thomson and Edwin J. Houston. These two had formed the American Electric Corporation electricity jewels in 1880, but it was soon bought up by Charles A. Coffin, moved to Lynn, Massachusetts, and renamed the Thomson-Houston Electric Company. Thomson remained, though, the principal inventive genius behind the company patenting improvements to the lighting system. Under the leadership of Thomson-Houston’s patent attorney, Frederick P. Fish, the company protected its new patent rights. Coffin’s management also led the company towards an aggressive policy of buy-outs and mergers with competitors. Both strategies reduced competition in the electrical lighting manufacturing industry. By 1890, the Thomson-Houston company was the dominant electrical manufacturing company in the U.S. [8] Nikola Tesla received U.S. Patent 447920, Method of Operating Arc-Lamps (March 10, 1891), that describes a 10,000 cycles per second alternator to suppress the disagreeable sound of power-frequency harmonics produced v lab electricity by arc lamps operating on frequencies within the range of human hearing.

Around the turn of the century arc-lighting systems were in decline, but Thomson-Houston controlled key patents to urban lighting systems. This control slowed the expansion of incandescent lighting systems being developed by Thomas Edison’s Edison General Electric Company. Conversely, Edison’s control of direct current distribution and generating machinery patents blocked further expansion of Thomson-Houston. The roadblock to expansion was removed when the two companies merged in 1892 to form the General Electric Company. [8]

Arc lamps were used in some early motion-picture studios gas news uk to illuminate interior shots. One problem was that they produce such a high level of ultra-violet light that many actors needed to wear sunglasses when off camera to relieve sore eyes resulting from the ultra-violet light. The problem was solved by adding a sheet of ordinary window glass in front of the lamp, blocking the ultra-violet. [ citation needed] By the dawn of the talkies, arc lamps had been replaced in film studios with other types of lights. [ citation needed] In 1915, Elmer Ambrose Sperry began manufacturing his invention of a high-intensity carbon arc searchlight. These were used aboard warships of all navies during the 20th century for signaling and illuminating enemies. [9] In the 1920s, carbon arc lamps were sold as family health products, a substitute for natural sunlight. [10]

Arc lamps were superseded by filament lamps in most roles, remaining in only certain niche applications such as cinema projection, followspots, and searchlights. Even in these applications conventional gas near me open now carbon arc lamps are being pushed into obsolescence by xenon arc lamps, but were still being manufactured as spotlights at least as late as 1982 [11] and are still manufactured for at least one purpose – simulating sunlight in accelerated aging machines intended to estimate how fast a material is likely to be degraded by environmental exposure. [12] [13] See also [ edit ]