The invention of the light bulb is usually attributed to Thomas Edison (11 February 1847-18 October 1931), but Edison’s team simply perfected its characteristics. The electric lamp is an artificial light source powered by electricity. The bulbs are distinguished, based on their operating system , in incandescent lamps, arc lamps and LED lamps.
Incandescent lamps
The incandescent lamp is a lamp that invented by the American Thomas Edison and now withdrawn from the market. It includes a thin metal thread from heavy, refractory metal, usually tungsten, wrapped in spirals. This is carried by the edges of the welded two thicker wires wherein the electrical voltage which sets the electric charges in motion and which causes the yarn to illuminate by heating it at 2600 ° C is applied. When the length of the yarn is larger than 2 cm, then this is retained and intermediate non-electrified wires in a radial arrangement. This construction is enclosed in a spherical glass or elliptical low gas pressure cartridge. The cartridge is in low power lamps empty, or contains inert gas, usually nitrogen or high power lamps and halogen (iodine) for halogen bulbs. The lamp may be a screwed contact connected to a pole and a contact base which is connected to the other pole. The power consumed is 25-1000W. The color of light is white. The lifetime of this lamp type is 750-1500 hours of continuous operation. The greater the power, the shorter the life. The incandescent lamp is lit only when both contacts touch in both battery terminals or plug. When the lamp is not lit, (burned by excessive growth of electricity short) the filament is cut. Used for residential lighting, shop, automobile etc. The incandescent lamp generates less eye problems because it provides a constant and not variable light which also approximates satisfactory to the human eye the natural sunlight, in terms of uniformity of distribution of frequencies emerge. The incandescent lamp tends towards abolition for energy purposes in use, which directly involve environmental reasons. Already the halogen lamp is used for projectors. A key disadvantage of this lamp its sensitivity to changes in voltage.
ARC LAMPS
The arc lamp is a specialist lamp mainly contains metal vapor and perhaps helped by a noble gas. Electrodes at the ends of the work is essentially filament yarn. The heating is performed initially in a special circuit that automatically interrupted as soon the irradiation of the lamp starts, when the heating is maintained by the current of the arc, or they are heated by the arc itself that starts form a glow, which is formed because the gas containing the tube. The heating of these lamps, although it is lower than that of incandescent lamps, it is necessary both for the evaporation of the metal containing and usually mercury or sodium, and to a limited area of the electrodes to emit electrons easily. The arc lamps are particularly dangerous to the environment, mercury is highly toxic and should be avoided to make use of infected more items like carpets that has broken over them, and must not vacuumed, because they diffuse toxic materials in the air in a room. Also the arc lamps do flicker, which is highly visible when lamps are straight (not e.g. spiral shape), which is inconvenient and tiring the eyes.
