Post on 09-May-2015
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- 1. By; Jayamalie, Prashadhi, Dicra, Shanya, Vikum ya, Shenal , Ashik, Hashan & Roshen
2. THEORETIC HISTORY- ARGUEBasic Principle How Incandescent LampsWork. In 1802, Humphry Davy demonstrated that by runningelectricity through a thin strip of metal, that strip couldbe heated to temperatures high enough so they wouldgive off light. The strip of metal, called a filament, isresistance to the electricity flowing through it (thethinner the metal, the higher resistance). Theresistance turns the electrical energy into heat, andwhen the filament becomes white-hot, it gives off light.It incandesces because of the heat. 3. PRACTICAL HISTORY- COMBAT In the decades of Davys demonstration, other scientistsand inventors tried to develop workable incandescentlamps. But these lamps were delicate, unreliable, shortlived, and expensive to operate. The lifetime was shortbecause the filaments used would burn up in air. Tocombat the short lifetime, early developers used thick, lowresistance filaments, but heating them to incandescencerequired large electrical currents and generating currentwas costly. These problems arose in improving the technologies ofthe incandescent lamp. 4. 1802- Humphry Davy, had the mostpowerful battery and he created the firstincandescent light bulb by passingcurrent through a platinum strip. By 1964, improvements in production ofincandescent lamps increased sinceEdisons lighting system. 5. The Incandescent light bulb produces light byheating a metal filament wire to a hightemperature until it glows. the hot filament is protected from oxidation inthe air with a glass enclose that is filled withinert gas or evacuated. In a halogen lamp, filament evaporation isprevented by a chemical process that redepositmetal vapor into the filament, extending its life. the light bulb is supplied with electrical currentby feed-through terminals or wires embedded inthe glass. Most bulbs are used in a socket which providesmechanical support and electrical connection. 6. IncandescentBulb 7. Availability of incandescent lights Incandescent bulbs are available in a wide range ofsizes, light output, and voltage ratings, from 1.5volts to about 300 volts. They require no externalregulating equipment, have low manufacturingcosts, and work equally well on either alternatingcurrent or direct current. As a result, theincandescent lamp is used often in household andcommercial lighting, especially for portable lightingsuch as table lamps, car headlamps, flashlights , andfor decorative and advertising lighting. 8. Incandescent lights are availablein various forms, sizes andshapes. Few categories includingthese can be listed as follows 9. For Decorative purposes : Globe shaped incandescent lights : Tubular incandescent lights : 10. Coloured incandescent lights Low voltage incandescent lights 11. Antique replica incandescent lights : Incandescent black lights : 12. What color is electric light?A glowing filament is white, and we describeits incandescent light as white. However, theactual wavelength components of differentelectric light sources vary, so that weperceive white with a bluish cast as "cool"and white with a pinkish cast as "warm". Asthese labels are vague, tools such as thecolor rendering index (CRI) and colortemperature have been developed. 13. Color temperatureColor temperature is adescription of the warmthor coolness of a lightsource. When a piece ofmetal is heated, the colorof light it emits will change.This color begins as red inappearance andgraduates to orange,yellow, white, and thenblue-white to deepercolors of blue. 14. THE USABILITY OF INCANDESCENTBULBSThe uses of Incandescent bulbs can be categorized into two different ways.1. The uses of incandescent bulbs as a modeof light2. The uses of heat generated by the filamentof the Incandescent bulbs 15. THE INCANDESCENT BULBS ARE WIDELY USED IN Household lighting Commercial lighting Table lamps Car headlamps Flashlights Decorative and advertising lighting 16. Incandescentbulbs are less efficient than several other modern types of light bulbs. Most incandescent bulbs convert less than 5% of the energy they use into visible light with the remaining energy being converted into heat. 17. Screw TypeThe screw type is very common with incandescentbulbs. Screw cap is simply a screw that is twisted intothe socket, and is known more precisely as the Edison screw cap after its inventor, Thomas Edison.They come in a variety of different diameters, from asmall screw cap to a giant screw, a factor that ensures only the right bulb can ever be fitted. This style is notexclusive to any particular appliance, though recessed down lights all make good use of it. Halogen and CFLlights are all widely available with screw caps, making it easy for home owners to switch from the incandescent to the greener option. 18. Pin TypeThe bi pin cap has a number of different designs, but it can be fixed by pushing the bulb into the socket and held tightly there. The pins themselves can be different in appearance. For example, the miniature halogen clear capsule has a g9 bi pincap, which has pins that appear more like hooped wires. The gu10 bipin, meanwhile, has pins that seem more like short metal stumps through the baseof the cap.The range of bi pin caps is surprisingly wide, but not only because of the style ofthe pins. Generally the model number is an indication of the measurement between the pins, with g9 halogen bulbs boasting a space of 9mm between the two pins. This type of bulb is used for small decorative light fittings around the house. Spotlights and recessed lights, however, most often use gu10 LED bulbs, which have pins spaced 10mm apart that work on a twist and lock basis. One of theadvantages of this model is that it is widely recognised as one of the safest types ofmains voltage caps since the live parts are concealed in the socket. When it comes to fluorescent tubes, the pins are different in structure again, simply protruding fromboth ends. However, CFL bulbs can increase to 4 pins, depending on the particularbulb design. 19. Cost of lighting The initial cost of an incandescent bulb is small compared to thecost of the energy it uses over its lifetime. A comparison ofincandescent lamp operating cost with other light sources mustconsider the luminous efficacy of each lamp. The comparisonmust include illumination requirements, capital cost of thelamp, labor cost to replace lamps, various depreciation factors forlight output as the lamp ages, effect of lamp operation onheating and air conditioning systems, and energy consumptionas well.[ 40w=75/- 60w=75/- 75w=70/- 100=70/- 20. Areas to be use Incandescent bulbs can to be use any kind ofareas.As ex:- rooms, passageareas, houses, exteriorlighting(buildings, gardens)interior lightings (houses and buildings) also.It depend on what is the clientwants, colors, cost of lights.