THEORETIC HISTORY- “ARGUE” Basic Principle How Incandescent Lamps Work. In 1802, Humphry Davy demonstrated that by running electricity through a thin strip of metal, that strip could be heated to temperatures high enough so they would give off light. The strip of metal, called a filament, is resistance to the electricity flowing through it (the thinner the metal, the higher resistance). The resistance turns the electrical energy into heat, and when the filament becomes white-hot, it gives off light. It incandesces because of the heat.
PRACTICAL HISTORY- “COMBAT” In the decades of Davys demonstration, other scientists and inventors tried to develop workable incandescent lamps. But these lamps were delicate, unreliable, short lived, and expensive to operate. The lifetime was short because the filaments used would burn up in air. To combat the short lifetime, early developers used thick, low resistance filaments, but heating them to incandescence required large electrical currents and generating current was costly. These problems arose in improving the technologies of the incandescent lamp.
1802- Humphry Davy, had the most powerful battery and he created the first incandescent light bulb by passing current through a platinum strip. By 1964, improvements in production of incandescent lamps increased since Edison’s lighting system.
The Incandescent light bulb produces light by heating a metal filament wire to a high temperature until it glows. the hot filament is protected from oxidation in the air with a glass enclose that is filled with inert gas or evacuated. In a halogen lamp, filament evaporation is prevented by a chemical process that redeposit metal vapor into the filament, extending its life. the light bulb is supplied with electrical current by feed-through terminals or wires embedded in the glass. Most bulbs are used in a socket which provides mechanical support and electrical connection.
Availability of incandescent lights Incandescent bulbs are available in a wide range of sizes, light output, and voltage ratings, from 1.5 volts to about 300 volts. They require no external regulating equipment, have low manufacturing costs, and work equally well on either alternating current or direct current. As a result, the incandescent lamp is used often in household and commercial lighting, especially for portable lighting such as table lamps, car headlamps, flashlights , and for decorative and advertising lighting.
Incandescent lights are availablein various forms, sizes andshapes. Few categories includingthese can be listed as follows
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.
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.
THE USABILITY OF INCANDESCENTBULBSThe uses of Incandescent bulbs can be categorized into two different ways.1. The uses of incandescent bulbs as a mode of light2. The uses of heat generated by the filament of the Incandescent bulbs
THE INCANDESCENT BULBS ARE WIDELY USED IN Household lighting Commercial lighting Table lamps Car headlamps Flashlights Decorative and advertising lighting
Incandescent bulbs 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.
Screw Type The 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.
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 pin cap, which has pins that appear more like hooped wires. The gu10 bipin, meanwhile, has pins that seem more like short metal stumps through the base of 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 particular bulb design.
Cost of lighting The initial cost of an incandescent bulb is small compared to the cost of the energy it uses over its lifetime. A comparison of incandescent lamp operating cost with other light sources must consider the luminous efficacy of each lamp. The comparison must include illumination requirements, capital cost of the lamp, labor cost to replace lamps, various depreciation factors for light output as the lamp ages, effect of lamp operation on heating and air conditioning systems, and energy consumption as well.[ 40w=75/- 60w=75/- 75w=70/- 100=70/-
Areas to be use Incandescent bulbs can to be use any kind of areas. As ex:- rooms, passage areas, houses, exterior lighting(buildings, gardens) interior lightings (houses and buildings) also. It depend on what is the client wants, colors, cost of lights.