The document discusses the history and operation of incandescent light bulbs. It explains that in 1802, Humphry Davy demonstrated that running electricity through a thin metal strip could heat it enough to produce light. However, early light bulbs had short lifetimes due to filament burn up in air. Improvements were made to combat this, but generating electricity was costly. The document also describes how incandescent bulbs work, their availability in different sizes and voltages, their uses, and properties like color temperature.

1.  By;
Jayamalie, Prashadhi, Dicra, Shanya, Vikum
ya, Shenal , Ashik, Hashan & Roshen

3. 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.

4. PRACTICAL HISTORY- “COMBAT”
 In the decades of Davy's 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.

5.  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.

6.  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.

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8. 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.

9. Incandescent lights are available
in various forms, sizes and
shapes. Few categories including
these can be listed as follows

10.  For Decorative purposes :
 Globe shaped incandescent lights :
 Tubular incandescent lights :

11.  Coloured incandescent lights
 Low voltage incandescent lights

12.  Antique replica incandescent lights :
 Incandescent black lights :

13. What color is electric light?
A glowing filament is white, and we describe
its incandescent light as white. However, the
actual wavelength components of different
electric light sources vary, so that we
perceive white with a bluish cast as "cool"
and white with a pinkish cast as "warm". As
these labels are vague, tools such as the
color rendering index (CRI) and color
temperature have been developed.

14. Color temperature
Color temperature is a
description of the warmth
or coolness of a light
source. When a piece of
metal is heated, the color
of light it emits will change.
This color begins as red in
appearance and
graduates to orange,
yellow, white, and then
blue-white to deeper
colors of blue.

16. THE USABILITY OF INCANDESCENT
BULBS
The uses of Incandescent bulbs can be
categorized into two different ways.
1. The uses of incandescent bulbs as a mode
of light
2. The uses of heat generated by the filament
of the Incandescent bulbs

17. THE INCANDESCENT BULBS ARE WIDELY USED IN
 Household lighting
 Commercial lighting
 Table lamps
 Car headlamps
 Flashlights
 Decorative and advertising lighting

18.  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.

19. Screw Type
The screw type is very common with incandescent
bulbs. Screw cap is simply a screw that is twisted into
the 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 a
small screw cap to a giant screw, a factor that ensures
only the right bulb can ever be fitted. This style is not
exclusive to any particular appliance, though recessed
down lights all make good use of it. Halogen and CFL
lights are all widely available with screw caps, making
it easy for home owners to switch from the
incandescent to the greener option.

20. Pin Type
The 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 bi
pin, 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 of
the 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 the
advantages of this model is that it is widely recognised as one of the safest types of
mains 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 from
both ends. However, CFL bulbs can increase to 4 pins, depending on the particular
bulb design.

21.  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/-

22. 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.