My teacher asked me to do so.Took help from few other slides

1. Illumination
Presented By:
Avijit Nanda
B416057

2. Types of Electrical
Lightings
1. Incandescent Lamps
2. Fluorescent Lamps
3. Mercury Lamps
4. Sodium Vapour Lamps
5. Halogen Lamps
6. Carbon Filament Lamps
7. Compact Fluorescent Lamps

3. Incandescent lamp
Incandescent lamp or incandescent light
globe is an electric light which produces light
with a filament wire heated to a high
temperature by an electric current passing
through it, until it glows .The hot filament is
protected from oxidation with a glass or quartz
bulb that is filled with inert gas or evacuated.
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 connections .

4. Fluorescent lamp
A fluorescent lamp or fluorescent tube is a low
pressure mercury-vapour gas-discharge
lamp that uses fluorescence to produce visible
light. An electric current in the
gas excites mercury vapour which produces
short-wave ultraviolet light that then causes
a phosphor coating on the inside of the bulb to
fluoresce, producing visible light. A fluorescent
lamp converts electrical power into useful light
much more efficiently than incandescent lamps.
The luminous efficacy of a fluorescent light bulb
can exceed 100 lumens per watt, several times
the efficacy of an incandescent bulb with
comparable light output.

5. Mercury lamps
A mercury vapour lamp is a gas discharge
lamp that uses an electric arc through
vaporized mercury to produce light. The arc
discharge is generally confined to a
small fused quartz arc tube mounted within a
larger borosilicate glass bulb. The outer bulb
may be clear or coated with a phosphor; in
either case, the outer bulb provides thermal
insulation, protection from
the ultraviolet radiation the light produces,
and a convenient mounting for the fused
quartz arc tube.

6. Sodium-vapour lamp
A sodium-vapour lamp is a gas-discharge
lamp that uses sodium in an excited state to
produce light. There are two varieties of such
lamps: low pressure and high pressure. Low-
pressure sodium lamps are the most efficient
electrical light sources, but their yellow light
restricts applications to outdoor lighting such as
street lamps. High-pressure sodium lamps have a
broader spectrum of light than the low pressure,
but still poorer colour rendering than other types of
lamps. Low pressure sodium lamps only
give monochromatic yellow light and so inhibit
colour vision at night.

7. A halogen lamp, also known as a tungsten
halogen, quartz-halogen or quartz iodine lamp, is an
incandescent lamp that has a small amount of
a halogen such as iodine or bromine added. The
combination of the halogen gas and
the tungsten filament produces a halogen
cycle chemical reaction which redeposit evaporated
tungsten back onto the filament, increasing its life and
maintaining the clarity of the envelope. Because of
this, a halogen lamp can be operated at a higher
temperature than a standard gas-filled lamp of similar
power and operating life, producing light of a
higher luminous efficacy and colour temperature.

8. A compact fluorescent lamp (CFL), also
called compact fluorescent light, energy-saving light,
and compact fluorescent tube, is a fluorescent
lamp designed to replace an incandescent lamp;
some types fit into light fixtures formerly used for
incandescent lamps. The lamps use a tube which is
curved or folded to fit into the space of an
incandescent bulb, and a compact electronic
ballast in the base of the lamp.
Compared to general-service incandescent lamps
giving the same amount of visible light, CFLs use
one-fifth to one-third the electric power, and last eight
to fifteen times longer. A CFL has a higher purchase
price than an incandescent lamp, but can save over
five times its purchase price in electricity costs over
the lamp's lifetime
Compact fluorescent
lamp(CFL)