Iilumination by absar ahsan

ILLUMINATION

ENROLLMENT NO. :-140170116001

NAME: - Absar Ahsan

ILLUMINATION

When light falls on any surface, the phenomena is known as illumination.

LAMP

TYPE OF LAMPS

Incandescent

Discharge lamp

INCANDESCENT LAMP

Hot wire – filament sealed in a glass jar (bulb).

Electric current pass through the wire heats it to incandescence, and the wire emits light.

PARTS OF INCANDESCENT BULB

ADVANTAGES :

1. Less expensive

2. Easier to dim with rheostats

3. Warmer color than fluorescent and tungsten-halogen lamps

4. Light output is relatively high

DISADVANTAGES:

1. Energy inefficient

2. Short lamp life time

3. Warm source

Discharge lamps

Light is produced by passage of an electric current through a vapor or gas, rather than through a tungsten wire as in incandescent lamp.

DISCHARGE LAMP

Fluorescent

Sodium lamp

Mercury lamp

REFLECTOR&

FIXTURE

Reflector

Reflector is a device that causes reflection

OR

Bounces back the light.

Fixture

Light fixture provides support and electrical connection to lamp.

It control , distribute and direct light on object.

Lighting Schemes

Lighting schemes are classified according to the location, requirement and purpose are as under :

1. Direct lighting2. Indirect lighting3. Semi direct lighting 4. Semi indirect lighting5. General lighting

Direct Lighting

As is clear from the name, in this system almost 90 to 95 % light falls directly on the object or the surface.

Indirect LightingIn this system, the light does not fall directly on the surface but more than 90% of light is directed upwards by using diffusing reflectors.

Here the ceiling acts as a source of light and this light is uniformly distributed over the surface and glare is reduced to minimum.

Semi direct Lighting

Here transparent type shades are used through which about 60 % light is directed downward and 40 % is directed upward. This is an efficient system of lighting and chances of glare are also reduced.

Semi indirect Lighting

In this system about 60% to 90 % of total light is thrown upward to the ceiling for diffused reflection and the rest reaches the working plane directly. A very small amount of light is absorbed by the bowl.

General Lighting

This system employs such type of luminaries, shades and reflectors which give equal illumination in all the directions.