Light by definition connotes Electromagnetic
radiation that has a wavelength in the range from about 4,000 (violet) to about
7,700 (red) angstroms and may be perceived by the normal unaided human eye. In
fact in the prehistoric days, all human activities were coordinated with
Sunrise and Sunset. Today, in principle activities are carried out round the
clock. All this is made possible because of Artificial Lighting systems. The
lighting systems comprise of a source employing any physical phenomenon among.
Incandescence, Electrolumniescence or
Flourescence. Some control scheme and a Luminaire. In fact all this has lead to
a class of professionals called Lighting Engineers or Illumination Engineers.
Unlike other group of professionals they need to be adept at not only at exact
sciences of Maths, Physics, Chemistry; but be wary of Physiology and Psychology
of users (like a medical professional); have good aesthetic sense and
economically utilize resources.Efficacy of these systems is talked in terms of
Illuminance per Watt of energy consumed. Efforts are on to reduce energy
conmsumption yet have efficient Illumination to enhance productivity. Need less
to mention that all these sources employ electrical energy.Trend these days is
to employ, modern electronic controls together with energy efficient
lamps.These aspects are borne in mind, right from the planning stage of a
building. As electrical energy is being used for the purpose, it becomes
important for Illuminating Engineer to come up with an integrated system for
the complete electrical system of a building.