ABSTRACT
This chapter examines fundamental concepts of illumination. Understanding of illumination and efficacies of various lighting systems is an important and integral part of electrical engineering. Lighting system design is driven primarily by the illuminance requirement at the point of interest. An illuminance level is selected for a specific activity or task based on an aggregate weighting factor derived from a combination of age of occupants, specific activity, pace or frequency, venue, level of importance, and background or surface reflectance. Lamberts law, also called the cosine law, establishes the relationship between the illuminance on a surface, or target, the illuminance at the source, and the angle “θ” the inclined source radiation portends with respect to the target surface’s normal vector. The illuminance cosine-cubed law can be viewed as a combination of the Lambert’s law and the inverse square law. There are various methods for determining, accessing or computing the coefficient of utilization values for specific lighting system scenarios.
