Incandescent lamps are the conventional light sources, introduced in 1879. Incandescent bulbs also called as GLS (General Lighting Services), require no external regulating equipment like the ballast and work well on either alternating current or direct current. They offer lower procurement cost, good color qualities and optical control. They are also compatible with control devices such as dimmers and timers and can be used both indoors and outdoors. As a result, the incandescent lamp is widely used both in household and commercial lighting.