Technical Theatre/Lighting/The Designer
The lighting designer, or LD, is responsible for the creative aspect of the electrics team. They decide how much light, with what colors, and textures, from what angles, and so forth are needed. The LD must coordinate with the director, and other designers, to create the look, feel, mood, etc. of the show, and then make those ideas a reality through lighting.
Depending on the size of the company what is expected of a designer can vary greatly. In larger shows the LD will have an assistant, who often does most of the technical drafting, a Master Electrician, who is responsible for making that drafting a physical reality, and a lighting console programmer, who controls the actual lights, through control software, to the designers will. Any or all of these jobs can fall to a lighting designer in smaller companies, taking him away from the creative element of the show and into the technical details.