Lighting Operations
The lighting system
Live lighting combines fixtures, control, and power. Know fixture types - profile/spot, wash, beam, PAR, LED, moving heads - and their roles. Understand the console, DMX addressing, universes, and how channels map to attributes (intensity, colour, position, gobo). Colour is controlled via gels, dichroic filters, or LED mixing (RGB/RGBW).
Power and safety
Lighting draws significant current. Understand volts × amps = watts, phase balance, and why you must not overload circuits. Cables must be rated, routed safely, and protected from damage. Hot fixtures need clearance and cool-down time. Working at height with fixtures requires fall protection and correct use of ladders or lifts.
Focus and operation
A lighting plot maps fixture positions and channels. Focus sessions align beams to the stage. Cue stacks store looks; operators execute cues on the stage manager's call. Follow-spot operators need clear sightlines and communication.
Traps
Questions often test DMX limits (512 channels per universe) and the difference between a channel and a fixture attribute. Another trap is power: doubling fixtures on a circuit because "it worked last time." Beware options that ignore heat clearance or cable protection.
Worked example
A 2,000 W fixture on a 240 V supply draws about 8.3 A (2000 ÷ 240). Two such fixtures need about 16.7 A - fine on a 20 A circuit but not on a 10 A one. Always calculate before patching.
Rule of thumb
Calculate current before adding load, and treat every circuit as if it will be fully loaded.