The light bulb as a symbol for a new idea comes from cartoons, where a glowing bulb appeared above a character's head at the moment of inspiration. Online editors turned that visual gag into an audio cue, pairing a switch click and ding with reaction shots and text overlays. The clip spread through meme edits, explainer videos and short tech content, where a three second sound is long enough to signal a breakthrough but short enough to reuse repeatedly without slowing the pace of a scene.