LED (Light Emitting Diode) lighting uses semiconductor materials that emit photons when an electric current passes through. Unlike traditional light sources, LEDs are directional, instant-on, dimmable, and contain no mercury. Key metrics: luminous efficacy (80–200 lm/W), lifespan (50,000–100,000 hours), CRI (70–98), and CCT (2700K–6500K). LED technology dominates modern lighting across commercial, industrial, and residential applications due to its energy efficiency and long service life.