How LEDs Work

LEDs (Light-Emitting Diodes) convert electrical energy DIRECTLY into LIGHT — efficiently and with little heat waste. Old INCANDESCENT bulbs heat a wire until it glows (most energy lost as heat — only ~5% becomes light). LEDs convert ~50% of energy to light. They last 10-25x longer. They allow countless colors. They are now the dominant lighting technology.

How they work. An LED is a semiconductor diode. When current flows through it in the right direction, electrons in the semiconductor recombine with electron HOLES, releasing energy as PHOTONS (light). The COLOR depends on the band gap of the material: red, green, blue, IR, UV all use different semiconductor compounds. WHITE LEDs are typically blue LEDs with a phosphor coating that converts some blue to other colors, mixing to white. The 2014 NOBEL PRIZE in Physics went to inventors of efficient blue LEDs — completing the white-light puzzle.

Where LEDs are. EVERYWHERE: home and street lighting, car headlights, smartphone screens, TV displays, traffic lights, status indicators, grow lights for indoor farming, medical devices, decorative items. SAVING ENERGY: global LED adoption is one of climate's quiet wins — saves billions of kWh annually. CHALLENGES: blue light affecting sleep cycles; light pollution; recycling. The technology continues to improve in efficiency, color quality, and cost.

LEDs replaced one of humanity's oldest technologies — the burning filament. The energy savings are vast, the colors more flexible, the lifespan dramatically longer. A quiet revolution.