High-intensity discharge (HID) lamps produce light through an electric arc between tungsten electrodes housed inside an arc tube. They create more visible light per unit of power than fluorescent and incandescent lamps. Different types of HID lamps use various chemistries in the arc tube to achieve desired light characteristics, including mercury vapor, metal halide, sodium vapor, and xenon short-arc lamps. HID lamps are commonly used when large areas need high levels of bright, energy efficient lighting, such as in warehouses, stadiums, and outdoor spaces. They provide benefits like higher visibility, longer lifespan, and greater energy efficiency compared to traditional lighting, but also have higher upfront costs.