The presentation introduces light-emitting diodes (LEDs) and discusses their advantages and disadvantages. LEDs convert electrical energy to light and have benefits including high efficiency, dimming ability, slim design, long lifespan, and lower power consumption compared to other lighting technologies. However, LEDs can be more expensive initially and their color may shift with age and temperature. The presentation provides examples of LED applications in sensors, signs, signals, and mobile devices and concludes they are a very low energy light source that can last over 50,000 hours.