What is the main characteristic of a Light Emitting Diode (LED)?

The main characteristic of a Light Emitting Diode (LED) is that it emits light when electric current flows through it. This phenomenon occurs due to electroluminescence, where light is produced as a result of electrons recombining with holes in the semiconductor material of the LED. When current passes through the LED, it energizes the electrons, causing them to release energy in the form of photons, which is the light that we see.

This unique property makes LEDs highly efficient lighting sources, as they convert a greater percentage of electricity into visible light compared to traditional incandescent bulbs. LEDs are commonly used in various applications ranging from indicators and displays to general lighting due to their compact size, longevity, and energy efficiency.