LED

LED (Light Emitting Diode) is an optoelectronic device that converts electrical energy directly into light. LEDs come in several colors. Often RGB (Red, Green, and Blue) LEDs are used together to enable a wide range of colors by varying the relative intensities of each LED. Infrared LEDs are often paired with light sensors to detect some change in the optical conditions between the LED and sensor.

References:

https://electronicscoach.com/led.html