An infrared transmitting tube, also known as an infrared light-emitting diode (IR LED), is a type of diode that converts electrical energy directly into near-infrared light, which is invisible to the human eye. It emits this radiation through a light-emitting device and is primarily used in photoelectric switches and remote control systems.

The structure and working principle of an IR LED are similar to those of a standard LED, but it uses different semiconductor materials. Common materials include gallium arsenide (GaAs) and aluminum gallium arsenide (GaAlAs). These LEDs are typically encapsulated in transparent, light blue, or black resin for optimal performance and durability.