An infrared emitter, or IR emitter, is a source of light energy in the infrared spectrum. It is a light emitting diode (LED) that is used in order to transmit infrared signals from a remote control. In general, the more they are in quantity and the better the emitters are, the stronger and wider the resulting signal is. A remote with strong emitters can often be used without directly pointing at the desired device. Infrared emitters are also partly responsible for limits on the range of frequencies that can be controlled. An IR emitter generates infrared light that transmits information and commands from one device to another. Typically one device receives the signal then passes the infrared (IR) signal through the emitter to another device.
The most common sizes for wavelength are 875nm, 850nm, 940nm.
A. Infrared LED with wavelength of 940nm: suitable to be used in remote controller, such as remote controllers for household appliances.
B. 850nm: suitable to be used in video cameras that are applied in digital photography, monitoring system, door phone, theft-proof alarm and so on.
C. 870nm: suitable to be used in IrDA compatible data transmission, IR illumination for CCTV, miniature light barriers, Photo interrupter, optical switches, shaft encoders and more.