LEDs (Light-Emitting Diodes) are semiconductor devices that emit light through electroluminescence rather than through traditional light sources. This basic fact is the foundation for many of the advantages of LEDs compared to traditional lamps, including directional light emission, wide size and form factor choice, resistance to mechanical failure (i.e., breaking), instant “on” at full output, rapid on-off cycling capability without detrimental effects, improved performance at cold temperatures, dimming and control capability, opportunity for color tuning, minimal nonvisible radiation [e.g., ultraviolet (UV), infrared (IR)], and extended lifetime.
But even though LEDs have advantages over traditional lamps, generalized comparisons are often misrepresentative. For example, no matter how much energy can be saved using an LED, if the LED does not meet all the performance requirements of a given application, it is not a good design choice. This 3 Hour course describes the characteristics of LEDs and discusses situations where LEDs would be appropriate and other situations where traditional light sources should be chosen instead. Health and safety issues of LEDs are also discussed.