Electroluminescence (EL) is an optical phenomenon and electrical phenomenon in which a material emits light in response to the passage of an electric current or to a strong electric field. This is distinct from black body light emission resulting from heat (incandescence), from a chemical reaction (chemiluminescence), sound (sonoluminescence), or other mechanical action (mechanoluminescence).
Electroluminescence is the result of radiative recombination of electrons and holes in a material, usually a semiconductor. The excited electrons release their energy as photons - light. Prior to recombination, electrons and holes may be separated either by doping the material to form a p-n junction (in semiconductor electroluminescent devices such as light-emitting diodes) or through excitation by impact of high-energy electrons accelerated by a strong electric field (as with the phosphors in electroluminescent displays).
LED Wiki: Wi-Fi, Zigbee and Bluetooth compared
Key characteristics of ZigBee, Wi-Fi and Bluetooth
|Range||10-100 meters||50-100 meters||10 – 100 meters|
|Networking Topology||Ad-hoc, peer to peer, star, or mesh||Point to hub||Ad-hoc, very small networks|
|Operating Frequency||868 MHz (Europe) 900-928 MHz (NA), 2.4 GHz (worldwide)||2.4 and 5 GHz||2.4 GHz|
|Complexity (Device and application impact)||Low||High||High|
|Power Consumption (Battery option and life)||Very low (low power is a design goal)||High||Medium|
|Security||128 AES plus application layer security|| ||64 and 128 bit encryption|
|Typical Applications||Industrial control and monitoring, sensor networks, building automation, home control and automation, toys, games||Wireless LAN connectivity, broadband Internet access||Wireless connectivity between devices such as phones, PDA, laptops, headsets|
— Wi-Fi, Zigbee and Bluetooth comp...