Mai LED ne?

Za a LED?

Takardarwa ta LED

LED (Light Emitting Diode) shine wuri mai sauƙi da ya sauna tushen kasa idan yana gudanar da tsari. A cikin tattalin LED da suka fi sani, an yi amfani da gallium arsenide phosphide (GaAsP), gallium phosphide (GaP), da aluminum gallium arsenide (AlGaAs).LED sun samun tushen kasa tun daga alamar electroluminescence, wanda yake faru idan tsari mai tsari yana gudanar da kristal mai sauƙi da PN junction.

Amfani da abubuwa daga rukunin III da V na takardar jami'a. Idan a yi amfani da tsari mai tsari (IF), za a yi amfani da p-n junction don samun tushen kasa a ziyartar lambobin active region (Eg).

Yadda LED Ya Sha'awa

Idan a yi amfani da tsari mai tsari (IF) a kan p-n junction, za a shafi electron da ke nuna a p-region da kuma electron da ke nuna a n-region. Samun tushen kasa yana faru saboda recombination da ke faru a p-region.

Lambobi da ke faru a kan energy gap, ake kira radiative recombinations, sun samun photons (ya'ni tushen kasa), sannan non-radiative recombinations, sun samun phonons (ya'ni kasa). Tabbacin luminous efficacies da AlInGaP LEDs da InGaN LEDs masu peak wavelengths sun bayyana a tabbacin da aka bayyana.

Efficacy ta LED yana kasance saboda tushen kasa da ke faru a junction da kuma losses da ke faru a kan re-absorption idan tushen kasa ta fito daga kristal. Saboda refraction index mai yawa da ke cikin semiconductors, yawan tushen kasa take fito ne da ke faru a kristal, kuma yana hada da intensiti ta idan ta fito. Efficacy ta ke faru a kan visible energy ta ake kira external efficacy.

Alamomin electroluminescence sun samun faru a shekarar 1923 a cikin junctions na gida, amma ba a yi amfani da shi ba saboda haka da low luminous efficacy. Amma a yanzu efficacy ta ya zama mai yawa da kuma LEDs sun amfani a cikin signals, indicators, signs, displays, indoor lighting applications, da kuma road lighting applications.

Ruhun LED

Ruhun LED device yana bayyana a cikin dominant wavelength emitted, λd (a nanometers). AlInGaP LEDs sun samun ruhun red (626 to 630 nm), red-orange (615 to 621 nm), orange (605 nm), and amber (590 to 592 nm). InGaN LEDs sun samun ruhun green (525 nm), blue green (498 to 505 nm), and blue (470 nm). Ruhun da kuma forward voltage ta AlInGaP LEDs suna da iya da temperature ta p-n junction.

Idan temperature ta p-n junction ya zama mai yawa, za a samun luminous intensity mai yawa, dominant wavelength za a rubuta zuwa wavelengths masu yawan lambobi, da kuma forward voltage za a rubuta zuwa maya. Variations a cikin luminous intensity ta InGaN LEDs da operating ambient temperature suna da iya da 10% daga − 20°C zuwa 80°C. Amma, dominant wavelength ta InGaN LEDs suna da iya da LED drive current; idan LED drive current ya zama mai yawa, dominant wavelength za a rubuta zuwa wavelengths masu yawan lambobi.

Idan kana son amfani da colored LEDs a kan electronics project, best Arduino starter kits sun samun variety of colored LEDs.

Dimming

LEDs suna dimming don samun 10% daga rated light output ta da kuma reduce drive current. LEDs suna dimming a cikin Pulse Width Modulation techniques.

Reliability

Maximum junction temperature (TJMAX) shine muhimmiyar wajen LED’s longevity. Idan ta bincike wannan temperature, za a shafi encapsulated device. LED lifespan yana bayyana a cikin Mean Time Between Failures (MTBF), ake kula a testing numerous LEDs a standard current and temperature har zuwa half fail.

White LEDs

A yanzu ana yi amfani da white LEDs da kuma two methods: A cikin first method, red, green, and blue LED chips suna yi amfani a same package don samun white light; a cikin second method, phosphorescence suna amfani. Fluorescence a cikin phosphor da ke cikin epoxy surrounding the LED chip yana faru saboda short-wavelength energy from the InGaN LED device.

Luminous Efficacy

Luminous efficacy ta LED yana bayyana a cikin emitted luminous flux (a lm) per unit electrical power consumed (a W). Blue LEDs suna da rated internal efficacy a cikin 75 lm/W; red LEDs, approximately 155 lm/W; and amber LEDs, 500 lm/W. Taking into consideration losses due to internal re-absorption, the luminous efficacy is on the order of 20 to 25 lm/W for amber and green LEDs. This definition of efficacy is called external efficacy and is analogous to the definition of efficacy typically used for other light source types.