Editing Light-emitting diode (section)

==Types==
[[File:Verschiedene LEDs.jpg|thumb|LEDs are produced in a variety of shapes and sizes. The color of the plastic lens is often the same as the actual color of light emitted, but not always. For instance, purple plastic is often used for infrared LEDs, and most blue devices have colorless housings. Modern high-power LEDs such as those used for lighting and backlighting are generally found in [[surface-mount technology]] (SMT) packages (not shown).|397x397px]]
[[File:LED Rainbow Pack - 5mm PTH 12903-01 new aranged.jpg|thumb|upright|A variety of different diffused 5&nbsp;mm [[through-hole|THT]]-LEDs{{bulleted list|
| Red, 650 – 625nm
| Orange, 600 – 610nm
| Yellow, 587 – 591nm
| Green, 570 – 575nm
| Blue, 465 – 467nm
| Purple, 395 – 400nm}}]]

LEDs are made in different packages for different applications. A single or a few LED junctions may be packed in one miniature device for use as an indicator or pilot lamp. An LED array may include controlling circuits within the same package, which may range from a simple [[resistor]], blinking or color changing control, or an addressable controller for RGB devices. Higher-powered white-emitting devices will be mounted on heat sinks and will be used for illumination. Alphanumeric displays in dot matrix or bar formats are widely available. Special packages permit connection of LEDs to optical fibers for high-speed data communication links.

===Miniature===
[[File:Single and multicolor surface mount miniature LEDs in most common sizes.jpg|thumb|Image of miniature [[SMD LED|surface mount LED]]s in most common sizes. They can be much smaller than a traditional 5{{nbsp}}mm lamp type LED, shown on the upper left corner.]]
[[File:Very small 1.6x1.6x0.35 mm RGB Surface Mount LED EAST1616RGBA2.jpg|thumb|Very small (1.6×1.6×0.35{{nbsp}}mm) red, green, and blue surface mount miniature LED package with gold [[wire bonding]] details]]

These are mostly single-die LEDs used as indicators, and they come in various sizes from 1.8&nbsp;mm to 10&nbsp;mm, [[through-hole]] and [[surface mount]] packages.<ref>[http://www.elektor.com/magazines/2008/february/power-to-the-leds.350167.lynkx LED-design]. Elektor.com. Retrieved on March 16, 2012. {{webarchive |url=https://web.archive.org/web/20120831112624/http://www.elektor.com/magazines/2008/february/power-to-the-leds.350167.lynkx |date=August 31, 2012 }}</ref> Typical current ratings range from around 1&nbsp;mA to above 20&nbsp;mA. LED's can be soldered to a flexible PCB strip to form LED tape popularly used for decoration.

Common package shapes include round, with a domed or flat top, rectangular with a flat top (as used in bar-graph displays), and triangular or square with a flat top. The encapsulation may also be clear or tinted to improve contrast and viewing angle. Infrared devices may have a black tint to block visible light while passing infrared radiation, such as the Osram SFH 4546.<ref>{{Cite web |title=OSRAM Radial T1 3/4, SFH 4546 IR LEDs - ams-osram - ams |url=https://ams-osram.com/products/leds/ir-leds/osram-radial-t1-34-sfh-4546 |access-date=2024-09-19 |website=ams-osram |language=en-US}}</ref>

5&nbsp;V and 12&nbsp;V LEDs are ordinary miniature LEDs that have a series resistor for direct connection to a 5{{nbsp}}V or 12{{nbsp}}V supply.<ref>{{Cite web |title=LED Through Hole 5mm (T-1 3/4) Red Built-in resistor 635 nm 4500 mcd 12V |url=https://vcclite.com/product/lth5mm12vfr4100/ |access-date=2024-09-19 |website=VCC |language=en-US}}</ref>

===High-power===
[[File:2007-07-24 High-power light emitting diodes (Luxeon, Lumiled).jpg|thumb|High-power light-emitting diodes attached to an LED star base ([[Luxeon]], [[Philips Lumileds Lighting Company|Lumileds]])]]
{{See also|Solid-state lighting|LED lamp|Thermal management of high-power LEDs}}

High-power LEDs (HP-LEDs) or high-output LEDs (HO-LEDs) can be driven at currents from hundreds of mA to more than an ampere, compared with the tens of mA for other LEDs. Some can emit over a thousand lumens.<ref>{{cite web |url=http://www.luminus.com/content1044|archive-url=https://web.archive.org/web/20080725033952/http://www.luminus.com/content1044 |archive-date=2008-07-25 |title=Luminus Products |publisher=Luminus Devices |access-date=October 21, 2009}}</ref><ref>{{cite web |url=http://www.luminus.com/stuff/contentmgr/files/0/7c8547b3575bcecc577525b80d210ac7/misc/pds_001314_rev_03__cst_90_w_product_datasheet_illumination.pdf |archive-url=https://web.archive.org/web/20100331100545/http://www.luminus.com/stuff/contentmgr/files/0/7c8547b3575bcecc577525b80d210ac7/misc/pds_001314_rev_03__cst_90_w_product_datasheet_illumination.pdf |archive-date=2010-03-31 |title=Luminus Products CST-90 Series Datasheet |publisher=Luminus Devices |access-date=2009-10-25}}</ref> LED [[Power density|power densities]] up to 300 W/cm<sup>2</sup> have been achieved. Since overheating is destructive, the HP-LEDs must be mounted on a heat sink to allow for heat dissipation. If the heat from an HP-LED is not removed, the device fails in seconds. One HP-LED can often replace an incandescent bulb in a [[flashlight]], or be set in an array to form a powerful [[LED lamp]].

Some HP-LEDs in this category are the [[Nichia]] 19 series, [[Lumileds]] Rebel Led, Osram Opto Semiconductors Golden Dragon, and Cree X-lamp. As of September 2009, some HP-LEDs manufactured by Cree exceed 105&nbsp;lm/W.<ref name="Xlamp Xp-G Led">{{cite web |url=http://www.cree.com/products/xlamp_xpg.asp |title=Xlamp Xp-G Led |website=Cree.com |publisher=[[Cree, Inc.]] |access-date=2012-03-16 |url-status=dead |archive-url=https://web.archive.org/web/20120313082324/http://www.cree.com/products/xlamp_xpg.asp |archive-date=2012-03-13 }}</ref>

Examples for [[Haitz's law]]—which predicts an exponential rise in light output and efficacy of LEDs over time—are the CREE XP-G series LED, which achieved 105{{nbsp}}lm/W in 2009<ref name="Xlamp Xp-G Led" /> and the Nichia 19 series with a typical efficacy of 140{{nbsp}}lm/W, released in 2010.<ref>[http://www.nichia.co.jp/en/about_nichia/2010/2010_110201.html High Power Point Source White Led NVSx219A] {{Webarchive|url=https://web.archive.org/web/20210729062935/https://www.nichia.co.jp/en/about_nichia/2010/2010_110201.html |date=July 29, 2021 }}. Nichia.co.jp, November 2, 2010.</ref>

===AC-driven===
LEDs developed by Seoul Semiconductor can operate on AC power without a DC converter. For each half-cycle, part of the LED emits light and part is dark, and this is reversed during the next half-cycle. The efficiency of this type of HP-LED is typically 40{{nbsp}}lm/W.<ref>{{cite web|url=http://www.ledsmagazine.com/news/3/11/14|title=Seoul Semiconductor launches AC LED lighting source Acrich|publisher=LEDS Magazine|access-date=February 17, 2008|date=November 17, 2006|archive-date=October 15, 2007|archive-url=https://web.archive.org/web/20071015021634/http://www.ledsmagazine.com/news/3/11/14|url-status=dead}}</ref> A large number of LED elements in series may be able to operate directly from line voltage. In 2009, Seoul Semiconductor released a high DC voltage LED, named 'Acrich MJT', capable of being driven from AC power with a simple controlling circuit. The low-power dissipation of these LEDs affords them more flexibility than the original AC LED design.<ref name="IDA" />

===Strip===
{{excerpt|LED strip light}}There are many types of LED Strips each with different codenames and LED types. Each one can vary in input power, led spacing, color capability and more.

=== Application-specific ===
{{more citations needed|section|date=October 2020}}
[[File:RGB-SMD-LED.jpg|thumb|RGB-SMD-LED]]
[[File:Macro photo of LED matrix.jpg|thumb|upright|Composite image of an {{nowrap|11 × 44}} LED matrix lapel [[name tag]] display using 1608/0603-type SMD LEDs. Top: A little over half of the {{nowrap|21 × 86 mm}} display. Center: Close-up of LEDs in ambient light. Bottom: LEDs in their own red light.]]
; Flashing: Flashing LEDs are used as attention seeking indicators without requiring external electronics. Flashing LEDs resemble standard LEDs but they contain an integrated [[voltage regulator]] and a [[multivibrator]] circuit that causes the LED to flash with a typical period of one second. In diffused lens LEDs, this circuit is visible as a small black dot. Most flashing LEDs emit light of one color, but more sophisticated devices can flash between multiple colors and even fade through a color sequence using RGB color mixing. Flashing SMD LEDs in the 0805 and other size formats have been available since early 2019.
; Flickering: [[File:IR-Led-Die.jpg|thumb|Infrared light from the LED die of IR LED as seen by a digital camera]]Simple electronic circuits integrated into the LED package have been around since at least 2011 which produce a random LED intensity pattern reminiscent of a flickering [[candle]].<ref>{{Cite web |last=Oskay |first=Windell |date=2011-06-22 |title=Does this LED sound funny to you? |url=https://www.evilmadscientist.com/2011/does-this-led-sound-funny-to-you/ |url-status=live |archive-url=https://web.archive.org/web/20230924100327/https://www.evilmadscientist.com/2011/does-this-led-sound-funny-to-you/ |archive-date=2023-09-24 |access-date=2024-01-30 |website=Evil Mad Scientist Laboratories |language=en-US}}</ref> [[Reverse engineering]] in 2024 has suggested that some flickering LEDs with automatic sleep and wake modes might be using an integrated [[8-bit computing|8-bit]] [[microcontroller]] for such functionally.<ref>{{Cite web |last=Tim's Blog |date=2024-01-14 |title=Revisiting Candle Flicker-LEDs: Now with integrated Timer |url=https://cpldcpu.wordpress.com/2024/01/14/revisiting-candle-flicker-leds-now-with-integrated-timer/ |url-status=live |archive-url=https://web.archive.org/web/20240129164612/https://cpldcpu.wordpress.com/2024/01/14/revisiting-candle-flicker-leds-now-with-integrated-timer/ |archive-date=2024-01-29 |access-date=2024-01-30 |website=cpldcpu.wordpress.com |language=en}}</ref> Sometimes a flickering effect might happen due to an electric malfunction.<ref>{{Cite web |date=2025-03-06 |title=What Can Cause Room Light to Flicker? |url=https://comiled.com/blogs/news/what-can-cause-room-light-to-flicker |access-date=2025-04-16 |website=ComiLED |language=en}}</ref>
; Bi-color: Bi-color LEDs contain two different LED emitters in one case. There are two types of these. One type consists of two dies connected to the same two leads [[Antiparallel (electronics)|antiparallel]] to each other. Current flow in one direction emits one color, and current in the opposite direction emits the other color. The other type consists of two dies with separate leads for both dies and another lead for common anode or cathode so that they can be controlled independently. The most common bi-color combination is [[RG color space|red/traditional green]]. Others include amber/traditional green, red/pure green, red/blue, and blue/pure green.
; RGB tri-color: Tri-color LEDs contain three different LED emitters in one case. Each emitter is connected to a separate lead so they can be controlled independently. A four-lead arrangement is typical with one common lead (anode or cathode) and an additional lead for each color. Others have only two leads (positive and negative) and have a built-in electronic controller. [[RGB color model|RGB]] LEDs consist of one red, one green, and one blue LED.<ref>{{Cite book |url=https://books.google.com/books?id=qk1hmpEQVxIC&pg=PA349 |title=5th Kuala Lumpur International Conference on Biomedical Engineering 2011: BIOMED 2011, 20–23 June 2011, Kuala Lumpur, Malaysia |last=Ting |first=Hua-Nong |date=2011-06-17|publisher=Springer Science & Business Media |isbn=9783642217296}}</ref> By independently [[pulse-width modulation|adjusting]] each of the three, RGB LEDs are capable of producing a wide color gamut. Unlike dedicated-color LEDs, these do not produce pure wavelengths. Modules may not be optimized for smooth color mixing.
; Decorative-multicolor: Decorative-multicolor LEDs incorporate several emitters of different colors supplied by only two lead-out wires. Colors are switched internally by varying the supply voltage.
; Alphanumeric: Alphanumeric LEDs are available in [[seven-segment display|seven-segment]], [[Starburst display|starburst]], and [[Dot-matrix display|dot-matrix]] format. Seven-segment displays handle all numbers and a limited set of letters. Starburst displays can display all letters. Dot-matrix displays typically use 5×7 pixels per character. Seven-segment LED displays were in widespread use in the 1970s and 1980s, but rising use of [[liquid crystal display]]s, with their lower power needs and greater display flexibility, has reduced the popularity of numeric and alphanumeric LED displays.
; Digital RGB: Digital RGB addressable LEDs contain their own "smart" control electronics. In addition to power and ground, these provide connections for data-in, data-out, clock and sometimes a strobe signal. These are connected in a [[Daisy chain (electrical engineering)|daisy chain]], which allows individual LEDs in a long [[LED strip light]] to be easily controlled by a microcontroller. Data sent to the first LED of the chain can control the brightness and color of each LED independently of the others. They are used where a combination of maximum control and minimum visible electronics are needed such as strings for Christmas and LED matrices. Some even have refresh rates in the kHz range, allowing for basic video applications. These devices are known by their part number ([https://cdn-shop.adafruit.com/datasheets/WS2812.pdf WS2812] being common) or a brand name such as [[Adafruit Industries#NeoPixel|NeoPixel]].
; Filament: An [[LED filament]] consists of multiple LED chips connected in series on a common longitudinal substrate that forms a thin rod reminiscent of a traditional incandescent filament.<ref>{{cite web|url=http://www.ledinside.com/knowledge/2015/2/the_next_generation_of_led_filament_bulbs|title=The Next Generation of LED Filament Bulbs|website=LEDInside.com|publisher=Trendforce|access-date=October 26, 2015}}</ref> These are being used as a low-cost decorative alternative for traditional light bulbs that are being phased out in many countries. The filaments use a rather high voltage, allowing them to work efficiently with mains voltages. Often a simple rectifier and capacitive current limiting are employed to create a low-cost replacement for a traditional light bulb without the complexity of the low voltage, high current converter that single die LEDs need.<ref>Archived at [https://ghostarchive.org/varchive/youtube/20211211/H_XiunR-cAQ Ghostarchive]{{cbignore}} and the {{usurped|1=[https://web.archive.org/web/20151122213511/https://www.youtube.com/watch?v=H_XiunR-cAQ Wayback Machine]}}{{cbignore}}: {{cite web|url=https://www.youtube.com/watch?v=H_XiunR-cAQ|title=LED Filaments|website=[[YouTube]]|date=April 5, 2015 |access-date=October 26, 2015}}{{cbignore}}</ref> Usually, they are packaged in bulb similar to the lamps they were designed to replace, and filled with inert gas at slightly lower than ambient pressure to remove heat efficiently and prevent corrosion.
; Chip-on-board arrays: Surface-mounted LEDs are frequently produced in [[chip on board]] (COB) arrays, allowing better heat dissipation than with a single LED of comparable luminous output.<ref>{{cite book|title=Handbook on the Physics and Chemistry of Rare Earths: Including Actinides|url=https://books.google.com/books?id=lO_lCgAAQBAJ&pg=PA89|date=1 August 2016|publisher=Elsevier Science|isbn=978-0-444-63705-5|page=89}}</ref> The LEDs can be arranged around a cylinder, and are called "corn cob lights" because of the rows of yellow LEDs.<ref>{{cite web |title=Corn Lamps: What Are They & Where Can I Use Them? |date=September 1, 2016 |publisher=Shine Retrofits |url=https://www.shineretrofits.com/lighting-center/corn-lamps |access-date=December 30, 2018}}</ref>