id stringlengths 24 24 | question stringlengths 1 270 | answer stringlengths 1 239 | documents listlengths 1 1 |
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5731162005b4da19006bcd7e | Higher efficiency in multi-color white LEDs may mean what? | lower color rendering | [
"Light-emitting_diode\n\nThere are several types of multi-color white LEDs: di-, tri-, and tetrachromatic white LEDs. Several key factors that play among these different methods, include color stability, color rendering capability, and luminous efficacy. Often, higher efficiency will mean lower color rendering, pre... |
5731162005b4da19006bcd7f | What type has the best luminous efficacy? | dichromatic white LEDs | [
"Light-emitting_diode\n\nThere are several types of multi-color white LEDs: di-, tri-, and tetrachromatic white LEDs. Several key factors that play among these different methods, include color stability, color rendering capability, and luminous efficacy. Often, higher efficiency will mean lower color rendering, pre... |
5731162005b4da19006bcd80 | What luminous efficacy does trichromatic white LEDs have? | >70 lm/W | [
"Light-emitting_diode\n\nThere are several types of multi-color white LEDs: di-, tri-, and tetrachromatic white LEDs. Several key factors that play among these different methods, include color stability, color rendering capability, and luminous efficacy. Often, higher efficiency will mean lower color rendering, pre... |
57311c03e6313a140071cc44 | Multi-color LEDs offer what else besides the formation of white light? | to form light of different colors | [
"Light-emitting_diode\n\nMulti-color LEDs offer not merely another means to form white light but a new means to form light of different colors. Most perceivable colors can be formed by mixing different amounts of three primary colors. This allows precise dynamic color control. As more effort is devoted to investiga... |
57311c03e6313a140071cc45 | What problem must be solved before multi-color LEDs can play a role in the market? | power decays exponentially with rising temperature | [
"Light-emitting_diode\n\nMulti-color LEDs offer not merely another means to form white light but a new means to form light of different colors. Most perceivable colors can be formed by mixing different amounts of three primary colors. This allows precise dynamic color control. As more effort is devoted to investiga... |
57311c03e6313a140071cc46 | What problem results when rising temperatures decays power? | substantial change in color stability | [
"Light-emitting_diode\n\nMulti-color LEDs offer not merely another means to form white light but a new means to form light of different colors. Most perceivable colors can be formed by mixing different amounts of three primary colors. This allows precise dynamic color control. As more effort is devoted to investiga... |
57311e4ca5e9cc1400cdbc3f | What method involves coating LEDs of one color with phosphors of different colors? | phosphor-converted white LEDs (pcLEDs) | [
"Light-emitting_diode\n\nThis method involves coating LEDs of one color (mostly blue LEDs made of InGaN) with phosphors of different colors to form white light; the resultant LEDs are called phosphor-based or phosphor-converted white LEDs (pcLEDs). A fraction of the blue light undergoes the Stokes shift being trans... |
57311e4ca5e9cc1400cdbc40 | In pcLEDs method, a fraction of what light is used? | blue | [
"Light-emitting_diode\n\nThis method involves coating LEDs of one color (mostly blue LEDs made of InGaN) with phosphors of different colors to form white light; the resultant LEDs are called phosphor-based or phosphor-converted white LEDs (pcLEDs). A fraction of the blue light undergoes the Stokes shift being trans... |
57311e4ca5e9cc1400cdbc41 | What shift does blue light undergo in the pcLEDs method? | Stokes | [
"Light-emitting_diode\n\nThis method involves coating LEDs of one color (mostly blue LEDs made of InGaN) with phosphors of different colors to form white light; the resultant LEDs are called phosphor-based or phosphor-converted white LEDs (pcLEDs). A fraction of the blue light undergoes the Stokes shift being trans... |
57311e4ca5e9cc1400cdbc42 | The different colors of phosphors that can be used is based on what? | the color of the original LED | [
"Light-emitting_diode\n\nThis method involves coating LEDs of one color (mostly blue LEDs made of InGaN) with phosphors of different colors to form white light; the resultant LEDs are called phosphor-based or phosphor-converted white LEDs (pcLEDs). A fraction of the blue light undergoes the Stokes shift being trans... |
57311e4ca5e9cc1400cdbc43 | What broadens the emitted spectrum in a pcLEDs method? | If several phosphor layers of distinct colors are applied | [
"Light-emitting_diode\n\nThis method involves coating LEDs of one color (mostly blue LEDs made of InGaN) with phosphors of different colors to form white light; the resultant LEDs are called phosphor-based or phosphor-converted white LEDs (pcLEDs). A fraction of the blue light undergoes the Stokes shift being trans... |
57311faae6313a140071cc50 | Why is efficiency sometimes lost in phosphor-based LEDs? | heat loss from the Stokes shift | [
"Light-emitting_diode\n\nPhosphor-based LED efficiency losses are due to the heat loss from the Stokes shift and also other phosphor-related degradation issues. Their luminous efficacies compared to normal LEDs depend on the spectral distribution of the resultant light output and the original wavelength of the LED ... |
57311faae6313a140071cc51 | What do phosphor-based LEDs luminous efficacies depend on? | the spectral distribution of the resultant light output | [
"Light-emitting_diode\n\nPhosphor-based LED efficiency losses are due to the heat loss from the Stokes shift and also other phosphor-related degradation issues. Their luminous efficacies compared to normal LEDs depend on the spectral distribution of the resultant light output and the original wavelength of the LED ... |
57311faae6313a140071cc52 | What are some of the luminous efficacies of yellow phosphor based white LED compared to blue? | 3 to 5 times the luminous efficacy | [
"Light-emitting_diode\n\nPhosphor-based LED efficiency losses are due to the heat loss from the Stokes shift and also other phosphor-related degradation issues. Their luminous efficacies compared to normal LEDs depend on the spectral distribution of the resultant light output and the original wavelength of the LED ... |
57311faae6313a140071cc53 | What is the most popular method for making high-intensity white LEDs? | phosphor method | [
"Light-emitting_diode\n\nPhosphor-based LED efficiency losses are due to the heat loss from the Stokes shift and also other phosphor-related degradation issues. Their luminous efficacies compared to normal LEDs depend on the spectral distribution of the resultant light output and the original wavelength of the LED ... |
57311faae6313a140071cc54 | What type of emitter is used in phosphor-based white LED methods? | monochrome | [
"Light-emitting_diode\n\nPhosphor-based LED efficiency losses are due to the heat loss from the Stokes shift and also other phosphor-related degradation issues. Their luminous efficacies compared to normal LEDs depend on the spectral distribution of the resultant light output and the original wavelength of the LED ... |
5731208ee6313a140071cc62 | What can improve the efficiency of LED-based white light? | more efficient phosphors | [
"Light-emitting_diode\n\nAmong the challenges being faced to improve the efficiency of LED-based white light sources is the development of more efficient phosphors. As of 2010, the most efficient yellow phosphor is still the YAG phosphor, with less than 10% Stoke shift loss. Losses attributable to internal optical ... |
5731208ee6313a140071cc63 | What is the most efficient yellow phosphor? | YAG phosphor | [
"Light-emitting_diode\n\nAmong the challenges being faced to improve the efficiency of LED-based white light sources is the development of more efficient phosphors. As of 2010, the most efficient yellow phosphor is still the YAG phosphor, with less than 10% Stoke shift loss. Losses attributable to internal optical ... |
5731208ee6313a140071cc64 | What is the percentage of stoke shift loss in YAG phosphor? | less than 10% | [
"Light-emitting_diode\n\nAmong the challenges being faced to improve the efficiency of LED-based white light sources is the development of more efficient phosphors. As of 2010, the most efficient yellow phosphor is still the YAG phosphor, with less than 10% Stoke shift loss. Losses attributable to internal optical ... |
5731208ee6313a140071cc65 | What area are scientists looking into regarding phosphor LED development? | higher operation temperatures | [
"Light-emitting_diode\n\nAmong the challenges being faced to improve the efficiency of LED-based white light sources is the development of more efficient phosphors. As of 2010, the most efficient yellow phosphor is still the YAG phosphor, with less than 10% Stoke shift loss. Losses attributable to internal optical ... |
5731208ee6313a140071cc66 | What is one method that can raise the efficiency of phosphor-based LEDs? | adapting better package design | [
"Light-emitting_diode\n\nAmong the challenges being faced to improve the efficiency of LED-based white light sources is the development of more efficient phosphors. As of 2010, the most efficient yellow phosphor is still the YAG phosphor, with less than 10% Stoke shift loss. Losses attributable to internal optical ... |
57312247497a881900248b87 | White LEDs can be made by coating what? | near-ultraviolet (NUV) LEDs | [
"Light-emitting_diode\n\nWhite LEDs can also be made by coating near-ultraviolet (NUV) LEDs with a mixture of high-efficiency europium-based phosphors that emit red and blue, plus copper and aluminium-doped zinc sulfide (ZnS:Cu, Al) that emits green. This is a method analogous to the way fluorescent lamps work. Thi... |
57312247497a881900248b88 | What are near-ultraviolet LEDs coated with to create white LED? | copper and aluminium-doped zinc sulfide (ZnS:Cu, Al) | [
"Light-emitting_diode\n\nWhite LEDs can also be made by coating near-ultraviolet (NUV) LEDs with a mixture of high-efficiency europium-based phosphors that emit red and blue, plus copper and aluminium-doped zinc sulfide (ZnS:Cu, Al) that emits green. This is a method analogous to the way fluorescent lamps work. Thi... |
57312247497a881900248b89 | What device also works in a similar way as NUV LEDs? | fluorescent lamps | [
"Light-emitting_diode\n\nWhite LEDs can also be made by coating near-ultraviolet (NUV) LEDs with a mixture of high-efficiency europium-based phosphors that emit red and blue, plus copper and aluminium-doped zinc sulfide (ZnS:Cu, Al) that emits green. This is a method analogous to the way fluorescent lamps work. Thi... |
57312247497a881900248b8a | The method of coating NUVs less efficient than what other LEDs? | blue | [
"Light-emitting_diode\n\nWhite LEDs can also be made by coating near-ultraviolet (NUV) LEDs with a mixture of high-efficiency europium-based phosphors that emit red and blue, plus copper and aluminium-doped zinc sulfide (ZnS:Cu, Al) that emits green. This is a method analogous to the way fluorescent lamps work. Thi... |
57312247497a881900248b8b | What light can harm human eyes or skin? | UV light | [
"Light-emitting_diode\n\nWhite LEDs can also be made by coating near-ultraviolet (NUV) LEDs with a mixture of high-efficiency europium-based phosphors that emit red and blue, plus copper and aluminium-doped zinc sulfide (ZnS:Cu, Al) that emits green. This is a method analogous to the way fluorescent lamps work. Thi... |
5731234a497a881900248b91 | What is being used to produce white LEDs? | wafers composed of gallium-nitride-on-silicon | [
"Light-emitting_diode\n\nA new style of wafers composed of gallium-nitride-on-silicon (GaN-on-Si) is being used to produce white LEDs using 200-mm silicon wafers. This avoids the typical costly sapphire substrate in relatively small 100- or 150-mm wafer sizes. The sapphire apparatus must be coupled with a mirror-li... |
5731234a497a881900248b92 | What size are the wafers used to create white LEDs? | 200-mm | [
"Light-emitting_diode\n\nA new style of wafers composed of gallium-nitride-on-silicon (GaN-on-Si) is being used to produce white LEDs using 200-mm silicon wafers. This avoids the typical costly sapphire substrate in relatively small 100- or 150-mm wafer sizes. The sapphire apparatus must be coupled with a mirror-li... |
5731234a497a881900248b93 | By using silicon wafers, what is being avoided? | costly sapphire substrate | [
"Light-emitting_diode\n\nA new style of wafers composed of gallium-nitride-on-silicon (GaN-on-Si) is being used to produce white LEDs using 200-mm silicon wafers. This avoids the typical costly sapphire substrate in relatively small 100- or 150-mm wafer sizes. The sapphire apparatus must be coupled with a mirror-li... |
5731234a497a881900248b94 | What needs to be used to reflect light that would otherwise be wasted? | mirror-like collector | [
"Light-emitting_diode\n\nA new style of wafers composed of gallium-nitride-on-silicon (GaN-on-Si) is being used to produce white LEDs using 200-mm silicon wafers. This avoids the typical costly sapphire substrate in relatively small 100- or 150-mm wafer sizes. The sapphire apparatus must be coupled with a mirror-li... |
5731234a497a881900248b95 | By what year will% of all GaN LEDs be made with gallium-nitride-on-silicon wafers? | 2020 | [
"Light-emitting_diode\n\nA new style of wafers composed of gallium-nitride-on-silicon (GaN-on-Si) is being used to produce white LEDs using 200-mm silicon wafers. This avoids the typical costly sapphire substrate in relatively small 100- or 150-mm wafer sizes. The sapphire apparatus must be coupled with a mirror-li... |
5731249ea5e9cc1400cdbc9b | What nanocrystals possess unique optical properties? | Quantum dots | [
"Light-emitting_diode\n\nQuantum dots (QD) are semiconductor nanocrystals that possess unique optical properties. Their emission color can be tuned from the visible throughout the infrared spectrum. This allows quantum dot LEDs to create almost any color on the CIE diagram. This provides more color options and bett... |
5731249ea5e9cc1400cdbc9c | Quantum Dot LEDs can do what special skill? | create almost any color on the CIE diagram | [
"Light-emitting_diode\n\nQuantum dots (QD) are semiconductor nanocrystals that possess unique optical properties. Their emission color can be tuned from the visible throughout the infrared spectrum. This allows quantum dot LEDs to create almost any color on the CIE diagram. This provides more color options and bett... |
5731249ea5e9cc1400cdbc9d | The narrowing of the emission spectrum in Quantum Dot LEDs allows them to do what? | better color rendering | [
"Light-emitting_diode\n\nQuantum dots (QD) are semiconductor nanocrystals that possess unique optical properties. Their emission color can be tuned from the visible throughout the infrared spectrum. This allows quantum dot LEDs to create almost any color on the CIE diagram. This provides more color options and bett... |
5731249ea5e9cc1400cdbc9e | How many types of schemes are there in Quantum Dot LED excitation? | two | [
"Light-emitting_diode\n\nQuantum dots (QD) are semiconductor nanocrystals that possess unique optical properties. Their emission color can be tuned from the visible throughout the infrared spectrum. This allows quantum dot LEDs to create almost any color on the CIE diagram. This provides more color options and bett... |
573125ee497a881900248bcb | What is one scheme of Quantum Dot excitation? | electrical-excitation | [
"Light-emitting_diode\n\nThe structure of QD-LEDs used for the electrical-excitation scheme is similar to basic design of OLEDs. A layer of quantum dots is sandwiched between layers of electron-transporting and hole-transporting materials. An applied electric field causes electrons and holes to move into the quantu... |
573125ee497a881900248bcc | What is one material used in electrical-excitation? | hole-transporting materials | [
"Light-emitting_diode\n\nThe structure of QD-LEDs used for the electrical-excitation scheme is similar to basic design of OLEDs. A layer of quantum dots is sandwiched between layers of electron-transporting and hole-transporting materials. An applied electric field causes electrons and holes to move into the quantu... |
573125ee497a881900248bcd | During the electrical-excitation scheme, what moves into the quantum dot layer? | electrons and holes | [
"Light-emitting_diode\n\nThe structure of QD-LEDs used for the electrical-excitation scheme is similar to basic design of OLEDs. A layer of quantum dots is sandwiched between layers of electron-transporting and hole-transporting materials. An applied electric field causes electrons and holes to move into the quantu... |
573125ee497a881900248bce | A Quantum Dot LED has been used in what? | near-field scanning optical microscopy (NSOM) | [
"Light-emitting_diode\n\nThe structure of QD-LEDs used for the electrical-excitation scheme is similar to basic design of OLEDs. A layer of quantum dots is sandwiched between layers of electron-transporting and hole-transporting materials. An applied electric field causes electrons and holes to move into the quantu... |
5731304e497a881900248c37 | How many lumens can some high-power LEDs emit? | over a thousand | [
"Light-emitting_diode\n\nHigh-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. LED power densities up to 300 W/cm2 have been achieved. Since overheating is destr... |
5731304e497a881900248c38 | Up to how many densities have been achieved with LED power? | 300 W/cm2 | [
"Light-emitting_diode\n\nHigh-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. LED power densities up to 300 W/cm2 have been achieved. Since overheating is destr... |
5731304e497a881900248c39 | Why must High-power LEDs be mounted on a heat sink? | to allow for heat dissipation | [
"Light-emitting_diode\n\nHigh-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. LED power densities up to 300 W/cm2 have been achieved. Since overheating is destr... |
5731304e497a881900248c3a | What will happen if the heat from a high-power LED is not removed? | the device will fail in seconds | [
"Light-emitting_diode\n\nHigh-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. LED power densities up to 300 W/cm2 have been achieved. Since overheating is destr... |
5731304e497a881900248c3b | What can one high-power LED replace? | incandescent bulb in a flashlight | [
"Light-emitting_diode\n\nHigh-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. LED power densities up to 300 W/cm2 have been achieved. Since overheating is destr... |
57313224e6313a140071ccee | What company has developed LEDs that can operate on AC power? | Seoul Semiconductor | [
"Light-emitting_diode\n\nLEDs have been developed by Seoul Semiconductor that can operate on AC power without the need for 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 efficacy of this type of HP-LED is typically 40 lm/W. A l... |
57313224e6313a140071ccef | What is the efficacy of an AC powered HP-LED? | 40 lm/W | [
"Light-emitting_diode\n\nLEDs have been developed by Seoul Semiconductor that can operate on AC power without the need for 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 efficacy of this type of HP-LED is typically 40 lm/W. A l... |
57313224e6313a140071ccf0 | When did Seoul Semiconductor release the first high DC voltage LED? | 2009 | [
"Light-emitting_diode\n\nLEDs have been developed by Seoul Semiconductor that can operate on AC power without the need for 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 efficacy of this type of HP-LED is typically 40 lm/W. A l... |
57313224e6313a140071ccf1 | What is so good about ac powered HP-LEDs? | more flexibility | [
"Light-emitting_diode\n\nLEDs have been developed by Seoul Semiconductor that can operate on AC power without the need for 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 efficacy of this type of HP-LED is typically 40 lm/W. A l... |
57313224e6313a140071ccf2 | What did Seoul Semiconductor name their ac powered HP-LED? | Acrich MJT | [
"Light-emitting_diode\n\nLEDs have been developed by Seoul Semiconductor that can operate on AC power without the need for 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 efficacy of this type of HP-LED is typically 40 lm/W. A l... |
57313c12a5e9cc1400cdbd6b | What type of LEDs are available in seven-segment format? | Alphanumeric | [
"Light-emitting_diode\n\nAlphanumeric LEDs are available in seven-segment, starburst and 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 5x7 pixels per character. Seven-segment LED displays were ... |
57313c12a5e9cc1400cdbd6c | What is another format that Alphanumeric LEDs are available in? | dot-matrix | [
"Light-emitting_diode\n\nAlphanumeric LEDs are available in seven-segment, starburst and 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 5x7 pixels per character. Seven-segment LED displays were ... |
57313c12a5e9cc1400cdbd6d | Which alphanumeric LED display can display all letters? | Starburst | [
"Light-emitting_diode\n\nAlphanumeric LEDs are available in seven-segment, starburst and 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 5x7 pixels per character. Seven-segment LED displays were ... |
57313c12a5e9cc1400cdbd6e | What type of pixels does a dot matrix display use? | 5x7 | [
"Light-emitting_diode\n\nAlphanumeric LEDs are available in seven-segment, starburst and 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 5x7 pixels per character. Seven-segment LED displays were ... |
57313c12a5e9cc1400cdbd6f | What has reduced the popularity of numeric LED displays? | liquid crystal displays | [
"Light-emitting_diode\n\nAlphanumeric LEDs are available in seven-segment, starburst and 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 5x7 pixels per character. Seven-segment LED displays were ... |
57313d9505b4da19006bcf20 | What makes RGB LEDs different? | contain their own "smart" control electronics | [
"Light-emitting_diode\n\nDigital-RGB LEDs are RGB LEDs that contain their own \"smart\" control electronics. In addition to power and ground, these provide connections for data-in, data-out, and sometimes a clock or strobe signal. These are connected in a daisy chain, with the data in of the first LED sourced by a ... |
57313d9505b4da19006bcf21 | How are Digital-RGB LED strobe signals connected? | in a daisy chain | [
"Light-emitting_diode\n\nDigital-RGB LEDs are RGB LEDs that contain their own \"smart\" control electronics. In addition to power and ground, these provide connections for data-in, data-out, and sometimes a clock or strobe signal. These are connected in a daisy chain, with the data in of the first LED sourced by a ... |
57313d9505b4da19006bcf22 | What object sources the data in of the first LED of a digital rgb LED? | microprocessor | [
"Light-emitting_diode\n\nDigital-RGB LEDs are RGB LEDs that contain their own \"smart\" control electronics. In addition to power and ground, these provide connections for data-in, data-out, and sometimes a clock or strobe signal. These are connected in a daisy chain, with the data in of the first LED sourced by a ... |
57313d9505b4da19006bcf23 | The microprocessor does what in a digital RGB LED? | control the brightness and color of each LED independently of the others | [
"Light-emitting_diode\n\nDigital-RGB LEDs are RGB LEDs that contain their own \"smart\" control electronics. In addition to power and ground, these provide connections for data-in, data-out, and sometimes a clock or strobe signal. These are connected in a daisy chain, with the data in of the first LED sourced by a ... |
57313d9505b4da19006bcf24 | What is one example of where Digital RGB LED lights are used? | Christmas | [
"Light-emitting_diode\n\nDigital-RGB LEDs are RGB LEDs that contain their own \"smart\" control electronics. In addition to power and ground, these provide connections for data-in, data-out, and sometimes a clock or strobe signal. These are connected in a daisy chain, with the data in of the first LED sourced by a ... |
57313e89a5e9cc1400cdbda1 | What does an LED filament consist of? | multiple LED dice | [
"Light-emitting_diode\n\nAn LED filament consists of multiple LED dice connected in series on a common longitudinal substrate that form a thin rod reminiscent of a traditional incandescent filament. These are being used as a low cost decorative alternative for traditional light bulbs that are being phased out in ma... |
57313e89a5e9cc1400cdbda2 | How are LED filaments used? | a low cost decorative alternative for traditional light bulbs | [
"Light-emitting_diode\n\nAn LED filament consists of multiple LED dice connected in series on a common longitudinal substrate that form a thin rod reminiscent of a traditional incandescent filament. These are being used as a low cost decorative alternative for traditional light bulbs that are being phased out in ma... |
57313e89a5e9cc1400cdbda3 | What type of voltage is needed for LED filaments? | high | [
"Light-emitting_diode\n\nAn LED filament consists of multiple LED dice connected in series on a common longitudinal substrate that form a thin rod reminiscent of a traditional incandescent filament. These are being used as a low cost decorative alternative for traditional light bulbs that are being phased out in ma... |
57313e89a5e9cc1400cdbda4 | What helps LED filaments remain low cost? | a simple rectifier | [
"Light-emitting_diode\n\nAn LED filament consists of multiple LED dice connected in series on a common longitudinal substrate that form a thin rod reminiscent of a traditional incandescent filament. These are being used as a low cost decorative alternative for traditional light bulbs that are being phased out in ma... |
57313e89a5e9cc1400cdbda5 | Single die LEDs require what? | high current converter | [
"Light-emitting_diode\n\nAn LED filament consists of multiple LED dice connected in series on a common longitudinal substrate that form a thin rod reminiscent of a traditional incandescent filament. These are being used as a low cost decorative alternative for traditional light bulbs that are being phased out in ma... |
57313fb0497a881900248ce1 | How are LEDs similar to other diodes? | the current is dependent exponentially on the voltage | [
"Light-emitting_diode\n\nThe current–voltage characteristic of an LED is similar to other diodes, in that the current is dependent exponentially on the voltage (see Shockley diode equation). This means that a small change in voltage can cause a large change in current. If the applied voltage exceeds the LED's forwa... |
57313fb0497a881900248ce2 | What can cause a large change in current in LEDs? | a small change in voltage | [
"Light-emitting_diode\n\nThe current–voltage characteristic of an LED is similar to other diodes, in that the current is dependent exponentially on the voltage (see Shockley diode equation). This means that a small change in voltage can cause a large change in current. If the applied voltage exceeds the LED's forwa... |
57313fb0497a881900248ce3 | What is a solution to preventing an LED failure? | use constant-current power supplies | [
"Light-emitting_diode\n\nThe current–voltage characteristic of an LED is similar to other diodes, in that the current is dependent exponentially on the voltage (see Shockley diode equation). This means that a small change in voltage can cause a large change in current. If the applied voltage exceeds the LED's forwa... |
57313fb0497a881900248ce4 | What feature do most LED fixtures need to have? | a power converter | [
"Light-emitting_diode\n\nThe current–voltage characteristic of an LED is similar to other diodes, in that the current is dependent exponentially on the voltage (see Shockley diode equation). This means that a small change in voltage can cause a large change in current. If the applied voltage exceeds the LED's forwa... |
57313fb0497a881900248ce5 | What is a constant-voltage source? | batteries | [
"Light-emitting_diode\n\nThe current–voltage characteristic of an LED is similar to other diodes, in that the current is dependent exponentially on the voltage (see Shockley diode equation). This means that a small change in voltage can cause a large change in current. If the applied voltage exceeds the LED's forwa... |
5731405b497a881900248cf5 | How are most LEDs classified? | Class 1 LED product | [
"Light-emitting_diode\n\nThe vast majority of devices containing LEDs are \"safe under all conditions of normal use\", and so are classified as \"Class 1 LED product\"/\"LED Klasse 1\". At present, only a few LEDs—extremely bright LEDs that also have a tightly focused viewing angle of 8° or less—could, in theory, c... |
5731405b497a881900248cf6 | What does being a Class 1 LED product mean? | safe under all conditions of normal use | [
"Light-emitting_diode\n\nThe vast majority of devices containing LEDs are \"safe under all conditions of normal use\", and so are classified as \"Class 1 LED product\"/\"LED Klasse 1\". At present, only a few LEDs—extremely bright LEDs that also have a tightly focused viewing angle of 8° or less—could, in theory, c... |
5731405b497a881900248cf7 | What type of LED can possibly cause blindness? | extremely bright LEDs | [
"Light-emitting_diode\n\nThe vast majority of devices containing LEDs are \"safe under all conditions of normal use\", and so are classified as \"Class 1 LED product\"/\"LED Klasse 1\". At present, only a few LEDs—extremely bright LEDs that also have a tightly focused viewing angle of 8° or less—could, in theory, c... |
5731405b497a881900248cf8 | What class are extremely bright LEDs listed as? | Class 2 | [
"Light-emitting_diode\n\nThe vast majority of devices containing LEDs are \"safe under all conditions of normal use\", and so are classified as \"Class 1 LED product\"/\"LED Klasse 1\". At present, only a few LEDs—extremely bright LEDs that also have a tightly focused viewing angle of 8° or less—could, in theory, c... |
5731405b497a881900248cf9 | Which government advocated the banning of Class 2 LEDs? | French | [
"Light-emitting_diode\n\nThe vast majority of devices containing LEDs are \"safe under all conditions of normal use\", and so are classified as \"Class 1 LED product\"/\"LED Klasse 1\". At present, only a few LEDs—extremely bright LEDs that also have a tightly focused viewing angle of 8° or less—could, in theory, c... |
57314138497a881900248cff | What substance does fluorescent lamps contain? | mercury | [
"Light-emitting_diode\n\nWhile LEDs have the advantage over fluorescent lamps that they do not contain mercury, they may contain other hazardous metals such as lead and arsenic. Regarding the toxicity of LEDs when treated as waste, a study published in 2011 stated: \"According to federal standards, LEDs are not haz... |
57314138497a881900248d00 | What dangerous metal can LEDs contain? | arsenic | [
"Light-emitting_diode\n\nWhile LEDs have the advantage over fluorescent lamps that they do not contain mercury, they may contain other hazardous metals such as lead and arsenic. Regarding the toxicity of LEDs when treated as waste, a study published in 2011 stated: \"According to federal standards, LEDs are not haz... |
57314138497a881900248d01 | Which LEDs are considered dangerous by a 2011 study? | low-intensity red | [
"Light-emitting_diode\n\nWhile LEDs have the advantage over fluorescent lamps that they do not contain mercury, they may contain other hazardous metals such as lead and arsenic. Regarding the toxicity of LEDs when treated as waste, a study published in 2011 stated: \"According to federal standards, LEDs are not haz... |
57314138497a881900248d02 | According to a California study, what harmful metal is in most LEDs? | lead | [
"Light-emitting_diode\n\nWhile LEDs have the advantage over fluorescent lamps that they do not contain mercury, they may contain other hazardous metals such as lead and arsenic. Regarding the toxicity of LEDs when treated as waste, a study published in 2011 stated: \"According to federal standards, LEDs are not haz... |
57314138497a881900248d03 | What LEDs are considered safer than any other? | low-intensity yellow LEDs | [
"Light-emitting_diode\n\nWhile LEDs have the advantage over fluorescent lamps that they do not contain mercury, they may contain other hazardous metals such as lead and arsenic. Regarding the toxicity of LEDs when treated as waste, a study published in 2011 stated: \"According to federal standards, LEDs are not haz... |
573143ba497a881900248d23 | What type of light is ideal for traffic signals? | One-color light | [
"Light-emitting_diode\n\nOne-color light is well suited for traffic lights and signals, exit signs, emergency vehicle lighting, ships' navigation lights or lanterns (chromacity and luminance standards being set under the Convention on the International Regulations for Preventing Collisions at Sea 1972, Annex I and ... |
573143ba497a881900248d24 | In what year were luminescence standards set? | 1972 | [
"Light-emitting_diode\n\nOne-color light is well suited for traffic lights and signals, exit signs, emergency vehicle lighting, ships' navigation lights or lanterns (chromacity and luminance standards being set under the Convention on the International Regulations for Preventing Collisions at Sea 1972, Annex I and ... |
573143ba497a881900248d25 | What color LEDs are used when night vision is important? | Red or yellow | [
"Light-emitting_diode\n\nOne-color light is well suited for traffic lights and signals, exit signs, emergency vehicle lighting, ships' navigation lights or lanterns (chromacity and luminance standards being set under the Convention on the International Regulations for Preventing Collisions at Sea 1972, Annex I and ... |
573143ba497a881900248d26 | What is an example of a night vision needed area? | astronomy observatories | [
"Light-emitting_diode\n\nOne-color light is well suited for traffic lights and signals, exit signs, emergency vehicle lighting, ships' navigation lights or lanterns (chromacity and luminance standards being set under the Convention on the International Regulations for Preventing Collisions at Sea 1972, Annex I and ... |
573143ba497a881900248d27 | What is another use for one-color light? | exit signs | [
"Light-emitting_diode\n\nOne-color light is well suited for traffic lights and signals, exit signs, emergency vehicle lighting, ships' navigation lights or lanterns (chromacity and luminance standards being set under the Convention on the International Regulations for Preventing Collisions at Sea 1972, Annex I and ... |
5731449ea5e9cc1400cdbdef | Why are LED lights sought after for various applications? | their long life | [
"Light-emitting_diode\n\nBecause of their long life, fast switching times, and their ability to be seen in broad daylight due to their high output and focus, LEDs have been used in brake lights for cars' high-mounted brake lights, trucks, and buses, and in turn signals for some time, but many vehicles now use LEDs ... |
5731449ea5e9cc1400cdbdf0 | Because of their high output, LED lights are very useful where? | brake lights for cars | [
"Light-emitting_diode\n\nBecause of their long life, fast switching times, and their ability to be seen in broad daylight due to their high output and focus, LEDs have been used in brake lights for cars' high-mounted brake lights, trucks, and buses, and in turn signals for some time, but many vehicles now use LEDs ... |
5731449ea5e9cc1400cdbdf1 | LED brake lights are how many times faster than incandescent ones? | 0.5 second | [
"Light-emitting_diode\n\nBecause of their long life, fast switching times, and their ability to be seen in broad daylight due to their high output and focus, LEDs have been used in brake lights for cars' high-mounted brake lights, trucks, and buses, and in turn signals for some time, but many vehicles now use LEDs ... |
5731449ea5e9cc1400cdbdf2 | What color LEDs are now starting to be used more? | White | [
"Light-emitting_diode\n\nBecause of their long life, fast switching times, and their ability to be seen in broad daylight due to their high output and focus, LEDs have been used in brake lights for cars' high-mounted brake lights, trucks, and buses, and in turn signals for some time, but many vehicles now use LEDs ... |
5731449ea5e9cc1400cdbdf3 | What types of light can LEDs form better than incandescent? | thinner | [
"Light-emitting_diode\n\nBecause of their long life, fast switching times, and their ability to be seen in broad daylight due to their high output and focus, LEDs have been used in brake lights for cars' high-mounted brake lights, trucks, and buses, and in turn signals for some time, but many vehicles now use LEDs ... |
5731458d05b4da19006bcf98 | Where are infrared LEDs used in everday life? | theaters | [
"Light-emitting_diode\n\nAssistive listening devices in many theaters and similar spaces use arrays of infrared LEDs to send sound to listeners' receivers. Light-emitting diodes (as well as semiconductor lasers) are used to send data over many types of fiber optic cable, from digital audio over TOSLINK cables to th... |
5731458d05b4da19006bcf99 | How are LEDs used in theaters? | to send sound to listeners' receivers | [
"Light-emitting_diode\n\nAssistive listening devices in many theaters and similar spaces use arrays of infrared LEDs to send sound to listeners' receivers. Light-emitting diodes (as well as semiconductor lasers) are used to send data over many types of fiber optic cable, from digital audio over TOSLINK cables to th... |
5731458d05b4da19006bcf9a | LEDs can send data over what type of cable? | fiber optic | [
"Light-emitting_diode\n\nAssistive listening devices in many theaters and similar spaces use arrays of infrared LEDs to send sound to listeners' receivers. Light-emitting diodes (as well as semiconductor lasers) are used to send data over many types of fiber optic cable, from digital audio over TOSLINK cables to th... |
5731458d05b4da19006bcf9b | What type of fiber forms the backbone of the internet? | very high bandwidth | [
"Light-emitting_diode\n\nAssistive listening devices in many theaters and similar spaces use arrays of infrared LEDs to send sound to listeners' receivers. Light-emitting diodes (as well as semiconductor lasers) are used to send data over many types of fiber optic cable, from digital audio over TOSLINK cables to th... |
573146e3e6313a140071cdaa | In what country does one kilowatt-hour of electricity causes 1.34 pounds of CO 2 emission? | US | [
"Light-emitting_diode\n\nIn the US, one kilowatt-hour (3.6 MJ) of electricity currently causes an average 1.34 pounds (610 g) of CO\n2 emission. Assuming the average light bulb is on for 10 hours a day, a 40-watt bulb will cause 196 pounds (89 kg) of CO\n2 emission per year. The 6-watt LED equivalent will only caus... |
573146e3e6313a140071cdab | How much CO2 emission would a 40-watt light bulb produce after 10 hours? | 196 pounds | [
"Light-emitting_diode\n\nIn the US, one kilowatt-hour (3.6 MJ) of electricity currently causes an average 1.34 pounds (610 g) of CO\n2 emission. Assuming the average light bulb is on for 10 hours a day, a 40-watt bulb will cause 196 pounds (89 kg) of CO\n2 emission per year. The 6-watt LED equivalent will only caus... |
573146e3e6313a140071cdac | A 6-watt LED left on for 10 hours a day will emit how much CO 2? | 30 pounds | [
"Light-emitting_diode\n\nIn the US, one kilowatt-hour (3.6 MJ) of electricity currently causes an average 1.34 pounds (610 g) of CO\n2 emission. Assuming the average light bulb is on for 10 hours a day, a 40-watt bulb will cause 196 pounds (89 kg) of CO\n2 emission per year. The 6-watt LED equivalent will only caus... |
573146e3e6313a140071cdad | How much can a building's carbon footprint be reduced by switching to LEDs? | 85% | [
"Light-emitting_diode\n\nIn the US, one kilowatt-hour (3.6 MJ) of electricity currently causes an average 1.34 pounds (610 g) of CO\n2 emission. Assuming the average light bulb is on for 10 hours a day, a 40-watt bulb will cause 196 pounds (89 kg) of CO\n2 emission per year. The 6-watt LED equivalent will only caus... |
573147db05b4da19006bcfb2 | LEDs are often used for what type of systems? | Machine vision | [
"Light-emitting_diode\n\nMachine vision systems often require bright and homogeneous illumination, so features of interest are easier to process. LEDs are often used for this purpose, and this is likely to remain one of their major uses until the price drops low enough to make signaling and illumination uses more w... |
573147db05b4da19006bcfb3 | Why are LEDs preferred for machine vision systems? | so features of interest are easier to process | [
"Light-emitting_diode\n\nMachine vision systems often require bright and homogeneous illumination, so features of interest are easier to process. LEDs are often used for this purpose, and this is likely to remain one of their major uses until the price drops low enough to make signaling and illumination uses more w... |
573147db05b4da19006bcfb4 | What can help make LEDs more widely used? | price drops | [
"Light-emitting_diode\n\nMachine vision systems often require bright and homogeneous illumination, so features of interest are easier to process. LEDs are often used for this purpose, and this is likely to remain one of their major uses until the price drops low enough to make signaling and illumination uses more w... |
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