> Quick answer: Total harmonic distortion (THD) introduced by LED drivers in solar lamps is not quantified in the provided sources [3]. While switch-mode drivers can introduce harmonic distortion, specific THD values and their practical impact on other electronics are unclear [20].
While total harmonic distortion (THD) is a crucial metric for assessing power quality in electrical systems, its specifics in solar lamp LED drivers remain elusive. This article delves into the nature of THD, how it manifests in switch-mode power supplies (SMPS), and its potential impacts on other electronics.
What Is Total Harmonic Distortion?
Total harmonic distortion (THD) is a measure of harmonics present in non-sinusoidal AC voltage or current waveforms [3]. In the context of solar lamp LED drivers, THD arises due to the nonlinear nature of switch-mode power supplies (SMPS), which are commonly used. SMPS draw current in short pulses rather than smooth sinusoidal waves, leading to harmonic content [20].
Impact on Electrical Systems
LED drivers operating as SMPS can introduce harmonic distortion and poor power factor into AC lines [20]. This is regulated by standards such as EN61000-3-2, which mandates power factor correction (PFC) for switch-mode power supplies to manage harmonic distortion [20]. However, the sources do not specify whether typical solar lamp drivers meet these standards or provide actual THD values.
Potential Interference with Other Electronics
Harmonic distortion and poor power factor can affect electrical systems, particularly in commercial settings. For instance, poor power factor caused by nonlinear loads like conventional LED drivers can lead to additional surcharges for commercial users [20]. This suggests that such drivers can influence the broader electrical environment by introducing reactive power and harmonic distortion, potentially affecting other connected devices or the utility grid.
However, the sources do not specify whether this interference is significant in residential settings or whether it causes measurable issues like equipment malfunction or data corruption. The design of LED drivers in solar lamps is influenced by several factors that indirectly relate to power quality [2].
Design Considerations
Solar LED systems often operate on DC voltages (12V or 24V), which are less prone to harmonic distortion than AC systems [2]. Since solar lamps typically use DC from batteries or solar panels, the AC-to-DC conversion stage may be a primary source of harmonics if present. However, the sources do not clarify whether these drivers include active or passive PFC [20].
Some patents describe advanced driver circuits with features like thermal compensation and voltage identification, which may improve stability but do not address harmonic distortion directly [5][6]. EMI filters are included in some designs to mitigate high-frequency noise, though this is distinct from reducing THD [7].
Dimming and Flicker
Dimming can introduce issues such as flicker or stuttering if dimmers and drivers are mismatched [16][17]. While flicker is a form of temporal light modulation that affects human perception, it is not directly linked to harmonic distortion in the provided sources [23].
Key Takeaways
- THD introduced by LED drivers in solar lamps is not quantified in the available research.
- Switch-mode power supplies (SMPS) used as drivers can introduce harmonic distortion but specific values are unknown.
- Harmonic distortion and poor power factor can affect electrical systems, though residential impact remains unclear.
Frequently Asked Questions
„`json
[
{
„q”: „Do solar lamp LED drivers meet EN61000-3-2 standards?”,
„a”: „The sources do not specify whether typical solar lamp drivers meet the EN61000-3-2 standards for power factor correction (PFC). [20]„
},
{
„q”: „How does harmonic distortion affect residential settings?”,
„a”: „While commercial settings experience additional surcharges due to poor power factor, the impact on residential settings is not quantified in the sources. [20]„
},
{
„q”: „What features do advanced solar lamp drivers have?”,
„a”: „Advanced driver circuits can include thermal compensation and voltage identification, which improve stability but do not address harmonic distortion directly. [5][6]„
}
]
„`
References
- [2] CN107809825A_-_Photovoltaic_controller_and_brightness__b6791ba7 — patent
source passage
LED has many-side in the factor that the application of solar lighting field is restricted：First, the sun Can light fixture rainy days when because generated energy is few, the problem of not working often occurs in light fixture or lighting time is short；2nd, electricity is adapted to Narrow range is pressed, in solar energy lamp system, nominal voltage is generally two kinds of DC12V and DC24V, solar LED control on the market Device processed is mostly directed to a kind of voltage therein, voltage adaptation narrow range；3rd, LED light source power is unadjustable, due to circuit design Problem, many drivers do not possess dimming function, cause LED light source to always work in full power state；4th, defencive function Difference, driver do not possess the functions such as reversal connection, output short-circuit, overvoltage protection, and poor reliability during use, circuit is easy to damage；5th, High temperature has a strong impact on to LED light source service life, when great power LED works under rated current state, can produce heat, LED If junction temperature can not control in safe range, it will accelerate its light decay, shorten LED service life. At present, in order to reduce the operating temperature of LED light source, the fado that does conventional at present is using reduction LED drive circuit Operating current, its shortcoming are that power supply power supplying efficiency is low, can not give full play to LED light source efficiently, the ch
- [3] Power_Management_Chapter_24_Test_and_Measurement__896d0617 — magazine
source passage
fundamental frequency (Fourier Analysis). Total Harmonic Distortion (THD) is a figure of merit that quantifies the level of harmonics in non-sinusoidal ac voltage or current waveforms. System: AC and DC Power Analyzers Power analyzers accurately measure electrical power characteristics of devices that generate, convert, or consume electricity. There are now two types of power analyzers: ac and dc. A dc power analyzer allows engineers to gather and configure multiple instruments to complete dc sourcing and measurement tasks. AC power analyzers provide precise measurements of true power (watts), power factor, harmonics and efficiency in power-conversion equipment. Reliable ac power analyzers enable engineers to minimize energy loss due to distorted, transient waveforms in power electronics such as inverters, motors, lighting circuits, and power supplies. Engineers working on electronic power-conversion systems need high-accuracy measurements to identify and characterize incremental efficiency improvements. Precision ac power analyzers offer high accuracy and ease of connection to the DUT, making them ideal for steady-state measurements of power consumption, efficiency, and power quality. For these measurements, the accuracy of the power analyzer gives R&D engineers the measurement integrity they need. With floating inputs and directly connected measurements, precision power analyzers make it easy for engineers to connect to their DUTs. Traditionally, only oscilloscopes offer th
- [5] CN101626652A_-_Dimmable_LED_constant_current_source_driver_with__acd3cd20 — patent
source passage
driver in the illuminating field. The driver comprises a voltage identification circuit, a light compensation circuit, an MCU control circuit, a temperature compensation circuit and a dimmable constant current source circuit, wherein the output ends of the voltage identification circuit, the light compensation circuit and the temperature compensation circuit are all connected with the input end of the MCU control circuit, the PWM output end of the MCU control circuit is connected with the input end of the dimmable constant current source circuit, the voltage identification circuit and the dimmable constant current source circuit are both connected into direct-current or alternating-current input voltage, the light compensation circuit is connected with a photosensitive device, the temperature compensation circuit is connected with a thermistor, and the output end of the dimmable constant current source circuit is connected with an LED light source. The invention has low cost, small volume, stable and reliable working of a system and prolongs the service life of an LED. Description Technical field The present invention relates to a kind of led light source driver in the lighting field, relate in particular to a kind of Dimmable LED constant current source driver with wide voltage range. Background technology Current, in short supply and national the vigorously advocating under the energy-saving and cost-reducing background in global energy, along with science and technology de
- [6] CA2829235C_-_Boost_converter_of_driver_circuit_with_thermal__d33400ad — patent
source passage
ADAPTATION AGAINST CLIMATE CHANGE – Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS – Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps – Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED] Landscapes – Circuit Arrangement For Electric Light Sources In General (AREA) – Dc-Dc Converters (AREA) – Led Devices (AREA) Abstract A circuit for providing thermal compensation for a driver circuit used to drive light emitting diodes (LEDs) is provided. The driver circuit can include a rectifier circuit configured to rectify an AC power source into a DC power source providing a DC source voltage. The driver circuit can further include a boost circuit configured to boost the DC source voltage to provide a drive voltage for driving the light emitting diodes. The boost circuit can include a switching element that is controlled based at least in part on a current sense circuit having a sense transistor. A thermal tracking transistor is provided as part of the reference to the sense circuit. Description 261877 = BOOST CONVERTER OF DRIVER CIRCUIT WITH THERMAL COMPENSATION FIELD OF THE INVENTION [0001] The present disclosure relates to a driver circuit for driving light emitting diodes (LEDs), and more particularly to providing thermal compensation for a driver circuit for driving LEDs. BACKGROUND OF THE INVENTION B
- [7] US9992826B1_-_Dual_mode_constant_current_LED_driver__71bc120a — patent
source passage
the output voltage of the driver using a DC voltage signal provided by the DC power source, a current flowing through the first inductor, a switching frequency of the first switch, and a duty ratio of the first switch. – the device may further include an electro-magnetic interference (EMI) filter operatively connected between the DC power source and the converter, and configured to eliminate high frequency components of a DC voltage signal from the DC power source. – EMI electro-magnetic interference Landscapes – Circuit Arrangement For Electric Light Sources In General (AREA) Abstract A dual mode constant output current LED driver is capable of operating with a very wide range of input direct current (DC) voltage. This provides an effective topology for a wide range of constant output current LED drivers, and allows for changing the number of connected LEDs without negatively impacting the output current. The LED driver includes a converter and a mode selection circuit that control the modes of the circuit based on the voltage. The converter and mode selection circuit operate in a buck-boost mode when the output voltage of the LED driver is less than the DC input voltage plus a first threshold amount, and in a boost mode when the output voltage of the LED driver is greater than the DC input voltage plus a second threshold amount. Description The present disclosure relates to power supplies suitable for driving light emitting diode (LED) lighting systems as well as other elec
- [16] 10_things_you_must_know_before_you_dim_led_lamps_-_Lux_Review_-_your__7d64683c — magazine
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# 10 things you must know before you dim led lamps – Lux Review – your independent guide to lighting Source: Blog/Web URL: https://www.luxreview.com/article/2016/02/10-things-you-must-know-before-you-dim-led-lamps Author: John Bullock Date: 2016-02-10 Some months ago, Lux Review opened this discussion with Dimming LED lamps: the dos and don’ts. Here we delve further into the issue and look at what it means once the decision’s taken to go ahead with a dimmable LED installation. Here are a few things that you need to avoid: – Flicker – Flashing – Stuttering dimming – Insufficient dimming – Failed LED driver – Failed dimmer These are all inconveniences that are await you should you mismatch the electronics of the LED driver and the dimmer. Choose the dimming method first There are thousands of different dimmable LED light fixtures on the market, but only three major types of dimming method: mains dimming, Dali or DMX. (see box, below) So choose what kind of dimming you want before you select any LED luminaires. More lighting control manufacturers are providing lists of LED products that they have tested for compatibility with their equipment and this is a very useful service to any specifier. Don’t buy cheap drivers Most lighting control systems offer a variety of dimming protocols, the languages which they use to communicate with the lamp or driver. When you’ve chosen the method that’s right for your installation, you need to get LED drivers which match the performance and the
- [17] 10_things_you_must_know_before_you_dim_led_lamps_-_Lux_Review_-_your__7d64683c — authority
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# 10 things you must know before you dim led lamps – Lux Review – your independent guide to lighting Source: Blog/Web URL: https://www.luxreview.com/article/2016/02/10-things-you-must-know-before-you-dim-led-lamps Author: John Bullock Date: 2016-02-10 Some months ago, Lux Review opened this discussion with Dimming LED lamps: the dos and don’ts. Here we delve further into the issue and look at what it means once the decision’s taken to go ahead with a dimmable LED installation. Here are a few things that you need to avoid: – Flicker – Flashing – Stuttering dimming – Insufficient dimming – Failed LED driver – Failed dimmer These are all inconveniences that are await you should you mismatch the electronics of the LED driver and the dimmer. Choose the dimming method first There are thousands of different dimmable LED light fixtures on the market, but only three major types of dimming method: mains dimming, Dali or DMX. (see box, below) So choose what kind of dimming you want before you select any LED luminaires. More lighting control manufacturers are providing lists of LED products that they have tested for compatibility with their equipment and this is a very useful service to any specifier. Don’t buy cheap drivers Most lighting control systems offer a variety of dimming protocols, the languages which they use to communicate with the lamp or driver. When you’ve chosen the method that’s right for your installation, you need to get LED drivers which match the performance and the
- [20] US9854640B2_-_Solid-state_lighting_control_with_-_Google_Patents__0688f058 — patent
source passage
such dimmers typically cut voltage phase over the current peak as required by the load, causing imbalance and harmonic distortion on the AC line. Poor power factor is rarely noticed by residential end-users because their utility companies usually pay the price by spending money on hardware and additional power to correct for this imbalance throughout their distribution systems. However, commercial users may either pay additional surcharges for low power factor or improve it at their own cost. For example, if their loads are highly inductive, they may have to install capacitor switch banks to compensate for this power loss. A conventional driver employed to drive an LED-based lamp basically uses a switch-mode power supply (SMPS) and is considered to be nonlinear with reactive loads, which requires power factor correction (PFC) to reduce non-sinusoidal current distortion and excess energy at harmonics of the line frequency of the voltage. The EU standard EN61000-3-2 regulates harmonic contents and basic PFC criteria for all such switch-mode power supplies. Passive PFC in drivers/power supplies adopted in LED-based lamps usually involve adding capacitors, resistors and steering diodes in a valley-fill circuit. However, the power factor improvement using such a passive PFC circuit is limited. Active PFC involves redistributing the current over the voltage half-cycle waveform. The key is how to improve load regulation without adversely affecting the power factor or to make the loa
- [23] Light-Emitting_Diodes_LEDs_-_Berkeley_Lab_EHS__86f5e17f — authority
source passage
full-spectrum optical radiation from sunlight. Bright light sources such as the sun, arc lamps, welding arcs, and bright LEDs produce a natural aversion response by the eye. This response limits the duration of exposure to a fraction of a second (typically less than 0.25 s). Visual Disturbance and Circadian Rhythm Disruption The only established acute adverse health effects from LEDs are those caused by temporal light modulation (flicker), glare, and circadian rhythm disruption. Flicker effects Light sources driven directly from the main power supply are likely to have a degree of temporal light modulation. Most A/C-driven LEDs are subject to flicker effects, regardless of the emission spectrum. Glare Glare is a source of indirect hazards, which are not caused by the light itself. For example, in the workplace, glare can cause accidents when it interferes with the safe use of machines and tools. In everyday life, glare can be the cause of vehicular accidents and falls. Glare can also create visual disturbances when LED light fixtures are not properly designed. – Discomfort glare is produced when a light source has a luminance (brightness) vastly greater than surrounding objects (e.g., an auto headlight on a very dark country road is brighter than the same light viewed in daylight). People complain of discomfort under these types of conditions. – Disability glare is produced when the luminance of the source is so bright that the scattering of light within the human eye obscure
LED has many-side in the factor that the application of solar lighting field is restricted：First, the sun Can light fixture rainy days when because generated energy is few, the problem of not working often occurs in light fixture or lighting time is short；2nd, electricity is adapted to Narrow range is pressed, in solar energy lamp system, nominal voltage is generally two kinds of DC12V and DC24V, solar LED control on the market Device processed is mostly directed to a kind of voltage therein, voltage adaptation narrow range；3rd, LED light source power is unadjustable, due to circuit design Problem, many drivers do not possess dimming function, cause LED light source to always work in full power state；4th, defencive function Difference, driver do not possess the functions such as reversal connection, output short-circuit, overvoltage protection, and poor reliability during use, circuit is easy to damage；5th, High temperature has a strong impact on to LED light source service life, when great power LED works under rated current state, can produce heat, LED If junction temperature can not control in safe range, it will accelerate its light decay, shorten LED service life. At present, in order to reduce the operating temperature of LED light source, the fado that does conventional at present is using reduction LED drive circuit Operating current, its shortcoming are that power supply power supplying efficiency is low, can not give full play to LED light source efficiently, the ch
fundamental frequency (Fourier Analysis). Total Harmonic Distortion (THD) is a figure of merit that quantifies the level of harmonics in non-sinusoidal ac voltage or current waveforms. System: AC and DC Power Analyzers Power analyzers accurately measure electrical power characteristics of devices that generate, convert, or consume electricity. There are now two types of power analyzers: ac and dc. A dc power analyzer allows engineers to gather and configure multiple instruments to complete dc sourcing and measurement tasks. AC power analyzers provide precise measurements of true power (watts), power factor, harmonics and efficiency in power-conversion equipment. Reliable ac power analyzers enable engineers to minimize energy loss due to distorted, transient waveforms in power electronics such as inverters, motors, lighting circuits, and power supplies. Engineers working on electronic power-conversion systems need high-accuracy measurements to identify and characterize incremental efficiency improvements. Precision ac power analyzers offer high accuracy and ease of connection to the DUT, making them ideal for steady-state measurements of power consumption, efficiency, and power quality. For these measurements, the accuracy of the power analyzer gives R&D engineers the measurement integrity they need. With floating inputs and directly connected measurements, precision power analyzers make it easy for engineers to connect to their DUTs. Traditionally, only oscilloscopes offer th
driver in the illuminating field. The driver comprises a voltage identification circuit, a light compensation circuit, an MCU control circuit, a temperature compensation circuit and a dimmable constant current source circuit, wherein the output ends of the voltage identification circuit, the light compensation circuit and the temperature compensation circuit are all connected with the input end of the MCU control circuit, the PWM output end of the MCU control circuit is connected with the input end of the dimmable constant current source circuit, the voltage identification circuit and the dimmable constant current source circuit are both connected into direct-current or alternating-current input voltage, the light compensation circuit is connected with a photosensitive device, the temperature compensation circuit is connected with a thermistor, and the output end of the dimmable constant current source circuit is connected with an LED light source. The invention has low cost, small volume, stable and reliable working of a system and prolongs the service life of an LED. Description Technical field The present invention relates to a kind of led light source driver in the lighting field, relate in particular to a kind of Dimmable LED constant current source driver with wide voltage range. Background technology Current, in short supply and national the vigorously advocating under the energy-saving and cost-reducing background in global energy, along with science and technology de
ADAPTATION AGAINST CLIMATE CHANGE – Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS – Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps – Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED] Landscapes – Circuit Arrangement For Electric Light Sources In General (AREA) – Dc-Dc Converters (AREA) – Led Devices (AREA) Abstract A circuit for providing thermal compensation for a driver circuit used to drive light emitting diodes (LEDs) is provided. The driver circuit can include a rectifier circuit configured to rectify an AC power source into a DC power source providing a DC source voltage. The driver circuit can further include a boost circuit configured to boost the DC source voltage to provide a drive voltage for driving the light emitting diodes. The boost circuit can include a switching element that is controlled based at least in part on a current sense circuit having a sense transistor. A thermal tracking transistor is provided as part of the reference to the sense circuit. Description 261877 = BOOST CONVERTER OF DRIVER CIRCUIT WITH THERMAL COMPENSATION FIELD OF THE INVENTION [0001] The present disclosure relates to a driver circuit for driving light emitting diodes (LEDs), and more particularly to providing thermal compensation for a driver circuit for driving LEDs. BACKGROUND OF THE INVENTION B
the output voltage of the driver using a DC voltage signal provided by the DC power source, a current flowing through the first inductor, a switching frequency of the first switch, and a duty ratio of the first switch. – the device may further include an electro-magnetic interference (EMI) filter operatively connected between the DC power source and the converter, and configured to eliminate high frequency components of a DC voltage signal from the DC power source. – EMI electro-magnetic interference Landscapes – Circuit Arrangement For Electric Light Sources In General (AREA) Abstract A dual mode constant output current LED driver is capable of operating with a very wide range of input direct current (DC) voltage. This provides an effective topology for a wide range of constant output current LED drivers, and allows for changing the number of connected LEDs without negatively impacting the output current. The LED driver includes a converter and a mode selection circuit that control the modes of the circuit based on the voltage. The converter and mode selection circuit operate in a buck-boost mode when the output voltage of the LED driver is less than the DC input voltage plus a first threshold amount, and in a boost mode when the output voltage of the LED driver is greater than the DC input voltage plus a second threshold amount. Description The present disclosure relates to power supplies suitable for driving light emitting diode (LED) lighting systems as well as other elec
# 10 things you must know before you dim led lamps – Lux Review – your independent guide to lighting Source: Blog/Web URL: https://www.luxreview.com/article/2016/02/10-things-you-must-know-before-you-dim-led-lamps Author: John Bullock Date: 2016-02-10 Some months ago, Lux Review opened this discussion with Dimming LED lamps: the dos and don’ts. Here we delve further into the issue and look at what it means once the decision’s taken to go ahead with a dimmable LED installation. Here are a few things that you need to avoid: – Flicker – Flashing – Stuttering dimming – Insufficient dimming – Failed LED driver – Failed dimmer These are all inconveniences that are await you should you mismatch the electronics of the LED driver and the dimmer. Choose the dimming method first There are thousands of different dimmable LED light fixtures on the market, but only three major types of dimming method: mains dimming, Dali or DMX. (see box, below) So choose what kind of dimming you want before you select any LED luminaires. More lighting control manufacturers are providing lists of LED products that they have tested for compatibility with their equipment and this is a very useful service to any specifier. Don’t buy cheap drivers Most lighting control systems offer a variety of dimming protocols, the languages which they use to communicate with the lamp or driver. When you’ve chosen the method that’s right for your installation, you need to get LED drivers which match the performance and the
# 10 things you must know before you dim led lamps – Lux Review – your independent guide to lighting Source: Blog/Web URL: https://www.luxreview.com/article/2016/02/10-things-you-must-know-before-you-dim-led-lamps Author: John Bullock Date: 2016-02-10 Some months ago, Lux Review opened this discussion with Dimming LED lamps: the dos and don’ts. Here we delve further into the issue and look at what it means once the decision’s taken to go ahead with a dimmable LED installation. Here are a few things that you need to avoid: – Flicker – Flashing – Stuttering dimming – Insufficient dimming – Failed LED driver – Failed dimmer These are all inconveniences that are await you should you mismatch the electronics of the LED driver and the dimmer. Choose the dimming method first There are thousands of different dimmable LED light fixtures on the market, but only three major types of dimming method: mains dimming, Dali or DMX. (see box, below) So choose what kind of dimming you want before you select any LED luminaires. More lighting control manufacturers are providing lists of LED products that they have tested for compatibility with their equipment and this is a very useful service to any specifier. Don’t buy cheap drivers Most lighting control systems offer a variety of dimming protocols, the languages which they use to communicate with the lamp or driver. When you’ve chosen the method that’s right for your installation, you need to get LED drivers which match the performance and the
such dimmers typically cut voltage phase over the current peak as required by the load, causing imbalance and harmonic distortion on the AC line. Poor power factor is rarely noticed by residential end-users because their utility companies usually pay the price by spending money on hardware and additional power to correct for this imbalance throughout their distribution systems. However, commercial users may either pay additional surcharges for low power factor or improve it at their own cost. For example, if their loads are highly inductive, they may have to install capacitor switch banks to compensate for this power loss. A conventional driver employed to drive an LED-based lamp basically uses a switch-mode power supply (SMPS) and is considered to be nonlinear with reactive loads, which requires power factor correction (PFC) to reduce non-sinusoidal current distortion and excess energy at harmonics of the line frequency of the voltage. The EU standard EN61000-3-2 regulates harmonic contents and basic PFC criteria for all such switch-mode power supplies. Passive PFC in drivers/power supplies adopted in LED-based lamps usually involve adding capacitors, resistors and steering diodes in a valley-fill circuit. However, the power factor improvement using such a passive PFC circuit is limited. Active PFC involves redistributing the current over the voltage half-cycle waveform. The key is how to improve load regulation without adversely affecting the power factor or to make the loa
full-spectrum optical radiation from sunlight. Bright light sources such as the sun, arc lamps, welding arcs, and bright LEDs produce a natural aversion response by the eye. This response limits the duration of exposure to a fraction of a second (typically less than 0.25 s). Visual Disturbance and Circadian Rhythm Disruption The only established acute adverse health effects from LEDs are those caused by temporal light modulation (flicker), glare, and circadian rhythm disruption. Flicker effects Light sources driven directly from the main power supply are likely to have a degree of temporal light modulation. Most A/C-driven LEDs are subject to flicker effects, regardless of the emission spectrum. Glare Glare is a source of indirect hazards, which are not caused by the light itself. For example, in the workplace, glare can cause accidents when it interferes with the safe use of machines and tools. In everyday life, glare can be the cause of vehicular accidents and falls. Glare can also create visual disturbances when LED light fixtures are not properly designed. – Discomfort glare is produced when a light source has a luminance (brightness) vastly greater than surrounding objects (e.g., an auto headlight on a very dark country road is brighter than the same light viewed in daylight). People complain of discomfort under these types of conditions. – Disability glare is produced when the luminance of the source is so bright that the scattering of light within the human eye obscure