In general, LED can be used for more than 50000 hours, and some manufacturers are promoting their LED to operate for about 100000 hours. The main problem in this area is that LED is not simply no longer operational. Its rated service life can not be calculated by traditional lamps and lanterns. In fact, when testing the life of LED, no one will be waiting for it to stop functioning. However, there are other ways to measure the life of LED. The reason why LED is durable is that it does not produce filament fuses. LED will not stop operation directly, but it will gradually deteriorate over time. It is predicted that high quality LED can maintain more than 60% of the initial lamp brightness after 50000 hours of continuous operation. Assuming that LED has reached its rated service life, it may still be luminous, but the light is very weak.
Without considering the power and driving failures, the life span of LED is characterized by its decay, that is, the longer the time is, the more darker the brightness will be, until finally extinguished. The time of decay of 30% is usually defined as its life. So can the life of LED be predicted?
1. Light failure of LED
Most white LED is obtained by irradiating yellow phosphor with blue LED. There are two main reasons for LED fading. One is the decay of Blu ray LED itself, and the blue light LED has far more light decay than red light, yellow light and green light LED. Another is the decay of phosphor, and the attenuation of phosphor at high temperature is very serious.
The decay of LED is related to its junction temperature. The so-called junction temperature is the temperature of the semiconductor pn junction. The higher the junction temperature is, the earlier the decay occurs, that is, the shorter the life. If the junction temperature is 105 degrees, the lifetime of the brightness to 70% is only more than 10000 hours, 95 degrees will be 20 thousand hours, and the junction temperature is reduced to 75 degrees, the life will be 50 thousand hours, and 65 degrees can be extended to 90 thousand hours. So the key to prolonging life is to reduce junction temperature. But these data are only suitable for Cree’s LED. It’s not suitable for other companies’ LED. When the junction temperature is increased from 115 to 135, the life will be reduced from 50000 hours to 20000 hours.
2. How can we prolong the life of LED?
The key to prolonging its life is to reduce its junction temperature. The key to lowering the junction temperature is to have good radiator. It is able to send out the heat generated by LED in time.
3. How to predict the life of this lamp.
Judging from the junction temperature, life expectancy should be very simple. You can know that the life of LED can reach 20 thousand hours at the temperature of 95 knots. However, this method for indoor LED lamps and lanterns has certain credibility, if applied to outdoor LED lamps, especially high power LED street lamps, there are many uncertainties. The biggest problem is that the heat dissipation efficiency of the LED Street radiators decreases with time. This is due to the accumulation of dust and bird droppings, resulting in reduced heat dissipation efficiency. Also because there is a strong ultraviolet light outside, it will also reduce the life of LED. Ultraviolet radiation plays an important role in the aging of encapsulated epoxy resin. If silica gel is used, it can be improved. Ultraviolet radiation also has some bad effects on the aging of phosphors, but it is not very serious.
The LEDLM-80PL LED luminous flux maintenance rate and aging life testing system, launched by Shanghai power Shantou, are designed and manufactured according to the CIE and IEC standards such as IES-LM-80, IES-LM-82, TM-21, GB2312-80 and so on. It can record the curve of luminous flux with time and the curve of color parameter changing with time. The life time of LED is calculated by testing the data of light decay for a short time.
Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.
Our main products are Goniophotometer, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.
Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com, Cell/WhatsApp:+8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp:+8618917996096
Wednesday, June 17, 2020
Equivalent Test Between Normal & High Frequency Fluorescent Lamp and LED Tube
Comparing with traditional fluorescent lamp, the LED tube have high light effects, low power consume, long life time and stable luminous efficiency advantages etc. At the same time, for the LED tube performance testing is became more simple, in recent years more and more customers has chosen the LED tube to replace fluorescent lamp.
Due to the main lighting products are consist of traditional fluorescent lamp, like the CFL and fluorescent lamp are still occupy a large part of market, it’s impossible to replace all of them immediately, specially at the business centre and market still have many fluorescent lamps and compacted lighting products; if replace all fluorescent lamp to LED tube, it’s need lots of tome and huge cost, the most important is this way can’t be approved. In order to make replacement work more effective, the IEC issued the IEC 62776 standard dated December of 2014, this standard explain how to do equivalent test between normal & high frequency fluorescent lamp and LED tube. Before large scale replace fluorescent lamp to LED tube, we have to make sure the LED tube whether can turn on and meet lighting demand, the lighting demand have two points: the first is require the LED tube have lower power consume than fluorescent lamp; the second is based on consume same power, the LED tube have to higher light effects than fluorescent lamp, so we will discuss the comparison test between fluorescent lamp and LED tube. The below is IEC62776 standard and equivalent test explanation:
The IEC 62776 standard from chapter 1 to chapter 3.2 are mentioned the LED tube can replace the double-capped fluorescent and how to use G5 and G13 lamp holder fluorescent lamp turn to LED tube, this kind of equivalent replacement needn’t LED tube to do any change, this standard only talk about G5 and G13 lamp holder of LED tube(1 Scope). At the same time, this standard also mentioned the IEC 60081 double-capped fluorescent lamp performance test and LED tube suitable replace fluorescent lamp with integrated magnetic ballasts. How to do equivalent test between LED tube and fluorescent lamp, there will be use a high frequency power supply and high frequency adjustable reference ballast. As we knew the fluorescent lamp is consist of fluorescent capillary, electrical ballast and fixture, the IEC 60081 and IEC 60901 both standards have clear explanation for how to testing fluorescent capillary. The testing process is connect RB-3 adjustable resistance ballast with double-capped of fluorescent capillary, also we need connect HFP-800 high frequency power supply with double-capped of fluorescent capillary, some of fluorescent capillary need to do preheating process according to IEC standard’s requirement, as below picture. At the same time, the relevant parameters need set up according to IEC standard’s requirement.
Click to learn more details on How to Measure the High Frequency Fluorescent Lamp. For the equivalent test between fluorescent lamp and LED tube, actually, it’s take away the fluorescent capillary and connect LED tube(included driver) with EB, it’s have necessary to explain the working principle of EB and driver: the EB is AC to AC model, when turn on the fluorescent lamp, there have a AC model high voltage to electric shock fluorescent capillary for lighting lamp, then the EB will output constant AC voltage to maintain the fluorescent lamp is always lighting on; the LED driver is AC to DC model, there have a DC power to lighting on singled LED or LED luminaires. So there use a LED tube(included driver) connect with EB which also keep AC to AC model, the equivalent test have three purposes: One is lighting on LED tube; Second is see whether the power consume of LED tube is lower than fluorescent lamp or not; third is light effect of LED tube is higher than fluorescent lamp(this will be judge by spectrometer & integrating sphere system). If need use best fair way to assess these three purpose, the EB is important, we can’t use any of EB to do this kind of equivalent test, this EB must be mentioned or recommend by IEC or other standards, to solve this issue, Shanghai Lisun Electronic office developed HFP-800 High Frequency Power Supply and RB-3 High Frequency Adjustable Reference Ballast, both device are fully meet IEC60081 IEC60901 and ANSI C78.81 & C82.11standards. As we know the reference ballast is special designed for select reference light(fluorescent capillary), the characteristics of reference ballast have constant voltage and current ratio based on rated frequency, and it couldn’t have any affected by voltage, temperature and ambient changes. The RB-3 is application with no sense of resistance ballast, the HFP-800 provide high frequency reference ballast with pure and high frequency power supply. The HFP-800+RB-3 system not only can to do T5/T8 fluorescent lamp test, but also can to do LED tube equivalent test.
Finally, we can see the difference of fluorescent lamp test and LED tube equivalent test. According to standard’s requirement, for the fluorescent lamp test, there must use relevant device, set up preheat current and preheat time to lighting on fluorescent lamp(As picture 1 show). Due to LED tube is special, when to do connection, we needn’t this device(As picture 2 show):
Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.
Our main products are Goniophotometer, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.
Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com, Cell/WhatsApp:+8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp:+8618917996096
Due to the main lighting products are consist of traditional fluorescent lamp, like the CFL and fluorescent lamp are still occupy a large part of market, it’s impossible to replace all of them immediately, specially at the business centre and market still have many fluorescent lamps and compacted lighting products; if replace all fluorescent lamp to LED tube, it’s need lots of tome and huge cost, the most important is this way can’t be approved. In order to make replacement work more effective, the IEC issued the IEC 62776 standard dated December of 2014, this standard explain how to do equivalent test between normal & high frequency fluorescent lamp and LED tube. Before large scale replace fluorescent lamp to LED tube, we have to make sure the LED tube whether can turn on and meet lighting demand, the lighting demand have two points: the first is require the LED tube have lower power consume than fluorescent lamp; the second is based on consume same power, the LED tube have to higher light effects than fluorescent lamp, so we will discuss the comparison test between fluorescent lamp and LED tube. The below is IEC62776 standard and equivalent test explanation:
The IEC 62776 standard from chapter 1 to chapter 3.2 are mentioned the LED tube can replace the double-capped fluorescent and how to use G5 and G13 lamp holder fluorescent lamp turn to LED tube, this kind of equivalent replacement needn’t LED tube to do any change, this standard only talk about G5 and G13 lamp holder of LED tube(1 Scope). At the same time, this standard also mentioned the IEC 60081 double-capped fluorescent lamp performance test and LED tube suitable replace fluorescent lamp with integrated magnetic ballasts. How to do equivalent test between LED tube and fluorescent lamp, there will be use a high frequency power supply and high frequency adjustable reference ballast. As we knew the fluorescent lamp is consist of fluorescent capillary, electrical ballast and fixture, the IEC 60081 and IEC 60901 both standards have clear explanation for how to testing fluorescent capillary. The testing process is connect RB-3 adjustable resistance ballast with double-capped of fluorescent capillary, also we need connect HFP-800 high frequency power supply with double-capped of fluorescent capillary, some of fluorescent capillary need to do preheating process according to IEC standard’s requirement, as below picture. At the same time, the relevant parameters need set up according to IEC standard’s requirement.
Click to learn more details on How to Measure the High Frequency Fluorescent Lamp. For the equivalent test between fluorescent lamp and LED tube, actually, it’s take away the fluorescent capillary and connect LED tube(included driver) with EB, it’s have necessary to explain the working principle of EB and driver: the EB is AC to AC model, when turn on the fluorescent lamp, there have a AC model high voltage to electric shock fluorescent capillary for lighting lamp, then the EB will output constant AC voltage to maintain the fluorescent lamp is always lighting on; the LED driver is AC to DC model, there have a DC power to lighting on singled LED or LED luminaires. So there use a LED tube(included driver) connect with EB which also keep AC to AC model, the equivalent test have three purposes: One is lighting on LED tube; Second is see whether the power consume of LED tube is lower than fluorescent lamp or not; third is light effect of LED tube is higher than fluorescent lamp(this will be judge by spectrometer & integrating sphere system). If need use best fair way to assess these three purpose, the EB is important, we can’t use any of EB to do this kind of equivalent test, this EB must be mentioned or recommend by IEC or other standards, to solve this issue, Shanghai Lisun Electronic office developed HFP-800 High Frequency Power Supply and RB-3 High Frequency Adjustable Reference Ballast, both device are fully meet IEC60081 IEC60901 and ANSI C78.81 & C82.11standards. As we know the reference ballast is special designed for select reference light(fluorescent capillary), the characteristics of reference ballast have constant voltage and current ratio based on rated frequency, and it couldn’t have any affected by voltage, temperature and ambient changes. The RB-3 is application with no sense of resistance ballast, the HFP-800 provide high frequency reference ballast with pure and high frequency power supply. The HFP-800+RB-3 system not only can to do T5/T8 fluorescent lamp test, but also can to do LED tube equivalent test.
Finally, we can see the difference of fluorescent lamp test and LED tube equivalent test. According to standard’s requirement, for the fluorescent lamp test, there must use relevant device, set up preheat current and preheat time to lighting on fluorescent lamp(As picture 1 show). Due to LED tube is special, when to do connection, we needn’t this device(As picture 2 show):
Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.
Our main products are Goniophotometer, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.
Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com, Cell/WhatsApp:+8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp:+8618917996096
Wednesday, June 10, 2020
LED packaging principle
LED package is mainly to provide a platform for LED chips, so that LED chips have better performance of light, electricity and heat. Good packaging can make LEDs have better luminous efficiency and good heat dissipation environment, and good heat dissipation environment can enhance LEDs. The service life. LED packaging technology is mainly built on five main considerations, namely optical extraction efficiency, thermal resistance, power dissipation, reliability and cost performance (Lm/$).
There are many kinds of LED chip packages, and different styles of packages should be used according to the actual photoelectric characteristics. However, the common LED packages have the following five common patterns.
First, the LED chip soft package, this package style is generally used in the LED display of character display, digital display, and electric display. The soft package of the LED chip is to directly bond the LED chip on the PCB printing plate, and connect the desired characters and display effects through the welding wire. These chips and wire bonds are then protected with a transparent resin.
Second, the pin packing method. The main advantage of this kind of package is that it can flexibly control the angle of light emitted by the LED chip, and it can also easily realize the function of measuring light. The pin package method only needs to fix the chip on the lead frame and then encapsulate it with epoxy resin. Can be a single LED device.
Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.
Our main products are Goniophotometer, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.
Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com, Cell/WhatsApp:+8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp:+8618917996096
There are many kinds of LED chip packages, and different styles of packages should be used according to the actual photoelectric characteristics. However, the common LED packages have the following five common patterns.
First, the LED chip soft package, this package style is generally used in the LED display of character display, digital display, and electric display. The soft package of the LED chip is to directly bond the LED chip on the PCB printing plate, and connect the desired characters and display effects through the welding wire. These chips and wire bonds are then protected with a transparent resin.
Second, the pin packing method. The main advantage of this kind of package is that it can flexibly control the angle of light emitted by the LED chip, and it can also easily realize the function of measuring light. The pin package method only needs to fix the chip on the lead frame and then encapsulate it with epoxy resin. Can be a single LED device.
Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.
Our main products are Goniophotometer, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.
Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com, Cell/WhatsApp:+8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp:+8618917996096
How to measure electric, photometric and colorimetric parameters for LED lamps and lanterns?
The main parameters of LED lamps and lanterns include:
A: Electric parameters: voltage, current, lamp power, power factor, harmonic, etc
B: Colorimetric parameters: correlated color temperature, color rendering index, chromaticity tolerance, color coordinates, SDCM, etc
C: Photometric parameters: luminous flux, output luminous efficiency, beam angle, UGR table, intensity distribution, candela table, IES LDT files, etc
(1) Electrical parameters are very easy to measure. Just apply one power meter to the integrating sphere system or goniophotometer system.
(2) There are two methods for colorimetric parameters measurement.
First, we use spectroradiometer integrating sphere system.
Second, we put a spectroradiometer and color sensor in the goniophotometer darkroom. You can measure color property parameters and also color temperature distribution according to the angle.
(3) For total lumen, luminou flux measurement, there are also two methods.
First, we use spectroradiometer integrating sphere system. This method is better for light sources and small lamps.Sencond, we use goniophotometer system. This method is better for big lamps and luminaries.
(4) There are some other photometric parameters, such as beam angle, UGR table, intensity distribution, candela table, IES files. These parameters all have to do with space or angles. The only method is using goniophotometer.
Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.
Our main products are Goniophotometer, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, IP Waterproof Test Equipment, Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.
Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com, Cell/WhatsApp:+8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp:+8618917996096
A: Electric parameters: voltage, current, lamp power, power factor, harmonic, etc
B: Colorimetric parameters: correlated color temperature, color rendering index, chromaticity tolerance, color coordinates, SDCM, etc
C: Photometric parameters: luminous flux, output luminous efficiency, beam angle, UGR table, intensity distribution, candela table, IES LDT files, etc
(1) Electrical parameters are very easy to measure. Just apply one power meter to the integrating sphere system or goniophotometer system.
(2) There are two methods for colorimetric parameters measurement.
First, we use spectroradiometer integrating sphere system.
Second, we put a spectroradiometer and color sensor in the goniophotometer darkroom. You can measure color property parameters and also color temperature distribution according to the angle.
(3) For total lumen, luminou flux measurement, there are also two methods.
First, we use spectroradiometer integrating sphere system. This method is better for light sources and small lamps.Sencond, we use goniophotometer system. This method is better for big lamps and luminaries.
(4) There are some other photometric parameters, such as beam angle, UGR table, intensity distribution, candela table, IES files. These parameters all have to do with space or angles. The only method is using goniophotometer.
Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.
Our main products are Goniophotometer, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, IP Waterproof Test Equipment, Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.
Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com, Cell/WhatsApp:+8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp:+8618917996096
Thursday, June 4, 2020
Characteristics of LISUN GDJS series High and Low Temperature Humidity Chamber
LISUN GDJS series High and Low Temperature Humidity Chamber is according to IEC60068-2-1 (GB/T2423.1) and IEC60068-2-2 (GB/T2423.2). It is used to test the CFL/LED which meets IES LM-80-08, electricity products, electronic components, material and so on.
There is some other manufacturers in China also produce High and Low Temperature Humidity Chamber, and our equipment is mainly different from the following four points:
(1) Display temperature: We use Schneider or Omron’s relay. And the temperature that can be reached is the temperature under load. But many manufacturers refers to the temperature without load. If under load, the temperature must be different from the original temperature.
(2) Water purification device: To generate humidity inside the equipment, there must be distilled water. And there is a water purification device in our High and Low Temperature Humidity Chamber, so we can use tap water directly, to save the cost of distilled water. But many other manufacturers do not have water purification device in the machine.
(3) Temperature sensor: We use electronic temperature sensor, which can use for long time; while other domestic manufacturers use wire ball which is very easy to be bad to save costs.
(4) After-sales service: LISUN has engineers who visit our customers to do after-sales service all over the world, and all of our engineers can speak English well, so the after sales service is easy for us.
All of LISUN products are fully meet the international lighting standards, not just the GB. The quality of the equipment would be relatively high.
Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.
Our main products are Goniophotometer, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.
Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com, Cell/WhatsApp: +8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp: +8618917996096
There is some other manufacturers in China also produce High and Low Temperature Humidity Chamber, and our equipment is mainly different from the following four points:
(1) Display temperature: We use Schneider or Omron’s relay. And the temperature that can be reached is the temperature under load. But many manufacturers refers to the temperature without load. If under load, the temperature must be different from the original temperature.
(2) Water purification device: To generate humidity inside the equipment, there must be distilled water. And there is a water purification device in our High and Low Temperature Humidity Chamber, so we can use tap water directly, to save the cost of distilled water. But many other manufacturers do not have water purification device in the machine.
(3) Temperature sensor: We use electronic temperature sensor, which can use for long time; while other domestic manufacturers use wire ball which is very easy to be bad to save costs.
(4) After-sales service: LISUN has engineers who visit our customers to do after-sales service all over the world, and all of our engineers can speak English well, so the after sales service is easy for us.
All of LISUN products are fully meet the international lighting standards, not just the GB. The quality of the equipment would be relatively high.
Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.
Our main products are Goniophotometer, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.
Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com, Cell/WhatsApp: +8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp: +8618917996096
Why should you choose a constant current power supply for the LED driver?
The LED is a light-emitting diode, and its characteristic curve is basically the same as that of a normal diode. When the applied voltage reaches the diode conduction voltage, the slight change of the applied voltage can cause a great change in the diode current. The constant current is used to ensure that the current in the LED is constant. No matter how the voltage changes, the current flowing through the LED does not change, which can ensure the life and light decay of the LED.
If a constant voltage source with an output of 12V is used, an electric 16 ohm resistor is connected in series to supply three strings of 0.5W 5630 lamp beads. The lamp voltage is calculated according to 3.3V, the current flowing through the lamp bead Io=(12-3*3.3)/16=0.131A, and the power of a single lamp bead is P=0.131*3.3=0.4323W. Because the temperature of the lamp bead is high The voltage of a single lamp drops to 3V. At this time, the current Io=(12-3*3)/16=0.187A, the current increases by 56 mA., and the power becomes P=0.187*3=0.561 W, which exceeds the lamp power consumption. In the long run, it has a great influence on the life and light decay of LED lamp beads.
Therefore, the key to affecting the life of the LED is the temperature. When the LED temperature rises, the junction resistance decreases, that is, the conduction voltage decreases. At the same voltage, an increase in temperature will cause the LED current to increase, and the current will increase the temperature further, so that the vicious cycle will burn the LED. Moreover, the light decay of LEDs is also related to temperature. When the temperature rises, the light decay is intensified, and the phenomenon of bright and bright is appearing.
There are two reasons for the temperature rise: First, the quality problem, the thermal conductivity of the LED package is poor, the temperature in the LED die is not transmitted to the surface (internal heat and cool), even if the heat sink is added, the internals cannot be completely The heat is dissipated, and then some low-end products do not add a heat sink; the second is the temperature rise caused by the power supply. When the LED is turned on, due to its nonlinearity, the weak change of the power supply will cause a sharp change in the LED current, resulting in temperature.
Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.
Our main products are Goniophotometer, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.
Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com,Cell/WhatsApp: +8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp: +8618917996096
If a constant voltage source with an output of 12V is used, an electric 16 ohm resistor is connected in series to supply three strings of 0.5W 5630 lamp beads. The lamp voltage is calculated according to 3.3V, the current flowing through the lamp bead Io=(12-3*3.3)/16=0.131A, and the power of a single lamp bead is P=0.131*3.3=0.4323W. Because the temperature of the lamp bead is high The voltage of a single lamp drops to 3V. At this time, the current Io=(12-3*3)/16=0.187A, the current increases by 56 mA., and the power becomes P=0.187*3=0.561 W, which exceeds the lamp power consumption. In the long run, it has a great influence on the life and light decay of LED lamp beads.
Therefore, the key to affecting the life of the LED is the temperature. When the LED temperature rises, the junction resistance decreases, that is, the conduction voltage decreases. At the same voltage, an increase in temperature will cause the LED current to increase, and the current will increase the temperature further, so that the vicious cycle will burn the LED. Moreover, the light decay of LEDs is also related to temperature. When the temperature rises, the light decay is intensified, and the phenomenon of bright and bright is appearing.
There are two reasons for the temperature rise: First, the quality problem, the thermal conductivity of the LED package is poor, the temperature in the LED die is not transmitted to the surface (internal heat and cool), even if the heat sink is added, the internals cannot be completely The heat is dissipated, and then some low-end products do not add a heat sink; the second is the temperature rise caused by the power supply. When the LED is turned on, due to its nonlinearity, the weak change of the power supply will cause a sharp change in the LED current, resulting in temperature.
Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.
Our main products are Goniophotometer, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.
Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com,Cell/WhatsApp: +8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp: +8618917996096
The differences of the test result between LISUN WT2080 LED power driver tester and multimeter when testing LED power driver
Some customers suspect the accuracy of the WT2080 because there is some differences of the test result between LISUN WT2080 LED Power Driver Tester and multimeter when testing LED power driver. In fact, the test results are different because the test principle is different: the WT2080 test result is the real effective value (RMS), the multimeter test result is the average value.
LISUN WT2080 is according to GB/T 24825-2009 and IEC 62384:2011. It can measure the following parameters: Input Characteristics Test (AC/DC), Output Characteristics Test (AC/DC), Start Characteristics Test (DC) and Hormanic Test. It is specified in the standard that the test result should be RMS.
The results of the general multimeter test are average values, so the test results are naturally different because of the different standards. WT2080 can print data and communicate with PC, displaying all the dates and curves in PC. There is also the average value in the test report, but on the display screen is RMS. Click here to learn more about the WT2080 LED Power Driver Tester.
Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.
Our main products are Goniophotometer, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.
Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com, Cell/WhatsApp: +8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp: +8618917996096
LISUN WT2080 is according to GB/T 24825-2009 and IEC 62384:2011. It can measure the following parameters: Input Characteristics Test (AC/DC), Output Characteristics Test (AC/DC), Start Characteristics Test (DC) and Hormanic Test. It is specified in the standard that the test result should be RMS.
The results of the general multimeter test are average values, so the test results are naturally different because of the different standards. WT2080 can print data and communicate with PC, displaying all the dates and curves in PC. There is also the average value in the test report, but on the display screen is RMS. Click here to learn more about the WT2080 LED Power Driver Tester.
Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.
Our main products are Goniophotometer, Spectroradiometer, Integrating Sphere, LED Test Instruments, CFL Test Instruments, Photometer and Colorimeter, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test , Dustproof Test Chamber, High and Low temperature Humidity Chamber, Plug and Switch Testing, AC and DC Power Supply.
Please feel free to contact us if you need any support.
Tech Dep: Service@Lisungroup.com, Cell/WhatsApp: +8615317907381
Sales Dep: Sales@Lisungroup.com, Cell/WhatsApp: +8618917996096
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