Salt Spray Corrosion Test

 ISO is the worldwide union of national standards. The international standard ISO 9227 has been developed by the ISO/TC 156 Metals and Alloys Corrosion Technical Committee. There are many factors affecting metal corrosion. A single salt spray resistance cannot replace the performance of other media, so this standard cannot be used as a direct guide to the corrosion resistance of the tested materials in all environments. At the same time, the performance of various materials in the test can’t be used as a direct guide to the corrosion resistance of these materials in use. Nevertheless, the method specified in this standard can still be used as a method to test the material with or without corrosion resistance.

This standard specifies equipment, reagents and methods used in neutral salt spray (NSS), acetate spray (AASS), and copper accelerated acetate spray (CASS) tests. A method of assessing the environmental corrosivity of the test chamber is also specified.

The materials of the experimental equipment must be resistant to salt spray corrosion and do not affect the experimental results. The salt spray box volume is not less than 0.2m³.

LISUN YWX/Q-010 salt spray test chamber (Figure 1) uses transparent materials to allow the user to observe the spray conditions in the test chamber and the sample to be tested. A waterproof structure is adopted between the box and the cover to prevent salt liquid from overflowing. The device has a smart touch screen and is easy and fast to operate.

 

YWXQ-010 Salt Spray Test Chamber

The Salt Spray Test Chamber is applicable to the salt spray corrosive test for the protection layer of components, parts, electronic and electrical parts and metal materials and industrial products. It meets the following standards: IEC60068-2-11 (GB/T2423.17), GB/T10125, GB/T1771, ISO9227, ASTM-B117, GB/T2423-18, QBT3826, QBT3827, IEC 60068-2-52, ASTM-B368, MIL-STD-202, EIA-364-26, GJB150, DIN50021-75, ISO3768, ISO 9227, 3769, 3770; CNS 3627, 3885, 4159, 7669 etc.

We can manufacture different size of salt spray test chamber according to the customer test product size. The specification detail is below:

Model	Work Room Size (mm)	Exterior Size (mm)	Voltage	Power (KW)
YWX/Q-150	600x450x400	1100x750x930	1Phase/220V	2
YWX/Q-250	900x600x500	1500x900x1150	1Phase/220V	2.5
YWX/Q-750	1100x750x500	1700x1050x1150	1Phase/220V	3.5
YWX/Q-010	1200x800x500	1800x1100x1200	1Phase/220V	3.5
YWX/Q-016	1600x900x600	2300x1300x1300	1Phase/220V	5
YWX/Q-020	2000x1000x600	2700x1400x1500	3Phase/380V	7.5

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, Surge Generator, EMC Test Systems, ESD Simulator, EMI Test Receiver, Electrical Safety Tester, Integrating Sphere, Temperature Chamber, Salt Spray Test, Environmental Test Chamber, LED Test Instruments, CFL Test Instruments, Spectroradiometer, Waterproof Test Equipment, 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

Test Post from LISUN

Test Post from LISUN
https://www.lisungroup.com

LED Lamps Aging and Life Test

Many customers need aging LED lamps, but do not have a clear concept of aging test and life test.

Aging test usually use aging test racks. What is aging test rack? Aging rack is dedicated to simulate the products in real conditions involved in the use of various factors on the aging of the product conditions to strengthen the process of the corresponding conditions.

Why we need aging test? Electronic products, no matter components, parts or machines, all need aging test. Aging and test is not one concept, aging firstly and then test. Electronic product after manufacturing forms a complete product, which is able to play its role. But users may find a variety of problems after use, most problems occurs in the first few hours to dozens of hours. Later, formulate electronic products aging and test to simulate the using state or equivalent products. This process is done by the product manufacturer.

The problem products will stay in factory, products without problems will sell to users, to ensure that the products that users buy are reliable or less problematic, which is the meaning of aging test.

LED life and reliability of LED products is one of the most important performances. Life is the ultimate performance of reliability, but the theoretical life of LED is very long, according to the use of different conditions and drive current, LED life has 50.000 hours or more. Different with the traditional light source, LED will not go out instantly, but decays slowly. According to LM-80, LED light source should operate at the lowest temperature of the three case temperatures (Ts) for the photometric test and should use the same drive current. These three case temperatures should be 55℃, 85℃ and a third temperature provided by the DUT manufacturer. The case temperature provided by the DUT manufacturer and drive current should meet the customers’ requirements and are within the recommended operating temperature range. Test unit should be driven for at least 6000 hours and the data collected at least every 1000 hours.

Rated Lumen Maintenance Life is the elapsed operating time over which the LED light source will maintain the percentage of its initial light output. The lumen maintenance rate is a contradiction of the flux attenuation.
Lisun LEDLM-80PL LED Lumen Maintenance and Aging Life Test System is designed according to standards of IES-LM-80, IES-LM-82, TM-21 and GB2312-80.

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

Surge generator: IEC 61000-4-5-2014 Surge Immunity Test

The International Electrotechnical Commission (IEC) has published IEC 61000-4-5:2014, “Electromagnetic Compatibility (EMC) – Part 4-5: Testing and Measurement Techniques – Surge Immunity Test.”

“IEC 61000-4-5:2014 relates to the immunity requirements, test methods and range of recommended test levels for equipment with regard to unidirectional surges caused by over-voltages from switching and lightning transients. Several test levels are defined which relate to different environment and installation conditions. These requirements are developed for and are applicable to electrical and electronic equipment. The object of this standard is to establish a common reference for evaluating the immunity of electrical and electronic equipment when subjected to surges.”

“The test method documented describes a consistent method to assess the immunity of an equipment or system against a defined phenomenon. This standard defines a range of:

• test levels;
• test equipment;
• test setups;
• test procedures.”

“The task of the described laboratory test is to find the reaction of the equipment under test (EUT) under specified operational conditions to surge voltages caused by switching and lightning effects. It is not intended to test the capability of the EUT’s insulation to withstand high-voltage stress. Direct injections of lightning currents, i.e. direct lightning strikes, are not considered in this standard.”

“This third edition cancels and replaces the second edition published in 2005, and constitutes a technical revision which includes the following significant technical changes with respect to the previous edition:

• a new Annex E on mathematical modelling of surge waveforms;
• a new Annex F on measurement uncertainty;
• a new Annex G on method of calibration of impulse measuring systems;
• a new Annex H on coupling/decoupling surges to lines rated above 200 A.”

“Moreover, while surge test for ports connected to outside telecommunication lines was addressed in 6.2 of the second edition (IEC 61000-4-5:2005), in this third edition (IEC 61000-4-5:2014) the normative Annex A is fully dedicated to this topic. In particular, it gives the specifications of the 10/700 µs combined wave generator.”
LISUN SG61000-5 Surge Generator is exactly according to the latest version of this IEC standard.
SG61000-5_Surge Generator

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 System, LED Test Instruments, EMC & EMI Testing, Surge Generator, Electrical Safety Testing, Environmental Test Chamber, Waterproof Test ,Dustproof Test , High and Low temperature Humidity Chamber, Plug and Switch Testing,etc.


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 3M Integrating Sphere Test Results Comparison with Third Party Laboratory

Lisun engineers visited Barcelona recently, this visit was mainly to install the 3m Integrating Sphere Test System for the customer and provide training service.
This customer compared the test results of Lisun’s 3m Integrating Sphere Test System with the test results of Holophane(HEL) and LIA Laboratories. This customer provided 4 samples to the third lab. Compared with LIA Laboratories, our tolerance are controlled within 5%:
HAL – LED Highbay: 4.6%
VMX LED Luminarie: 2.3%
Corn Lamp: 2.5%

Platek – Target Medium Prioette LED Luminaries: 0.5%


The test report of Platek tested by Lisun 3m Integrating Sphere Test System
The test report of Platek tested by LIA Laboratories-1
The test report of Platek tested by LIA Laboratories-2

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

Can we use LMS-6000 portable CCD spectroradiometer to test luminous flux lumen?

With the rapid development of LED lighting market, the competition becomes more and more intense. So more and more LED lighting manufacturers began to focus on the quality of their products in order to gain a greater share in the market. Thus, LED lighting test instruments became the indispensable equipment. On the LED test equipment, there are goniophotometer, integrating sphere, spectroradiometer, LED driver power tester, EMI & EMC test equipment, and IP waterproof, dustproof environmental test chamber and so on.

And goniophotometer, integrating sphere and spectroradiometer is the most common and also basic equipment, mainly used to test the LED luminaires photometric, colorimetric and electrical performance, such as lumen (luminous flux), luminous intensity distribution, luminous efficiency, correlated color temperature, color rendering index, voltage, power and other basic parameters. However, due to the price of these equipment is not cheap and it requires a certain size of the laboratory, many small and medium-sized manufacturers or companies that started LED industry turned to seek portable test equipment, such as LMS-6000 Portable CCD Spectroradiometer. There are various kinds of portable spectroradiometers on the market, with elegant appearance and built-in high resolution LCD display, and even can be as smart as the phone. But is it really capable of testing lumens?

Many portable spectroradiometers claim to be able to test the lumen value of LED lamps. However, according to the standard IES LM-79-08 Electrical and Photometric Measurements of Solid-State Lighting Products, in Section 9.0, it states that the total luminous flux (lumen) of the SSL product should be measured using an integrating sphere system or goniophotometer. As for which method to use, depending on the size and shape of SSL products, and whether needs to measure other parameters such as color, luminous intensity distribution and so on. In general, the integrating sphere system is suitable for testing integrated LED lamps and relatively small LED luminaires (refer to Section 9.1.2 about the method for measuring the size of SSL products measured with the specified size of the integrating sphere) total luminous flux and colorimetry. The integrating sphere system has the advantage of fast measurement and no darkroom, and the result of the total luminous flux is a relative value because the final measurement result is calculated by comparison with the reference standard. Goniophotometer is usually used to measure luminous intensity distribution, and then resulting total luminous flux, thus it is an absolute value, and the measurement results are more accurate. It can measure the total luminous flux of not only small SSL products but also relatively large (as opposed to traditional fluorescent lighting) SSL products. Goniophotometer needs to be installed in the usual temperature control of the darkroom, to avoid the measured light source to absorb heat and other stray lights’ reflection to affect the measurement results.

Therefore, theoretically using a LMS-6000 Portable CCD Spectroradiometer to test lumen is not feasible, because the lack of the corresponding test environment, the measurement results will be a great error. In order to fulfill customers’ requirement of testing luminous flux (lumens) with limited budget, Lisun developed an economical compact integrating sphere spectroradiometer system, to provide customers with the best solution. The LPCE-3 CCD Spectroradiometer Integrating Sphere Compact System integrates the equipment and cabinet into ALL-IN-ONE, so there’s no need to install, and it is more convenient and easy to operate. Also it saves a lot of space. The sphere can be dismantled into two parts, which is easier for transportation, especially at offices or laboratories with smaller door sizes. In addition, this integrating sphere comes with a removable test holder base inside, and it can withstand 20kg weight. Also, it can install and replace different light fixtures for measurement according to different types of light sources, which is very simple and convenient, please refer to the following figures.
LPCE-3_ CCD Spectroradiometer Integrating Sphere Compact System LPCE-3 CCD Spectroradiometer Integrating Sphere Compact System LPCE-3 CCD Spectroradiometer Integrating Sphere Compact System

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 predict and test the life of LED?

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

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

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

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

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

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

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

How to choose LISUN products for Saudi Arabia’s latest standard SASO2902

Recently Saudi Arabia released new LED standard SASO 2902 for energy efficiency, functionality and labeling requirements for Lighting products. We have got the SASO 2902 in 2017 which is draft and already produce some instruments for some of the Saudi Lab. Such as below products:

1. LPCE-2(9000B) High Precision Spectroradiometer Integrating Sphere System. It can test EEI, Energy Efficiency Class, SDCM, CRI, CCT, Lumen and so on.

2. LSRF-3 Lamp Start, Run-up time and Flicker Tester, which meet Table 13 (on page 27) in SASO2902. The LSRF-3 can be used with LISUN LPCE-2 High Precision Spectroradiometer Integrating Sphere System.

3. LSG-5000 LM-79 Moving Detector Goniophotometer. This test system can make the measurement of Luminous Intensity Distribution, Luminaries Efficiency, Luminance Distribution, Efficient Luminescence Angle, UGR and etc. The test result can be exported as CIE, IES, LDT and other format files.

4. SY2036 Aging and Life Test Rack which is special designed for Saudi Arab to meet SASO2902 in clause 5.2.

5. LEDLM-80PL LED Lumen maintenence and endurance test system, which meet SASO2902 in clause 5.2.

6. WT2080 LED Driver Test System

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

Contents and Meanings of EMC Test According to International Standards

Electromagnetic Compatibility EMC refers to the ability of a device or system to function properly in its electromagnetic environment and does not constitute an electromagnetic disturbance to anything in the environment. Sensor electromagnetic compatibility refers to the adaptability of the sensor in the electromagnetic environment, maintaining its inherent performance and the ability to perform specified functions. It contains two requirements: on the one hand, the sensor should not cause electromagnetic interference to the environment in the normal operation process, and the sensor must have a certain degree of immunity to the electromagnetic interference in the environment.

 

Figure 1: the classification of EMC 

Figure 2: The Schematic of EMC

Introduction of products
1. Conducted radiation interference
The RF interference frequency range emitted by this standard covering equipment is 9KHZ-400GHZ. The limits in this standard are determined on a probabilistic basis so that disturbances are suppressed within economically reasonable limits while still achieving adequate levels of radio protection and electromagnetic compatibility. In exceptional cases, additional requirements may be made. The EMI Test System EMI-9KC/EMI-9KB fully meets CISPRl6-1, GB17743, FCC, EN55015 and EN55022.
EMI-9KA/9KB EMI Receiver System is a main test system for EMI (Electro Magnetic Interference) testing.

2. Static Immunity
The International Electrician Commission (IEC) has issued IEC 61000-4-2 version 2.0 (2008-12) entitled “Electromagnetic Compatibility (EMC) – Part 4-2: Test and Measurement Techniques – Electrostatic Discharge Immunity Test”.
This standard covers the immunity requirements and test methods for electrical and electronic equipment subjected to electrostatic discharge, including from equipment to direct operators, from personnel to adjacent objects. In addition, it defines the range of test levels for different environments and different installation conditions, and establishes test procedures. The purpose of this standard is to establish a common and repeatable benchmark for evaluating the performance of electrical and electronic equipment when subjected to electrostatic discharge. It also lists statics that may occur in objects near people and critical equipment, as well as typical waveforms of discharge current, test range, test equipment, test setup, test procedures, calibration procedures, and measurement uncertainty.
The second edition of the standard replaces the first edition published in 1995, and its amendment 1 (1998) and its amendment 2 (2000) together constitute a technical revision that is fully compliant with the basic IEC EMC guidelines 107.
Electrostatic Discharge Simulator (Electrostatic Gun) from LISUN is in full compliance with IEC 61000-4-2, EN61000-4-2, ISO10605, GB/T17626.2, GB/T17215.301 and GB/T17215.322.

3. RF Radiation Immunity
The international standard IEC61000-4-3 was drafted by the 65A subcommittee of the IEC Technical Committee 65 and replaced IEC801-3 published in 1984.
Electromagnetic radiation affects most electronic devices in some way. In addition to intentional electromagnetic energy, some devices generate stray radiation, such as electric welders, thyristor rectifiers, fluorescent lamps, and the like. This interference is manifested in most cases as conducted interference, which is involved in other standards of this series of standards. Methods to prevent the effects of electromagnetic fields often also reduce the effects of such sources of interference.
SDR-2000B Magnetic Shielding Chamber for EMI from LISUN is fully compliant with IEC61000-4-3 and has a suitable size to maintain a uniform field with sufficient space relative to the EUT.

4. Electrical Fast Transient Burst Immunity
The international standard IEC61000-4-4 was developed by the 77B subcommittee of the IEC Technical Committee 77. The purpose of this standard is to evaluate a common reproducible basis for assessing the performance of electrical and electronic equipment’s power supply ports, signals, and control ports in the presence of repetitive fast transients. However, the test of special equipment or systems is not regulated. The repetitive fast transient test is a test that couples a burst of many fast transient pulses to the power ports, signals, and control ports of electrical and electronic equipment. The main points of the test are short rise times of transients, repetition rates and low energy.
EFT61000-4 EFT Immunity Tester from LISUN is developed for the requirements of fast transient burst immunity tests and is the ideal source of interference for EMS measurements.

5. Surge Generator Immunity
The international standard IEC61000-4-5 was developed by the 65th Subcommittee of the IEC Technical Committee 65. This standard has the status of a basic electromagnetic compatibility publication. The immunity requirements for the unipolar surge caused by the switch and lightning transient overvoltage, the test method and the recommended test level range are specified, and several test levels related to different environments and installation conditions are specified.
Automatic Lightning Surge Generator (or Lightning Surge Immunity) SG61000-5 is used to assess the power cord and connect the internal switch stood in line to connect the internal switch to provide a common basis for switching the natural world and lightning caused by the high-energy transient interference performance.

6. RF Conducted Immunity
The international standard IEC61000-4-6 was developed by the 65A subcommittee of the IEC Technical Committee 65 and the 77B subcommittee of the IEC Technical Committee 77. In accordance with IEC Guide 107, it has the status of a basic EMC publication. This standard relates to electrical and electronic equipment requirements for electromagnetic immunity from RF transmitters in the frequency range from 9KHZ to 80MHZ. The device is coupled to the RF field by a cable.
The source of disturbance referred to in this standard usually refers to the electromagnetic field from the RF transmitter. This electromagnetic field may act on the entire cable that connects the mounting equipment. Although the size of the device being harassed is smaller than the wavelength of the disturbance frequency, the output and input lines may become passive receiving antenna networks because their length may be several wavelengths.
The RFCI61000-4-6 RF Conducted Immunity Test System from LISUN is mainly used for conduction sensitivity testing.

7. Power Frequency Magnetic Field Immunity
The international standard IEC61000-4-8 was developed by the 77B subcommittee of the IEC Technical Committee 77. This standard is the eighth part of the fourth part of IEC61000, which has the status of a basic EMC publication in accordance with the IEC107 guidelines. This standard specifies the immunity requirements of equipment under operating conditions for power frequency magnetic field disturbances in the following locations: residential and commercial areas; industrial and mining areas and power plants; medium voltage and high voltage substations. For equipment installed in different locations, the applicability of this standard is determined by the phenomena indicated in Chapter 3. The purpose of this standard is to establish a common and reproducible benchmark to evaluate the performance of electrical, electronic, and electronic equipment used in power frequency magnetic fields. The power frequency magnetic field is generated by the power frequency current in the conductor, or a very small amount is generated by other devices in the vicinity.
PFM61000-8A Magnetic Field Generator from LISUN is a high stability energy test equipment mainly used for electronic product design requirements of immune characteristics and normal frequency magnetic field testing requirements.

8. Voltage Drop Immunity
The international standard IEC/EN61000-4-11 was drafted by the 77B subcommittee of the 177th Technical Committee of the IEC. This standard is Part 11 of Part 4 of IEC61000 and is a basic EMC standard in accordance with IEC Directive 107. This standard specifies the immunity test method and preferred test level range for voltage sag, short interruption and voltage change of electrical and electronic equipment connected to the low voltage power supply network. This standard applies to electrical and electronic equipment with a rated input current of no more than 16A per phase. The purpose of this standard is to establish a general guideline for evaluating the immunity of electrical and electronic equipment to voltage dips, short interruptions and voltage changes.
CSS61000-11 Voltage Dip and Interruptions Generator from LISUN is a highly reliable device specially designed for the characteristics and requirements of voltage dip and short-term interrupt immunity test.

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 Methods and Principles for LED Lighting EFT Immunity Measurement According to IEC 61000-4-4

When doing IEC 61000-4-4 EFT immunity test, there are L1, L2, L3, N and PE interface. PE and earth are two different concepts. Electrical fast pulse interference is common mode, in the experimental setup figure of the standard, we can see the signal cable which is from the test generator can connect with corresponding power lines (L1, L2, L3 , N and PE) through the selectable coupling capacitor, and the signal cable shield connects with the chassis of coupling/decoupling network, and the chassis is connected to the reference ground terminal.

This indicates that burst interference is actually applied between the power line and the reference earth, so the interference which is added on the power line is common mode interference, and for the experimental method of using coupled folder, the electrical fast pulse will be added into the tested cable through the distributed capacitance which is between coupling plate and the tested cable. But the pulse which tested cable received is still relatively to the reference ground plane.
Thus, the interference applied on the tested cable by coupling clamp is still common mode. After confirming the nature of the interference, we can take the appropriate measures to make the equipment passed the test. So we can see, the X capacitor (differential mode capacitor) which used in power filters cannot inhibit EFT interference.

If the device included metal shell, the Y capacitors (common mode capacitance) will work. We can bypass the high frequency EFT to the shell, and then back to the signal source via the distributed capacitance which between the device shell and the reference ground, so as not to enter the circuit.
The mechanism of electrical fast pulse interference causes equipment failed, according to foreign scholars’ research, the single pulse energy is small, it will not cause malfunction of the equipment. However, the interference signal of burst charges apparatus line junction capacitance, when the above energy accumulated to a certain extent, it is possible to cause malfunction of the power line (as well as the system).

Therefore, there will be a time process for the line error, and there will be some chance (cannot guarantee the time interval of the error, especially when the tested voltage reaches the critical point). And it is difficult to judge whether the device is more likely to fail for separately applying a single pulse or applying pulse group together. And it is hard to say whether the device is more sensitive for positive pulses or negative pulses.

Practice shows that one device is usually particularly sensitive to a polarity of a power cable under a certain kind of tested voltage. Experiments show that the signal line is much more sensitive than the power line for the electrical fast pulse interference.

Effective measures for equipment passing the electrical fast pulse test. First we analyze the methods of interference injection: EFT interference signal is coupling to the main power lines by coupling the 33nF capacitance of decoupling network (and the signal or control cables applies interference through capacitive coupling clamp, the equivalent capacitance is 100pF). For 33nF capacitance, it’s cutoff frequency is 100K, which means

The interference signal which is more than 100KHZ can be passed; but for 100pF capacitance, the cut-off frequency is 30M, only allows interference whose frequency is more than 30MHz passed. The interference waveform of the electrical fast pulse is 5ns / 50ns, repetition frequency is 5K, pulse duration is 15ms, burst repetition period is 300ms. According to the Fourier transform, its spectrum is from 5K to 100M discrete spectral lines, and the distance between each spectral line is the pulse repetition frequency.

After the above, we can know that the coupling capacitance which applies the interference plays a role of a high-pass filter, because the impedance of the capacitance decreases as the frequency increases, the low-frequency in the interference will not be coupled to the EUT, only the interference signal with higher frequencies will enter the EUT. When we add the common mode inductance into the EUT circuit (with particular attention to that, the common mode inductance must be added to the main power line and its return line or it will reach saturation and thus cannot reach the purpose of attenuating interference), it will attenuate some of the high frequency interference, because the impedance of the capacitance increases as frequency increases. Therefore, the interference signal which actually applied to EUT only left the intermediate frequency.

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 LED Driver RMS Value Measurement and Analysis

As we known the quality of LED lighting products depend on two points: One is LED chip(light source); Second is LED power driver. In the practice, there only have few company can provide qualified LED chip such as PHILIPS, OSRAM and CREE in the market. Generally, the LED chip have very small change to get quality problem, but we heard many news about low quality LED lighting products was found and caused big losses to customers because of un-qualified LED driver. As considering the importance of LED driver, this article will discuss some technical introduction and measurement technology.

There have some necessary test items of LED Power Driver Tester such as Crest Factor, Effective Power, Reactive Power, Apparent Power, Power Factor, Voltage/Current (RMS value, Average value) and THD harmonic parameters etc. In the practice measurement, lots of people found it have big difference between get from LED driver tester and multimeter, and this difference focus on Voltage/current rms, apparent power, power factor, RMS(rms) and average. Many users feedback the voltage/current(RMS date) from multimeter is lower or bigger than LED driver tester, it is necessary to make a explain here that the values from LED driver tester are RMS(true and effective value), the average curren we often talking is also RMS(average value), the average current only can get when it satrt test and it is RMS average value during start process; the software data is keep some with front panel of LED driver tester. In the meantime, according to international standards, the RMS(true and effective value) is needed only when test LED driver, it is meaningless to measure average value. The LED driver tester will show voltage, current and power, but the power is not equal of voltage multiply current; the voltage multiply current directly get inspecting power, the LED driver tester showed value is active power. If only use multimeter to measure average value, then there is no need use professional LED driver tester. According to IEC 62384 standard, the Voltage True RMS (Vrms), True RMS Current (rms), Active Power (P) and Power Factor (PF) calculate way as below:
In the above formula, “N” is stand the number of sampled points during the period (the period depends on the frequency of the signal to be measured) and the value at a certain sampling time. The LED driver tester provides two test methods to calculate the total harmonic distortion (THD), namely IEC and CSA, respectively:
In the above two formulas:
THD: Represents the relative value of voltage/current total harmonic distortion
C：Represents the K times harmonic effective value of the voltage or current
K：Number of harmonics
N：The maximum harmonic frequency (This LED driver tester is 50)
C：RMS value of fundamental voltage or current (ie, 1 harmonic)
In the practice measurement, when use RMS value or average value of LED constant output current to judge quality of LED driver, there have two ideas in the market: some use RMS value but some use average. Caused this two difference idea due to LED driver have big current ripple and each LED driver is different, then the RMS value and average value of output current have big difference, but according to the actual situation and standards, the only judge factor is focus on RMS value, we can refer average value but can's see it as key judge factor.

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