Frequently Asked Questions 

Welcome to our Frequently asked questions (FAQs)

There are lots of questions concerns LED Lighting fittings here, so we have grouped them into different headings. If you don't find the answer in one section, try another similar one. or contact our team members for help.

General questions

Why is LED technology classified as solid state lighting?

The term solid state lighting is used because the electronics produce light directly from solid materials in which the electrons are embedded. This is unlike other technologies, for example fluorescent technology, which requires a gaseous discharge medium to initiate production of light. 

What makes LEDs more robust than other light sources?

LEDs have no gases, filaments and no moving parts to fatigue. They provide light through a one-step process that takes place within the diode. There is no glass to break or screwed contacts to loosen. 

Why do LEDs have a higher initial cost than conventional light sources?

LEDs are made of electronic components that need to be packaged together to offer long lasting efficient light sources to the end user. Apart from the LED chip itself which has sapphire and gallium in the semiconductor, the process of packaging with materials like ceramic, rare earth phosphors, silicone, solder and gold wire add to the overall cost. White LEDs require further tests for calibration and standardization. 

What are the economic advantages of using LEDs over conventional light sources?

Although the initial cost of conventional light sources is less than LEDs, the operational and maintenance costs of LED are significantly lower. LEDs, having a longer life, reduce maintenance and lamp replacement cost. . Because LEDs need to be replaced less frequently, the owner spends less on new lamps and the labor needed to change them. LEDs also consume less energy; thus the overall cost of a LED system can be significantly lower than that of conventional lighting systems. Most applications with LEDs offer a payback period as low as three to four years. 

Can I use LEDs in a green house?

LEDs can produce concentrated beams of light at specific frequencies of light. While sunlight comprises the entire spectrum of light, LEDs can be designed to emit specific parts of the light spectrum that activate certain photoreceptors in the plant. For example, blue light promotes phototropism and cryptochromes which help germination and elongation of the plant, while red light stimulates phytochromes which help the plant to flower at the optimum time. Regulation of the spectrum of light based on the plants life cycle promotes faster growth, and a stronger plant than what would be produced under sunlight conditions.

Note that the light output of LEDs lessens at higher temperatures. You should make sure that the luminaire is suitable for the environmental conditions. 

Is it true that LED lights do not attract insects?

Most insects are primarily attracted to Ultra-violet rays, which help them forage, navigate and select mates. For example, Indian moths are attracted to UV-365nm and green light-500nm. LEDs do not have UV content and hence do not attract many insects compared to conventional light sources. 

How do LEDs keep food fresher than conventional light sources?

LEDs do not emit ultra-violet light and do not carry heat in the beam, unlike their conventional counterparts. This helps keep food fresher in refrigerators and cold stores. 

What are the advantages of LED over neon in signage applications?

LEDs have the following advantages over neon:

How can the color changing ability of LEDs be advantageous in retail and display environments?

In retail and display environments where the range of products change by the season, the colors can be changed to match the type of product on display. For example, electronic goods may require a cool white light while a warmer tone may be required for fabrics. When a fashion season has red as a theme, the store can utilize a color of light with more red in its spectrum to enhance and bring out the vibrancy of the display. 

Can LEDs help to improve performance in classrooms?

LEDs have the capability to offer “biologically optimised” solutions that simulate the color temperature of the sky. This have been proven to improve concentration and maintain alertness of students in classrooms. It has successfully dealt with a kind of morning tiredness in mostly observed in young people. One way of creating the  appropriate color temperature is by using a combination of independently controlled blue and white LEDs. 

What are the benefits of using LEDs in mining areas specifically?

Using LEDs in mining areas has the following benefits:


What are some of the uses of LED colored lights in the defense industry?

Green LEDs of wavelength 495nm along with red LEDs are useful for military pilots who have special devices that are made for night vision. Blue LEDs are useful for pilots who need to read maps at night. Special infra-red LEDs are used to light areas at night without making the target aware that they are being viewed. This is facilitated through special IR night vision equipment. 

Why are LEDs advantageous in lighting underground caves?

Underground stalactites are damaged by the heat of halogen lamps. LEDs, with their long lifecycle also require much less maintenance than traditional light sources. 

White light & other colors

How is white light produced by LEDs?

LEDs do not directly produce white light. There are two ways in which white light is produced from LEDs as below:

Using a blue LED with a phosphor coating to convert blue light to white light by a process called fluorescence.

Combining red, blue and green LEDs to produce white light. White light is produced by varying the intensities of the individual red, blue and green chips.

What are tunable white LEDs?

Tunable white LEDs are light engines that combine individual chips to produce a range of CCT from warm white and cool white. 

How is colored light produced from LEDs?

The color of light produced is dependent on the inorganic material used in the P-type and N-type semiconductors (organic material in the case of O-LED). Different inorganic materials in the semiconductor release different amounts of energy when the LED is connected to a power supply. The amount of energy released defines the color of the light produced. For example, red is a low energy light and blue is a high energy light.

Why do LEDs produce more vibrant and saturated colors than conventional lamps?

LEDs emit a very narrow spectrum of light. The type of material used in the semiconductor permits only a specific wavelength of light (one color) to be emitted when electrons cross the junction. 

What does RGB LED mean?

RGB LED means red, blue and green LEDs. RGB LED products combine these three colors to produce over 16 million hues of light. Note that not all colors are possible. Some colors are “outside” the triangle formed by the RGB LEDs. Also, pigment colors such as brown or pink are difficult, or impossible, to achieve. 

What are the different types of RGB LEDs?

The following are the different types of RGB LEDs:

How is Amber produced?

This is a phosphor - converted Amber LED. Amber uses special phosphors in combination with royal blue LED chips. 

What does correlated color temperature, CCT, mean?

Color temperature(CCT) defines the color appearance of a white LED. CCT is defined in degrees Kelvin; a warm light is around 2700K, moving to neutral white at around 4000K, and to cool white, at 5000K or more. Note that CCT does not tell you anything about the color rendering ability of the LED. 

What are the standard comparisons used to evaluate the color quality of light sources?

In what contexts do R-9 values of CRI of LED lamps become important?

CR-9 represents red tones, which are prevalent in skin tones, clothes, vegetable and meat. For make-up rooms, supermarket and grocery meat and vegetable counters, if the same visual freshness as seen with halogens and incandescent lights sources is required, looking into R-9 values of LEDs is a must. Usually, gallery owners and artists will easily note the difference in effect when red tones are prevalent in the art work. 

What is the SPD of a light source?

SPD is the Spectral Power Distribution of a light source. The visible white light that we see is made up of a spectrum of various colors of light, ranging from wavelengths of 380nm (violet) to 760nm (red). The SPD is a graph that shows the power (strength) of each wavelength of light produced by a particular light source. 

What quality processes guarantee the consistency of the color appearance of LEDs?

LEDs are standardized for consistency in color and performance through a process called binning, and they are classified further in the MacAdam steps. During the manufacturing process LEDs are allocated to specific 'bin' numbers based on tests conducted to determine their color, lumen output and forward voltage. LEDs from each bin are further classified in a 7-step MacAdam ellipse. 

What other parameters can be used to evaluate the color quality of light?

Apart from CRI, R-values and CQS, color consistency is also a measure of the quality of light. The color consistency can be evaluated at several levels as follows:

Why do some white LEDs start emitting an almost bluish tone over time?

The white LEDs are made of phosphor coated blue LED chip. The degradation of the phosphor layer over time causes the bluish tone of the light emitted. This degradation is most likely to be caused by the chip running too hot. Remote phosphor technology overcomes this issue. 

Why has the color appearance of the LEDs changed after a period of use?

There are several possible reasons why this happens:

New LED Light source Life span & Output

What are the core components of a typical LED that gets soldered to a Printed Circuit Board?


A typical LED is made with a chip, which is the semiconductor that produces the light when electrically connected. The chip is connected by a very thin bond wire to a lead electrical contact that acts as the cathode. The chip is bonded with a thermal heat sink and a ceramic base. The chip is enclosed by a lens that not only protects the chip, but also modulates the light beam to the desired angle, depending on the nature of the lens. For production of white light, the chips are coated with phosphors.

Do LEDs require time to reach maximum brightness?


No. LEDs directly convert electrical energy to photons. It is a one step process of electroluminescence that does not require time to reach maximum output. Other sources such as fluorescents or HID, work on discharge technology. This requires an arc to warm up and may take a few minutes to reach full output.

What does a life of 50,000 hours mean in the case of - LEDs?


50,000 hours would imply 5.7 years if the light is operated for 24 hours in a day, 7.6 years if the lights are on 18 hours per day and 11.4 years for 12 hours a day.

Why is the life of LEDs measured as lumen depreciation?


Unlike conventional light sources that reduce in output and eventually fail, LED products do not normally suddenly fail. Instead, the light output reduces over time.

The normal convention is to measure the life from when the output has reduced by 30%, i.e. when there is 70% light output remaining. This is often quoted as the L70 life and is measured in hours.

What are the factors that affect the lifespan of the LEDs?


The thermal management of the LEDs. If LEDs come on a standalone chip, appropriate heat sinks have to be designed to prevent premature failure of LEDs.

The electrical stress: Running LEDs at currents higher than specified make the LED run hot. This can happen with wrongly matched drivers. For example, if the driver produces 700mA but the LED needs 350mA, this will put stress on LED and reduce its lifespan.

Higher ambient temperatures than the ones that the LED is rated for will reduce its expected life.

Is lifespan reduced if the LEDs are frequently turned on and off?


Unlike discharge lamps, LEDs are semiconductors and their life span is not affected by the number of times they are turned on and off.

How much longer does an LED last than a conventional light source?


Typically, an LED will last four times longer than a CFL and 25 times longer than an incandescent source that puts out the same amount of light.

What is the best way to compare the output of LEDs with other light sources?


Sometimes simply comparing the lumen output of LEDs and conventional light sources may not be adequate. The amount of light falling on a specific task area (the lux) gives a more realistic comparison. You should also consider the amount illumination visible on the walls. This helps identify applications where LEDs offer better solutions than other light sources.

Does increasing the wattage of LEDs increase their output?


This may occur if you are using the same product from the same brand, with the same optics and hardware. However, in general, the nature of the components (like the optical system, the heat sink, the LED chip, and the driver) affects the output more than the wattage does. A 3watt LED luminaire from one manufacturer will have a different output to a 3watt LED luminaire from another manufacturer, even if the same LED chip is used. Hence, using a high quality chip alone does not guarantee better performance. Note that as the wattage increases, the efficiency drops slightly. An LED driven at 3W will emit slightly less than three times the output of one driven at 1W.

Why are LEDs considered more efficient than conventional light sources?


When comparing the lumen output between LEDs and conventional light sources, LEDs may have lower lumen value in many cases. However LEDs are directional light sources, all the lumens emitted from an LED are directed towards the task area. Conversely, conventional sources emit light in all directions. The light is then modulated in a given direction with optical systems like reflectors and lenses. The amount of lumens that falls in the intended task area from an LED light source is greater than that of a conventional light source.

What are “cold” and “hot” lumens?


These terms do not have any photometric or engineering meaning. However, "cold lumens" is the light output of the LED chip alone when it is first switched on. "Hot lumens", refers to the light output of the LED when it is fully warmed up in the luminaire. The hot lumen value may be 30% - 50% lower than the cold lumen value.

How are LEDs different from other light sources in the way they produce light?


LEDs produce light by direct conversion of electrical energy to light energy.

On the other hand incandescent light sources produce light by heating a filament until it grows red hot. Linear and compact fluorescent lamps use a UV discharge plus a phosphor to produce the light. HID lamps use the ionization of gases in a discharge tube which in turn produce photons.

What are O-LEDs?


O-LEDs are organic light emitting diodes. They are made of carbon based films sandwiched between two electrodes; one is a metallic cathode and one is a transparent anode, which is usually transparent glass.

What are the characteristics of O-LEDs that make them different from other light sources?


O-LEDs are thin, flat, two dimensional surfaces offering a soft, glare-free luminous surface. Some versions of OLED are flexible. They can be transparent, mirrored or diffused when not electrically connected.

What are some new uses of LEDs that have appeared with the advent of OLED technology?


With the further increase in performance characteristics of LEDs and the advent of OLEDs the application sector of LEDs has expanded. Below are some of the new uses of LEDs:

Luminous walls and ceilings

Transparent walls and partitions that turn opaque at different times of the day.

Solar powered fabrics

Luminous garments

Power supplies/LED drivers

Why do LEDs require power supply / drivers?

LEDs are low voltage devices. Therefore, they require a device / Power supply unit / driver, or integrated electronics that convert line voltage to low voltage in order to run the LEDs. Sometimes The driver has electronics that can interpret control signals to dim LEDs. 

What are the different types of LED power supplies / drivers?

LEDs are driven by constant current (350mA, 700mA or 1A) drivers or constant voltage (10V, 12V or 24V) drivers.

Constant current drivers fix the current of the system and vary the voltage depending on the load of the LED.

Constant voltage drivers require a fixed voltage, and the LED loads are added in parallel across the output of the driver until maximum output currents are reached.

How do I know which type of driver is required by an LED product?


The LED rating of a product is usually noted in milliamps, mA or volts, V. Products rated in mA can be used with a constant current driver, while those rated in volts can be run with a constant voltage driver. LEDs designed for constant current drivers cannot run with constant voltage drivers without damaging them. 

What sort of applications are constant current drivers typically used for?


Constant current drivers are typically used in downlights where one, or a series, of luminaires is used per driver. These are connected in series.

What sort of applications are constant voltage drivers typically used in?


Constant voltage drivers are used in applications where the load is not known and the LED loads are connected in parallel, for example in coves and signage applications. These drivers are sometimes similar to the low voltage electronic and magnetic transformers used in halogen light fixtures (MR16 lamps). The type of LED driver suitable to run a LED product is stated by the LED manufacturer in the product specification.

What is the maximum permissible distance between an LED product and a remote driver?


The maximum permissible distance is dependent on the LED load, the conductor size, and the driver used. There is little practical limit on the distance between the driver and LED if you are using a constant current driver because it increases the output voltage to overcome any volt drop caused by the cable length. The distance between the LED and the driver is more important for constant voltage drivers where there is a voltage drop due to the load and length of cable.

What are the advantages of 24V LEDs over 12V LEDs?


LEDs driven by 24V drivers have longer permissible distances between light source and driver compared to 12V DC LEDs. 12V LEDs are usually suitable for applications where low light outputs are required. 24V LEDs offer products with higher outputs than 12V products.

Can mains voltage LED products be dimmed with traditional incandescent dimmers?


Although LED products are marked as compatible with traditional dimmers, there are various degrees to which LED products are compatible with incandescent dimmers. Compatibility needs to be checked and tested on a product by product basis for the following most common undesirable behaviors:

Reduced dimming range

Flickering of the lamp

Inconsistent performance based on the number and different types of LEDs connected to a single incandescent dimmer

What are the advantages of dimming LEDs?


Dimming LEDs offer the following advantages:

Saves energy, because less energy is used for reduced output levels.

Extends life; the electronic components run cooler. This not only extends the life of LEDs but also increases the life of the phosphor coating that is used to produce white light.

Helps designers create ambient lighting presets to create mood settings.

Increases flexibility in usage of space. A brightly lit space for reading or an office space can turn into a presentation/conference area by dimming.

Increases productivity by enabling individual control of lights in order to reduce eye strain and fatigue, or to improve concentration.

What are the various control protocols that can be used for dimming LEDs?


LEDs are controlled directly by signals coming from the central dimmer. They can also be designed to interpret other protocols like 1-10V, DMX, Ethernet or ZigBee signals from the central dimming system. The manufacturers of LEDs will specify which of the various protocols their devices can understand.

Why do some LEDs flicker when dimmed or turned off?


This is usually due to incompatibility between the driver and the control system. When purchasing an LED product, it is important to use the correct driver type as specified by the manufacturer. It is also important to check that the LED is dimmable. Some retrofits are not.

What precautions are to be taken when mounting LED drivers?


LED drivers need to be mounted in a ventilated space. Access to the driver needs to be provided for general maintenance purposes. The IP (ingress protection) rating of the driver needs to be considered before finalizing the mounting location of the driver (only those drivers designed for outdoor environments can be located outdoors). The distance between the driver and the light source needs to be taken into consideration in order to prevent voltage drop, which results in reduced output of the LEDs.

LED Light Housing/Fittings

How is light produced in an LED?


Light emitting diodes produce light by the movement of electrons between the two terminals of diode, which occur by a process called electroluminescence. When a light emitting diode is electrically connected, electrons start moving at the junction of the N-type and P-type semiconductors within the diode. When there is a jump over of electrons at the p-n junction, the electron loses a portion of its energy. In regular diodes this energy loss is in the form of heat. However, in LEDs the specific type of N and P conductors produce photons (light) instead of heat. The amount of energy lost defines the color of light produced. 

Why is the heat sink design critical for the performance of an LED fitting?

Heat management is critical for the performance of LEDs. Increasing heat in LEDs has the following effects in performance characters:

What heat transfer techniques are used to cool LEDs?


LEDs are cooled either by passive cooling or active cooling. Passive cooling involves a finned heat exchange system made of cast or extruded metal or a plastic coated metal heat sink that offers a totally silent, robust, heat transfer. Passive cooling is reliant on the surface area of the heat sink material and is orientation dependent. Active cooling may include conventional fans or diaphragm- based forced air cooling. Active cooling using a fan, although more efficient, is noisy, not so reliable, and requires electricity to run. Active cooling places emphasis on forced air flow rate and is not orientation dependent.

What is the two-phase heat exchange technique of cooling LEDs?


The two-phase heat technique is a cooling technique that uses the advantages of both active and passive cooling methods.

It works on the principle of evaporation and condensation. The process requires disposable heat to initiate the process that happens in a hermitically sealed tube that is filled with a minute quantity of liquid. The system has cooling fins around the tube to dissipate heat. This system offers high reliability, zero operation costs and is not orientation dependent.

What is junction temperature?


Junction temperature is the LED’s active region; the point at which the diode connects to the base. This is where the electrons jump between the two semiconductors to produce photons. A low junction temperature helps LEDs to produce more light also reduces lumen depreciation. Junction temperature is affected by the driver current, the thermal path, and the ambient temperature.

What are the different types of optical systems for LEDs?


The following are types of optical systems of LEDs:

Why are lenses preferred over reflectors for many LED luminaires?


LEDs are directional sources of light as opposed to the traditional luminaires, which are omni-directional. When LEDs are fitted with reflectors, much of the light at the center of the beam passes out of the system without even touching the reflector. This reduces the scope of modulation of the beam of light and can cause of glare. Lenses, however, help guide virtually every ray of light emitted by the LED.

What are the different ways in which luminaire design can help reduce glare from LEDs?

Here are few of the ways in which glare can be reduced from LEDs:

What are the common challenges or problems that occur when using LED fixtures in harsh environments?

What are the various causes of condensation within LED luminaires?


What product features should I look for when seeking LEDs for use in harsh environments?


Is it true that LEDs do not produce heat?


No. It is true that there is no heat, IR, in the beam. However, the LED fixture itself, does produce heat. However it may become warm, or hot, to the touch.

The LED luminaire is hot to touch. Why is this?


The LED chip, or light engine produces heat. This needs to be dissipated as quickly as possible. This is normally done by with a heat sink, which often has fins. Cool LEDs are more efficient than hot ones. They also have a longer life. Of course, higher power LEDs generally run hotter than low power ones because of the extra heat to remove.

Dimming lighting fixtures with controllers

What is ZigBee?


Zigbee is a technology developed by a global alliance of companies to create wireless solutions for energy management. These solutions which include a new open standard fo LED lighting controls. 

Retrofit Lamps--Replacing an existing traditional lamp with new LEDs

Are all retrofits main voltage?


Most retrofits have the appearance of a conventional lamp and are used as direct replacement for the existing one. i.e. they have a screw or bayonet cap base. With downlights and spotlights, it's common to have a 50mm dia reflector lamp. The mains voltage ones are usually called GU10, which refers to the flattened pins on the base. However, some are available for 12V supply fed from a transformer, e.g. Direct replacements for 50mm dichroic LV downlights. These will have thinner pins and are often called MR16 or GU5.3 lamps.

Are retrofit lamps all the same size?


No. You should check that the replacement unit will fit the luminaire. Many have slightly different dimensions from the lamp they are replacing. It may be necessary to get a sample of the retrofit lamp to ensure it fits your particular light fitting.

Will the light output be the same?


As with complete LED luminaires, it is important to ask the supplier for the lumen output and to compare this with the unit you are replacing. If it is a spotlight, compare the two lamps side by side. Poor quality sales literature often states the output from the LED chip and not the complete lamp.

Some retrofits appear a bit Cool, why is this?


Retrofit lamps are offered with various white light outputs, ranging from warm to cool. This is often indicated on the packaging. Typically, it might say “2700K Warm White” or “4000K Cool White”. The bigger the number, the Cooler is the appearance.

What could be a possible hazard when retrofitting lamps in existing installations?


Overheating of LED lamps in retrofit scenarios could be a potential fire hazard. Overheating can cause damage to lamp sockets, circuitry and lamps, and in extreme circumstances, it can even melt fixtures and floor coverings.

Can I put a retrofit in an enclosed or sealed luminaire?


The general answer is NO. The electronics in the retrofit will overheat and lead to a short lifecycle. A better solution is to use an LED module with a remote driver.

Can linear LEDs be used as a substitute for T8 or T5 fluorescent lamps?


Most LED tubes, although they have the same size, lamp base as a linear fluorescent, and possibly a similar lumen output, do not have the same omni directional light distribution. Many luminaires emit 20%-30% less light output with narrower beam spreads when fitted with LEDs. This is especially true of troffers with reflectors that offer batwing (wide-spread) light distribution with fluorescents. This needs to be taken into account when considering the overall 30-50% less power usage by LEDs with increased system efficiencies.

It is likely that the luminaire will need some rewiring and this should be done in conformance with the local electrical installation standards.

How to order led lights from SuperLED company ?

Bulk orders for Wholesale LED Lights & Lamps


Our warehouse often prepares most of the lamp raw materials, which can be delivered within 7-10 days after you place an order. If the number of orders is huge, the required material preparation time and production time will be extended accordingly, up to 30 working days. Please contact our sales team or WhatsApp: +86-137-1524-7959 for Offers/Quotation, including Specifications, Pictures, Price sheet, Trade terms and Delivery time etc, thank you!

Sample & end-user orders for Retail LED Lights & Lamps


You can place the order from our online lighting store directly, once we received your orders, shipment will be arranged within 3days. Please kindly click 

Regular shipping metholds of LED Lights from SuperLED to clients

Shipped by Sea


Ocean freight forwarders can be designated by customers or arranged by SuperLED company. If the ordered quantity of lamps is large, the containers will be loaded in our factory. If the quantity of lamps is not large, we will send your lamps to the designated marine warehouse for LCL. The regular delivery mode by sea is port to port. In fact, after the goods arrive at the port, you can contact the freight forwarder to deliver the goods directly to your warehouse.

Shipped by Air-transportation 


The regular delivery mode by air-transportation is from airport to airport. 

Shipped by International Courier


The most popular international courier for LED Lighting shipment available for choice: DHL, UPS, FedEx,TNT, Aramex, EMS, SF International. 

LED Lighting Failure Modes and Methods for Analysis 

Warranty, After sales and Maintenance of LED Light fittings

Industrial standards of LED Lighting fixtures

Technical FAQs

What does SMD mean?


SMD means surface mounted diode. This is a better technology than the first generation DIP LEDs. The SMD type LEDs are mounted on an aluminum substrate and enveloped in an epoxy resin.

What are the advantages of SMD over DIP LEDs?

The advantages of SMD over DIP LEDs are:

What are the various types of LED chip packages available in the market?


The basic types of chip LEDs are:

What are the typical types of LED modules available in the market?

LED modules may be available in the following forms:

Which developments in LEDs have reduced the number of components in a system?


The chip on board (COB) package enables mounting of the package directly onto a heat sink instead of relying on a LED board manufacturer.

In many designs the heat sink is designed to be a part of the luminaire housing design, which reduces the number of components in the system.

The development of more stable mains voltage AC LED drivers is leading to solutions that can reduce wiring requirements and overall dimming cost.

Our Sales Team

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