1. What is an LED?
A light emitting diode (LED) is a semiconductor device that emits visible light when electrical current passes through it, it is a special kind of diode.
2.What is the lifespan of LEDs?
Many manufacturers claim that their LEDs will last you 50,000 hours or even longer before operating at half brightness. But how valid is this claim?
Quite simply, the LED industry is not yet old enough to validate this figure. LED manufacturers perform numerous accelerated degradation tests, during which they both over heat and overdrive the LEDs until they expire.
From these results, they then extrapolate the figures to find the expected life span under normal conditions. From these tests, many manufacturers concluded the 50,000 hour figure. There are also many LED manufacturers who give an expected lifespan of anywhere from 30,000 to 40,000 hours.
A major factor in the longevity of LEDs is in the way that they are used - in the output. Different colours consume various amounts of energy, thus changing their total lifespan. Furthermore, the expected lifespan also assumes that the LEDs are operating at full brightness, which, depending on the application, may or may not be true.
We can see from the above that there is really no way to exactly confirm the LED lifespan of 50,000 hours. In reality, they may last much longer than this, or perhaps expire earlier. In any case, their lifespan is far longer than any other lighting technology currently available.
We have designed all LED lighting products to be under driven, ensuring that you will get maximum lifespan out of your products.
3. What are the advantages of LEDs compared with conventional incandescent lights?
There are several obvious advantages LEDs have over traditional incandescent light bulbs, they are as follows:
Low power consumption - energy saving,
Long lasting,
Cold lighting,
Ruggedness,
Small size and weight,
Fast switch times,
Simple to use.
4. Which applications I can use LED lights?
Architectural/ Commercial:
• Interior and exterior special effect lighting (eg. Hotel, restaurant, casino, water feature, landmark)
• Landscape lighting for gardens, parks, pools and spas
• Accent lighting
• Cove lighting
• Small spot lighting
• Path lights
• In-ground and underwater lights
Residential Applications:
• Decorative lights
• Pendant lights
• Under or inside cabinets
• Kitchen splash back lighting
• Recessed lighting
• Feature wall lighting
• Bedroom
• Bathroom
• Home theatre/ media room
• Entertainment Area
• Patio/ garden
Retail Display:
• Refrigerated display case lighting
• General merchandise lighting, eg, creating effects and moods based on warm/ cold colours
• Display case lighting
Entertainment:
• Concerts feature effect lighting
• Concert hall and theatre lighting
• TV Studios, stage lighting
• Bars, clubs and restaurant
Safety and Security:
• Exit / Entry Signs
• Emergency lighting
Outdoor Areas:
• Parking Lots
• Street and highway lights and signs
5. Could you give more detailed explanations about these LED advantages?
Yes. Currently available LEDs are more energy efficient than incandescent bulbs, but less than florescent bulbs with the same light output. The power consumption of popular LEDs ranges from 30mW to 200 mW.People can save money & energy by using LEDs instead of equivalent incandescent decorative bulbs. The rated average working life of LED is 100,000 hours compared with 1,000 hours of incandescent bulbs.
LEDs emit cold lights as working LEDs generate very small amount of heat, so LEDs are much safer than equivalent incandescent light bulbs in terms of danger of fire. LEDs don’t have filaments to heat up in order to emit lights just like the case of incandescent bulbs. Lights are emitted from LEDs as a result of energy exchange occurring in the different semiconductor materials an LED is made of.
LEDs are usually shielded with solid transparent plastic materials so they are more rugged than incandescent and florescent bulbs that are usually sealed with glass.
LEDs can be powered by either AC voltage or DC voltage. The circuit that is required to appropriately drive LEDs is much simpler than that for florescent bulbs.
6. We have seen so many advantages LEDs have over incandescent light and florescent bulbs, are there any disadvantages LEDs exhibit compared with incandescent or florescent bulbs?
Yes, the most significant disadvantage is the light output limitation of LED. Currently available LEDs emit limited amount of lights at a relatively small angle range, while incandescent and florescent light bulbs illuminate in all directions and give out much more brightness of light. And this is the reason why LEDs currently can not be used for general lighting applications.
The second significant disadvantage is the high prices of LEDs. The currently available LEDs in the market are 3 ~ 10 times more expensive than equivalent incandescent light bulbs. This is why some customers still hesitate to buy LED products even though LEDs have so many obvious advantages over incandescent bulbs and people actually can save money by using LED products in the long run.
7. What LED products are currently available for general customers?
The most popular LED products available in volume at the market place are various kinds of LED decoration light products. And in fact, they are ideal for replacing conventional incandescent decoration light products, because when compared with incandescent light products, these LED products save up to 95% energy, have much longer working hours, are more rugged, and safer in terms of danger of fire and electric shock.
At present, people can buy beautiful LED light strings, LED rope lights, LED icicle strings, and individual round LED bulbs with changeable colors, LED rope lights, LED pipe lights, and more other LED products will be put into market in the near future.
8. As we notice that in LED light strings, LEDs are in series connection just like incandescent light strings, how do you compare these two kinds of light strings in terms of reliability?
LEDs are more reliable. Most available LED light strings have series configuration like old incandescent light strings, where lights in the string are connected in series with each other, so a disconnection of LED light from the string will always make the entire string fail just like incandescent light strings. However, in the case of light burning, an incandescent light bulb will always burn open, namely, the filament of the incandescent bulb breaks, so the whole string will always fail, while an LED light may either burn open like an incandescent light bulb or burn short where a short circuit is formed inside the LED, so the burned LED will stop lighting but all the rest LEDs in the string still light normally. And LEDs usually burn short, therefore, LEDs are more reliable than incandescent light bulbs in that respect.
9. Are there any LED strings better than those in series connection?
Yes, there is. Various LED string products are more reliable than those LED strings in series connection in market. OUR strings use a unique patented connection configuration that ensures an LED string will work normally even one or several LEDs are disconnected from the string while keeping the low prices and all the features of LED strings.
10. Why are LEDs of some colors are more expensive than LEDs of other colors?
The reason is that different semiconductor materials are used for different color LEDs, and some semiconductor materials are more expensive than others; another reason is that manufacturing costs are different. White LEDs are the most expensive because red, green and blue LEDs are combined together to make a white LED.
11.Should I use LEDs with diffused, water clear, or color-transparent lens?
It depends on the application. Diffused lens contains diffusers which distributes the light output more evenly and makes wider viewing angle of a LED. Water clear lens, without diffusers, narrows the viewing angle, creates more focused beam, and increases intensity of a LED. Color-transparent lens has same effect as water clear lens. The purpose of tinting is to prevent mixture of different LEDs during mass production.
12.The intensity on your spec is measured at mcd (millicandela). How can I convert from mcd to lumens?
There is no direct conversion between the two units. Luminous Intensitymeasured in Candela or Millicandela is the light output in a particular direction. While Luminous Flux measured in Lumens is the total light output in all direction. Our factory can measure Luminous Flux (Lumens) with special requests, which takes about 1-2 weeks to finish.
13.Can LEDs be operated at AC voltage?
No, LEDs can only be operated at DC and require specific anode and cathode connection.
14. Can I Increase LED Brightness by Using Pulsed Operation?
Compared to DC operation, it is sometimes possible to significantly increase visible LED brightness by pulsing. There are 3 reasons why pulsing can increase brightness:
1) LEDs have more output at lower temperatures. Low duty factor pulsing can, in some cases, lower the operating temperature of the LED.
2) The human visual system is non-linear. With the right choice of duty factor and pulse rate, perception will correspond more to the peak brightness than to the average brightness. This is especially true at low pulse repetition rates. However, there are a couple of potential problems with using low rep rates:
a) Visible LEDs may appear to flicker, especially at frequencies below 30 Hz.
b) Flickering sources may be a hazard to epileptics. For more information, see the following sources:
3) Many LEDs have non-constant luminous efficiency. Luminous efficiency is the ratio of light output per milliamp of input. At very low and very high current levels, you get less light per milliamp than you do at intermediate currents. For an example of this phenomenon, see Figure 4 in the following Agilent (formerly HP) App Note:
From the above considerations, we can make the following generalizations:
a) If you are trying to operate visible LEDs at maximum possible brightness levels, you will always get better results using DC operation. This is because luminous efficiency declines at high currents.
b) If you are trying to achieve a compromise between battery life and LED output, i.e., you are not operating the LED at maximum power, pulsing is probably advantageous. If the LED datasheet does not provide an efficiency curve, you will have to experiment to find the best compromise.
What AATECH can offer you?
We specialize in Commercial lighting solutions; However,we are always happy to assist anyone who shares our passion and vision for LEDs.
For more questions, please email us at: info@aatechled.com, will reply you ASAP, thank you!