What is a LED?
Answer: 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.
How does LED work?
Answer: they don't have a filament that will burn out, and they don't get especially hot. They are illuminated solely by the movement of electrons in a semiconductor material, and they last just as long as a standard transistor.
Can LEDs be used to replace conventional incandescent and florescent light bulbs?
Answer: LEDs have been used in many different applications to replace old incandescent light bulbs, firstly in the fields of LED indicator lights for all kinds of electronic devices such as cell phone, calculators, automotive dash panel, LED flashing lights, and so on. Now as the developent of brightness of LEDs, they can be used to replace incandescent and florescent light bulbs for general lighting purpose.
What's LEDs' advantage?
Answer: High energy efficient, low heat generation, energy-saving, long life span, evironmentally friendly, fast switch time. For more details, pls check why use LED.
Is there any disadvantages LEDs exhibit?
Answer: Yes, LEDs is limited to light for its brightness. In the recently years, the brightness is strengthened much. They are 1W, 3W, 5W LEDs now. If a Cree LED Cool White 3W, it will emit 110-145Lumens while 1W will emit 70-85Lumens. As its development, we believe that brightness won't be a barrier for LEDs.
What types of LEDs do you use?
Answer: For the High Power LED Light Bulbs, we always use the Cree, Luxeon and Edison. And now we are thinking about the Samsung's. They are always chose by our customers.
Can we learn more about the Cree, Luxeon and Edison LEDs?
Answer: Sure, you can. Please browse the informations as folowing table.
Hight Intensity LED information.xls
Can LEDs be made in both Spot light bulbs and flood light bulbs ?
Answer: Actually, the beam angles of high power LEDs we used are 140degree and 120degree. To collect the light, we use a lens to change its beam angle to a narrower one. Then it shows us it is a spot light bulb. Nowadays, we are inquired by some of our customers that they want the bulbs in a wide angle, then we are working on a high-power flood light bulb. We are thinking to change the lens to a cover who won't change the beam angle of LEDs itself.
Can LED light bulbs be dimmable?
Answer: Dimming doesn't work very well on LED's, as it degrades the lifetime of the LED itself, not from the actual dimming, but from the physical action of dimming it. ( Actually, this conception is the same with other lamps such as Halogen.) Its life will be cut down to 20percent if you dim it often. For the actual dimming, you can either step down the voltage, say from a 12V to a 9V, and that will dim the lights, or you can affix a dimmer to them, effectively doing the same thing. But pls note, to protect the bulb, try to leave it in a stable position, rather than allowing anyone to brighten or dim it often.
Why are LEDs of some colors are more expensive than LEDs of other colors?
Answer: 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.
Can a DC 12V light bulb connect to a traditional AC Driver directly?
Answer: Yes, it can, but the light will be a little dimmer than that appears when it connects to a DC driver. To solve this problem, we have an idea that connecting a frequency-lower between our 12V light bulbs and the AC driver. For details, pls check it at NEWs.
Question: How to get to know the brightness of a LED light bulb?
Answer: We measure the brightness by some values such as Luminous flux, Illuminance and Luminous Intensity.
Luminous flux, measured in lumen, is the quantity analogous to radiant power, but compensated to include the above effects, denoted by F.
Illuminance, measured in Lux, is the luminous flux (lumen) per unit area(m2), denoted by E. 1 lux = 1 lm/m
luminous intensity, measured in Candela, is the luminous flux (lumen) per steradian, also called one candela, abbreviated cd, denoted by I.
Luminous intensity, however, is flux per unit solid angle, not per unit area, and the luminous intensity of a source in a particular direction does not decrease with increasing distance. 1 cd = 1 lm/sr
We place the source at the center of an imaginary sphere of radius R. A small area A of the sphere subtends a solid angle Sr given by Sr =A±R. If the luminous flux passing through this area is F, we define the luminous intensity I in the direction of the area as I=F/Sr , sr = 2 ヰ (1 - cos(ヨ/2)) ,
where sr is the solid (3-D)angle in steradians, and ヨ is the beam angle.
E=I*D(distance)-2 E=F/A(area)
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