China LED lighting factory

2009年3月13日星期五

FAQs

How efficient are led bulbs compared to incandescent bulbs?
Most led light bulbs are four to five times as efficient as incandescent bulbs. In other words, they use only 20% to 25% as much electricity to produce the same amount of light. The newest generation of leds are eight to ten times as efficient as incandescent bulbs. We use these new leds in our MR16 3W Power LED Track Light Bulb. It uses only 3 watts to output as much as light as a 20-watt halogen!

How bright are led light bulbs?
Led bulbs available for standard fixtures vary in brightness from less than 50 lumens up to about 400 lumens. The brightest led bulbs for standard fixtures are the floodlights and spotlights. The brightest of these uses about 11 watts and produces light comparable to a 50-watt incandescent.

Are bulbs with more leds brighter than bulbs with less?
The number of leds is not the determining factor of bulb brightness. Different types of leds vary greatly in brightness. The wattage of a led bulb is a better indicator of the light output. The typical light output for the current generation of white leds is about 30 lumens per watt. However, the newest power leds from Cree are in a different category with output up to 65 lumens per watt. Just three of these big leds can output as much light as 100 or more common leds.

How does the brightness of led lighting compare to incandescent lighting?
Led light bulbs are much brighter than incandescent or halogen bulbs of the same wattage, but led bulbs are not available in high wattages. Thus, when replacing incandescent or halogen lamps with led lamps, more led lamps are often needed. For example, to replace one 65-watt incandescent floodlight you may need two 6-watt or 7-watt led floodlights. Although you have more bulbs you are still using 80% less electricity.Incandescent bulbs use about five times as much power to produce the same amount of light as led bulbs. At low power levels the difference is larger. At higher power the difference is somewhat smaller. Electrical power is measured in watts. For example, a led bulb consuming 3 watts might output light comparable to a 20-watt incandescent bulb, and a 6-watt led bulb might be comparable to 30-watt incandescent bulb. Our brightest led floodlamps use 11 to 12 watts and output light comparable to a 50-watt incandescent.

Which led bulb is comparable to a standard 60 watt light bulb?
Unfortunately, there are no led bulbs that can match the light output of a regular 60 watt incandescent bulb at this time. The brightest led bulbs are directional flood lights and spotlights. The brightest of these are comparable to 45-50 watt incandescent bulbs. Few non-directional led bulbs are brighter than a 25-30 watt incandescent.

What do "cool white" and "warm white" mean, and what is CCT?
The Color Correlated Temperature (CCT) is given in the description of each of our white led bulbs. The color (CCT) of our white bulbs ranges from a warm yellow (2700K) to a cool blue white (7000K). By comparison, a typical incandescent bulb has a CCT of 2800K. A typical halogen is a bit higher, maybe 3500K. Daylight white is 4500K and a cool white fluorescent is 6000K or more. The human eye adapts to background light so that even a daylight white bulb will look slightly blue in a room illuminated mainly with incandescent bulbs. Similarly, an incandescent bulb will look very yellow in midday sunlight.

Can led bulbs be used with dimmer controls?
We have not been able to find any LED bulbs that are made to work with dimmers. However, we recently found a bulb that does seem to work okay. Testing with an inexpensive dimmer switch designed for incandescent bulbs, our SP80B LED bulb is dimmable from 100% brightness down to about 25%. It is the only high power LED bulb we have found that dims smoothly.

What is the difference between a floodlight and a spotlight?
Led spotlights output a narrower beam of light, typically less than 30 degrees wide. Most of the light from a spotlight is concentrated onto a relatively small area producing a bright spot. Led floodlights output a wider beam of light, up to 160 degrees, so the light from a floodlight is spread out over a much larger area. Because the light is more concentrated, a spotlight will appear brighter than a floodlight but only within its narrower beam. A spotlight is more suited to illuminating objects and a floodlight is more suited to illuminating areas.

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