So to find watts we multiply 3.15 (forward voltage) by 2 A (2000mA = 2 Amps) which comes out to be 6.3 Watts. From Figure 8 you can see that at this drive current the forward voltage is 3.15. Say we are running this Cree XP-L at 2000mA. This helps give a better idea of the light to expect from an LED and if it will be as much as the old lighting. In Figure 7 we show different incandescent bulbs and how many Lumens they give output. LEDs have much better efficacy which makes it nearly impossible to measure in this way anymore as a 50 Watt LED will be significantly brighter than a 50 Watt Incandescent. This is due to the fact that light was always measured by the wattage of a bulb. It may be hard to find the LED and Lumen output needed when switching to LEDs. Taking the 460 lumens from above and multiplying it by 1.75 we can see that the cool white XP-L running at 2100mA gives off about 805 Lumens. Following the curve to 2100mA (?) we see that this is a 75% increase in light. The arrow is the tested (base) output (at 100% relative flux). current graph on the datasheet that looks like the graph to the right. When driving an in-between drive current that is not listed, find the relative flux vs. To the right of that are the typical Lumen numbers for 1500, 2000, and 3000mA drive currents.įor the sake of this example, say we want to run this LED with a 2100mA BuckBlock LED driver and we need to find what the light output would be like. The highlighted number is the typical flux 1050mA which is the current the XP-L is measured at. We will touch on binning later which is labeled in the ‘Group’ column, but let us assume we are going to use a cool white XP-L from the highest bin (v5). First, find the Flux Characteristics table (figure 5). In this example, we are using the Cree XP-L. Example: Finding brightness of Cree XP-L at 2100mA On all of our LED pages, we link to the manufacturer’s datasheet at the bottom of the page. To do so, information is needed from the datasheet of the LED. The above resource can always be used for determining the light output from an LED, but finding it manually is not very hard. Take note that these are measures for 1-Up stars so if you want more light the 3-Up LEDs are a good option as they are triple the light within the same footprint. We have done a lot of the groundwork here, in a post measuring the brightness of each high-power LED at different drive currents. Now comes the tricky part, selecting the LED and driver combination that will output the light needed. High-power LEDs can take currents from 350mA to 3000mA. LEDs vary on their current ratings so be sure to keep track of this when picking an LED and driver. Current is measured in milliamps (mA) or amps (A). The amount of light (Lumens) an LED emits depends on how much current is supplied. For 5mm LEDs, their viewing angle also affects the light output they give off, for more on that see here. Note that 5mm LEDs are usually listed in millicandelas (mcd). A Lumen is a scientific unit measuring luminous flux or the total amount of visible light from a source. Sometimes it is hard to tell how bright an LED will be because it is measured in Lumens. LEDs are not only known for their colors, they are also a lot brighter than other light sources. As far as colors go, we carry from 400-660nm. You can always find the color or wavelength of our LEDs on the sub-section of the product page and can even search by color from our LEDs dropdown menu on the homepage. We try to carry similar color temperatures and wavelengths for each brand and type of LED. The LuxStrip can house 6 LEDs per foot and is easily connected up to 10 feet long.įigure 4 – LED colors and color temperature All our high-power LED options can be built on a linear design as well. We also offer QuadPod’s which can hold 4 high-power LEDs on a board slightly larger than the 20mm stars (see Fig. The boards are insulated and contain conductive tracks for easy circuit connections. Our 20mm 1-Up and 3-Up starboard designs are the best sellers. 1) or are mounted to a Metal Core Printed Circuit Board (MCPCB). High Power LEDs come as bare emitters (as seen in Fig. Cree tends to have higher listed Lumen outputs and is a market leader in the High-Power LED sector. Luxeon, on the other hand, has excellent colors and thermal control. Some prefer one over the other but that comes with experience and knowing what to look for. We carry high-power Surface Mount LEDs from industry leaders Cree and Luxeon. Both are excellent in our opinion, that is why we carry them after all. Surface Mount LEDs are diode(s) that can be placed on a substrate (circuit board) with a silicon dome over the diode to protect it (see Fig.
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