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Step 6Fit the array into the housing
Using the pliers, press the form down hard onto the LEDs. Using the electrical tape, wrap the array with electrical tape until it fits snugly in the flashlight. Press the tape down on the back of the array so that the array will fit correctly in the housing of the flashlight. Now's also a good time to test to see if the array lights up correctly.
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Nov 29, 2007. 4:49 PMac-dc
says:
The way this has been constructed, it could be nice to take some clear epoxy and entirely cover the back of the LEDs and round frame. This will more rigidly fix them in place but also waterproof the assembly. If a thermal epoxy were used instead of clear, it wouldn't look "as" nice but then the epoxy would help to cool the LEDs more by spreading heat away from the leads.
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Nov 29, 2007. 7:21 PMmark_gober
says:
Cool the LED's??? LED's have virtually no heat. They are drawing mere milliamps. (mine draw around 20ma) While I appreciate your attempt to improve the design, that suggestion was a bit off target.
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Nov 29, 2007. 7:40 PMac-dc
says:
Untrue, it is known fact that LEDs both reduce in light output at elevated temp and that they do get hot, because the die is tiny and encapsulated in a relatively poor heat conductor. I can assure you I have made lots of flashlights and when 10 LEDs have their leads short and soldered to a PCB as a 'sink, it does get quite warm, and this across a thermal gradient due to the thin metal leads away from the die (mostly the cathode). If you have a single LED soldered to a fairly beefy piece of wire, this can be effective enoough for a single LED, and at least in the design here it was suggested they ran at 20mA, being easier to keep under a threshold value than 30mA would be (which is closer to the actual spec of these LEDs). Note what I just wrote, since these LEDs are 100mW type and are running at only 20mA, they are not at 100mW, not producing the rated light output. I know this was not directly applicable to what you wrote but it was a good time to mention since it bears on a light output estimation.
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