Electronics > Beginners
Help identifying an LED and also an application question
TT_Vert:
The 747 will fly on 2 engines so you were still good. Now if you lost an engine in a P51 you'd be in for a ride. :-DD :-DD With that said, I did ask just that and told them I wasn't looking to buy in bulk. For the time being I used White T1 LEDS. It works fine but I'm going to wait until tonight to see if they'll be bright enough. Not the best way to do it but you can't really see this as it's recessed in the mirror. if someone has a source for BRIGHT cool white LEDS that are 1W or less I'd be interested. Or other possible solutions one w/ more experience has than myself. Sorry for the angle as it makes the LEDS not look center (they are), I didn't want to open the door and floor the camera w/ light.
Brumby:
--- Quote from: TT_Vert on January 25, 2019, 09:20:34 pm ---The 747 will fly on 2 engines so you were still good.
--- End quote ---
[trivia] I believe an empty 747 can fly and land on only 1 engine [/trivia]
Interesting package. I can't say I've ever seen that before ... but then I don't get out much.
TT_Vert:
From what I've read you cannot maintain altitude on one engine in a 747. It can help w/ the glide slope though :)
So can anyone recommend a fairly bright light hat would fit my needs here? I have confirmed the T1 does actually illuminate well but I'd like a hair brighter if possible. Even something that isn't so long so i can use more of the reflector to help w/ lighting. Maybe even round LEDS on a PCB w/ a metal round plate w/ wires to main pcb would work.
TT_Vert:
Just came up w/ a much better solution. Using some 1W 6500K replacement lights for my aquarium lighting I just reamed the holes a bit and did this. I'll use jumper wires from the pcb to these. These are much brighter also. Question, anyone know of an adhesive that is resistant enough to the head of these LEDS but is removable? I was almost thinking of using a dab or two of RTV. I have used it on turbo manifolds in lieu of gaskets so I know it's up to the task as far as heat goes.
Perhaps one of you can answer something about these LEDS I may potentially use. The specs are as follows "
--- Quote ---White
6000-6500k
3.4-3.6v
350ma
100-110LM
120
--- End quote ---
My question is that is says the forward voltage is between 3.4-3.6V but the current is 350mA. Isn't that extremely high for a white LED? Don't they usually draw around 20mA? Is this spec assuming some type of heat dissipation or the voltage it can support w/o active cooling? As of now I have the light powered at 2.70V and the back metal part of it is at 93deg F. I then increased it to 3.3V and 170mA were being drawn stabilizing at 151 deg. F. I just don't know what an acceptable temp is w/o any active cooling. Plus is's going to be in a plastic housing so I don't want to melt that. Not sure at what temp that plastic melts however.
Thanks
Dave
alsetalokin4017:
Well, those are "One Watt" rated LEDs, right? So how do you get to one watt, if you only draw 20 mA? Answer: You don't. You give them enough voltage so that they draw about 350 mA and that's probably going to be 3.5 volts or so.
Those LEDs are designed to be mounted on a heatsink, or at least a PCB with sufficient copper area to carry away the heat when they are fully powered at 350 mA.
Of course you can power them at lesser brightness with lesser current and have less heat to get rid of (as you have found out by giving them only 2.7V). But that's inefficient.
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