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Forum Index : Electronics : XM-L LED
| Author | Message | ||||
| irishron40 Senior Member  Joined: 22/09/2014 Location: IrelandPosts: 251 |
hi i am a little confused, I have a XM-L LED out of a torch that uses 3 1.5v batteries. when i connect this XM-L LED thru a lm317 with output adjusted to 4,5 volt its not half as bright. this led draws 0.47A how can i solve this? thx |
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| isochronic Guru  Joined: 21/01/2012 Location: AustraliaPosts: 689 |
What voltages/current does the the 317 circuit have ie input and led ? I am guessing your 3x1.5 cells are powering the led up ok but the 317 is dropping out, it would need say 5.5 - 6v input for 4.5v output I think |
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| Pete Locke Senior Member Joined: 26/06/2013 Location: New ZealandPosts: 181 |
Here is the data sheet for the LED. Did the torch have a P.C board with clever bits on it with the torch? If so you would need to include it when powering it from any sort of supply, including batteries. There should at least be some sort of current limiting involved, as an LED is just like a zener diode when it conducts. |
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| irishron40 Senior Member Joined: 22/09/2014 Location: IrelandPosts: 251 |
thanks for that info . ron |
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| irishron40 Senior Member Joined: 22/09/2014 Location: IrelandPosts: 251 |
just found out the problem. The problem was that I had a bad earth. I had build a rotating lighthouse out of what ever parts I had. I had a shaft inside the rotating part and earth was taken with a brush from washing machine as it needed to be able to rotate. the shaft had a laquer on it which mad the contacts only maybe working at 50%. Mad a copper shaft and now its full beam. Just learned something elese due to this, thanks for the help ron |
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