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UtahNature has a few interesting emergency light project uses a few white LEDs to create an inexpensive light. We tried making an LED light array with 3 white LEDs, then 4 white LEDs, but when we wanted even more light, we used 15 white LEDs.” |
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June 23rd, 2006
Why did he put seperate resistors on each LED rather than doing them in series? Or at least
have 3 or 4 LEDs in series and have little series groups. That would be much more energy efficient.
June 23rd, 2006
Hi David,
Only thing I can think would be for survivability of the circuit given a failure. Although we all know how reliable LEDs are and with a life of 100,000 hours this might not be the biggest concern.
June 25th, 2006
How is this better than a regular flashlight?
June 25th, 2006
Might not be better, but it would be more fun to build rather than buy
June 26th, 2006
We did this in March 2001, back when white LEDs were fairly new and expensive. We used current limiting resistors on each LED to make sure we didn’t burn any of them out. Of course, we quickly learned that LEDs are relatively hardy and could be wired in series without harming them.
The price decrease for LEDs and LED flashlights in the past 5 years has been amazing although not entirely unexpected.
This is truly a case where the follies of the past come back and bite you.
January 9th, 2009
Why cant the ckt be made more efficient by a charge pump ckt to drive the led chains off a low 4.5v battery that a flashlight has? can someone give a ckt idea for this?
I belive that the battery life will be much more that this. also the LEDs will glow more brighter.
April 9th, 2010
Alan pls can u reupload the construction of the emergency light ?
i would like to do this for my high school project
collin
April 9th, 2010
Hi Colin,
Looks like the original post has either been removed or has been moved. It was not done my be so I have no control over that.
If you do find it at a new location please let me know so I can update the links.
April 10th, 2010
Hi Colin,
I just got an email from the creator of the project. The links have been fixed.