Hein (fub) wrote,
Hein
fub

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LED Nightlight

With the new bed, and our new sleeping position, klik's end of the headboard doesn't have a convenient power socket nearby. We wanted to have some source of illumination there, so we decided to make a little night-light with 9 white LEDs, powered by two rechargable batteries.
The LEDs have a forward voltage drop of 3.2V (quite high!), so I can just hook 'em up directly to the batteries. However, rechargables have a maximum voltage of 1.2V, and at 2.4V, the LEDs just don't get that bright...

I had seen a voltage regulator circuit based on the LM317 somewhere, and I wondered whether it could be used to boost the voltage -- but alas, that is not the case.
But the LM2621 from National Semiconductor and the MAX1674 from Maxim can!
I've registered and ordered samples of both -- power supplies isn't my forte, but if I get this to work, I can suddenly create battery-operated stuff with relative ease as well!
Tags: electronics project
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