On several dollar-store type lights I have seen them only use one AA battery, and a small circuit that contains one or two inductors and some other resistor/transistors to drive one LED. Does anyone have a basic schematic diagram of this?
Thanks for the help! I searched more on joule thief and I have found what I was looking for:
http://www.joulethief.com/kit.php
The other circuits use a hand-wound inductor, but that one above uses a normal inductor.
Cool! I didnt know they could drive that many LEDs.I had used the same circuit before and made some changes to where I can light 9 white LED's off of a single AAA battery, have not tested it to see how long one battery would last with 9 LED's but the circuit does work better than those hand wound inductor ones..... here is a video on youtube showing my initial power up test of the circuit >>> http://www.youtube.com/watch?v=6zVOcND-FuQ
My .02
I ended up using a 1000uf inductor and changed the 2.2 K to a 3.3K and used a .01 cap instead, and (when I first built the circuit I used all the same components, it could still light the 9 white LED's but they were a bit dim) after my alterations to the circuit (which wasn't much) all 9 lit up pretty bright! I have not tested it to see how long a AAA battery can sustain the circuit, but I have used the same circuit to boost my Solar LED lawn lights, and now I get a lot more than just 4 to 6 hours of light, and the lights seem much brighter than when I first purchased them....Cool! I didnt know they could drive that many LEDs.
So I built that circuit:
http://www.joulethief.com/images/boost-schematics.gif
I did not have a .001uF capacitor, so I used a .1uf cap. It still works. How does the capacitance value affect the circuit?
Also I did not have a 470uH inductor, so I used a 150uH. Still works. How does the inductance value affect the circuit?
Thanks!
by Duane Benson
by Jake Hertz
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by Jake Hertz