As featured in Trail-Friendly Radio in the February 2009 edition of WorldRadio on-line magazine, the Joule Thief is a handy LED-based device that can be used to illuminate your field operating position while getting the most out of AA and AAA batteries that have been pronounced "dead" by other electronic devices - such as digital cameras.
A hay-wired version of the Thief shows the simplicity of construction and the handful of parts needed to put it together.
(For a larger view, click on the photograph.)
The drawing below shows the Manhattan-style layout used to build the KI6SN Trail-Friendly Joule Thief.
(For a larger view, click on the drawing.)
Click here to see a Bre Pettis You Tube video showing how the circuit is assembled, including detailed instructions on how to wind the toroidal inductor.
3 comments:
Hello Richard, I built something similar from a circuit out of EDN magazine. The project was written up in the Spring 2007 ARCI QQ, I put it in an Altoids gum tin and get around 48 hours of operation running two high intensity white LEDs off a single AA battery.
73, Doug W7RDP
Just what is this circuit doing to up the voltage and decrease the current? Bob KI0G
Bob, here is a link to the EDN site for the version I built:
http://www.edn.com/contents/images/6413790.pdf
and here is a link to Dick Capples' site:
http://www.cappels.org/dproj/ledpage/leddrv.htm
better description than I could give.
73, Doug W7RDP
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