At 02:52 PM 12/17/2009, Brendan Gillatt wrote: >-----BEGIN PGP SIGNED MESSAGE----- >Hash: SHA1 > >Dwayne Reid wrote: > > Good day to all. > > > > I recently purchased a LED flashlight that runs from a single 1.5V > > "AA" cell. Upon disassembling it, I see a total of 3 electronic > > components: the LED, a 10uH axial inductor and a 3-legged to-92 > > device labelled "TX2115". > > > > I haven't yet tried to measure output current or efficiency but hope > > to do so soon. > > > > My Google search for "tx2115" turns up only one close hit: a Chinese > > site showing that part number and describing it as a Boost LED > > driver. But: the picture is for a 4-legged to-92 device, not 3-legged. > > > > Anyone have any idea where I might find a datasheet for this device > > and, better yet, where to purchase them from? > > > > Thanks! > > > > dwayne > > > >It might be a transistor instead. See >http://www.emanator.demon.co.uk/bigclive/joule.htm Hi there. I'm familiar with Big Clive's stuff and have indeed built a couple of his Joule Thief LED drivers. But: this is different. Other than the LED, there are exactly 2 other electronic components: a single-winding 10uH axial inductor and this device. In other words, much easier to build than the Joule Thief. FWIW - I have some thin magnet wire (#34 or so) that is actually comprised of 5 separate strands of much thinner wire. That's what I used to wind the inductors for my Joule Thief units - much, much easier to wind. 4 strands in parallel for the main inductor winding and 1 strand for the feedback winding. dwayne -- Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist