Joule Thief

[dasimpson]

well the clock just turned 22.29 and the test joule thief is still going strong
woohooooooo money cleard time for some 2n3904 and some more leds and maybe a bread board

[jadaro2600]

I'm wondering if anyone can remember the location of the diagram for the circuit ( in this thread ) with the unusually hooked up transistor - I think it was behind the inductors and not in front of it?

It was a black and white, with a few notes, it may have been smirkey that came up with it.

[kooler]

jadaro
is this the circuit you are looking for
this guy does a better demo than me so here is his video

http://www.youtube.com/watch?v=8lSIuMIqtHc

[jadaro2600]

jadaro
is this the circuit you are looking for
this guy does a better demo than me so here is his video

http://www.youtube.com/watch?v=8lSIuMIqtHc

I'll have a look - Your name is familiar, also.

- - - - -

I was just considering driving the JTC with a higher voltage source, two batteries instead of one.  If we're going to run it until it's as low as possible, then it may fatigue the batteries.  We probably shouldn't do this with rechargeable batteries, instead ..

If I have two batteries, and can drive the circuit down a minimum voltage of 0.65 or so without using germanium transistors; I can only drive one battery down to 0.65 ..if I use two, then each battery would discharge to around 0.375 ..and more current would be pulled from the source.

So, my considerations are for operating a mosfet in linear mode, I need a voltage controlled resistor or some rigging of a mosfet which scales predictably in ohmic mode.  Has anyone had any experience with rigging mosfets in this manner?

I would probably need a depletion mode, something that would slowly phase out it's resistance as the voltage dropped.  Such a setup would allow us to maintain a stable operation even with a range of voltage sources.  I thought it worthy to work on such a setup because the joule thief circuit seems to pull more current as the battery dies or when there is no load on the secondary, etc.  This essentially means the transistors go into runaway mode.

Lights would not dim, per se, just cease at some point, preferably at the threshold of the base-emitter saturation voltage.

[kooler]

jadaro
the circuit i made.. backwards jt .. at 3 volts it starts to give off alot of rf signals.. put a wire from the back of the capactor side and loop it around a tank circuit and it will run alot of leds..
or put a 9 volts on it and it will mess with radios 20 meters away..
all that with 5ma's and less..
if you want i will post you a circuit like it that lights 10 leds on the battery side with a double A battery or 35-40 leds with a 3volts
but keep in mind that on 9 volts it was messing with my pc.. so it can't be good for the person running it..
you can run air coil with this at low ma's.. or you can just make your cat go nuts..
but i give up on this circuit because it didn't catch to many peoples interest..
but if you build it and it works it will get your attention,,
good luck
oh i meant to say that (stprue) went alot farther than i did..
he does really good work
this is his video
http://www.youtube.com/watch?v=XfzD1vgphoA

robbie