Joule Thief

[Farmhand]

It should have been a simple set up as you say, I've modified the board picture to show orange input positive black negative and
Yellow output positive. That circuit drawing shows the pins in a mirror image to the data sheet and the part I think, not sure.

Did you have a load connected ? Maybe the 1402 part needs a constant load, on my 1401 board I put a 3 mm indicator LED with
a 1K resistor is series with it. A tiny load but it's something, not that the 1401 part needs a load and I don;t know if the 1402 part
needs one either.

Maybe the board or one of the parts was defective. If you can't see any reason for you ruining it (if it is ruined) then email them
and they might send you a new one "tested maybe".

..

[MarkE]

It should have been a simple set up as you say, I've modified the board picture to show orange input positive black negative and
Yellow output positive. That circuit drawing shows the pins in a mirror image to the data sheet and the part I think, not sure.

Did you have a load connected ? Maybe the 1402 part needs a constant load, on my 1401 board I put a 3 mm indicator LED with
a 1K resistor is series with it. A tiny load but it's something, not that the 1401 part needs a load and I don;t know if the 1402 part
needs one either.

Maybe the board or one of the parts was defective. If you can't see any reason for you ruining it (if it is ruined) then email them
and they might send you a new one "tested maybe".

..

That wiring is correct.  If things got hot I suspect you had the ground and 1.5V reversed.  The NCP1402 is probably dead.  The diode should be OK.

[Pirate88179]

Farmhand:

Thank you very much for your reply.  In my edit on my post after I had thought a bit about it, and now I see from your drawings, that I should have left one of the holes open, and used the common ground for the - of my led.  I did not do that.  (Why do they have two holes for the 3v out then?)  My load was a regular 5mm led so probably about 25mA's or thereabouts.  The circuit heated up no matter how I had the led leads in the two 3 v output holes.  I really appreciate your post so now, if I fried that chip I can replace it, or if the board is bad, I will get another to test, but at least I now know how it is supposed to be connected.  Thank you very much again Sir.

Bill

Mark:

No, my polarities on my input matches Farmhand's drawing.  I double checked to be sure as, you know, shit happens.  Maybe there is a short in the board or maybe having the diode (led) reversed caused this although I do not see how as it heated up either way I hooked up the led.  Or, possibly, like Farmhand asked, my single led load was far too small?  This chip is supposed to handle 200 mA's and I should have only been drawing 25 or so.  The led did not even flash or anything but, I will check to see if it is fried.  They usually have a very distinct smell when they fry.  (ask me how I know.. ha ha)

Thanks again fellows, I will keep you posted.

Bill

[Pirate88179]

Well, I wired up that tiny board this weekend and....it works!!!!!

Thank you Farmhand, I wired it as you suggested and everything is fine.  I guess whatever was wrong causing all of that heat did not fry anything.  (Amazing)
I went ahead and soldered everything instead of just sticking the wires in for a test, which probably caused a short somehow.

Running a single super bright 5mm LED and it is very, very (blinding) bright.  I can't really test it now but the amp draw should be about 25 mA's or thereabouts.  It will be cool to see how long, and how low this circuit will go.  I will just have to remember to leave the circuit on when it approaches .8 volts or it probably will not turn on again.  If this gets anywhere near .3 volts with a bit of light I will be totally thrilled.

Will keep you all posted.

Farmhand, thanks again for explaining the hook-up to me on this tiny board.

Bill

[drodenbe]

Hi every one!  I am a newbie to posting stuff but not to electronics.  I just wanted to share my findings I have been working on for several years and just recently was successful in a joule thief design that will run a LED brightly and charge the battery at same time.  I am currently running on a crystal battery I made and it too is a new design quite successful so far.  So I am posting my circuit and feel free to try if you want.  I also included the formula for the crystal battery if interested.  For more info on the battery go to the crystal battery forum under Fausto.  I have posted how to make it.  It is different than others.  So that being said,  here is the post.  I also included a jpg of the coils I am using although it works with standard joule thief cores.  It also works with air core as well.    Thanks.

David