Joule Thief

[resonanceman]

Gary,
I found it. I did this back in june.
The first pic shows the led in the basic spot lighting (I think basic)
The next is a scopeshot off the secondary.
You can see a ring on the scope shot the peaks are both made up of rings.

My notes say (I assume off the secondary cuz I only ever do that)
3.63v with the bjtl
10.73v no light

then I removed the core.(I had made these non galvanic types on a bolt which was inside a straw, so I could remove the core.)
4.5v -- no core
Then since the wire in the pic makes this a step down I tried something YOU told me about and I stuck a spool of red mag wire around the bottom... just to the other coiled secondary. The volts were
35.9v -- no core.

I think this is pretty cool.

I didn't put in my notes how I connected the wires. I assume the end of one to the beginning of the other like a normal jt.

jeanna

Jeanna

Thanks for looking that up .

I am sure that I  would have remembered  that post if I had read it before.

after  reading it  and looking at the picture .....my thoughts  were .   I wonder  how  many coils like the red one you  tried  would  work before   the JT  was  choked by the load.    ...... physicly it looks like there  is room  for  at least  4 ......if you remove your original  secondry


I  have spent  the  last hour  replacing  a 3055  in my test  board.
I  added  a connector  block for the  ends of the  wires going to  the transistor .......so next time  I will  be able to  change it faster .

Now ......I can  look into adding  a bifilar  primary  on  one of my LMs


gary

[resonanceman]

@ Gary
Hello Gary, I took a look at this web site link you provided, it seems to have what you are looking for, and should be suitable.

The battery link does point to the pdf on the scope, but there is no reference to the battery as you pointed out.

Seems you could use this on a USB main PC and could use it on an older laptop, the screen resolution (pixels) 640 x ? is a bit on the largerish side but would display the waveform OK.

I like the idea it can be battery powered, as you could take it to the work in the garden, unlike me, I just ran some extension leads to my scope.
One thing lacking was a utility to "null out" 50Hz or 60Hz, but mabe scopes dont have this, but sound jockies can get these things to stop mains hum from being a problem. Hmm now you got me thinking.....

I like the idea of being able to record the data in a databank, and being able to display it on the PC screen, top idea that.

Give these people a email and ask them to answer any questions you may still have, perhapse they could "software" some solutions also.


Anyway Gary, the final decision is yours, and price can be the key in many instrument purchases.

jim

Jim

Thanks  for  taking the  time  to look  at that scope.

It is  really nice to get  the opinion of  someone that  knows  about  these kinds of  things .

I am still kind  of guessing at what I need.

I guess a question  I should  have asked in my  previous  post   is   am I on the right  track  with my prioritys  for the scope?

I remember Jeanna  saying her  scope is  fast enough for her JTs
I do think that  faster is  better though.



I  like the  idea of  being able to use it with a battery too ......but  I  do not like their  choice of  battery .   L ion     If  I  remember right .......those kinds  of batterys  are worthless in 4 years  no matter  what you  do with them .    Even sitting on  a shelf  they  die .

Thanks  again for the help
I still have  some reasearch to do ........but maybe in a month or so I will  have a scope



gary

[jeanna]

.....my thoughts  were .   I wonder  how  many coils like the red one you  tried  would  work before   the JT  was  choked by the load.    ...... physicly it looks like there  is room  for  at least  4 ......if you remove your original  secondry

I think there is only room for 2... possibly 3.

Choked by the load of an empty spool?

I also think I did this before I fixed up a whole spool.
It may have been the inspiration for the whole spool, though.
I didn't write anything about it in my notes, and that is the reason I think it is the partial one I just picked up and tried.
This means there would be a LOT more volts from a full one.
I think a lot more before it is choked.

I do not have a figure for the red secondary with a core.
I am sure it is more.

I  have spent  the  last hour  replacing  a 3055  in my test  board.

I am glad to know I am not the only person who has to fiddle with those.

On the subject of the 3055... I am wondering if it is the quantity of silicon that makes the difference between it and the little switching transistors.
They both switch fast, but with the 3055 I can expect 100 volts more than the 3904.
The only thing that can make that happen in this flyback world is speed and sharpness of speed of switching.
The little lightweight 3904 may switch more but perhaps it doesn't switch as sharply, and I wonder if that is because it lacks enough + and o's to make a clean break.

Just a thought.

jeanna

[resonanceman]

I think there is only room for 2... possibly 3.

Choked by the load of an empty spool?

I also think I did this before I fixed up a whole spool.
It may have been the inspiration for the whole spool, though.
I didn't write anything about it in my notes, and that is the reason I think it is the partial one I just picked up and tried.
This means there would be a LOT more volts from a full one.
I think a lot more before it is choked.

Jeanna

I guess  I didn't  explain  it very well .

Here is what  I was  thinking of .

Then since the wire in the pic makes this a step down I tried something YOU told me about and I stuck a spool of red mag wire around the bottom... just to the other coiled secondary. The volts were
35.9v -- no core.

if you got  35 V with one spool  of wire .....  if you took off  your  original  secondary  and  placed  3 or 4 spools of wire  on the  coil just like the  first  red one ...... you might have  pretty good output .

On the subject of the 3055... I am wondering if it is the quantity of silicon that makes the difference between it and the little switching transistors.
They both switch fast, but with the 3055 I can expect 100 volts more than the 3904.
The only thing that can make that happen in this flyback world is speed and sharpness of speed of switching.
The little lightweight 3904 may switch more but perhaps it doesn't switch as sharply, and I wonder if that is because it lacks enough + and o's to make a clean break.

Just a thought.

jeanna

The  way I see it  .

If you have 2  doors  that open at the same speed .........but  one of them is 10 times  bigger than the other .....  you can move what every  you want to move through  the large  door  sooner than you can  get it though the smaller  door .


gary

[resonanceman]

First  tests  of  a bifilar primary added to a LM are  not the most promising

I added  400 inches of  #24 floral wire  coated  with shellac just to make sure it was  insulated .    and  200 inches  of #22 mag wire

I wound the  2 wires together  around the  LM .
When I got to the end of the mag wire  I just  kept  the end separate .
I kept  winding the  iron wire  giving me  more  core outside the other JT primary .

I have not tried to tune it  yet .     I just guessed at  a length of wire to start with .
It would not light  a LED in the original  JT position  with 1 AA but it lit with 2 AAs

This might  be a good  thing to check out  with higher voltages .
Also ......I am thinking if  a JY core needs to reach saturation ...... it may be possible to tune the power level by  changing the number of  iron wraps .


I kept  the  copper wire  shorter  and connected it to the base  because  I have noticed that  lower  resistance in the winding  going to the base seems to help .

Adding a core in the center  didn;t seem to change anything .

The LM that I used  is what I call a splitter .
It has 2 coils of the #22 Radio shack  wire wound on  one spool.
The idea  was to use that kind of coil to split the signal ......and send half  back to  the battery
I tried  several things  with it ...feedback didn;t help  the voltage .
then I  tried  a  small cap  it  has  221 printed on it .   
Would  that be  nF ?   
When  the   221 cap is  connected across  the SECOND  coil in the LM  the first coil  voltage jumped 3 V but my LED array roughly  doubled in brightness and the  JT LED got to bright to look at .

This is clearly  resonance   it is  a very narrow  band

Strange
I am using  a 10mm LED in the  JT position  it is very bright .
I was thinking it was using alot of power.
I disconnected it and the whole  circuit  crashed
The output  voltage  dropped from  37 V to less than 1 V
I could not get it to put out any power without the JT LED in place.


I  hope to try  a few more things tomorrow.


gary