Joule Thief

[angryScientist]

One way to make a resonating coil more efficient is to reduce the self capacity.

Self capacity will make a current show up on the other end of the coil that doesn't help in producing a magnetic field. Coils should be slow in letting the current through. The current should have to force it's way all the through each and every winding creating a magnetic field as it goes. It builds up momentum, so to speak, in the magnetic field. When you stop feeding the coil current the field gives you that kick on the tail end, it gives you back all the work you put in to building the field but it does it quicker than the time taken to build it.

Tesla said in his Colorado Springs Notes that reducing the self capacity of his coils was essential. He started winding his coils with a spacing between the the windings. Using wire with a thick insulation with a low dielectric constant would work also.

I read in an electrical engineering book for radio design that a spacing of at least half a wire width between turns and at least 1 and a half wire width spacing between the core and the turns was a good rule of thumb to reduce the self capacity.

(It makes me wonder when I see people building Tesla coils on youtube with the turns as close together as they can possibly be; did they not get that memo?)

[resonanceman]

One way to make a resonating coil more efficient is to reduce the self capacity.

Self capacity will make a current show up on the other end of the coil that doesn't help in producing a magnetic field. Coils should be slow in letting the current through. The current should have to force it's way all the through each and every winding creating a magnetic field as it goes. It builds up momentum, so to speak, in the magnetic field. When you stop feeding the coil current the field gives you that kick on the tail end, it gives you back all the work you put in to building the field but it does it quicker than the time taken to build it.

Tesla said in his Colorado Springs Notes that reducing the self capacity of his coils was essential. He started winding his coils with a spacing between the the windings. Using wire with a thick insulation with a low dielectric constant would work also.

I read in an electrical engineering book for radio design that a spacing of at least half a wire width between turns and at least 1 and a half wire width spacing between the core and the turns was a good rule of thumb to reduce the self capacity.

(It makes me wonder when I see people building Tesla coils on youtube with the turns as close together as they can possibly be; did they not get that memo?)

HHHHMMMMMmmmmm

I did not  get the memo.



thanks........now I understand why  my big air coils didn't work.

gary

[resonanceman]

  Do we really need the higher powered JT, or can they be made to work great at very low voltage.   I like the way they can light a 90 light leds panel with 2v.  But it's not how low a voltage they'll work at, but How much Light and output they can be made to produce.  It may be possible to have them selfrun, with 0 volt external input. 
                                   NZ

NZ

I  have never  got a small JT to self charge...... it seems like it takes  a good kick  to get it done.

Do I understand  that you have tried using  feedback on a JT but  have not  quite got to the point where the  battery voltage starts going up.?

If  you are close  .........reduce  the power.
JTs seem to be much more efficent  at low power levels.

gary

[crowclaw]

@ All, Excellent contributions put forward regarding the effects of resonance and the performance of tuned circuits etc. It is the unique characteristics of how these resonant circuits perform that ultimately decide the quality of the results that can be expected from the JT experiments. This thread in itself is rather special from the many contributors that have posted their ideas and circuits for all to share. As will always be the case in such a popular experimental topic, more interest and first time experimenters are joining in. The same questions pop up... how, what, and if I try, etc etc. Those of us that have already been there and done it are naturally only to willing to offer  advice and support. The main problem now is the amount of valuable advice, experimental data, diagrams and schematics- not to forget the many U-tube clips etc locked up in the many previous pages of this excellent topic; which shows no signs of ending. May be it's time to archive this information in such away that it can be easily referenced?. I've no idea what efforts it would take to do this. I know Bill  has a reference section of data and pic,s for his experiments, and most likely Jeanna
anyway...just a thought. Kind Regards   

[Pirate88179]

Crowclaw:

I agree and I did this very thing over a year ago.  I fully admit to not having been able to keep up with it but, most of the early circuits are here along with references to the page where they were posted so folks can read them in context.

http://www.overunity.com/index.php?topic=6942.0

If/when I get the time, I will try to catch it up.

Bill