Joule Thief

[innovation_station]

i have a spec sheet some where for the core i used ...


5 turns .. was tuneing for the 140mm  i will post a pic when i find it .. 

w

[Mk1]

This is a repost from page 478 .

@all

I hope this will help !

First thing tuning, on step one the green coil is put on tight leaving room so that two other coil (for the jt)can be added 180 degrees
apart, the green coil needs to be connected to a diode bridge to get voltage readings .

On step 2 , you start adding jt coils one at a time and check voltmeter every time you put more turns , that way you see the difference it makes continue adding turns until the voltage on the voltmeter start going lower, this will mean you have reached the point where you start messing up with the turn ratio , meaning you add more you get lower voltage.

On more step i do is every time i change the jt numbers of turn i also tune the base resistor , usually a pot of 1k is used, you try to get the highest voltage on the voltmeter . i also keep the voltage data and the resistance at the base by checking the resistance used by the pot in the circuit.

At this point you will know that you have the right number of turns on the jt coil, and the green coil number of turns fitting in the toroid,.

At that point based on results decide to use smaller gauge the get more turns and higher voltage .

You will also have a good idea on the toroid working range.

To make a good design , you need to learn about the toroid first at this point you should have a good idea about doing so.


Step 3 , Start putting pickup coil on the toroid, you need to put the coil on both sides going one way and leave wire to come back over the coil the other way on step 4.Making a cross windings.

If you want more pickup coil , you need to put them all at the same time , so make sure to remember the green coil for the room available  .

Lets say 20 turns fit , then on a mk1 you should have about 20 up then 16 down , mk2 having 2 pickup coils on each side numbers would be 10 up 6 down , you get the idea.

When you need more then 3 pickup coil , twist all those wire into a single one then do it all at once.

Now why the cross windings , you will then have the coil pushing and pulling , you can test it with a led that will now light both ways , it also helpful in charging caps.

I hope did not forget to much, i would really make a video but , i really don't have any money to buy a camera
, and none of my friends have one, but honestly most of my time and energy is on putting food in my stomach.

Mark

How to test dead spots use a single turn pickup coil , then connect it to a bridge and voltmeter and move it around the empty space left on the toroid , if you find a spot where there is no voltage that is a dead spot.

Edit  ist made one watch http://www.youtube.com/user/innovationstation#p/u/22/Jiodkjo9hpk

[broli]

Thanks Mk1 that will be helpfull.

Btw I just hooked the LED across the transistor and it was brighter, I got too excited and added a 1.5V battery in series. It gave a bright flash and my only LED died  .

[gadgetmall]

Hi everybody,

@Ist,
Is magnetics the company you found and ordered from the other day?

I actually think we did have something to do with this. When lidmotor "published" allelectronics on youtube  as where I got the biggo I was glad I had bought more than one.
It did come from magnetics, but there is no info that came with it.

@Bill and all
I cannot follow the reasoning with any of that formula so I will wrap mine with 8 turns and let you know what I find out, as that will be the 'A' value.
or
Maybe an email to allelectronics will answer the specs question.?? ?? I hope.

I do not think the 3.38 inches is the necessary part.
I know the voltage does not need to be 985v!!
It only needs to be above 450v,
and  I got 411v with a one inch toroid this summer and lit a 4w 4" tube.
So, please no despair ...yet.

I think most of the effect has to do with the better transistor.
I just got home and I will be doing some tests on different toroids with this transistor, and the tip31 which both xee2 and stprue have used to make high voltage circuits.
So, I will report.
EVERYTHING seems to be closed now, anyway. No shipping til monday, my bank's computer has been down for 3 days so no money ... All I can do now is play.

jeanna

edit
@Gadget,
This is great!!
Please tell me some kind of catalogue number so I can cross reference.

thank you,

jeanna

here are the coated  toroids from magnetic . you cave to convert mm to inches http://www.mag-inc.com/products/ferrite_cores/toroids

[Mk1]

@all

I also know this now ...

What could i have new to say ?

Nut much , but if i was to try this i would first try to find the best gauge for the jt side (bigger wire ) then try the match them gram for gram , since they will have the same mass and materiel they will share resonance at any freq.

The smaller you go on the secondary side , bigger resistance higher turn ratio for mass , same mass smaller gauge .

I think this will make sure that the current is not lost due to unmatched weight ...

Depending on the winding direction you get different sine wave .

Winding rotation direction , can help setting kick generation (+or-), when working with multiple core.

I hope this will help

Mark