Joule Thief

[jadaro2600]

At all

I am  trying to   make  the  version of the JT that does not  have  a resistor .
I have  the  schematic   but  I have not been able to make it work.

Can  anyone  give any tips .......or even  an idea of how  far back  to to  try to find more on it ?

Is the  orange part  required?   


Thanks

gary

This is a picture I created; the colored parts are all optional points where voltage can be derived.

Here is a picture of a JTC running without a resistor, and instead a capacitor.  In the drawing you reposted, the capacitor can either be as shown, or instead linked to the positive terminal.  If you look at the pictures, you can see there is no resisted path to base, there is only a virtual circuit there where induction or flyback opens the transistor.

This type of circuit is hard to control when it comes to frequency, however, it will reach reach resonance, and it can then be tuned by adjusting the capacitor's capacitance instead.

( there is a delta to this of course, the circuit will only work within a certain range )
*edits:

I apologize for the mess, but I used different transistor in these pictures, it didn't seem to matter which one, the both worked, the little one is a 2n2222 and the big one is an NTE210.

Coils for the base and collector are turned side by side..in this instance, they are a twisted pair, and the pickup coil is 3 winds to one wind of twisted pair ( hence the notation in the schematic )  ..i have gotten this to work in other ways, however, this is the best example.

Also, the third picture is an axially molded inductor, with an inductor around it. This circuit runs at high frequency, the axially molded inductor contains magnetic materials ( ferrite ) and looks like a resistor.  This circuit also does not use a resistor.

( I guess these were the last experiments I did with this circuit before finals started )

[gadgetmall]

@gadget

Before undoing every thing try putting a bifillar coil in the basic jt way starting and ending at the same spot the pickup coil does .

Connect it to the jt circuit ( make sure to use a 2n2222 or 2n3409 so i could get a idea , resistor should be under 1k)if you cant get more then 30 volts then its a bad toroid.

Hi . Same results BUT i took an identical toroid and would 11 turn Bi Normal jt without all the 150 turns and it lights bright from 5 ohms to 100 k SO i wound on the other side 15 turns secondary put a diode and 104 cap on it . 39 volts . I would the secondary opposite ccw . so i added another 20 turns  59 volts .. This is with 2n3904 . Ok now i see . the secondary HAS to be opposite wound i think . Now i will try the same setup winding the secondary the same way as the bifialiar 11 turns and see what the results are . I am pretty sure i can keep wrapping wire on the secondary and increase the volts now . this is the highest i have see so far with these toroids with so little windings .what you think mark  ?

Gadget 

[gadgetmall]

Here is what I will try today.

I had a very 3D morning thinking about how the MK designs work and the one yesterday didn't.
(The part that was so amazing to me was that it was able to stop the working of the primary, because the basic joule thief light stopped working.)
I realize that the MK is basically a center tapped secondary.

The first winding is A the second down direction is B but when it crosses the centerline and continues in the same direction BUT is on the opposite side, it is effectively the same as turning the turning direction and therefore the pulse direction around. So when the second side of B is finished and you come back to the center you are winding in the A direction, but since it is on the opposite side it is also effectively opposite to the original A winding. You can have as many turns as you planned and they are all wound in the opposite way from the ones they are adjacent to, but they are just like one wound with a center tap.

This should mean that if I take yesterdays thing half way out, then make a 1/2 turn and continue to the end. each wire will be operating in the opposite direction on each half of the toroid and it should do everything it is supposed to do.

I don't really expect too many people to follow this. I am very spatial and I can see it, but maybe someone else can. (So, I offer it here.)

I will let you know.

And have a look at the center point of this baby (opposite the colored primary wires) . does it not seem to be making some small change here? I don't know.

It may take another 2 hours, but if it works, it will give another option for winding to us.

@stprue,
I was thinking it might not be a short on yours either. So, there is no verdict yet.

jeanna

Jeanna out of the three hazen reps did you ever wind the secondary opposite from primary's ? I think this is the problem . I did a test winding an 11 turn bi jt on one side and then another 15 in the opposite direction . I get a Good Higher voltage now . I tried the same 11 turns on top of th e150 hazen and still get 10 volts and hard to control so its is killing the core somehow .
with 11 on a blank toroid its perfectly tuned . now i am going to add 80 on the other side and try not to overlap and see if when i do over lap it goes down or not .

Gadget

Gadget

[TheNOP]

If  you have some shellack or something  similar   you could dip your toroid in that .

As I undersand it   the people that used to clean large motors for a living   cleaned out  the  windings  then  dipped   them in shellack just  to be sure that  they  did not have  a problem when  the motor  was  started  again  .

They probably  have  a newer  product  for that kind of stuff now.

they dip the coil of motors and transformer in "shellac"(resin or similar stuff) to minimize Mechanical losses and/or Stray losses.
for re-inforcing the insulation too, but it is a protection against temperature then for re-insulating the wires.

you would make a better job if you were to dip your wires in the resin and let them dry before winding your coils.
you will never be sure you have properly re-insulated your wires perfectly othewise.

[Mk1]

@gadget

Are you sure the toroid is the same one from goldmine ?
I know it is a decent one .

The diode used are also really important in testing , i like the 1n4007 because there good up to 1000 volts and i made test and compare different
bridges , and get huge difference in voltage like over 50 , the 4007 don't drop it much , they are not germanium but real good .

Have you use the page 478 guide.

Using that method i can quickly determine , the quality of toroid a good one i usually get 70 to 100 volt dc(rectified) at 1k.

Ok some idea for you , now that you have almost stopped the battery draw, why not go one more step , the base coil resonance is good but if both the coil are in resonance , noting should slip away .

The pickup coil can easily power other transistor, the tricycle is a good proof of that , i plan now on setting it in a endless amplifier way .

Have you tried the collector coil resonance ?

Mark