Joule Thief

[Pirate88179]

Quote from Jeanna:

"@Bill,

Yes, actually the first 2 are the ones I was thinking of. They are big and sharp and UNmodified makes it clearer exactly what to do. Hopefully folks who have not ID'd themselves here yet, will be able to make little bright units for rooms in their homes."

Just so you know, all of those photos are of modified boards.  It is just that the third photo has even more mods to it.  I just wanted to be clear in case some newer folks were looking in.  Of course, non of them have Gadgetmall's mods on them if that is what you meant. (I am still working on trying to figure it out)

@ Gadgetmall:

Feel free to mark up the photos any way you like to show your modifications if that suits you.  I know you have explained it, but, like Jeanna, I just don't see it yet.  Thanks.

BIll

[electricme]

@ all

OK some of you have been waiting for a while for this, but here it is, my BIG TORID JOULE THIEF.

I pulled my BIG Torid out of the cubboard, and wound my JT

I used the thickist wire I could find, put 7 turns on Bifilar.

Transistor is a 2n2222

Base Tr is a 1000 ohm 1/4 watt  Brown Black Red

LED is a Hi Bright one.

IT WORKS yippppee.

How big is this thing, take a look at the LM2912 transister I put on the top of the torid
The 2n2222 transister is dwarfed by it

Whats next? Going to put heeps of 2 turn secondaries on this thing and see what happens, ha ha.

Photo0831.jpg  = Whole JT on its hugely huge torid.
Photo0832.jpg  = Closeup view, showing the turns, big wires, 7 turn primary bifilar.

More to come in a little while

jim

[jeanna]

@all

Thank for all the positive feedback!

Think of this like a mk1 with 4 pickup coils , the positive of one coil set feeding the the other in perfect sync.

Mark

MK1,
I went to the butler site today. I think it is all very clear in my mind but then when I see a schematic like this I get twisted around. I get the concept, I believe.

I want to ask if you and I are thinking the ac is coming from the jt. I am pretty sure Butler is not saying that, but maybe they are. It just seems they keep on saying ac source.

My thinking is that the ac is right here in the joule thief and the next core is wound in a single direction and therefore is dc. The battery is feeding them both through a variable resistor, and when the tuning is right the saturation/unsaturation will make and break this just like a transistor, but without the problems inherent in the transistor.

Is this what you are thinking also?

Then the next thing to do is add the secondary and light the light.

All the research on core types and winding proportions and other details are being worked out by the whole group, and they are not yet ready, IMO. When these 2 parts come together we will really have a thing that can go anywhere and light those lights... Then on to cookers etc.

Is this the page you are on?

thank you,

jeanna

EDIT ADD:
Wow Jim, that toroid is really big. Drop it on a mouse!

See what you get from a single turn? then 2 then 3. please. (after that, you can drop it on the mouse.)  -j

[electricme]

@all
OK I removed the flimsy Red positive wire, soldered a switch to the Torid (+) turn, soldered a heavier Red wire from switch to the battery holder.

Next I unsoldered the 1K ohm resistor, then connected my new tool (Resistor Substitution Wheel) and cliped its leads (black and red clips) to where the resistor was.

Selected the 1k on the resistor wheel

Turned on the switch, and the LED glowed brightly.

Discovery time, this circuit works up to a resistance of 2.2k ohms
It also works down to a low of just 5 OHMs, but I think that is really tooooo much like a short so I took it back up to 1K ohms

The best resistor to use is between 1K ohms and 820 ohms

OHMS     RESULT Observed
         1 = 0 LED off
         5 = LED turns on          Tr gets hot
       10 = LED on                   Tr still hot
22 - 56  = LED on                  Tr warm to cool
up - 1k  = LED on                  Tr cool works OK
   2.2K  = LED goes very dim  Tr still OK
above   =  LED goes out


See pics

jim


pic 0383.jpg = Resistor Selection Wheel is connected to JT
pic 0386.jpg = 1 K ohm resistor is removed, Red and Black alloigator clips attatched to Tr1 and torrid bifilar junction.
pic 0385.jpg = RSW is set on 5 ohms setting

[Mk1]

@jeanna

I am not sure i get your question , but in the plan there are 6 coil on one toroid , 2 for the jt at 180 degrees and i 2 other coil on each side , like the mk1. The pair( one from each side are connected in series  (make sure there polarity match) then you rectify it (but a bit differently so you isolate the positive side of the ac wave ) and send it back in the second pair (you can adjust the feedback with a resistor )also connected in series then the output , could be rectified for dc or use as ac.

The mag amp can be used in many ways , this is a variation.

Mark