Joule Thief

[dog812]

Yes would you please share with me, as that is my main reason for making this ... RGB hula hoops are main seller.
http://ledhulahoop.com

@all
     Just for your Information . RGB leds will not work on a Jt normal or secondary  as it stands . . The reason why is they RGB leds Have a MicroChip in them and Malfunction on a Jt . . I have The cure ! I have Played with them and have ran them fine with a modification I have .Same goes for any Chipped Led  be it Blinking or rainbow RGB's 


Regards
GADGET 

Also... I think i may have bought the wrong transistor.. will a PN2222 Work? haha.

[jeanna]

Hi dog812,
(what a funny name!)

I don't know about the transistor, but if it is working in the bjt it is probably not the problem.

Maybe as gadget suggests you should put aside the rgb's for this testing period.

I am seeing a couple of things in your pic that have caused me problems.

1- the bifilar part that you show is an advanced style not a basic style. Make one with the bifilat turns going all around so you end where you began. That is the basic.
2- the secondary turns are in the only place that could be a dead spot.
I asked MK1 about this because he found a dead spot in his. But again, that is a LATER design, not the basic joule thief.

3- I found that it is much better when I wrap the secondary first up then down as in all of MK1's designs.

I like MK1's designs, and yet at the moment, I still have a better result with the hybrid.

The Hybrid is made with 2 secondaries each one going up then down as in the MK1, but the bifilar basic jt part of the hybrid is 11 turns bifilar just like the very basic.

Tuning comes later. (some of them do better with fewer than 11 turns, but then there is the problem of placement etc.)

So, make 1 with 11 turns bifilar just like the evilmadscientist one, (prove the circuit with a led then remove it) , add secondary turns around the side -NOT opposite the end/beginning of the basic part.
Check for traces of varnish on your mag wire and touch the wire to the plain led.

Let me/us know how this beginning step does.

(My 29leds were all lit from one like this. Later I uploaded a pic of 30 using the MK1, but those basic ones really do work well.)

thank you,

jeanna

(did the dog eat a hula hoop too?  )

[TheNOP]

A good magnetic core material must have high permeability.
this increase the coefficient of coupling.
but be carefull, the permeability is generally a function of the frequency

that mean: find at what frequency your circuit will run then choose the proper core for it.
you can cheat by adding more turns, but it is not the proper way to get the most out of a transformer.

if your jt can't reach a high enough frequency, that is needed for your core to work at it maximum efficiency, you will see blind spot(s) on it.
because the coefficient of coupling will be low (less iron in it, more resistive).

a way to kinda solve this, is like jeanna sayed.
is to spread the coils all around the core.
you can have only 8 turns it does not really matter, just spread the turns all around the core


"Soft" iron  can create a field as much as 50,000 times more intense than with an air core.
but because iron is a relatively good conductor, it cannot be used in bulk form(solid form) with a rapidly changing field(frequency), as intense eddy currents will appear due to the magnetic field, resulting in huge losses (this is used in induction heating).

that mean that the more a core material is a good conductor, the more intense eddy currents will be.
is not copper more conductive ? 
copper act as an air core witch is best at higher frequencies and at low frequencies it not good because there is almost no coupling at all.
and the higher the frequency the more intense eddy currents will be...


lamination and powdered techniques help greatly in reducing eddy currents lost, so, there are no reason not to use iron or other high iron material as a core.

be aware of the hysteresis curve of the meterial you want to use tho.
as this is what limit the highest frequency you can use your core at.

hysteresis is the time it take for a material to change it magnetic poles(north to south/south to north)
if the frequency is higher then it take for a material to change it magnetic poles, you will loose efficiency by alots.

it is worth noting that the current frequencies the jt work at(from various reports of peoples having scope) is well inside iron's hysteresis curve.

[Mk1]

@theNop

What to you think of aluminum core. All good info there , but a bit technical for none ee .
Keep the good work , cant wait to see what you are up to.

Mark

[innovation_station]

FUNNY you mention this......   


i tryed to post a pic earlyer on today

yea i leave it there.... lol

sure ill get to posting it ... lol

my cores came today ...  they are GREAY 5.5" 

the pic i was gonna post ... ALUM  

ill try it now

lol

more than meets the !

ist!

but first this video!!!!

http://www.youtube.com/watch?v=BWyTxCsIXE4&feature=related