Joule Thief

[Mk1]

@Cap-Z-ro

I think it could Work but the pulse would have to be as strong or stronger than the magnet.

[amigo]

What bugs me here the most is nobody seems to be concerned with the input consumption. Everyone is rejoiced they can lit two or 300 LEDs, but at what expense?

I think the idea with JT is that you should be able to light LED(s) for a long time, implying a low current consumption from the battery. Further more with most of these designs there is a limit to which you can use the battery with the JT until you lose the functionality, LED will go off basically once voltage in the battery drops below certain level.

The point is if your JT uses 20-25mA of current then you might as well hook the LED directly to the battery source and not bother with anything because you are consuming the actual current LED needs to operate.

The best result seems to be around 45-50% duty cycle square wave oscillator. With shorter impulses the LED does not light up as bright, although the current consumption is < 5mA (depending on the circuit).

I think there should be some ground rules set here what the goals are. In my humble opinion some of those would be:

1. Usable light output.

2. Being able to connect more than one LED for greater light output.

3. Minimum current consumption/maximum battery source longevity.

and then the tall order one...

4. Feedback into the battery source for recovery of power.

Even though I am not a big fan of quantifying things, we need to start doing some measurements and see what the gains (if any are) of individual circuits. There should be a solid science behind this and a rational explanation of why. When I say solid science that means experimentation, repeatability, enforced with some theoretical background.

I did post a link to two ebooks earlier that most probably ignored. One was about LEDs, basically A-Z and the other about commercial power drive systems for LEDs. Both did appear to have interesting bits of info that could be used in our quest here.

[jeanna]

@MK!

Well well,

I just turned the led on my brand new breadboard joule thief and ... it lit right up. amazing. I am aying that alot. Sorry for the repetition. 

It is much less bright than the other way, however.

I am glad I made the breadboard effort. (I am not a linear thinker- it is a linear activity) This will make all this much easier.

Soon, I ill see what happens with a 2-y/pick up coil

@Jim,

Your diagram was perfect. I understood the diagram. I was not understanding MK1. It was my problem, not your drawing. In fact, I have not  seen such a oood set of instructions. Thank you again or your work producing this.

(waittil bill gets back and sees his jt thread eh?)

jeanna

[Pirate88179]

Geeze, I work all day and now I am even more behind.

First, a word about Ferrite. (iron oxide)  Ferrite is NOT iron, it is a ceramic.  Some toroid cores are made from powdered iron and the ones I have seen are usually painted with some color like green.  These are NOT ferrites at all.  Almost all metals occur naturally in the ground as oxides.  You do not find iron laying about or aluminum.  You find iron and aluminum oxide and these are made into the metals using a furnace.

All of the toroids I have used thus far are ferrite.  Now, as someone pointed out many pages back, there are many types of toroids because there are many variations on the mixtures used to make the ferrite itself. The same is true of aluminum oxide.  Lab testing has gone to great expense to isolate and control these variations and to be consistent about the properties of the finished materials.  A slight change in one ingredient can alter many of the properties.  The same with the firing process itself.  That is why transformation toughened zirconium oxide exhibits properties that no other zirconia does because of the firing process.

Anyway, I just wanted folks to understand this.  I spent over 20 years in the precision ceramic machining industry and we machined every type of ceramic material made.  So when someone says my 1" ferrite does this or does that, it in no way means my 1" ferrite will do the same unless it is the exact same material fired in the exact same manner.
(For what it's worth, I am also a musician.  I played drums professionally for about 25 years and when I was in college, I learned to play the guitar which I still play daily)

OK here are some photos of my 2 new supercaps that arrived today while I was away.  None of my other stuff is here yet as it is coming from another supplier.

Just thought some might like to see what 10 Farad supercaps look like.  I put a dime in the photo to show scale.  Later, I will go back and read all of the posts I missed, which are many.  Keep up the great work.

Bill

[Cap-Z-ro]

@ Mk1 and amigo,

I have great expectations from the properties shown by the j/t...and of course the pulse would have to be strong enough work with the magnets.

In my mind pulsing is the key to everything.

Regards...