Joule Thief

[PaulLowrance]

Sorry gadget, but you can't expect newcomers to start reading through these pages. If it wasn't posted 5 pages back then I'm not reading it. And I see nothing wrong with drawing your circuit the correct standard way. Newcomers are probably not aware of the gadget circuit drawing standards.

As it stands, there is still questions about your circuit drawing.

Paul

[gadgetmall]

Okay, thanks. I'll wait for gadget to confirm the circuit and see if the "1 watt" LED is optional. I'm not here to chop apart his circuit or judge it, or make any assumptions, but just draw it the correct way, and then build it.

Paul

Hi paul . Its not an option if your replicating My circuit It causes an effect of reducing the current input as  Jeanna and mk1 and ist and well every one else will tell you  . If you use the EXACT parts you will get THE EXACT results !! If you dont then you probably won't .
Thanks for the interest .

GADGET

[poynt99]

@poynt
Yes, but 2 of those windings are joined and they are actually one centertapped winding.
The reason for much confusion is that this centertapped part which is essential is often missed.

jeanna

Technically, the two connected windings are not a center-tapped winding. They are wound bifilar, and connected in series-adding. They are in effect two primaries connected in series, and the output winding is a secondary driving the LED.

A center-tapped winding or transformer is one continuous winding that has a tap somewhere along its travel. This is quite different than what we have here on the JT.

I think you would find that the circuit would work equally well if the three windings were put on separately, and the two which are connected could be done so as a true center-tap. The coupling due to the core is quite good I imagine, so it probably makes little difference how the windings are put on.

.99

[jeanna]

Ive been getting reasonable results off of two identical axial lead inductors placed parallel (and reversed ) to one another.

..8.5 volts on one and 35 volts on another setup... unfortunately this doesn't produce the spectacle that other joule thief circuits do, but it's worth noting that the configuration is similar to my 2 coil Helmholtz setup.  I"ve tried placing a tertiary, but i'm limited by proximity, size factors make the circuit cumbersome to put on a breadboard..

....

Hi jadaro,

I think there are 2 things missing from making separate inductors like this.

1- as you noted, you cannot get them close enough to each other to make a proper secondary and

2- the toroid shape allows the magnetic flux to stay within the inductors. It switches back and forth depending on lots of things-basically tuning, and because the magnetic flux is not dissipating or radiating (much) it continues to oscillate with little to no work added.
In these circuits with secondaries, the only work needed to be added is just what it takes to run a transistor.
And that is less if the transistor is off much of the time as it is when the base resistor is a high ohmic value.

These are just some ideas based on my experiments and conclusions I have made based on what I have tried.

thank you,

jeanna

[Pirate88179]

Sorry gadget, but you can't expect newcomers to start reading through these pages. If it wasn't posted 5 pages back then I'm not reading it. Paul

@ Paul:

Gee, you want everyone to drop everything and help you and yet you can't take the time to read back more than 5 pages?  What's up with that?

Also, just to let you know, I noticed how you were badgering Slayer007 about his drawings on Dr. Stiffler's topic and demanding that he post them your way.  Well sir, we do not put up with that over here.  These are a great bunch of hard working, helpful folks here who have tried to help you. We will not put up with any one that comes into these topics and makes demands and yet can't take the time to read what is already out there.

Just letting you know for the future.

Bill