The way I see it a circuit that is provided a signal from a microprocessor to switch the primary, without any feedback for "auto resonance" is not a joule thief. I might be wrong. But to me it would just be a switched transformer. More akin to a solid state Tesla coil if air cored.

I have used different IC's and micros to provide the signal to switch small Tesla coils, they are no Joule thieves. To get resonance the frequency must be varied slightly at times and a load means it or the L/C needs to be changed to keep resonance. For without the resonance the power is much less. Personally I would have thought a mosfet would be the best switch for such a setup.

It would go like this, Microprocessor - mosfet driver - mosfet as a low side switch.

Cheers

Well I know from experience that when I excite a transformer with a pulse train signal and switch it with a mosfet, I get the most power out when the secondary is tuned to resonance, just because most joule thieves might not work at resonance or a harmonic doesn't mean they would not work better if they were made to do that.

True a Joule thief is a self oscillating circuit not needing to be in resonance.

But I see the self oscillating feature as a basic part of what makes a joule thief a joule thief.

http://en.wikipedia.org/wiki/Joule_thief

First line on the Wiki.

A joule thief is a minimalist self-oscillating voltage booster that is small, low-cost, and easy-to-build; typically used for driving light loads.

The difference between the radiative and receiver effects between an out of resonance and in resonance small Tesla type transformer/coil is great. With no resonance the fluro held in the hand won't light so well, the voltage at the terminal is much less and when a direct load is placed on the terminal eg. the fluro is touched to the terminal the transformer goes out of tune, if the L/C is adjusted or the frequency adjusted to keep resonance the voltage and power peaks.

Just going near the coil will affect it's tune a bit but actually touching a fluro to the top terminal changes it a lot, and with a manual frequency pulse width adjustment it must be tuned for the load, or tuned to excite a receiver with load, or tuned to just oscillate at resonance with no real load so maximum radiations are forced.

Just because a circuit can use it's battery right down doesn't qualify it as a joule thief to me.

Cheers

P.S. This Armstrong oscillator variant kinda shows that if I touch to the secondary the fluro it lights better than if I touch it to the top terminal because it affects the L/C less.
Towards the end of the video I show some cool patterns in the fluro, which is not new to me I've made a lot better cool patterns in other video's.

It's not a joule thief because it requires over 10 volts to run but it does self oscillate.

So can anyone explain why there are dark and light bands in the fluro ? And why they can move from either end to the middle or from either end to the other end ?
https://www.youtube.com/watch?v=xz_pSsZtUZo


These below are oscillator driven, not self oscillating.

This video shows the power of resonance, at the receiver transformer. Even though the power is low the difference between resonance and no resonance is great. Right at the end of this video clip you can see the neon and hear the "escaping gas" sound it makes when brought close to the transmitter terminal.
https://www.youtube.com/watch?v=jJgHWYTk6_g

Another different freaky fluro pattern
https://www.youtube.com/watch?v=Gr9JX_sIP2I

My self, I prefer oscillator driven (at full frequency, not a harmonic) and manually adjusting the LC and frequency-pulse width ect.  Just my preference. Which is pretty much what your circuit would do wouldn't it.

I have thought about using feedback to a micro, but only so much time to spend.

..

source for JT boiled potato battery

http://www.youtube.com/watch?v=36hzlFVgVa8


http://blogs.smithsonianmag.com/ideas/2013/12/a-potato-battery-can-light-up-a-room-for-over-a-month/?utm_source=facebook.com&utm_medium=socialmedia&utm_campaign=12032013&utm_content=innovationspotato

 

source for JT boiled potato battery

http://www.youtube.com/watch?v=36hzlFVgVa8


http://blogs.smithsonianmag.com/ideas/2013/12/a-potato-battery-can-light-up-a-room-for-over-a-month/?utm_source=facebook.com&utm_medium=socialmedia&utm_campaign=12032013&utm_content=innovationspotato

Interesting that boiling the potato helps the power output.  Excellent research.  I saw no mention of any JT circuit so, if they make enough juice to light that one led, then the addition of a JT circuit could enable them to light hundreds from the same power input.  Maybe they will figure this out?

Thanks,

Bill

Now if they could make a battery without the metal electrodes...

Hi all,
electricme! here 


Still around, have been busy, just popped in to say


Merry Christmas to all those who still remember me from years gone by for 2013


and all the best for the New Year


Jim from the land down under 

Hi all,
electricme! here 


Still around, have been busy, just popped in to say


Merry Christmas to all those who still remember me from years gone by for 2013


and all the best for the New Year


Jim from the land down under 

Jim:

It is great to see your post here.  Ahhh, it is almost like the old days again.  The old JT circuit has not yet shown everything that it can do.  I do hope that you will one day soon be able to post here with your experiments and research.  We need minds like yours.

We should organize a JT topic reunion, ha ha.  That would be great to have everyone back here again. 

Merry Christmas to you and a Happy New Year as well.

Bill

PS  Do you wind your toroids in reverse direction down there?  Ha ha.

Joule Thief Shorted

http://www.youtube.com/watch?feature=player_embedded&v=NFowJ-SqEi8