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Author Topic: Joule Thief  (Read 6276921 times)

TinselKoala

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Re: Jule Thief
« Reply #15885 on: December 02, 2012, 01:57:22 AM »
I just got to get me some of them magic crococlipleads!

Meanwhile... it's now almost 1900, and I am still sitting at 1.322 Volts...... that is a decrease of one millivolt in 25 hours.... I've seen it go down to 1.318 volts then come up a bit, maybe a loose connection to the voltmeter....  early this morning I took the green LED off and put a white LED with a 22R series resistor, put the LED in a ping-pong ball as a diffuser, it's glowing eerily .... other than that I've made no changes.

ETA: My FedEx boxes came through today! Much worse for wear, paperwork missing, but the Tex 2213 scope and the Topward dual power supply are intact and working.... whew. TriField meter ditto. I don't know if there was anything else packed because the inventory lists are missing.... I hope the Shimpo got left out of the shipment somehow and is still safely at the other undisclosed location, safe and cold.


TinselKoala

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Re: Jule Thief
« Reply #15886 on: December 02, 2012, 07:32:51 AM »
Oh come on. Now it's midnight 30, and the voltage is creeping up again. It dipped to 1.321 but now it's 1.322 with the last "2" trying to flicker over to "3" and stay there. This time it's not due to any loose or intermittent connection. The thing is just sitting there, glowing eerily, running on nothing. Well..... at least the charge isn't depleting.
Where is the "nothing" coming from? Now that my boxes have arrived and I have my trusty TriField Meter.... I can tell that there is a lot of magnetic field activity around and near my workbench. I have power lines all over the place, I have power supplies and scopes running (two now, whooopie), but I don't have the maze of clipleads that could be picking up power, just the compact build with the tiny coil with two magnets. And this house has a metal roof, and it is in a "radio dead" zone, the reception of both AM, FM and VHF too is terrible in this block.
I guess it's time for a field trip.

synchro1

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Re: Jule Thief
« Reply #15887 on: December 02, 2012, 10:29:52 AM »
@Tinelkoala,
 
               That circuit has to be tuned close to perfection to balance the charge so long. Do you use a permanent magnet anywhere in the circuit? 

TinselKoala

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Re: Jule Thief
« Reply #15888 on: December 02, 2012, 02:47:26 PM »
@synchro: Yes, the little choke coil that I wound with the extra windings has a magnet on each end of the ferrite spool making its core. It came out of the TV like that. I have two other similar coils from TV sets that also came with magnets installed.
The voltage is showing 1.319 right now, at 0745.

synchro1

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Re: Jule Thief
« Reply #15889 on: December 02, 2012, 03:16:55 PM »
@TK,
 
      I wound some tiny spiral coils that peformed the magnet blocking experiments very well. I wonder if a pair of "Variable Flux Resistor" spiral coils might be of help fitted in between the magnets and the ferrite core. A 6 volt JonnyDavro buzzer to transistor base and pot is a cheap PWM for this tiny coil. Additioal disk magnets on each end would allow one to adjust the ferrite Gauss to the current flux level or a bit to each side to turn the power up and down. 

TinselKoala

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Re: Jule Thief
« Reply #15890 on: December 02, 2012, 11:46:58 PM »
Yes, varying core saturation can produce many interesting effects. The MEG is an electronic system based on this idea and the eOrbo and ssOrbo of Steorn are also dependent on varying core saturation, in a mechanical and an electronic implementation respectively. The "Mag-amp" or magnetic amplifier has been around for a long time.
I've got that long toroidal ferrite "bead" that I used in the toroid winding demo video wound with some toroidal wraps, then I put a circumferential wrapping around the outside. It is very interesting to  monitor this coil on the scope while the other wraps are doing the "JT thing" in a Joule Thief.
I just put into operation my current-limiting PS, and now I'll be able to see what happens to the JT when I energize this circumferential coil which will change the permeabilty/saturation level of the core.

The "thing" is now, at 1645, back up to 1.320 V from an earlier low about two hours ago of 1.318 V. The only thing that has changed is that I've turned the window air conditioner on to reduce the mugginess in the DeepBunker. Could my instruments and/or this circuit be that sensitive to temperature and humidity?

e2matrix

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Re: Jule Thief
« Reply #15891 on: December 03, 2012, 01:06:54 AM »
Here is a point to consider when looking at very small voltage increases in this circuit.  I'm not sure if this applies to 5mm type LED's but I know that the surface mount type higher wattage LED's like 1 watt and up will create a voltage and act like a solar cell when exposed to a light source - Sun or even room light could create a small charging effect from the LED.  That would not account for the effect Gadgetmall had and especially not the runaway one but it might account for some other small voltage increases in the circuit.  I discovered this when I had an LED flashlight that would not turn on if it's pointed at the Sun (a design booboo by the mfgr.).

NickZ

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Re: Jule Thief
« Reply #15892 on: December 03, 2012, 02:40:32 AM »
  I do use a permanent magnet next to or under my various Ringer's transformer coil. It does change the circuits frequency, but I don't see much difference in the actual voltage output, or bulb brightness. You can hear how the frequency is raised or lowered in pitch.  I go by the volume level of the ringers' tone, not the higher or lower pitch, but the volume level increase of the ringing. The more noise it makes, the higher the output. There probably are sweet spots, though.

tysb3

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Re: Jule Thief
« Reply #15893 on: December 03, 2012, 07:04:26 AM »
hi TK,
its maybe help for you:    " Just completed my first experiment. What I found: battery voltage much depends on the temperature."

http://www.overunity.com/8334/second-stage-joule-thief-circuits/msg237123/#msg237123

TinselKoala

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Re: Jule Thief
« Reply #15894 on: December 03, 2012, 08:31:44 AM »
@tysb3That is excellent work! Real data carefully gathered and properly presented. I am so pleased with you.... that I am not even embarrassed that we seem to be covering old ground again. It looks like there was a lot of good work done in that thread that I have been completely missing.
I also am amazed by the pulsetrain graph right after your temperature plot. That is exactly what I saw when my LSJT first began to oscillate! It would make groups of pulses just like that, same appearance and timing and intervals. This effect didn't last for me, though and now the circuit is making continuous oscillations. I don't understand what I did to make it do the groups like you show.
Your temperature graph seems to reflect what I'm seeing. There is a slow overall decline, with periods of steady voltage and some periods of slight climbing. I haven't been keeping good records but my impression is also that warmer temperatures make the voltage go up a bit.
Again... thank you so much for posting the link to your earlier work. That is the way to do it!

Billxx

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Re: Jule Thief
« Reply #15895 on: December 03, 2012, 03:53:45 PM »
Just an observation, but, I think the use of a magnet in the circuit near the transformer offers an opportunity to harvest energy. Gadgetmall's discovery of being able to self charge his battery may be because of the position of his washer magnet in relation to his transformer. The runaway condition he experienced may be because once you start the "generator" effect, it could be causing a compounding effect, and really no way to stop it without complete disconnection. He might or might not be able to replicate that condition again because he may not be able to position his magnet-transformer relation exactly. It's really a cool discovery he made, though.  :)

gadgetmall

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Re: Jule Thief
« Reply #15896 on: December 05, 2012, 01:04:29 AM »
Hi guys . I have no idea why some work one day and not the next . Very strange circuit . I read about the results from temperature . Than don't make any sense to me as they are inside and the same temperature day or night.One thing i know that changes at night verse the day besides outdoor temperature in the ionosphere and it's ability to carry radio waves better at night due to no noise from the suns electrons. I have noticed just the oppisite from Tsby3 .

Also i am wondering if solar flares were acting up as several nights ago i saw some auroras in a bluish color . We rarely get them in the east but i have caught them lighting the skys here now and then.. Has anyone seen the new 3D images of the sun from the Nasa Stereo satellites . Simply Fantastic on my 3D tv . They show exact images in depth and even the rays and particles penetrating our atmosphere and hitting objects and b ringing down Grids and stuff . Unreal power lately as our sun spits at us.

I could be that i have fine tuned to a stations frequency that blasts at night time but still remains in the day. the only other explanation is there is some kind of energy that can be tapped with the proper coil and frequency .

I hate it when i see something that is so fantastic and i can;t do it again. Yes i have tried rewinding that little ferrite rod with the same wire and used one of the same germaniums in the same spot on that board  and the best i can do is hold a steady voltage for a few days then that ones slowly fades .

i do have two there still running thought but not a wire melting led blowing transistor frying circuit . So i have build another board to test different coils and transistors more easily and can post on those.
In the meantime guys there is still lots to learn from just this one little circuit . I am also tinkering with several transistors in a push pull for the secondary stages that will feed that base of the Q1 primary ..



I am heading to the surplus yard tomorrow looking for that unusually military piece of something  i can use do looking forward to that . Also almost finished with Soln1+  and need to sell it so i probably will make a short demo of it . 


BTW , forgot to mention that this got dang circuit took out the sensor circuit in me Weller soldering station(24v) .the pencil looks like a piece of hot iron a blacksmith could pound into a horseshoe now.  So WARNING . don't use your good temperature controlled soldering station on the crossover circuit when it's live . The stray emf creeps right thru to your mains and takes out anything between it .

TinselKoala

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Re: Jule Thief
« Reply #15897 on: December 05, 2012, 03:32:50 AM »
Hmmm.... that last bit is kind of scary, I use my Solomon temperature-controlled iron on it live sometimes..... have to be more careful I guess, I can't afford to blow that iron for sure.

Am I reading right, gadgetmall, that you've not been able to recapture that great supercharging effect yet? That's a bummer... I really want mine to do that for a while, too!
I switched to a NiMH AA cell and it started at 1.320 volts and went down in an hour to about 1.295 and now has seemed stable there for some hours.... I hope you saw the video where I use a variable cap for the 100pF and show its effect on the waveform... .got any ideas which way I should tune, I mean what kind of waveshape I might want? I think by adding another 200 or 300 pF I can even extend the effect I showed on the waveform further, bringing up the voltage (less negative) of the "level" portion after the spike and before the little ringdown, and making the frequency lower. But is this the direction I want to go? By using the minimum capacitance of my trimmer, about 10 pF, that "table" gets lower in voltage (more negative) and the frequency increases. But the current trace hump seems to remain pretty much the same, although the average current will go down as the frequency decreases. I dunno, still running it on the NiMh.

Pirate88179

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Re: Jule Thief
« Reply #15898 on: December 05, 2012, 04:24:58 AM »
OK, this might be stupid and not relevant but, have you guys considered using a super cap in place of the source battery?  The reason I ask is because of what I learned a while back while working on projects here on OU.

Most, if not all, JT type circuits output some really nice spikes, some of which are hard to see on a scope unless you really play around with it.  These little flashes are, I believe, a good source of energy that a battery just seems to ignore but a supercap captures and stores it for later use as real energy.

It is hard for me to explain but, this is the simple reason that my earth battery, which on the meter or scope, puts out just under 2 volts can charge a 2.7 volt boostcap fully.  It is all of those nice high spikes that get saved by the cap. 

Anyway, this is my explanation for it and possibly, getting rid of the batteries all together might just make the difference in these circuits. If I am way off base here then just carry on and keep up the great work being done here.

Bill

xee2

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Re: Jule Thief
« Reply #15899 on: December 05, 2012, 06:28:54 AM »

I hate it when i see something that is so fantastic and i can;t do it again.



When working with RF frequecy circuits it is necessary to remember that the leads are also components. The capacitance between a few inches of two wires can look like a short at RF. So the connection wires need to be duplicated as well as the components in order to get the same results.