Joule Thief

[xee2]

@ jeanna

The 3" toroid circuit with 2B-10C-80P coil will also work at low voltages just by decreasing the base resistor value. But I do not think this is good choice for a long duration circuit.

[electricme]

@stprue,

@ electricim

Re: Method for converting HV (static) into usable low-voltage power.

Do you think a similar method on a smaller scale could work for a JT?

hmm, hard to answer this, before I do, let me say I have been away since friday, so I have some catching up to do first, ohhhhh this thread is so dynamic, makes the head spin at times.
For instance, I have a completely new toroid wind to read up on, phewwww, lol

OK that said, the answer is yes, take a look at how the aerial wire picks up energy and is fed into the "top" of an ignition coil, one of the 2 secondaries go to earth, the other to the Batt, but this off the cuff and I will have to check it out for certantity.
Although using this method, you will need to take precorsions, to bleed off any very high pulces by using a series spark gap arrangement, it is able to regulate it, say 3 X .1thou gaps, just 3 bolts setup next to each other eg,

Aerial end connects >>--------[bolt head 1] [Bolt head 2] [Bolt head 3]------wire to earth
                                          | wire to circuit connects here                     |
                                          |                                                             | 
                                          | circuit                                                 -----
                                                                                                       ---
                                                                                                         -


I'm on P773 and reading,,,,,, chugga chugga chugga lol

I have just finished reading catchup, wow was there a lot this time ha.

To answer stprues question, by chance, and I don't believe in chances, I came across this web address, over the weekend while I was away, I didn't know stprue was going to ask me the question.
  http://scene.org/~esa/merlib/radiant_energy_antenna_system.pdf 

Now there are 2 circuits, charging a 12v battery, by aerial power, the HV pulses are switched via the negative, guess what! there is a neon involved toooo. lol.

It wouldn't take too much to develop this circuit as an addon to the Joule Thief to charge batteries.
Mabe, even have aerial power asist to power the toroid itself.

jim

[jeanna]

Hi Jim, Nice to see you again. I hope your weekend was charming.

@All,
I have been reading the Tesla lecture delivered in London in 1892 this evening. I came across a very interesting paragraph.

Just in how much a very high frequency is essential for the production of the results presented is a question which, even with my present experience, would embarrass me to answer. Some of the experiments may be performed with low frequencies ; but very high frequencies are desirable, not only on account of the many effects secured by their use, but also as a convenient means of obtaining, in the induction apparatus employed, the high potentials, which in their turn are necessary to the demonstration of most of the experiments here contemplated.

So, my brain realized the reason high frequencies are so important is (as he says right here) to produce the high voltage needed.
It is because the back emf can and will happen every time the switch occurs, and a high frequency means that the switch occurs many times.
This also makes his comment about the rate of change make more sense to me too. This is the suddenness of the switch, and if the inductance and the reactance are happening more sharply, there will be more and higher voltage resulting.

Ahh, I can now understand why he was telling us at another time, that although frequency was very important it wasn't the frequency itself that mattered.

OK, I will go back to the reading corner now.

jeanna

[electricme]

@all
GOD is so good, 
lol last week I had a "good winge" about unfair gov policy to not allow me to use my aircons, etc etc.
http://www.news.com.au/couriermail/story/0,23739,25685730-3102,00.html
This not where I originally heard about it, but you will get the "gist" of it.

Well guess what, I went along to my favorite scondhand junkman place in town, and there I spies me a big generator (ex army). I don't know what model it is, the pull rope works, and there is 3 HD electrical outlets. It is adjustable from 120volts - 240volts, the gauges say it can handle up to and looks like over a tad of 100 plus amps, its sprayed all over in dark (faded) green paint.
The best part, He he, I got it for $100 ausie dollars, yipeeeeeeeeee.
I don't even know if it works or not, got to flush out the bad petrol, it has a magnito, no battery.

If anyone recognises this unit from the pics, and can let me know its model, where I can get a operaters manual etc etc, please poste in this thread, or send me an email TA
 
jim

[xee2]

Low battery voltage tests on 3.38" toroid with 100 ohm base resistor.