Joule Thief 101

[MileHigh]

Brad:

So you see MH,the joule thief is not one single circuit,it is a name used to describe an effect,and as i said,there are many different types of circuits that can achieve this effect.

You are doing nothing more than playing a bait and switch game again.  It's very frustrating.

I showed you a standard Joule Thief circuit and you said, "That's an RLC circuit."  That's wrong - it's not an RLC circuit.

Now you are pulling off the switch and saying, "Oh no, there are many Joule Thief type circuits and I am talking about other circuits."

The answer to that is no - no bait and switch nonsense is acceptable.

Nor am I convinced that the other circuits will do what you are saying.  If you want to make a case and demonstrate what you are saying then fine, but throwing words at the issue like you are throwing spaghetti against the wall is not going to work and the spaghetti is not sticking.  Electronics simply doesn't work like that and you actually have to put some substance behind what you are saying.

MileHigh

[sm0ky2]

We have heard MileHigh's objection.  It will be what it is.

Does anyone else disagree with what I have presented in this thread?

And if so, please enlighten me.
I would love to hear other perspectives concerning the nature of this technology.

I have no problems admitting if I am wrong, as I have been forced to do so in the past.
I can't claim to know everything about everything,
in fact im not sure there is "anything" I truly know "everything" about. (yet?)

I am always open to learning new things.
That being said, after over 10 years of experimentation with this type of circuit*, I feel that I am competent enough to engage in analytical discussion of its' nature.
This was not always the case, in the beginning this was a new and strange phenomena. (Armstrong/Steven Mark)
then the JT came along and that had its' own peculiarities. (ULV - ultra-low-voltage modes of operation)

Seeing that (from my perspective) the circuits are analogous,
it was instinctive nature to apply the concepts given to us by Armstrong,
to all circuits that are Armstrong analogies.
[* - I consider all Armstrong analogies to be variations of the Armstrong Oscillator.]
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I didn't really want to get into this part of the topic discussion, because of the implications involved......
But since I already (oops) opened Pandora's box, im sure that as soon as people start to "get it", they will ask me these questions concerning the feedback loop.

So, in accordance to Armstrongs equations, the feedback loop, (when phased (reflectively) to precisely 180-degrees from the resonance, and with appropriate capacitance and impedance)
is reversed in phase, so that it cycles back into the loop IN PHASE!!!!! -- this is an advanced concept in resonant circuits.
And the positive feedback represented by the feedback loop is in addition to the constructive interference effects of an SRF resonant node.
This phase reversal effect was commented on by another user above,
and while this was only the effect of the particular methodology of measurement, it shows the effect quite clearly.

If you do not understand the basics, as presented in the past few pages, please go back and learn that before attempting to understand what I just stated.

What we have at this stage, is a JT operating at maximum efficiency, with a positive feedback.

For positive feedback to be effective, its' magnitude must be overcome circuit losses.

Since feedback, (of any resonant form), is of lower amplitude than the original signal,
In order for this to cause constructive interference, the system losses must be less than the difference between the two.

The frequency at which this occurs is a factor of the capacitance of the Non-Inductor part of the circuit.
This includes a factor of the battery, the transistor, the resistor as well as the diode(if used).
This is separate from the resonant frequency of the feedback loop as mathematically defined in the previously posted equations.

All these factors must be coordinated to achieve "total circuit resonance".

This YouTube user gives a very well done explanation of this, in the earlier part of this video.
https://www.youtube.com/watch?v=5StwZCeNzVU
I believe this individual to be at a more advanced level than myself. Which has made his work of interest to me, for no other reason than that...
[He is able to apply discrete functions of a crystalline structure, while maintaining coherency of the resonant frequency.
That is just mindboggling if you ask me...., We didn't even get that deep in Computer Engineering classes]

Although the oscillator used in his Armstrong Circuit is a piezoelectric quartz oscillator, the concepts apply exactly the same.
(transistors are comprised of the same silicone element, the primary difference being the atomic resistance across the oxygen bonds, which is negligible in this application)
Also, the laws of induction apply (within proportion to particular materials constants) to all oscillators, not just quartz.

The pertinent information is near the front part of the first half of the video.
He talks about a lot more than what I reference here, because he is building an amplifier,
but if you can keep up, there is a lot of good information to be watched there.

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Most people that take a glimpse of an overview of Edwin Armstrong, and a general sysnapsis of his oscillators:
say one common thing -  "If this is so great, why don't we still us it?"

Because of this, i set myself upon a quest to answer THAT question.
The answers to this, are what led me to studying what Armstrong had to say.
This is actually more intriguing than most other energy technology suppression events throughout history.
Simply because it occured at a time when such supression was not common, and the tactics of suppression applied today had not yet been developed.
In other words "it was obvious", and imbedded in the historical record of Radio.

The efforts to suppress Edwin Armstrong's technology became the foundation for Non-Resonant propaganda in electronics theory.

This sounds like a ridiculous conspiracy theory, but look it up.
It actually Happened!

He was building radios with a vacuum triode that powered themselves, AND caused great interference with transmitters, receivers, and transceivers for MILES around!!!!

Pay no attention to the man behind the curtain......

[MileHigh]

Smoky2:

There is a great PBS documentary about Edwin Armstrong and the battles he fought in the early days of radio called "Empire of the Air."

http://www.pbs.org/kenburns/empire/sketches/

http://www.imdb.com/title/tt0238199/?ref_=fn_tt_tt_1

He invented a lot of great radio circuits and he also invented FM radio which was an amazing accomplishment.  It's very sad that he got squeezed out and obsessed on his battles and eventually took his own life.

But there is no "suppression" or "Non-Resonant propaganda" in the electronics industry.  You are back in "good shepherd" mode.  He didn't build radios with vacuum triodes that "powered themselves."

If you are really interested in old radio circuits and perhaps even want to talk to a serious expert in all of this stuff, check out this guy's YouTube channel:

https://www.youtube.com/user/AllAmericanFiveRadio

The guy is a radio genius and can fix all radios going all the way back to the 1910s.

MileHigh

[Magluvin]

Magluvin:

Great work and you are doing it right.  Exercising the circuit and seeing what it can do helps others.  So far your waveforms show a standard Joule Thief operating in standard switching mode.

I attached a standard Joule Thief schematic showing two test points that I suggest you connect to your scope channels.  Both test points would be relative to the battery ground.  One is across the LED and the other is at the input side of the base resistor.  You notice that the two test points are for the bottom contacts of the Joule Thief transformer.   So by viewing the two test points you see all of the "action" around the transformer.  Notice that you can also easily derive the current going into the base input of the transistor.  It's just the TP1 potential minus the transistor Base-Emitter forward drop (about 0.7 volts?) divided by the value of the base resistor.  So that allows you to "see" the base current.

When the transistor is switched ON, you know there is a ramp up in the current through the main coil.  Likewise when the transistor switches OFF, you know that there is a quicker ramp down in the current through the coil as the stored energy in the core does a "burn" through the LED and it is also helped along by the supply battery supplying some energy (for a standard Joule Thief).  By looking at TP1 you can make inferences about the LED current also.

MileHigh

Ok. Ill do that up tomorrow. Putting a sub box together for a GTI. Allnighter. 

Letting the JT run down the battery.  I left it at around 1.6khz  its down to 1.5khz now. the batt started at 1.2v. After posting the pics I did the increases of resistance then set it back and let it run. The batt is down to .7v already.

Mags

[tinman]

Brad:

You are doing nothing more than playing a bait and switch game again.  It's very frustrating.

I showed you a standard Joule Thief circuit and you said, "That's an RLC circuit."  That's wrong - it's not an RLC circuit.

Now you are pulling off the switch and saying, "Oh no, there are many Joule Thief type circuits and I am talking about other circuits."

The answer to that is no - no bait and switch nonsense is acceptable.

Nor am I convinced that the other circuits will do what you are saying.  If you want to make a case and demonstrate what you are saying then fine, but throwing words at the issue like you are throwing spaghetti against the wall is not going to work and the spaghetti is not sticking.  Electronics simply doesn't work like that and you actually have to put some substance behind what you are saying.

MileHigh

https://www.youtube.com/watch?v=5Mbp1iuB7as

https://www.youtube.com/watch?v=13IBcCRNF9g

https://www.youtube.com/watch?v=UPHfqQFCNtw