Oh dear.
Tell us all here how the internal combustion engine works MH,and what RPM it will be capable of achieving. Im not going to give you any specifications about the parts used in that engine,nor will i tell you if it is a gasoline engine,or a diesel engine. Im also not going to tell you whether it is a piston engine ,or of a rotary design-->but i expect you to be able to tell us what will determine the RPM of the engine --much like you asking me what will determine the frequency of a JT circuit without any component specifications.

Indeed, your example backfires on you, pun intended.  You can indeed describe how a gasoline engine or a diesel engine operates without any specifics.  You can indeed discuss approximate top speeds for different engine designs without having to be specific.

And that's what I am asking you to do since you claim you can do it:  Describe how a Joule Thief operates at a low voltage and explain what determines the frequency of operation.  That's what I did for a standard Joule Thief at normal voltages and I did it without any component specifics.  I did a complete annotation of the timing diagram.  You should be able to do exactly the same thing for a standard Joule Thief operating at a low voltage.

But the reality is that it is pure BS coming from you and you will say anything to deflect away from this truth.

i am smart enough to say when I don't know something and you clearly aren't smart enough to do that.  You are the poor guy that holds his breath and turns blue all the time.

Mistaking "voltage source" for "DC voltage" goes back to the same old language comprehension and thought process issue that you have.

If you want to prove that you are not lying about knowing how the Joule Thief operates at low voltages, just explain it right here.  You cannot claim that you understand the process and then turn around and claim that you can't explain it, that's ridiculous.   So put up or shut up.

author=MileHigh link=topic=8341.msg474965#msg474965 date=1455982986]

The term !blocking oscillator! is a bit of an incorrect description.The current flow isnt actually blocked,the current path is disconnected/becomes open--nothing is actually blocked.
Brad

I must interject here...

When operated outside of the linear mode of the transistor (digital switching), the circuit acts as a blocking oscillator.
it clips the waveform, the resultant peaks are represented by the inductor action, not the transistor, or a combination of the two.

The premise of the discussion I began with, took the transistor out of this digital mode of operation.
Thus, MH's perspective does not apply to the JT in resonance mode.
But is not necessarily untrue.

Tried 3 different transformers, all with equal 1 to 1 turns on the primary and trigger coils. In all cases once I get them to be in the clean sine zone, there is very limited range in which I can get it to show before it cuts out completely. So maybe a different ratio of turns would be next.

I can see that when the circuit is running normal with say a 1k resistor, that there is more on time of the transistor than off/discharge. So I would like to change things to possibly get a near to equal on/off time when running normal mode, which would hopefully help in producing the sine, instead of the long on and short off time Im getting which would kill off any ringing of resonance if the on time is too long.

I suppose that more trigger turns would shorten the on time as it would increase the base voltage in a shorter time period than with a 1 to 1 ratio. So Ill go that route for now.

Mags

Ok. Just played with the larger transformer I had made for a project way back. With it, I did a sloppy 3rd winding shorted. With a fairly low ohms on the resistor value, I can get from an almost normal waveform, stronger n longer downward curve from the top, to the ones below. Both are set to the same parameters but one with a weak battery and one with a fresher battery..  So I must be close as the freq shown on the scope is the exact same with different voltage levels. Where before when the voltage changed, if it went lower, the freq would be higher. But here it sticks.  Man. Im glad I conjured up using those shorted windings.  I havnt gotten what seem like Im getting here without it.   

Will try to tune it with the 3rd winding by adding or deleting turns. Gotta tighten it up and solidify how and where it sits.

Farted around with the disk caps and there were points where the freq just jumped to another octave when adjusting the pot. And would jump back down when I turned it back. When it jumped down, the led was bright, and got brighter as the resistance was lowered. But on the way up, right at the jump area you can see an area of transition where the led is very dim, then as bright or more than below that point when in the higher freq jump. Also the batt voltage had shown down around 1.12v just below the transition and 1.33 above, led lit very well on both sides. Will do those things again with scope shots.  I had just found this more interesting to show for now.


Mags

Here are 2 shots of different led placement. 1st is across transistor as in typical circuits and the 2nd across the coil.

Resistor is 22ohm. Will try my 1ohm resistor block for a power in measurement for each later. Gota work today.


Mags

Sorry to interupt but I just have to ask , what happens if you put say 50 volts in , will it run a load that needs 120?
I tried to build a JT ,could never get it working.
Can you up the output enough to run larger loads?
I'll understand if none answer.
artv

 author=MileHigh link=topic=8341.msg475054#msg475054 date=1456045528]


How a Joule Thief works:  https://www.youtube.com/watch?v=0GVLnyTdqkg

Stop beating around the bush and put up or shut up.
[/quote]

I never even asked you the question with respect to the EMJ story so it is impossible for me to "fail to provide enough information in my question."

I will take that as a no--i cannot answer my own  question.

I think somewhere in this thread there are about 10 words from you about how a Joule Thief supposedly operates at low voltages.  Is that your "working theory?"  If that is all you have, then copy and paste it here and add a lot more than that.

Like i said MH--you do not read all of the thread's. I think you more !pick and choose! bit's and pieces that suit your need's. The post with my explanation is closer to 400 word's with scope shot's. Some how you managed to miss that But you will look silly-!even to your self! when you find it--after your continual banter about me posting a description of how a JT works at low voltages--something you your self couldnt do.

For example, I am sure that if you wanted to describe how a gasoline engine works you could write up a full page of text description.  But we are NOT talking about gasoline engines, we are talking about how a Joule Thief operates at low voltages.

It was you that said you can determine how a gasoline engine works,but you also asked what determines the frequency at which a JT would oscillate--so i asked you to show what determines the peak RPM of a gasoline engine,without me giving any specifications of the parts used--just like you refused to give me any specifications of the components in the JT circuit you wanted me to explain.  Like i said MH--it cant be done without these specifications. For example-if i make up a circuit,and use a set length of wire for each coil, and use a ferrite toroid,then the JT will oscillate at a certain frequency. If i do nothing other than change the ferrite torroid out for a steel laminated torroid(while everything else remains the same) then the frequency would drop by over 1000 %.

So you see MH,there is no way of saying what the oscillating frequency would be for a JT circuit without the required specifications-just like you could never work out what the peak RPM of a gasoline engine would be without those specification's-nor that stupid and incomplete question you asked EMJ. You try and trap people like this all the time MH--but they are all waking up to you.

So as i !HAVE! answered your question in detail(although some how you missed it),you now answer your own question you gave EMJ,with only the information you provided
What happens when you apply a voltage source to a coil ?.

You cannot answer your own question MH--you know that,as there is not enough information to answer it.
Is the voltage source an alternating source,or a direct source.?
Will there be enough current available to maintain this voltage source when it is applied across the coil?.
What kind of coil?. E.G-dose it have a hole through the middle,or is it tightly wound from center-out,so there is no hole through the middle-->this will determine the magnetic field produced by the coil.
What kind and size of wire.
How many turns?
The list go's on MH.
Your question cannot be answered without further information-->your question was loaded--a bait for EMJ-->just like your question on what determines the frequency of oscillation in a JT circuit. That list is about a long as the required information needed to calculate the peak RPM of a gasoline engine.

Please explain to the readers how a Joule Thief operates at low voltages.  Please see the attached annotated timing diagram and the linked YouTube clip as examples of how you can make an effective presentation.

As i have said a number of times now,i have done this already--but you have some how missed it.'
Im not doing it again MH,just because you lack the ability to read all parts of a thread.

Now,how about you answer your own question-what determines the frequency that a JT will oscillate,and i will add everything you failed to take into account.


Brad

Right so you are "fighting" with me and you are so immature that you refuse to link to what you are talking about.  So you will get your jollies when I go look for it.  Get yourself a box of Kleenex.

As expected

https://www.youtube.com/watch?v=QFM9fxfONVw