Joule Thief 101

[tinman]

I choose my words carefully....I never stated that an inductor is a pure resistor. 


Please do not make the mistake of thinking that I am not informed of the difference between a pure resistor and a reactance, in this particular instance, an inductive reactance.


Regards

And please dont make the mistake that i referred to a pure resistance,as i clearly stated effective resistance.


Brad

[tinman]

Brad,

so I suggest you do the same for MH for assuming that energy has already been given to a resonant system. In fact a resonant system is resonant regardless if it is resonating or not.

You expect to be cut some slack with your incorrectly depicted probe positions and scope traces,

OK,lets clear this up first.

To quote PW : TK and Tinman's use of Faraday's law in the most general sense as a way to choose, confirm or, indeed, "predict" which waveform was correct was both elegant and quite simple.Given the information contained in Tinman's schematic, and using only the information in the above paragraph, it is possible to choose, that is, "predict", which of the two scope captures Tinman presented depicts the correct waveform.  As per Faraday, the correct waveform would indicate a minimum of induced voltage at the same period in time when the rate of change of the magnetic flux was also at a minimum (as observed by proxy via the primary current).TK (and later Tinman) clearly stated this is how they invoked the use of Faraday's law to "predict" which scope capture was correct and even included an annotated capture to further demonstrate this.

Quote TK ; Brad, your scope shot shows the expected 90 degree phase difference as predicted by Faraday's Law: The induced (negative) EMF in the second coil is proportional to the _time rate of change_ of the inducing magnetic field from the first coil.
The first coil's magnetic field follows, to first order, the current shown on the scope trace. At the peaks of this current, the time rate of change is zero (instantaneous slope is horizontal) -- and so the induced EMF as shown in the second coil's trace is zero (the induced current trace crosses the zero volt baseline at the same time the inducing current peaks.) When the inducing current (magnetic field) is changing at its maximum rate (the place where the instantaneous slope is steepest or most vertical: the zero crossing) the induced current is at its maximum (the peaks).

The original question-post 1531--:@ minnie-or anyone else that cares to have a stab at it.
OK,lets see how your laws of induction skills go. Below is a schematic and scope shot to go with the schematic.

L1 is wound on the former first-this is our primary coil.
L2 is wound over the top of L1.
The CVR is showing the current flowing through L1(the blue trace on the scope shot),and so this should be also indicating the rise of the magnetic field around L1. The current and voltage through and across L1 are extremely close to being in phase at these low frequencies
The yellow trace is showing the open voltage across L2.

Should L2s voltage trace be in phase with L1s current trace,or should it be 90* out of phase as shown in the scope shot?.
So the first scope capture associated with the schematic was correct,in that using faradays law of induction,we could determine if the phase offset between voltage and current is in accordance to faradays law of induction. The question was never about !is the polarity correct!,it was about associating the two traces phase offset with faradays law of induction,and so the scope shot is correct for the question asked.

To say the scope shot is wrong,because the polarity is incorrect,only creates confusion,as the question was not about polarity correctness,it was about phase offset between the primary current,and the secondaries EMF in association with faradays law of induction.

The question was proposed to minnie(who failed to answer)after his comment that i needed to learn the basics of induction,and so ,the scope capture was presented with the associated schematic to test minnie's skills on induction--to see if he had the right to say what he said--which turns out he did not.

To say i am wrong,or that the scope capture was wrong for the question asked,is also to say that PW and TK are also wrong.
So please do not do what MH dose,and add confusion by way of saying things are wrong by pointing out things that were never part of the question.

Brad

[MileHigh]

So please do not do what MH dose,and add confusion by way of saying things are wrong by pointing out things that were never part of the question.

I have to laugh at that one considering the near-insanity with respect to Brad pointing out all sorts of things that were never part of the two wine glass questions and using that as a vehicle to play the "wrong" card on me.

Please cite an example or two of what you are referring to with respect to me Brad.

[Pirate88179]

MH:

To be fair, you never specified white wine, or red wine in your question so...I can see how one can become confused.  Actually, I think a sparkling wine might hit resonance at a lower frequency due to the air (CO2) in the wine making the fluid less dense.

You also never specified how many glasses of wine we need to drink before answering your question.  Personally, I think 3 would be ideal but, others here may disagree with that number.  I was going to make a nice video about breaking a wine glass but, as it turned out, I did not need resonance nor sound...just gravity, ha ha.

Bill

[MileHigh]

Bill:

The Budgie from Hell will haunt your dreams for the rest of your life:

https://www.youtube.com/watch?v=sH7XSX10QkM