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Author Topic: Joule Thief 101  (Read 797720 times)

Offline MileHigh

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Re: Joule Thief 101
« Reply #2415 on: May 12, 2016, 12:54:13 AM »
I agree, but this is being approached from the other way, discussing an ideal inductor. Ultimately the whole thing is a tempest in a teapot.  If you truly understand a real inductor then by definition you have to understand an ideal inductor.

If all of the coils in your motor point with the same polarity outwards, then you probably have a lot of flux cancellation between adjacent coils.  I am assuming that you measured the inductance of a sample coil with an inductance meter.  Do you know if the inductance meter can be thrown off by the high 650 ohm resistance?

If you are not sure about the total inductance then you could easily measure the time constant for all of the coils in series and see what you get.  I would not be surprised if you get a lower inductance than you think.

Offline Magluvin

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Re: Joule Thief 101
« Reply #2416 on: May 12, 2016, 01:20:54 AM »
I agree, but this is being approached from the other way, discussing an ideal inductor. Ultimately the whole thing is a tempest in a teapot.  If you truly understand a real inductor then by definition you have to understand an ideal inductor.

If all of the coils in your motor point with the same polarity outwards, then you probably have a lot of flux cancellation between adjacent coils.  I am assuming that you measured the inductance of a sample coil with an inductance meter.  Do you know if the inductance meter can be thrown off by the high 650 ohm resistance?

If you are not sure about the total inductance then you could easily measure the time constant for all of the coils in series and see what you get.  I would not be surprised if you get a lower inductance than you think.

"If all of the coils in your motor point with the same polarity outwards, then you probably have a lot of flux cancellation between adjacent coils.  I am assuming that you measured the inductance of a sample coil with an inductance meter.  Do you know if the inductance meter can be thrown off by the high 650 ohm resistance?"

The inductance was measured on 1 coil only connected to the meter. Then measured with all 24 in series. It all calculates to be the same even though the coils are side by side in opposing polarities.

Hmm. Havnt read anything that says that I have to recalculate the inductance read with the meter by introducing the resistance value in the equation. Wouldnt the people that make the meters already have the meter do that for you if it is necessary? Like while the meter is connected to the inductor, it could first do a resistance test and sample then calculate the 'proper' inductance. But I havnt seen any dialog that different inductors with different resistances will produce inaccurate inductance reading directly related to the resistance. So are inductance meters virtually useless? ??? There are many coils, transformers and suce that have very low resistance and some with very high resistance.. I mean if your saying that to find the 'true' ideal inductance of my coils helps me any, then Im not sure how or why, because I will most likely never be working with an ideal inductor. ???

Mags

Offline Magluvin

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Re: Joule Thief 101
« Reply #2417 on: May 12, 2016, 01:37:16 AM »
What about the ideal bemf, cemf of the ideal inductor?  Why is that not an issue here? We, Brad, AC, Mags, and(the other mags) and Verpies seem to have the idea that the ideal inductor will not let current flow due to ideal cemf. What is the exact explanation that the ideal inductor will flow current when a source is applied, if we agree that the magnetic field and cemf should also be ideal in an ideal inductor? We cant pick and choose what works and what doesnt when talking ideal things. Then we are truly talking fantasy beyond what is really considered ideal.

Why is it just neglected that we have stated this many times already? Do you not agree that the cemf would be ideal also? I mean there has to be cemf if there is to be an inductance, so why is it not considered ideal and equal to the emf applied where we have a condition that no current would flow?

Mags

Offline MileHigh

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Re: Joule Thief 101
« Reply #2418 on: May 12, 2016, 01:59:30 AM »
This is what Verpies said:

<<< In an ideal inductor having a finite inductance, in series with an ideal voltage source, the current will be able to flow and it will increase linearly in time without a limit.  >>>

It makes sense that the inductance meter would do a resistance check but I thought there might be limits.  I don't know, I never played with one.  There is no such thing as "ideal CEMF."  A regular coil or an ideal coil will give you exactly the same CEMF.  This has been stated before.

I think you know the truth.

Offline Magneticitist

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Re: Joule Thief 101
« Reply #2419 on: May 12, 2016, 03:04:12 AM »
This is what Verpies said:

<<< In an ideal inductor having a finite inductance, in series with an ideal voltage source, the current will be able to flow and it will increase linearly in time without a limit.  >>>

It makes sense that the inductance meter would do a resistance check but I thought there might be limits.  I don't know, I never played with one.  There is no such thing as "ideal CEMF."  A regular coil or an ideal coil will give you exactly the same CEMF.  This has been stated before.

I think you know the truth.

I think the whole 'ideal CEMF' idea is taken from the general idea that any inductor resists the change in current. the more perfectly it does that the less it wants to return the magnetic field
when there is nothing opposing it.

when we imagine a perfect model of this we picture something that simply will not allow a current rise to begin with so long as it's something that could theoretically become charged and never dissipate over infinite time.
Some are saying this is a simple confusion where that is what would happen if there were infinite inductance but then we are left with the argument of whether or not a true measure of inductance has any relation to resistance in the real world. I just currently do not have the total math understanding to concede that the constitutive equation for the inductor and the calculation of current change over time has no relation to a unit of resistance.

Offline Magluvin

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Re: Joule Thief 101
« Reply #2420 on: May 12, 2016, 03:29:38 AM »
I think the whole 'ideal CEMF' idea is taken from the general idea that any inductor resists the change in current. the more perfectly it does that the less it wants to return the magnetic field
when there is nothing opposing it.

when we imagine a perfect model of this we picture something that simply will not allow a current rise to begin with so long as it's something that could theoretically become charged and never dissipate over infinite time.
Some are saying this is a simple confusion where that is what would happen if there were infinite inductance but then we are left with the argument of whether or not a true measure of inductance has any relation to resistance in the real world. I just currently do not have the total math understanding to concede that the constitutive equation for the inductor and the calculation of current change over time has no relation to a unit of resistance.

Wouldnt the magnet floating over the super cooled superconducting disk, block, whatever it is, be a perfect example of ideal cemf producing an equal opposing field in order for the float to happen? ;)

Mags

Offline Magluvin

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Re: Joule Thief 101
« Reply #2421 on: May 12, 2016, 03:35:11 AM »
This is what Verpies said:

<<< In an ideal inductor having a finite inductance, in series with an ideal voltage source, the current will be able to flow and it will increase linearly in time without a limit.  >>>

It makes sense that the inductance meter would do a resistance check but I thought there might be limits.  I don't know, I never played with one.  There is no such thing as "ideal CEMF."  A regular coil or an ideal coil will give you exactly the same CEMF.  This has been stated before.

I think you know the truth.

" There is no such thing as "ideal CEMF."  A regular coil or an ideal coil will give you exactly the same CEMF.  This has been stated before."

Well because it was stated doesnt mean it is fact. ;) The question would be why is the cemf not ideal? What impedes the possibility of the cemf to be ideal?


" There is no such thing as "ideal CEMF."

And, there is no such thing as an ideal inductor. ;D

Mags

Offline MileHigh

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Re: Joule Thief 101
« Reply #2422 on: May 12, 2016, 03:46:49 AM »
Go ahead and define an "ideal CEMF" yourself if you want.

No ideal inductor?  That's right, just be argumentative for the sake of being argumentative.

What do you yourself think happens when you put voltage across an ideal coil?

Offline Magluvin

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Re: Joule Thief 101
« Reply #2423 on: May 12, 2016, 05:11:53 AM »
Go ahead and define an "ideal CEMF" yourself if you want.

No ideal inductor?  That's right, just be argumentative for the sake of being argumentative.

What do you yourself think happens when you put voltage across an ideal coil?



Ok. Here is my short version of it..... Ive posted it pretty much the same for years now. Just a bit more expanded.


We all should know that when we have a charge between 2 terminals, that there are electric fields surrounding those terminals. They are in attraction, and can exist without an exchange of charge or say electrons.

So what I think is that when we go to hit the ideal on switch that the charge Im speaking of is now at the end leads of the ideal inductor. This could cause some forward vibration of the electrons in the inductor, like an atomic shift or say tension. Just a nudge, not necessarily moved from one atom to another as in current flow,could set up an initial field just in putting the electrons in a forward squeeze bump, of which that field from each winding affecting the others could be enough to have enough cemf reverse field tension to counter the input. Maybe setting up a little resonance thing. Bump and vibrate, standoff. lol

See, when we have resistance and the voltage division that it causes, then I can see that the initial field build would not be completely impeded by the cemf because we have less than 100% eff. Where the ideal inductor should be 100%efficient in all of its abilities it is defined by. To say that the ideal inductor has its shortcomings makes it less than ideal, doesnt it? And if  its cemf is not ideal, then the ideal inductor fails to be ideal. So if that is the case, where is the explanation that describes the cemf as not being ideal in an ideal inductor, and how do we 'account' for that inability of the cemf to be equal to the input in an ideal situation?

Just like I posted earlier, the magnet floating above the superconducting material, couldnt you see that as an example of what im trying to convey here? ;) Actually I think it is a near perfect example. And maybe its not just a nudge vibration of the electrons. Maybe there is some initial movement and it then has a standoff with cemf and no current is able to flow from there, just like the floating mag.

Like I also said before, we cannot lay out special rules to define the ideal inductor, especially if the rule affects the actions that the inductor is defined by.

So until there is some 'good explanation' as to why the ideal inductor cannot have an ideal cemf, then we cannot claim the cemf to not be ideal in the ideal inductor just because we eliminated all resistance.  ;)

Ok. I handover the microphone. :)


Mags

Offline MileHigh

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Re: Joule Thief 101
« Reply #2424 on: May 12, 2016, 05:32:40 AM »
The problem is that CEMF is just a measurement, it's not a tangible entity like a coil or a voltage source or a current source.  You should realize this.  It's just an electrical version of Newton's third law.

Look at this very familiar differential equation:  v = L di/dt.

Whoops, there is no resistance in that equation.  That equation is an equation for an ideal inductor and yet it is used all the time.  I suppose we are just waiting for this business to be resolved and move forward.  I am already smelling the possibility of dismal failure with no resolution to this silly impasse and the question never gets answered.  That would really be unfortunate.

Why doesn't somebody just take the lead on the question and leave Brad to stew in his own juices?  Move forward and let Brad figure it out for himself.

Offline tinman

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Re: Joule Thief 101
« Reply #2425 on: May 12, 2016, 06:48:03 AM »
The problem is that CEMF is just a measurement, it's not a tangible entity like a coil or a voltage source or a current source.  You should realize this.  It's just an electrical version of Newton's third law.

Look at this very familiar differential equation:  v = L di/dt.

Whoops, there is no resistance in that equation.  That equation is an equation for an ideal inductor and yet it is used all the time.  I suppose we are just waiting for this business to be resolved and move forward.  I am already smelling the possibility of dismal failure with no resolution to this silly impasse and the question never gets answered.  That would really be unfortunate.

Why doesn't somebody just take the lead on the question and leave Brad to stew in his own juices?  Move forward and let Brad figure it out for himself.

Only there is no t.

Your imaginary CEMF is what apposes the current rise,if it did not,the current rise time would be instant.

You will not be happy MH, unless everyone agrees with you. But like the ICE and resonance,you just cant grasp the concept of 'ideal',or what it means.

In one statement you say a voltage cannot exist across an ideal inductor while a DC current flows through it,but your question states an ideal voltage of 4 volts is across the ideal inductor while a DC current flows through it.

You have not yet provided a link to anyone that modles a circuit using only an ideal inductor-they always include a series resistor.. your simply blindly following what your books say,and are leaving 'ideal'out of it.

You need to understand what ideal means-go look up its meaning.

Brad

Offline SeaMonkey

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Re: Joule Thief 101
« Reply #2426 on: May 12, 2016, 06:53:31 AM »
Quote from: Miles Higher
Look at this very familiar differential equation:  v = L di/dt.

Whoops, there is no resistance in that equation.

Miles, are you certain that is so?  Are you certain that
resistance isn't included in its effect on something
in there? ???

Look again! :o

Offline MileHigh

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Re: Joule Thief 101
« Reply #2427 on: May 12, 2016, 06:58:48 AM »

In one statement you say a voltage cannot exist across an ideal inductor while a DC current flows through it,but your question states an ideal voltage of 4 volts is across the ideal inductor while a DC current flows through it.

Brad

You need to look at the question again and look at what my question states because it's just another bizarre moment coming from you.  You also need to grasp how an inductor works.

Offline MileHigh

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Re: Joule Thief 101
« Reply #2428 on: May 12, 2016, 06:59:43 AM »
Miles, are you certain that is so?  Are you certain that
resistance isn't included in its effect on something
in there? ???

Look again! :o

BS you bad boy.

Offline MileHigh

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Re: Joule Thief 101
« Reply #2429 on: May 12, 2016, 07:12:32 AM »
Here is the reality for you Brad:  You have myself, Poynt, Verpies and Partzman telling you how an ideal coil works and we are all in agreement.  What do you think PicoWatt is going to say?

I suggest that you hit the books until the light goes off in your head.  Then you can move on to the question.  There is no point sticking to your guns now.  The next logical move is to inform and educate yourself.