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Author Topic: MH's ideal coil and voltage question  (Read 477819 times)

partzman

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Re: MH's ideal coil and voltage question
« Reply #1590 on: July 07, 2016, 04:09:31 PM »
Has anyone here read Miles Mathis?   Here is a quote from his paper "Alternating Current and Inductance".

"This also explains inductance.  The whole idea of inductance is something they invented because theydon't have a real charge field.  Without inductance, they can't explain why current moves in AC, as above, so they come up with inductance as the explanation.  The textbook definition of inductance is a voltage produced by a changing current.  That is odd beyond odd, since they previously defined current as produced by voltage.   So they are telling you that voltage causes current, and changing current causes voltage.  I think you can see they have gone circular.  The effect cannot cause the cause.
 
Once you have a real charge field creating your field of initial potentials—both electric and magnetic—you don't need inductance.   Mutual inductance is easily explained because the ambient charge field links all local charge fields.  And self-inductance is just a ghost.  Once you understand how the field really works, you don't need it.  It isn't inductance that is the cause of energy transfers, it is the charge field.
 
All this goes back to initial confusion by Faraday, which has persisted to this day.   Faraday didn't recognize the existence of a real charge field, composed of real particles like photons.  Nobody at the time did.   Therefore, when he saw these effects being produced, he couldn't show a direct cause. Instead of being created or produced, they had to be induced.   Something that is induced is produced indirectly, by unknown means.  Think of the difference between deduction and induction in philosophy.
Deduction is supposed to be a straight line of logical cause and effect, while induction can be much less rigorous.  It is much the same here. The word induction was not chosen by accident.  It was a sort of admission that no mechanics could be pointed to.  Faraday then created some lines of potential or force, but they were back-engineered from the motions.  No kinematics was involved, and Faraday admitted it.  How could he not?  While it is not surprising that Faraday did what he did at the time, it is quite surprising we have improved on it so little in almost two centuries.  We now have mountains of data pointing directly at a   real charge field composed of real particles, but we still teach electrical engineering based on these old outdated ideas. It would be like medical schools still teaching leechcraft."

pm

 

picowatt

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Re: MH's ideal coil and voltage question
« Reply #1591 on: July 07, 2016, 04:17:34 PM »
No Poynt,i dont think i have missed the boat at all.

Let me ask you this,and in an ideal way.
We have two identical rocket engines strapped to two identical carts. Each rocket engine can produce 1000LBs of thrust. The two are put nose to nose,and they are fired up. Every time rocket engine 1 is throttled up to produce an extra 100 LBs of thrust,rocket engine number 2 also matches that increase in thrust. At no point in time will rocket engine number 1 move rocket engine number 2,as long as rocket engine number 2 matches the thrust of rocket engine number 1--it is a stale mate,and no motion takes place.

For this analogy to work, lets tie the carts together so they act as a single cart and lets point the rocket engines' thrusts away from each other so they oppose.  Engine #1 has a fixed and continuous thrust (EMF).  Engine #2 has an identical thrust that can be turned on or off (CEMF).  A sensor and control mechanism is used to determine the acceleration (rate of change) of the cart in the direction determined by engine #1's thrust.  We have set the desired acceleration rate to 800 feet per second .

Engine #1 fires and the cart accelerates.

1.  When the cart's acceleration reaches 800 feet per second, engine #2 fires

2.  When engine #2 fires, the cart's acceleration decreases

3.  When the cart's acceleration becomes less than 800 feet per second, engine #2 is cutoff

4.  When engine #2 is cutoff, the cart's acceleration increases (return to 1, loop forever)

Again, this is a step wise description.  If engine #2 could respond instantaneously, and the time between steps were made infinitely small, there would be a smooth and continuous acceleration of the cart at a rate of 800 feet per second in the desired direction.

PW

partzman

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Re: MH's ideal coil and voltage question
« Reply #1592 on: July 07, 2016, 05:00:52 PM »
Gyrator-capacitor modeling of inductors and transformers can yield quite accurate simulations of complex electromagnetic devices. I've attached a simulation of a co-planar 3-winding transformer with gaps that has complex couplings and leakage inductances. 

In some ways, the application of gyrators for magnetic problems are easier to understand with their magnetic and electric equivalencies.

pm

picowatt

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Re: MH's ideal coil and voltage question
« Reply #1593 on: July 07, 2016, 05:19:24 PM »
Gyrator-capacitor modeling of inductors and transformers can yield quite accurate simulations of complex electromagnetic devices. I've attached a simulation of a co-planar 3-winding transformer with gaps that has complex couplings and leakage inductances. 

In some ways, the application of gyrators for magnetic problems are easier to understand with their magnetic and electric equivalencies.

pm

Partzman,

My only experience with gyrators is with respect to fixed and variable Q simulated inductors built using opamps, resistors, and capacitors as used in analog circuits.

Using them to simulate transformer design is, well, "tip of my hat to you" stuff!

Looks very interesting...

PW

partzman

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Re: MH's ideal coil and voltage question
« Reply #1594 on: July 07, 2016, 09:50:49 PM »
Partzman,

My only experience with gyrators is with respect to fixed and variable Q simulated inductors built using opamps, resistors, and capacitors as used in analog circuits.

Using them to simulate transformer design is, well, "tip of my hat to you" stuff!

Looks very interesting...

PW


Thank you PW. 

Off topic but many years ago I designed and marketed a digital tuner for pianos, stringed instruments, etc, that used a very high Q gyrator/capacitance simulated inductor in series resonance that allowed measuring over three octaves with one setting. This created an electronic capability of "stretch tuning" the overtones of a stringed instrument in the same manner as a skilled professional tuner. The accuracy was 1 cent with 100 cents/semitone.

Also off topic but I read the comments about solid state vs tubes so I assume some here are pickers and/or audiophiles. I researched the differences nearly fifty years ago as best one could with a single channel kit scope, and determined the main difference was the output impedance or damping factors. I found tube outputs to be soft or poorly regulated with the changes in speaker impedance over a given frequency range, where s/s was highly regulated with high damping factors. By using a combo of negative voltage and current feedback in a s/s bipolar power amp, one can approach the ideal tube type output impedance tracking which yields the fat, warm tube sound. Other factors played a role as well like depletion mode j-fets in preamps, passive tone networks,  and phasing the output so the attack transients from a string pushed the cone forward, etc.

With today's mosfet power devices and engineering tools, some really good sounding amps could be built.

pm

poynt99

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Re: MH's ideal coil and voltage question
« Reply #1595 on: July 07, 2016, 11:13:22 PM »
Also off topic but I read the comments about solid state vs tubes so I assume some here are pickers and/or audiophiles. I researched the differences nearly fifty years ago as best one could with a single channel kit scope, and determined the main difference was the output impedance or damping factors. I found tube outputs to be soft or poorly regulated with the changes in speaker impedance over a given frequency range, where s/s was highly regulated with high damping factors. By using a combo of negative voltage and current feedback in a s/s bipolar power amp, one can approach the ideal tube type output impedance tracking which yields the fat, warm tube sound. Other factors played a role as well like depletion mode j-fets in preamps, passive tone networks,  and phasing the output so the attack transients from a string pushed the cone forward, etc.

 ;)

Aren't all JFETs depletion mode?

I prefer enhancement mode MOSFETs for my pre-amp designs, hi-fi and guitar/bass.
 

minnie

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Re: MH's ideal coil and voltage question
« Reply #1596 on: July 08, 2016, 12:13:54 AM »



 Is it sort of near field coupling, or am I barking up the wrong tree?
      John.

tinman

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Re: MH's ideal coil and voltage question
« Reply #1597 on: July 08, 2016, 01:24:53 AM »
For this analogy to work, lets tie the carts together so they act as a single cart and lets point the rocket engines' thrusts away from each other so they oppose.  Engine #1 has a fixed and continuous thrust (EMF).  Engine #2 has an identical thrust that can be turned on or off (CEMF).  A sensor and control mechanism is used to determine the acceleration (rate of change) of the cart in the direction determined by engine #1's thrust.  We have set the desired acceleration rate to 800 feet per second .

Engine #1 fires and the cart accelerates.

1.  When the cart's acceleration reaches 800 feet per second, engine #2 fires

2.  When engine #2 fires, the cart's acceleration decreases

3.  When the cart's acceleration becomes less than 800 feet per second, engine #2 is cutoff

4.  When engine #2 is cutoff, the cart's acceleration increases (return to 1, loop forever)

Again, this is a step wise description.  If engine #2 could respond instantaneously, and the time between steps were made infinitely small, there would be a smooth and continuous acceleration of the cart at a rate of 800 feet per second in the desired direction.

PW

And there is the problem PW.
Engine 2s thrust dose not just start only when engine 1 has reached a point of acceleration of 800 feet per second,nor dose engine 2s thrust simply switch off when engine 1s acceleration drops below 800 feet per second. Engine 2s thrust matches that of engine 1 at every instant,and so there is no motion between the two.
I see the same thing with the EMF induced current,and the CEMF induced counter current,where every change made by the forward current is counteracted by the CEMF induced reverse current.
Why dose this action/reaction have to start only when a rate of change has reached a level of 800mA per second?
The value in question here,is the 800mA per second,and it seems that your self and Poynt keep using this very value to justify the value in question it self.
This feed back system i believe should represent a situation where if you push against a concrete wall,the concrete wall will push back just as hard at the very same time,and the net result is no motion. The way i see you explaining thing's,is that some how,the person is able to move the concrete wall,even though the concrete wall is pushing back just as hard.

The ideal coil becomes a power source it self in this case,and it matches that which was induced into it,only with opposition.

Anyway,i am going to leave it at that,as i dont think it is going to go anywhere,when the value in question is being used to confirm the value in question,when the conversation is about that very value it self.


Brad

picowatt

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Re: MH's ideal coil and voltage question
« Reply #1598 on: July 08, 2016, 03:22:07 AM »
And there is the problem PW.
Engine 2s thrust dose not just start only when engine 1 has reached a point of acceleration of 800 feet per second,nor dose engine 2s thrust simply switch off when engine 1s acceleration drops below 800 feet per second.

First, its an analogy, but as I have modified it, it is a very close to describing the action of an inductor.  It has the same negative feedback and just like the inductor, and the step wise description has no CEMF, or counter thrust. until the rate of change reaches the desired rate.  As stated over and over, it is only being _described_ to you in a step wise fashion.  It is actually a smooth and continuous process.  As stated in the analogy, try to envision those steps being separated by an infinitely small amount of time and engine #2 having instantaneous response.

Quote

Engine 2s thrust matches that of engine 1 at every instant,and so there is no motion between the two.

When does this happen, in either the analogy or the inductor?

If the two thrusts are equal, acceleration decreases.  If acceleration is less than 800f/s, engine#2 fires again.

This is the same as what happens when CEMF=EMF which causes the current flows rate of change to decrease.  But when the rate of change is less than .8A/s, the CEMF is no longer equal to the EMF so the rate of change again increases.  The rocket engine analogy is a very good example of a similar feedback mechanism.   

Quote
I see the same thing with the EMF induced current,and the CEMF induced counter current,where every change made by the forward current is counteracted by the CEMF induced reverse current.

You are not working with an inductor.  You are working with an inductor in series with a reaistor with a capacitor connected across the two.

Quote
Why dose this action/reaction have to start only when a rate of change has reached a level of 800mA per second?

It does not "only start" when the .8A/s is reached.  .8A/s is the rate of change that produces a CEMF of 4 volts in a 5H inductor.  It is the rate of change that current is limited to when 4 volts is placed across a 5H inductor. 

Quote
The value in question here,is the 800mA per second,and it seems that your self and Poynt keep using this very value to justify the value in question it self.

Seems like the there is much more "in question"..

Perhaps if you were to study the basic units of the Volt, Ampere, Ohm, Farad, and Henry, this would be more clear to you.

The definition of a Henry specifies what value the generated CEMF will be for a given value of inductance with a given rate of change of current flowing thru that inductance (actually, it is with regard to the rate of change of the magnetic flux.  However, in an inductor, the current flowing thru it creates the magnetic field and the rate of change of the current flow is also the same as the rate of change of the magnetic field created by that current flow).

One Henry will generate a CEMF of 1 volt when the current flowing thru it is changing at 1A/s.

A 5H inductor will generate a CEMF of 4 volts when di=.8A/s. 

A 5H inductor will generate a CEMF of 5volts when di=1A/s.  So, if a 5H inductor is connected across a 5 volt source, current flow thru the inductor will rise at 1A/s.

Put 10volts across a 5H inductor and current will rise at 2A/s, because a 5H inductor with current rising at 2A/s will generate a CEMF of 10Volts.

The CEMF is what limits the current flow's rate of change, and the CEMF is well defined for a given inductance and rate of change.

It is somewhat similar to the defined relationship of 1 volt across 1ohm causing 1amp to flow.

Quote
This feed back system i believe should represent a situation where if you push against a concrete wall,the concrete wall will push back just as hard at the very same time,and the net result is no motion. The way i see you explaining thing's,is that some how,the person is able to move the concrete wall,even though the concrete wall is pushing back just as hard.

I am not explaining it that way...

It pushes back only as hard as necessary to limit the rate of change to .8A/s.

Perhaps you are just not familiar with negative feedback.  The rocket engine analogy was a very good example of a negative feedback loop.  As I have stated over and over, although described in a step wise fashion, it is a smooth and continuous process.

Quote
 

The ideal coil becomes a power source it self in this case,and it matches that which was induced into it,only with opposition.

And that opposition only allows the inductor's current to change at a rate of .8A/s (4V across 5H)

Quote

Anyway,i am going to leave it at that,as i dont think it is going to go anywhere,when the value in question is being used to confirm the value in question,when the conversation is about that very value it self.

It is indeed obvious that it is not going anywhere...

Regarding the "value" you are so concerned with, perhaps time spent studying the definitions of the most basic units used in electronics would be of help (Volt, Amp, Ohm, Farad, and Henry).

PW
« Last Edit: July 08, 2016, 06:10:00 AM by picowatt »

poynt99

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Re: MH's ideal coil and voltage question
« Reply #1599 on: July 08, 2016, 02:18:15 PM »
The feedback system,, well that would have an oscillation,, an extremely small amplitude and high frequency sure,, but an oscillation anyway, and as such invalidates the results.
It is clear that many can not get their heads around negative feedback. There would be no oscillation, at any frequency or amplitude.

Imagine a centrifugal clutch. In a way it can be thought of as a rpm regulator. At a certain rpm, the clutch, due to the centrifugal force engages, and if we anchor the axle so that it can not move, this is obviously going to cause drag on the motor. The harder the motor tries to turn the axle, the more the clutch engages (if the rpm increases), etc. There is no oscillation there.

It is a very similar case with the inductor and the feedback mechanism, except that process begins the instant even minute currents begin to flow. It is an instantaneous reaction that limits the rate of rise. Can you see that the current would rise very quickly upon connection? Can you also see that the cemf would be induced instantly in conjunction with that current?

poynt99

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Re: MH's ideal coil and voltage question
« Reply #1600 on: July 08, 2016, 02:47:43 PM »
And what does any of that have to do with the present discussion?

minnie

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Re: MH's ideal coil and voltage question
« Reply #1601 on: July 08, 2016, 03:41:43 PM »



  Take two identical batteries,call on EMF,the other CEMF. Put a resistor across
 battery EMF,current flows,now introduce battery CEMF, nothing changes,current
 still flows.
    It has to be the rate of change that makes the whole thing tick.
            John.

partzman

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Re: MH's ideal coil and voltage question
« Reply #1602 on: July 08, 2016, 04:17:30 PM »
;)

Aren't all JFETs depletion mode?

Yes they are, but it might be an interesting experiment to see what oscillations might exist at the threshold of forward conduction in the pn gate to source junction!

Quote

I prefer enhancement mode MOSFETs for my pre-amp designs, hi-fi and guitar/bass.

Yes I can understand why. Higher operating voltage for all the class A preamps would improve the signal to noise ratio with the higher gains that could be achieved plus the wider dynamic range. The jfets used back when had a Vds of ~30v so the signal swings were puny compared to say a 12AX7A or 7025.

I'm sure you are familiar with Crown's technology of using a split power supply in the output section where the load is connected between the center tap of the supplies and ground, and the + and - terminals are driven by complimentary bipolars or mosfets. IOW, the entire high voltage/current supply swings at the audio rate. Unaware of Crown back then, I developed the same technology that I sat on for years before building a company around the idea. The design symmetry allowed easy implementation of current and voltage feedback plus control points for prevention of saturation, soft start, quiescent bias, etc.

pm

picowatt

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Re: MH's ideal coil and voltage question
« Reply #1603 on: July 08, 2016, 07:01:34 PM »
Yes I can understand why. Higher operating voltage for all the class A preamps would improve the signal to noise ratio with the higher gains that could be achieved plus the wider dynamic range.


Dynamic range?  In a guitar amplifier?  Surely you jest...

Back in the day when audiophiles were trying to reconcile the difference between tubes and solid state, or trying to discern the difference between two amplifier's with similar THD but having a different "sound", listening to the attributes of various tone arms and cartridges, and then later on doing A-B comparisons between analog and early digital, guitar players were doing the "crank 'em all up to 10" maneuver on Marshalls and the like. 

Have you ever looked at the waveforms coming out of a Marshall while it's cranking away at ear deafening levels?

Besides clipping just about every stage in the Marshall and saturating the OT, at the levels being played, feedback from the microphonics generated as tubes were rattled to the brink and even the guitar itself, were all contained within an electronic and acoustic feedback loop that was part of a very loud "harmonic generator" or guitar "sound generator".

And if you happened to have a very loud guitar "sound generator" ("amplifier" being a misnomer...) that just did not generate enough harmonics, or was not "edgey" or "fuzzy" enough for you, no worries, all manner of pedals could fix ya' up.

To the woe of every frustrated sound man trying to get a decent live mix and having to deal with stage wash from the axes bleedin' into everything, the words "can you turn it down a bit?" were repeated as if a mantra.

So, with tongue in cheek, and no offense intended toward any guitar players out there, amplifying the sound of the "guitar" has rarely been the desired intention of a guitar "amplifier", but rather it is to use that guitar in the feedback loop of an ear deafeningly loud guitar "sound generator" capable of producing all manner of harmonics.

My apologies to all, I digress...

PW

poynt99

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Re: MH's ideal coil and voltage question
« Reply #1604 on: July 08, 2016, 08:08:50 PM »
Dynamic range?  In a guitar amplifier?  Surely you jest...
For audio "Hi-Fi", yes of course. For the "clean" channel of a guitar or bass amp, yes to a degree.

Quote
So, with tongue in cheek, and no offense intended toward any guitar players out there, amplifying the sound of the "guitar" has rarely been the desired intention of a guitar "amplifier", but rather it is to use that guitar in the feedback loop of an ear deafeningly loud guitar "sound generator" capable of producing all manner of harmonics.
The amp is certainly 50% of the guitarist's "tone".

Pre/Pwr tubes and OPT's are obsolete, as I hope to prove in the near future.