MH's ideal coil and voltage question

[tinman]

I am not attacking you.  In fact the "you" in my posting refers to all those that "don't believe" that an ideal voltage source can vary with respect to time.  Like it or not, many people would find just arguing the issue to be strange.  It's kind of a mom and apple pie issue and you are of the group saying that you are not allowed to put ice cream on your apple pie.  It just makes no sense.

I am not going to address all of the drama in your posting about me nor all of the drama you raise about the question itself.  There is no need for all of this, truly.  Brad and others are supposed to be trying to answer a simple question and understand all of concepts and the related issues.  As far as I am concerned this whole thing should have happened six years ago.

You made reference to a question of yours that was ignored.  I don't see a question in post #454.  That posting is really hard to digest, BTW.  I went back a few more pages and did not see anything so I suppose you are taking about your post #454.  If you can tell me what the question is I will try to answer it.

MileHigh

The only reason you are saying !Brad! and others are !!trying!! to answer the question,is because we dont agree with you,and this is something you do all the time.
If you think you are correct beyond being able to be incorrect,then that is nothing more than your own arrogance shining through--and this go's for any of the EE guys that think they have all the answers.

You are dealing with ideal that have not,and cannot be delt with. But you feel that you have all the answers sitting in your hand,and they are correct beyond doubt-->bullshit.

Here is one big flaw between the EE guys that think they all agree with one another,and the answer is nailed down solid.

Quote MH-->An ideal voltage source does not "contain energy" and likewise an ideal short does not "contain energy.
Im not sure what planet MH is on there?.

Quote Poynt-->The energy in the inductor does not "disappear", some is returned to the source during that period.

So we know that the source is the ideal voltage source,and being that Poynt says that the energy in the inductor is returned to the source,that must mean that the ideal voltage source is what contains that returned energy--but MH says that the ideal voltage source dose not conatin energy???

So we see here that the two guys that say that each other agree with each others theory ,dont seem to agree on what one of the two components in this circuit can do.

And as far as MHs comment about the ideal short not containing energy,well when it is taken !in! context as it should be,and that being the discussion of the ideal coil having an ideal short across it,then it dose indeed contain energy.
An ideal short is a short with no resistance,and our ideal coil has no resistance,and so when that ideal coil is a continual loop(shorted across it's terminal's),then it is an ideal short--as verpies showed it to be.

So you can see here that there is a discrepancy between the two that think they have the answer nailed down,and also the fact that MH is not the guru that he claims to be here.
How he ever came up with--an ideal voltage source dose not contain energy,is beyond me.


Brad

[tinman]

@ Poynt

As you believe that MH could answer his question correctly,and following his statement-An ideal voltage source does not "contain energy"
I ask you once again--how is the energy dissipated in the ideal inductor loop during the 0 volt period,so as the negative 3 volt period can start inducing a current flow in the opposite direction to that of the current already flowing?. The energy stored in the inductor loop during the 0 volt period is in opposition to that of what the ideal voltage source wants to induce,and so it must be removed before the next phase can start.

So either you are incorrect,and the energy in the inductor is not returned to the source,or MH is incorrect,and the ideal voltage source can contain this returned energy.

If you are incorrect,then we have not yet derived at a correct conclusion to this question of MHs.

If MH is incorrect,then how is it possible that he could have answered his question correctly?--how would he have explained as to where the stored energy in the inductor went before the next part of the cycle started?.


Brad

[tinman]

           John.
    We must thank the likes of MH. poynt etc. for their patience in inching us along.

wattsup,tinman and me, what I've learned is if you want to do electronics
   you've got to go to college and start from DAY ONE and really pay attention.
    I'm managing to get a bit but only by constantly referring to very basic
   tutorials.

You mean go for your Indoctrination.
You seen a perfect example of how !wrong! you can be taught--even at the best of the best of them--MIT.
One of the best physics teachers of all time's-Walter Lewin,got it wrong.
The best of the best teach them selves--Nikola Tesla.

Brad

[tinman]

It helped Wattsup to notice that he needs to be more careful with his words.
These are technical posts and every word matters. Making mental shortcuts is sometimes funny but most often it requires "secret decoder rings" from the reader.  Those are not good habits for technical communication.

So now we have established that an ideal voltage source merely needs to have:
- zero internal resistance
- zero internal reactance
- an output voltage that is not affected by the load

...but it does not need to output a constant output voltage all the time, and it can be even an ideal alternating voltage source.

We can consider the direction of the current flowing through this ideal voltage source.

So we have 2 variables and each one can have 2 states.  This gives us 4 combinations.

Of course this is again the 4-quadrant operation, where:
- 2 combinations result in energy flowing from the voltage source to the load
- 2 other combinations result in energy flowing from the load to the voltage source

Can you enumerate which ones?

Brad will like this:
The current can flow in two directions through the voltage source and the voltage presented by this voltage source can have two polarities, too

.

Well of course it can,but it cant have both at the same time.
Current cant flow in both directions at the same time,and the two voltage polarities cannot exist across the terminals at the same time.
But it would seem that the current can flow out and into this ideal voltage source at the same time???--well as far as Poynt is concerned. And MH--well ,he states that the ideal voltage source cannot contain energy at all. So,in MHs case, i have no idea as to where the energy comes from to induce the current flow MH calculated through his ideal circuit


Brad

[MileHigh]

Brad:

The simple fact is that you have trouble with abstract concepts.  An example is an ideal voltage source varying in time, you still refuse to believe that.  In the more difficult version of the question the ideal voltage source varies in time.  You need to move on with respect to the ideal voltage source business and just accept it.

An inductor can store energy.  A capacitor can store energy.  A battery can store energy.  But an ideal voltage source does not "store energy."  "How many Joules are in that ideal voltage source?" is a question that makes no sense.  An ideal voltage source is a potentially unlimited source of power.  It is simply "power on tap" and it doesn't make sense to think about it storing energy.

If an inductor returns a finite amount of energy back to an ideal voltage source then that energy is not to be "found inside" the ideal voltage source.  The concept of an ideal short "containing energy" is simply ridiculous.

It's like a jigsaw puzzle were you want to force pieces of the jigsaw puzzle together that don't fit because you said something and the only way to backup your statement is to force some concepts together that don't fit.  It's related to your issue about refusing to accept that you are wrong.

It's time for the discussion to move forward.  What is the complete current waveform and more importantly what are the concepts that explain the current waveform?  The only part of the question that you have answered so far is the fact that the current doesn't change when the ideal voltage source outputs zero volts.  The clues to answering the full question are in this thread.

You have to understand what is taking place in the circuit and why it does what it does if you are going to understand and appreciate the harder version of the question that has already been answered.

MileHigh