MH's ideal coil and voltage question

[tinman]

<<< So,the current either rises instantly,or the current rise time is infinite,which means there is no current flowing through the ideal coil.  >>>

Sorry but I have to lol, when the "answer" is two completely contradictory answers.

Exactly MH.
As i said,you did not think about your question to well when you added ideals to it.
It is also the reason i stated that an ideal voltage cannot be placed across an ideal inductor.
You did see the word conundrum attached to that post-along with several other posts--didnt you?.

Your question cannot be answered,as it is a contradiction to it self.
You stated as well that there is no time constant. What dose that mean?--dose the current rise instantly,or is the L/R time constant infinite?.


Brad

[tinman]

@ MH

for many years Poynt has told me that a sim can simulate any real world circuit. Poynt also knows how much i hate the use of sim's when dealing with real world circuit's. But time after time ,Poynt has shown me that the sim has been successful 100% of the time in replicating anything i (and others) have built,and has come to more exacting results than i could obtain on the bench with real world devices.

Poynt has just stated that your circuit as defined cannot be simulated,and so your circuit dose not represent a real world device.

But i would like to continue with this discussion ,as it has really made me (and others here)think of what the outcome of your defined circuit would be.

At this point in time,i am sticking to my answers given-both the real world answer-->you cannot place an ideal voltage across an ideal inductor,and also my theoretical answer,being the current would rise instantly,to an infinite value.
The reason for my theoretical answer is because of the resistance value of zero when calculating the L/R time constant.
I have found no math that allows for any value to be divided by zero without the answer being infinite. If the current rise time is infinite,then there is no rise in current as far as the inductor side of it go's. This means that there is no inductor. But as there is an ideal resulting in a zero value of resistance,the ideal voltage is now placed across a dead short--the big conundrum of the whole question using your ideal values.

And so my answer of an instant current rise of an infinite value.


Brad

[tinman]

My blown universe post was a bit of a ruse. In fact it implied the opposite of what would theoretically happen, that is, "nothing".

So you are saying that at T=0--the instant the ideal voltage is placed across the ideal inductor,nothing would happen?--no voltage would appear across the ideal inductor?.


Brad

[MileHigh]

<<< Poynt has just stated that your circuit as defined cannot be simulated,and so your circuit dose not represent a real world device. >>>

Of course it can be simulated.  To my surprise in this case he has to add a resistor.  We have seen him add little phantom resistors many times in the past to get the simulator to run so ultimately there is no real surprise.

The place to simulate this setup is in your head, like I explained before.  Then there are no issues.  I am attaching the "short answer that solves everything" again to this posting.

[MileHigh]

Brad:

How about this:  Take the identical question and add a 0.00000000001 ohm resistor in series with the 5 Henry ideal coil.  Now you have a real-world coil.

Can you answer the question now?  If you answer that properly then as far as I am concerned your answer will be perfectly legitimate.

MileHigh