MH's ideal coil and voltage question

[tinman]

Some things to consider.

An ideal voltage source is a voltage source that supplies constant voltage to a circuit despite the current which the circuit draws.
This means that despite the resistance which a load may be in a circuit, the source will still provide constant and steady voltage.
An ideal voltage source has the following characterstic that allows it to act as a 100% efficient source of voltage: it has zero internal resistance.

An "ideal inductor" has inductance, but no resistance or capacitance, and does not dissipate or radiate energy.

Why can a voltage not exist across a shorted ideal inductor that has current flowing through it>
Because V=IxR,and R=0
The polarity of the voltage across an inductor is determined by-the positive being the terminal the current is flowing into,and negative being the terminal the current is flowing out from. With a shorted ideal inductor,there are no terminals to measure the voltage across,and the current flowing through that ideal inductor is the same at any two points of that inductor.


Brad

[poynt99]

I think use of the term "shorted" when referring to an ideal inductor is not good nor accurate nomenclature.

An ideal inductor simply has zero series resistance. It is not "shorted" in any way, and will not present itself as a "short" if/when a voltage source (ideal or not) is connected across it.

[tinman]

I think use of the term "shorted" when referring to an ideal inductor is not good nor accurate nomenclature.

An ideal inductor simply has zero series resistance. It is not "shorted" in any way, and will not present itself as a "short" if/when a voltage source (ideal or not) is connected across it.

You need to think a little beyond what you are Poynt,and draw the circuit as MH said i should,
I have provided the definitions of the ideal voltage from an ideal voltage source,and an ideal inductor.

If an ideal inductor is shorted,so as it becomes an endless loop,can a voltage be measured anywhere across any two points of that(now looped) ideal inductor while a current is flowing through it?.


Brad

[tinman]

 author=webby1 link=topic=16589.msg484135#msg484135 date=1463187555]

There could be voltage that you can not measure or interact with because all the way around the loop the voltage would be uniform,, so current flow but no way to measure the voltage.

It is good to see some one is thinking here.

Part of what I am thinking over is that there is a nexus event that can and is described from several views of the same event.

A paradox

No voltage can be measured across a shorted(looped) ideal inductor,even though current may be flowing through that inductor,as V=IxR stands,and the very reason that current can continue to flow through an ideal inductor is because there is no resistance,and hence the fact that an ideal inductor dose not dissipate any power.


The ideal voltage source that supplies our ideal voltage,by true definition has no internal resistance. As it has no internal resistance,then it too will not dissipate any power by way of an internal resistance. Having no internal resistance,the current flow is in no way impeded ,an so that is what makes it an !ideal! voltage source.


At T=0,the ideal voltage source is connected to the ideal inductor-->what have you just done?


Brad


Brad

[poynt99]

You need to think a little beyond what you are Poynt,and draw the circuit as MH said i should,
I have provided the definitions of the ideal voltage from an ideal voltage source,and an ideal inductor.

If an ideal inductor is shorted,so as it becomes an endless loop,can a voltage be measured anywhere across any two points of that(now looped) ideal inductor while a current is flowing through it?.


Brad

What is there that is beyond a voltage source and an inductor in series/parallel? I can draw it out in my head, what am I missing?

Let's throw in an ideal switch as well. What happens when the switch closes?

The second part of your question sounds like Faraday induction with the coil shorted.