MH's ideal coil and voltage question

[MileHigh]

Anyway, I recently went back to the beginning of this thread to re-read it and I see right on page 2 of this thread, a first (and only) time poster going by "Didymus" posed the following:
I don't believe anyone ever responded to this excellent post (correct me if I am wrong, perhaps I have not yet read far enough).  Apparently, this was Didymus' first, only, and last post on this forum.

It is indeed an excellent posting.  Just look at the behavioural patterns and the answer is quite obvious.  That early in the game and Brad dismissed it as nonsense because he supposedly knew better.

Brad's very first posting, the original posting with no number, in the thread:

My answer to this question is--you cannot place an ideal voltage across an ideal inductor.
The reason being,at T=0,when the ideal voltage is placed across the ideal inductor,the current would rise instantly to a value of infinity.

It probably took about 100-200 postings to get him to budge just a little from that original position.

We can't rewrite history.

MileHigh

[tinman]

You should continue to respect his knowledge and help shutdown this site so people stop posting al that nonsense about OU!
Wake up all your wishful thinkers and let the real scientists discover better ways to get electricity.
Buy some solar panels if you want free energy.

But there not OU,and dont work so well in moon light

and help shutdown this site

So you are against this site?
You should leave,before Stephan kicks you out.


Brad

[tinman]

It is indeed an excellent posting.  Just look at the behavioural patterns and the answer is quite obvious.  That early in the game and Brad dismissed it as nonsense because he supposedly knew better.

Brad's very first posting, the original posting with no number, in the thread:

It probably took about 100-200 postings to get him to budge just a little from that original position.

We can't rewrite history.

MileHigh

And so you say that the CEMF is equal to the applied EMF,which would result in a total of 0 volts across your ideal coil that is suppose to have 4 volts across it from an ideal voltage source


Brad

[MileHigh]

I asked Poynt what he thought of your comment above,and he said--i will let MH explain that.
So could you please explain as to why you think the CEMF is identical to the EMF that created it?

Brad

Yes, there are two answers to that.  The first is the common sense answer.  If I connect a battery to a coil, the battery will impose its voltage on the coil as long as it can.  The coil is just reacting to what the battery is doing.

So the battery determines the voltage, period.  Where is there room for some kind of difference in the voltage of the battery and any imaginable voltage from the coil?   There is no room for that, they are connected together.  You would have to have a resistor between the battery and the coil for there to be any possible voltage difference between the two.

Since we know that an action produces an equal and opposite reaction, then the coil has to be reacting equally and opposite to the battery.  Same thing for a resistor.

So even though the battery is imposing its voltage on the coil, you need to be able to shift your perspective and go "inside" the coil and realize that the coil is pushing back with the same CEMF.

You can take a ridiculously simple example from the physical world:  If you are balancing a water jug on your head, then your head is pushing up with the same force as the water jug is pushing down.  It is as simple as that.

Or you just have enough common sense to realize the applied EMF and the CEMF are identical without even having to think about it.

Now if all of this stuff is elusive to you, then KVL to the rescue:

Kirchhoff's voltage law (KVL) The sum of all the voltages around the loop is equal to zero. This law is also called Kirchhoff's second law, Kirchhoff's loop (or mesh) rule, and Kirchhoff's second rule.

The applied EMF and the CEMF from the coil must add up to zero.  Therefore, the CEMF must be equal and opposite to the EMF.

Just memorize it if it does not come naturally to you.

[MileHigh]

And so you say that the CEMF is equal to the applied EMF,which would result in a total of 0 volts across your ideal coil that is suppose to have 4 volts across it from an ideal voltage source

Brad

This is the point where the seasoned violinist in the London Symphony Orchestra smashes his Stradivarius against the wall in a moment of extreme loss of composure.

The highest price paid for a Stradivarius violin is $16 million (£9.5 million). A rare viola made by the Italian artisan Antonio Stradivari in 1719 that will be sold by Sotheby's in a sealed bid auction in June is valued at $45 million (£27 million).