MH's ideal coil and voltage question

[tinman]

Zero current means no load. So we have an infinite load, i.e. an "open" circuit.

Ok,im going to need help understanding this Poynt

The zero current meaning no load is no problem,but having an infinite load(a load of infinite proportions),would this not require a current flow of infinite magnitude?,and we have no current flow.


Brad

[poynt99]

MH,

For your test (13s of a few different voltages), the different voltages have no affect on the outcome.

So the question could have been asked with one voltage and still have the same answer, correct?

I did the simulation with 0.0000000001f (femto) Ohms, which is very very small, and ran it for 100s, far exceeding the limit of your test. The current stayed flat at 0A for the full 100s. Needless to say the voltage across the coil also remained at 4V for the entire 100s.

I think we can conclude from these results that my answer is correct.

[tinman]

I am going to have to assume that you don't understand the question.  Before t=0 the voltage source and the coil are disconnected.  The only reason for putting it that way is to implicitly establish that the current through the coil is zero at the start of the test.  At t=0 you then have a 4-volt source connected to a 5-Henry inductor, and then the voltage varies in time as described.

When it is reworded as above, is it clear now?

Im going to have to correct that MH.
At T=0,an ideal voltage of 4 volts is placed across an ideal inductor of 5 Henrys for 3 seconds. This is how your question reads.

To quote again,An ideal voltage source is a two-terminal device that maintains a fixed voltage drop across its terminals. It is often used as a mathematical abstraction that simplifies the analysis of real electric circuits.

Brad

[tinman]

MH,

For your test (13s of a few different voltages), the different voltages have no affect on the outcome.

So the question could have been asked with one voltage and still have the same answer, correct?

I did the simulation with 0.0000000001f (femto) Ohms, which is very very small, and ran it for 100s, far exceeding the limit of your test. The current stayed flat at 0A for the full 100s. Needless to say the voltage across the coil also remained at 4V for the entire 100s.

I think we can conclude from these results that my answer is correct.

Poynt

Thank you for your time on this,i am really enjoying this topic.
But i have to get some sleep--work in 3 hour time

I hope we can look into this further together,along with anyone else that is interested.


Cheers

Brad

[poynt99]

Ok,im going to need help understanding this Poynt

The zero current meaning no load is no problem,but having an infinite load(a load of infinite proportions),would this not require a current flow of infinite magnitude?,and we have no current flow.


Brad

Don't get too hung up on my use of the term "infinite load". In electronics when we say that we mean an "open circuit", not a "short circuit". I know it seems counter intuitive. If we mean to say a "short", we say "short, "short circuit" or "zero Ohm" load.