Joule Thief 101

[tinman]

The problem is that CEMF is just a measurement, it's not a tangible entity like a coil or a voltage source or a current source.  You should realize this.  It's just an electrical version of Newton's third law.

Look at this very familiar differential equation:  v = L di/dt.

Whoops, there is no resistance in that equation.  That equation is an equation for an ideal inductor and yet it is used all the time.  I suppose we are just waiting for this business to be resolved and move forward.  I am already smelling the possibility of dismal failure with no resolution to this silly impasse and the question never gets answered.  That would really be unfortunate.

Why doesn't somebody just take the lead on the question and leave Brad to stew in his own juices?  Move forward and let Brad figure it out for himself.

Only there is no t.

Your imaginary CEMF is what apposes the current rise,if it did not,the current rise time would be instant.

You will not be happy MH, unless everyone agrees with you. But like the ICE and resonance,you just cant grasp the concept of 'ideal',or what it means.

In one statement you say a voltage cannot exist across an ideal inductor while a DC current flows through it,but your question states an ideal voltage of 4 volts is across the ideal inductor while a DC current flows through it.

You have not yet provided a link to anyone that modles a circuit using only an ideal inductor-they always include a series resistor.. your simply blindly following what your books say,and are leaving 'ideal'out of it.

You need to understand what ideal means-go look up its meaning.

Brad

[SeaMonkey]

Look at this very familiar differential equation:  v = L di/dt.

Whoops, there is no resistance in that equation.

Miles, are you certain that is so?  Are you certain that
resistance isn't included in its effect on something
in there?

Look again!

[MileHigh]

In one statement you say a voltage cannot exist across an ideal inductor while a DC current flows through it,but your question states an ideal voltage of 4 volts is across the ideal inductor while a DC current flows through it.

Brad

You need to look at the question again and look at what my question states because it's just another bizarre moment coming from you.  You also need to grasp how an inductor works.

[MileHigh]

Miles, are you certain that is so?  Are you certain that
resistance isn't included in its effect on something
in there?

Look again!

BS you bad boy.

[MileHigh]

Here is the reality for you Brad:  You have myself, Poynt, Verpies and Partzman telling you how an ideal coil works and we are all in agreement.  What do you think PicoWatt is going to say?

I suggest that you hit the books until the light goes off in your head.  Then you can move on to the question.  There is no point sticking to your guns now.  The next logical move is to inform and educate yourself.