Joule Thief 101

[MileHigh]

That posting is just sad Brad.  It shows how you are so limited in your understanding and how your powers of conceptualization are so weak that you would think that your response to my posting is legitimate.  Instead of trying to solve the easier question as is and being puzzled and intrigued by the answer to the more difficult question and how I arrived at it it, you are the "problem student" that can't understand the question and objects to the wording in the question.  It's just sad.

[tinman]

Brad:

I am sorry but I am going to be nasty here because you deserve it:

<<< I dont know what is going on with you MH,but you need to make up your mind here.
Can a voltage exist across an ideal inductor that has a DC current flowing through it or not?--it's a very simple question,and you can have two answers as you have above. >>>

Just because the current is flowing in one direction you are calling that "DC current?"  This ridiculous nonsense takes its root from my answering the more difficult question and you haven't mastered the concept of what "DC" means relative to talking about coils?

That is not DC current you loonie that is current that is changing in time.

All of this stupid nonsensical idiocy because poor Brad can't make a distinction between constant DC current that does not change with respect to time and current that is flowing in the same direction that does change with respect to time?

Inductors are all about current changing with respect to time and you pull off this silly stunt because you don't know?

You are in the corner with a dunce cap on right now.  People reading are aghast.

MileHigh

That is not DC current you loonie that is current that is changing in time.

In this lesson MH,you will learn what a DC current is.

Once again,i will provide  links that explain this to you.

1-https://en.wikipedia.org/wiki/Direct_current
Direct current (DC) is the unidirectional flow of electric charge. Direct current is produced by sources such as batteries, power supplies, thermocouples, solar cells, or dynamos. Direct current may flow in a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams. The electric current flows in a constant direction, distinguishing it from alternating current (AC). A term formerly used for this type of current was galvanic current.[1]

That is not DC current you loonie that is current that is changing in time.

2-https://learn.sparkfun.com/tutorials/alternating-current-ac-vs-direct-current-dc
DC is defined as the "unidirectional" flow of current; current only flows in one direction. Voltage and current can vary over time so long as the direction of flow does not change.

Please pay careful attention to the highlighted above,where you will note that a DC current can vary in time,as long as the current flow direction remains in one direction.

3-http://whatis.techtarget.com/definition/DC-direct-current
DC (direct current) is the unidirectional flow or movement of electric charge carriers (which are usually electrons). The intensity of the current can vary with time, but the general direction of movement stays the same at all times. As an adjective, the term DC is used in reference to voltage whose polarity never reverses.

4- Here is one you may understand MH-->http://www.physics4kids.com/files/elec_dc.html
The current in DC circuits is moving in a constant direction. The amount of current can change, but it will always flow from one point to another.

Now you should be full bottles on what DC is


Brad

[tinman]

That posting is just sad Brad.  It shows how you are so limited in your understanding and how your powers of conceptualization are so weak that you would think that your response to my posting is legitimate.  Instead of trying to solve the easier question as is and being puzzled and intrigued by the answer to the more difficult question and how I arrived at it it, you are the "problem student" that can't understand the question and objects to the wording in the question.  It's just sad.

The wording in your question is very clear MH. An ideal voltage source is supplying 4 volts across an ideal inductor for a period of 3 seconds.

You wrote it your self.

Brad

[MileHigh]

In this lesson MH,you will learn what a DC current is.

Once again,i will provide  links that explain this to you.

1-https://en.wikipedia.org/wiki/Direct_current
Direct current (DC) is the unidirectional flow of electric charge. Direct current is produced by sources such as batteries, power supplies, thermocouples, solar cells, or dynamos. Direct current may flow in a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams. The electric current flows in a constant direction, distinguishing it from alternating current (AC). A term formerly used for this type of current was galvanic current.[1]

2-https://learn.sparkfun.com/tutorials/alternating-current-ac-vs-direct-current-dc
DC is defined as the "unidirectional" flow of current; current only flows in one direction. Voltage and current can vary over time so long as the direction of flow does not change.

Please pay careful attention to the highlighted above,where you will note that a DC current can vary in time,as long as the current flow direction remains in one direction.

3-http://whatis.techtarget.com/definition/DC-direct-current
DC (direct current) is the unidirectional flow or movement of electric charge carriers (which are usually electrons). The intensity of the current can vary with time, but the general direction of movement stays the same at all times. As an adjective, the term DC is used in reference to voltage whose polarity never reverses.

4- Here is one you may understand MH-->http://www.physics4kids.com/files/elec_dc.html
The current in DC circuits is moving in a constant direction. The amount of current can change, but it will always flow from one point to another.

Now you should be full bottles on what DC is

Brad

This is the takeaway from this discussion:  All of this stupid nonsensical idiocy because poor Brad can't make a distinction between constant DC current that does not change with respect to time and current that is flowing in the same direction that does change with respect to time?

Again, it's sad that your understanding is so weak and your ability to conceptualize is so limited.

You were "going after me" because you said that I supposedly said "DC current through an inductor results in no voltage across the inductor and DC current through an inductor also results in voltage across an inductor" as if that is a contradiction.

Your own cited definition of "DC current" includes a variable current so that means that in fact there is no contradiction.  So you are bonkers again.

But all that is beside the point, you are simply failing to draw a distinction between unchanging current and changing current in the context of discussing coils.  It's just sad and it's a total fiasco.

[tinman]

tbh this is what I find ironically interesting. I believe the way your question was asked, in the context that it was asked, and during the heated moment of debate it was asked, included
well, not quite a deceptive, but an 'unorthodox' aspect. I know to you it seems common practice but there was a certain degree of "hmmm could this be a trick?".. When I first looked at the varying
voltages I was thinking hmm how does that work.. It never occurred to me the voltage from the
source could vary but then that was sort of the point of you bringing it up, that it's a variable we
are supposed to pick up on and account for given the test parameters. I believe this actually
caused some people to look at it in a much deeper way than they may have prior. It personally
threw me into some deep thought. In the end your question, though not answered satisfactorily
in your opinion, may have taught more than you think. You may have helped to strengthen
a belief some of us would have not held in the first place prior to really analyzing this scenario.
Had you asked a question more like idk let's say solve for current in the inductor at t=0 through t=9 given x voltage at t=0 with an R then Brad would have probably just solved it, and if he didn't know, would have probably brushed up online before solving it. But then, there's the possibility
he may have never thought about this entire 0 resistance superconductive inductor scenario. maybe he has idk..

Magneticitist
The voltage across the ideal inductor dose not vary with time,as it is from an ideal source,and the value is set at 4 volts,for a time period of 3 seconds.

MH will not attempt to calculate what happens,as he dose not know--he cannot understand the difference between ideal and real. The real coil could have .000000000000000001 ohms of resistance,but it is still an infinite amount away from being ideal--no resistance. He seems to think that 100,000000000 miles is close enough to an infinite mileage--but it is not even a grain of sand on all the beaches of the world.


Brad