Joule Thief 101

[poynt99]

Damn! Sorry to see him gone.

Who caught his guitar? 

[shylo]

So i take it that you know what is happening in that experiment?.

Well i do not,but i would like to know,and i would like to nut it out for myself

Looking at the circuit below--is this correct to that used in the video?.
If so,i do not see how when a voltage potential of 1 volt is placed across the inductor,that the instantaneous voltage across both resistors is also not 1 volt. In fact,if there is enough supply current to maintain that 1 volt across the inductor,then the two resistors (100 & 900 ohm) should always have 1 volt across them. How he managed to get a negative value across the 100 ohm resister has me a little lost ATM . Even his frozen scope shot show's that he dose indeed have a negative value at the 100 ohm resistor ,and a positive value across the 900 ohm resistor.

UMmm

Brad

Hi Tinman, replace the resistors with diodes, add caps to the diodes , room for 4, the coil will never know it is being tapped.
artv

[Pirate88179]

@ Bill

I believe this may be the one you are referring to?
From 17:00

https://www.youtube.com/watch?v=imlqEKrfS-k

If so,then yes. Ohms law still hold,as the resistance of the light bulb can be calculated as the heat in the bulb increases.
Not sure why he says that ohm's law dose not hold?.


Brad

Yes!!  Exactly.  At 24 minutes in he shows the break down of Ohm's law and why it does not hold.

Thank you for finding this, it would have taken me a long time to do so.  I watched this about 6 years ago or so and MIT has taken the vids down...some of my saved links are to youtube but most were to MIT.  Here he shows the current going up on a curve relative to the voltage and then tapering off and never reaching the level Ohm's law says it should be.

Like I said, I would have thought this was Nobel Prize stuff and would have made many headlines.  This man obviously knows much more about this than I ever will so I will not argue if he is right or not.

Thanks again for digging this one up Brad.  I would be very interested in what .99, TK or MH has to say about Dr. Lewin's conclusions here.

Bill

[poynt99]

Yes!!  Exactly.  At 24 minutes in he shows the break down of Ohm's law and why it does not hold.

Thank you for finding this, it would have taken me a long time to do so.  I watched this about 6 years ago or so and MIT has taken the vids down...some of my saved links are to youtube but most were to MIT.  Here he shows the current going up on a curve relative to the voltage and then tapering off and never reaching the level Ohm's law says it should be.

Like I said, I would have thought this was Nobel Prize stuff and would have made many headlines.  This man obviously knows much more about this than I ever will so I will not argue if he is right or not.

Thanks again for digging this one up Brad.  I would be very interested in what .99, TK or MH has to say about Dr. Lewin's conclusions here.

Bill

There is nothing Nobel about this stuff Bill. It's just Lewin making trying to make a big deal out of nothing. There is no "breakdown" as he calls it, just basic physics.

[poynt99]

At any chosen moment of time, I still equals V/R, i.e. Ohms's law holds.