Joule Thief 101

[tinman]

@ 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

[poynt99]

Part 1

Part 2

Lewin fails to see or explain the experiment for what it is, and wrongly claims that Kirchhoff's law does not hold, when in actual fact it does. He just does not show how. His lecture is very biased towards Faraday and is quite misleading in my opinion.

[tinman]

Part 1

Part 2

Lewin fails to see or explain the experiment for what it is, and wrongly claims that Kirchhoff's law does not hold, when in actual fact it does. He just does not show how. His lecture is very biased towards Faraday and is quite misleading in my opinion.

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

[Johan_1955]

His FACE at the almost end, still playing epiloog, he on his way out?

https://www.youtube.com/watch?v=6SFNW5F8K9Y

[poynt99]

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

I believe I know most of what is going on there, yes.

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?.

Not quite.

First, make it an air-core coil.

Second, the coil is the "primary". The circuit including the two resistors and wire is the "secondary". So there is no electrical connection between the two. Yes, essentially a transformer with a 1-turn secondary.

This is in fact the experiment I encouraged you to perform a number of months ago when we were "discussing" the electric field.