Lewin's NCF Experiment and Lecture

[poynt99]

Yes,the sum equals 0,but what has that to do with what Lewin claims?.

It has everything to do wtih Lewin's claim that Kirchhoff does not hold in this case. In his lecture he is clearly not only comparing apples and oranges, but he is muddling the whole affair entirely.

We can sum up voltages around any circuit to equal 0 if we measure from certain points using certain polarities.

In other words, if you always ensure your measurement apparatus is decoupled from the DUT, you will not only measure the correct voltages across each component, but you will prove that Kirchhoff holds each and every time. Lewin claims that it does not, and you just proved that it indeed does hold every time.

It would seem to me that Lewins claim is correct,when measuring across the two resistors,as the sum is not 0,it is the induced 1volt EMF in this case,being the total across each resistor.
If we have a current flow,then we are not measuring just the E filed,but the EM field.
If it were just the E field,then Kirchhoff law may hold,in that the measuring was carried out incorrectly. But as we also have current flow,and a magnetic field,then it would seem to me that Kirchhoff's law dose not hold in this situation.

I can't make much sense out of this last bit. Each statement on its own is either wrong or nonsensical and seems to indicate that you don't understand what you should have just learned.

[tinman]

It has everything to do wtih Lewin's claim that Kirchhoff does not hold in this case. In his lecture he is clearly not only comparing apples and oranges, but he is muddling the whole affair entirely.
In other words, if you always ensure your measurement apparatus is decoupled from the DUT, you will not only measure the correct voltages across each component, but you will prove that Kirchhoff holds each and every time. Lewin claims that it does not, and you just proved that it indeed does hold every time.
I can't make much sense out of this last bit. Each statement on its own is either wrong or nonsensical and seems to indicate that you don't understand what you should have just learned.

Perhaps a review of my posted result's?,as you seemed to have missed something.

Diagram 1 and associated scope shot has to be inverted in order for us to do our loop measurement points in order.So invert the scope probe position,and invert the scope shot,so as to gain the correct value,which will be negative 400mV.

Diagram 2(which is the correct polarity) and associated scope shot,shows us the potential across the 1k resistor. We can safely say that it is close to 800mV.

Diagram 3(which is the correct polarity) and associated scope shot,again shows us a value that is close to negative 400mV.

800mV-400mV-400mV gives us a value of 0 volt's.
But we still have the 100 ohm resistor to measure,and so our total value is not 0 volts.

Kirchhoff's voltage law is based on the assumption that there is no fluctuating/changing magnetic field linking the closed loop. In our DUT,there is clearly a changing/fluctuating magnetic field linking the loop,and this can be seen in all my scope shot's by the reversing current flow across each measuring point during the decoupled tests-and all the other tests carried out in this thread that i have done.

Quote-KVL is based on the assumption that there is no fluctuating magnetic field linking the closed loop.  In the presence of a changing magnetic field the electric field is not a conservative vector field. Therefore the electric field cannot be the gradient of any potential. That is to say, the line integral of the electric field around the loop is not zero, directly contradicting KVL.

The results of my test,the results of Lewins test,and the definition of KVL indicating that a changing magnetic field linking the closed loop make KVL invalid in this case,seems to all fit together,and Lewins statement is correct.

What have i missed here Poynt?.


Brad

[minnie]

  I live on the side of a hill. I set out to shepherd my sheep, go down to the river,
  up to the windmill and then go home. When I get home I'm at the same elevation
  as when I started.
      I can't walk anymore and the kids got me this-

[tinman]

  I live on the side of a hill. I set out to shepherd my sheep, go down to the river,
  up to the windmill and then go home. When I get home I'm at the same elevation
  as when I started.
      I can't walk anymore and the kids got me this-

It's a good thing that there was not a land slide under your house while you were away from home,as then you would have gained more energy going down hill to the river than it took you to get back home

The energy form point A to point B and back to point A can change if there is another force acting upon one of those points,or the area between the points.

I drove my boat from my house jetty, down river to my favorite fishing spot,and used 2 liters of fuel.
I drove my boat back to my house jetty from my favorite fishing spot,following the same path,but used 3 liters of fuel on the return trip.

Brad

[minnie]

  I'm a bit baffled today, I came across the term "convection current". Then I
  encountered "self capacitance".
    I was just wondering why after seven decades I've all of a sudden taken an
  interest in these things, and I've worked that one out, it's Google!
             John.