Kapanadze and other FE discussion

[F6FLT]

You don't agree, Brad, but that's the way it is. The induced emf in a circuit crossed by a magnetic flux is obtained either by integrating E along the circuit or by the magnetic flux through its surface, it's a consequence of Stokes' theorem, it's a mathematical identity.
Emf = -dΦ/dt (Faraday's Law) = ∮E.dl  (E electric field = -∂A/∂t, dl a circuit element where current is induced).

If L changes, the circuit of the inductance changes, therefore ∮E.dl changes too, proof that dΦ/dt is also changing.

The formula U=-d(L*I)/dt given by Smudge is correct. See equation 8.69 here

[arhitrade]

Induced voltage is proportional to rate-of-change of flux, and since flux=L*I/N it is proportional to the rate-of-change of the product L*I.  Normally L is a constant so U=-L*dI/dt is correct (the manner in which Gorchelin sums the voltages that negative sign disappears).  But when L is not constant then U=-d(L*I)/dt is the correct version to use.  Gorchelin is in error.  If you believe otherwise please explain why.
Smudge

https://en.wikipedia.org/wiki/RLC_circuit
Pay attention to "Series RLC circuit".
I hope the topic of the error is closed.

[tinman]

You don't agree, Brad, but that's the way it is. The induced emf in a circuit crossed by a magnetic flux is obtained either by integrating E along the circuit or by the magnetic flux through its surface, it's a consequence of Stokes' theorem, it's a mathematical identity.
Emf = -dΦ/dt (Faraday's Law) = ∮E.dl  (E electric field = -∂A/∂t, dl a circuit element where current is induced).

If L changes, the circuit of the inductance changes, therefore ∮E.dl changes too, proof that dΦ/dt is also changing.

The formula U=-d(L*I)/dt given by Smudge is correct. See equation 8.69 here

The part i do not agree with is-Induced voltage is proportional to rate-of-change of flux,

Voltage across a coil is induced by the electric field,there need be no magnetic flux at all if the coil is open. A magnetic field only exist if a current flows through the conductor,but an EFM can exist across a coil without the flow of current,hence-no magnetic field.

So induced voltage is a result of the changing electric field,not the changing magnetic field.


Brad

[F6FLT]

...
Voltage across a coil is induced by the electric field,there need be no magnetic flux at all if the coil is open.

If the coil is open and there is no magnetic flux, there is no induced voltage.
I rephrase:
the induced voltage is the integral of the electric field along the circuit of the inductance and this integral is the corollary of the variation of the magnetic flux through the circuit surface. It is not even a question of physics but of pure math once the magnetic field has been defined as the curl of the vector potential A, and the electric field as E=-∂A/∂t. See the Stockes theorem applied to the magnetic field.
∮A.dl = ∫∫dS.(∇xA) (A, dl, ∇, dS being vectors)

You see the electric field on the left through the vector potential, and the magnetic field on the right in the curl of A. The two equations are strictly equivalent.  [induced electric field along the circuit]  <=> [flux of the magnetic field through the circuit surface]. One can't exist without the other.

[AlienGrey]

bRAD IS DEAD RIGHT!  if I pulse a coil before the magnetic vortex starts explain that, or if I use a caducous wound coil the magnetics is canceled out! or if I block the magnetic field with dielectric charge Leny boys low no longer applies. Your talking conventional theory, that no longer applies here.  Ilke it or not!