The position of the driving source does not matter for the field generated by the wire itself, as long as signal travel times can be neglected, only magnitude and phase of the sum current counts.(...) since each signal is fed in from a different end of the wire pair. Does this in fact have no effect in terms of the emitted fields?
As already mentioned, voltage (generating an E field) and current (H field) can and should be analyzed separately as long as the circuit dimensions are small compared to wavelength. That's surely the case for 100 Hz (λ = 3000 km). But you don't need to refer to voltage when analyzing the magnetic field of a double wire line. In addition to the concentric field of the current sum, there's a dipole field depending on the current difference and wire distance. The dipole field decays fast and is effectively suppressed by twisting the wires. It can be only sensed in the wire's vicinity.While I claim no expertise in this area, it seems to me that the voltage potential between the two wires would produce a 100Hz electrical field aligned with the plane of intersection between them. And, although the currents oppose, they do not sum to zero because there is a 100Hz positive/negative charge symmetry between the two conductors and this would produce a magnetic field at right angle.
As 100Hz is treated the same as DC, visualize a solenoid with an iron rod in the centre and consider the next force at the 1st peak of the sine wave as if it was just DC.At your suggestion I have included a drawing of the three examples of interest. Let's assume a 100Hz 2Vpp signal and all load resistance in the coils.
In the new examples 2 and 3, I have put a DC offset on the signals. In 3, one signal is inverted.
As previously stated, I am trying to understand the differences between magnetic the emitted electric and magnetic fields of each configuration.
Please note that the wires are parallel, in contact with each other and not twisted.
View attachment 122607
Yes, noted. For an analysis of the dipole field involved by the two wires, the exact geometry (wire diameter and separation) must be considered. Because these field components are rather small, I don't see much sense in the analysis for the present problem.Please note that the wires are parallel, in contact with each other and not twisted.
"It is remarkable that Ohm himself,misled by the analogy between electricity and heat,
... entertained an opinion of this kind, and was thus, by means of an erroneous opinion, led to employ the equations of Fourier to express the true laws of conduction of electricity through a long wire, long before the real reason of the propriateness of these equations had been suspected.
Thank you for explaining further. I will consider the question solved and another lesson learned. But what do CM and DM stand for?
And is it possible to have a case where AC adds and DC cancels?
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