tech99's latest activity
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tech99 replied to the thread I Gauss' law seems to imply instantaneous electric field.So far as I can see, and I may be incorrect here, when the switch is closed there is oscillation, which is gradually damped out by... -
tech99 replied to the thread Electromagnet magnetic field issue.I assume the wire is the same gauge, copper, enamelled? If so I strongly suspect the material of the core as the problem.
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Symmetry is not a likely reason for magnetic differences. Open gaps in the magnetic path, are a more likely cause. What material is...
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tech99 replied to the thread Electromagnet magnetic field issue.It is easy to try quenching the core if making an electromagnet. I have found it works on nails used by pupils as cores for making...
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tech99 replied to the thread Electromagnet magnetic field issue.I have often turned nails into "soft iron", by heating and quenching them, for pupils making magnets. This makes the core lose its...
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tech99 replied to the thread Electromagnet magnetic field issue.Thank you. I think the annealing process makes the steel magnetically "soft", so it does not retain magnetism.
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tech99 replied to the thread Electromagnet magnetic field issue.I remember turning mild steel into soft iron by heating it to cherry red than quenching in water.
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tech99 replied to the thread A Advice for 100 MHz resonator.If you use a parallel plate transmission line and tune to its resonant frequency, the electric field max position will correspond to a...
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tech99 replied to the thread I Off resonance driving of a MW/RF cavity.A waveguide does not follow the shape of the ordinary resonant curve, because it has sharp cut-off on the low frequency side. The PCB...
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tech99 replied to the thread I Off resonance driving of a MW/RF cavity.The Lorenzian shape arises because you have placed matter within the cavity. It appears that the material has losses at 100 MHz, which...
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tech99 replied to the thread I Effective absorption coefficient of gold nanoparticles.The particles are only 1/100 wavelength in size and the 100nm layer is only 20 particles thick, so scattering might be rather small.
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tech99 replied to the thread Weird near-field phenomenon I get in my EM simulation.In the Hertz experiment, he did not rely on the waves impinging on the wire. He arranged for an antenna to sample both the wave on the...
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tech99 replied to the thread Weird near-field phenomenon I get in my EM simulation.Hertz carried out what was, in effect, a race between a wave on a wire and a wave in free space *. If I am reading his paper correctly...
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tech99 replied to the thread When 50,000 volts go through a wire at 5,000,000 FPS - The Slow Mo Guy.The propagation along a wire will depend on the shape into which it is bent and the proximity to other parts of the wire and other...
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tech99 replied to the thread When 50,000 volts go through a wire at 5,000,000 FPS - The Slow Mo Guy.2. I do not agree with this statement . The wave follows the wire, as a waveguide, so that if the wire is in a tortuous path, say a...
