tech99's latest activity
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tech99 replied to the thread Frequency Comb (Photonics, Optics).How would the individual lines in the comb be modulated with different data streams? As you may know, the technique is used for digital... -
tech99 replied to the thread I Does Poisson's equation hold due to vector potential cancellation?.I presume the charges are accelerating and so would seem to radiate in the directions 45 degrees to the axes and zero along the axes.
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tech99 replied to the thread How might electronics be different if AC voltage was 72V at 45 Hz?.Any new invention is going to be really painful to launch, with competing interests trying to strangle the idea at birth. Ridiculous...
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tech99 replied to the thread How might electronics be different if AC voltage was 72V at 45 Hz?.With present day standards, the International Electrotechnical Commission and the UK IET define 50V AC and 120V DC as the upper limit...
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tech99 replied to the thread I Simple thought experiment with Stefan-Boltzmann law: energy.It looks to me that each sphere is radiating into a sky which is slightly obstructed. So the combined radiation measured at a great...
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tech99 replied to the thread In the early days of electricity, they didn't have wall plugs.I also remember and using 2-way adapters for bayonet fittings, so you could have a light bulb and a power take off. No earth pin of course.
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tech99 replied to the thread In the early days of electricity, they didn't have wall plugs.I remember that in the 1940s in the UK, we had power points, but very few. The bayonet light fitting was often used for electric irons...
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tech99 reacted to Baluncore's post in the thread A Reflections at the source point of a transmission line with
Like.
Reflections only occur where there is an impedance mismatch. If the source is matched to the line, then there will be no reflection at... -
tech99 replied to the thread I Do electron density waves accompany EM waves in coaxial cables?.I think so. I believe the wave has the same propagation constants and Zo as the TEM wave, so you don't notice it. It is of small...
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tech99 replied to the thread I Do electron density waves accompany EM waves in coaxial cables?.As far as I can see, I think you do get an electron "wave of compression" travelling along a transmission line in addition to the TEM...
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tech99 replied to the thread Underwater piezoelectric sensor array receive sensitivity.I would endorse the reply #5 from DaveE. Piezo devices have very high resistance but some capacitance. There is no disadvantage in...
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tech99 reacted to DaveE's post in the thread Underwater piezoelectric sensor array receive sensitivity with Like.
It should work if you wire them in series. I wouldn't worry too much about impedance matching since your sound waves will (I think) be...
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tech99 replied to the thread I Gauss' law seems to imply instantaneous electric field propagation.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...
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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...