I'm pretty sure USB cables can tolerate much higher voltages and current than the nominal 500 mA for USB 2.0 and 900 mA for USB 3.0. To reach the breakdown voltage of the dielectric used in the cable you would probably have to apply more than 200 V...
However the ports are much less...
Wasn't sure about the second equation but yeah this looks correct.
And I can't edit my last post but in "3*400V*130A", instead of 400V I meant "400V/sqrt3" if 400V is indeed the phase to phase voltage as mentionned earlier.
I'm currently doing electrical engeering and yeah Emag was one of the hardest. But strangely, at my university, the linear control class is the most failed. But doing it this semester, I can tell it's just a teacher thing :P.
I believe this is wrong if 400V is your phase to phase voltage.
Power in a three-phase system is 3*phase to neutral voltage*current on one phase. So this would be 3*400V*130A.
The fact that you are dealing with three-phase systems is irrelevant in the discussion here. The principle would be the same if the question was about two monophase systems.
What's important is that the two systems have a common point between them. Just consider two AC sources that have their...
I don't see how this thing could be anything else than a standard inductor (with poor inductance because of the lack of ferrite core) with little parasite capacitance and non-neglectable induced current losses.
As for your last question, I can't say :P.
My english is not 100% perfect. But I meant the circuit to which you hook up your fractal coil :P. I said "global" because one could say there are extra circuits within the fractal coil itself if some wires are connected.
If you have a bunch of wires wrapped around in a funny way but with only one coil hooked up to the circuit, the thing will be a standard inductor. The other wires, depending on their magnetic permeability (probably low if it's copper) will serve as the core of the inductor. If the other wires...
This is a good post and great addition to the discussion^^.
But btw, we all know that current isn't "pushed" :P. But sometimes using familiar expressions help understand the problem :). We also often say that toasters and ovens "pull" a lot of current!
"Power-wise" you get less than Vmax because the voltage oscillates between -Vmax and Vmax!
Now for the 0.707, there is the proof here : http://en.wikipedia.org/wiki/Root_mean_square#Average_electrical_power.
You could have kept the max voltage throughout. It's just that they convert it to rms value from the beginning because that's what is used in real life applications. Keeping the max value (amplitude) instead of rms value would do no harm to the equations. It's just that at the end you'd have...
We usually use rms voltage because this is what's important in power consumptions considerations and such.
For example, we say that the voltage of a common power outlet is 120 V which is its rms value. This allows easy calculations of power consumption because an ac voltage of 120 V rms will...
I don't know what you just did there but if you apply V(t) = A ln(t) to an inductor, the current will be I(t) = 1/L * (t ln(t) - t). Current in an inductor is the integral of voltage.
You mean use some sort of analogy like the one of the spinning wheel for an inductor? I can't find one, but...