Recent content by HydroGuy

I'm having some trouble getting a good understanding of how the EM fields are working in a circuit. Essentially, Maxwell's equations and boundary conditions at a perfect conductor are confusing me. If, in a perfect conductor, the E and B fields are zero, then how does a voltage appear in a...

So... the key to low power is to have a very high load impedance? I don't think I'm comprehending this correctly.

In University we almost always deal with voltage sources that can supply whatever current needed. What determines the amount of power "drawn", is it purely the resistance? How do we design for low-power?

OK, thanks but that isn't really answering my question. Why does increasing the voltage decrease the power loss in the line?

I've long understood that voltage is stepped-up in power t-lines to decrease losses, however, I've never really understood the math reasoning behind it. Isn't P = V^2/R the same as P = I^2*R? If so, it seems that either increasing V or increasing I would invoke the same losses... Could...

Ginlong provides power and voltage curves for the model, but I'm looking to test/confirm it and do some additional testing in the future. http://www.ginlong.com/images/200906/1000-PMG-Power-Curve-1.jpg http://www.ginlong.com/images/200906/1000-Open-Circuit-Voltage-1.jpg Couldn't I...

Hmm, I don't think it's a dynamo... it outputs three phase power. Here is the website: www.Ginlong.com I know that I need a voltmeter, but we would need some type of load to deliver the power to, right? I could find open circuit voltage just by spinning it, but I want to see the power...

I need to test a variable-speed generator attached to a small wind turbine (lets say). I want to see how much power its producing, as well as the current. It outputs in three-phase Y configuration at frequencies varying from 3 to 9 Hz. The generator is rated at 1.2 kW at 550RPM, with an open...

Let's say we have a dipole antenna that we are using to radiate a signal. The dipole antenna (think rabbit ears) has two ends that appear to me to be open circuits. Maybe my problem is that I have too much circuit background and not enough EM, but how does current flow through these rabbit...

Yes I understand that, but since I'm taking the partial with respect to z, the answer would be... -B*sin(w0*t - Bz) I didn't explain myself clearly, that's why your confused. I think that we agree however.

Er... nevermind. I think you just neglect the first part since we're only concerned with the z variable, and treat it as a sin(-B*z), right?

Homework Statement For example: the function is A0sin(w0*t - B*z) If I take the partial derivative with respect to z, how do you go about this? In my years at uni, I don't know if this has ever come up. Homework Equations The Attempt at a Solution My initial thoughts are...

Yes, but you don't seem to understand the question. I realize all of what you said, my question is WHY. Why does an inductor - a coil of wire - oppose the flow of electrons through it? I understand that an inductor is the shape of a coil to amplify the magnetic field, and that it is this...

Thanks Bob S - good stuff. Lets say we had a superconducting wire with R=0 hooked up to an ideal voltage source at 60 Hz. If we twisted the superconducting wire into a loop, would it create an inductor? Would the current then lag the voltage by 90 degrees? It would it depend on the load...

Thanks. Where does the shunt capacitance of a current-carrying wire come from? How does it exactly cancel out the inductance? Can anyone address my questions regarding inductors and coils, and why a loop causes an exact 90 degree phase lag in current (discarding resistance)? It just seems...