In my idea the tension change after connecting the circuit to a battery is immediate, while the current takes some time before moving. That should be sufficient to prove my question but, so why in a RC circuit the opposite happens?
At this point i understand the phase practically speaking, for example when some AC motor is not well connected, it will turn in the wrong direction. But in a circuit what does it mean?In AC circuits, a C gives a 90 degree phase shift, and L gives a 90 degree phase shift in the opposite direction.
Careful how you word that, it sounds like it would result in infinite current. The dV/dt term opposes current instantaneously.If there is no charge in a capacitor and a battery is connected across it, there is initially no opposition to the current flowing in to charge the plates. I
V or I, not V and I. It means we get imaginary power. We call that VAR for volt-amp-reactive.But in a circuit what does it mean? V and I shifted by 90deg, what does it mean？
Good point. It is only good for an intuitive feel for how the current could start high and the voltage low.Careful how you word that, it sounds like it would result in infinite current. The dV/dt term opposes current instantaneously.
The impulse is composed of all frequencies, with very high frequencies dominating the initial time t=0. At that time, the capacitor acts approximately like a simple wire for those very high frequencies. That should give some intuitive feel for the initial transient response.At switch-on, we have to calculate the impulse response of the circuit.
Not only one? for example the 50Hz at homeThe impulse is composed of all frequencies.
If you short-circuit a battery, there is a very small resistance in the shorting wire and the voltage drop across the shorting wire is small. (There is still an internal resistance in the battery, but we can ignore that for now.) The current is very high.In my opinion the problem is similar for both circuits. When i switch on I and V should have the same phase. And then, after some time, they would be dephase by inductor or condensator
No. An impulse or a step input both have components of frequencies from low to very high. It take very high frequencies to give the sharp increase. Here is the unit step function in the time domain and its associated frequency spectrum:Not only one? for example the 50Hz at home