Hi guys,
Am a beginner..Finding it difficult to visualize things..Ma Question s..In capacitor,the current leads voltage by 90 deg..Right??So what does it mean??Like before the instant u apply a voltage u get a current??
Right. So there is a current, which appears to be flowing through the capacitor, at the instant power is applied, but there is no voltage across the capacitor until it charges. (one plate with a large number of electrons, the other with a large absence of electrons.) In other words, it acts as a direct short at power up. Once the plates are charged, the apparent current stops flowing, and the voltage appears across its terminals, and it act like an open.
It will probably help to think of Voltage as Potential, and Current, as flow. If you think of potential energy (voltage,) verses kinetic energy (current,) then you should get some clarity.
There is a brick on the roof. It is not moving. It has a potential to do work. That potential is the distance above ground where the brick is sitting. Since the brick is not moving, it has no Kinetic energy. Similar to the potential difference which exists across the two wires in an outlet in your home. To continue, if nothing is plugged into the outlet, no current is flowing.
If the brick is falling the potential is being turned into kinetic energy.
Current appears to be flowing through the cap, until the plates are charged, at which point a potential difference appears across its terminals.
I hope that helps to clear it up.
Shoot, I'm slow. Eric appears to have posted while I was generating this silly opus.