Current#
Definition: Current
Current is any statistical tendency of electric charges to drift along a specific path.
This movement, despite being along one specific path, is different for different electric charges. Since movement of electric charges is always caused by electromagnetism, positive charges and negative charges will be moving in opposite directions along this path. However, we want to assign a direction
Definition
We quantify the amount of current flowing through a conductor by looking at a cross-section of it and examining the amount of electric charge which passes through this cross-section per unit of time. Naturally, conductors do not have a perfect structure and so this flow might be different for different points of the conductors. These variations, however, are practically unnoticeable and so we often assume that the flow is the same throughout the conductor.
Definition: Average Amount of Current
The average amount of current passing through a given cross-section of a conductor during a time interval \(\Delta T\) is defined as the ratio of the total amount of electric charge \(q\) passing through this cross-section to the duration \(\Delta T\).
Notation
This is usually denoted by \(I_{\text{avg}}\) or \(i_{\text{avg}}\).