DC Circuits: Current Origin and Conductors

This lecture covers the origin of current in a conductor when a voltage is applied, leading to the creation of an electric field inside the conductor. The movement of charges generates a current, following Kirchhoff's rules. It explains the concept of current as the quantity of charges passing through a conductor per unit time, with historical conventions regarding the direction of current flow. The lecture also discusses the density of electronic charges in a material and the behavior of mobile charges in a conductor. Examples illustrate current flow in conductors of different sections and the application of Kirchhoff's rules in circuit analysis.