Analysis of a circuit often starts with producing a visual representation of a circuit’s important properties. Rather than using an artistic representation of a real circuit, schematic diagrams are typically used instead. An example of a circuit schematic is given in Figure 1.2.1.
Physically connected to Earth. Acts as charge source/sink.
Common
Circuit reference. Assume V=0 at common.
So, lines represent wires connecting terminals of circuit elements. If a dot is present where two lines intersect, then it means that those two wires are connected. We have also labeled all of our components and provided labels and directions for currents.