Basic DC Theory
DC CIRCUIT TERMINOLOGY
Figure 9 Schematic Diagram
One-Line Diagram
The one-line, or single-line, diagram shows the components of a circuit by means of single lines
and the appropriate graphic symbols. One-line diagrams show two or more conductors that are
connected between components in the actual circuit. The one-line diagram shows all pertinent
information about the sequence of the circuit, but does not give as much detail as a schematic
diagram. Normally, the one-line diagram is used to show highly complex systems without
showing the actual physical connections between components and individual conductors.
As an example, Figure 10 shows a typical one-line diagram of an electrical substation.
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