The key to reading an electrical drawing or diagram is understanding the meaning behind different symbols. Each symbol corresponds to a different component of the electrical system, such as wires, diodes, resistors and switches. The symbols explain how the components are connected and how power is transferred throughout the system.
Most electrical drawings don't include a reference key, but are based on a standard set of symbols. For example, resistors, which are one of the most common elements of an electrical diagram, are represented by either two straight lines with a series of lines resembling the letter "W" repeated a few times in between or a two straight lines with a clear rectangle in between. The lines represent the wiring and the symbols represent the two most common types of resistors. The ways in which the lines connect these and other symbols conveys information about the overall configuration of the electrical system.
Most diagrams contain several other symbols and lines which represent different items that perform tasks such as supplying a power source, disrupting the power between different diodes or different circuits that perform more specific tasks. By studying a chart of the different symbols, and the purpose of each related component, it is possible to learn how to read any electrical drawing.