Schematics

A schematic, or schematic diagram, is a representation of the elements of a system using abstract, graphic symbols rather than realistic pictures. A schematic usually omits all details that are not relevant to the information the schematic is intended to convey, and may add unrealistic elements that aid comprehension. For example, a subway map intended for passengers may represent a subway station with a dot; the dot doesn't resemble the actual station at all but gives the viewer information without unnecessary visual clutter. A schematic diagram of a chemical process uses symbols to represent the vessels, piping, valves, pumps, and other equipment of the system, emphasizing their interconnection paths and suppressing physical details. In an electronic circuit diagram, the layout of the symbols may not resemble the layout in the circuit. In the schematic diagram, the symbolic elements are arranged to be more easily interpreted by the viewer.

Schematics and other types of diagrams, e.g.,

Transit map, a schematic map (i.e. not drawn to scale, stations are equidistant, lines are drawn at 45 and 90-degree angles)

population density map

Chemical engineering schematic

Electrical circuit diagram for TTL counter, a type of state machine

Schematic of a drive train

exploded view of a 3D-engineering drawing

A semi-schematic diagram combines some of the abstraction of a purely schematic diagram with other elements displayed as realistically as possible, for various reasons. It is a compromise between a purely abstract diagram (e.g. the schematic of the Washington Metro) and an exclusively realistic representation (e.g. the corresponding aerial view of Washington).

In electrical and electronic industry, a schematic diagram is often used to describe the design of equipment. Schematic diagrams are often used for the maintenance and repair of electronic and electromechanical systems. Original schematics were done by hand, using standardized templates or pre-printed adhesive symbols, but today electronic design automation software (EDA or "electrical CAD") is often used.

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