# Schematic

A diagram that interconnects icons to describe an electronic circuit. This was reasonable when circuits were assembled from discrete components.

The icons indicate the function of a gate, but don't provide information as to its size or location. The icons are not placed where the gates will be. Nor is the length of interconnect indicated, or even known.

Although annotations can be made to the schematic to provide this information (when it is known) this is rarely done. Instead the schematic is converted to a list of nets and transistors, with annotations. This list is used to place and route the actual gates.

A carefully drawn schematic is thus a temporary representation. Work done arranging gates to clarify function is wasted. The list becomes the reference document after "schematic capture". Further engineering work is done with a text editor.

The art of placing gates and routing interconnect is badly done by a computer. The "common sense" of computer and human are vastly different. The result is usually a spagetti circuit, impossible to understand or modify.