Symbols

Description

System boundary: a rectangular box drawn to represent the boundaries of the system under evaluation.

Pathway: flow of energy, material, or information.

Source: outside source of energy of energy delivering forces according to a program controlled from outside.

Box: miscellaneous symbol to use for whatever unit or function is labeled.

Transaction: a unit that indicates a sale of goods or services (solid line) in exchange for payment of money (dashed line).