A block diagram is a diagram of a system in which the principal parts or functions are represented by blocks connected by lines that show the relationships of the blocks. They are heavily used in engineering in hardware design, electronic design, software design, and process flow diagrams.
Block diagrams are typically used for higher level, less detailed descriptions that are intended to clarify overall concepts without concern for the details of implementation. Contrast this with the schematic diagrams and layout diagrams used in electrical engineering, which show the implementation details of electrical components and physical constructio
USAGE- As an example, a block diagram of a radio is not expected to show each and every connection and dial and switch, but the schematic diagram is. The schematic diagram of a radio does not show the width of each connection in the printed circuit board, but the layout diagram does.
To make an analogy to the map making world, a block diagram is similar to a highway map of an entire nation. The major cities (functions) are listed but the minor county roads and city streets are not. When troubleshooting, this high level map is useful in narrowing down and isolating where a problem or fault is.