To make an analogy to the map making planet, a block diagram is comparable to a highway map of an entire nation. The significant cities (serves ) are listed but the small county roads and city streets aren't. When troubleshooting, this large degree map is useful in narrowing down and isolating where a issue or error is.
For example, a block diagram of a wireless isn't expected to demonstrate each and every link and dial up and switch, but the schematic diagram is. The schematic diagram of a radio does not demonstrate the diameter of every link in the printed circuit board, but the layout diagram does.
A block diagram is a diagram of a method where the principal components or functions are represented by blocks connected by lines which reveal the connections of the cubes.
Block diagrams are usually used for higher degree, less detailed descriptions which are intended to clarify overall concepts without difficulty for the specifics of implementation. Contrast this with the design diagrams and design diagrams used in electrical technology, which show the implementation information of electric elements and physical construction.
In electrical engineering, a style may often start as a quite significant level block diagram, getting more and more detailed block diagrams as the design progresses, eventually ending in block diagrams comprehensive enough that each individual block can be readily implemented (at which stage the block structure is also a schematic diagram). This is referred to as top down style.  Geometric shapes are frequently used at the diagram to aid interpretation and clarify meaning of the procedure or version. Each engineering field has their own significance for every form. Block diagrams are used in every discipline of engineering. They're also a valuable source of theory building and educationally beneficial in non-engineering disciplines.
Block diagrams rely upon the principle of this black box where the contents are hidden from view either to avoid being distracted by the details or because the details are not known. We know what goes in, we know what happens, but we can't see how the box does its own work.
An illustration of that is the function block structure, one of five programming languages described in section 3 of the IEC 61131 (see IEC 61131-3) benchmark that is very formalized (see formal method ), with stringent rules for how diagrams should be assembled. Directed lines have been utilised to connect input factors to block input signal, and prevent outputs to output variables and inputs from other cubes.
In process control, block diagrams are a visual language for describing actions in a complex system in which blocks are black boxes which represent mathematical or logical operations that take place in sequence from left to right and top to bottom, but not the physical entities, such as chips or relays, that execute these operations. It is likely to create such block diagrams and implement their performance with specialized programmable logic control (PLC) programming languages. )
In biology there's a growing use of technology fundamentals, techniques of evaluation and methods of diagramming. There's a similarity between the block diagram and what's named Systems Biology Graphical Notation. As it is there's use made in systems biology of the cube structure technique harnessed by control engineering where the latter itself is a program of control theory.