A block diagram is a type of a system in which the main components or works are represented by cubes joined by lines that reveal the relationships of the cubes.
In electrical engineering, a design may often start as a very higher level block diagram, getting more and more detailed block diagrams as the design develops, eventually ending in block diagrams comprehensive enough that each individual block can be easily executed (at which point the block diagram will be also a schematic diagram). This is referred to as top down layout.  Geometric shapes are frequently used at the diagram to aid interpretation and clarify meaning of the procedure or model. Each engineering field has their own significance for each shape. Block diagrams are used in each discipline of engineering. They're also a valuable source of concept building and educationally beneficial in non-engineering areas.
Block diagrams are usually used for higher degree, less comprehensive descriptions which are meant to clarify overall concepts without difficulty for the specifics of implementation. Contrast this with the schematic diagrams and layout diagrams used in electric engineering, which show the implementation details of electric parts and physical structure.
As an example, a block diagram of a radio is not expected to demonstrate each and every connection and dial and switch, however, the schematic diagram is. The design of a wireless doesn't show the diameter of each connection from the printed circuit board, but the layout diagram does.
In process management, block diagrams are a visual language for describing actions within a intricate system where blocks are black boxes which represent logical or mathematical operations which exist in order from left to right and top to base, but not the physical entities, like processors or radiators, that execute these operations. It's possible to create such cube diagrams and execute their functionality with specialized programmable logic controller (PLC) programming languages. )
Block diagrams rely on the principle of this black box in which the contents are hidden from view to avoid being distracted by the facts or because the details aren't known. We all know what happens, we all know what happens, but we can not see the way the box does its own work.
To create an analogy to the map making planet, a block diagram is very similar to a highway map of an entire nation. The major towns (serves ) are listed but the small county roads and city streets aren't. When troubleshooting, this large degree map is helpful in narrowing down and isolating in which a problem or error is.
In biology there's a growing use of engineering fundamentals, techniques of evaluation and ways of diagramming. There's a similarity between the block structure and what's named Systems Biology Graphical Notation. As it is there is use created in systems economics of the block diagram technique exploited by controller technology where the latter itself is a program of control theory.
An illustration of this is the function block structure, one of five programming languages found in part 3 of this IEC 61131 (view IEC 61131-3) standard that's highly formalized (see formal system), with strict rules to the diagrams must be built. Directed lines have been utilised to link input variables to block input signal, and block outputs to output factors and inputs from different cubes.