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What Is a Block Diagram?

Allen Woodruff
Allen Woodruff

A block diagram is a graphical method used to explain the concept of a system without the need to understand the individual components within that system. This type of diagram might be used in a variety of industries to illustrate and educate individuals about how a system operates, either in part or in its entirety. Block diagrams usually will have a logical, methodical flow from beginning to end. Engineers and software programmers are examples of individuals who might be familiar with block diagrams.

Block diagrams essentially are synonymous with flow charts, but a block diagram is generalized in nature. Sometimes block diagrams are used to conceal specific information or processes that might prove to be advantageous or detrimental, whichever the case might be. People who are being presented with a block diagram should be able to develop an understanding of what that block represents. To assist in understanding the block itself, lines should be drawn to the block representing various inputs, outputs or alternative choices.

Scientist with beakers
Scientist with beakers

Depending on the type of process being illustrated, blocks might serve in any capacity that is needed to adequately describe the process or parts of the process. For instance, a manufacturing cell of machine tools might include a drill press, a milling machine and a sanding machine. To illustrate a process within that cell, each machine tool might be represented by its own block. When the manufacturing process is illustrated in its entirety, a single block might be used to represent all of the components within that cell.

A block diagram also can be used to illustrate how a computer program works or how parts of a program work. If, for instance, a program is needed to calculate four different methods of interest rates, a block might represent each of these lines of code for one of these methods. In this way, a supervisor does not need to understand the code itself, as it is written, as long as the purpose of that block is communicated effectively.

Some block diagrams can be used as a way to map out a process as a top-down diagram. For instance, a person who has an inspired project might use a block diagram as a way to convey the idea as a series of individual blocks, each of which helps support the main topic. Later, these individual blocks might then be analyzed and further developed into additional block diagrams as needed. This method can be repeated until the process is mapped out to the satisfaction of all those involved with the project. If compiled and mapped out completely, the block diagram might resemble a pine tree type of structure of the entire project, which is typical for a top-down diagram.

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    • Scientist with beakers
      Scientist with beakers