Pages created and updated by Terry Sturtevant Date Posted: November 9, 2017


Electronic systems consist of different blocks which are interconnected. A block diagram indicates which blocks interact with each other. However, in addition to simple indicating which blocks interact, it is possible for a block diagram to indicate the type of signal(s) which connect the blocks.
One way this kind of diagram can be particularly useful is that if each block identifies the type of signals that it requires for inputs and outputs, then it can only directly connect to other blocks providing or requiring those specific signals. In this way, any device added to a diagram implicitly indicates what other devices will also be needed to connect it with some other component.

Block Diagram elements

Signals for block diagrams library for Dia
To make block diagrams more informative, I've created some of my own symbols for signal types like in both horizontal and vertical versions, and in versions for both single and multiple signals. There are also symbols for common interfaces, such as These make it easy for a block diagram to show not only what items are connected, but the types of connections between them as well.

Signal types (single)

Signal types (multiple)

Interface types


Motors and actuators




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