A design diagram refers to a specific kind of circuit diagram that uses standard electrical/electronic symbols instead of images to demonstrate how a circuit (or part of it) functions. Below is a normal 3-wire motor controller circuit utilizing a typical short stop stop - start pushbutton channel working with a schematic diagram. (Momentary here means that the button/switch you activate will go back to its default place once you let go of it, usually by a spring that compels the button/switch to do this.)
Here is another schematic diagram showing precisely the identical circuit, connections and components and it looks different but they both fall into precisely the same category.
Think of it this way; a circuit structure is any type of diagram that demonstrates how a circuit functions where the major objective is the proper wiring of elements and their connection to each other rather than physical place relative to each other or planning prototypes. Nonetheless, in some uses classifying diagrams can be difficult so choose this as general information. I've found this is especially true when working with much more complicated circuits and electronics. I'm likely to work with a simpler but average industrial circuit since these circuit set ups are exactly the same, but yet where you can observe how each kind of diagram shows the operation of the circuit in their own manners.
Following is a specialized variant of a diagram. The major goal of this diagram is to show the logic (referring to electric control) of a circuit. This diagram is the one I mainly come across in my line of work, and it's extremely effective for troubleshooting issues or learning how a circuit functions. Some frequencies are so enormous that most types of schematic diagrams need to be read in increments from novel form (typically with coded numbers so info can be easier found). Again, here is the exact specific circuit because the first 2, however considering it in ladder shape.
Pictorial schematic diagrams, or pictorial circuit diagrams are essentially the same thing with exactly the same purpose, however they use images of components inside the circuit instead of symbols. Again, here's the exact specific circuit (almost except a controller was included and they're utilizing conductors L1 and L3 instead of L1 and L2.
Right, less mess? I have enough information in all of these diagrams to know just what this circuit will do and also where to look for problems. Hope that this helps. ( Note: don't confuse circuit or schematic diagrams together with wiring diagrams; wiring diagrams will often show images of elements such as the pictorial, and how the whole or portion of a circuit is wired. The difference is that wiring diagrams typically put an emphasis on real physical place of necessary elements relative to each other that basically tell a layman Just What to do concerning the wiring. )