Think of it in this way; a circuit structure is any type of diagram which demonstrates how a circuit operates where the primary goal is the proper wiring of components and their connection to each other rather than physical place relative to each other or intending prototypes. Nevertheless, in some uses classifying diagrams can be difficult so accept this as general information. I've discovered this is especially true when dealing with more complicated circuits and electronic equipment. I'm going to use a more straightforward but average industrial circuit because these circuit set ups are the exact same, but where you can see how each kind of diagram shows the purpose of the circuit in their own manners.
Pictorial schematic diagrams, or graphic circuit diagrams are basically the exact same thing with exactly the identical function, however they use pictures of components within the circuit rather than symbols. Again, here is the exact precise circuit (almost except a controller was inserted and they're using conductors L1 and L3 rather than L1 and L2.
A design diagram refers to a specific sort of circuit structure which utilizes standard electrical/electronic symbols rather than pictures to show the way the circuit (or a part of it) functions. Below is a typical 3-wire motor controller circuit employing a typical short stop halt - start pushbutton channel utilizing a schematic diagram. (Momentary here means the button/switch you trigger will go back to its default position once you physically let go of it, typically by a spring which forces the button/switch to do this.)
Less mess, right? I have enough information in all these diagrams to know precisely what this circuit will do and also where to start looking for problems. Hope that this helps. ( Note: don't confuse lecture or circuit diagrams with wiring diagrams; wiring diagrams will typically demonstrate images of elements like the pictorial, and the way the whole or portion of a circuit has been wired. The distinction is that wiring diagrams typically put an emphasis on actual physical location of necessary components relative to each individual that essentially tell a layman exactly what to do concerning the wiring)
Here is another schematic diagram demonstrating the same circuit, components and connections and it appears different but they both fall into exactly the exact identical category.
Here's a version of a diagram. The main intention of this diagram is to demonstrate the logic (referring to electrical control) of a circuit board. This diagram is the one that I mainly come across in my own line of work, and it is extremely successful for troubleshooting problems or learning the way the circuit works. Some frequencies are so enormous that most kinds of schematic diagrams need to be read in increments in novel form (typically with coded numbers so info can be simpler found). Again, here's the same precise circuit as the first 2, but looking at it in ladder type.