Think of it in this way; a circuit structure is any sort of diagram that illustrates how a circuit functions where the principal objective is that the appropriate wiring of elements and their connection to each other rather than physical location relative to each other or planning prototypes. However, in some applications classifying diagrams can be challenging so take this as general advice. I have discovered this is especially true when dealing with much more complex circuits and electronic equipment. I'm going to use a simpler but average industrial circuit because these circuit set ups are exactly the same, but where it is possible to see how each kind of diagram indicates the function of the circuit in their own ways.
A schematic diagram refers to a specific kind of circuit diagram that utilizes standard electrical/electronic symbols instead of pictures to show the way the circuit (or part of it) works. Below is a standard 3-wire motor controller circuit using a standard short stop stop - start pushbutton station utilizing a schematic diagram. (Momentary here means that the button/switch you activate will go back to its default place once you physically let go of this, typically by a spring which forces the button/switch to get this done.)
Much less clutter, right? I've got enough info in each one these diagrams to know precisely what this circuit will do and where to start looking for issues. Hope this helps. ( Note: do not confuse lecture or circuit diagrams with wiring diagrams; wiring diagrams will usually show pictures of elements like the pictorial, and how the whole or part of a circuit has been wired. The distinction is that wiring diagrams typically place an emphasis on real physical place of necessary elements relative to each individual that basically tell a layman Just What to do concerning the wiring)
Here's a version of a diagram. The major intent of this diagram is to demonstrate the logic (referring to electrical management ) of a circuit board. This diagram is the one I mostly encounter in my own line of work, and it is very successful for troubleshooting problems or learning how a circuit works. Some circuits are so huge that most types of schematic diagrams have to be read in increments in novel form (normally with coded numbers so that info can be simpler found). Again, here is the identical specific circuit because the first two weeks, but looking at it in ladder shape.
Here is another schematic diagram showing precisely the same circuit, connections and components and it appears different but they fall into precisely the identical category.
Pictorial design diagrams, or graphic circuit diagrams are essentially the same thing with exactly the exact same purpose, but they use images of components within the circuit rather than symbols. Again, here is the exact same exact circuit (almost except a control transformer was added and they're utilizing conductors L1 and L3 rather than L1 and L2.