A schematic diagram refers to a specific type of circuit structure which uses standard electrical/electronic symbols rather than pictures to show the way the circuit (or part of it) functions. Below is a normal 3-wire motor control circuit employing a typical short stop halt - start pushbutton station working with a schematic diagram. (Momentary this means the button/switch you trigger will go back to its default location once you physically let go of it, usually by a spring which compels the button/switch to get this done.)
Pictorial design diagrams, or graphic circuit diagrams are basically the identical thing with exactly the exact identical purpose, but they use pictures of components within the circuit rather than symbols. Again, here is the identical precise circuit (virtually except a control transformer was included and they are utilizing conductors L1 and L3 rather than L1 and L2.
Less mess? I have enough information in all these diagrams to know precisely what this circuit does and also where to start looking for issues. Hope that this helps. ( Note: don't confuse circuit or schematic diagrams with wiring diagrams; wiring diagrams will typically show images of elements such as the pictorial, and also how the entire or portion of a circuit has been wired. The difference is that wiring diagrams typically place an emphasis on actual physical location of necessary elements relative to each other that basically tell a layman Just What to do about the wiring. )
Here is another schematic diagram demonstrating precisely the same circuit, components and connections and it appears different but they fall into the same category.
Think of it in this way; a circuit structure is any kind of diagram that illustrates the way the circuit functions where the primary goal is that the proper wiring of components and their relationship to each other rather than physical place relative to each other or intending prototypes. However, in some uses classifying diagrams can be hard so accept this as overall information. I have found this is especially true when dealing with much more complex circuits and electronics. I'm going to work with a more straightforward but average industrial circuit because these circuit setups are exactly the same, but yet where you can observe how each kind of diagram shows the function of the circuit in their own ways.
Here is a specialized variant of a diagram called a ladder diagram. The major aim of this diagram is to demonstrate the logic (speaking to electric control) of a circuit. This really is the one I mainly encounter in my line of work, and it is very effective for troubleshooting issues or learning the way the circuit functions. Some circuits are so huge that most types of schematic diagrams have to be recorded in increments in book form (typically with coded numbers so info can be simpler found). Again, here's the exact specific circuit since the first 2, however looking at it in ladder form.