A schematic diagram refers to a specific type of circuit diagram that utilizes standard electrical/electronic symbols rather than images to demonstrate the way the circuit (or portion of it) works. Below is a normal 3-wire motor controller circuit utilizing a normal momentary stop - start pushbutton station utilizing a schematic diagram. (Momentary here means that the button/switch you trigger will go back to its default position once you physically let go of this, usually by a spring that forces the button/switch to get this done.)
Following is a specialized version of a diagram known as a ladder diagram. The principal point of this diagram is to show the logic (referring to electrical control) of a circuit. This diagram is the one that I mostly encounter in my line of work, and it is very effective for troubleshooting issues or learning the way the circuit works. Some circuits are so enormous that most types of schematic diagrams need to be recorded in increments from book form (normally with coded numbers so that information can be simpler found). Again, here's the identical specific circuit because the first 2, however, considering it in ladder shape.
Pictorial schematic diagrams, or pictorial circuit diagrams are essentially the identical thing with the identical purpose, however they use images of components within the circuit instead of symbols. Again, here is the exact identical exact circuit (almost except a controller was added and they're utilizing conductors L1 and L3 instead of L1 and L2.
Right, Less clutter? I have enough info in each of these diagrams to know just what this circuit does and where to start looking for issues. Hope that this helps. ( Note: do not confuse circuit or schematic diagrams together with wiring diagrams; wiring diagrams will typically show pictures of components such as the pictorial, and the way the whole or portion of a circuit will be wired. The distinction is that wiring diagrams typically place an emphasis on actual physical location of necessary components relative to each individual that basically tell a layman Just What to do concerning the wiring)
Think of it this way; a circuit structure is any type of diagram that illustrates how a circuit operates where the major objective is that the proper wiring of components and their connection to each other rather than physical location relative to one another or planning prototypes. Nonetheless, in some uses classifying diagrams can be challenging so do this as overall information. I have found this is especially true when dealing with much more complicated circuits and electronic equipment. I'm going to work with a more straightforward but typical industrial circuit because these circuit set ups are the exact same, but nevertheless where it is possible to see how each sort of diagram shows the use of the circuit in their own ways.
Here is another schematic diagram demonstrating exactly the identical circuit, connections and components and it looks different but they fall into the identical category.