Pictorial design diagrams, or graphic circuit diagrams are basically the same thing with exactly the identical purpose, however they use pictures of elements within the circuit rather than symbols. Again, here is the identical exact circuit (virtually except a control transformer was inserted and they are utilizing conductors L1 and L3 rather than L1 and L2.
A design diagram refers to a specific kind of circuit diagram that uses standard electrical/electronic symbols rather than pictures to demonstrate how a circuit (or a portion of it) works. Below is a typical 3-wire motor control circuit employing a normal momentary stop - start pushbutton channel using a schematic diagram. (Momentary here means that the button/switch you trigger will go back to its default position once you let go of this, usually by a spring that forces the button/switch to do this.)
Think of it this way; a circuit diagram is any sort of diagram that illustrates the way the circuit functions where the principal goal is the proper wiring of components and their relationship to each other rather than physical location relative to each other or planning prototypes. Nonetheless, in some uses classifying diagrams can be difficult so choose this as general advice. I have found this is especially true when dealing with more complicated circuits and electronics. I'm likely to use a simpler but average industrial circuit because these circuit set ups are the exact same, but where it is possible to observe how each kind of diagram shows the function of the circuit in their own manners.
Here is another schematic diagram showing precisely the identical circuit, components and connections and it appears different but they fall into precisely exactly the same category.
Less mess? I've got enough info in every one these diagrams to know just what this circuit does and also where to look for issues. Hope this helps. ( Note: do not confuse circuit or schematic diagrams together with wiring diagrams; wiring diagrams will typically show images of components like the pictorial, and also the way the whole or part of a circuit will be wired. The difference is that wiring diagrams usually put an emphasis on actual physical place of necessary components relative to each other that basically tell a layman exactly what to do concerning the wiring)
Here is a version of a diagram called a ladder diagram. The primary point of this diagram is to show the logic (referring to electrical control) of a circuit board. This really is the one that I mainly come across in my own line of work, and it's very effective for troubleshooting issues or learning how a circuit works. Some frequencies are so enormous that many kinds of schematic diagrams need to be read in increments in novel form (normally with coded numbers so that information can be easier located ). Again, here is the same exact circuit since the first 2, but looking at it in ladder shape.