Consider it in this way; a circuit diagram is any type of diagram that demonstrates the way the circuit operates where the primary goal is that the appropriate wiring of elements and their connection to each other rather than physical location relative to each other or intending prototypes. Nonetheless, in some applications Assessing diagrams can be challenging so choose this as general information. I have found this is especially true when dealing with much more complicated circuits and electronics. I'm going to use a more straightforward but average industrial circuit since these circuit set ups are the exact same, but where it is possible to see how each kind of diagram indicates the operation of the circuit in their own ways.
Pictorial design diagrams, or pictorial circuit diagrams are basically the identical thing with exactly the same function, but they use pictures of elements inside the circuit instead of symbols. Again, here's the same exact circuit (virtually except a control transformer was inserted and they're utilizing conductors L1 and L3 rather than L1 and L2.
Here is a variant of a diagram. The major intent of this diagram is to show the logic (referring to electric control) of a circuit board. This diagram is the one I mostly come across in my line of work, and it's extremely effective for troubleshooting problems or learning the way the circuit functions. Some frequencies are so huge that most kinds of schematic diagrams need to be recorded in increments from book form (usually with coded numbers so info can be simpler found). Again, here is the identical specific circuit as the first 2, however, looking at it in ladder shape.
A design diagram refers to a specific kind of circuit structure which uses standard electrical/electronic symbols rather than pictures to show how a circuit (or portion of it) works. Below is a standard 3-wire motor control circuit employing a normal short stop stop - start pushbutton channel using a schematic diagram. (Momentary here means that the button/switch you activate will return to its default place once you physically let go of it, typically by a spring which forces the button/switch to do this.)
Less clutter, right? I've got enough information in each one of these diagrams to know just what this circuit does and where to look for problems. Hope that this helps. ( Note: do not confuse lecture or circuit diagrams with wiring diagrams; wiring diagrams will usually show images of components such as the pictorial, and also how the whole or portion of a circuit is wired. The distinction is that wiring diagrams usually place an emphasis on real physical location of necessary elements relative to each individual that basically tell a layman Just What to do concerning the wiring. )
Here's another schematic diagram showing exactly the same circuit, components and connections and it appears different but they both fall into exactly the identical category.