A design diagram refers to a particular type of circuit diagram which utilizes standard electrical/electronic symbols rather than images to show how a circuit (or portion of it) works. Below is a normal 3-wire motor control circuit employing a typical momentary stop - start pushbutton station working with a schematic diagram. (Momentary here means the button/switch you activate will return to its default location once you let go of this, usually by a spring that compels the button/switch to do this.)
Following is a specialized variant of a diagram. The main intention of this diagram is to show the logic (speaking to electric management ) of a circuit board. This diagram is the one that I mostly come across in my own line of work, and it's extremely effective for troubleshooting issues or learning the way the circuit functions. Some frequencies are so huge that many kinds of schematic diagrams need to be read in increments in novel form (typically with coded numbers so that info can be simpler found). Again, here's the exact precise circuit since the first two, but considering it in ladder type.
Think of it this way; a circuit structure is any type of diagram which demonstrates how a circuit functions where the main goal is the appropriate wiring of elements and their connection to each other instead of physical place relative to one another or planning prototypes. However, in some uses classifying diagrams can be hard so accept this as general advice. I've found this is especially true when dealing with much more complex circuits and electronic equipment. I'm likely to work with a simpler but average industrial circuit since these circuit setups are exactly the same, but where you can see how each kind of diagram shows the operation of the circuit in their own ways.
Much less clutter? I've got enough info in each one of these diagrams to know exactly what this circuit will do and where to look for problems. Hope this helps. ( Note: do not confuse lecture or circuit diagrams with wiring diagrams; wiring diagrams will usually show images of elements like the pictorial, and also the way the entire or portion of a circuit has been wired. The difference is that wiring diagrams usually place an emphasis on real physical location of necessary components relative to each other that essentially tell a layman exactly what to do about the wiring. )
Pictorial schematic diagrams, or pictorial circuit diagrams are basically the identical thing with exactly the exact identical purpose, however they use pictures of elements within the circuit instead of symbols. Again, here's the exact specific circuit (almost except a control transformer was included and they are utilizing conductors L1 and L3 rather than L1 and L2.
Here is another schematic diagram demonstrating precisely exactly the same circuit, connections and components and it looks different but they fall into the identical category.