Working on a schematic meant for the documentation of a system I'm building (an airsoft prop as a strongpoint for the game).
Since I am using this as a learning experience, I want to really do it as good as possible, even though it's not really needed. I'm working with inkscape designing my own library (originally wanted to use the Wikipedia lib, but I found it lacking in some places, so I pretty much started from scratch).
In schematics in my textbooks, I've run across a few different symbols for rails. I was wondering if there is any difference between these symbols. If so, what does each mean, and what others should I consider. If not, which is preferred? Most of my textbook use the middle symbol (black line with voltage written on top/under it. Positive voltages are labeled as seen here, negative voltages are mirrored horizontally, so the text is under the symbol.)
As a followup question – what is the preferred way to mark bus names in schematics?
I have a bus that is my LCD data, and I would like to label it as such for clarity, but I don't really know what the proper way to do this is. Just write the name above the bus like this?
Best Answer
Really, there is no difference between those symbols. All of them mean the same thing. Any engineer reading the schematic will recognise what each one means. I know sometimes different software gives you different symbols, but I don't think it really matters.
The majority of the time, it is the middle symbol. It is the most common and the one I tend to use. I tend to use the arrows or 'pin' for different nets that aren't a voltage rail, but I am sure other people do it differently.
So to answer your question, use either of them, but if you want to use the one that is used most often, go for that middle one.
For your follow-up question, that is the way I do mine as well. For a bus name, just have it written along the top. Just make sure you have it in a place where you can tell definitely which bus the text belongs to (so don't put it right at a point where 2 separate bus lines run close to each other for example).
I hope this helps!