Inputs in schematic

Could anyone point me to a tutorial or explanation of how to draw inputs to circuits?

I’m very new to drawing schematics. I’m loving KiCad and don’t have any trouble using it. I just don’t know when I should use a Power Flag (and which one?) instead of a Global Label or Net Label or Hierarchical Label… I can certainly get stuff on screen in a way that I understand, but I want to do it the right way for showing other people, simulation, making PCBs (eventually) etc.

Is there a guide to the ‘right way’ to draw schematics?

What have you found so far?
What is your background?

Have you seen those yet?

And as you’re a blank sheet:

  • draw schematics to make the electronic clear to you and any other people who need to understand what the circuit is supposed to do, DO NOT DRAW THE LAYOUT, do abstract!
  • in most cases the top left is input/positive voltage and the top right is output/positive voltage, while the bottom of the page represents ground/negative voltage, the schematic converts the inputs into the outputs and is usually read from left to right, top to bottom

As for labels…

  • local net label is valid on the sheet it’s used, referencing it on another one, won’t connect the nets
  • global is the same for all sheets and will connect all nets with this label
  • hierarchical label connects between hierarchical levels of hierarchical sheets, sort of an intermediary between the global and local labels
  • power flag (

It is common to have an error or a warning on power pins, even though all seems normal. See example above. This happens because, in most designs, the power is provided by connectors that are not power sources (like regulator output, which is declared as Power out). The ERC thus won’t detect any Power out pin to control this wire and will declare them not driven by a power source. To avoid this warning you have to place a “PWR_FLAG” on such a power port.

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We have a nice explanation regarding powerflags in our FAQ

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Thank you! That is all super helpful. I’ve skimmed the links and will read them thoroughly shortly.

One thing I don’t see mentioned that I don’t understand is how one chooses from the dozen or so various Power symbols that could mean a 12V battery positive connection (as an example). There is +12V, VCC, VDD, VBAT, etc. all with arrows, triangles, and circles. Is that simply convention? Personal choice?

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