Any idea what the significance is of the arrow vs the dot?

WBahn

Joined Mar 31, 2012
26,326
The key thing is that it is very poor style to have a wire just end -- this is usually interpreted as an error or oversight. So we use symbols and/or labels to indicate that the wire connects to some other wire somewhere else in the circuit, either on the same page or a different page. These generally fall into two categories: Global signals, such as a common or power supply or bias signal. Because these connect to so many points in the circuit, the drawing would get cluttered beyond reason if we showed them. So we usually try to use a unique symbol or perhaps a non-unique symbol and a label to identify those common nodes. The other are ports where the wires in the circuit on one page (usually input/output signals) connect to wires in the circuit on other pages. This is particularly useful (needed, really) for circuits that are used repeatedly, such as the circuit for a logic gate. We might have dozens of them in our overall circuit but we only want to have one schematic for each type of gate. It is then understood that while each symbol used in other schematics represents the same circuit layout, that each is actually a different copy of the circuit.

As for the actual symbol used -- that really depends on the tool you are using more than anything else. You company or customer may have conventions that they like followed, as well.
 

WBahn

Joined Mar 31, 2012
26,326
I need more context to be sure, but my guess would be that it is simply an easy way to making a symbol that is different in appearance. All wires connected to symbols that appear the same are connected to each other.
 
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