I watched Helvetica over the weekend, and it must have stimulated that part of my mind that thinks graphically. I had been complaining at work that our new schematic symbol for resistors has seemingly unnatural proportions, but I couldn’t quite put my finger on why. What is “natural” about a resistor symbol?
To try to answer this question, I culled a selection of resistors from a bunch of old schematics I have worked on. These include default symbols from OrCAD, Eagle, Gschem, and Altium. Often you can look at a schematic and immediately identify the tool that was used to create it. That graphic signature is not unlike a font, I think.
The two symbols on the left are the official shapes set forth in IEEE 315-1975 (“Graphic Symbols for Electrical and Electronics Diagrams”), which is the reigning standard in North America (ANSI, CSA, Dept of Defense). Notice how none of the real-world examples seems to reproduce them too faithfully.