I need to show a few parasitic series resistors in my schematic. Is there a good way to distinguish these from intentional resistors, so it is easy to tell which is which?

Parasitic capacitors are a bit easier to do this since they are parallel parasitics and can have their leads shown in dotted lines, e.g. here as shown from Wikipedia:

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    \$\begingroup\$ dashed line works for me \$\endgroup\$ Sep 8, 2016 at 17:42
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    \$\begingroup\$ I would draw them as resistors and indicate their nature in the reference designator, with an explanatory note, "RP1 to RPnnn are parasitic resistances, not physical components." \$\endgroup\$
    – user16324
    Sep 8, 2016 at 17:42
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    \$\begingroup\$ and/or draw a dashed rectangle around them? \$\endgroup\$
    – Wesley Lee
    Sep 8, 2016 at 17:43
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    \$\begingroup\$ @Brian's method is the one most often used, in my experience. Give them names like Rline (or Lwire for series inductance) and note what they are. \$\endgroup\$ Sep 8, 2016 at 17:48
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    \$\begingroup\$ If you expect someone in the future to read this schematic, put it in words on the schematic. There are plenty of "what does this schematic symbol mean" questions posted here; anything outside the normal basic sch symbols will be hard to decode. Do yourself a favor and explain in a note on the schematic. Example: "Note 1: Rline models resistive drop across input wiring harness". Best if the words can be close to the reference, but if not, put a ( 1. ) at the site and Note 1 off in the corner of the same sheet. \$\endgroup\$
    – MarkU
    Sep 8, 2016 at 20:57

1 Answer 1


I normally draw a dashed line around the component and label differently to other components.

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