• Aceticon@lemmy.world
    link
    fedilink
    English
    arrow-up
    4
    ·
    edit-2
    6 months ago

    In the design and manufacture of PCBs (aka circuit boards) a “mil” is a one thousandth of an inch, so it makes sense that’s what is being used in this context.

    Also the maths check out: 0.005 inches is equal to aprox 0.12mm, “just over 0.1mm”.

    • flying_gel@lemmy.world
      link
      fedilink
      English
      arrow-up
      2
      ·
      6 months ago

      I stand corrected, and I see I didn’t read the comment thoroughly enough either.

      Colloquially as a non-pcb maker I would use and hear the term “mill” as short form millimeter so I assumed it was that.

      so TIL :)

      • Aceticon@lemmy.world
        link
        fedilink
        English
        arrow-up
        3
        ·
        6 months ago

        Yeah, I found it wierd too when I started designing PCBs (as hobby) that “mill” actually stood for thousanth of an inch.

        Probably for historical reasons, there are tons of things in the older domains within electronics that are based on inches rather than metric units: for example the spacing between the legs of a microchip in the older chip package formats (so called DIP, the ones with legs that go into holes) is exactly 0.1"

        The sizes in more modern electronics isn’t usually based on inches anymore, but circuit boards are old tech (even if done with new materials) so there are still a number of measures in there which are based on inches.