> just plain wrong -- e.g. floating inputs or missing resistors TTL logic gates have no problem with floating inputs. Those are interpreted as logic high. [1]

> just plain wrong -- e.g. floating inputs or missing resistors TTL logic gates have no problem with floating inputs. Those are interpreted as logic high. [1] This is fairly self-evident from looking at a typical TTL gate schematics. [2] Some "TTL-compatible" CMOS parts (including 65C02) have internal pull-ups on inputs, to match this quirk. [3] Granted, it is a bad habit to develop, given that nearly all "modern" logic (i.e. of past 30+ years) is CMOS with no "TTL compatibility", and floating inputs are a big problem there. [1] https://electronics.stackexchange.com/questions/683051/output-of-a-logic-gate-when-its-inputs-are-floating https://electronics.stackexchange.com/questions/683051/outpu... [2] https://upload.wikimedia.org/wikipedia/commons/thumb/d/d4/TTL_npn_nand.svg/2499px-TTL_npn_nand.svg.png https://upload.wikimedia.org/wikipedia/commons/thumb/d/d4/TT... [3] https://wilsonminesco.com/NMOS-CMOSdif/ https://wilsonminesco.com/NMOS-CMOSdif/