I wouldn't expect useful accuracy from anything but a lab instrument for such low resistances as a few feet of #12. Far better to look up the resistance of copper wire from a wire table. An unknown "black box" like a power strip is not so easy. :) As for the protection diode, that's pretty easy too -- look up the junction voltage for that type of diode, and you're within 0.1 volt of reality.

The thing I find baffling (or depressing) here is that we all had to understand Ohm's Law to pass the exam for our license, and it's REAL simple. Take resistance values from a wire table, multiply by the length, then by two for the two conductors, then by the current. I dunno what the exam is like nowadays -- my experience was 1955 with the Novice test and a year later with the General -- but surely there must be something about how diodes work!

73, Jim K9YC


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