Give a man a fish and he eats for a day. Show him how to fish and he
can feed himself for life.
Copper has a resistivity of 10.371 ohms at 20 degrees C. The inferred
resistance is zero ohms at -234.5 degrees C. Now apply the point
slope formula to find the equation between the two points and you can
find the resistance at any temperature.
For Aluminum the resistivity is 17.002 ohms at 20 degrees C and the
inferred resistance is zero at -228.1 degrees C.
Resistivity is the resistance of material one foot long and 0.001 inch
in diameter or one circular mil in cross sectional area (diameter in
thousands of an inch squared)
Resistance is inversely proportional to circular mil area. Divide
resistivity by CMA to find resistance of larger conductors.
Reference: Neher McGrath paper where RDC is discussed. N-G also uses
a lay factor 1.02.
Whoever said that never tried to teach a real person how to fish or
learned from a real person. Sure,when fish are plentiful, like when a
fish hatchery mistakenly realized their stock of fish, it is easy. When
fishing is tough, the good fishermen were the ones born that way. They
were not made by fishing schools.
So do not teach. Do not give any fish.
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