Understanding Conductor Resistance
Every conductor resists current flow to some degree. Understanding what drives that resistance helps explain voltage drop and how conductor choices affect a circuit.
What determines resistance
A conductor's resistance depends on three things: the material's resistivity, the conductor's length, and its cross-sectional area. Longer or thinner conductors have more resistance; shorter or thicker ones have less.
Resistivity varies by material
Different conductor materials have different resistivity values. Copper has a lower resistivity than aluminum, which is one reason copper conductors are typically smaller than aluminum conductors carrying the same current.
How this connects to voltage drop
Resistance is the link between current and voltage drop: more resistance means more voltage lost over the same length and current. Conductor resistance values are exactly what the Voltage Drop calculators use as an input.