Electrical Resistance

A wire's resistance is not just a number on a component — it is a shape. Set the metal, length, thickness and temperature and watch R = ρL/A, the conductance and the current at 12 V respond. A longer or thinner wire resists more; a colder or more conductive metal resists less.

Resistance R = ρL ÷ A

0.0336 Ω

ρ(T) = 1.68 × 10^-8 Ω·m

At a fixed 12 V supply G = 1/R · I = V/R

Conductance G

29.76 S

Current I at 12 V

357.1 A

Material

Length L2.0 m

Cross-section A1.00 mm²

Temperature T20 °C

Supply fixed at V = 12 V · A converted from mm² (×10^-6) to m² · ρ(T) = ρ₂₀(1 + α(T - 20))

Try it: a thicker wire (bigger A) lowers R — thickness helps charge flow, it doesn't obstruct it.