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About Electric Resistivity Conversion

Electric resistivity (specific resistance) measures a material's inherent opposition to current flow—resistance normalized by geometry. It's a material property, independent of sample dimensions. While resistance depends on an object's size and shape, resistivity remains constant for a given material under fixed conditions. This distinction is crucial: a long thin copper wire has higher resistance than a short thick one, but both have identical resistivity because they're the same material. Resistivity enables direct comparison of materials' electrical properties regardless of sample geometry.

The SI単位 is ohm meter (Ω·m). Resistivity spans an enormous range: from 10⁻⁸ Ω·m for metals to 10¹⁶ Ω·m for good insulators—over 24 orders of magnitude, one of the widest property ranges in physics. Temperature significantly affects resistivity: metals increase resistivity as temperature rises (due to increased lattice vibrations), while semiconductors typically decrease (more charge carriers are thermally excited). It's the reciprocal of conductivity and essential for electrical engineering, materials science, and semiconductor device design.

Our converter handles all standard electric resistivity units used in wire sizing, material characterization, and electronic design.

Common Electric Resistivity Conversions

Electric Resistivity 単位リファレンス

Ohm meter (Ω·m) – The SI単位 for resistivity, representing the resistance of a 1-meter cube measured between opposite faces. While mathematically correct, Ω·m gives inconveniently small numbers for metals (copper is 1.68 × 10⁻⁸ Ω·m), so practical applications often use derived units. The relationship R = ρL/A connects resistivity to physical resistance, where L is length and A is cross-sectional area.

Ohm centimeter (Ω·cm) – The dominant unit in semiconductor industry specifications. 1 Ω·cm = 0.01 Ω·m. Silicon wafer resistivity is almost always quoted in Ω·cm, ranging from 0.001 Ω·cm (heavily doped) to 10,000 Ω·cm (high-purity intrinsic). Germanium specifications also use Ω·cm. The centimeter scale matches typical wafer dimensions.

Microohm centimeter (μΩ·cm) – The practical unit for metallic conductors where resistivity is very low. Copper ≈ 1.68 μΩ·cm; silver ≈ 1.59 μΩ·cm; aluminum ≈ 2.65 μΩ·cm; gold ≈ 2.44 μΩ·cm. 1 μΩ·cm = 10⁻⁸ Ω·m = 10⁻⁶ Ω·cm. Wire tables and conductor specifications typically use this unit.

Ohm square millimeter per meter (Ω·mm²/m) – The standard wire industry unit, directly relating to wire gauge calculations. Numerically equals μΩ·cm × 10 (so copper ≈ 17.2 Ω·mm²/m). Convenient because wire cross-sections are typically specified in mm² and lengths in meters. Directly gives resistance: R = ρ × L, where L is in meters and ρ is in Ω·mm²/m, yielding R in ohms for 1 mm² wire.

Nanoohm meter (nΩ·m) – 10⁻⁹ Ω·m. Sometimes used for metals to avoid scientific notation. Copper ≈ 16.8 nΩ·m. Less common than μΩ·cm but occasionally seen in physics literature.