Ohm (Ω)

Quantity: Electrical resistance · Category: Derived SI

The ohm is the SI unit of electrical resistance: the resistance that lets one ampere flow under one volt. It is named after Georg Ohm, whose law V = IR defines the relationship.

Relation to SI

1 Ω = 1 V/A = 1 kg·m²/(s³·A²)

Examples

• A typical headphone driver is about 32 ohms.
• Copper household wire is a tiny fraction of an ohm per meter.