Power Factor
The ratio of real power dissipated by an AC circuit to the apparent power delivered by the supply.
Governing formula
PF = cos φ = P_real / S_apparent = R / Z
SI unit
Dimensionless (0 to 1)
In depth
Phase angle φ between AC voltage and current reduces real work delivered. Purely reactive inductive or capacitive circuits have a power factor of zero.
Examples in the real world
Industrial factories installing parallel capacitor banks to correct inductive motor power factors closer to unity (PF ≈ 1.0).