The power factor is equal to the cosine of the phase angle. (PF=CosineΦ) Where Φ is the phase angle difference between the voltage and current of an A.C.Power system. Certain loads create a delay of phase shift between the voltage and current. An inductive load (very common), will cause current to lag voltage. DAE JOO's Power Factor Transducer is designed to precisely measure load power factor between the input voltage and input current.