ABSTRACT
As we have learned, ‘power factor’ is defi ned as the ratio of true power to apparent power of a load, and is expressed as the cosine of a circuit’s phase angle – i.e. the cosine of the angle by which the load’s supply current lags or leads its supply voltage. We always express phase angle in terms of the position of the load current, relative to the supply voltage, not the other way around. So,
Power factor can be expressed as ‘per unit’, e.g. ‘0.75 lagging’, or as a ‘percentage’, e.g. ‘75% lagging’. The ‘per unit’ method is more widely used, and expressing it as a percentage is now considered rather old fashioned.
