The ideal power factor occurs when the current and voltage waveforms are in phase, giving a power factor of 1 as highlighted in the first diagram. Problems occur, however, when a non-linear load on a power system, typically in the form of a power supply, creates current harmonics not present in the voltage. In effect, these current harmonics become part of the reactive power. They do not represent true power delivered to the load, but they do degrade the power factor. This is highlighted in the second diagram.