In a circuit with unity power factor there is no load harmonic current and there is no shift in the phase relationship between the primary voltage waveform and the load current. The causes of load current phase shift are reactive loads. In the example here, the phase lag is due to an inductive load characteristic. This shift limits the transferrable power and can be compensated with an added capacitor. In the second example of bad power conditions, a low impedance transformer and capacitor bank results in very narrow conduction angle through a rectifier diode. This condition is difficult to correct with passive components and may require the addition of an active power factor filter circuit.