The solution to excess harmonics is to use power factor correction, which shapes the input current of the PSU to maximize the real power level from the mains and minimize harmonic distortion. This corrected waveform minimizes losses as well as interference with other devices being powered from the same source. Power factor correction techniques can be defined as passive or active. Both design schemes present tradeoffs, so designers must take into account regulatory constraints while also addressing the pressures to meet space, component bill-of-materials, and efficiency targets.