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      1, the power factor (PF): power factor is the cosine of the phase difference between voltage and current values. Because the current and voltage are the wave of FIG, is a sinogram, a cosine; FIG difference waveform by two 1/4 cycles (i.e.: 90 °), thus forming a PF value, in order to increase the PF value, to a correction in the power supply circuit, a high PF value is also relatively high cost of power. PF correction circuit without PF value is generally about 0.6, with PF basic circuit can reach 0.9, or even higher.

PF value is low when on the entire power system grid pollution, when the PF value is low, the electrical equipment for power generation efficiency becomes low, so the state for some big power with PF value of electrical equipment requirements, general it would be no less than 50W clear requirements. PF value state requirement is more than 0.6.

2, conversion efficiency: the popular talk is the output power and input power ratio, such as: a 10W electric power consumed by a lamp, but only 8W electric power is used to shine (also known as: useful work), but also with 2W in the supply of electric power on the heat loss out of the device (also known as: useful work), the power conversion efficiency of the lamp Zhezhi is 80%.