The conventional switching power supply usually use a diode rectifier followed by a bulk capacitor to convert ac voltage to dc voltage , resulting in the pulsating waveform of the input ac line current , low power factor ( generally 0 . 65 ) and high harmonic line current 傳統(tǒng)的開關電源設備通常采用二極管橋來進行整流和一個較大的電解電容來進行濾波以實現(xiàn)輸入電壓的交直流轉(zhuǎn)換,導致輸入電流為一個很窄的脈沖波并含有較多的諧波分量,功率因數(shù)變低(通常只有0 . 65 ) 。