Penti yo nan fòs la oblije chanje se apeprè: rediksyon --- rive sikwi a oblije chanje --- nan wo-frekans AC --- transfòmasyon rive transfòmatè a wo-frekans --- rediksyon, filtraj --- DC. The mains strength we typically use is 50hz, and 50hz AC strength desires to be converted thru a transformer, however the low frequency results in an extended transformer winding, which makes the transformer cumbersome and calls for lots of wires. After turning into a high-frequency alternating current, a exceptionally small transformer may be used to step down, saving value and space.