Transient Filtering Stage
As we have mentioned in other articles and reviews, the first place we look when opening a power supply for a hint about its quality, is its filtering stage. The recommended components for this stage are two ferrite coils, two ceramic capacitors (Y capacitors, usually blue), one metalized polyester capacitor (X capacitor), and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil.
This power supply has all required components plus one extra X capacitor and two extra Y capacitors. The MOV is behind the fuse in Figure 8 and thus not shown.
In the next page we will have a more detailed discussion about the components used in the Corsair HX850W.