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 brings all the recommended components plus one extra X capacitor (and another extra X capacitor after the rectifying bridge). The MOV is located after the rectification bridge, and not before as usual. And the fuse is located on the first part of the transient filtering stage, i.e., on a small printed circuit board attached to the main AC power plug. This power supply uses a fuse holder, a thing that is rare to see nowadays (most power supplies nowadays come with their fuses soldered directly on the printed circuit board).

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Figure 6: Transient filtering stage (part 1).

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Figure 7: Transient filtering stage (part 2).

In the next page we will have a more detailed discussion of the components used in the Rosewill RD600N-2SB-SL-BK.