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.

Even though this power supply has two additional Y capacitors on its transient filtering stage and two additional X capacitors and one additional ferrite coil after the rectifying bridge, it doesn’t have a MOV, which is essential to cut spikes coming from the power grid.

SilverStone Strider ST50F 500 W Power SupplyFigure 9: Transient filtering stage (part 1).

SilverStone Strider ST50F 500 W Power SupplyFigure 10: Transient filtering stage (part 2).

The components used here are identical to the ones used on Zalman ZM360B-APS (and possibly on Zalman ZM460B-APS).

In the next page we will have a more detailed discussion about the components used in the Strider ST50F.


Gabriel Torres is a Brazilian best-selling ICT expert, with 24 books published. He started his online career in 1996, when he launched Clube do Hardware, which is one of the oldest and largest websites about technology in Brazil. He created Hardware Secrets in 1999 to expand his knowledge outside his home country.