Transient Filtering Stage
Contents
As we have mentioned in other articles and reviews, the first place we look at 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.
In the transient filtering stage, this power supply has all required components, except for the MOV, which is in charge of removing spikes coming from the power grid. Interesting enough, there is a place reserved for an MOV on the printed circuit board.
Figure 9: Transient filtering stage
On the next page, we will have a more detailed discussion of the components used in the Sentey SDP850-SS.
