Logisys PS600A12 Power Supply Review

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. 

In the transient filtering stage, the Logisys PS600A12 has all the required components, including one additional X capacitor, but it doesn’t have the MOVs. There is space for installing two MOVs between the electrolytic capacitors of the voltage doubler circuit, but the manufacturer decided not to add them.

Figure 8: Transient filtering stage (part 1)

Figure 9: Transient filtering stage (part 2)

In the next page we will have a more detailed discussion about the components used in the Logisys PS600A12.