Transient Filtering Stage

As we mentioned on other articles, 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 than that, usually removing the MOV, which is essential for cutting spikes coming from the power grid, and the first coil.

Even though this power supply from Zalman has more components than the necessary – one extra X capacitor, two extra Y capacitors, one extra coil and a ferrite bead on the main power cable –, it doesn’t have a MOV, which is a sin for a power supply from this category.

Zalman ZM600-HPFigure 12: Transient filtering stage (part 1).

Zalman ZM600-HPFigure 13: Transient filtering stage (part 2).

A very interesting feature from this power supply is that its fuse is inside a fireproof rubber protection. So this protection will prevent the spark produced on the minute the fuse is blown from setting the power supply on fire.

This section is identical to the one found on OCZ StealthXstream 600 W and GameXstream 700 W.

In the next page we will have a more detailed discussion about the components used in the ZM600-HP.


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.