Power Line Filters

Power line filters have active filtering and passive filtering for its filter circuits. There is only one form of active filtering: electronic filters or active RC filtering. Passive filtering, on the other hand, has complex filtering, inductive filtering, and capacitive filtering.

Characteristics

Power line filters’ attenuation have two measured areas – differential mode for signals that come out on only one of the lines, and common mode, for signals that are similar or identical on every line passing through the filter.

Power line filters are utilized in attenuating EMI in two directions – immunity and emissions. Immunity is for decreasing EMI to low levels to avoid unwanted behavior. Emissions are for reducing unintentional conducted emissions to a sufficiently low level so they can pass regulatory limits. Radio transmitter facilities and switching power supplies are examples of immunity and emissions; respectively.

Types

There are four types of power line filters: PCB-mounted, cabinet or room-mounted, connector-incorporated, and stand-alone.

• PCB-mounted refers to printed circuit board-mounted power line filters.
• Power line filters may also be mounted or placed inside a cabinet or room, in an area where the AC power line is.
• A power line filter can also be incorporated into a connector, like telephone line filters that are in an RJ11 connector.
• Stand-alone power line filters are equipped with a mounted chassis.