- Line filter
A line filter is the kind of
electronic filter that is placed between an electronic equipment and a line external to it, to attenuate conducted radio frequencies -- RFI, a.k.a.electromagnetic interference (EMI) -- between the line and the equipment.In particular, an AC Line Filter is used between the AC power line and the equipment.
Types of line filters
* A Line Filter may be incorporated in a connector. For example:
** An AC Line Filter may be incorporated in a modular IEC power inlet connector or Power Entry Module
** A telephone line filter may be incorporated in a modular RJ11 connector
* A line filter may be mounted on a PCB
* An AC line filter may be a stand-alone device, chassis mounted inside the equipment
* A facility AC Line Filter is mounted inside a room or cabinet, at the point where the AC power comes inCharacteristics of line filters
* A line filter may be used to attenuate EMI in either direction. For example:
** Emissions: It may be used to reduce the unintentional conducted emission from the equipment, to a level sufficiently low to pass regulatory limits (such as FCC part 15). For example, in switching power supplies.
** Immunity: It may be used to reduce the level of EMI entering the equipment, to a level sufficiently low not to cause any undesired behavior. For example, in equipment used in Radio Transmitter facilities* The attenuation of Line filters is measured in 2 areas:
** Common Mode - attenuation to signals that an appear identically on each of the wires going through the filter
** Differential Mode - attenuation to signals that appear on just one of the lines
* For each Mode, the attenuation is characterized over the frequency spectrum, and measured in dBReferences
* [http://www.induktor.co.id/ PT.Induktorindo Utama] Manufacturer of inductive components (transformer, coil, inductor, etc)
* [http://www.schaffner.com/ Schaffner EMC] Manufacturer of EMI filters
* [http://www.elect-spec.com/isofltry.htm Electronic Specialists] Application notes
* [http://cor.com/ Corcom] Manufacturer of stand-alone filters and filtered power entry modules
* [http://www.qualtekusa.com/ Qualtek] Manufacturer filtered power entry modules
* [http://www.schurterinc.com// Schurter] Manufacturer EMI filters and filtered power entry modules
* [http://www.panasonic.com/industrial/components/components.html Panasonic] Manufacturer of PCB level filters
* [http://www.epcos.com/ Epcos] Manufacturer of PCB level filters
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