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Manufacturers : Power supplies : EMI and RFI filters
All electromechanical equipment create electromagnetic interference or "noise" on their power lines. Electromagnetic interference (EMI) or electrical noise disrupts the normal operation of electronic equipment such as power supplies, electromechanical devices and computer systems. The noise can be generated by load transients, switching power supplies or PWM inverters. Such noise can adversely affect the performance of other equipment that receive power from same power lines. For a computer system, such an electromagnetic disruption may be caused by its external cabling, power supplies, electronic components, signal transmission paths, printed circuit boards and the like. A power supply unit is essential to almost every electric appliance and always become a main source of electromagnetic interferences. For this reason, most power supply devices are provided with an electromagnetic interference filter (EMI filter). In order to prevent electromagnetic waves from entering into or being radiated from an electronic apparatus by way of an electric wire connected to the electronic apparatus, an EMI prevention filter is mounted on the electric wire. In the electronic apparatus, an electromagnetic interference suppression filter is installed intermediately in the electronic circuit in order to obviate the occurrence of malfunction due to noises induced by the power source line or the signal line and to prevent the noise originating in the apparatus from affecting other equipment. A typical EMI filter includes an input and output series transformers and a shunt transformer coupled to ground, this transformer combination being configured so that the overall effect is the attenuation of the common-mode electrical noise. Electromagnetic interference in the frequency range is commonly referred to as radio frequency interference (RFI). Radio frequency interference is unwanted electrical energy in the frequency range generally used for radio communications. RFI can occur in a telecommunications network whose wiring is subject to strong radio frequency electrical fields. Current RFI is propagated by radiation (electromagnetic waves in free space) and by conduction over signal lines and AC power systems. Video signal processing systems, such as television receivers, are increasingly using digital processing and digital control techniques. The digital control signal for both monaural and stereo sound systems, including those for TV receivers, are typically passed through both radio frequency interference (RFI) and low pass filters before being applied to the circuit being controlled.

Listings on Power supplies : EMI and RFI filters

  • California Micro Devices Corporation
    Supplier of low-capacitance ESD protection arrays, AC signal ESD protection devices, Zener-clamped ESD protection arrays, transient voltage protection arrays, chip-scale ESD protection arrays, EMI filters, combined function EMI+ESD protection devices, IEEE1284 ECP/EPP terminators, USB transceivers, USB port terminators, CompactPCI backplane interfaces, keypad multiplexers, K7 Athlon VID/FID interface, keyboard/mouse filters and ESD protectors, VGA port ESD protectors and terminators, clock terminators, bussed and isolated resistor arrays, DTMF transmit/receive circuits, microphone amplifiers, and keypad multiplexers. USA.
    http://www.calmicro.com
  • Dearborn Electronics, Inc.
    Manufactures film and paper capacitors, ceramic EMI filters and other allied components for the aerospace, defense, power electronics and other electronics industries. Products include polyester film capacitors, polypropylene film capacitors, energy storage capacitors, polyphenylene sulfide film/foil capacitors, high current and high voltage power capacitors, feed through capacitors, EMI filters, EMI / RFI subminiature ceramic filters. USA.
    http://www.dei2000.com
  • EMI-Shielding Technology
    Specializes in the research and development of soft electromagnetic shielding materials and shielding fabrics. Their shielding fabrics are coated with nickel copper on woven, non-woven, ripstop and taffeta fabrics, and are y used to produce shielding tape or gasket. And also used for making shielding garments, ESD (electric static discharge) gamemts and packing materials, shielding tents and shielding rooms. China.
    http://www.emishielding.com.cn
  • ETS-Lindgren
    Supplier of shielding solutions for electromagnetic and radio frequency interference. Specializes in the design and manufacture of electromagnetic shielded enclosures, single circuit filters, EMP and HEMP filters, common mode and differential mode filters, custom filters, and commercial filters. USA.
    http://www.lindgrenfilters.com
  • Intermark USA, Inc.
    Provides a wide range of ferrite products for the EMI suppression, cable shielding materials, grounding fasteners and conductive gaskets. Other product line segments include a complete selection of plastic fasteners and hardware for the electronic packaging, optical fiber inspection equipment and thermal management components.
    http://www.intermark-usa.com
  • LCR Electronics, Inc.
    Specializes in design, development and manufacturing of custom and standard EMI filters (RFI filters, EMC filters), EMC solutions, motor controls, electronic controls, subsystem enclosures and back planes. Also supply Wire harness & cable assemblies, suppression coils, chokes & inductors and a full range of capacitors including approved X&Y capacitors, DC capacitors (for electronics) and motor run capacitors. USA.
    http://www.lcr-inc.com
  • Murata Manufacturing Company
    Manufacturer of monolithic ceramic capacitors, ceramic filters, ceramic resonators, surface acoustic wave filters, multilayer ceramic devices, dielectric filters, isolators, circuit modules, power supplies, EMI suppression filters, sensors, coils, thermistors, trimmer potentiometers, resistor networks, high voltage resistors and other products. Japan.
    http://www.murata.com
  • ProTek Devices
    Manufacturer of transient voltage suppression (TVS) products designed specifically for the protection of electronic systems from the destructive effects of lightning, electrostatic sischarge (ESD), nuclear electromagnetic pulse (NEMP) and inductive switching. Products include EMI filter TVS arrays, flip chip TVS arrays, steering diode arrays, and thyristors. USA.
    http://www.protekdevices.com
  • RME Filters, Inc.
    Supplier of electromagnetic interference (EMI) filters, RF and microwave components, including electromagnetic interference (EMI) filters, military-grade filters (designed and tested to MIL-F-15733), signal line filters for multiple circuit applications, power input filters for equipment, subsystems and power supplies, facility filters, tubular filters for feed-through performance to 10GHz, filter assemblies, and RLC networks. USA.
    http://www.rmefilters.com
  • SAE Power
    Manufacturer of switching power supplies, magnetic components, EMI/RFI line filters, and electronic sub-Assemblies. Products include general purpose line filters, power entry modules, medical application line filters, PCB mount line filters for DC bus architectures, 3-phase AC input line filters, 1U high hot-swap / redundant power supply modules (800-2100 Watts),1U high hot-swap / redundant power shelves (2400-6300 Watts), and general purpose AC/DC power supplies (230-600 Watts). USA.
    http://www.saepower.com
  • Spectrum Control, Inc.
    Designer and manufacturer of control products and systems used to condition, regulate and govern electronic performance. Products include low pass EMI filters, surface mount EMI filters, filtered arrays, filtered connectors, specialty ceramic capacitors, motor line feed-thru filters, power line filters, power entry modules, multisection filters, power terminal blocks, and custom power filter assemblies, power distribution units, remote power management and monitoring systems, fuse interface panels, breaker interface panels, custom power distribution systems, ceramic resonators and bandpass filters, ceramic patch antennas, duplexers, lumped element filters, cavity filters, waveguide filters, and related products and systems.
    http://www.spectrumcontrol.com
  • Tusonix, Inc.
    Manufacturer of ceramic EMI/RFI electronic components, including EMI/RFI feed-through filters, surface mount EMI filters, ceramic variable trimmer capacitors, custom filter/capacitor assemblies, filtered terminal blocks, radial leaded disc, tubular and plate capacitors. USA.
    http://www.tusonix.com
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