Send Message
Home > news > Company news about What is EMI/RFI filter?
Contact Us
Contact Now

What is EMI/RFI filter?


Latest company news about What is EMI/RFI filter?

EMI filter also called RFI filter is an electrical device/circuit. Can reduce the high-frequency electromagnetic noise on a power line and signal line. This noise is typically in the 9KHz to 10GHz frequency range. And it can degrade or prevent the signal transmissions and/or the intended performance of electrical/electronic equipment. The lower frequency components of the EM noise can impact the power quality as well.


The high-frequency noise is generated by a variety of electrical and electronic devices such as electronic controls, motors, power supplies, clock circuits, inverters, appliances, microprocessors, electronic devices, etc.


3 Phase EMI Filter

Single Phase RFI Filter

EMI Power Filter


EMI/RFI Filter Applications:


Our selection of EMI/RFI power line filters includes single-phase filters and three-phase filters in an assortment of styles and configurations to meet your specific requirements.


Our EMI/RFI filters are assembled, designed, and tested to ensure the best quality and performance for any power line application, including:



Linear power supplies Medical directive Modems
Systems with switching power supplies Surge protection Hard-disk systems
SMPS with on-board filter Microprocessors Computers
Machinery directive Digital test equipment Data terminals
  Transient suppression Process control equipment


YBX unmatched design capabilities, innovative solutions, and dedication to customer satisfaction guarantee the highest quality EMI filters for your needs. Our RFI/EMI filters are the best choice for superior power line filter safety, design, and performance.

What is EMI/RFI?


EMI (Electromagnetic Interference) is also called RFI (Radio Frequency Interference). EMI and RFI are the radiation or conduction of radiofrequency energy (or unwanted electronic noise) produced by electrical and electronic devices at levels. That interferes with the operation of adjacent equipment. Frequency ranges of most concern are 10kHz to 30MHz (conducted) and 30MHz to 1GHz (radiated).


Although the terms EMI and RFI are often used interchangeably. EMI is actually any frequency of electrical noise, whereas RFI is a specific subset of electrical noise on the EMI spectrum.


What Causes EMI/RFI?


The most common sources include components such as switching power supplies, relays, motors and tracks. These devices are found in a wide variety of equipment used in industrial, medical, white goods, and building HVAC equipment.


What are the Types of EMI | RFI?

  • Conducted RFI is released from components and equipment through the power line cord into the AC power line network. This conducted RFI can affect the performance of other devices on the same network.
  • An Electrical or Electronic Device Emits RFI in Two Ways: Radiated RFI is emitted directly into the environment from the equipment itself.

What are the effects of EMI/RFI on your electrical system?


If you are occasionally experiencing interference with your telephone system, flickering computer monitors, reliability issues with computer networks, instrumentation errors, or misbehaving electronics you are most likely experiencing EMI/RFI in your electrical environment. EMI/RFI can wreak havoc with your electronics, computers, and telephones, making your workplace difficult to work in. Since most machines have control electronic circuits, they may become difficult to control or unreliable.


How do you reduce the effects of EMI/RFI?


Depending on your application, there are many ways to reduce the effects of EMI/RFI. For conducted EMI/RFI, you can choose from a large range of EMI/RFI filters.


What are the Circuit Configurations of EMI | RFI Filters?


Typical types of EMI | RFI filters are designed for a specific type of signal and the devices in which they will be installed. The wide variation in devices and equipment that benefit from EMI filtering necessitates a range of standard solutions, as well as an expanse of customization capabilities. The following are a few types of EMI | RFI Filters.


Three-Phase Filters


Three-phase filters are similar to single-phase filters except that the filter is designed to filter three signal/power lines for three-phase power and motor systems. There are some three-phase filters that also include filtering on the neutral line for applications that require it. Three-phase filters are useful as main input filters for industrial equipment, machine tools, machinery and automation systems. Depending on the leakage performance of a filter, they may even be used with some medical devices and equipment.


Single-Phase Filters


A single-phase EMI | RFI power line filter is designed for AC or DC power lines with a positive or negative, or dual, signal/power path. This type of filter is installed in line with the power/signal lines, allowing DC and AC signals to pass without attenuation, while heavily attenuating signals from 10kHz to 30MHz. These types of filters are used in single-phase motor drives, power supplies, office equipment, and test and measurement equipment, amongst other applications. Some single-phase filters are optimized for specific applications, such as their DC performance, medical equipment requirements, industrial safety requirements, and other standards.


DC Filters

DC filters are designed specifically for filtering DC power and control lines. This could be for protecting solar panels, photovoltaic charging/converting systems, battery charging and conditioning systems, DC motor drives and inverter/converters. Though similar to AC EMI | RFI filters, DC EMI | RFI filters are optimized for passing only DC signals and are typically rated for higher DC voltages and currents. These filters are useful in preventing premature aging and protection of solar panels due to conducted emissions, such as HF stray and leakage currents.


Consisting of a multiple-port network of passive components arranged as a dual low-pass filter, the EMI/RFI filter attenuates radiofrequency energy to acceptable levels, while permitting the power frequency current to pass through with little or no attenuation. Their function, essentially, is to trap noise and to prevent it from entering or leaving your equipment. Selection of the most suitable EMI/RFI power line filter can best be based on the type of power supply or the input impedance of the equipment and the mode of the offending EMI/RFI noise.

Send your inquiry directly to us

Privacy Policy China Good Quality EMI Power Filter Supplier. Copyright © 2019-2024 . All Rights Reserved.