What is an EMI / EMC Filter?

EMI /EMC filters or power line filters are electronic devices used in electronic circuits and devices to mitigate or filter out conducted electromagnetic interference (conducted EMI).  Conducted EMI refers to high-frequency noise currents (or voltages) generated during electrical and electronic device working that travel through power lines, cables, PCB traces, and other electrical connections. These noise currents (or voltages) have the potential to disrupt the normal operation of other connected electronic devices and systems.
Conducted EMI may be generated within the electronic device itself (due to the switching of electronic components, such as transistors), and/or it can be generated from external sources/ devices (due to the operation of other connected nearby electronic devices, motors, or other equipment).  The primary function of the EMI /EMC filters is to suppress or filter out the conducted EMI, thereby ensuring electronic equipment's reliable operation.  

How does an EMI/EMC filter work?

An EMI/EMC filter typically consists of passive components such as capacitors, inductors, and resistors arranged in a specific configuration. Basically, this filter works as a low-pass filter that filters out high frequencies while allowing lower frequencies to pass through. The EMI/EMC filter is inserted or placed in between the power supply line and an electronic device. This filter effectively diverts high-frequency noise currents away from the device to be protected, either by diverting the currents to the ground or, in some cases, absorbing them.
In this way, the EMI/EMC filter prevents conducted EMI on the power line from entering the equipment (thereby protecting the equipment from external noise currents or disturbances) and also prevents the conducted EMI generated within a device from reaching the input power line (thereby protecting the other connected devices from the internal noise currents).
By controlling the conducted EMI onto the power cord, a power line filter or EMI filter also contributes to significantly reducing radiated EMI caused by conducted EMI. These filters play a crucial role in electronic device design by addressing both internal and external electromagnetic interference issues, ensuring compliance with EMC regulatory standards, and enhancing the overall performance and reliability of electronic equipment.

EMI/EMC filters applications:

The EMI/EMC filters are ideal for use in motor drives, wind turbines, power supplies, autonomous machines, home appliances, DC power distribution, audio and video equipment, medical equipment, military equipment, and more.

EMC Directory has listed EMC/EMI Filters from the leading manufacturers. View product details, download datasheets and get quotes on products that meet your requirements.