What is an EMI Filter?

8th March 2016

What is an EMI Filter?

EMI stands for Electro Magnetic Interference and an EMI filter is a vital part of any piece of electronic equipment. They are either a separate device or they are embedded into the circuit boards. An EMI filter, is an electronic device used to suppress interference that is present on a signal or power line. They can be used to suppress interference that is generated by the device they are connected to or by other equipment in proximity in order make that device more immune to electromagnetic interference signals present in the environment.
EMI filter

What is electromagnetic interference?

Electro-Magnetic Interference, is defined as unwanted electrical signals and can be in the form of conducted or radiated emissions. It is the interference caused by an electromagnetic disturbance affecting the performance of a device, transmission channel, or system. All integrated circuits are a potential source of EMI. EMI is either conducted – in which there is physical contact between the source and the affected circuits or radiated – which is caused by induction.

This interference can affect the performance of electronic equipment nearby. Equipment such as cordless telephones, home entertainment systems, computers, and certain medical devices can fail to work properly in the presence of strong electromagnetic fields.
Problems with EMI can be reduced by ensuring that components such as EMI filters are installed. EMI filters can suppress any interference that is generated by the device or by other equipment in order to make a device more immune to electromagnetic interference signals present in the environment.

Why do we need EMI Filters?

There are regulatory standards in most countries that limit the amount of high frequency electromagnetic interference that can be emitted by a device and EMI filters function to help maintain or reduce this level.

In addition to assisting to meet EMI regulations, the filter also has to meet a number of safety standards to reduce the risk of fire and electrical shock. AM Transformers have over 20 years’ experience in the industry and you can be certain that our products meet all standards.
There are many different kinds of EMI filters. At AM Transformers we supply custom and standard common mode EMI line filters which are designed to prevent noise emission in switching power supplies at input and to prevent high-frequency noise in communications equipment such as facsimiles, etc.

Contact us today.