The Role of EMI Suppression Filters

Astrodyne TDI is a top-tier supplier of stock and customized electromagnetic interference (EMI) filters. We've been engineering and manufacturing power supplies for decades, including developing EMI filters for commercial, industrial, medical, and military applications. Our team has built a legacy of excellence and a reputation as a leading manufacturer that helps companies remain compliant with electronic and energy standards. 

Defining the EMI Filter 

It's critical to understand the basics of EMI filters to choose the right solution for your company. EMI occurs when an unwanted electric current interrupts the intended flow of currents received by an electronic device and causes a disruption in the device's functionality.

An EMI suppression filter attaches to devices or circuits and suppresses electromagnetic noise that would interfere with the device's functionality. The filters extract the unwanted current from cables to allow the intentional currents to flow without interruption. Electromagnetic noise typically operates at a high frequency, so many EMI filters are low-pass, acting as a sieve to filter out the specific noise frequencies. 

EMI Filter Applications Explained

There are a wide variety of real-world EMI filter applications in many industries. In any environment that requires electronics to work in harmony without creating interference, EMI filters provide a benefit.

The many applications for power EMI filters include:

  • Military or Aerospace Systems and Subsystems
  • Energy Management Systems
  • Test Chambers or Shielded Rooms
  • Appliances
  • Magnetic Resonance Imaging (MRI) Rooms
  • Computers
  • Automotive Battery Chargers
  • Factory Automation Equipment
  • Exercise Equipment
  • Industrial Equipment
  • Medical Imaging or Diagnostic/Patient Devices

The main three industries that depend on EMI filters for success include the health care, military, and commercial sectors.


Medical device filters typically have some of the most stringent spatial requirements because of the safety standards necessary to care for patients. For example, implantable medical devices like the pacemaker have extremely high standards for mechanical and electrical performance. The advancement of EMI filters now allows many pacemaker patients to use MRI technology, despite its large amounts of EMI.

These strict standards demonstrate that medical manufacturers need experienced designers with a history of regulatory compliance, durable designs, and high-quality manufacturing processes.


Defense electronics need to follow a series of regulations that govern every step in production, from manufacturing and testing to device performance. These filters need to withstand the harshest environments that many military operations experience. Specific types of filters are necessary for various branches of the military, including conducted emissions parameters for the Navy.


Commercial filter and device regulations vary based on the country where you sell products. Some countries regulate the number of hazardous materials found in electronics, while others have mandates regarding the emission of electromagnetic radiation. Most nations have specific regulations to prevent interference that dictate the approved type and amount of EMI a device can generate.

Integrated EMI Filters 

Astrodyne TDI offers a vast collection of standalone filters that you can test and verify to fit with the EMI standards for your product and industry. Our filter selection is also designed to integrate with our vast selection of other products.

We take this integration a step further by implementing our filter solutions into high-power AC front-end converter systems. Our team will work with you to meet your unique requirements through our mod standard design program. 

Astrodyne TDI also has extensive expertise in medical low-power EMI filters. Our experts can offer high-performance EMI filtering as an integral provision of AC/DC converters. These embedded, proprietary filter solutions conform to the very low levels of permissible leakage current in both body floating (BF) and cardiac floating (CF) electrical environments.

When you need an AC/DC power line filter solution, Astrodyne TDI is here to help. 

Contact Astrodyne TDI Today for World-Class EMI Solutions

Astrodyne TDI has more than 60 years of experience as an industry-leading AC noise filter manufacturer. Our team can develop a wide range of mod-standard and custom filters. We can also define the performance space when providing AC- and DC-rated filters, from very small to very high current levels. We offer unrivaled engineering support with samples at a two- to four-week turnaround, in-house safety certifications and pre-compliance support, and solution design for AC power line EMI filters.

Ready to explore power EMI filter options? Contact the Astrodyne TDI team online today to discuss your options.