What is an EMI Filter?

To keep powerful, sophisticated electronic devices functioning properly, protection from electromagnetic interference (EMI) is a must. EMI is unwanted noise or interference in an electrical circuit caused by other electromagnetic fields. This all-too-common issue can cause systems to work less optimally and sometimes stop functioning altogether, which can become a real cause for concern in medical devices such as pacemakers or vehicle safety devices. An EMI filter is an EMI shielding device that can help protect devices.

Like a water filter that filters out contaminates, an EMI shield filters out unwanted electromagnetic waves. While an EMI shield provides protection for an entire circuit, an EMI filter targets specific noises or sources. Filters can work on top of shields to provide additional protection for outputs and inputs and shore up any potential vulnerabilities. 

EMI filters typically contain passive components such as capacitors and inductors that are connected together to form LC circuits. These capacitors and inductors play an important role in providing the necessary EMI protection. The inductors block the noise while allowing direct current and low-frequency currents to flow through. And, the capacitors enable a low-impedance path that diverts the noise back to a safer source, such as the power supply or ground connection. 

There are several EMI filtering products that meet specific industry needs and design requirements. Parker Chomerics is a leader in this space, working closely with our customers to provide proven solutions they can trust.

Do you mean shielded air filter?

Parker Chomerics STREAMSHIELD™ Vent Panels are a high-performance, economical solution to EMI and airflow issues for telecommunications and information technology markets. Combining maximum shielding with minimal air flow resistance to provide optimal airflow for cooling electronic enclosures, our EMI shielding air ventilation panels come in a range of configurations to deliver high-performance shielding.

Do you mean shielded optical filter?

Parker Chomerics WIN-SHIELD™ EMI Shielded Plastic Windows provide EMI shielding while maximizing display performance by using specially engineered optical materials that enable viewing under the most challenging conditions. Widely used in the life sciences industry, this solution is highly customizable and can be paired with Chomerics CHO-BOND^® 578 silver epoxy or CHO-FOIL^® metal adhesive tape for grounding purposes.

Learn more about additional high-performing EMI shielding solutions.