An EMI filter circuit is an electronic circuit designed to reduce the level of electromagnetic interference (EMI) in a signal path, typically by filtering out common-mode signals and impedance-matching the circuits of the signal path. EMI filters are used in a variety of applications, including computers, telecommunication equipment, medical equipment, home electronics, and more. EMI filters are composed of capacitors, inductors, resistors, and other active components, which help reduce the electromagnetic interference caused by other electrical components in the system. EMI filters also help reduce crosstalk, which occurs when two circuits exchange electrical energy and signals without actually making direct contact.