Line Filters

A line filter is a wound inductive element, generally combined with line-to-line and line-to-ground capacitance, inserted in series with an AC or DC feed to attenuate high-frequency conducted noise and help equipment meet EMI compliance limits. It presents high impedance to noise current at the frequencies of concern while passing the supply fundamental with minimal insertion loss. Parts are specified by rated current, rated voltage, and an attenuation target over a stated frequency range, with common-mode inductance and leakage current recorded as electrical properties on the part's spec sheet rather than sold as a separate product. Leakage current at rated voltage matters most on grounded systems, since it bounds how much filter capacitance the installation can tolerate. Aslan builds to the customer's current, voltage, and attenuation requirement rather than to a single fixed catalog value.