An LC filter is an electronic circuit that uses an inductor (L) and a capacitor (C) to filter signals. It can be designed to allow certain frequencies to pass while blocking others, making it useful in various applications like audio processing and radio communications. The combination of the inductor and capacitor creates a resonant circuit that can either pass or attenuate specific frequency ranges. There are two main types of LC filters: low-pass and high-pass. A low-pass filter allows signals below a certain frequency to pass through while attenuating higher frequencies. Conversely, a high-pass filter does the opposite, allowing higher frequencies to pass while blocking lower ones. These filters are essential in managing signal quality and reducing noise in electronic systems.