A filter is a circuit that removes unwanted frequencies from a signal. There are many different types of filters. Electronic filters can be passive or active; high-pass, low-pass, band-pass, band-stop or all-pass; analog or digital; linear or non-linear and much more.
Low-pass filterLow-pass filter
A low-pass filter removes all frequencies above the cutoff frequency. This frequency is determined by the values of the components.
High-pass filterHigh-pass filter
A high-pass filter removes all frequencies below the cutoff frequency. This frequency is determined by the values of the components.