An example of high-pass active filter of the Sallen–Key topology. The operational amplifier is used as a buffer amplifier. An active filter is a type of analog circuit implementing an electronic filter using active . At low frequency it is better to use active filter and at high frequency it is better to use passive filter. Good linear phase
behave like high pass filters, they attenuate low frequencies and pass high frequencies. Low Pass Filters: filters that attenuate high frequencies. The term active is used because the op amps themselves require their own power supply,.
The simplest filters, and crudest, are first order high pass filters and first order low . This is called a high pass filter because frequencies above ωc = 1τ tend to be .. to get good inductors for filters below 1kHz, people often use active filters in