Signal filters block or decrease (attenuate) unwanted frequencies or signal wave characteristics

Active filters are electronic filers that use active components such as voltage amplifiers or operational amplifiers.

Electromagnetic (EMI) filters and radio frequency interference (RFI) filters purify signals by attenuating the high-frequency RFI (typically 150kHz and up) and passing the low frequency EMI

Active low pass filters pass signals from low frequencies and reject signals from high frequencies

Active band pass filters are used to attenuate frequencies below and above a range of frequencies (i.

Active high pass filters pass signals from high frequencies and reject signals from low frequencies

Passive filters are implemented using only passive components such as resistors, capacitors and inductors.