Active filters use amplifiers (op-amps) to create the appropriate filtering effect and provide benefits that can’t be derived from passive filters. The use of one or more op-amps results in a filter with high input impedance, low output impedance, and will prevent the load impedance from altering the filter properties. Active filters can create complex poles and zeroes in the frequency response using only resistors and capacitors in the feedback loop of the op-amp. This eliminates the need for inductors, which leads to filters with lower cost, smaller size, and higher accuracy.What are the different types of active filters?Multiple active low pass filter topologies exist that can be used to implement the same types of filters commonly created with passive filtering, including active low-pass filters, active high-pass filters, active band-pass filters, as well as notch and elliptic filters. Multiple filter stages can be cascaded to create higher order active filters, allowing for overall higher order filters. The use of op-amps does limit the bandwidth and power levels the filter can handle in an active filter circuit.Shop Arrow’s selection of active filters and low-pass filters today. Read more Read less