Even though we publish new blogs daily from your intrepid editor and a number of well-known writers, sometimes it's good to have a look back at our well-received articles from the recent past.
We touched on the basics of active filter designs once before when we looked at integrators in Op-Amp & Integrator Basics. This time, we go in deeper and look at active filters with more than one pole. Like the integrator, the active filter is constructed around an op-amp. The author of this article looks at the two common topologies: the Sallen-Key (a non-inverting filter); and the infinite-gain, multiple-feedback (an inverting filter):
The author also discusses sensitivity issues — how the filter behaves as the resistor and capacitor values deviate from the calculated values. All good stuff to know for your next filter design. Have a look here.