In the last edition of Don’t Fear the Filter, we built up two examples of the simplest and most-used active filter of all time: the two-pole Sallen-Key lowpass. This time, we’re going to put two of ...

This article is part of the Ideas for Design Series: Vol. 3, No. 9. Many communications and sensor applications require a bandpass filter with wide bandwidth. This filter typically requires precision ...

One of the great things about the Hackaday community is how quickly you find out what you don’t know. That’s not a bad thing, of course; after all, everyone is here to get smarter, right? So let’s ...

DELTA has lifted the application range of variable filters to new levels by introducing a new powerful type of linear variable filter (LVF). Since DELTA offered the first linear variable filters in ...

Several manufacturers offer op amp-based filter design tools [1-3]. Some tools choose off-the-shelf capacitor values, but others select non-standard ones. The option to alter passive component ...

This article originally appeared in the March 2007 issue of Astronomy. Only one star, the Sun, lies close enough to resolve through amateur telescopes. Observing the Sun provides a superb daytime ...

Active lowpass filters can have a wide range of AC response characteristics but they all have one thing in common, and that’s that they pass DC. Like other analogue ...