Hi all, I am writing a tutorial page for students currently not attending school. It's about opamps with capacitors in their feedback loops, used as filters. See attached circuits, the simplest of the simple! On the left, the low-pass circuit is quite commonly shown in website tutorials with in-depth analysis, equations, graphs, etc. I thought that the same would be found for the high-pass circuit at right, but not so. Why not? Is there something wrong with it? Are the two circuits not different versions of the same thing? All comments gratefully received. Thanks.