Hello all, I'm incredibly new to electronics and am taking an instrumentation course this fall to finish out a chemistry degree. Intro aside, we did our first lab today which involved making a low pass filter to turn triangular waves into sine waves - turned out to be pretty simple after I figured out how a circuit board works and where to plug in cords. The part we were supposed to figure out on our own was turning a square wave into a sine wave using a low pass filter (or some variation). Like I said, I'm really new to this so I just basically started sticking capacitors and resistors in every order I could think of on the circuit board. That didn't work, so I started varying the frequency and turning knobs on the oscilloscope while I was at it. Nothing I did worked, so I came home to research what I could on the internet. There seems to be plenty of active filter information (using opamps which we just learned about today in lecture), but the only useful information I could find was in this forum in a post that mentioned "resonance" using more than one low past filter http://forum.allaboutcircuits.com/showthread.php?t=12501 (last comment). Is this the right direction, or is there some other method that I'm failing to figure out here? I get the feeling that the solution is probably something simple, even by introductory standards, but for the life of me I'm at a loss. Thank you for your help.