1. The problem statement, all variables and given/known data The assignment is to create a square wave oscillator using an op-amp in Multisim. The wave's frequency should be 1 kHz and the duty cycle 60%. 2. Relevant equations f = 1 / (R*C) R1 < R R1 < Rf I guess. 3. The attempt at a solution Here's what I've done: http://img156.imageshack.us/img156/8494/sqwavegenaj6.png [Broken] (It's such a basic textbook example.) I don't know why the wave form looks like that. The problem is those unnecessary "bumps" that should be flat: http://img403.imageshack.us/img403/4951/osczh4.png [Broken] Am I doing something wrong (very probable) or what?