On Wed, Jul 20, 2011 at 8:03 AM, Herbert Graf wrote: > On Wed, 2011-07-20 at 07:53 -0400, V G wrote: > > Please refer to the screenshot: http://solarwind.byethost7.com/pic1.png > > > > I have a 10kHz sine wave at the input of the opamp and a 0.1ms transien= t > > analysis. What I see in the graph does not appear to be my input wave. > Also, > > why is the output shifting up and down like a wave itself? > > The shifting up and down is your amplified 10kHz signal. Realize that > 10kHz corresponds to 100us for one cycle. > > The much shorter period oscillation is something to do with your circuit > being unstable. You're probably overlooking something in the datasheet > for that particular op-amp. > > It's also possible you've hit a bug in either ltspice or the model for > one of your components. > > TTYL > > I don't know that I'd call it a "bug", I think it's more of a case of "In theory, theory and practice are the same. In practice, they are not." I'd think that in a real circuit, stray parasitic capacitance would be enough to calm this down. It's a reminder that the circuit board is more than just a mounting device. -Denny --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .