Due to the large positive feedback and asymmetric limiting voltages away from the +/- supplies, non-ideal results are expected. Also the since the Op Amp has a 1st order integrator internally to make it unity gain stable, the slew rate is far less than a comparator or a CMOS Schmitt Inverter which have symmetrical waveforms.
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I used Falstad's browser based simulator with the LM324
Dana, thanks for the reply. It may take a little for me to get may head around this. Are you saying that since there is positive feedback, the op amp exhibits hysteresis? So when the output is positive, divider voltage greater than capacitor voltage and the capacitor voltage rising, the output will not flip to negative until the capacitor + a little hysteresis voltage is greater than the divider voltage? Is the hysteresis dependent on the positive feedback? Or is it naturally there? Does a data sheet mention this? Again, being a beginner most of this is new to me. Thanks for the help.
So when the output is positive, divider voltage greater than capacitor voltage and the capacitor voltage rising, the output will not flip to negative until the capacitor + a little hysteresis voltage is greater than the divider voltage?
Is the hysteresis dependent on the positive feedback? Or is it naturally there?
Yes I knew that , but it wasn't worth correcting as the waveforms only affect frequency from positive feedback ratio. What's the big deal?You used the wrong value R for the + fdbk.....
Regards, Dana.
What's the big deal?
Doesn't to me either but I got you beat by two years.1972 doesn't seem that long ago to me, I was 30 at that time
Look up LTspice tutorial.I downloaded LTSpice, but am having a devil of a time getting it to do what I want. Sure would be nice if there was a 'how to' manual for us beginners.
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