I wrote:
That is especially important for U2 and U3,, which are both open-loop, without any negative feedback.? Configured that way, they act like comparators, with outputs that are unbounded.? The only thing keeping their output voltages from increasing indefinitely, is that they have a finite slew-rate, and the outputs are still slewing (ramping) when the input changes polarity and they start slewing in the opposite direction.
I'm somewhat incorrect, in my explanation.? It is not the finite slew-rate that limits their output voltages.? It is the finite open-loop voltage gain, which defaults to Aol=100K.? They amplify the triangle waves from 24 V peak-to-peak, up to 2.4 MegV peak-to-peak.? The finite gain-bandwidth product (GBW=10Meg) makes their outputs a little less than that - only about 1.75 MV instead of 2.4 MV - but you get the idea.? Those amps never clip, so their outputs can be enormous.
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Use a UnicersalOpAmp2 instead.? You will have to give them supply voltages too, of course.
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Andy
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