Another "Unknown subcircuit called in" message

Hi rdpoor,

Sorry I forgot to mention this before:

The "opamp" device you used is a very ideal, non-realistic op-amp model.  Notice that it has no supply voltages.  There is nothing to limit its output voltage, and some circuits could drive its output voltage towards infinity.  It is OK 99% of the time, but occasionally it does not produce the results that you wanted.

Also, your circuit seems to be missing something.  I think you might not have drawn it the way you wanted.  It appears to have positive feedback around the first op-amp, except that the op-amp is also driven by an ideal voltage source, so the wiper of the potentiometer seems to have no real purpose.  Also note that it would make no sense either if wiper=0 (U1's output short-circuited to V1), or if wiper=1 (U2's output short-circuited to V1).  Both of those seem wrong.  Or maybe I misunderstood.

Regards,

Andy

Hi rdpoor,

Sorry I forgot to mention this before:

The "opamp" device you used is a very ideal, non-realistic op-amp model.  Notice that it has no supply voltages.  There is nothing to limit its output voltage, and some circuits could drive its output voltage towards infinity.  It is OK 99% of the time, but occasionally it does not produce the results that you wanted.

Also, your circuit seems to be missing something.  I think you might not have drawn it the way you wanted.  It appears to have positive feedback around the first op-amp, except that the op-amp is also driven by an ideal voltage source, so the wiper of the potentiometer seems to have no real purpose.  Also note that it would make no sense either if wiper=0 (U1's output short-circuited to V1), or if wiper=1 (U2's output short-circuited to V1).  Both of those seem wrong.  Or maybe I misunderstood.

Regards,

Andy