I ran into a seemingly odd result the other day in a simulation I was running on Multisim 12 using the three terminal virtual op-amp. This sketch shows. Aspencore network. News & Analytics ... 3 ...

The generator does not work yet, but I need to get a replacement op amp before I troubleshoot it. 10. The +20-V power supply must work in order for the −20 V, +17 V, and −17 V supplies to work.