When I measured the voltages for my implementation of a Schmitt Trigger based on a CD4007 chip, I was confused by the shapes of Vx and Vy. In particular, I find that the voltage Vx saturates at about 1.9V (please see attached PowerPoint file).
When the transistors N1 and N2 are cutoff, why does Vx not approach VDD?
Why do Vy and Vx have different shapes?