Understanding the Switching of a Schmitt Trigger

The tent function used to understand the switching was generated in Excel and used as an input to the Multisim PWL. The Schmitt trigger is a closed loop op-amp comparator with positive feedback (in contrast to an open loop op-amp comparator). The positive feedback provides increased noise immunity to the switching when the input voltage is in the vicinity of Vref. It also turns a slow rising signal into one with rapid switching edges.