SCHMITT TRIGGER USING 741 OP AMP Schmitt Trigger is a Comparator and it is known as Squaring circuit because it converts an irregular shaped waveform to a square wave. The output voltage changes its state every time when input voltage crosses the threshold level. The input voltage at which the output switches from +Vsat to -Vsat is called the Upper Triggering Point (UTP). The input voltage at which output switches from -Vsat to +Vsat is called Lower Triggering Point (LTP). Read More.....