A Noisy
Schmitt Trigger input signal near one
threshold can result only one switch in
output value, and it goes to the other
threshold in order to cause another
switch.
The benefit of a
Schmitt trigger over a circuit with
only a single input threshold is greater
stability (noise immunity).
The
Schmitt trigger is a comparator
application which switches the output
negative when the input passes upward
through a positive reference voltage
The required circuit is called a
Schmitt Trigger. It has two
possible states just like other
multivibrators.