The Schmitt trigger circuit is named after its inventor, the American physicist Dr. Otto H. Schmitt, who first described it in 1934.
The Schmitt trigger circuit is sometimes referred to as a regenerative comparator, because of its ability to regenerate or amplify a weak input signal.
This is accomplished by using two transistors, connected in a positive feedback loop, which amplifies the input signal.
The input signal is applied to the base of the first transistor, which then amplifies the signal and applies it to the base of the second transistor.
The second transistor then amplifies the signal even further, and the output is taken from the collector of the second transistor.
The Schmitt trigger circuit is very useful in digital logic circuits, because it can convert a slowly changing input signal into a rapidly changing output signal.