A basic Schmitt trigger realized with an operational amplifier.
A sine wave signal is sent to the OpAmp inverting input, while the non-inverting one is connected to the output through a resistive feedback network. If the amplitude of the sine wave is greater that the difference between the highest and the lowest signal amplitudes sent to the non-inverting input (the so-called "hysteresis level"), then hysteresis is visible by plotting Vout vs. V- = Vs .
