This biestable vox circuit was found in an old documentation. The circuit makes use of components of the time (80's) and can work as a shield since the power is 5 V.
This circuit, published in the 1980s, can be applied to operational amplifiers of almost any type....
We found this very simple cable fitting circuit in an Electronics Now from the 90s. ...
This circuit is nothing more than a turn signal for two alternating LEDs that can decorate a robot...