This circuit that we found in a 1990 documentation uses an LED as a sensor. The operational amplifier is equivalent to the 741 and the trigger adjustment is made in the potentiometer.
This circuit was found in an old publication and can be adapted for use with modern...
Rectangular signals up to a few hundred kilohertz can be generated with this circuit, which is...
The lie detector we presented was created by a professional detective and found in a 1982...