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 has a traditional configuration explored in several other points of this site. The...
We found this traditional flasher configuration in a June 1969 Radio Electronics magazine. SCRs...
This circuit was obtained in a 1979 publication. The operational amplifier is of the type with...