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 is suggested by Texas Instruments and can be used on an assembly line to drive an...
In the figure we have a interfacing circuit of TTL logic as CMOS logic using a 6N139 optical...
This alarm with sensors in series and parallel was found in the 1995 Encyclopedia of Electronic...