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.
We found this circuit in the 1994 Linear Applications Handbook from National Semiconductor. The...
This circuit is from an Electronics World of 1968. The transistors are of the time and the power...
This circuit checks the infrared emission of a common remote control. We found it in the March 1993...