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 sensitive electrostatic charge detector uses only common discrete components. The circuit can be...
This 9-pixel circuit has been implemented with 9 LDRs and can be coupled to a processing system for...
This is a well-known RC oscillator configuration using a 741 operational amplifier. The circuit is from...