We obtained this circuit in a technical documentation from the 90's. The circuit has its sensitivity adjustment in the potentiometer. The supply voltage can be reduced with a 1k resistor change.
This simple circuit controls the signal amplitude through a photoresistor optical coupler. The...
This circuit can be implemented with standard photodiodes consisting of a two input optical AND gate....
In the figure we have the basic configuration of an operational amplifier for audio signals. The...