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.
With this luminous remote control, which we found in a 1990 publication, using a flashlight you...
We found this circuit in a 1967 Electronics World. The circuit can be designed to control other...
This circuit can be used in a signal level indicator with LEDs. The circuit is from an Electronics Now...