This circuit was found in a 1992 publication. What it does is to light an external lamp when it gets dark. The trigger point adjustment is made in a potentiometer or trimpot and the sensor is a common LDR.
In the figure we show an interesting application for integrated circuit 4001. This circuit causes a...
The operational 3403 is not currently common, but a similar configuration can be made with modern...
Found in a 1954 documentation, this circuit uses a germanium transistor from the time. The coil...