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.
Found in a 1967 American electronics magazine, this circuit has an input impedance of 2000 ohms....
This circuit makes use of components from the time it was published. The TCA151 is not a common...
This ultrasonic insect repellent was found in American documentation from the 1980s. The...