The configuration shown was found in an old Poptronics but can be easily assembled using a common calculator photocell. The relay is according to the supply voltage.
This circuit was suggested by General Electric in a 1965 documentation. The circuit can be...
This circuit of an Electronics Now from the 90's produces an intelligent direction signal that has...
This simple amplifier stage with a transistor has a linear response from 25 Hz to 120 kHz. The...