Found in an old Popular Electronics, this circuit warns when a remote lighting system is not working. The circuit uses an LDR as a sensor and the components used are quite common today.
These simple weapon and target circuits with emitter and photoelectric sensor were found in a 1985...
We found this circuit in an old publication dealing with operational amplifiers. The circuit uses...
Suggested by General Electric in a 1967 documentation, this circuit replaces the Thryraton tubes used at...