Found in an old Popular Electronics this circuit can also be adapted to be used as a shield. In this version the control can trigger loads from the light that falls on an LDR.
This circuit was obtained in a 1967 General Electric manual. The circuit applies to other triacs....
Found in an October 1992 Radio Electronics magazine article, this circuit generates a low-power tone in...
This circuit was obtained from an American 80's documentation. The operational ones can be...