Using the LM3909 this circuit was found in the January 1992 issue of Radio Electronics magazine. Resistor R1 should be chosen according to the table given next to the diagram.
This circuit turns on an old cassette recorder when the telephone rings, thus enabling the...
This circuit was found in a Poptronics of the 90's. The circuit limits the load current to 0.6 A....
Incandescent lamps and heaters can be controlled by a low power switch using this circuit. The...