Using a dual 555 CMOS this very useful circuit on the bench was found in the July 1998 Electronics Now magazine. The circuit is battery powered.
This sophisticated audio voltmeter circuit was published in the March 1966 Radio Electronics...
This immobilizer circuit for the car was found in the Radio Electronics magazine of December 1976....
This 50 Hz rejector or notch filter was found in a 1975 documentation. Other frequencies can be...