This speaker overload protection circuit was found in Radio Electronics from the 1980s. The circuit uses a 9 V relay but can be powered by 12 V for a relay of this voltage.
Old phones with dials can be used in a simple home intercom system, as this circuit from Popular...
This circuit was found in the July 1992 issue of Radio Electronics magazine. The circuit has a...
This simple circuit indicates if the polarity of a load is reversed when it is connected to a...