This simple timer with unijunction transistor was found in an old American technical documentation. We can use 2N2646 for the unijunction and BC548 for the transistor.
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...