This circuit was obtained from a Radio Electronics issue from January 1989. The indicator is a ceramic transducer, and the frequency of the emitted sound is given by C3.
This circuit is designed to activate an automotive alarm after 8 minutes of activation. Of course...
The coils determine the frequency of this oscillator that we found in the January 1996 issue of...
This simple timer can be used in many applications such as egg timer. The LED glows up when S1 is...